Search Publications
The 2-10 keV luminosity as a Star Formation Rate indicator
Ranalli, P.; Comastri, A.; Setti, G.
Radio and far infrared luminosities of star-forming galaxies follow a tight linear relation. Making use of ASCA and BeppoSAX observations of a well-defined sample of nearby star-forming galaxies, we argue that tight linear relations hold between the X-ray, radio and far infrared luminosities. The effect of intrinsic absorption is investigated taki…
Discovery of a Binary Active Galactic Nucleus in the Ultraluminous Infrared Galaxy NGC 6240 Using Chandra
Kaastra, J. S.; Burwitz, V.; Hasinger, G. +3 more
Ultraluminous infrared galaxies (ULIRGs) are outstanding due to their huge luminosity output in the infrared, which is predominantly powered by superstarbursts and/or hidden active galactic nuclei (AGNs). NGC 6240 is one of the nearest ULIRGs and is considered a key representative of its class. Here we report the first high-resolution imaging spec…
A Census of the Young Cluster IC 348
Luhman, K. L.; Bouvier, J.; Stauffer, John R. +4 more
We present a new census of the stellar and substellar members of the young cluster IC 348. We have obtained images at I and Z for a 42'×28' field encompassing the cluster and have combined these measurements with previous optical and near-infrared photometry. From spectroscopy of candidate cluster members appearing in these d…
Interplanetary coronal mass ejections in the near-Earth solar wind during 1996-2002
Cane, H. V.; Richardson, I. G.
We summarize the occurrence of interplanetary coronal mass ejections (ICMEs) in the near-Earth solar wind during 1996-2002, corresponding to the increasing and maximum phases of solar cycle 23. In particular, we give a detailed list of such events. This list, based on in situ observations, is not confined to subsets of ICMEs, such as "magnetic clo…
High-Resolution X-Ray Spectroscopic Constraints on Cooling-Flow Models for Clusters of Galaxies
Kaastra, J. S.; Ferrigno, C.; Kahn, S. M. +5 more
We present high-resolution X-ray spectra of 14 putative cooling-flow clusters of galaxies obtained with the Reflection Grating Spectrometer on XMM-Newton. The clusters in the sample span a large range of temperatures and mass deposition rates. Various of these spectra exhibit line emission from O VIII, Ne X, Mg XII and XI, Al XIII and XII, Si XIV …
Quasars, their host galaxies and their central black holes
McLure, R. J.; Dunlop, J. S.; Hughes, D. H. +3 more
We present the final results from our deep Hubble Space Telescope (HST) imaging study of the host galaxies of radio-quiet quasars (RQQs), radio-loud quasars (RLQs) and radio galaxies (RGs). We describe and analyse new Wide Field & Planetary Camera 2 (WFPC2) R-band observations for 14 objects, which when combined with the first tranche of HST i…
SPI: The spectrometer aboard INTEGRAL
Boggs, S.; Knödlseder, J.; von Kienlin, A. +25 more
SPI is a high spectral resolution gamma-ray telescope on board the ESA mission INTEGRAL (International Gamma Ray Astrophysics Laboratory). It consists of an array of 19 closely packed germanium detectors surrounded by an active anticoincidence shield of BGO. The imaging capabilities of the instrument are obtained with a tungsten coded aperture mas…
A Direct Measurement of Major Galaxy Mergers at z<~3
Papovich, Casey; Dickinson, Mark; Conselice, Christopher J. +1 more
This paper presents direct evidence for hierarchical galaxy assembly out to redshifts z~3. We identify major mergers using the model-independent CAS (concentration, asymmetry, clumpiness) physical morphological system on galaxies detected, and photometrically selected, in the WFPC2 and NICMOS Hubble Deep Field North. We specifically use the asymme…
The Extremely Metal-poor, Neutron Capture-rich Star CS 22892-052: A Comprehensive Abundance Analysis
Beers, Timothy C.; Truran, James W.; Hill, Vanessa +9 more
High-resolution spectra obtained with three ground-based facilities and the Hubble Space Telescope (HST) have been combined to produce a new abundance analysis of CS 22892-052, an extremely metal-poor giant with large relative enhancements of neutron capture elements. A revised model stellar atmosphere has been derived with the aid of a large numb…
HST Photometry of Dwarf Elliptical Galaxies in Coma, and an Explanation for the Alleged Structural Dichotomy between Dwarf and Bright Elliptical Galaxies
Graham, Alister W.; Guzmán, Rafael
As part of a research program exploring how and why dwarf elliptical (dE) galaxies depart from the fundamental plane defined by luminous elliptical (E) galaxies, we have analyzed archival Hubble Space Telescope F606W images of a sample of 18 dE galaxy candidates in the Coma Cluster. We model the full radial extent of their light profiles by simult…