MHOs toward HMOs: A Search for Molecular Hydrogen emission-line Objects toward High-Mass Outflows
aa r X i v : . [ a s t r o - ph . S R ] J un Draft version July 23, 2018
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MHOS TOWARD HMOS: A SEARCH FOR MOLECULAR HYDROGEN EMISSION-LINE OBJECTS TOWARDHIGH-MASS OUTFLOWS
Grace Wolf-Chase,
1, 2
Kim Arvidsson, and Michael Smutko Astronomy DepartmentAdler Planetarium1300 S. Lake Shore DriveChicago, IL 60605 Dept. of Astronomy & AstrophysicsUniversity of Chicago5640 S. Ellis Ave.Chicago, IL 60637 Trull School of Sciences and MathematicsSchreiner University2100 Memorial Blvd.Kerrville, TX 78028 Center for Interdisciplinary Exploration and Research in Astrophysics (CIERA)& Dept. of Physics & AstronomyNorthwestern University2131 Tech DriveEvanston, IL 60208
ABSTRACTWe present the results of a narrow-band near-infrared imaging survey for Molecular Hydrogen emission-line Objects(MHOs) toward 26 regions containing high-mass protostellar candidates and massive molecular outflows. We havedetected a total of 236 MHOs, 156 of which are new detections, in 22 out of the 26 regions. We use H µ m/H µ m flux ratios, together with morphology, to separate the signatures of fluorescence associated with photo-dissociation regions (PDRs) from shocks associated with outflows in order to identify the MHOs. PDRs have typicallow flux ratios of ∼ ∼ ∼ Keywords:
ISM: jets and outflows—stars: formation—stars: massive—stars: pre-main sequence—stars: protostars
Corresponding author: Grace [email protected] INTRODUCTIONOutflows play an important role in the formation of stars across the entire stellar mass spectrum (e.g., Bally 2016);however, the nature of that role in the formation of stars > ⊙ remains poorly understood, since massive stars formin highly clustered environments that contain a mix of objects in different evolutionary stages. Zhang et al. (2005;hereafter, ZHB05) detected a total of 39 molecular outflows towards 69 luminous IRAS point sources associated withdense molecular gas and far-infrared luminosities indicative of massive star formation. From observations of the COJ=2 → ∼ ′′ , they presented maps and derived physical parameters for 35 of theseoutflows, showing that their mass, momentum, and energy range from one to a few orders of magnitude larger thantypical values for outflows associated with low-mass young stellar objects (YSOs). Although nearly half of the outflowsmapped show spatially resolved bipolar lobes, the remainder show complicated lobe morphology or little evidence ofbipolarity, and in several cases, the outflow centroid is clearly offset from the IRAS point source position.The H µ m is a powerful tracer of shocks in molecular outflows (Davis et al. 2010 and referencestherein; Smith 2012). It can be used to identify collimated outflows and candidate driving sources even in massivestar-forming regions (e.g., Varricatt et al. 2010; hereafter VDR10), with the caveat that H emission produced byshocks (Molecular Hydrogen emission-line Objects or MHOs) is typically interspersed with fluorescent emission fromphoto-dissociation regions (PDRs) associated with expanding H II regions. Although morphology of the H emission istypically used to distinguish MHOs, H µ m/2.25 µ m flux ratios provide a more robust method for separating theeffects of shocks and fluorescence (Wolf-Chase et al. 2013; hereafter, WAS13). To investigate the relationship betweenmassive CO outflows, MHOs, and their driving sources, we acquired 4. ′ × ′ ∼ ′′ toward 25 of the CO outflows mapped by ZHB05 and one outflow mapped by Zhang et al. (2007).This paper is organized as follows. Details of the observations and data reduction are presented in §
2. Table 1 liststhe observations for all targets. Results and discussion of the survey are presented in §
3. Table 2 indicates whethertargets contain detected MHOs, catalogued H II regions, and catalogued massive young stellar objects (MYSOs).Table 3 lists the positions and fluxes of all MHOs for each target where MHOs were detected. Table 4 lists candidateoutflows and driving sources. Our summary and conclusions are presented in §
4. Images, results and discussion ofindividual regions containing MHOs are presented in Appendix A, except for Mol 121 & Mol 160, which were publishedpreviously (WAS13; Wolf-Chase et al. 2012, hereafter WSS12). OBSERVATIONS AND DATA REDUCTIONWe obtained H µ m, H µ m and H r 2.13- µ m (narrow-band continuum) images of 26 regions thought tocontain massive YSOs, using the Near-Infrared Camera and Fabry-Perot Spectrometer (NICFPS: Vincent et al. 2003;Hearty et al. 2004) on the Astrophysical Research Consortium (ARC) 3.5-m telescope at the Apache Point Observatory(APO) in Sunspot, NM. All targets contain energetic molecular outflows identified through CO observations andthought be associated with massive YSOs (ZHB05 Table 2; Zhang et al. 2007). Table 1 lists the targets by IRAS designation (column 1) and Molinari number (Molinari et al. 1996, 1998, 2000, 2002), center position (columns 2 & 3),filter (column 4), date (column 5), total exposure time (column 6), and resolution (column 7) as determined by seeingconditions at the time of the observations. We used the narrowband filter centered on 2.13 µ m to allow for continuumsubtraction in the final images. All images were acquired with a 4. ′ × ′ ′′
273 pixel − .Our basic data acquisition, reduction, and calibration methods are described in WSS12, and the methods we used toperform irregular aperture photometry on extended emission are presented in WAS13.The target regions have varying brightness and morphologies, as well as varying background emission, which makes itimpossible to apply one criterium for the spatial extent of all suspected MHOs. Rather, the morphologies of the regionsused for aperture photometry were determined by signal-to-noise with respect to the background in the continuumsubtracted images. To reduce the effect of the patchy nature of the extended background emission in continuumsubtracted images, the images were smoothed using a 3-pixel Gaussian and the resulting background noise measured.The regions were then chosen to trace contours of multiples of the smoothed background noise. This could range from10 times the background noise in the fainter regions to 60 times inside some of the brighter emission, but for mostregions, 20 to 40 times the background noise contours were used. Whenever possible, the regions were chosen to traceemission that has approximately the same morphology in both 2.12 and 2.25- µ m images. HOs toward HMOs Table 1 . Observation Log
Source α (J2000) δ (J2000) Filter UT date Exposure FWHM(2.12 µ m)IRAS (Mol) h m s ◦ ′ ′′ (yymmdd) Time (s) (arcsec)00117+6412 (2) 00 14 27.7 +64 28 46 H µ m 071218 1800 0.85H µ m 071218 1800H r 2.13 µ m 071218 180000420+5530 (3) 00 44 57.6 +55 47 18 H µ m 071119 1800 0.87H µ m 071119 1800H r 2.13 µ m 071119 180005137+3919 (8) 05 17 13.3 +39 22 14 H µ m 071203;070227;070204 4800 0.94H µ m 071203 1800H r 2.13 µ m 071203;070227;070204 480005168+3634 (9) 05 20 16.2 +36 37 21 H µ m 071218 1200 0.79H µ m 071218 1200H r 2.13 µ m 071218 120005274+3345 (10) 05 30 48.0 +33 47 52 H µ m 080115 1800 1.48H µ m 080115 1800H r 2.13 µ m 080115 180005345+3157 (11) 05 37 47.8 +31 59 24 H µ m 051224 3900 1.17H µ m 061013 1800H r 2.13 µ m 051224 390005373+2349 (12) 05 40 24.4 +23 50 54 H µ m 080319 1680 1.03H µ m 080319 1680H r 2.13 µ m 080319 168006056+2131 (15) 06 08 41.0 +21 31 01 H µ m 061010;061013 3000 0.84H µ m 061013 1200H r 2.13 µ m 061013 300006584 − µ m 070227;070327;080319 5400 1.21H µ m 070327;080319 3600H r 2.13 µ m 070227;070327;080319 540018532+0047 (78) 18 55 50.6 +00 51 22 H µ m 060612;060613 4500 1.38H µ m 080611;080915 1800H r 2.13 µ m 060613;080611;080915 450019213+1723 (103) 19 23 36.9 +17 28 59 H µ m 060513;060514 5400 0.98H µ m · · · · · · H r 2.13 µ m 060513 270019368+2239 (108) 19 38 58.1 +22 46 32 H µ m 060618 3240 0.87H µ m 080530 1680H r 2.13 µ m 060616;080530 324019374+2352 (109) 19 39 33.2 +23 59 55 H µ m 060606 2700 0.89H µ m 080519 1800H r 2.13 µ m 060606;080519 270019388+2357 (110) 19 40 59.4 +24 04 39 H µ m 080611 2400 1.12H µ m 080611 2400 Table 1 continued on next page
Table 1 (continued)
Source α (J2000) δ (J2000) Filter UT date Exposure FWHM(2.12 µ m)IRAS (Mol) h m s ◦ ′ ′′ (yymmdd) Time (s) (arcsec)H r 2.13 µ m 080611 240020050+2720 (114) 20 07 06.7 +27 28 53 H µ m 080729;080915 2100 1.00H µ m 080729;080915 2100H r 2.13 µ m 080729;080915 210020056+3350 (115) 20 07 31.5 +33 59 39 H µ m 080915;081109 2400 0.71H µ m 080915;081109 2400H r 2.13 µ m 080915;081109 240020188+3928 (121) 20 20 39.3 +39 37 52 H µ m 081013 1740 1.21H µ m 081013 1740H r 2.13 µ m 081013 174020220+3728 (123) 20 23 55.7 +37 38 10 H µ m 110620 1950 1.34H µ m 110620 1950H r 2.13 µ m 110620 195020278+3521 (125) 20 29 46.9 +35 31 39 H µ m 081111;081112 1800 0.99H µ m 081111;081112 1800H r 2.13 µ m 081111;081112 180020286+4105 (126) 20 30 27.9 +41 15 48 H µ m 110613 1800 0.80H µ m 110613 1800H r 2.13 µ m 110613 180021307+5049 (136) 21 32 31.5 +51 02 22 H µ m 070105 1800 1.09H µ m · · · · · · H r 2.13 µ m 070105 180022172+5549 (143) 22 19 09.0 +56 04 45 H µ m 050703;051011;051016;061202 4740 0.85H µ m 051016 3600H r 2.13 µ m 051011;051016;061202 474022305+5803 (148) 22 32 24.3 +58 18 58 H µ m 081109 1470 0.90H µ m 081109 1470H r 2.13 µ m 081109 147022506+5944 (151) 22 52 38.6 +60 00 56 H µ m 081111;081112 1800 1.00H µ m 081111;081112 1800H r 2.13 µ m 081111;081112 180023314+6033 (158) 23 33 44.3 +60 50 30 H µ m 071119 1800 0.93H µ m 071119 1800H r 2.13 µ m 071119 180023385+6053 (160) 23 40 53.2 +61 10 21 H µ m 050617 1800 0.75H µ m 071121 1200H r 2.13 µ m 071121 1200 SURVEY RESULTS AND DISCUSSIONTable 2 identifies target regions (columns 1 & 2) as
High (H) or
Low (L), depending upon whether the associated
IRAS source has infrared colors typical of an Ultra-Compact (UC) H II region or redder, respectively (Wood &Churchwell 1989; Palla et al. 1991). The designation (UC) indicates candidate UC H II regions based on the detectionof centimeter-radio continuum emission at levels > ′′ of the IRAS position (G´omez-Ruiz et al. 2016).Columns 3 & 4 indicate whether a targeted region contains MHOs and, if so, whether collimated outflow(s) could be
HOs toward HMOs
WISE catalog of Galactic H II regions within the targeted areas and theirclassifications by type (Anderson et al. 2014). Columns 7 & 8 list objects in the Red Midcourse Space Experiment ( MSX : Egan et al. 2003) Source catalog (RMS: Lumsden et al. 2013) located within each targeted region and theirtype. In § § § § Table 2 . Source Detections & Associations with Massive Star Formation
Source Type a MHOs? Collimated?
