VVV Survey Microlensing Events in the Galactic Center Region
María Gabriela Navarro, Dante Minniti, Rodrigo Contreras Ramos
DDraft version November 5, 2018
Preprint typeset using L A TEX style AASTeX6 v. 1.0
VVV SURVEY MICROLENSING EVENTS IN THE GALACTIC CENTER REGION
Mar´ıa Gabriela Navarro , Dante Minniti , Rodrigo Contreras Ramos Depto. de Cs. F´ısicas, Facultad de Ciencias Exactas, Universidad Andr´es Bello, Av. Fernandez Concha 700, Las Condes, Santiago, Chile. Millennium Institute of Astrophysics, Av. Vicuna Mackenna 4860, 782-0436, Santiago, Chile. Vatican Observatory, V00120 Vatican City State, Italy. Instituto de Astrof´ısica, Pontificia Universidad Cat´olica de Chile, Av. Vicuna Mackenna 4860, 782-0436 Macul, Santiago, Chile.
ABSTRACTWe search for microlensing events in the highly reddened areas surrounding the Galactic center usingthe near-IR observations with the VISTA Variables in the V´ıa L´actea Survey (VVV). We report thediscovery of 182 new microlensing events, based on observations acquired between the years 2010 and2015. We present the color-magnitude diagrams of the microlensing sources for the VVV tiles b332,b333, and b334, which were independently analyzed, and show good qualitative agreement amongstthemselves. We detect an excess of microlensing events in the central tile b333 in comparison with theother two tiles, suggesting that the microlensing optical depth keeps rising all the way to the Galacticcenter. We derive the Einstein radius crossing time for all of the observed events. The observedevent timescales range from t E = 5 to 200 days. The resulting timescale distribution shows a meantimescale of < t E > = 30 .
91 days for the complete sample ( N = 182 events), and < t E > = 29 . N = 96 RC events). There are 20 longtimescale events ( t E ≥
100 days) that suggests the presence of massive lenses (black holes) or disk-diskevent. This work demonstrates that the VVV Survey is a powerful tool to detect intermediate/longtimescale microlensing events in highly reddened areas, and it enables a number of future applications,from analyzing individual events to computing the statistics for the inner Galactic mass and kinematicdistributions, in aid of future ground- and space-based experiments.
Keywords:
Gravitational lensing: microlensing — Galaxy: bulge — Galaxy: structure INTRODUCTIONThe idea proposed by Paczy´nski (1986), based on the works of Einstein (1916, 1936), that microlensing eventscan be detected by measuring the intensity variations of millions of stars was highly successful. In particular, themain groups dedicated to observe the Galactic bulge like the Massive Astrophysical Compact Halo Objects (MACHO;Alcock et al. 1993), the Optical Gravitational Lensing Experiment (OGLE; Udalski et al. 1993), the MicrolensingObservations in Astrophysics (MOA; Bond et al. 2001), the Exprience pour la Recherche d?Objets Sombres (EROS;Aubourg et al. 1993), the Disk Unseen Objects (DUO; Alard et al. 1995a), the Wide-field Infrared Survey Explorer(WiSE; Shvartzvald & Maoz 2012) and the Korea Microlensing Telescope Network (KMTNet; Kim et al. 2010, Kim etal. 2017), discovered thousands of events to date in the bulge. These are all optical surveys, and necessarily monitoredthe regions with low relative extinctions toward the bulge. The innermost regions close to the Galactic center, whichare not only severely crowded, but also heavily obscured by interstellar dust, have remained hidden for microlensingup to now. However, these regions are very interesting because this is where we expect to find the highest number ofmicrolensing events and presumably also the largest microlensing optical depth because of the high density of stars(Gould 1995).Fortunately, in the near-IR, we can penetrate through the gas and dust in this region in order to detect microlensingevents. The first such near-IR study was successfully carried out recently by Shvartzvald et al. (2017), who foundfive highly extinguished microlensing events between 1 and 2 degrees from the Galactic center. The
VISTA Variablesin the V´ıa L´actea Survey (VVV; Minniti et al. 2010) is a near-IR variability Survey that scans 560 square degreesin the inner Milky Way using the
Visible and Infrared Survey Telescope for Astronomy (VISTA), a 4 m telescopelocated at ESO’s Cerro Paranal Observatory in Chile. The main goal of the VVV survey is to create a 3D map ofthe inner Galaxy, mainly using the K s -band to search for variable stars as distance indicators and tracers of stellar a r X i v : . [ a s t r o - ph . S R ] D ec populations. At the same time, the VVV survey is an excellent tool to detect microlensing events. Even though theVVV survey cadence (nightly at best) is inadequate to routinely detect objects associated with short timescales thatshould be numerous in the Galactic center region (Gould 1995), this is sufficient to perform a census of microlensingevents toward the central most part of the Galaxy.The analysis of a complete a sample of microlensing events in the central part of the Galaxy has many applications,ranging from the study of the most interesting isolated events: for example, the ones that have long durations whichstatistically favor more massive lenses to large statistical studies of Galactic structure and evolution. For the latter,the distribution of timescales can be useful to test the different possible scenarios for the structure and evolution of theinner part of the Galaxy (Calchi Novati et al. 2008, Sumi et al. 2013). We note that as the timescale is a degeneratecombination of lens mass, and lens-source relative parallax and proper motion, it is necessary to include