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SIRTF at the AAS: Jan 2003 |
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The following talks and posters featured SIRTF or the research of SIRTF team members.
Presentations on Legacy and GTO programs and ancillary data:Session 6. The GOODS and Those HEROsPoster, Monday, January 6, 2003, 9:20am-6:30pm, Exhibit Hall ABSince this whole session involves talks from the GOODS Legacy team, we have not listed each of them here. Deep Near Infrared Imaging of the NGC 7129 Region: Investigating Low Mass Star Formation in a Young Stellar ClusterR. A. Gutermuth (Univ. of Rochester), S. T. Megeath (Harvard-Smithsonian CfA), J. L. Pipher (Univ. of Rochester), L. E. Allen, P. C. Myers (Harvard-Smithsonian CfA)The NGC 7129 region is an active site of star formation, as shown by Herbig-Haro objects, outflows, dense molecular gas, and several young stars surrounded by bright reflection nebulosity. While published submillimeter and far infrared observations of NGC 7129 characterize the effects of associated massive young stars in this region on the surrounding medium, there has been little examination of the cluster of low mass stars known to exist in the region. We have obtained wide-field (11' x 11') J, H, and Ks band images of NGC 7129 using the FLAMINGOS instrument on the 6.5 meter MMT telescope. We used standard aperture photometry methods to measure the flux of all detected point sources down to 10 sigma detection limits of J = 18.6, H = 18.1, and Ks = 17.3. At a cluster distance of 1 kpc (Racine, 1968) we can detect 1 Myr old, unattenuated 25 Mjup objects. From these data we can establish the mass distribution in this region, allowing us to determine the initial mass function and initial spatial configuration of both stellar and sub-stellar objects. As part of a SIRTF Guaranteed Time Observation program, these data will be combined with SIRTF images of the region to determine the complete 1-24 micron SEDs for each star in the region. The combined ground-based/SIRTF observations will provide unparalleled data on the incidence and properties of protostellar envelopes and protoplanetary disks in young clusters.Formation and Evolution of Planetary Systems: A SIRTF Legacy Science Program Progess ReportD. Soderblom (STScI), M. R. Meyer (Steward Obs., Univ. of Ariz.), Dana Backman (Franklin & Marshall Coll.), S. V. W. Beckwith (STScI), T. Y. Brooke (JPL), J. M. Carpenter (Caltech), M. Cohen (Radio Astron. Lab, U. C. Berkeley), U. Gorti (NASA-Ames), T. Henning (Astrph. Inst. Jena), L. A. Hillenbrand (Caltech), D. Hines (Steward Obs., U. of ARIZ.), D. Hollenbach (NASA-Ames), S. Kim (Steward Obs., U. of ARIZ.), J. Lunine, R. Malhotra (LPL, U. of Ariz.), E. Mamajek, A. Moro-Martin (Steward Obs., U. of ARIZ.), P. Morris (SIRTF Sci. Ctr.), J. Najita (NOAO), D. L. Padgett, J. Stauffer (SIRTF Sci. Ctr.), S. E. Strom (NOAO), D. Watson (U. of Rochester), S. Weidenschilling (Plan. Sci. Inst.), S. Wolf (Caltech), E. Young (Steward Obs., U. of Ariz..)We describe a SIRTF Legacy Science Program to carry out spectrophotometric observations of solar-type stars aimed at (1) defining the timescales over which terrestrial and gas giant planets are built, from measurements diagnostic of dust/gas masses and radial distributions; and (2) establishing the diversity of planetary architectures and the frequency of planetesimal collisions as a function of time through observations of circumstellar debris disks. Together, these observations will provide an astronomical context for understanding whether our solar system -- and its habitable planet -- is a common or a rare circumstance.Here we summary properties of our sample, update the planned observing strategies, report the status of our ancillary observing programs, and describe modelling efforts aimed at interpreting complete spectral energy distributions from 0.3--1300 \mum. More information concerning our program can be found at http://feps.as.arizona.edu. The COMPLETE Survey of Nearby Star-Forming Molecular CloudsJ. Di Francesco (NRC-HIA), A. A. Goodman (Harvard), J. Alves (ESO), H. Arce (Caltech), P. Caselli (Arcetri), M. H. Heyer (UMass), D. Johnstone (NRC-HIA), S. Schnee (Harvard), M. Tafalla (OAN), T. L. Wilson (MPIfR)We report on the preliminary data and ongoing progress of the COMPLETE* Survey of Nearby Star-Forming Molecular Clouds, an international effort to provide