Search Publications
CTQ 327: A New Gravitational Lens
Becker, R.; Wisotzki, L.; Gregg, M. D. +4 more
We present the second gravitationally lensed quasar discovered during the course of a Hubble Space Telescope Space Telescope Imaging Spectrograph snapshot survey for small-separation gravitational lenses. CTQ 327 is a double quasar with an image separation of 1.22" and a g-band flux ratio of roughly 5 to 1. Spectra reveal both components to be z=1…
The Star Formation Histories of Four Fields Spanning the Minor Axis of NGC 6822
Wyder, Ted K.
The star formation histories of four fields within the Local Group dwarf irregular galaxy NGC 6822 are presented. Each of the fields was imaged by the WFPC2 aboard the Hubble Space Telescope and were used to obtain VI color-magnitude diagrams for each field reaching V~=26. The magnitude of the tip of the red giant branch and the red clump were use…
An Atlas of Hubble Space Telescope Spectra and Images of Nearby Spiral Galaxies
Marconi, A.; Capetti, A.; Carollo, C. M. +17 more
We have observed 54 nearby spiral galaxies with the Space Telescope Imaging Spectrograph (STIS) on the Hubble Space Telescope to obtain optical long-slit spectra of nuclear gas disks and STIS optical (~R band) images of the central 5''×5'' of the galaxies. These spectra are being used to determine the velocity field of nuclea…
The X-Ray Properties of the Nearby Star-forming Galaxy IC 342: The XMM-Newton View
Bauer, F. E.; Brandt, W. N.; Lehmer, B.
We present results on the X-ray properties of IC 342 using a 10 ks XMM-Newton observation. Thirty-five sources are detected coincident with the disk of IC 342 (more than tripling the number known), of which ~31 are likely to be intrinsic to IC 342. This point-source population exhibits a diverse range of spectral properties and has an X-ray lumino…
Dynamical Masses of Young Stars in Multiple Systems
Nelan, E.; Schaefer, G. H.; Simon, M. +1 more
We present recent measurements of the orbital motion in the young binaries DF Tau and ZZ Tau and the hierarchical triple Elias 12 that were obtained with the Fine Guidance Sensors on the Hubble Space Telescope and at the Keck Observatory using adaptive optics. Combining these observations with previous measurements from the literature, we compute …
The Hubble Space Telescope WFPC2 B-Band Parallel Survey: A Study of Galaxy Morphology for Magnitudes 18<=B<=27
Driver, Simon P.; Windhorst, Rogier A.; Cohen, Seth H. +2 more
We present the results of the Hubble Space Telescope B-Band Parallel Survey (BBPS). It covers 0.0370 deg2 and consists of 31 shallow (four- to six-orbit), randomly selected high-latitude HST WFPC2 parallel fields with images taken in both the B (F450W) and I (F814W) filters. The goal of this survey is to morphologically classify the gal…
The Morphological Decomposition of Abell 868
Phillipps, S.; Driver, S. P.; Odewahn, S. C. +4 more
We report on the morphological luminosity functions (LFs) and radial profiles derived for the galaxy population within the rich cluster Abell 868 (z=0.153) based purely on Hubble Space Telescope imaging in F606W. We recover Schechter functions (-24.0<MF606W-5logh0.65<-16.0) within a 0.65h0.65 Mpc radius for e…
Redshifts in the Hubble Deep Field South
Sawicki, Marcin; Mallén-Ornelas, Gabriela
We present a catalog of 97 spectroscopic redshifts of z<1 galaxies in the Hubble Deep Field South (HDF-S) and its flanking fields (FFs). In the HDF-S proper we observed approximately half the galaxies brighter than I814(AB)=24 and obtained redshifts for 76% of them. Targets in our HDF-S sample were preselected to be at z<1 based o…
Imaging and Spectroscopy of Galaxies Associated with Two z~0.7 Damped Lyα Absorption Systems
White, Richard L.; Gregg, Michael D.; Lacy, Mark +3 more
We have identified galaxies near two quasars that are at the redshift of damped Lyα (DLA) systems in the UV spectra of the quasars. Both galaxies are actively forming stars. One galaxy has a luminosity close to the break in the local galaxy luminosity function, L*; the other is significantly fainter than L* and appears to be interacting with a nea…
Massive Star Clusters in Ongoing Galaxy Interactions: Clues to Cluster Formation
Keel, William C.; Borne, Kirk D.
We present HST WFPC2 observations, supplemented by ground-based Hα data, of the star-cluster populations in two pairs of interacting galaxies selected for being in very different kinds of encounters seen at different stages. Dynamical information and n-body simulations provide the details of encounter geometry, mass ratio, and timing. In NGC 5752/…