WISE
Name b H II Type b MSX
Name RMS Type
IRAS (Mol)00117+6412 (2) H(UC) Y Y G118.964+01.893 C · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · − · · · · · · G034.196-00.592 KG034.204-00.584 Q19213+1723 (103)* H(UC) N . . . G052.098+01.042 K G052.0986+01.0417 Diffuse H II Region19368+2239 (108) H Y Y G058.453+00.431 Q G058.4670+00.4360A YSOG058.467+00.436 Q G058.4670+00.4360B H II RegionG058.477+00.427 Q19374+2352 (109)* H(UC) Y N G059.602+00.911 K G059.6032+00.9116A H II RegionG059.612+00.917 G G059.6032+00.9116B H II RegionG059.6032+00.9116C H II RegionG059.6032+00.9116D H II Region19388+2357 (110)* H(UC) Y N G059.829+00.671 Q G059.8329+00.6729 YSO20050+2720 (114)* H Y Y · · · · · ·
G065.7798-02.6121 YSO20056+3350 (115)* H N · · ·
G071.312+00.828 C · · · · · · c * H(UC) Y Y G077.463+01.760 C G077.4622+01.7600A YSOG077.4622+01.7600B H II Region20220+3728 (123) H(UC) N · · ·
G076.180+00.064 Q G076.1877+00.0974 H II RegionG076.187+00.097 CG076.197+00.092 C
Table 2 continued on next page H O s t o w a r d H M O s Table 2 (continued)
Source Type a MHOs? Collimated?
WISE
Name b H II Type b MSX
Name RMS Type
IRAS (Mol)20278+3521 (125) L Y Y G075.155-02.087 Q · · · · · · II Region21307+5049 (136)* L(UC) Y N G094.263-00.414 C G094.2615-00.4116 YSO22172+5549 (143)* L Y Y · · · · · ·
G102.8051-00.7184A YSOG102.8051-00.7184B YSOG102.8051-00.7184C YSO22305+5803 (148)* H Y Y G105.509+00.230 Q G105.5072+00.2294 YSO22506+5944 (151) H Y Y G108.603+00.494 Q G108.5955+00.4935A YSOG108.5955+00.4935B YSOG108.5955+00.4935C YSO23314+6033 (158) L Y N G113.614-00.615 G G113.6041-00.6161 H II Region23385+6053 (160) d L Y N G114.526-00.543 C · · · · · · a Refers to objects that have
IRAS colors similar to ultracompact (UC) H II regions (H) and redder colors (L) (Wood & Churchwell 1989;Palla et al. 1991). The designation (UC) indicates a candidate UC H II region based on the detection of centimeter-radio continuumemission at levels > ′′ of the IRAS position (G´omez-Ruiz et al. 2016; Molinari et al. 1998; Palau et al. 2010; Kurtz etal. 1994). b Entries are from the
WISE catalog of Galactic H II regions (Anderson et al. 2014). Classifications indicate known (K) , grouped (G),and candidate (C) H II regions, and radio quiet (Q) objects. c G077.4622+01.7600A is coincident with core C and anomalous H emission reported by Wolf-Chase et al. (2013) and a deeply embeddedsource reported by Yao et al. (2000). d Bipolar, but very compact, MHOs about Mol 160 A (Wolf-Chase et al. 2012).
Note —Targets marked with an asterisk were included in a near-infrared imaging survey conducted by Varricatt et al. (2010).
Table 3.
MHOs and Fluxes.
Name MHO α (J2000) δ (J2000) Area F . F . F . / F . CommentsIRAS (Mol) h m s ◦ ′ ′′ − sr 10 − W m − − W m − . ± .
52 0 . ± .
11 15 . ± . . ± .
69 0 . ± .
14 16 . ± . . ± .
12 0 . ± .
06 7 . ± . . ± .
18 0 . ± .
07 9 . ± . . ± . · · · > . . ± .
53 1 . ± .
15 6 . ± . . ± . · · · > . . ± . · · · > . . ± .
69 0 . ± .
14 9 . ± . . ± .
19 0 . ± .
07 6 . ± . Note —Refs. - Chen et al. (1999, 2003, 2005); Khanzadyan et al. (2011); Varricatt et al. (2010); Wolf-Chase et al. (2012);Wolf-Chase et al. (2013) (This table is available in its entirety in machine-readable form.) H Emission
To choose our final list of MHOs, we excluded emission where the continuum-subtracted H µ m/H µ mflux ratio is <
3. Such emission is typically associated with fluorescence from photo-dissociation regions (PDRs) and isgenerally diffuse and extended. Some previously reported MHOs do not meet our flux ratio criterion, but are includedin Table 3 for the sake of completeness. We used morphology as an additional criterion to exclude PDRs, but in nocase did we find regions exhibiting PDR morphology (diffuse, extended arcs) where the H µ m/H µ m fluxratio is >
4. Since the vast majority of MHOs have flux ratios significantly greater, we are confident that this methodhas successfully identified the MHOs in our targets.For each target region containing MHOs, Table 3 lists its
IRAS source designation and Molinari number (column 1),identified MHOs (column 2), positions of the peak emission (columns 3 & 4), areas used in the aperture photometry(column 5), H µ m line fluxes (column 6), H µ m line fluxes (column 7), H µ m/H µ m flux ratios(column 8), and comments relevant to certain catalog entries (column 9). Where the H µ m line flux is below 3times the noise (3 σ ) within an aperture, the H µ m line is regarded as undetected and no value is given in column7. In these cases, lower limits to the H µ m/H µ m flux ratios are calculated using the 3 σ value for thataperture as an upper limit for the H µ m line flux.MHOs identified in Table 3 follow the numbering scheme used by the on-line catalog of these objects, which iscurrently hosted by the University of Kent and was initially published by Davis et al. (2010). In general, MHOs thatappear to be associated with linear features are assigned the same number and given additional letter designations toidentify individual knots. This is also the convention we use for MHOs that appear in groups. MHO numbers thatare followed by “ µ m/2.25- µ m ∼ −
4, and forthe lower-excitation C-shocks, ∼ −
20. Above 20, the excitation temperature is < http://astro.kent.ac.uk/~df/MHCat/ HOs toward HMOs µ m/2.25- µ m flux ratio <
1, which cannotbe explained by either fluorescence or shocks.3.2.