the astronomical community with uniform, wide-field observations of molecular line emission, dust continuum emission, and dust extinction across the Ophiuchus, Perseus, and Serpens molecular clouds. Such observations of ~10 square degrees are now only feasible with the recent simultaneous availability of multi-element mapping instruments at various facilities. Extensive data of 12CO and 13CO J = 1-0 rotational transition emission across the 3 clouds will be obtained this winter using the 32-element SEQUOIA array of the Five College Radio Astronomy Observatory (FCRAO). Complementary 850 micron thermal continuum emission from dust within these same regions may be obtained this winter using the 37-element Long-Wave SCUBA array of the James Clerk Maxwell Telescope (JCMT). Dust extinction maps of these regions are being compiled initially using Two-Micron All Sky Survey (2MASS) data. The resulting COMPLETE database, accessible freely to the public through a pilot program of the National Virtual Observatory, will allow for comprehensive studies of the relationships between star formation and the physical conditions within molecular clouds, especially in conjunction with sensitive near- to mid-infrared data of these regions expected from the SIRTF Legacy program ``Cores to Disks" (c2d).(*COMPLETE=CO-ordinated Molecular Probe Line, Thermal Emission, and Extinction) GLIMPSE: Plans for a SIRTF Legacy Program to Survey the Inner Regions of the Milky WayE.B. Churchwell, R. Indebetouw, R.A. Benjamin (U. Wicsonsin-Madison), GLIMPSE TeamGLIMPSE, a SIRTF Legacy Science Program, will be a fully sampled, confusion limited, 4-band near to mid-infrared survey of the inner two-thirds of the Galactic disk with a spatial resolution of ~2". The Infrared Array Camera (IRAC) will be used to image the Galactic plane at 3.6, 4.5, 5.8, and 8.0 microns. The survey will cover Galactic latitude |b|=±1 degrees and longitude |l|=10 degrees to 70 degrees on both sides of Galactic center. The survey area contains the outer ends of the Galactic bar, the Galactic molecular ring, and the inner spiral arms. The GLIMPSE team will process this data to produce a point source catalog and a set of mosaiced images. We summarize our observing strategy, give details on our output data products, and discuss some of the principal science questions that this survey will address.The SIRTF Wide-area InfraRed Extragalactic Survey (SWIRE) --- Exploring the dark side of galaxy evolutionC.K. Xu (Caltech), C. J. Lonsdale (P.I., CalTech), M. Rowan-Robinson (Imperial College, London), H.E. Smith (UCSD), D. Shupe, J. Surace (Caltech), SWIRE TeamSWIRE, the largest SIRTF Legacy program, is a wide-area, imaging survey of infrared galaxies and AGNs. It will survey 7 high-latitude fields, 65 sq. deg. in total, in all 7 SIRTF bands to the 5-sigma sensitivity limits of f(3.6um)=7.3 uJy, f(4.5um)=8.7 uJy, f(5.8um)=27.5 uJy, f(8.0um)=32.5 uJy, f(24um)=0.45 mJy, f(70um)=2.75 mJy, and f(160um)=17.5 mJy. The key scientific goals of SWIRE are to enable fundamental studies of cosmology and galaxy formation in the mid- and far-infrared, for the key redshift range 0.5 < z < 2.5 where much of cosmic evolution has occurred: (1) The evolution of both actively star-forming and passively-evolving galaxies to determine the history of galaxy formation (including the global Star Formation History - SFH), in volumes large enough to place this in the context of cosmic structure formation and galaxy environment. (2) The spatial distribution and clustering of evolved galaxies, starbursts, and AGN, and the evolution of their clustering in the redshift range 0.5 < z < 2.5. (3) The evolutionary relationship between galaxies and AGN, and the contribution of AGN accretion energy to the cosmic backgrounds, relative to that from nucleosynthesis.In order to better define our science goals as well as to aid the survey planning, we have developed sophisticated empirical models for the evolution of infrared galaxies and AGNs. Exploiting a large SED library which covers a very wide wavelength range, these models can predict counts and colors in various wavebands, including the UV, optical, NIR, MIR, FIR, sub-mm, and radio. Comparing these predictions with data taken from available surveys such as IRAS, ISO, SCUBA, and the HST deep surveys in the optical and NIR, the parameters in the models can be tightly constrained. According to these