Galacticmodels related to specific populations. Moreover, the study of the event rate can be extremely useful to optimizethe observational campaign for the Wide Field Infrared Space Telescope (WFIRST) (Green et al. 2012, Spergel et al.2015), and as complementary to the pioneering work published by Shvartzvald et al. (2017).The purpose of this paper is to present the first large sample of microlensing events in the Galactic center area usingthe VVV data. In this work, we use the simple model of lensing by an isolated point mass (PSPL). We derive theEinstein radius crossing time distribution of the observed events. We also characterize the microlensing sources usingthe available near-IR photometry. For the future, we propose to extend the spatial and temporal range of the sampleto compare the observed distributions with the most recent Galactic models and to analyze selected events.In section 2 we describe the data used in this research and the procedure that was carried out to detect the mi-crolensing events. The characterization of the final sample is shown in section 3. Finally, the conclusions are presentedin section 4. THE SEARCH FOR MICROLENSING AROUND THE GALACTIC CENTERThe VISTA telescope is equipped with the
Wide-field VISTA InfraRed Camera (VIRCAM; Emerson & Sutherland(2010)) containing 67 million pixels (16 chips of 2048x2048 pixels). The Field of View (FoV) is 1 . deg , which iscalled a “tile”. The entire VVV observations comprise 196 tiles in the bulge and 152 in the disk area (Saito et al. 2012).The VVV observational schedule includes single-epoch photometry in ZY JHK s bands and variability campaign in K s band (Minniti et al. 2010). In this work, we focus on the innermost tiles of the VVV (b332, b333 and b334), wherethe crowding is so severe that PSF photometry is mandatory. Accordingly, the photometric reduction of each detectorwas carried out using the DAOPHOT II/ALLSTAR package (Stetson 1987), and the catalogs made at the CambridgeAstronomical Survey Unit (CASU) with the VIRCAM pipeline v1.3 (Irwin et al. 2004) were used to calibrate ourphotometry into the VISTA system by means of a simple magnitude shift using several thousands stars in common(see Contreras Ramos et al. 2017). We specifically applied this procedure separately on each detector of the tiles b332,b333, and b334 located within 1 . o ≥ l ≥ − . o and 0 . o ≥ b ≥ − . o in the Galactic bulge. We detected a totalof approximately 14 × point sources in these three tiles, for which multi-epoch magnitudes in the K s -band weremeasured. The reduced data included about 100 epochs spanning six seasons (2010-2015) of observations.The search of events was performed by means of a new reduction code specially developed for microlensing detec-tions. Contrary to the classical variable star detection, our approach has been optimized to keep those events showinga few deviating points with a transient magnification of the apparent brightness, which would be likely rejected usingthe classical variability indexes. This procedure delivers a quality index for each light curve related to how similarit is with a microlensing curve. It is then necessary to cull the sample by selecting the curves with higher qualityindices for subsequent visual inspection, but before that it is crucial to perform the fitting procedure using the sim-plest model, assuming a point source and a point lens (PSPL) (Refsdal 1964). Where F = F s A ( u ( t )), with F beingthe observed and F s the catalog source flux, for their non-blended fits. The amplification A ( u ( t )) and the angulardistance between the lens and the source projected on the plane of the lens in Einstein radii units u ( t ) can be written as A ( u ( t )) = u + 2 u √ u + 4 (1) u ( t ) = (cid:115) u + (cid:18) t − t t E (cid:19) (2)The standard microlensing model delivers the u related to the impact parameter and thus with the amplitude ofthe light curve, the time of maximum amplification t and the Einstein radius crossing time t E . The fitting procedurewas performed twice, also including the blending parameter f bl which we expect to be non-negligible in this region, inthis case F = F s [ f bl ( A ( u ) −
1) + 1]. Figure 1 shows five examples of our near-IR microlensing light curve fits. In all
Figure 1 . Sample microlensing light curves and best fits. The first four events indicated in the upper panel are located inthe Red Clump. The fits with (blue line) and without blending (magenta) are indistinguishable and overlap with each other,yielding similar parameters. cases, consistent results were found using both procedures.At the visual inspection stage, the following requirements were applied for the curve to be qualified as a microlensingevent:1. Constant baseline;2. Baseline covering more than one season;3. At least four points with 4 σ above the baseline;4. At least one data point in the rising and falling microlensing light curve;5. Symmetry during the event;6. Timescales within an acceptable range to avoid confusions with long period variable stars; and7. Good fit to single microlensing curve.The final sample was divided in two groups. The 182 first quality microlensing events that satisfy all the requirementsmentioned above (Table 1), and a second quality list with events showing an evident microlensing light curve, butnot meeting all the requirements listed above. We also notice that the last condition eliminated a few good candidatebinary events. Hereafter, we will only deal with the high-quality sample, and the individual study of these other casesis deferred for the future.The magnitude range of the majority of bulge source stars is 11 < K s < .