Relationship of MHOs to Massive CO Outflows
The targets for our survey were all chosen from sources associated with massive CO outflows listed in Table 2 ofZHB05, with the exception of Mol 10, which was mapped in CO by Zhang et al. (2007). We were able to identifyMHOs in 22 of the 26 regions we observed (Table 3). Across these 22 regions, MHO detections fall into 3 morphologicalcategories: (1) co-linear MHOs that define the position angle of one dominant outflow in the region; (2) multipleoutflows along different position angles; and (3) isolated or scattered MHOs where no clear outflows or position anglescan be identified. Table 4 lists candidate outflows (column 1) identified from MHO arrangements (column 2), possibledriving sources (column 3), outflow position angles (column 4), and distinguishing MHO features (column 5).In spite of the low resolution of the CO observations, there are several regions where chains of MHO detectionsfollow the large-scale morphology of CO outflows presented in Figure 1 of ZHB05, including Mol 8, 9, 11, 12, 15, 109,114 & 143. In some cases, both CO and H emission appear to trace PDRs or other complex structures (e.g., Mol2, 28, 126, & 136). This is not surprising, as CO emission has been associated with shells produced by expandingH II region bubbles identified from mid-infrared images (Dewangan et al. 2016; Churchwell et al. 2006). In a fewcases, there is no clear relationship between the CO and H emission (e.g., Mol 110, 125, 148, 151). There are severalpossible explanations for this: (1) While CO emission traces swept-up ambient material entrained in outflows, MHOstrace the current location of shocks, where the underlying wind is interacting with the ambient medium. It is possiblethat outflow axes change in time due to the precession of jets. (2) MHOs and CO emission may trace outflows fromdifferent sources. (3) Some differences may be explained by the size of the outflow and resolution of the observations.For example, Mol 151 displays a very compact ( < ′ in length) dramatic bipolar H jet along an east-west direction,while the high-velocity CO emission shows little evidence of bipolarity except for a small east-west separation of ∼ ′′ between the peaks of the blue- and redshifted lobes, comparable to the resolution of the CO observations (ZHB05).(4) In some cases, extinction effects and proximity to the edges of molecular clouds may explain observed differences.3.3. Association with H II Regions and YSOs
Table 2 lists all sources in the
WISE
Catalog of Galactic H II Regions (Anderson et al. 2014) that are found withinour targeted regions (Column 5). Column 6 indicates their classifications as known (K), grouped (G), candidate (C)or radio quiet (Q). K sources have measured Radio Recombination Lines (RRL) or H α emission that confirms theirH II region status; C sources are spatially coincident with radio continuum emission, but do not have RRL or H α observations; G sources represent K & C sources that are associated positionally, typically within the radius of a PDR;and Q sources lack detected radio continuum emission and are presumably associated with pre-UC H II region objectsor lower-luminosity intermediate-mass star-forming regions. Anderson et al. (2014) estimate that ∼
95% of C sourcesare bona fide H II regions.Ten of our target regions contain only Q sources (Table 2 - Mol 8, 10, 12, 15, 28, 108, 110, 125, 148, & 151),although two of these (Mol 15 & Mol 110) are identified as candidate UC H II regions by G´omez-Ruiz et al. (2016).All of these regions contain MHOs, and all but Mol 28 & 110 contain collimated outflows. Three of our targets withcollimated MHOs have no entries in the WISE
Catalog of Galactic H II Regions (Mol 9, 114, & 143). Of the fourregions that harbor K or G sources (Mol 78, 103, 109, 158), two lack MHO detections entirely (Mol 78 & 103) andthe other two (Mol 109 & 158) lack collimated flows. Although the three targets containing K sources all have
IRAS colors associated with ‘High’ (H) objects, there is no obvious relationship between H II region class and IRAS color.The regions containing only Q sources represent a mix of H & L objects.Table 2 also lists RMS sources found within our targeted regions (Column 7) and their type (Column 8). The RMScatalog is the largest statistically selected catalog of massive protostars and H II regions to date (Lumsden et al. 2013).It is thought to be complete for the detection of a B0 V star at the distance of the Galactic center, although inclusionin the catalog depends upon source detection by MSX and specific color criteria that may have excluded very young,compact objects containing a high fraction of ionized polycyclic aromatic hydrocarbons (PAHs) in thick PDRs (Kertonet al. 2015).We additionally used infrared color criteria established by Koenig & Leisawitz (2014) and Fischer et al. (2016)to identify candidate Class 0 and Class I YSOs from the
ALLWISE database, which combines data from the
WISE cryogenic and
NEOWISE post-cryogenic surveys (Wright et al. 2010; Mainzer et al. 2011). Class 0 and Class I YSOs0are associated, respectively, with protostars in the main and late accretion phases of pre-main sequence evolution(Lada 1987; Andr´e et al. 1993).Candidate Class I objects were required to satisfy all of the following criteria: W − W > . W − W < . W − W > . × ( W − W − . W − W > − . × ( W − W
3) + 2 . W − W < . × ( W − W − . W − W > WISE bands at 3.4 µ m, 4.6 µ m, 12 µ m, & 22 µ m, respectively.3.4. Candidate Driving Sources
Assuming collimated outflows are generated by circumstellar disks, one would expect them to shut off once massiveYSOs begin to ionize their surroundings. Since entries in the
WISE
Catalog of Galactic H II Regions were firstidentified by their characteristic mid-infrared “bubble” morphology, most of them are very large and clearly not goodcandidates for driving the collimated outflows identified in these regions. Four Q sources, which may be associatedwith younger or less luminous objects, do lie near the centers of outflows associated with Mol 8, 12, 15, & 148, but allare clustered with other candidate driving sources.RMS YSOs can be identified as candidate driving sources for collimated MHO outflows in Mol 8, 12, 15, 143, 148, &151. RMS YSOs may also drive MHO flows in Mol 10, 28, 110, 114, & 136, but the relationship is less clear cut, eitherbecause MHOs are either isolated detections or form linear arrangements offset from the YSO. (See Appendix A forfurther discussion.) We can also identify
ALLWISE sources that fit Class 0/I YSO color criteria as candidate drivingsources for outflows in 50% of the regions containing MHOs (11/22), with the caveat that candidates may containmultiple objects, since the resolution of
WISE at 22 µ m is 12 ′′ . Additionally, we note that some ALLWISE sourcesthat satisfy Class 0/I color criteria are coincident with bright MHOs, which suggests that in some instances, thesesources may be tracing shocked gas rather than YSOs. In any case, infrared colors alone cannot distinguish definitivelybetween different classes of objects and further observations will be required to confirm the natures of these sources.Table 4 presents 36 candidate outflows and driving sources, including cross-references to driving sources proposedin other publications. We identify candidate driving sources that fit
WISE
Class 0/I YSO color criteria (Koenig &Leisawitz 2014; Fischer et al. 2016) and/or are listed as YSOs in the RMS catalog for 26 of these outflows. We notethat only 3 of the 36 ( ∼ II regions; the remaining driving sources appear to beyounger objects. This suggests that the jet phase shuts off shortly after the YSO has begun to ionize it surroundings;however, future high-resolution observations of the candidate UC H II regions, particularly radio recombination linedata, would be particularly useful in establishing the evolutionary status of these objects. Seven of the candidatedriving sources of outflows listed in Table 4 are both RMS YSOs and YSOs we identified from ALLWISE sources.Only in two cases (Mol 10 Flow 4, Mol 151 Flow 1) is the proposed driving source a RMS YSO lacking a counterpartidentified from
ALLWISE . Although evidence suggests that most of the collimated outflows identified in this study aredriven by massive YSOs, much work remains to be done to establish source and outflow properties. NIR spectroscopyis needed to determine extinctions towards MHOs, which is essential for estimating MHO luminosities, and higherresolution observations are necessary to distinguish individual source contributions to bolometric luminosities. H O s t o w a r d H M O s Table 4 . Candidate Outflows & Driving Sources
Designation MHOs Candidate Source(s) P.A. MHOs NotesMol a , 75 bright knots, complex morphologyJ001427.00+642819.3,J001425.05+642822.4,J001423.45+642824.9,J001422.48+642836.8Mol 2 Flow 2 2968A-B MM1 a ? 10 bright knots, complex morphologyMol 3 Flow 1 2903 J004457.30+554718.1 (D)* 58 bow-shaped knot, faint bridge of emissionMol 3 Flow 2 2971-2974, 2976 J004458.06+554656.7 (B)* -80 curved chain of knotsMol 3 Flow 3 2969, 2970, 2900, 2975 J004457.30+554718.1 (D)*? 25 colinear knotsMol 8 Flow 1 1002,1003-1003 2 J051713,74+392219.6 (A,B)* 15-20 bright bow-shaped knots, precessing jet?(G168.0627+00.8221) RMS counterpartMol 8 Flow 2 1004 2, 1004 3 J051713,74+392219.6 (A,B)* -20 bright connected chainMol 9 Flow 1 1055G J052022.03+363756.5 60 bright bow-shaped featureMol 9 Flow2? 1055A,C,E J052022.03+363756.5 28 faint knotsMol 10 Flow 1 1005 MM-1/MM-2 (B)* 50 bright jetMol 10 Flow 2 1011, 1009, 1059? MM-1/MM-2 5 MHOs along “middle jet” b Mol 10 Flow 3 1057, 1007, 1060? . . . -60 MHOs along “long jet” c Mol 10 Flow 4 1006 G174.1974-00.0763 (A)* -90 bright bow-shaped featureMol 11 Flow 1 1015, 1015 2, 1015 3 J053752.03+320003.9 64 bright bow-shaped featuresMol 11 Flow 2 1061A-F J053752.03+320003.9? -72 linear chain of emission knotsMol 11 Flow 3 c Table 4 continued on next page Table 4 (continued)
Designation MHOs Candidate Source(s) P.A. MHOs NotesMol ∼ -87,-72 curved chain of knots, bright bowMol 121 Flow 1 d d e f compact ‘bipolar’ knots a Palau et al. (2010) b These outflows correspond roughly to jets identified by Chen et al. (2005) and Zhang et al. (2007). See Mol 10 section for details. c First identified by VDR10. d Wolf-Chase et al. 2013 e Wolf-Chase et al. 2012 f µ m point source (Molinari et al. 2008) Note —Sources marked with an asterisk were included in a near-infrared imaging survey conducted by Varricatt et al. (2010).