models, the SWIRE survey will be dominated by: (1) more than 100,000 luminous infrared galaxies (Lfir> 10^11 L\sun); up to 10,000 with z> 2. (2) nearly 1 million early-type galaxies; up to 10,000 with z> 2. (3) 26,000 classical AGN, and as many as 130,000 dust-obscured QSO/AGN. Our best-fit model also predicts the following 3-sigma confusion limits: f(3.6um)=0.10 uJy, f(4.5um)=0.19 uJy, f(5.8um)=0.39 uJy, f(8.0um)=0.99 uJy, f(24um)=0.06 mJy, (70um)=6.35 mJy, and f(160um)=82.5 mJy. Accordingly, the SWIRE survey will be confusion limited in the 70um and 160um bands. Investigating the mid-far IR properties of LBGs with the SWIRE Legacy SurveyB. D. Siana, H. E. Smith (UC San Diego/CASS), C. J. Lonsdale (Infrared Processing and Analysis Center), SWIRE TeamA topic of significant current interest is the star formation rate (SFR) in the z=3 Lyman Break Galaxy (LBG) population and their relation to high redshift luminous infrared/submm galaxies and the Cosmic Infrared Background (CIB). Until the launch of SIRTF, star formation in LBGs was inferred from their rest-frame UV and optical data alone. Unfortunately, unknown extinction and star formation histories greatly hinder any SFR determination. With 5\sigma sensitivities at 70\mum, 160\mum, and 20cm, of 2.75 mJy, 17.5 mJy, and 15\muJy respectively, the SIRTF Wide-area InfraRed Extragalactic Survey (SWIRE) may detect the brightest end of the LBG luminosity function. The detection of the radio emission and reprocessed UV in the mid-far IR will allow a more direct determination of LBG SFRs, extinction laws, and their contribution to the CIB. The candidates for SWIRE detection and extinction analysis techniques will be reviewed. This work is supported by NASA-SIRTF Legacy Program funding to UCSD.The BIMA Survey of Embedded Cores in the Perseus Cloud ComplexN.H. Volgenau, L.G. Mundy (U. Maryland), N.J. Evans II (U. Texas), SIRTF c2d Legacy Project TeamWe report on results from a survey of 21 embedded cores in the Perseus Molecular Cloud Complex that has been conducted with observations from the Berkeley-Illinois-Maryland Association (BIMA) interferometer. The survey targets were selected from a database of known ammonia cores and included a range of luminosities and masses. The cores were observed in the 2.7mm continuum and the J=1-0 transitions of 13CO and C18O. Three different configurations of the BIMA array were used, allowing the cores to be mapped with resolutions of 10, 5, and 3 arc-seconds. Observations for the survey were concluded in Summer 2002. The maps have typical noise levels of ~1.2 mJy per 5" beam in the continuum. Line emission is detected in all fields; continuum emission from discrete sources is detected in approximately 70% of the fields. We compare the gas and dust emission to the 2MASS source distribution, as well as the distribution of candidate young sources determined from the 2MASS colors.The BIMA survey is designed to complement the SIRTF Legacy Project ``From Molecular Cores to Planet-Forming Disks,'' which will map four of the nearest large molecular clouds (including Perseus) and 120 known embedded cores. The combined datasets will allow us to investigate many aspects of early stellar evolution, including the distributions of the gas and young stars, the extent of molecular depletion in core environments, and the correlation between velocity structure and the multiplicity of central sources. This research is supported by NASA grant NAG-510611. WIYN/Hydra Spectroscopy of Stars in the Direction of Star Forming Region W51T. L. Laurance (Middle Tennessee State University), H. A. Kobulnicky (University of Wyoming), R. A. Benjamin, E. B. Churchwell (University of Wisconsin-Madison)We have obtained moderate resolution optical spectra (resolving power=4000) in the range of 3500 to 4500 Angstroms towards a sample of stars in the direction of the star forming region W51 located in the plane of the Galaxy. These observations were made using the WIYN 3.5m telescope and Hydra instrument at Kitt Peak, Arizona. Here we present the results of our spectral classifications. These observations will be used to support GLIMPSE, a SIRTF legacy program, which will produce 4-band mid-infrared photometry for several million point sources in the Galactic Plane. In particular, we will use this sample to understand whether these mid-infrared colors can be used to determine the spectral type of ordinary stars.