5, and their near-IR colors (2 < J − K s < K s <
16, where there are N = 78 sources in tile b333 versus N = 45 on the average of tiles b332 andb334. This is also seen if we count only the RC sources, where the counts are N = 37 for b333 versus N = 30 for the Figure 2 . Spatial distribution of the new microlensing events (red squares) around the Galactic center, overlaid on the extinctionmap of Gonzalez et al. (2012). The duplicate events in the overlapping areas have been accounted for. average of the other two tiles, but this is not statistically significant. The most straightforward implication is that themicrolensing optical depth keeps rising all the way to the Galactic center, but further observations are necessary toconfirm this.As an external check on the fidelity of our results, we performed the microlensing search separately in the threeVVV tiles b332, b333, and b334. There is a small observed overlap region between these tiles, and although thearea of the superposition is small ( ∼ t lessthan 7 days, and difference between the baseline magnitudes less than 0.15 mag. We detected six repetitions in total,and in all these cases we obtained consistent results: the positions RA and DEC repeat to better than 1 arcsec, the K s -band magnitudes repeat to better than 0.08 mag, the times of maxima repeat to better than 3 days, and thetimescales repeat to better than 15% in all cases but two (these are two short timescale sources that have a timescaledifference of 25%). For these objects, the fitting procedure using the standard microlensing model was recalculatedusing the data by joining both independent light curves in order to obtain more precise parameters.Other checks were made, such as analyzing the timescale versus amplitude relation (Figure 3). This showed ahomogeneous distribution of the amplitudes and no trends with the timescales, as expected. Also, we fitted knownmicrolensing events from OGLE and MOA in order to confirm that our fitting routines yield the correct parameters. CHARACTERIZATION OF THE MICROLENSING EVENTSThe most important parameter that the standard microlensing model fit provides is the Einstein radius crossing time t E which is related to the mass of the lens. The precise value of the lens mass can be constrained with the timescaleobtained from the light curve; relative distances between the observer; lens and source; and transverse velocity.RC giants are core-He burning giants that have known mean luminosities and can be used as distance indicators.Therefore, selecting RC stars with the correct magnitudes increases the probability that they are located at thebulge distance (e.g. Popowski et al. 2005). We therefore selected a subsample of events consistent with RC by makingmagnitude cuts in the color-magnitude diagrams that follow the direction of the reddening vector (Figure 4). For theseRC sources, we can assume that they are located in the Galactic bulge. The large reddening is evident, especially inthe central most region (tile b333). Moreover, as blending can be severe in the area we analyzed, the sources thatbelong to the RC are brighter and give us more reliable information, reducing the blending problem (Popowski et al.2005, Sumi & Penny 2016). From the color-magnitude diagrams of Figure 4, it is clear that nearly half of the sourcesare located in the RC. As a consistency check, all three tiles investigated independently (b332, b333, and b334) showgood agreement with each other.The majority of the microlensing events in the sample region are expected to be bulge-bulge events and bulge-diskevents (e.g. Gould 1995), but at these latitudes there are also potentially disk-bulge events with the source in the fardisk. Indeed, the foreground contamination by disk-disk events appears to be small, as we observe only half a dozensources with blue-enough colors ( J − K s ≤ .
0) consistent with a foreground main-sequence disk population (Figure 4).
Figure 3 . Left panel: timescale distribution of the complete sample microlensing events (top histogram), compared with that ofthe RC subsample (bottom histogram). The purple and cyan lines are the best Gaussian fits, with the mean positions labelled.Right panel: distribution of the impact parameter u and Einstein radius crossing time t E for the complete sample. With the information provided by the fitting procedure and the color-magnitude diagram, it is impossible to obtainall of the parameters needed to constrain the individual lens masses, except for the cases in which the parallax effectsare evident. As mentioned earlier, special events like parallax events will be analyzed in the future. However, for alarge enough sample like ours, the distribution of timescales gives a global idea of mass distributions and tentativemass ranges that were detected (Figure 3).The shape of the timescale distribution is similar for the total sample and the RC sample. The peak of thetimescale distribution, i.e., the most common value for the Einstein radius crossing time of the complete sample is30 . ± .
08 days, and for the RC sources is 29 . ± .