HOs toward HMOs SUMMARY AND CONCLUSIONS1. Using NICFPS on the ARC 3.5-m telescope at the APO, we have detected a total of 236 MHOs, 156 of whichare new detections, in 22 out of 26 regions associated with massive CO outflows.2. We find an excellent agreement between predicted H µ m/2.25- µ m flux ratios for shocks (H µ m/2.25- µ m >
3) and fluorescent emission (1 < H µ m/2.25- µ m <
3) and morphology: MHOs are typically “knots”,bow-shaped or other compact features, while fluorescent emission has the morphology of bubbles (e.g., as seenin regions Mol 2, 10, 11, 109, 125, 126, 151), filaments or arcs (e.g., Mol 3, 15, 136, 158), or pillars (e.g., Mol143). Based on low H µ m/2.25- µ m flux ratios, we note that some previously reported MHOs may havebeen misidentified as such.3. For MHOs with detected H µ m emission, H µ m/2.25- µ m flux ratios are typically between ∼ µ m/2.25- µ m < ∼
5, the MHO is either faint or lies in thedirection of a PDR. MHOs 1018 and 1018 3 in Mol 11 are good examples of the latter. A few MHOs have H µ m/2.25- µ m >
20 (e.g., the bright bow features MHO 1015 2 in Mol 11 and MHOs 2778 A&B in Mol 151),but in no case is H µ m/2.25- µ m >
30. Three of our survey targets, Mol 109, Mol 121 (WAS13), and Mol126, exhibit one or more spots where the H µ m/2.25- µ m flux ratio <
1, which cannot be explained byeither fluorescence or shocks.4. MHO arrangements fall into three morphological categories: (1) co-linear MHOs that define the P.A. of onedominant outflow in the region; (2) multiple outflows along distinct P.A.s; and (3) isolated or clustered MHOswhere no clear P.A. can be identified.5. In over half the regions with MHO detections, MHO arrangements and fluorescent H structures trace featurespresent in low-resolution high-velocity CO maps presented in ZHB05, suggesting the CO emission traces acombination of complex dynamical effects that may include expanding H II regions as well as protostellar outflows.6. All but three (Mol 9, 114, & 143) of our 26 target regions contain entries in the WISE
Catalog of Galactic H II Regions (Anderson et al. 2014); however, the majority of these are radio quiet (Q) sources thought to be eithermassive objects in a pre-UC H II region phase, or intermediate-mass star-forming regions. In only four casesdoes a source lie near the center of a collimated MHO outflow, and in each of these cases, the source is clusteredwith other possible driving sources.7. We identify candidate driving sources that fit WISE
Class 0/I YSO criteria (Koenig & Leisawitz 2014; Fischeret al. 2016) and/or are listed as YSOs in the RMS catalog for 26 out of the 36 outflows we distinguish acrossour target regions.8. Only 3 of the 36 outflows ( ∼ II regions; the remaining driving sourcesappear to be younger objects. This suggests that the jet phase shuts off shortly after the YSO has begun toionize it surroundings. Future high-resolution observations of the candidate UC H II regions, particularly radiorecombination line data, would be particularly useful in establishing the evolutionary status of these objects.This research is based on observations obtained with the Apache Point Observatory 3.5-meter telescope, whichis owned and operated by the Astrophysical Research Consortium. We particularly thank the 3.5-meter ObservingSpecialists and Al Harper for assistance in acquiring the data, as well as Michael Medford, who performed the originalNICFPS data reduction. This research has made use of SAOImage DS9, developed by the Smithsonian AstrophysicalObservatory; data products from the Wide-field Infrared Survey Explorer, which is a joint project of the University ofCalifornia, Los Angeles, and the Jet Propulsion Laboratory/California Institute of Technology, funded by the NationalAeronautics and Space Administration; and data products from the Midcourse Space Experiment. Processing ofMidcourse Space Experiment data was funded by the Ballistic Missile Defense Organization with additional supportfrom NASA Office of Space Science. This research has also made use of the NASA/ IPAC Infrared Science Archive,which is operated by the Jet Propulsion Laboratory, California Institute of Technology, under contract with theNational Aeronautics and Space Administration. GW-C was funded in part through NASA’s Illinois Space Grant4Consortium, and the authors gratefully acknowledge support from the Brinson Foundation grant in aid of astrophysicsresearch at the Adler Planetarium. KA thanks Jamie Riggs for help in developing the near-infrared continuumsubtraction procedure, and GW-C thanks Geza Gyuk for assistance converting Table 3 to machine-readableformat. Facilities:
ARC, WISE, MSX
Software:
IRAF, SAOImage DS9, Aladin APPENDIX A. INDIVIDUAL REGIONS: RESULTS AND DISCUSSIONFigures 1 - 20 present images for all targets with MHO detections, with the exception of Mol 160 and Mol 121, whichwere included in previous papers (WSS12; WAS13). For each region, we present (a) a 3-color rgb image that combinescontinuum-subtracted H µ m (blue), continuum-subtracted H µ m (red), and an average of the continuum-subtracted H µ m and H µ m images (green); and (b) a continuum-subtracted H µ m greyscale imagewith MHO numbers and regions (magenta) indicating the apertures used to compute fluxes listed in Table 3. Thergb images include positions of WISE
Class 0/I candidates (labelled yellow circles indicating the resolution of
WISE at 22 µ m), which were identified using the criteria presented in § II region); and entries in WISE
Catalog of Galactic H II Regions (purple boxes labelled according to type: C, G, K, orQ).
IRAS source error ellipses (green) are included on the greyscale images. Maps of the CO outflows for all of theregions discussed below, except Mol 10, were presented in Figure 1 of ZHB05. CO maps of Mol 10 are presented inZhang et al. (2007). We refer the reader to VDR10 for further discussion of regions marked with an asterisk belowand in Tables 2 & 4. A.1.
IRAS 00117+6412 (Mol 2)
The brightest H emission towards this target is due to fluorescence from a PDR centered on the IRAS sourceposition and C-type H II region, G118.964+01.893 (Figures 1a & b). The CO outflow of ZHB05 shows N-S bipolarity.The blueshifted emission peaks at the position of the IRAS source and the redshifted emission peaks ∼ ′′ to thesouth. There is a steep drop-off in emission to the north and east, consistent with the location of G118.964+01.893 atthe eastern border of the molecular cloud.Palau et al. (2010; hereafter, PSB10) identified three intermediate-mass YSOs in this region. One can be associatedwith G118.964+01.893 (which they identify as a UC H II region). Two others are associated with millimeter sources,MM1 & MM2 (MM1 has multiple components). MM1 is located just west of the IRAS error ellipse ( α (2000) =00 h m s , δ (2000) = 64 ◦ ′ ′′ ) and MM2 is located ∼ ′′ to the south ( α (2000) = 00 h m s , δ (2000) =64 ◦ ′ ′′ ). PSB10 estimate the star powering the UC H II region to be ∼ ∼ ⊙ . MM1 is reported tobe a Class 0/I source embedded in a ∼ ⊙ dust core with estimated luminosity of 400-600 L ⊙ . PSB10 mapped a COoutflow along a NE-SW direction, centered on MM1, using CO J=2 → O maser emission, but not centimeter or near-infrared emission. PSB10 noted that MM2 appears to be a ∼ ⊙ Class 0 object, but curiously lacked CO outflow emission.It seems likely that MM1 is the driving source of MHOs 2968A & B to the NE of this source, particularly sincethis is the direction of the CO outflow emission. We suggest that MM2 may drive the H outflow defined by thestring of MHO 2967 knots along a P.A. ∼ ◦ to the south of the H II region; however, we identify additionalClass I candidates (J001427.00+642819.3, J001425.05+642822.4, J001423.45+642824.9) and one Class 0 candidate(J001422.48+642836.8) that can’t be ruled out as driving sources, given the dispersion and morphology of the MHOknots. It is not clear whether these MHOs trace a single outflow and position angle. It is possible that PSB10 did notdetect an outflow associated with MM2 because of the E-W orientation of the outflow traced by the MHOs and a lackof molecular material eastward of the UC H II region.A.2. IRAS 00420+5530 (Mol 3) ∗ We identify three Class I candidates (J004458.06+554656.7, J004457.30+554718.1, J004451.03+554639.9) and oneClass 0 candidate (J004500.80+554627.0) in this region (Figures 2a & b). Four of the MHOs (2900-2903) werepreviously discovered by VDR10. One of these (MHO 2902) lies along a PDR that is probably associated with the
HOs toward HMOs Right Ascension (J2000) D e c li na t i on ( J ) C J001423.45+642824.9J001425.05+642822.4J001427.00+642819.3 J001422.48+642836.8
Right Ascension (J2000) D e c li na t i on ( J ) Figure 1.
