Search Publications
Observational Evidence for High Neutronization in Supernova Remnants: Implications for Type Ia Supernova Progenitors
Mori, Hideyuki; Yamaguchi, Hiroya; Badenes, Carles +8 more
The physical process whereby a carbon-oxygen white dwarf explodes as a Type Ia supernova (SN Ia) remains highly uncertain. The degree of neutronization in SN Ia ejecta holds clues to this process because it depends on the mass and the metallicity of the stellar progenitor, and on the thermodynamic history prior to the explosion. We report on a new…
Shedding Light on the Compton-thick Active Galactic Nucleus in the Ultraluminous Infrared Galaxy UGC 5101 with Broadband X-Ray Spectroscopy
Imanishi, Masatoshi; Tanimoto, Atsushi; Ueda, Yoshihiro +3 more
We report the broadband X-ray spectra of the ultraluminous infrared galaxy (ULIRG) UGC 5101 in the 0.25-100 keV band observed with the Swift/Burst Alert Telescope (BAT), Nuclear Spectroscopic Telescope Array (NuSTAR), Suzaku, XMM-Newton, and Chandra. A Compton-thick active galactic nucleus (AGN) obscured with a hydrogen column density of ≈ 1.3× {1…
The Origin of the Iron-rich Knot in Tycho’s Supernova Remnant
Petre, Robert; Yamaguchi, Hiroya; Hughes, John P. +5 more
X-ray observations of supernova remnants (SNRs) allow us to investigate the chemical inhomogeneity of ejecta, offering unique insight into the nucleosynthesis in supernova explosions. Here we present detailed imaging and spectroscopic studies of the “Fe knot” located along the eastern rim of the Type Ia SNR Tycho (SN 1572) using Suzaku and Chandra…
Probing the Anisotropy of the Milky Way Gaseous Halo-II: Sightline toward Mrk 509
Krongold, Y.; Mathur, S.; Gupta, A.
Hot, million degree gas appears to pervade the Milky Way halo, containing a large fraction of the Galactic missing baryons. This circumgalactic medium (CGM) is probed effectively in X-rays, both in absorption and in emission. The CGM also appears to be anisotropic, so we have started a program to determine CGM properties along several sightlines b…
The Broadband Spectral Variability of Holmberg IX X-1
Harrison, F. A.; Ptak, A.; Stern, D. +9 more
We present results from four new broadband X-ray observations of the extreme ultraluminous X-ray source Holmberg IX X-1 ({L}{{X}}> {10}40 erg s-1), performed by Suzaku and NuSTAR in coordination. Combined with the archival data, we now have broadband observations of this remarkable source from six separate epoch…
Uniform Contribution of Supernova Explosions to the Chemical Enrichment of Abell 3112 out to R 200
Miller, Eric D.; Bulbul, Esra; Smith, Randall K. +5 more
The spatial distribution of the metals residing in the intra-cluster medium (ICM) of galaxy clusters records all the information on a cluster’s nucleosynthesis and chemical enrichment history. We present measurements from a total of 1.2 Ms Suzaku XIS and 72 ks Chandra observations of the cool-core galaxy cluster Abell 3112 out to its virial radius…
Toward the Understanding of the Physical Origin of Recombining Plasma in the Supernova Remnant IC 443
Uchida, Hiroyuki; Tsuru, Takeshi Go; Tanaka, Takaaki +2 more
We perform a spatially resolved spectroscopic analysis of X-ray emission from the supernova remnant (SNR) IC 443 with Suzaku. All of the spectra are well reproduced by a model consisting of a collisional ionization equilibrium (CIE) and two recombining plasma (RP) components. Although previous X-ray studies found an RP in the northeastern region, …
Shocks and Tides Quantified in the “Sausage” Cluster, CIZA J2242.8+5301 Using N-body/Hydrodynamical Simulations
Broadhurst, T.; Molnar, S. M.
The colliding cluster, CIZA J2242.8+5301, displays a spectacular, almost 2 Mpc long shock front with a radio based Mach number M≃ 5, that is puzzlingly large compared to the X-ray estimate of M≃ 2.5. The extent to which the X-ray temperature jump is diluted by cooler unshocked gas projected through the cluster currently lacks quantification. Here …
The X-Ray Reflection Spectrum of the Radio-loud Quasar 4C 74.26
Harrison, F. A.; Zhang, W. W.; Fabian, Andrew C. +11 more
The relativistic jets created by some active galactic nuclei are important agents of AGN feedback. In spite of this, our understanding of what produces these jets is still incomplete. X-ray observations, which can probe the processes operating in the central regions in the immediate vicinity of the supermassive black hole, the presumed jet launchi…
A Redshift Survey of the Nearby Galaxy Cluster Abell 2199: Comparison of the Spatial and Kinematic Distributions of Galaxies with the Intracluster Medium
Hwang, Ho Seong; Park, Changbom; Song, Hyunmi +1 more
We present the results from an extensive spectroscopic survey of the central region of the nearby galaxy cluster Abell 2199 (A2199) at z = 0.03. By combining 775 new redshifts from the MMT/Hectospec observations with the data in the literature, we construct a large sample of 1624 galaxies with measured redshifts at R< 30\prime , whic…