Presentations by SIRTF EPO:Invisible Universe Online: Designing, Facilitating, and Evaluating an Online Course in AstronomyA. Gauthier (University of Arizona Steward Observatory), J. Keller (LPL, University of Arizona), M. Bennett (ASP), S. Buxner (Fiske Planetarium, University of Colorado), E. DeVore (SETI Institute), T. Slater (University of Arizona Steward Observatory), M. Thaller (JPL)How do online students learn best? Which methods of teaching can be adopted from physical classrooms? What are some strategies for building a collaborative learning community? How can instructors effectively integrate web activities, simulations, and applets into online science courses? What do the online students think?Online course designers are sharing successful ideas, instructional strategies, and challenges related to the online learning environment. We present our evaluation summary of the first offering of Invisible Universe Online: The Search for Astronomical Origins for Teachers (Spring 2002), subsequent changes in course design for the second offering of the course (Fall 2002), and current experiences on how those changes are being implemented. Additionally, we provide samples of the interactive web activities, applets, and simulations used in the class to help promote student active learning. Challenges of computing technology, student adeptness with their computers, and user interface will also be discussed. Invisible Universe Online is delivered via WebCT through the Montana State University National Teacher Enhancement Network (http://btc.montana.edu/). The 15-week course covers the chain of events from the birth of the universe through the formation of galaxies, stars, and planets. The course curriculum focuses on scientific questions, technological challenges, space missions pursuing the search for origins, and career guidance for classroom teaching of astronomy and related concepts. Course participants are in-service science teachers (middle school through high school) from the both the United States and abroad. This course is being developed, evaluated, and offered through the support of SOFIA and SIRTF EPO Programs, two NASA infrared missions associated with the Origins Program. The course provides a platform for investigating distance learning approaches for future SOFIA and SIRTF education efforts.
Other presentations by SIRTF Science Center Staff:Small Groups of Galaxies Associated with the Gravitational Lenses CLASS B1608+656 and CLASS B1600+434C. D. Fassnacht, L. M. Lubin (UC-Davis), G. K. Squires (SIRTF Science Center), A. C. S. Readhead (Caltech)In addition to their usefulness in the determination of cosmological parameters, gravitational lenses may be used as tools to find groups of galaxies that are associated with the primary lensing galaxy. With this new techique, it is possible to find small groups at moderate redshifts, where cosmological dimming and the high density of background galaxies would otherwise make such groups difficult to detect. In this paper we describe the results of a continuing program to find galaxy groups at redshifts between 0.3 and 1.0. Our data suggest that the gravitational lens systems CLASS B1608+656, at z=0.63, and CLASS B1600+434, at z=0.41, are associated with small groups of galaxies. We will describe the photometric, spectroscopic, and morphological properties of the group galaxies. In addition, we will present the overall group properties, and compare these to the properties of local groups of galaxies.HST/STIS Coronagraphic Imaging of the Disk of DM TauriC. Grady (Eureka Scientific, NOAO, and GSFC), B. Woodgate (NASA's GSFC), K. Stapelfeldt (JPL), D. Padgett (SIRTF Science Center), B. Stecklum (Thuringer Landessternwarte Tautenburg, Germany), T. Henning (MPIA, Heidelberg, Germany), V. Grinin (Crimean Astrophysical Observatory), A. Quirrenbach (UCSD), M. Clampin (STScI)Near-IR studies of pre-Main Sequence stars have suggested that by 5 Myr signatures of near-stellar dust become rare, presumably due to clearing of the inner disk, while in some systems by 8 Myr the transition to a debris disk + planetary system may be complete. As part of a study of the evolution of protoplanetary disks, we present broadband optical coronagraphic imagery of the 5 Myr old T Tauri star, DM Tau obtained with HST/STIS. At V>14.3, DM Tau is the faintest object coronagraphically imaged with HST. We detect an asymmetric ring of bright, presumably reflection, nebulosity surrounding the star, with an inner dark oval with radius along its major axis= 2.2" (308 AU). The orientation and inclination for the