Search Publications
The X-Ray Properties of the Most Luminous Quasars from the Sloan Digital Sky Survey
Brandt, W. N.; Garmire, G. P.; Chartas, G. +4 more
Utilizing 21 new Chandra observations as well as archival Chandra, ROSAT, and XMM-Newton data, we study the X-ray properties of a representative sample of 59 of the most optically luminous quasars in the universe (Mi~-29.3 to -30.2) spanning a redshift range of z~1.5-4.5. Our full sample consists of 32 quasars from the Sloan Digital Sky…
The Compact, Conical, Accretion-Disk Warm Absorber of the Seyfert 1 Galaxy NGC 4051 and Its Implications for IGM-Galaxy Feedback Processes
Elvis, Martin; Nicastro, Fabrizio; Mathur, Smita +4 more
Using a 100 ks XMM-Newton exposure of NGC 4051, we show that the time evolution of the ionization state of the X-ray absorbers in response to the rapid and highly variable X-ray continuum constrains all the main physical and geometrical properties of an AGN ``warm absorber'' wind. The absorber consists of two different ionization components, with …
Hα Tail, Intracluster H II Regions, and Star Formation: ESO 137-001 in Abell 3627
Sun, M.; Donahue, M.; Voit, G. M.
We present the discovery of a 40 kpc Hα tail and at least 29 emission-line objects downstream of a star-forming galaxy, ESO 137-001, in the rich, nearby cluster A3627. The galaxy is known to possess a dramatic 70 kpc X-ray tail. The detected Hα tail coincides positionally with the X-ray tail. The Hα emission in the galaxy is sharply truncated on t…
Probing the Dark Matter and Gas Fraction in Relaxed Galaxy Groups with X-Ray Observations from Chandra and XMM-Newton
Humphrey, Philip J.; Buote, David A.; Brighenti, Fabrizio +4 more
We present radial mass profiles within ~0.3rvir for 16 relaxed galaxy groups-poor clusters (kT range 1-3 keV) selected for optimal mass constraints from the Chandra and XMM-Newton data archives. After accounting for the mass of hot gas, the resulting mass profiles are described well by a two-component model consisting of dark matter, re…
Iron Line and Diffuse Hard X-Ray Emission from the Starburst Galaxy M82
Heckman, Timothy M.; Strickland, David K.
We examine the properties of the diffuse hard X-ray emission in the classic starburst galaxy M82. We use new Chandra ACIS-S observations in combination with reprocessed archival Chandra ACIS-I and XMM-Newton observations. We find that E~6.7 keV Fe Heα emission is present in the central |r|<200 pc, |z|<100 pc of M82 in all data sets, in addit…
X-Ray Thermal Coronae of Galaxies in Hot Clusters: Ubiquity of Embedded Mini-Cooling Cores
Vikhlinin, A.; Forman, W.; Sun, M. +3 more
We present a systematic investigation of X-ray thermal coronae in 157 early-type and 22 late-type galaxies from a survey of 25 hot (kT>3 keV), nearby (z<0.05) clusters, based on Chandra archival data. Cool galactic coronae (kT=0.5-1.1 keV generally) have been found to be common, >60% in LKs>2L* galaxies…
Molecular Hydrogen Emission from Protoplanetary Disks. II. Effects of X-Ray Irradiation and Dust Evolution
Tsujimoto, M.; Nomura, H.; Aikawa, Y. +2 more
Detailed models for the density and temperature profiles of gas and dust in protoplanetary disks are constructed by taking into account X-ray and UV irradiation from a central T Tauri star, as well as dust size growth and settling toward the disk midplane. The spatial and size distributions of dust grains are numerically computed by solving the co…
The X-Ray Concentration-Virial Mass Relation
Humphrey, Philip J.; Buote, David A.; Brighenti, Fabrizio +4 more
We present the concentration (c)-virial mass (M) relation of 39 galaxy systems ranging in mass from individual early-type galaxies up to the most massive galaxy clusters, (0.06-20)×1014 Msolar. We selected for analysis the most relaxed systems possessing the highest quality data currently available in the Chandra and XMM-Newt…
X-Ray Absorption from the Milky Way Halo and the Local Group
Bregman, Joel N.; Lloyd-Davies, Edward J.
Million degree gas is present at near-zero redshift and is due to either a gaseous Galactic halo or a more diffuse but very massive Local Group medium. We can discriminate between these models because the column densities should depend on location in the sky, either relative to the Galaxy bulge or to the M31-Milky Way axis. To search for these sig…
Quasi-periodic Variability in NGC 5408 X-1
Cropper, Mark; Soria, Roberto; Mushotzky, Richard F. +3 more
We report the discovery with XMM-Newton of quasi-periodic variability in the 0.2-10 keV X-ray flux from the ULX NGC 5408 X-1. The average power spectrum of all EPIC-pn data reveals a strong 20 mHz QPO with an average amplitude (rms) of 9% and a coherence Q≡ν0/σ~6. In a 33 ks time interval when the 20 mHz QPO is strongest we also find ev…