06 days. The RC sample mean is slightly shorter, but consistentwithin the errors. These mean values correspond to intermediate mass lenses (typical disk/bulge main-sequence stars)under reasonable model assumptions like those of the recent predictions of Wegg et al. (2017). The shape of thetimescale distribution is also consistent with some previous studies in the bulge region (Wyrzykowski et al. 2015).Both distributions follow a symmetric curve in log ( t E ), which is different, for example, from the distribution obtainedby Barry et al. (2011). This is probably due to the lack of short timescale VVV events.Both distributions are similar (Figure 3), ranging from small values suggesting stellar mass objects to long durationevents, which are generally associated with massive objects. Short timescale events with t E ≤
10 days are lacking,and we argue that this is merely an effect of our low sampling efficiency for the short events in comparison with othersurveys like OGLE and MOA that have more frequent sampling and much longer timescale coverage. For example, thefrequent sampling of the observations by Shvartzvald et al. (2017) yield shorter timescale events in the mean (rangingfrom t E = 7 days to 30 days). Their mean timescale, t E = 17 . t E ≥
100 days) that are consistent with the presence of massive objects (in the black hole realm) or disk-disk events.However, as the value of the timescale is degenerate, it is necessary to do a more detailed study of these events, e.g. toinclude parallax in the fitting procedure and to model the inner Galaxy using different initial mass functions. Theseanalyses are proposed for the future and are beyond the scope of this letter.Finally, the observed timescale and magnitude distribution of the detected events can be helpful to optimize theobservational microlensing campaign of the WFIRST (Spergel et al. 2015), and also to predict event rates and com-pleteness. The observed magnitude ranges for the J and K s -bands (12 < J < .
5, and 11 < K s < .
5, respectively),and the color-magnitude diagrams show that the searches are more efficient at longer wavelengths. In fact, most ofthe photometric incompleteness in our sample is given by the lack of deeper J-band observations.
Figure 4 . Near-IR K s vs J − K s color-magnitude diagrams for the VVV tiles 332 (left), 333 (center), and 334 (right). The starsindicate the sources of the sample microlensing events. The stars in green are the microlensing events with RC sources. Themagenta star in the 333 CMD corresponds to the event with J mag above the detection limit. The arrows show the reddeningvector after (Nishiyama et al. 2009). 4. CONCLUSIONSFor the first time, we have detected a large number of microlensing events around the Galactic center using theVVV near-IR photometry. We present the color-magnitude diagrams of the microlensing sources for the VVV tilesb332, b333, and b334, which show good qualitative agreement amongst themselves. There is an apparent excess ofmicrolensing sources in the central tile b333 in comparison with the average of the other two tiles, even though tileb333 is the most reddened and crowded of all.We also presented the timescale distribution of the observed events that ranges from 5 to 200 days. We do notfind significant numbers of events with t E <
10 days, due to our low-detection efficiency for short timescale events.There is, however, a non-negligible number of long timescale events ( t E ≥