oval, determined from its minor/major axis ratio, is consistent with the disk major axis and inclination determined from the millimeter. Beyond the dark oval, a bright ring of nebulosity is asymmetrically distributed about the star extending 3.95" (550 AU) along the major axis. We identify the brighter portion of the ring to the NE of the star along the system minor axis as the forward scattering side of the disk.This bright ring drops in surface brightness as r(-2), indicating that we detect material which is flared with respect to the disk midplane. In tandem with the millimeter continuum data for DM Tau (Simon et al. 2000), we interpret the dark oval as indicating the presence of a region which is either geometrically flatter than the outer disk or which is largely devoid of submicron grains.This study was supported by HST-GO-9136. Star Formation in Emission-Line Galaxies Between Redshifts of 0.8 and 1.6E. K. S. Hicks, M. A. Malkan (University of California, Los Angeles), H. I. Teplitz (NASA Goddard Space Flight Center), P. J. McCarthy (Observatories of the Carnegie Institution of Washington), L. Yan (SIRTF Science Center, California Institute of Technology)Optical spectra of 14 emission-line galaxies representative of the 1999 NICMOS parallel grism Ha survey of McCarthy et al. are presented. Of the 14, 9 have emission lines confirming the redshifts found in the grism survey. The higher resolution of our optical spectra improves the redshift accuracy by a factor of 5. The [O II]/Ha values of our sample are found to be more than two times lower than expected from Jansen et al. This [O II]/Ha ratio discrepancy is most likely explained by additional reddening in our Ha-selected sample [on average, as much as an extra E(B-V) = 0.6], as well as to a possible stronger dependence of the [O II]/Ha ratio on galaxy luminosity than is found in local galaxies. The result is that star formation rates (SFRs) calculated from [O II]3727 emission, uncorrected for extinction, are found to be on average 4 +/- 2 times lower than the SFRs calculated from Ha emission. Classification of emission-line galaxies as starburst or Seyfert galaxies based on comparison of the ratios [O II]/Hb and [Ne III]3869/Hb will be discussed. New Seyfert 1 diagnostics using the Ha line luminosity, H-band absolute magnitude, and Ha equivalent widths will also be presented. One galaxy is classified as a Seyfert 1 based on its broad emission lines, implying a comoving number density for Seyfert 1s of 2.5{+5.9, -2.1} x 10-5 Mpc-3. This comoving number density is a factor of 2.4{+5.5,-2.0} times higher than estimated by other surveys.Observations of Novalike Cataclysmic Variables with the Far Ultraviolet Spectroscopic ExplorerD. W. Hoard (SSC/Caltech), Paula Szkody, Albert Linnell (U Washington), K. Long (STScI), E. M. Sion (Villanova), I. Hubeny (NASA/GSFC), C. Knigge (U Southampton)Observations at short wavelengths probe the innermost region of cataclysmic variables (CVs), at the zone of interaction between the accretion flow or disk and the boundary layer and/or white dwarf. We present new spectra of three CVs (DW UMa, LS Peg, MV Lyr) obtained with the Far Ultraviolet Spectroscopic Explorer satellite. These three systems are members of the novalike class of CV, which is characterized by high accretion rates and prominent disks. The mean far-UV spectra of these three novalike CVs are remarkably different. In addition, our time-resolved FUSE spectra of DW UMa may support the recent suggestion that a weak white dwarf magnetic field is present in some or all novalikes (e.g., the SW Sextantis stars). (Our FUSE observations of another CV, the magnetic system YY Dra, will be presented at the AAS meeting by A. Linnell, et al.)A Multi-wavelength Study of Star Formation Around HII RegionsJ.L. Karr (SIRTF Science Center)I will discuss a multi-wavelength study of star formation around HII regions in the Canadian Galactic Plane Survey (CGPS). Data from the CGPS and other surveys have been used to investigate the environment of young, massive stars, their surrounding HII regions, the interaction with the surrounding cold ISM, and the nearby YSO population. The use of multi-wavelength data probes multiple components of the interstellar medium, while the survey nature of the data allows the study of a disparate range of HII regions and comparison with star formation and ISM properties in more quiescent areas. This talk will concentrate on properties of YSOs and molecular material in different regions of the survey, including molecular clump properties and the size-linewidth relation.
