Search Publications
Relativistic Lines and Reflection from the Inner Accretion Disks Around Neutron Stars
Miller, Jon M.; Cackett, Edward M.; Wijnands, Rudy +6 more
A number of neutron star low-mass X-ray binaries (LMXBs) have recently been discovered to show broad, asymmetric Fe K emission lines in their X-ray spectra. These lines are generally thought to be the most prominent part of a reflection spectrum, originating in the inner part of the accretion disk where strong relativistic effects can broaden emis…
Fermi Large Area Telescope View of the Core of the Radio Galaxy Centaurus A
Ozaki, M.; Caraveo, P. A.; Frailis, M. +195 more
We present γ-ray observations with the Large Area Telescope (LAT) on board the Fermi Gamma-Ray Space Telescope of the nearby radio galaxy Centaurus A (Cen A). The previous EGRET detection is confirmed, and the localization is improved using data from the first 10 months of Fermi science operation. In previous work, we presented the detection of th…
Discovery of Ultra-fast Outflows in a Sample of Broad-line Radio Galaxies Observed with Suzaku
Cappi, M.; Ballo, L.; Tombesi, F. +5 more
We present the results of a uniform and systematic search for blueshifted Fe K absorption lines in the X-ray spectra of five bright broad-line radio galaxies observed with Suzaku. We detect, for the first time in radio-loud active galactic nuclei (AGNs) at X-rays, several absorption lines at energies greater than 7 keV in three out of five sources…
Efficient Cosmic Ray Acceleration, Hydrodynamics, and Self-Consistent Thermal X-Ray Emission Applied to Supernova Remnant RX J1713.7-3946
Raymond, John; Slane, Patrick; Ellison, Donald C. +1 more
We model the broadband emission from supernova remnant (SNR) RX J1713.7-3946 including, for the first time, a consistent calculation of thermal X-ray emission together with non-thermal emission in a nonlinear diffusive shock acceleration model. Our model tracks the evolution of the SNR including the plasma ionization state between the forward shoc…
Suzaku Observation of A1689: Anisotropic Temperature and Entropy Distributions Associated with the Large-scale Structure
Fukazawa, Yasushi; Nakazawa, Kazuhiro; Ohashi, Takaya +7 more
We present results of new, deep Suzaku X-ray observations (160 ks) of the intracluster medium (ICM) in A1689 out to its virial radius, combined with complementary data sets of the projected galaxy distribution obtained from the SDSS catalog and the projected mass distribution from our recent comprehensive weak and strong lensing analysis of Subaru…
Expansion Velocity of Ejecta in Tycho's Supernova Remnant Measured by Doppler Broadened X-ray Line Emission
Katsuda, Satoru; Kunieda, Hideyo; Makishima, Kazuo +10 more
We show that the expansion of ejecta in Tycho's supernova remnant (SNR) is consistent with a spherically symmetric shell, based on Suzaku measurements of the Doppler broadened X-ray emission lines. All of the strong Kα line emissions show broader widths at the center than at the rim, while the centroid energies are constant across the remnant (exc…
Galaxy Clusters at the Edge: Temperature, Entropy, and Gas Dynamics Near the Virial Radius
O'Shea, Brian W.; Burns, Jack O.; Skillman, Samuel W.
Recently, Suzaku has produced temperature and entropy profiles, along with profiles of gas density, gas fraction, and mass, for multiple galaxy clusters out to approximately the virial radius. In this paper, we compare these novel X-ray observations with results from N-body + hydrodynamic adaptive mesh refinement cosmological simulations using the…
Dark Matter Search Using Chandra Observations of Willman 1 and a Spectral Feature Consistent with a Decay Line of a 5 keV Sterile Neutrino
Loewenstein, Michael; Kusenko, Alexander
We report the results of a search for an emission line from radiatively decaying dark matter in the Chandra X-ray Observatory spectrum of the ultra-faint dwarf spheroidal galaxy Willman 1. 99% confidence line flux upper limits over the 0.4-7 keV Chandra bandpass are derived and mapped to an allowed region in the sterile neutrino mass-mixing angle …
Broadband Study with Suzaku of the Magnetar Class
Hurley, K.; Rea, N.; Enoto, T. +3 more
Broadband (0.8-70 keV) spectra of the persistent X-ray emission from nine magnetars were obtained with Suzaku, including three objects in apparent outburst. The soft X-ray component was detected from all of them, with a typical blackbody temperature of kT ~ 0.5 keV, while the hard-tail component, dominating above ~10 keV, was detected at ~1 mCrab …
Quiescent X-ray Emission From Cen X-4: A Variable Thermal Component
Miller, Jon M.; Cackett, Edward M.; Wijnands, Rudy +1 more
The nearby neutron star low-mass X-ray binary, Cen X-4, has been in a quiescent state since its last outburst in 1979. Typically, quiescent emission from these objects consists of thermal emission (presumably from the neutron star surface) with an additional hard power-law tail of unknown nature. Variability has been observed during quiescence in …