Search Publications
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…
The Cassini Ion and Neutral Mass Spectrometer (INMS) Investigation
Luhmann, J. G.; Ip, W. -H.; McNutt, R. L. +13 more
The Cassini Ion and Neutral Mass Spectrometer (INMS) investigation will determine the mass composition and number densities of neutral species and low-energy ions in key regions of the Saturn system. The primary focus of the INMS investigation is on the composition and structure of Titan’s upper atmosphere and its interaction with Saturn’s magneto…
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…
Spatially resolved X-ray spectroscopy of cooling clusters of galaxies
Böhringer, H.; Kaastra, J. S.; Branduardi-Raymont, G. +7 more
We present spatially resolved X-ray spectra taken with the EPIC cameras of XMM-Newton of a sample of 17 cooling clusters and three non-cooling clusters for comparison. The deprojected spectra are analyzed with a multi-temperature model, independent of any a priori assumptions about the physics behind the cooling and heating mechanisms. All cooling…
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 …
Detection of a Red Supergiant Progenitor Star of a Type II-Plateau Supernova
Smartt, Stephen J.; Mattila, Seppo; Gilmore, Gerard F. +4 more
We present the discovery of a red supergiant star that exploded as supernova 2003gd in the nearby spiral galaxy M74. The Hubble Space Telescope (HST) and the Gemini Telescope imaged this galaxy 6 to 9 months before the supernova explosion, and subsequent HST images confirm the positional coincidence of the supernova with a single resolved star tha…
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…
Structure of the Magnetic Reconnection Diffusion Region from Four-Spacecraft Observations
André, M.; Khotyaintsev, Y.; Vaivads, A. +6 more
Magnetic reconnection leads to energy conversion in large volumes in space but is initiated in small diffusion regions. Because of the small sizes of the diffusion regions, their crossings by spacecraft are rare. We report four-spacecraft observations of a diffusion region encounter at the Earth's magnetopause that allow us to reliably distinguish…
A Large Sample of Spectroscopic Redshifts in the ACS-GOODS Region of the Hubble Deep Field North
Capak, P.; Barger, A. J.; Cowie, L. L. +2 more
We report the results of an extensive spectroscopic survey of galaxies in the roughly 160 arcmin2 ACS-GOODS region surrounding the Hubble Deep Field North (HDF-N). We have identified 892 galaxies or stars with z'<24, R<24.5, or B<25 in the region. The spectra were obtained with either the DEIMOS or LRIS spectrographs…