A Narrow-band Survey of the Environments of Galactic B[e] StarsA. P. Marston, B. McCollum (SIRTF Science Center, Caltech)We present initial results of our wide-field narrow-band H\alpha survey of the environments of galactic B[e] stars in the northern hemisphere. A total of nearly 100 stellar environments have been imaged using the Palomar 60" telescope. The B[e] stars included in our survey so far include those classified as supergiant B[e], Herbig AeBe and unclassified B[e] stars. The intent of the survey is to attempt to determine the likely evolutionary status of individual B[e] stars through analysis of their circumstellar environments. Analysis of the circumstellar environments of other massive stars (e.g., Wolf-Rayet stars) have provided valuable clues as to their likely evolutionary path through abundance analyses of ejecta materials and assessment of timescales for formation of circumstellar structures. We are particularly interested in the evolutionary status of supergiant B[e] stars and their relation to other massive, evolved stars such as Wolf-Rayets and Luminous Blue Variables. To date, approximately 25% of observed B[e] stars show circumstellar structures that are likely associated with their evolutionary past. Notably, a number of B[e] stars have associated bipolar or monopolar optical structures. Individual objects and their possible past evolution are discussed in this presentation. However, follow-up spectroscopy is required to determine whether observed features are most likely to be associated with pre-main sequence or post-main sequence phases.A New Age Measurement for Palomar 5S. L. Martell, G. H. Smith (UCO/Lick Observatory, UC Santa Cruz), C. J. Grillmair (SIRTF Science Center, California Institute of Technology)We present a new age measurement for the outer halo globular cluster Palomar 5, derived from HST V and I photometry (Grillmair & Smith 2001, AJ 122:3231). Using \alpha-dependent theoretical isochrones (Bergbusch & VandenBerg 2001, AJ 556:322) and a \chi2 minimization process allowing for variations in V-I and age, we explore the possible combinations of cluster age, metallicity, and \alpha-enhancement. We find that, assuming the parameters given in Vandenberg (2000, ApJS 129:315) ((m-M)V=16.85, E(V-I)=0.07, [Fe/H]=-1.41, [\alpha/Fe]=+0.3), the most likely age is 11.5±1 Gyr, in agreement with the age derived from ground-based B-V data (VandenBerg 2000). With the same distance modulus and reddening, but substituting the metallicity and \alpha-enhancement measured by high-dispersion Keck spectroscopy ([Fe/H]=-1.3, [\alpha/Fe]=0.2) (Smith et al 2001, AJ 123:1502), we find that the most likely age is still 11.5±1 Gyr. This work was supported by NASA through grant GO-06788.01-95A from the Space Telescope Science Institute.The Enigmatic Young Object: Walker 90/V590 MonM.R. Perez (Los Alamos National Laboratory), M.E. van den Ancker (European Southern Observatory), M.D. Joner (Brigham Young University), B. McCollum (SIRTF Science Center)Just about 20 arcminutes north-west of the Cone Nebula near the center of the open cluster NGC 2264, resides one of the most intriguing objects in this region: Walker 90 (V590 Mon, LkH\alpha 25, NGC 2264-Vas62, IRAS 06379+0950). This object, according to its spectral type (B8pe) is at least 3 magnitudes too faint in V (~ 12.7) for the cluster distance, but it shows the classical signs of a young pre-main sequence object such as highly variable H\alpha emission, Mg II emission, IR excess, and some optical variability.According to star formation processes, this object is expected to clear its primordial surroundings by becoming optically brighter, by weakening its IR excess colors and by decreasing some line emissions. This process was thought to have occurred when Bhatt & Sagar (1992, A&AS, 92, 473), from observations taken in 1989, announced that this object was 3 magnitudes brighter at V=9.7. Unfortunately, this was demonstrated to be a false alarm. Our observations for the last decade show small variabilities (around V ~ 12.7) with some brightening trends. We present a collection of archival and original data on Walker 90, ranging from optical photometry, to ultraviolet spectroscopic data. This object, unlike many other more evolved pre-main sequence objects, is either in the late stages of clearing its embryonic material or is directly behind a dark molecular cloud and is being affected by dense selective extinction. In either case, several other observational properties make this object very unique and enigmatic.
