Search Publications
The Tip of the Red Giant Branch Distance to the Large Magellanic Cloud
Zaritsky, Dennis; Sakai, Shoko; Kennicutt, Robert C., Jr.
We present the I-band luminosity function of the red giant branch stars in the Large Magellanic Cloud (LMC) using the data from the Magellanic Clouds Photometric Survey (MCPS). By selecting stars in uncrowded, low-extinction regions, we observe a discontinuity in the luminosity function at I0=14.54 mag. Identifying this feature with the…
Extremely Red Objects in the Field of QSO 1213-0017: A Galaxy Concentration at Z=1.31
Dickinson, Mark E.; Steidel, Charles C.; Graham, James R. +4 more
We have discovered a concentration of extremely red objects (EROs; R-K>6) in the field of the z=2.69 quasar QSO 1213-0017 (UM 485), which is a significant overabundance compared with the field ERO surface density. The optical/near-IR colors of the EROs and numerous other red galaxies in this field are consistent with elliptical galaxies at z=1-…
Stellar Populations in the Phoenix Dwarf (DIRR/DSPH) Galaxy as Observed by Hubble Space Telescope WFPC2
Grillmair, Carl; Smith, Graeme H.; Holtzman, Jon A.
We present Hubble Space Telescope Wide Field Planetary Camera 2 photometry of the central regions of the Phoenix dwarf galaxy. Accurate photometry allows us to (1) confirm the existence of the horizontal branch previously detected by ground-based observations and use it to determine a distance to Phoenix, (2) clearly detect the existence of multip…
The Hubble Deep Field South: STIS Imaging
Ferguson, Henry C.; Baum, Stefi A.; Brown, Thomas M. +18 more
We present the imaging observations made with the Space Telescope Imaging Spectrograph (STIS) of the Hubble Deep Field South. The field was imaged in four bandpasses: a clear CCD bandpass for 156 ks, a long-pass filter for 22-25 ks pixel-1 typical exposure, a near-UV bandpass for 23 ks, and a far-UV bandpass for 52 ks. The clear, visibl…
Recent Changes in the Near-Ultraviolet and Optical Structure of η Carinae
Smith, Nathan; Humphreys, Roberta M.; Davidson, Kris +1 more
Multiepoch HST/WFPC2 images of η Carinae are used to investigate the relationship between the photometric variability of the circumstellar nebula and the variability of the central star. In the past few years, the central star has brightened considerably, and the response of the reflection nebula to this brightening has been surprisingly complex. …
Color Gradients in Early-Type Galaxies in Clusters at Redshift 0.37-0.56
Tamura, Naoyuki; Ohta, Kouji
Color gradients in elliptical galaxies in distant clusters (z=0.37-0.56) are examined by using the archival deep imaging data of the Wide Field Planetary Camera 2 on board the Hubble Space Telescope (HST). Obtained color gradients are compared with the two model gradients to examine the origin of the color gradients. In one model, a color gradient…
Hubble Space Telescope NICMOS Observations of the Host Galaxies of Powerful Radio Sources: Does Size Matter?
O'Dea, C. P.; Lehnert, M. D.; Fanti, R. +3 more
We present near-infrared J- and K-band imaging of a sample of powerful radio source host galaxies with the Hubble Space Telescope NICMOS2 camera. These sources have been selected on their double-lobed radio structure and include a wide range of projected radio source sizes. The largest projected linear sizes range from the compact gigahertz peaked…
Circumnuclear Star Formation in the Early-Type Resonance Ring Barred Spiral Galaxy NGC 1326
Buta, R.; Treuthardt, Patrick M.; Crocker, D. A. +1 more
We present multiband WFPC2 images of the nuclear ring of NGC 1326, an early-type southern barred spiral in the nearby Fornax galaxy cluster. The ring is a typical example of a 1 kpc-sized star-forming ring located in the region of the inner Lindblad resonances with the weak primary bar. The images reveal nearly 1000 point sources in and around the…
Hubble Space Telescope Photometry of the Metal-rich Globular Clusters NGC 6624 and NGC 6637
Da Costa, Gary S.; Demarque, Pierre; Christian, Carol A. +3 more
We have observed the metal-rich globular clusters NGC 6624 and NGC 6637 (M69) using the planetary camera of the WFPC2 on the Hubble Space Telescope (HST). Observations of the Ca II triplet lines in giant stars in these clusters show that NGC 6624 and NGC 6637 have metallicities on the Zinn and West scale of [Fe/H]=-0.63+/-0.09 and -0.65+/-0.09, on…
Measurements of the Diffuse Ultraviolet Background and the Terrestrial Airglow with the Space Telescope Imaging Spectrograph
Ferguson, Henry C.; Brown, Thomas M.; Gardner, Jonathan P. +3 more
Far-UV observations in and near the Hubble Deep Fields demonstrate that the Space Telescope Imaging Spectrograph (STIS) may obtain unique and precise measurements of the diffuse far-ultraviolet background. Although STIS is not the ideal instrument for such measurements, high-resolution images allow Galactic and extragalactic objects to be masked t…