Mol 2 (a) rgb image and (b) greyscale image, with labels as described in § A. IRAS source, which is coincident with J004457.30+554718. MHO 2902 has a very low H µ m/2.25- µ m flux ratioof 2.9, so, at the very least, the PDR is likely to contribute to the flux caught by the aperture. A candidate H II region(G122.002-07.084) lies near a ridge of fluorescent emission in the southwest quadrant of the field. The CO high-velocitygas mapped by ZHB05 has a complex morphology with multiple peaks.MHOs appear to lie along at least three distinct position angles in this region. The bow-shaped knot MHO 2903 ap-pears to connect to J004457.30+554718.1 via a faint bridge of H emission along a P.A. of ∼ ◦ . J004457.30+554718.16coincides with VDR10 source “D”, H O masers, and a VLA source (Palla et al. 1991; Molinari et al. 2002, hereafterMTR02). The faint chain of knots (MHOs 2971-2974, 2976) along a P.A. of ∼ -80 ◦ appears to align with Class I can-didate J004458.06+554656.7 (VDR10 source “B”), which is also associated with MM 2 (MTR02) and a mid-infraredsource at α (2000) = 00 h m . s , δ (2000) = 55 ◦ ′ . ′′ that was identified using the MIRLIN camera (Ressler etal. 1994) on NASA’s 3-m Infrared Telescope Facility (IRTF) on Mauna Kea (J. O’Linger-Luscusk, private communi-cation). H O masers are located between MHOs 2971 & 2973 (Harju et al. 1998). Although the bright knot (MHO2901) appears to be associated with J004458.06+554656.7, it is not colinear with the fainter knots and its relationshipto a specific outflow is unclear. Contours associated with overlapping red- and blue-shifted CO emission peaks extendin a general east-west direction roughly 15-30 ′′ south of the IRAS source (ZHB05) consistent with the orientation ofthe MHO chain. MHOs 2969, 2970, 2900, and 2975 are approximately colinear with J004457.30+554718.1 along aP.A. of ∼ ◦ . A.3. IRAS 05137+3919 (Mol 8) ∗ We identify substructure in two outflows previously reported by VDR10 (Figures 3a & b). The outflow along a P.A.of ∼ ◦ is defined by the bright, complex bow-shaped features 1002 & 1003, which are approximately equidistantfrom RMS YSO G168.0627+00.8221. As suggested by VDR10, our 2.12 µ m image confirms that the jet driving thisoutflow may be precessing. Although the component of MHO 1003 furthest from the RMS YSO (1003 2) lies alonga P.A. of ∼ ◦ , the brighter, closer, component, MHO 1003, suggests a P.A. of ∼ ◦ . MHOs 1002 & 1003 are thebrightest MHOs in this region, and follow the position angle of the CO outflow identified by ZHB05. Another outflowalong a P.A. of ∼ -20 ◦ is defined by the MHO 1004 substructures 1004 2 & 1004 3. The morphology of the remainingMHO 1004 components is complex and it is not clear whether they (and MHO 1020) are associated with either outflow.The two outflows intersect at the position of the RMS YSO / Class I candidate J051713.74+392219.6, which is alsocoincident with MM 1 (MTR02), the K sources VDR10 denote as “A” and “B”, and a mid-infrared source detectedwith MIRLIN (J. O’Linger-Luscusk, private communication, unpublished data). The fluxes derived from the MIRLINobservations (F(12.5 µ m) = 4.8 Jy; F(20.8 µ m) = 11.5 Jy; F(24.5 µ m) = 27.6 Jy) rise steeply in the mid-infrared andare comparable to WISE (F(12 µ m) = 4.4 Jy; F(22 µ m) = 18.6 Jy)and MSX (F(12 µ m) = 4.6 Jy; F(21 µ m) = 13.7Jy) fluxes at similar wavelengths. Using the distance (11.5 kpc) and luminosity (2.25 × L ⊙ ) derived from modelingthe SED of this source (Molinari et al. 2008; VDR10), the total H (2.12 µ m) luminosity, (L . ), calculated fromsumming the MHO fluxes in Table 3 and assuming no extinction, is 2.99 L ⊙ . Following WAS13, and assuming the2.12 µ m luminosity is 5-10% of the total rovibrational H emission, L H ∼ ⊙ . Since the assumption of noextinction yields a lower limit to the true H luminosity, this places the Mol 8 outflows at or above the linear fit toLog(L H ) vs. Log(L bol ) for high-mass YSOs presented in Caratti o Garatti (2015, Fig. 9).A.4. IRAS 05168+3634 (Mol 9) ∗ We identify nine Class I candidates, one Class 0 candidate (J052023.40+363745.9), and four sources that sat-isfy both Class 0 & Class I color criteria (J052023.04+363813.0, J052022.03+363756.5, J052010.31+363743.9, &J052010.76+363635.0) in this region (Figures 4a & b). VDR10 found no MHOs near the
IRAS source position,but we note that the low-resolution CO outflow mapped by ZHB05 is centered near J052022.03+363756.5 and a densecore (BGPSv2 G170.661-00.249) identified by the Bolocam Galactic Plane Survey (BGPS v2.1: Ginsburg et al. 2013),not on the
IRAS source. Whereas the CO outflow of ZHB05 lies along a P.A. of ∼ ◦ , the bright bow-shaped MHO1055G lies along a P.A. of ∼ ◦ from J052022.03+363756.5. MHOs 1055 A, C, & E lie along a P.A. of ∼ ◦ . It ispossible that J052022.03+363756.5 is the source of two outflows that produce the large-scale CO morphology, but thisis unclear. Three faint MHOs (1055B, D, & F) lie to the southwest of the IRAS source and one to northwest (MHO1056), but their associations are also unclear.A.5.
IRAS 05274+3345 (Mol 10) ∗ VDR10 present a detailed background of this region, which contains multiple signs of star formation. We identifyfive
ALLWISE sources in this region that satisfy Class I color criteria; two of these also satisfy Class 0 color criteria(J053049.21+334818.4, J053049.01+334746.7). The RMS YSO candidate G174.1974-00.0763 (VDR10 source ‘A’) liesclose to the center of the
IRAS error ellipse and is the brightest infrared source in this field (Figures 5a & b). At leastthree distinct outflows were identified from near-infrared observations (Chen et al. 2005) and via multiple spectrallines using the Submillimeter Array (Zhang et al. 2007). Chen et al. (2005) identified 28 MHOs in this region, which
HOs toward HMOs Right Ascension (J2000) D e c li na t i on ( J ) C J004500.80+554627.0 J004451.03+554639.9J004458.06+554656.7 J004457.30+554718.1
Right Ascension (J2000) D e c li na t i on ( J ) Figure 2.
Mol 3 (a) rgb image and (b) greyscale image, with labels as described in § A. were not entered in the on-line MHO catalog (Davis et al. 2010). Several of these objects lie along three axes theyidentified as the “short”, “middle”, and “long” jets. The three outflows A, B, and C, identified by Zhang et al. (2007)along P.A.s=5 ◦ , 35 ◦ & -60 ◦ , respectively, intersect in the vicinity of the the hot cores they refer to as MM-1 andMM-2. These cores lie approximately at the center of a triangle defined by MHOs 1008, 1009, & 1010 (Figure 5b).8 Right Ascension (J2000) D e c li na t i on ( J ) J051717.01+392145.3J051712.02+392133.9J051713.74+392219.6 Q Right Ascension (J2000) D e c li na t i on ( J ) Figure 3.
Mol 8 (a) rgb image and (b) greyscale image, with labels as described in § A. G´omez-Ruiz et al. (2016) identified several methanol masers at 44 GHz in this region, which are clustered towardsMHOs 1007 & 1008, as well as between MHOs 1008, 1009, & 1010.
HOs toward HMOs Right Ascension (J2000) D e c li na t i on ( J ) J052024.51+363814.6J052024.07+363801.3J052023.04+363813.0 J052010.76+363635.0J052022.03+363756.5 J052011.01+363642.6J052019.62+363622.8J052019.63+363744.6 J052014.45+363704.4J052016.43+363718.7J052023.40+363745.9 J052010.31+363743.9
Right Ascension (J2000) D e c li na t i on ( J ) Figure 4.
Mol 9 (a) rgb image and (b) greyscale image, with labels as described in § A. Based on our 2.12- µ m image (Figure 5b), we can make the following associations: MHO 1005 corresponds to thefeature VDR10 identify as ‘1’ and Chen et al. (2005) associate with a feature they refer to as the ‘short jet’ (see Table4, Mol 10 Flow 1). Similarly, MHOs 1006, 1007, 1008, 1009, 1010, & 1011, correspond to VDR10 features 2, 3, 4, 5, 6,& 7, respectively. Zhang et al. (2007) outflow ‘A’ (Chen et al. 2005 ‘middle jet’) appears as a faint bridge of emissionconnecting MHOs 1009 and 1011, and possibly also MHO 1059 (Figure 5b and Table 4, Mol 10 Flow 2). The ‘longjet’ identified by Chen et al. (2005), along a P.A. of ∼ -60 ◦ , connects MHOs 1057, 1007, and possibly 1060 (Figure5b) along a line slightly south of MM-1 and MM-2 (see Table 4, Mol 10 Flow 3). Although it is tempting to associate0Zhang et al. (2007) outflow ‘B’ with the ‘short jet’ detected by Chen et al. (2005), VDR10, and the present study, wenote that outflow ‘B’ lies along a P.A. ∼ ◦ , while the jet associated with MHO 1005 lies along a P.A. of ∼ ◦ , sothese features may not be tracing the same outflow. Outflow ‘C’ lies along the same P.A. as the long jet. Althoughthis outflow may be associated with MM-1/MM-2, there are several near-infrared point sources (Figure 5a) betweenthese sources and Class I candidate J053046.98+334748.3 that are viable driving source candidates, as is the RMSsource, which is the probable driving source of the large-scale CO outflow mapped by Hunter et al. (1995). It is notclear whether MHO 1060 is associated with this outflow, but it lies along the same P.A. of -60 ◦ .The bow-shaped feature MHO 1006 lies directly west of the RMS source, along a P.A. of -90 ◦ , and is likely driven bythis source (Mol 10 Flow 4). MHO 1006 has the lowest 2.12/2.25 flux ratio of the MHOs we identified in this region andmay be dominated by fluorescent emission from a compact PDR associated with with the RMS YSO/ Q-type objectG174.1974-00.0763, which is in the WISE
Catalog of Galactic H II Regions (Anderson et al. 2014). The associationsof MHOs 1008, 1010 & 1058 with outflows in this region is unclear.A.6.