High-Resolution Mid-Infrared Observations of Very Young Stellar Objects in NGC 1333L. M. Rebull (SSC/Caltech), D. M. Cole, K. R. Stapelfeldt, M. W. Werner (JPL)We observed 22 young stellar objects in the region of NGC 1333 using the mid-infrared camera MIRLIN. NGC 1333 (in the Perseus OB2 molecular cloud complex) is a relatively well-studied region, but not at high spatial resolution in the mid-infrared. MIRLIN's 0.5 arcsecond spatial resolution allows us to look for source extension and multiplicity, and to place new constraints on spectral energy distributions. We report here new detections of 8 objects at mid-IR wavelengths. We find one object, SVS 12, that may be extended, and we confirm multiplicity in SVS 16. We find at least 1 new companion to ASR 107. We are able to classify 6 objects as Class 0-II, place strong classification constraints on 2 objects, and more loosely restrict the classification of 8 more objects. These observations will aid in interpretation of planned SIRTF observations of this cluster.Rest Frame Optical Spectra of Lyman Break Galaxies: Other Lensing Arcs around MS1512-cB58H. I. Teplitz (SIRTF Science Center), M. A. Malkan, I. S. McLean (UCLA)We present near-infrared spectra of "A2", the primary counter arc to MS1512-cB58. We detect redshifted H-alpha, [NII], [OIII], and H-beta at z=2.728± 0.001. Further, A2 has the same H-alpha/[OIII] ratio as cB58, suggesting that it is indeed another image of a single background galaxy. Published lensing reconstruction reports that A2 is a mangification of the entire source while cB58 is an image of only a part. A2 shows much weaker continuum emission than cB58 (by a factor of ~2), possibly detecting an uneven distribution of old and yound stars across the galaxy.We observe a second emission line source in the slit. This object is blueshifted from cB58 by ~150 km/sec and has a significantly lower H-alpha/[OIII] ratio, indicating that it likely an image of a different background galaxy. A Comparison of Estimates of the Black Hole Mass in the Maser Galaxy NGC 4258C. Siopis, M.C. Aller (U. Michigan), R. Bender (Universitäts-Sternwarte, Germany), G. Bower (CSC, STScI), A. Dressler (Carnegie Observatories), S.M. Faber (UCO/Lick Obs., UCSC), A.V. Filippenko (U. California, Berkeley), K. Gebhardt (U. Texas), R. Green (NOAO), C. Grillmair (SIRTF Science Center), L.C. Ho (Carnegie Observatories), J. Kormendy (U. Texas), T.R. Lauer (NOAO), J. Magorrian (Dept. of Physics, U. Durham, UK), J. Pinkney (Ohio Northern Univ.), D. Richstone (U. Michigan), S. Tremaine (Princeton Univ. Obs.)The mass of the central supermassive black hole of the SAB(s)bc galaxy NGC 4258 is determined from stellar dynamical models which use superpositions of orbits to fit photometric and kinematic data. The data include ground-based and HST/NICMOS K-band photometry as well as ground-based long-slit and HST/STIS calcium triplet spectroscopy. The data are fit to three-integral axisymmetric models using a number of plausible inclination angles, axis ratios, mass to light ratios and central point (``black hole'') masses. The combination of these parameters that best fits the data, in a \chi2 sense, then yields the ``most probable'' central black hole mass.The findings are in agreement with the M\bullet - \sigma relation, and also with the black hole mass determination of this galaxy by Miyoshi et al. (1995) using maser observations of rotating gas at 0.15 pc from the galactic center. This is the first galaxy for which the central black hole mass has been estimated independently from maser obsevations and from stellar dynamics. Support for this work was provided by NASA through grants from STScI which is operated by AURA, under NASA contract NAS 5-26555. The Search for the IR counterpart of the Soft Gamma-Ray Repeater SGR 1627-41S. Wachter (SIRTF Science Center/Caltech), S. Eikenberry (Cornell University), C. Kouveliotou, S. K. Patel, P. M. Woods (NSSTC/NASA-MSFC)Soft gamma-ray repeaters (SGRs) are a small class of high-energy transients characterized by the emission of repetitive, brief bursts of hard X-rays and soft gamma-rays. The SGR sky distribution (four are located very close to the Galactic plane, one is in the Large Magellanic Cloud) and the discovery of X-ray pulsations indicates that they are young neutron stars, an inference currently supported by the potential association of two SGRs with massive star clusters. The currently favored model attributes the various SGR properties to neutron stars with superstrong (>10^14-15 G) magnetic fields, so-called magnetars. Recently, however, a number of models involving accretion from a circumstellar disk were also proposed to explain the persistent behavior of the SGRs. Unraveling the nature of these objects has been hampered by the lack of optical/IR counterparts to SGRs which could potentially distinguish between the two models. We recently obtained Chandra observation of the field of SGR 1627-41, which provide the first precise localization of the source. We also present near-IR observations of the field acquired with the CTIO 4m telescope and will report on the search for the IR counterpart of SGR 1627-41.
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