100 days), which would be consistent witha population of massive black holes or disk-disk events.This work demonstrates the usefulness of the VVV Survey to detect microlensing events in highly reddened andcrowded areas like the Galactic center region. The present microlensing search covers the three most central VVVtiles, and can, in principle, be extended to adjacent areas that have not yet been studied due to heavy extinction. Suchextended search would produce a complete timescale distribution map of the inner Milky Way bulge and show thedependencies with Galactic latitude and longitude, to complement previous bulge microlensing studies (e.g. Popowskiet al. 2005, Sumi et al. 2013, Wyrzykowski et al. 2015).Our work also indicates that the microlensing optical depth keeps rising all the way to the Galactic center, butfurther observations are necessary to confirm this, and that a microlensing search in this region with the WFIRSTwould be very profitable (Spergel et al. 2015); and our results may be relevant to optimize the observational campaignsfor that and other future surveys.We gratefully acknowledge data from the ESO Public Survey program ID 179.B-2002 taken with the VISTA tele-scope, and products from the Cambridge Astronomical Survey Unit (CASU). Support is provided by the BASALCenter for Astrophysics and Associated Technologies (CATA) through grant PFB-06, and the Ministry for the Econ-omy, Development and Tourism, Programa Iniciativa Cient´ıfica Milenio grant IC120009, awarded to the MillenniumInstitute of Astrophysics (MAS). D.M. acknowledges support from FONDECYT regular grant No. 1170121.REFERENCES
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Table 1 . VVV Survey first quality microlensing events data with their respective positions in equatorial coordinates, baseline K s magnitude, Color and the parameters obtained using the standard microlensing model including the blending ( f bl ). Thelabel RC correspond to the events located in the Red Clump and the O refers to the events that overlap.Tile ID RA DEC K s J − K Amp u t t E f bl Comment (mag) (mag) (MJD) (days) b332 14-26290 265.09996 -31.37107 15.56 3.28 1.47 0.45 56437.69 112.43 1.00 RCb332 14-55860 265.16328 -31.41736 15.72 3.81 6.36 0.11 57243.97 40.78 1.00 RCb332 16-32398 264.84333 -30.69719 15.44 4.31 3.60 0.22 56181.72 21.25 1.00 RCb332 18-36548 265.43515 -30.96762 13.20 5.61 1.48 0.41 55792.95 13.93 1.00b332 18-41105 265.38645 -31.05165 15.34 3.50 1.81 0.14 56478.57 72.58 0.15 RCb332 68-5694 265.48753 -30.75808 15.30 3.70 0.68 0.48 55783.51 10.50 1.00 RCb332 68-14868 265.49243 -30.78767 16.02 3.84 2.21 0.32 56487.96 34.08 1.00 RCb332 68-39711 265.50969 -30.87205 12.51 6.72 1.72 0.38 56484.66 34.32 0.98b332 68-43156 265.48090 -30.92659 16.64 2.76 8.24 0.05 56488.58 43.10 0.54b332 110-61443 265.06127 -30.50046 15.13 3.69 1.07 0.05 56046.39 62.43 1.00 RCb332 110-74031 265.16668 -30.40049 13.26 3.75 0.46 0.46 56552.93 64.47 0.33 RCb332 114-43783 265.32371 -30.07666 14.59 3.65 0.79 0.65 56090.08 29.69 1.00 RCb332 21-40061 264.31254 -30.77783 16.64 2.98 2.39 0.30 56558.71 16.99 1.00b332 23-82719 264.88706 -31.20422 12.96 4.10 1.23 0.48 56895.29 19.22 1.00b332 27-8503 264.90537 -30.87510 13.90 4.75 0.60 0.67 56202.48 12.00 0.55 RC,Ob332 27-15159 264.99483 -30.77833 13.94 4.59 2.02 0.25 56118.66 14.81 1.00 RCb332 27-31227 264.99579 -30.84077 13.13 86.88 0.46 0.84 55799.69 16.49 1.00b332 27-38227 265.03919 -30.80838 13.77 5.26 4.24 0.19 56874.75 40.70 0.96b332 34-1193 264.93179 -31.15614 16.53 2.25 8.34 0.05 55792.34 116.06 0.45b332 34-4022 264.95451 -31.13701 17.03 2.00 0.85 0.19 55783.65 16.44 0.48b332 34-57640 265.02460 -31.25104 16.08 83.92 1.59 0.13 56163.10 56.19 0.28b332 38-16855 265.12081 -30.96135 15.72 84.26 1.07 0.37 56491.21 21.31 0.71b332 44-42130 265.07155 -31.13005 17.27 82.68 7.98 0.09 55799.68 36.05 1.00b332 48-5228 265.23875 -30.75368 16.05 83.94 0.75 0.62 56107.66 29.69 1.00b332 48-81289 265.46393 -30.74961 15.83 3.99 3.87 0.21 57249.02 65.75 1.00 RCb332 51-54921 264.45830 -30.63581 16.77 2.17 1.41 0.05 56135.92 83.84 0.11b332 59-16446 264.73652 -30.09485 15.72 1.84 