Search Publications
Chandra and XMM-Newton Observations of the Nucleus of Centaurus A
Hardcastle, M. J.; Worrall, D. M.; Forman, W. R. +4 more
We present X-ray spectra of the nucleus of the nearby radio galaxy Centaurus A from observations with the XMM-Newton EPIC CCD cameras (two exposures separated by 12 months) and the Chandra HETGS. For the first time in an FR I type galaxy, we resolve fluorescent Kα emission from cold, neutral, or near-neutral iron at 6.4 keV, with an rms line width…
The Fundamental Plane of Field Early-Type Galaxies at z = 1
Rix, H. -W.; van der Wel, A.; Franx, M. +1 more
We present deep VLT spectra of early-type galaxies at z~1 in the Chandra Deep Field-South, from which we derive velocity dispersions. Together with structural parameters from Hubble Space Telescope imaging, we can study the fundamental plane for field early-type galaxies at that epoch. We determine accurate mass-to-light ratios (M/L) and colors fo…
The Far-Infrared Spectrum of the Sagittarius B2 Region: Extended Molecular Absorption, Photodissociation, and Photoionization
Cernicharo, José; Goicoechea, Javier R.; Rodríguez-Fernández, Nemesio J.
We present large-scale 9'×27' (~25pc×70pc) far-IR observations around Sgr B2 using the Long-Wavelength Spectrometer (LWS) on board the Infrared Space Observatory (ISO). The spectra are dominated by the strong continuum emission of dust, the widespread molecular absorption of light hydrides (OH, CH, and H2O), and th…
The Stellar Populations of Low-Luminosity Active Galactic Nuclei. I. Ground-based Observations
Heckman, Timothy; Schaerer, Daniel; Leitherer, Claus +6 more
We present a spectroscopic study of the stellar populations of low-luminosity active galactic nuclei (LLAGNs). Our main goal is to determine whether the stars that live in the innermost (100 pc scale) regions of these galaxies are in some way related to the emission-line properties, which would imply a link between the stellar population and the i…
A Slow Merger History of Field Galaxies since z ~ 1
Conselice, Christopher J.; Ellis, Richard S.; Kodama, Tadayuki +2 more
Using deep infrared observations conducted with the CISCO imager on the Subaru Telescope, we investigate the field-corrected pair fraction and the implied merger rate of galaxies in redshift survey fields with Hubble Space Telescope (HST) imaging. In the redshift interval, 0.5<z<1.5, the fraction of infrared-selected pairs increases only mod…
The Optical Counterpart of an Ultraluminous X-Ray Source in NGC 5204
Bregman, Joel N.; Seitzer, Patrick; Liu, Ji-Feng
Ultraluminous X-ray (ULX) sources are extranuclear point sources in external galaxies with LX=1039-1041 ergs s-1 and are among the most poorly understood X-ray sources. To help understand their nature, we are trying to identify their optical counterparts by combining images from the Hubble Space Telescop…
Flare Ribbon Expansion and Energy Release Rate
Shibata, Kazunari; Masuda, Satoshi; Shimojo, Masumi +3 more
We have examined the relation between the evolution of the Hα flare ribbons and the released magnetic energy in a solar flare that occurred on 2001 April 10. Based on the magnetic reconnection model, the released energy was quantitatively calculated by using the photospheric magnetic field strengths and separation speeds of the fronts of the Hα fl…
On a Surge: Properties of an Emerging Flux Region
Liu, Yu; Kurokawa, Hiroki
A surge event with multi-instrument and multiwavelength observations is presented. The event occurred in a surge-productive region on 2001 August 30. TRACE white-light images, Huairou vector magnetograms, and Hβ filtergrams show that this surge was closely associated with new bipoles that emerged in 1 hr. Evidence of enhanced magnetic cancellation…
The Deep Lens Survey Transient Search. I. Short Timescale and Astrometric Variability
Becker, A. C.; Frail, D. A.; Halpern, J. +8 more
We report on the methodology and first results from the Deep Lens Survey (DLS) transient search. We utilize image subtraction on survey data to yield all sources of optical variability down to 24th magnitude. Images are analyzed immediately after acquisition, at the telescope, and in near-real time, to allow for follow-up in the case of time-criti…
Morphologies and Spectral Energy Distributions of Extremely Red Galaxies in the GOODS-South Field
Papovich, Casey; Ferguson, Henry C.; Giavalisco, Mauro +12 more
Using U'- through Ks-band imaging data in the Great Observatories Origins Deep Survey-South (GOODS-South) field, we construct a large, complete sample of 275 extremely red objects (EROs; Ks<22.0, R-Ks>3.35 AB), all with deep Hubble Space Telescope Advanced Camera for Surveys imaging in B435