George S. Rossano

Near-infrared [Fe II] emission of M82 supernova remnants : implications for tracing the supernova content of galaxies

Near-infrared [Fe II] and Paβ spectra of two young supernova remnants and one H II region within the central 15 kpc of M 82 are reported. Comparison of these spectra reveal a [Fe II]/Paβ ratio similar to that observed in Galactic supernova remnants and H II regions, and show that the [Fe II] background emission in M 82 has local maxima at the position of the supernova remnants observed in the radio continuum.

The 1.0-1.3 micron spectrum of LkH-alpha 101

Spectrophotometry of resolution greater than 300 of LkHα 101 from 0.8 to 1.35 μm is presented. Spectroscopic observations at moderate or high spectral resolution now exist for this source from the mid optical to 2.5 μm. The emission lines present in this data set are Paβ, Paγ, and Paδ; He I λ10830; Fe II λλ9907, 10174, 10490, 10501, 10863, and 11126; [Fe II] λ12567; and O I λλ11287 and 13164.

Surface Heating from Remote Sensing of the Hypervelocity Entry of the NASA GENESIS Sample Return Capsule

An instrumented aircraft and ground-based observing campaign was mounted to measure the radiation from the hypervelocity (11.0 km/s) reentry of the Genesis Sample Return Capsule prior to landing on the Utah Test and Training Range on September 08, 2004. The goal was to validate predictions of surface heating, the physical conditions in the shock layer, and the amount and nature of gaseous and solid ablation products as a function of altitude. This was the first hypervelocity reentry of a NASA spacecraft since the Apollo era. Estimates of anticipated emissions were made. Erroneous pointing instructions prevented us from acquiring spectroscopic data, but staring instruments measured broadband photometric and acoustic information. A surface-averaged brightness temperature was derived as a function of altitude. From this, we conclude that the observed optical emissions were consistent with most of the emitted light originating from a gray body continuum, but with a surface averaged temperature of 570 K less than our estimate from the predicted heat flux. Also, the surface remained warm longer than expected. We surmise that this is on account of conduction into the heat shield material, ablative cooling, and finite-rate wall catalycity. Preparations are underway to observe a second hypervelocity reentry (12.8 km/s) when the Stardust Sample Return Capsule returns to land at U.T.T.R. on January 15, 2006.

Near-Infrared and Ultraviolet Spectrophotometry of Symbiotic Novae

ABSTRACTIn this paper we present an atlas of near-infrared spectrophotometry of symbiotic novae and reportresults from nearly contemporaneous IUE observations. The data cover RT Ser, AG Peg, V1016 Cyg,V1329 Cyg, HM Sge, and Pu Vul, most of the known symbiotic novae that are observable from thenorthern hemisphere. Emission-line strengths for both spectral regions are tabulated. Extinction valuesare derived from He II j1640 in the UV and He II j10124 in the infrared. Spectral types are determinedfor the cool giant component using infrared absorption features. The extinction and apparent J (1.25 km)magnitude measured from the spectrophotometry are combined with the known relation between spec-tral type and absolute magnitude to derive distances for each system.Subject headings: binaries: symbiotic ¨ infrared: stars ¨ novae, cataclysmic variables 1 . INTRODUCTION Symbiotic novae represent a subclass of symbiotic starsthatundergoasingle,orveryinfrequent,nova-likeoutburst(Viotti 1988). This subclass originally contained only sevenobjects: AG Peg, RT Ser, RR Tel, V1016 Cyg, V1329 Cyg(\HBV 475), HM Sge, and AS 239 (\V2110 Oph) (Allen1980a). PU Vul was identi—ed later, and recent studies(Bragaglia et al. 1995; Ivison & Seaquist 1995) have addedthree additional members, while the classi—cation of V2110Oph has been questioned (Murset & Nussbaumer 1994,hereafter MN). Symbiotic novae diƒer from classical novaein several respects: (1) In symbiotic novae the companionstar is a late-type giant rather than a dwarf. This results inmuch smaller outburst amplitudes since the preoutburstoptical and infrared brightness is determined by the giant.However, the total energy associated with the outburst of asymbiotic nova may signi—cantly exceed that of a classicalnova. (2) Symbiotic systems are widely separated ratherthan close binaries, with orbital periods that vary from twoto several dozen years, instead of a few days. As such, theemission-line region that results from the transfer of massfrom the late-type star to the hot companion arises from astellarwindratherthanRochelobeoverNow.Moreover,theemission-line region does not envelope both stars, evenduring outburst. (3) The increase to maximum brightnessusuallytakesseveralmonths,notthefewdayscharacteristicof classical novae. (4) Similarly, the return to preoutburstbrightness is also much slower, with emission lines per-sistingfordecadesinsteadofmonthsoryears.Because the emission-line regions associated with theoutburst of a symbiotic nova evolve over such long periods,itisimportanttoprovideaseriesofobservations that mon-