1.47 0.41 56090.41 10.66 1.00b332 59-26357 264.79947 -30.04314 12.87 2.15 9.87 0.05 56196.62 23.67 0.55 RCb332 66-77202 265.00700 -30.63918 14.98 3.89 0.53 0.81 55812.01 96.44 1.00 RCb332 211-37537 265.29213 -30.44556 11.48 4.16 0.46 0.36 55833.97 12.92 1.00b332 213-59426 264.96048 -29.96142 13.71 2.15 0.33 1.00 56484.12 51.61 0.90 RCb332 213-72294 264.97054 -29.99633 13.12 2.71 0.66 0.71 56149.62 43.19 1.00 RCb332 310-80902 264.98350 -30.33055 16.95 2.33 1.35 0.05 55813.77 113.55 0.10b332 310-100917 265.05852 -30.29863 15.82 84.23 1.78 0.05 56517.63 104.76 0.20b332 312-5320 265.30551 -30.66024 16.36 83.29 6.39 0.05 55787.84 25.27 1.00b332 410-53003 265.00924 -30.19381 14.43 2.94 0.86 0.55 57202.94 72.14 1.00 RCb332 414-8102 265.14228 -29.85276 13.76 2.45 0.39 0.49 56200.05 15.87 0.36 RCb332 414-18576 265.15753 -29.87074 13.66 86.34 1.57 0.09 55812.30 22.84 0.61
Table 1 continued on next page
Table 1 (continued)
Tile ID RA DEC K s J − K Amp u t t E f bl Comment (mag) (mag) (MJD) (days)(mag) (mag) (MJD) (days)
Tile ID RA DEC K s J − K Amp u t t E f bl Comment (mag) (mag) (MJD) (days)(mag) (mag) (MJD) (days) b332 414-69038 265.26596 -29.91121 15.92 3.36 2.42 0.28 56495.48 26.85 1.00b332 511-90196 265.46836 -30.39392 15.24 4.58 1.55 0.33 56062.48 72.79 1.00 RCb332 513-61175 265.06202 -29.82790 16.24 2.33 3.23 0.28 56120.77 116.70 1.00b332 515-19885 265.52832 -30.05048 13.80 2.41 0.70 0.20 55790.66 29.83 0.17 RCb332 610-23832 265.17869 -30.19984 13.64 3.28 0.24 0.31 57271.00 25.02 0.25 RCb332 610-47014 265.21751 -30.22933 13.48 2.85 0.32 1.00 56085.32 6.49 0.95 RCb332 610-78499 265.26797 -30.27310 12.92 3.13 0.65 0.66 56451.52 69.02 1.00 RCb332 610-97533 265.29367 -30.30727 13.22 3.77 0.29 1.00 56059.03 58.48 0.99 RCb332 614-45372 265.35913 -30.03531 12.38 4.11 3.89 0.21 56732.81 91.71 1.00 Ob332 616-24844 265.94883 -30.18384 15.19 2.72 1.35 0.05 57239.33 77.31 0.17 RCb333 12-42539 265.50396 -29.81472 16.76 83.01 1.75 0.40 56124.13 14.24 1.00b333 12-69304 265.52124 -29.88285 14.33 3.72 0.81 0.18 56825.95 76.48 0.16 RCb333 14-55156 266.02807 -30.18754 16.74 83.32 4.38 0.05 56015.03 85.21 1.00b333 23-1263 265.57612 -29.91941 14.86 4.49 7.37 0.05 56036.53 23.22 0.39 RCb333 23-4699 265.66126 -29.81254 13.17 2.71 0.41 0.65 56123.65 21.74 0.48 RCb333 27-90082 265.96369 -29.68600 14.35 5.36 0.80 0.30 57248.76 30.11 0.36 RCb333 211-1492 266.00663 -29.31280 14.73 4.72 4.63 0.05 56038.23 23.05 0.33 RCb333 211-15629 266.08567 -29.24704 12.31 4.71 1.40 0.42 56123.94 28.73 0.90b333 211-17696 266.05926 -29.29131 17.01 4.35 4.11 0.05 56101.05 25.88 1.00b333 213-8425 265.80896 -28.57501 14.13 3.28 3.07 0.11 57251.15 42.03 0.67 RCb333 215-18630 266.33176 -28.90853 14.83 85.15 4.41 0.18 55998.65 23.59 1.00b333 16-86247 265.76515 -29.60036 17.13 82.82 1.64 0.28 56838.36 10.89 1.00b333 21-1306 265.02993 -29.64241 12.73 2.05 1.66 0.37 56037.80 7.73 1.00b333 21-106713 265.21343 -29.75273 15.37 1.50 7.18 0.05 56019.43 125.27 1.00b333 25-1139 265.33053 -29.21758 15.03 1.95 5.17 0.05 56036.98 10.91 1.00b333 25-13345 265.28460 -29.32971 14.17 2.12 6.51 0.05 57279.95 34.81 0.95 RCb333 25-69718 265.43930 -29.32309 15.60 4.25 1.60 0.08 56864.43 111.72 0.22 RCb333 29-89508 265.63252 -29.09897 15.33 4.41 1.96 0.20 56373.39 8.85 0.79 RCb333 110-14235 265.92726 -29.11678 14.80 4.63 1.70 0.39 56024.59 18.96 1.00 RCb333 110-84253 266.00399 -29.24772 12.38 4.87 0.66 0.56 56823.78 5.71 1.00b333 110-103868 266.02570 -29.28402 13.30 5.48 1.16 0.31 55812.12 14.90 1.00b333 513-21168 265.92994 -28.44640 14.04 2.44 3.43 0.14 56833.34 9.94 0.53 RCb333 18-90199 266.33387 -29.88208 14.42 85.57 1.00 0.39 56175.52 13.72 1.00b333 32-17832 265.34470 -29.60216 14.52 85.46 6.09 0.13 56037.96 24.85 1.00b333 32-64434 265.36278 -29.73430 15.41 3.36 1.92 0.28 57170.22 13.98 0.81 RCb333 32-65431 265.42744 -29.64701 13.14 3.39 1.97 0.09 56029.38 18.91 0.72 RCb333 32-75883 265.42179 -29.69092 14.30 3.84 2.41 0.29 56136.14 22.44 0.96 RCb333 34-42751 265.85305 -30.03220 14.46 85.56 1.19 0.05 56474.62 115.65 0.06b333 34-49917 265.94819 -29.92529 16.42 83.49 7.44 0.05 56017.23 147.62 1.00b333 34-81174 265.94033 -30.05182 12.97 4.07 1.01 0.56 56032.42 54.66 1.00b333 36-26139 265.52159 -29.38604 17.23 2.75 2.85 0.17 56038.73 11.96 0.60b333 36-36965 265.58457 -29.33481 14.98 3.71 6.46 0.05 56509.76 27.33 0.71 RC
