Search Publications
Chandra Observations of the Cloverleaf Quasar H1413+117: A Unique Laboratory for Microlensing Studies of a LoBAL Quasar
Agol, E.; Chartas, G.; Gallagher, S. C. +1 more
We present new results uncovered by a reanalysis of a Chandra observation of the gravitationally lensed, low-ionization broad absorption line (LoBAL) quasar H1413+117. Previous analyses of the same Chandra observation led to the detection of a strong, redshifted Fe Kα line from the combined spectrum of all images. We show that the redshifted Fe Kα…
The XMM-LSS survey. First high redshift galaxy clusters: Relaxed and collapsing systems
Altieri, B.; Valtchanov, I.; Pierre, M. +11 more
We present five newly found galaxy clusters at z>0.6 from the XMM Large-Scale Structure Survey (XMM-LSS). All five objects are extended X-ray sources in the XMM images. For three of them we have sufficient spectroscopically confirmed member galaxies that an estimate of the velocity dispersion is possible: XLSSC 001 at z=0.613 and &sigma
XMM-Newton observations of the binary cluster system Abell 399/401
Sakelliou, Irini; Ponman, Trevor J.
Both Abell 399 and Abell 401 are rich clusters of galaxies, with global temperatures of 7.2 (Abell 399) and 8.5 keV (Abell 401), respectively. They lie at a projected separation of ~3 Mpc, forming a close pair. We have observed the system with the XMM-Newton satellite. The data of each cluster show significant departures from our idealized picture…
Image simulation with shapelets
Refregier, Alexandre; Conselice, Christopher J.; Massey, Richard +2 more
We present a method to simulate deep sky images, including realistic galaxy morphologies and telescope characteristics. To achieve a wide diversity of simulated galaxy morphologies, we first use the shapelets formalism to parametrize the shapes of all objects in the Hubble Deep Fields. We measure this distribution of real galaxy morphologies in sh…
Evidence of an Intermediate-Mass Black Hole: Chandra and XMM-Newton Observations of the Ultraluminous Supersoft X-Ray Source in M101 during Its 2004 Outburst
Kong, A. K. H.; Yuan, F.; Di Stefano, R.
We report the results of Chandra and XMM-Newton observations of a new outburst of an ultraluminous supersoft X-ray source in M101. CXOU J140332.3+542103 was observed in a low-luminosity state (LX~1037 ergs s-1) between 2004 January and May. The low-state X-ray spectra were relatively hard; the combined low-state sp…
NGC 3125-1: The Most Extreme Wolf-Rayet Star Cluster Known in the Local Universe
Leitherer, Claus; Chandar, Rupali; Tremonti, Christy A.
We use Space Telescope Imaging Spectrograph long-slit ultraviolet spectroscopy of local starburst galaxies to study the massive star content of a representative sample of super-star clusters, with a primary focus on their Wolf-Rayet (W-R) content as measured from the He II λ1640 emission feature. The goals of this work are threefold. First, we qua…
Properties of RR Lyrae stars in the inner regions of the Large Magellanic Cloud
Cook, K. H.; Freeman, K. C.; Minniti, D. +3 more
We present the radial velocities, metallicities and the K-band magnitudes of 74 RR Lyrae stars in the inner regions of the LMC. The intermediate resolution spectra and infrared images were obtained with FORS1 at the ESO VLT and with the SOFI infrared imager at the ESO NTT. The best 43 RR Lyrae with measured velocities yield an observed velocity di…
An X-Ray Jet from a White Dwarf: Detection of the Collimated Outflow from CH Cygni with Chandra
Sokoloski, J. L.; Galloway, Duncan K.
Most symbiotic stars consist of a white dwarf accreting material from the wind of a red giant. An increasing number of these objects have been found to produce jets. Analysis of archival Chandra data of the symbiotic system CH Cygni reveals faint extended emission to the south, aligned with the optical and radio jets seen in earlier Hubble Space T…
Ultra-Compact Dwarf Galaxies in Galaxy Clusters
Ferguson, Henry C.; Drinkwater, Michael J.; Gregg, Michael D. +5 more
We review the evidence that the ultra-compact dwarf (UCD) galaxies we recently discovered in the Fornax Cluster form a new, previously unknown class of galaxies and we discuss possible scenarios for their formation. We then present recent results that UCDs are also present in the Virgo Cluster, and that there is a much larger than expected populat…
Density structures inside the plasmasphere: Cluster observations
André, M.; Santolik, O.; de Keyser, J. +11 more
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