IRAS 05345+3157 (Mol 11) ∗ The complex arrangements of MHOs clearly indicate multiple outflows in this region (Chen et al. 1999; Chen et al.2003; VDR10). We identify ten
ALLWISE sources that fit Class I color criteria, four of which also fit Class 0 criteria(J053753.90+320015.7, J053752.99+315934.8, J053752.11+320020.0, J053751.45+320021.5). There are at least twodistinct epochs of star-formation (Figures 6a & b): (1) an infrared cluster that is centered on the
IRAS position andis enveloped in a PDR (with no Class 0/I associations); and (2) younger objects to the northeast and northwest ofthe PDR, as indicated by the MHOs, Class 0/I candidates, and seven dense cores (Lee et al. 2011). Lee et al. (2011)suggested that two of the dense cores (Cores 1 & 3) are forming massive protostars. The low-resolution CO map ofZHB05 shows the molecular outflow to be centered at least 30 ′′ to the northeast of the IRAS source, and elongated ina general ESE - WNW direction, with blueshifted outflow gas in the direction of the MHO 1061 knots.The Class I candidate, J053752.03+320003.9, is coincident with Core 3. It is equidistant from the bright bow-shapedfeatures MHO 1015 and 1015 2, which define an outflow along a position angle of 64 ◦ (Table 4, Mol 11 Flow 1). VDR10identified a source they refer to as ‘B’ at the southwest end of MHO 1015 as the possible driving source of this outflow,but our observations suggest J053752.03+320003.9 is the better candidate. The linear chain of knots MHO 1061 A-F(Table 4, Mol 11 Flow 2) also intersect Core 3 and may connect with the MHO 1063 knots to the southeast at aposition angle of -72 ◦ , but this is unclear. There are several WISE
Class I candidates in the vicinity of the MHO 1061knots that are also viable candidates. VDR10 suggested an outflow along a position angle of -49 ◦ (Table 4, Mol 11Flow 3) connecting features we identify with the MHO 1018 and 1016 complexes. Their candidate driving source (‘A’) coincides with a bright ‘orange’ point source on our rgb image (Figure 6A), which lies at the center of this outflow.The Class 0/I candidate, J053752.99+315934.8 (coincident with Core 1), lies at the northwestern end of MHO 1062A(Table 4, Mol 11 Flow 4). MHO 1062A is the second brightest MHO in this region. Although it aligns with the faintknots MHO 1062 B & C to the northwest, it is unclear whether these are part of this outflow. The remaining MHOscannot be clearly linked to distinct outflows. MHO 1019 lies to the southwest of the infrared cluster and may beexcited by a source at the edge of the PDR.A.7. IRAS 05373+2349 (Mol 12) ∗ Except for MHO 751, all of the MHOs in this region were previously detected (VDR10; Khanzadyan et al. 2011).We identify six
ALLWISE sources that satisfy Class I color criteria and two that satisfy Class 0 (J054020.76+235031.0,J054026.46+235222.0) color criteria. The CO outflow mapped by ZHB05 is slightly elongated along a position angle of ∼ ◦ about the IRAS source position. The Class I candidate J054024.79+235048.0, RMS YSO candidate G183.7203-03.6647, and Q-type H II region G183.720-03.665 are positionally coincident near the center of the IRAS error ellipse(Figures 7a & b).Our observations suggest the presence of at least four outflows, as well as isolated knots not clearly connected to anyoutflows in this region. MHOs defining two of these outflows (Table 4, Mol 12 Flow 1 & Mol 12 Flow 3) intersect atthe position of the
IRAS source. Mol 12 Flow 1 is defined by the faint MHO 738 knots along a P.A. of ∼ ◦ , similarto the large-scale CO outflow. The faint knot in the northeast, MHO 742A, lies along this position angle and may bepart of this outflow, but the brighter knots, MHOs 742B & C, lie along a distinctly different position angle of ∼ ◦ .Potential driving sources for this outflow (Table 4, Mol 12 Flow 4) include the Class I candidate J054024.95+235220.6or the nearby Class 0 candidate J054026.46+235222.0. The faint emission knot to the west, MHO 737, may be partof this outflow. Mol 12 Flow 3 joins MHO 739 and MHO 744B along a P.A. of ∼ ◦ . HOs toward HMOs Right Ascension (J2000) D e c li na t i on ( J ) Q J053049.21+334818.4J053049.01+334746.7 J053042.24+334834.6J053050.52+334803.5 J053046.98+334748.3
Right Ascension (J2000) D e c li na t i on ( J ) Figure 5.
Mol 10 (a) rgb image and (b) greyscale image, with labels as described in § A. Mol 12 Flow 2 is defined by the S-shaped series of MHOs along a position angle of ∼ -10 ◦ , which stretches fromMHO 744A to MHO 740A, and includes the MHO 734 knots and MHO 751. Based on the arrangements of theseMHOs, we suggest that Class I candidate J054024.79+235048.0 drives this outflow. This source is coincident withthe brighter of two mid-infrared sources identified by MIRLIN (J. O’Linger-Luscusk, private communication). Thedifferences in mid-infrared fluxes derived from the high-resolution MIRLIN observations (F(12.5 µ m) = 4.19, 1.37 Jy;F(20.8 µ m) = 7.48, 4.79 Jy; F(24.5 µ m) = 11.38, 8.98 Jy) , compared with MSX (F(12 µ m) = 4.65 Jy; F(21 µ m) =12.27 Jy) and WISE (F(12 µ m) = 6.0 Jy; F(22 µ m) = 20.7 Jy) fluxes, suggest that multiple sources contribute to2 Right Ascension (J2000) D e c li na t i on ( J ) J053742.17+320047.4J053742.85+320043.1J053753.90+320015.7 J053744.84+320036.8J053753.49+315958.4J053752.11+320020.0 J053751.45+320021.5J053752.03+320003.9J053752.99+315934.8J053752.17+315925.1 C Right Ascension (J2000) D e c li na t i on ( J ) Figure 6.
Mol 11 (a) rgb image and (b) greyscale image, with labels as described in § A. the mid- and far-infrared luminosity in this region. The remote MHO 735 nearly coincides with Class I candidate,J054019.59+235202.5, but since this is an isolated knot, it is not possible to identify an outflow.A.8. IRAS 06056+2131 (Mol 15)
The arrangement of MHOs in this region closely mirrors the complex morphology of the high-velocity CO emissionmapped by ZHB05, which in turn clearly indicates there are multiple outflows (Figures 8a & b). We identify nine
HOs toward HMOs Right Ascension (J2000) D e c li na t i on ( J ) J054019.59+235202.5J054024.95+235220.6J054020.46+235143.5J054021.78+235102.3J054024.79+235048.0J054024.23+235054.6J054026.46+235222.0 J054020.76+235031.0 Q Right Ascension (J2000) D e c li na t i on ( J ) Figure 7.