Table 1 continued on next page Table 1 (continued)
Tile ID RA DEC K s J − K Amp u t t E f bl Comment (mag) (mag) (MJD) (days)(mag) (mag) (MJD) (days)
Tile ID RA DEC K s J − K Amp u t t E f bl Comment (mag) (mag) (MJD) (days)(mag) (mag) (MJD) (days) b333 42-1507 265.35617 -29.53228 11.47 3.51 1.31 0.17 56841.00 22.34 1.00 Ob333 42-4246 265.37832 -29.51096 11.57 3.48 0.60 0.16 56085.67 60.87 0.12b333 44-97159 266.06948 -29.93123 14.02 4.98 0.66 0.05 56893.72 12.66 1.00 RC, Ob333 46-40910 265.71181 -29.17016 14.83 4.46 1.33 0.36 56060.26 51.03 1.00 RCb333 51-33207 265.26581 -29.42843 13.42 3.03 2.60 0.20 56144.52 10.97 0.65 RCb333 53-62793 265.84453 -29.75693 14.23 1.97 0.49 0.61 56417.41 62.10 1.00b333 57-41448 266.02671 -29.42235 13.67 5.70 0.78 0.54 56821.26 14.30 1.00b333 59-11271 265.64080 -28.81314 15.95 3.03 3.10 0.23 57249.42 54.24 1.00b333 62-70519 265.72288 -29.59623 16.97 82.98 5.58 0.12 56019.40 51.48 1.00b333 64-31424 266.18966 -29.86641 14.64 3.59 0.72 0.68 56094.53 13.64 1.00 RCb333 64-49508 266.15813 -29.97755 15.35 84.70 4.62 0.05 56071.79 121.84 0.67b333 64-96023 266.29007 -29.97366 14.67 4.19 5.40 0.14 56184.72 25.38 1.00 RCb333 66-21828 265.78826 -29.34844 16.30 83.68 3.29 0.24 55780.57 86.78 1.00b333 66-52469 265.85955 -29.35649 14.71 4.41 1.69 0.36 56857.92 40.88 1.00 RCb333 68-104841 266.51787 -29.66045 14.31 4.72 4.07 0.05 56506.52 27.79 1.00 RCb333 112-106497 266.65154 -29.47018 14.78 4.29 3.24 0.05 56566.06 29.37 1.00 RCb333 114-13230 266.08843 -28.88644 15.08 4.36 4.14 0.09 56490.79 50.01 0.54 RCb333 114-46792 266.22084 -28.81652 10.72 4.59 1.24 0.46 56811.23 42.69 0.97b333 116-37815 266.66043 -29.21073 13.77 4.58 1.07 0.44 56099.16 10.14 1.00 RCb333 116-79669 266.81518 -29.13610 12.81 4.72 0.22 1.00 56061.13 32.72 0.74b333 310-29281 265.78988 -29.01572 13.91 3.97 0.67 0.16 56151.46 11.15 0.25 RCb333 310-79969 265.80993 -29.16381 13.83 3.82 1.32 0.05 56042.08 12.42 0.39 RCb333 310-96589 265.82793 -29.19609 13.44 4.32 1.55 0.41 56044.91 18.08 1.00b333 312-2696 266.19753 -29.39797 16.01 83.86 3.76 0.05 56010.00 86.72 1.00b333 312-44070 266.28416 -29.41028 12.69 87.31 1.06 0.55 56375.82 12.48 1.00b333 312-62428 266.36750 -29.35349 12.52 6.83 0.95 0.10 56925.41 108.42 0.16b333 314-29796 265.94244 -28.80337 14.66 3.66 0.78 0.64 56384.91 69.60 1.00 RCb333 314-55699 266.06406 -28.72311 15.59 3.89 2.00 0.05 56493.50 13.00 1.00 RCb333 314-77236 266.03154 -28.84794 13.92 3.94 0.21 0.67 56160.58 26.26 0.30 RCb333 316-15279 266.48065 -29.03126 14.83 4.67 0.82 0.05 56189.99 8.04 1.00 RCb333 316-40378 266.53643 -29.03117 13.76 5.29 0.73 0.67 56811.65 61.01 1.00b333 316-90842 266.62655 -29.07436 12.75 5.38 2.38 0.19 56813.44 14.90 0.83b333 316-100780 266.62076 -29.11919 14.58 2.10 1.71 0.41 56125.07 20.65 1.00 RCb333 410-7976 265.84798 -28.85905 11.51 5.12 1.22 0.47 55801.43 29.85 1.00b333 412-26866 266.43900 -29.12995 12.49 5.17 1.49 0.44 57225.16 126.32 1.00b333 414-25228 266.02719 -28.66408 15.22 3.78 3.74 0.05 56525.74 67.09 0.51 RCb333 414-49757 266.09186 -28.65845 13.23 86.78 1.74 0.29 56087.28 32.52 0.70b333 416-65395 266.66200 -28.93446 13.07 86.94 0.57 0.76 56159.63 24.51 1.00b333 515-29074 266.46354 -28.75120 14.39 85.59 1.40 0.44 57276.83 51.74 1.00b333 515-45486 266.51525 -28.73049 13.48 3.26 0.81 0.58 57187.48 43.37 1.00 RCb333 515-49289 266.46807 -28.81187 12.65 4.48 1.33 0.35 57114.57 184.52 1.00b333 610-11467 265.98079 -29.03053 12.35 4.53 0.32 0.89 56514.01 30.38 0.71
