Search Publications
Very Large Array Plus Pie Town Astrometry of 46 Radio Stars
Zacharias, N.; Claussen, M. J.; Johnston, K. J. +4 more
We have used the Very Large Array, linked with the Pie Town Very Long Baseline Array antenna, to determine astrometric positions of 46 radio stars in the International Celestial Reference Frame (ICRF). Positions were obtained in the ICRF directly through phase referencing of the stars to nearby ICRF quasars whose positions are accurate at the 0.25…
Emission-Line Spectroscopy of a Damped Lyα-absorbing Galaxy at z = 0.437
Kulkarni, Varsha P.; Chun, Mark R.; Gharanfoli, Soheila +1 more
We present Keck LRIS spectra of a candidate damped Lyα (DLA) galaxy toward the QSO 3C 196 (zem=0.871). The DLA absorption system has a redshift of zDLA=0.437, and a galaxy at 1.5" from the QSO has been identified in high-resolution imaging with WFPC2 on board the Hubble Space Telescope. We have detected emission lines of [O I…
The Toomre Sequence Revisited with HST NICMOS: Nuclear Brightness Profiles and Colors of Interacting and Merging Galaxies
Böker, Torsten; van der Marel, Roeland P.; Zabludoff, Ann I. +4 more
We discuss the near-infrared (NIR) properties of the nuclei in the 11 merging galaxies of the Toomre sequence, based on high spatial resolution J, H, and K imaging data using NICMOS on board the Hubble Space Telescope (HST). The observations are less affected by dust extinction than our previous HST WFPC2 observations and offer higher spatial reso…
The Opacity of Spiral Galaxy Disks. VIII. Structure of the Cold ISM
Calzetti, D.; Gordon, K. D.; Allen, Ronald J. +6 more
The quantity of dust in a spiral disk can be estimated using the dust's typical emission or the extinction of a known source. In this paper we compare two techniques, one based on emission and one on absorption, applied to sections of 14 disk galaxies. The two measurements reflect, respectively, the average and apparent optical depth of a disk sec…
The Young Stellar Population of NGC 4214 as Observed with the Hubble Space Telescope. I. Data and Methods
Úbeda, Leonardo; MacKenty, John W.; Maíz-Apellániz, Jesús
We present the data and methods that we have used to perform a detailed UV-optical study of the nearby dwarf starburst galaxy NGC 4214 using multifilter Hubble Space Telescope WFPC2 and STIS photometry. We explain the process followed to obtain high-quality photometry and astrometry of the stellar and cluster populations of this galaxy. We describ…
First Constraints on Rings in the Pluto System
Stern, S. A.; Steffl, A. J.
Simple theoretical calculations have suggested that small-body impacts onto Pluto's newly discovered small satellites, Nix and Hydra, are capable of generating time-variable rings or dust sheets in the Pluto system. Using Hubble Space Telescope ACS data obtained on 2006 February 15 and 2006 March 2, we find no observational evidence for such a rin…
XMM-Newton Observations of the Cataclysmic Variable GW Librae
Hellier, Coel; Szkody, Paula; Mukai, Koji +4 more
XMM-Newton observations of the accreting, pulsating white dwarf in the quiescent dwarf nova GW Librae were conducted to determine whether the nonradial pulsations present in previous UV and optical data affect the X-ray emission. The nonradial pulsations are evident in the simultaneous Optical Monitor data but are not detected in the X-ray with an…
Infrared Study of J-Type Carbon Stars Based on Infrared Astronomical Satellite, Two Micron All Sky Survey, and Infrared Space Observatory Data
Chen, Pei-Sheng; Yang, Xiao-Hong; Zhang, Pin
We collected 113 J-type carbon stars from the published literature. Observations from 2MASS, IRAS, and ISO show that, except for silicate carbon stars in the J-type carbon star domain, the infrared properties of the other J-type carbon stars are quite similar to those of ordinary carbon stars. The above results imply that the chemical peculiarity …
Gaps in the Cloud Cover? Comparing Extinction Measures in Spiral Disks
Smith, J. D.; Calzetti, D.; Kennicutt, R. C. +11 more
Dust in galaxies can be mapped either by the FIR/submillimeter emission, the optical or infrared reddening of starlight, or the extinction of a known background source. We compare two dust extinction measurements for a set of 15 sections in 13 nearby galaxies to determine the scale of the dusty interstellar medium (ISM) responsible for disk opacit…
Identification of Variable Stars in COROT's First Main Observing Field (LRc1)
Deeg, H.; Deleuil, M.; Erikson, A. +7 more
The COROT space mission will monitor several target fields for up to 150 days to perform asteroseismology and to search for extrasolar planets by photometric transits. Variable stars in the target fields are important objects for additional scientific studies but can also disturb the search for planetary transits. A variability characterization of…