Search Publications
The Host Galaxy of GRB 031203: Implications of Its Low Metallicity, Low Redshift, and Starburst Nature
Chen, Hsiao-Wen; Graham, James R.; Dressler, Alan +6 more
We present Keck/NIRSPEC near-IR images and Magellan/IMACS optical spectroscopy of the host galaxy of GRB 031203. The host is an actively star-forming galaxy at z=0.1055+/-0.0001. This is the lowest redshift GRB to date, aside from GRB 980425. From the hydrogen Balmer lines, we infer an extinction of AV=3.62+/-0.25 or a total reddening E…
The Far-Ultraviolet Spectra of TW Hydrae. II. Models of H2 Fluorescence in a Disk
Herczeg, Gregory J.; Valenti, Jeff A.; Johns-Krull, Christopher M. +2 more
We measure the temperature of warm gas at planet-forming radii in the disk around the classical T Tauri star (CTTS) TW Hya by modeling the H2 fluorescence observed in Hubble Space Telescope Space Telescope Imaging Spectrograph and Far Ultraviolet Spectroscopic Explorer spectra. Strong Lyα emission irradiates a warm disk surface within 2…
Near-Infrared Bright Galaxies at z~=2. Entering the Spheroid Formation Epoch?
Cimatti, A.; Daddi, E.; Tozzi, P. +11 more
Spectroscopic redshifts have been measured for nine K-band luminous galaxies at 1.7<z<2.3, selected with Ks<20 in the K20 survey region of the Great Observatories Origins Deep Survey (GOODS) area. Star formation rates (SFRs) of ~100-500 Msolar yr-1 are derived when dust extinction is taken into account. Th…
An Extended Star Formation History for the Galactic Center from Hubble Space Telescope NICMOS Observations
Rich, R. Michael; Serabyn, Eugene; Figer, Donald F. +2 more
We present Hubble Space Telescope (HST) Near-Infrared Camera and Multiobject Spectrometer (NICMOS) observations as evidence that continuous star formation has created much of the central stellar cusp of the Galaxy. The data are the deepest ever obtained for a Galactic center population, being more than 50% complete for mF205W<19.3, o…
Evidence for Extended, Obscured Starbursts in Submillimeter Galaxies
Ivison, R. J.; Smail, Ian; Chapman, S. C. +2 more
We compare high-resolution optical and radio imaging of 12 luminous submillimeter galaxies at a median z=2.2+/-0.2 observed with the Hubble Space Telescope (HST) and the MERLIN and Very Large Array (VLA) radio interferometers at comparable spatial resolution, ~0.3" (~2 kpc). The radio emission is used as a tracer of the likely far-IR morphology of…
The Rest-Frame Optical Properties of SCUBA Galaxies
Ivison, R. J.; Smail, Ian; Blain, A. W. +1 more
We present optical and near-infrared photometry for a sample of 96 dusty, far-infrared-luminous galaxies. We have precise spectroscopic redshifts for all these galaxies, yielding a median redshift of =2.2. The majority, 78, are submillimeter-detected galaxies lying at z=0.2-3.6, while the remaining 18 are optically faint µJy radio galaxies a…
Colors of Active Galactic Nucleus Host Galaxies at 0.5<z<1.1 from the GEMS Survey
Wolf, C.; Barden, M.; Jahnke, K. +13 more
We present the results from a study of the host galaxies of 15 optically selected active galactic nuclei (AGNs) with 0.5<z<1.1 from the Galaxy Evolution from Morphology and SEDs project (GEMS). GEMS is a Hubble Space Telescope imaging survey of a ~28'×28' contiguous field centered on the Chandra Deep Field-South in the …
The Parsec-Scale Radio Structure of NGC 1068 and the Nature of the Nuclear Radio Source
Baum, Stefi A.; O'Dea, Christopher P.; Gallimore, Jack F.
We present sensitive, multifrequency Very Long Baseline Array (VLBA) images of the nuclear radio sources of NGC 1068. At 5 and 8.4 GHz, the radio continuum source S1, argued to mark the location of the hidden active nucleus, resolves into an elongated, ~0.8 pc source oriented nearly at right angles to the radio jet axis but more closely aligned to…
Difficulties with Recovering the Masses of Supermassive Black Holes from Stellar Kinematical Data
Emsellem, Eric; Merritt, David; Valluri, Monica
We investigate the ability of three-integral, axisymmetric, orbit-based modeling algorithms to recover the parameters defining the gravitational potential (mass-to-light ratio Υ and black hole mass M•) in spheroidal stellar systems using stellar kinematical data. We show that the potential estimation problem is generically underdetermin…
Galaxies at z~7-8: z850-Dropouts in the Hubble Ultra Deep Field
Bouwens, R. J.; Illingworth, G. D.; Thompson, R. I. +6 more
We have detected likely z~7-8 galaxies in the 144''×144'' Near-Infrared Camera and Multi-Object Spectrometer (NICMOS) observations of the Hubble Ultra Deep Field. Objects are required to be >=3 σ detections in both NICMOS bands, J110 and H160. The selection criteria for this sample are (z850