Search Publications
Keck Spectroscopy of Globular Clusters in the Virgo Cluster Dwarf Elliptical Galaxy VCC 1386
Conselice, Christopher J.
We present the results of a Keck spectroscopic study of globular clusters associated with the Virgo Cluster dwarf elliptical galaxy (dE) VCC 1386. We analyze blue spectroscopic absorption lines from 3500 to 5500 Å for 13 globular cluster candidates and confirm that five are associated with VCC 1386. By comparing metal and Balmer line indices of th…
Bright X-Ray Transients in M31: 2004 July XMM-Newton Observations
Trudolyubov, Sergey; Priedhorsky, William; Cordova, France
We present the results of X-ray observations of four bright transients sources detected in the 2004 July XMM-Newton observations of the central bulge of M31. Two X-ray sources, XMMU J004315.5+412440 and XMMU J004144.7+411110, were discovered for the first time. Two other sources, CXOM31 J004309.9+412332 and CXOM31 J004241.8+411635, were previously…
Resolving the Dusty Circumstellar Structure of the Enigmatic Symbiotic Star CH Cygni with the MMT Adaptive Optics System
Bieging, John H.; Marengo, Massimo; Hoffmann, William F. +6 more
We imaged the symbiotic star CH Cyg and two PSF calibration stars using the unique 6.5 m MMT deformable secondary adaptive optics system. Our high-resolution (FWHM = 0.3"), very high Strehl (98%+/-2%), mid-infrared (9.8 and 11.7 µm) images of CH Cyg allow us to probe finer length scales than ever before for this object. CH Cyg is significant…
The First Direct Spectroscopic Detection of a White Dwarf Primary in an AM CVn System
Szkody, Paula; Howell, Steve B.; Sion, Edward M. +2 more
We report the results of a synthetic spectral analysis of HST STIS spectra of the AM CVn-type cataclysmic variable CP Eri obtained when the system was in quiescence. The FUV spectrum is best fitted by a helium-dominated, hybrid composition (DBAZ) white dwarf with Teff~17,000+/-1000 K, logg~8, He/H abundance ratio by number ~1000, metall…
Delayed Photoionization Feedback in a Super Star Cluster in SBS 0335-052E
Vanzi, Leonardo; Sauvage, Marc; Thompson, Rodger I. +2 more
SBS 0335-052 is a well-studied blue compact dwarf galaxy with one of the lowest metallicities of any known galaxy. It also contains six previously identified super star clusters. We combine archival HST NICMOS images in the Paα line and the 1.6 µm continuum of the eastern component, SBS 0335-052E, with other space- and ground-based data to p…
Color, Structure, and Star Formation History of Dwarf Galaxies over the Last ~3 Gyr with GEMS and SDSS
Bell, Eric F.; Wolf, Christian; Rix, Hans-Walter +7 more
We present a study of the colors, structural properties, and star formation histories for a sample of ~1600 dwarfs over look-back times of ~3 Gyr (z=0.002-0.25). The sample consists of 401 distant dwarfs drawn from the Galaxy Evolution from Morphologies and SEDs (GEMS) survey, which provides high-resolution Hubble Space Telescope (HST) Advanced Ca…
The Deuterium, Oxygen, and Nitrogen Abundance toward LSE 44
Sembach, K. R.; Chayer, P.; Hébrard, G. +2 more
We present measurements of the column densities of interstellar D I, O I, N I, and H2 made with the Far Ultraviolet Spectroscopic Explorer (FUSE) and of H I made with the International Ultraviolet Explorer (IUE) toward the sdO star LSE 44 [(l, b)=(313.37d, +13.49d) d=554+/-66 pc; z=+129+/-15 pc]. This target is among the seven most dist…
Morphology of Spitzer 24 µm Detected Galaxies in the UDF: The Links between Star Formation and Galaxy Morphology
Le Floc'h, E.; Papovich, C.; Rieke, G. H. +2 more
We have studied the morphologies of infrared-luminous galaxies at 0.3<=z<1.4 in the HST Ultra Deep Field (UDF) by calculating concentration and asymmetry indices and comparing the results with similar calculations for: (1) galaxies at similar redshift that are less infrared-active, and (2) local luminous infrared galaxies [LIRGs; LIR
An Infrared Imaging Study of the Bipolar Proto-Planetary Nebula IRAS 16594-4656
Volk, Kevin; Kwok, Sun; Hrivnak, Bruce J. +1 more
High-resolution mid-infrared images have been obtained in N and Q band for the proto-planetary nebula IRAS 16594-4656. A bright equatorial torus and a pair of bipolar lobes can clearly be seen in the infrared images. The torus appears thinner at the center than at the edges, suggesting that it is viewed nearly edge-on. The infrared lobes correspon…
An XMM-Newton Search for X-Ray Emission from the Microlensing Event MACHO-96-BLG-5
Kaastra, J. S.; de Plaa, J.; Elia, D. +3 more
MACHO-96-BLG-5 was a microlensing event observed toward the bulge of the Galaxy with an exceptionally long duration of ~970 days. The microlensing parallax fit parameters were used to estimate a lens mass M=6+10-3 Msolar, corresponding to a distance d in the range 0.5-2 kpc. The upper limit on the absolute brightne…