The near-infrared Fe II forbidden lines of MWC 922

Spectrophotometry from 0.8-1,6 μm of the peculiar emission-line object and strong [Fe II] source MWC 922 is presented. Detections or useful upper limits are given for nine [Fe II] features between 1.25 and 1.54 μm which are used to test the accuracy of theoretically derived transition probabilities. The measured intensity ratios of all the lines were found to agree with the values predicted from the transition probabilities of Nussbaumer and Storey to within 30%. The derived electron density and temperature for the gas producing the [Fe II] emission are 10 5 cm -3 and 5000 K

An IRAS search for dust in globular clusters

The IRAS Point-Source Catalog, Small-Scale Structure Catalog, and HCON1 Sky Brightness Images were searched for sources of emission that were spatially coincident with any of 144 globular clusters. The purpose was to measure or place upper limits on the amount of thermal dust emission from the clusters, which would lead to estimates and upper limits to the mass of intraglobular dust. Sputtering by hot gas in the galactic halo can destroy dust grains and thus possibly explain the absence of dust in glogular clusters. 84 refs.

Near-infrared spectroscopy of the planetary nebula NGC 6572

Spectroscopy of the PN NGC 6572 in the wavelength region 0.77-1.33 micron is presented. The measurement of line fluxes in regions of high telluric absorption is discussed, and an error in the wavelengths of forbidden P II reported in the literature is pointed out. The NGC 6572 continuum is well-matched by bound-free, free-free, and two-photon components at a temperature of 10,500 K. No significant contribution from the exciting star or hot dust is seen. The primary generation mechanism for the O I lines is fluorescent excitation by the stellar continuum. A sulfur abundance of 6.53 is derived, and N(P+)/N(S+) = 0.11 is found. This is much greater than the solar value and is probably due to the underabundance of S. 45 refs.

The 0.46-1.3 micron spectrum of the planetary nebula BD +30 deg 3639

Optical and infrared spectrophotometry of the planetary nebula BD +30°3639 is presented. A number of previously unobserved emission lines redward of 1.1 μm are identified, most of which are permitted lines of carbon. The carbon lines, which are the most prevalent features in the spectrum, originate in a more compact region than do the nebular lines. The C III lines are formed predominantly by recombination, but their relative strengths are modified by continuum fluorescence and by optical depth effects in both resonance and nonresonance transitions.

Detection of the O I 11287 Å line in the Seyfert 1 galaxy I Zw 1

This paper reports a detection of the infrared 11287 A transition of neutral oxygen in the Seyfert 1 galaxy I Zw 1. The observed strength of the feature is 6.5 x 10 to the -14th erg/sq cm sec. When this value is compared to the flux of O I 8446A measured by Persson and McGregor (1985), the ratio of the photon fluxes is unity, to within the measurement uncertainties. This is a direct confirmation that the broad permitted O I lines observed in Seyfert 1 galaxies and quasars arise through fluorescent excitation by Lyman Beta. 17 refs.

MID-INFRARED SPECTROSCOPY OF PERSISTENT LEONID TRAINS

The first infrared spectroscopy in the 3–13 micron region has been obtained of several persistent Leonid meteor trains with two different instrument types, one at a desert ground-based site and the other on-board a high-flying aircraft. The spectra exhibit common structures assigned to enhanced emissions of warm CH4, CO2, CO and H2O, which may originate from heated trace air compounds or materials created in the wake of the meteor. This is the first time that any of these molecules has been observed in the spectra of persistent trains. Hence, the mid-IR observations offer a new perspective on the physical processes that occur in the path of the meteor at some time after the meteor itself has passed by. Continuum emission is observed also, but its origin has not yet been established. No 10 micron dust emission feature has been observed.