Mol 12 (a) rgb image and (b) greyscale image, with labels as described in § A. Class I candidates, two Class 0/I candidates (J060838.48+213043.8, J060842.88+213118.7), and one Class 0 candi-date (J060836.97+213048.8). The western peak of the blueshifted CO emission of ZHB05 is centered on the
IRAS source position, which is coincident with Class I candidate J060840.45+213102.0, RMS YSO G189.0307+00.7821,and Q-type H II region G189.030+00.780. The eastern blueshifted CO peak is centered ∼ ′′ south of Class I4candidate, J060846.72+213144.0, which is coincident with RMS YSO G189.0323+00.8092 and Q-type H II regionG189.032+00.809. The redshifted CO emission of ZHB05 displays a U-shaped morphology that roughly traces theMHO 1216, 1217, and 1218 complexes. Both H II regions lie near dense cores identified by BGPS. Mol 15 Flow 1lies along a position angle of ∼ -35 ◦ , including the MHOs in the 1216 group. This outflow is likely driven by RMSYSO G189.0307+00.7821/ Class I candidate J060840.45+213102.0. MHOs 1217A-C lie along a position angle of ∼ ◦ degrees centered north of G189.0307+00.7821/ J060840.45+213102.0, and the MHO 1218 complex may be associatedwith an outflow produced by RMS YSO G189.0323+00.8092/ Class I candidate J060846.72+213144.0, but the com-plex arrangement of these MHOs makes it impossible to link these to specific outflows. Two other Class I candidates(J060843.63+213150.7, J060843.08+213147.2) are also potential driving sources.A.9. IRAS 06584-0852 (Mol 28) ∗ Most of the H emission in this region is due to fluorescence, some of which may be associated with Q-type H II region G221.955-01.993 (Figures 9a & b). Interestingly, the morphology of the fluorescent emission closely parallels thecomplex CO high-velocity emission identified by ZHB05. VDR10 detected no MHOs in this region; however, we detectthree isolated knots. MHO 3139 lies directly to the northwest of fluorescent H that coincides with overlapping blue-and redshifted CO emission detected by ZHB05. MHO 3140 is coincident with Class I candidate, J070051.00-085629.8(RMS YSO G221.9605-01.9926), and a double mid-infrared source identified by MIRLIN (O’Linger-Luscusk, privatecommunication). The MIRLIN emission (F(12.5 µ m) = 5.27, 1.16 Jy; F(17.9 µ m) = 9.98, 1.10 Jy; F(20.8 µ m) = 10.46,1.38 Jy; F(24.5 µ m) = 11.32, < IRAS 19368+2239 (Mol 108)
This region contains multiple signposts of star formation (Figures 10a & b), including three Q-type H II regions,a RMS source identified as an H II region (G058.4670+00.4360B), a RMS YSO (G058.4670+004360A), and twelve44-GHz masers (G´omez-Ruiz et al. 2016). The CO outflow mapped by ZHB05 is complex and multi-lobed, suggestingmultiple outflows in this region, with most of the high-velocity emission located north of the IRAS position (andRMS sources). We identified eight Class I candidates, two of which are positionally coincident with the RMS H II region (J193857.17+224624.5) and RMS YSO (J193856.89+224632.2). We detected a chain of four MHOs (Mol108 Flow 1), along a position angle of ∼ ◦ , located north of the RMS YSO, but colinear with Class I candidateJ193859.37+224656.0, which clearly shows multiple near-infrared components (see Figure 10a).A.11. IRAS 19374+2352 (Mol 109) ∗ VDR10 detected three MHOs in this region (2600 - 2602). Two of these (2601 & 2602) are located along theperiphery of the
IRAS error ellipse, just south of a PDR associated with G059.612+00.917, a grouped (G-type) H II region (Figures 11a & b). Known (K-type) H II region G059.602+00.911, four RMS objects catalogued as H II regions,and a dense core detected by the APEX Telescope Large Area Survey of the Galaxy (ATLASGAL: Schuller et al.2009) are clustered near the center of the CO outflow mapped by ZHB05, which lies to the southeast of the IRAS position. G´omez-Ruiz et al. (2016) detected two 44-GHz methanol masers just northeast of MHO 2600.We identified three Class I candidates and three additional faint MHOs toward this target. Class I candidateJ193934.64+235948.3 is positionally coincident with the ATLASGAL core, as well as an H II region catalogued in boththe RMS survey and WISE catalog of galactic H II regions (Lumsden et al. 2013; Anderson et al. 2014). This source isparticularly interesting since it exhibits “anomalous” H emission, where the 2.12- µ m/2.25- µ m ratio is less than one.We note that WAS13 detected such emission toward a deeply embedded source (DES: Yao et al. 2000) in Mol 121. TheDES is thought to be a massive YSO driving a very young outflow. It is tempting to associate J193934.64+235948.3with an outflow connecting MHOs 2600 -2602 along a P.A. of ∼ -40 ◦ , but the faint chain of MHOs that extend tothe southwest of MHO 2600 along a P.A. of ∼ ◦ calls into question this interpretation. The CO outflow of ZHB05shows multiple peaks, suggesting more than one outflow in this region. Faint MHO 2628 may be associated with ClassI candidate J193933.43+235836.2, at the southern end of the field.A.12. IRAS 19388+2357 (Mol 110) ∗ All three of the MHOs in this region (2613 - 2615) were previously identified by VDR10. The MHOs, RMS YSOG059.8329+00.6729, and two 44-GHz methanol masers (G´omez-Ruiz et al. 2016) are coincident with Class I candidate
HOs toward HMOs Right Ascension (J2000) D e c li na t i on ( J ) J060846.72+213144.0 J060837.29+213003.5J060843.63+213150.7 J060838.66+213013.5 J060836.97+213048.8J060844.88+213045.0 J060843.08+213147.2 J060837.68+213038.0J060837.47+213108.9J060838.48+213043.8J060842.88+213118.7J060840.45+213102.0
Q Q
Right Ascension (J2000) D e c li na t i on ( J ) Figure 8.
Mol 15 (a) rgb image and (b) greyscale image, with labels as described in § A. J194059.39+240443.9, to within the resolution of
WISE at 22 µ m (Figures 12a & b). MHOs 2614 & 2615 have low2.12- µ m/2.25- µ m flux ratios, suggesting these features are dominated by fluorescent emission; however, MHO 2613has a flux ratio of 5.4, lower than typical values associated with C-type shocked emission, but higher than typicalvalues for either fluorescent or J-type shocked emission. Although MHO 2613 is roughly elongated in the direction ofthe RMS YSO, the complex morphology of the H emission in this region makes association with an outflow tenuous.Furthermore, the peak of the high-velocity CO emission mapped by ZHB05, which shows no hint of bipolarity, lies tothe south of J194059.39+240443.9, closer to the center of the Q-type H II region G059.829+00.671. The CO emission6 Right Ascension (J2000) D e c li na t i on ( J ) Q J070051.00-085629.8
Right Ascension (J2000) D e c li na t i on ( J ) Figure 9.
Mol 28 (a) rgb image and (b) greyscale image, with labels as described in § A. may trace an outflow driven by a yet-to-be-identified source in this region, or it may trace the dynamics of an expandingH II region/PDR. A.13. IRAS 20050+2720 (Mol 114) ∗ Bachiller et al. (1995) discovered an extremely high-velocity multipolar CO outflow in this region. The CO outflowmap of ZHB05 likewise is oriented roughly E-W and is centered to the north of the
IRAS position. VDR10 identified
HOs toward HMOs Right Ascension (J2000) D e c li na t i on ( J ) Q QQ
J193854.25+224522.0J193856.54+224546.3J193857.27+224544.4J193859.37+224656.0J193859.78+224639.7 J193859.01+224644.4J193856.89+224632.2J193857.17+224624.5
Right Ascension (J2000) D e c li na t i on ( J ) Figure 10.
Mol 108 (a) rgb image and (b) greyscale image, with labels as described in § A. several MHOs, including a jet-like feature extending to the southeast of their candidate driving sources, ‘C’ and ‘F’.Our images (Figures 13a & b) reveal more components to the jet, which appears curved (Mol 114 Flow 1). VDR10sources ‘C’ and ‘F’ lie close to a 44-GH maser (G´omez-Ruiz et al. 2016), which is located between MHOs 2608 &2608 6. Although the jet defined by the MHO 2608 group to the southeast of the candidate driving sources lies alonga P.A. of ∼ -87 ◦ , the direction of the jet to the northwest, defined by the MHO 2609 group, lies along a P.A. of ∼ -72 ◦ . This curved jet is likely associated with the CO outflow along a P.A. of ∼ -77 ◦ , denoted “A” by Bachiller et al.(1995: Figure 3).8 Right Ascension (J2000) D e c li na t i on ( J ) GK J193933.43+235836.2J193937.03+235947.9 J193934.64+235948.3
Right Ascension (J2000) D e c li na t i on ( J ) Figure 11.
Mol 109 (a) rgb image and (b) greyscale image, with labels as described in § A. HOs toward HMOs Right Ascension (J2000) D e c li na t i on ( J ) Q J194059.39+240443.9
Right Ascension (J2000) D e c li na t i on ( J ) Figure 12.
Mol 110 (a) rgb image and (b) greyscale image, with labels as described in § A. Although the bright
WISE
Class I candidate, J200706.50+272850.3 (coincident with VDR10 source ‘A’ and RMSYSO G065.7798-02.6121) appears to be the main contributor the the
IRAS flux, this source(s) lies ∼ ′′ to the southof the MHOs that define Flow 1, making it an unlikely driving source candidate. We agree that VDR10 source ‘C’ or‘F’ is more likely to drive the jet, and we note that the energetic parameters calculated by ZHB05 for the high-velocity0CO emission (also located north of the IRAS position) do not suggest a particularly massive outflow. The bolometricluminosity of this outflow (3.88 × L ⊙ ) is the lowest of all the outflows in the ZHB05 study. There are also severalisolated groups of MHOs in this region, which cannot be clearly linked to driving sources, and many YSO candidatesthat may be contributing to different outflows. Right Ascension (J2000) D e c li na t i on ( J ) J200708.63+273031.4 J200700.36+272942.9J200703.21+273004.2J200712.06+272857.2 J200704.92+272748.9J200701.92+272914.9J200709.41+272824.1 J200706.08+272811.0J200706.83+272814.6J200707.73+272819.7J200708.33+272845.9J200705.15+272855.3J200706.50+272850.3
Right Ascension (J2000) D e c li na t i on ( J ) Figure 13.
Mol 114 (a) rgb image and (b) greyscale image, with labels as described in § A. HOs toward HMOs
IRAS 20278+3521 (Mol 125)
Most of the H emission in this region is due to a PDR associated with the Q-type WISE source, G075.155-02.087,which is positionally coincident with the
IRAS source position (Figures 14a & b). A linear arrangement of four faintMHOs along a position angle of ∼ ◦ defines Mol 125 Flow 1, but the axis is offset 10 ′′ to the south of the IRAS source and no known objects within the mapped field can be identified as potential driving sources. We note that thecenter of the CO outflow identified by ZHB05 also lies about 10 ′′ southwest of the IRAS source; however, the positionaldiscrepancy is well within the ∼ ′′ resolution of the CO observations, and the CO emission shows no evidence ofbipolarity, while the MHOs form a linear chain in the plane of the sky. Right Ascension (J2000) D e c li na t i on ( J ) Q J202949.13+353045.7
Right Ascension (J2000) D e c li na t i on ( J ) Figure 14.