Table 1 continued on next page Table 1 (continued)
Tile ID RA DEC K s J − K Amp u t t E f bl Comment (mag) (mag) (MJD) (days)(mag) (mag) (MJD) (days)
Tile ID RA DEC K s J − K Amp u t t E f bl Comment (mag) (mag) (MJD) (days)(mag) (mag) (MJD) (days) b333 610-36012 266.06155 -28.99876 12.33 4.41 0.22 0.80 56417.64 38.71 1.00b333 610-40425 266.08328 -28.98288 13.74 4.28 3.07 0.21 56138.31 13.54 0.96 RCb333 610-50685 266.12013 -28.96453 13.32 4.80 1.84 0.36 56114.15 28.78 1.00b333 612-80860 266.71318 -29.28126 14.95 4.97 1.18 0.50 56035.82 5.69 1.00 RCb333 612-98993 266.67770 -29.40080 12.69 4.45 0.88 0.33 57261.87 37.54 0.42b333 614-70531 266.34156 -28.72281 14.24 4.94 0.47 0.65 56095.26 50.27 0.57 RCb333 614-84336 266.35631 -28.74884 14.35 4.61 6.74 0.05 57260.35 38.69 1.00 RCb333 614-94658 266.41497 -28.69935 12.85 4.16 1.49 0.26 56121.04 6.49 0.97b334 16-74959 266.61660 -28.34858 14.75 5.69 2.39 0.24 56128.88 26.20 0.72 RCb334 21-23644 265.97740 -28.38942 14.50 3.24 1.54 0.42 55820.68 11.43 1.00 RCb334 34-25019 266.68395 -28.78282 14.66 5.83 1.66 0.40 56173.57 64.33 1.00 RCb334 34-82386 266.88664 -28.72094 12.37 6.28 1.67 0.00 55992.50 47.02 0.20b334 36-13718 266.32706 -28.19646 14.46 2.39 3.59 0.17 57251.46 45.42 1.00 RCb334 36-20307 266.40409 -28.10910 13.34 3.78 1.05 0.38 56856.98 15.42 1.00 RCb334 36-83203 266.50899 -28.18965 17.28 2.53 13.40 0.02 56126.77 31.55 0.35b334 38-32772 266.99787 -28.35616 14.26 3.89 0.95 0.00 56009.09 77.89 0.10 RCb334 42-83526 266.34657 -28.42009 14.53 4.08 2.23 0.32 57245.15 58.45 1.00 RCb334 44-14992 266.84899 -28.50806 15.40 84.55 2.56 0.29 56182.30 14.52 1.00b334 44-77077 266.92793 -28.63633 14.24 4.79 0.79 0.26 56837.94 104.58 0.25 RCb334 110-47231 266.84039 -27.93049 15.85 4.14 4.86 0.15 56842.88 9.75 1.00 RCb334 110-81842 266.91081 -27.95946 14.40 4.42 1.12 0.13 56004.80 110.82 0.18 RCb334 112-80046 267.40998 -28.27695 14.39 4.65 2.84 0.27 55807.07 179.63 1.00 RCb334 112-91317 267.39564 -28.33975 11.11 3.79 1.47 0.43 56583.86 33.65 1.00 Ob334 616-64986 267.71918 -27.77335 14.67 3.06 1.38 0.35 56516.10 13.82 1.00 RCb334 14-35957 266.91087 -28.86083 14.89 4.25 1.05 0.00 56266.64 101.01 1.00 RCb334 114-2993 266.95813 -27.59214 14.23 3.81 0.85 0.05 56897.19 24.42 1.00 RC,Ob334 114-34851 266.99985 -27.65723 12.90 5.39 3.97 0.18 56099.08 30.45 1.00b334 114-86000 267.15587 -27.65442 11.40 5.52 0.28 1.00 56559.30 35.94 0.86b334 116-26287 267.55340 -27.87324 13.52 3.85 0.96 0.45 56487.61 5.73 0.71 RCb334 116-34279 267.50475 -27.97748 11.93 0.44 0.53 0.78 56003.36 19.68 1.00b334 116-80676 267.64681 -27.95567 14.34 3.73 5.29 0.15 56158.40 28.41 1.00 RCb334 316-42169 267.36471 -27.86155 16.13 3.56 2.90 0.19 57170.53 16.68 0.73b334 316-51711 267.40790 -27.83484 14.14 4.98 0.70 0.68 56110.12 9.46 1.00 RCb334 316-90309 267.49660 -27.85982 15.09 4.62 1.55 0.20 56190.74 12.02 1.00 RCb334 23-24739 266.51787 -28.66503 13.42 5.56 0.67 0.21 56472.64 167.96 0.17b334 23-41942 266.51526 -28.73046 13.48 3.25 0.75 0.16 57188.50 98.78 0.19 RCb334 25-71070 266.25801 -28.15896 12.57 3.31 0.65 0.71 55806.34 38.26 1.00b334 51-10132 266.06642 -28.21192 15.15 2.34 1.84 0.00 56499.51 17.47 0.15 RCb334 51-56759 266.18724 -28.21185 15.69 2.98 6.96 0.06 56099.35 73.99 0.56b334 51-85618 266.18884 -28.31620 14.30 2.69 2.43 0.29 56139.42 29.41 0.97 RCb334 55-55967 266.40621 -27.87824 14.37 2.81 2.11 0.10 57233.42 35.06 0.49 RCb334 55-58674 266.37368 -27.93529 14.77 2.36 6.44 0.04 56198.53 16.91 0.69 RC
Table 1 continued on next page Table 1 (continued)
Tile ID RA DEC K s J − K Amp u t t E f bl Comment (mag) (mag) (MJD) (days)(mag) (mag) (MJD) (days)