Mol 125 (a) rgb image and (b) greyscale image, with labels as described in § A. IRAS 20286+4105 (Mol 126) ∗ Most of the H emission in this region traces fluorescence whose morphology suggests multiple PDRs (Figures 15a &b). The CO outflow mapped by ZHB05 is elongated to the west (and slightly north) of the IRAS source position, in thedirection of extended fluorescent emission. VDR10 identified four YSOs in this region, which they labeled A-D. Source‘A’ coincides with the position of G079.8749+01.1821, listed as a H II region in the RMS catalog ; source ‘C’ coincideswith the WISE
Class I candidate, J203029.51+411558.6; and source ‘D’ lies at the center of an arc that defines thesouthernmost PDR in our images. J203029.51+411558.6, and two 44-GHz masers ∼ ′′ to the southwest (G´omez-Ruizet al. 2016), lie along the rim of the PDR associated with G079.8749+01.1821. It is of interest to note that there arethree spots of anomalous H emission in this region. One of these spots coincides with J203029.51+411558.6 (‘C’),which VDR10 noted was embedded in strong nebulosity. J203029.51+411558.6 also lies at the center of the ZHB05CO outflow.VDR10 suggested the bright emission feature they identify as ‘2’ (MHO 961) is driven by source ‘B’, which lies directlybetween G079.8749+01.1821 and MHO 961. In our images, MHO 961 has a curious “goldfish”-shaped morphologythat points back toward J203029.51+411558.6 (‘C’), suggesting J203029.51+411558.6 is the likely source of MHO 961as well as the CO outflow (Mol 126 Flow 1). J203029.51+411558.6 may also be the source of MHO 960, which appearsto connect to a curving bridge of emission that points back toward this source; however, this is unclear due to thepreponderance of fluorescent emission. MHOs 962 & 963 cannot be linked clearly to sources in this region.A.16. IRAS 21307+5049 (Mol 136) ∗ MHO 882 (detected by VDR10) has a very low 2.12 µ m/ 2.25 µ m flux ratio of 1.1, calling into question the natureof this object. VDR10 noted it lies just ∼ ′′ of a highly-reddened YSO they identify as ‘A’, which is coincidentwith RMS YSO G094.2615-00.4116 (Class I candidate J213230.61+510216.1). VDR10 identified ‘A’ with a cometarynebula that opens to the northwest. High-resolution ( ∼ ′′ ) CO observations, obtained by Fontani et al. (2004) atthe Owens Valley Radio Observatory (OVRO), suggest the RMS YSO (VDR10 ‘A’) is the source of a compact COoutflow. Our continuum-subtracted H µ m images indicate a bipolar nebula with an hourglass shape centeredroughly 16 ′′ to the northeast of the YSO, close to the IRAS position and coincident, within positional accuracy, withthe
WISE
C-type H II region, G094.263-00.414 (Figures 16a & b). The multi-peaked CO outflow mapped by ZHB05 issimilar in direction (NW-SE) and extent to the bipolar nebula, which suggests the fluorescent H emission may tracethe periphery of a bipolar cavity produced by the CO outflow.A.17. IRAS 22172+5549 (Mol 143) ∗ VDR10 noted that this is a known H II region; however, Molinari et al. (1998) did not find radio emission associatedwith the IRAS source and it does not appear in the
WISE
Catalog of Galactic H II regions (Anderson et al. 2014).Molinari et al. (2002) suggested that the O star HD211883, situated ∼ ′ north of a complex ridge of 3.6 cm emission,is the source of the ionization front. Our images (Figures 17a & b) indicate a PDR with ‘pillar’ morphology, suggestingthe source of the H II region lies to the northwest of our imaged region, consistent with this interpretation. ThreeRMS YSOs (G102.8051-00.7184A, B, & C) are located near the apex of the pillar, roughly 20 ′′ north of the IRAS position. MTR02 identified a dense core, via 1.3 and 3 mm continuum observations, that peaks close to the positionof the southernmost RMS YSO, G102.8051-00.7184B.ZHB05 detected multi-lobed CO emission in this region, suggesting more than one outflow. This is also evident inthe ∼ ′′ CO map shown in Figure 14a of Fontani et al. (2004), whose higher-resolution ( ∼ ′′ ) CO map (Figure14c), obtained at OVRO, indicates a very compact ( ∼ ′′ ) north-south outflow centered on the position of RMS YSOG102.8051-00.7184A ( ∼ ′′ northeast of G102.8051-00.7184B). G102.8051-00.7184A & B are coincident with WISE
Class I candidate, J221909.42+560501.2.We identify three distinct jets along position angles ∼
10, 40, & -52 ◦ (Mol 143 Flow 1, 2, & 3, respectively), whichintersect at J221909.42+560501.2. G102.8051-00.7184A is the best candidate driving source for the jet along P.A. ∼ ◦ , which we identify with the compact N-S outflow of Fontani et al. (2004). G102.8051-00.7184A may also drive a jetalong P.A. ∼ ◦ , but this is more difficult to distinguish due to the orientation of A & B. G102.8051-00.7184B likelydrives the jet along P.A. ∼ ◦ . We note that the the high-velocity CO emission contours seen in the single-antennamaps of ZHB05 and Fontani et al. (2004) are consistent with outflows along position angles of 40 & -52 ◦ . HOs toward HMOs Right Ascension (J2000) D e c li na t i on ( J ) C J203029.51+411558.6
Right Ascension (J2000) D e c li na t i on ( J )
963 960961962
Figure 15.
Mol 126 (a) rgb image and (b) greyscale image, with labels as described in § A. A.18.
IRAS 22305+5803 (Mol 148) ∗ We identified eight Class I candidates in this region. VDR10 found three clumpy emission features directly north ofthe
IRAS source position, which coincides with the object we identify as RMS YSO G105.5072+00.2294 and
WISE
Class I candidate J223223.87+581859.7 (Figures 18a & b). The RMS YSO also coincides with the source VDR10identify as ‘A’. The emission features are prominent in Figure 18b; however, they appear to be contaminated byfluorescent emission likely produced by a PDR associated with the Q-type object, G105.509+00.230. The objects4
Right Ascension (J2000) D e c li na t i on ( J ) J213230.61+510216.1 C Right Ascension (J2000) D e c li na t i on ( J ) Figure 16.
Mol 136 (a) rgb image and (b) greyscale image, with labels as described in § A. VDR10 identify as ‘B’ and ‘C’ lie directly north of J223223.87+581859.7, towards the nebulous ‘white’ emission in
HOs toward HMOs Right Ascension (J2000) D e c li na t i on ( J ) J221908.00+560411.1J221909.42+560501.2
Right Ascension (J2000) D e c li na t i on ( J ) Figure 17.
Mol 143 (a) rgb image and (b) greyscale image, with labels as described in § A. Figure 18a. The MHOs we discovered in this region lie well outside of the image presented in Figure A48 of VDR10.MHOs 2777D-G lie along a NE-SW P.A. of ∼ ◦ from the RMS YSO, similar in direction to the CO outflowmapped by ZHB05 (Mol 148 Flow 1). MHOs 2777A-C lie along a P.A. of ∼ ◦ , centered on WISE
Class I candidateJ223219.41+581750.7 (Mol 148 Flow 2).6
Right Ascension (J2000) D e c li na t i on ( J ) Q J223230.29+582034.7J223233.04+582004.4 J223223.19+582027.3 J223219.41+581750.7J223232.47+581936.6 J223219.95+581802.5J223220.24+581817.8J223223.87+581859.7
Right Ascension (J2000) D e c li na t i on ( J ) Figure 18.
Mol 148 (a) rgb image and (b) greyscale image, with labels as described in § A. A.19.
IRAS 22506+5944 (Mol 151)
In this region, we identify a spectacular, compact jet that culminates in the bow-shaped MHOs 2278 A & B(Figures 19a & b). The jet is centered on RMS YSO, G108.5955+00.4935B (Mol 151 Flow 1). Another RMS YSO(G108.5955+00.4935A) is centered on the compact PDR just north of G108.5955+00.4935B and the jet. The location ofG108.5955+00.4935B and its outflow on the periphery of the PDR is suggestive of triggered star formation, warrantingfurther observations exploring the kinematics of this region. G´omez-Ruiz et al. (2016) discovered six 44-GHz masersin this region, all of which lie south of the jet axis. One of these masers is coincident with MHO 2778G. The proximityof this MHO to another RMS YSO (G108.5955+00.4935C) is suggestive of a possible outflow associated with this
HOs toward HMOs Right Ascension (J2000) D e c li na t i on ( J ) Q J225242.60+600041.5
Right Ascension (J2000) D e c li na t i on ( J ) Figure 19.
Mol 151 (a) rgb image and (b) greyscale image, with labels as described in § A. source. The curved chain of MHOs 2779A-D is roughly centered on WISE
Class I candidate, J225242.60+600041.5,the likely driving source (Mol 151 Flow 2). We note that the extent of the outflows in this region are comparable insize to the resolution of the CO outflow map of ZHB05, precluding any meaningful comparison of morphology.A.20.
IRAS 23314+6033 (Mol 158)
The CO outflow mapped by ZHB05 in this region shows no hint of bipolarity. Both lobes peak at the westernedge of the
IRAS error ellipse, near the position of RMS H II region G113.6041-00.6161 and WISE
Class I candidate,8
Right Ascension (J2000) D e c li na t i on ( J ) G J233346.53+605025.9 J233342.73+605025.4
Right Ascension (J2000) D e c li na t i on ( J ) Figure 20.
Mol 158 (a) rgb image and (b) greyscale image, with labels as described in § A. J233342.73+605025.4 (Figures 20a & b). These sources lie at the intersection of ridges of filamentary fluorescentemission. G113.6041-00.6161 is listed as a G-type (grouped) H II region in the WISE
Catalog of Galactic H II HOs toward HMOs
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