Search Publications
The Jet Heated X-Ray Filament in the Centaurus A Northern Middle Radio Lobe
Hardcastle, M. J.; Croston, J. H.; Birkinshaw, M. +6 more
We present results from a 40 ks XMM-Newton observation of the X-ray filament coincident with the southeast edge of the Centaurus A Northern Middle Radio Lobe (NML). We find that the X-ray filament consists of five spatially resolved X-ray knots embedded in a continuous diffuse bridge. The spectrum of each knot is well fitted by a thermal model wit…
Suzaku View of the Swift/BAT Active Galactic Nuclei. I. Spectral Analysis of Six Active Galactic Nuclei and Evidence for Two Types of Obscured Population
Ueda, Yoshihiro; Terashima, Yuichi; Mushotzky, Richard +2 more
We present a systematic spectral analysis with Suzaku of six active galactic nuclei (AGNs) detected in the Swift/BAT hard X-ray (15-200 keV) survey: Swift J0138.6-4001, J0255.2-0011, J0350.1-5019, J0505.7-2348, J0601.9-8636, and J1628.1-5145. This is considered to be a representative sample of new AGNs without X-ray spectral information before the…
Tools for Dissecting Supernova Remnants Observed with Chandra: Methods and Application to the Galactic Remnant W49B
Ramirez-Ruiz, E.; Jeltema, T. E.; Lopez, L. A. +1 more
We introduce methods to quantify the X-ray morphologies of supernova remnants (SNRs) observed with the Chandra X-ray Telescope. These include a power-ratio technique to measure morphological asymmetries, correlation-length analysis to probe chemical segregation and distribution, and wavelet-transform analysis to quantify the X-ray substructure. We…
Temperature Tomography of a Coronal Sigmoid Supporting the Gradual Formation of a Flux Rope
Young, Peter R.; Tripathi, Durgesh; Kliem, Bernhard +2 more
Multiwavelength observations of a sigmoidal (S-shaped) solar coronal source by the EUV Imaging Spectrometer and the X-Ray Telescope aboard the Hinode spacecraft and by the EUV Imager aboard STEREO are reported. The data reveal the coexistence of a pair of J-shaped hot arcs at temperatures T>2 MK with an S-shaped structure at somewhat lower temp…
The Dusty Nuclear Torus in NGC 4151: Constraints from Gemini Near-Infrared Integral Field Spectrograph Observations
Storchi-Bergmann, Thaisa; Riffel, Rogemar A.; McGregor, Peter J.
We have used a near-infrared (near-IR) nuclear spectrum (covering the Z, J, H, and K bands) of the nucleus of NGC 4151 obtained with the Gemini Near-Infrared Integral Field Spectrograph (NIFS) and adaptive optics, to isolate and constrain the properties of a near-IR unresolved nuclear source whose spectral signature is clearly present in our data.…
Hydrostatic Gas Constraints on Supermassive Black Hole Masses: Implications for Hydrostatic Equilibrium and Dynamical Modeling in a Sample of Early-type Galaxies
Gebhardt, Karl; Humphrey, Philip J.; Buote, David A. +2 more
We present new mass measurements for the supermassive black holes (SMBHs) in the centers of three early-type galaxies. The gas pressure in the surrounding, hot interstellar medium (ISM) is measured through spatially resolved spectroscopy with the Chandra X-ray Observatory, allowing the SMBH mass (M BH) to be inferred directly under the …
X-ray Spectroscopy of the Core of the Perseus Cluster with Suzaku: Elemental Abundances in the Intracluster Medium
Fabian, A. C.; Mitsuda, K.; Sanders, J. S. +7 more
The results from Suzaku observations of the central region of the Perseus cluster are presented. Deep exposures with the X-ray Imaging Spectrometer provide high-quality X-ray spectra from the intracluster medium. X-ray lines from helium-like Cr and Mn have been detected significantly for the first time in clusters. In addition, elemental abundance…
A Statistical Study of Hard X-Ray Footpoint Motions in Large Solar Flares
Krucker, Säm; Ip, W. H.; Lin, R. P. +2 more
A statistical analysis of the temporal evolution of hard X-ray (HXR) footpoint motions in 27 M- and X-class solar flares observed by the Reuven Ramaty High Energy Solar Spectroscopic Imager is presented. Extreme UV images from TRACE and SOHO/EIT, Hα images, and magnetograms from SOHO/MDI are used to put the HXR footpoint motions in context of flar…
Long-Term Stability of Nonthermal X-Ray Modulation in the Gamma-Ray Binary LS 5039
Takahashi, Tadayuki; Uchiyama, Yasunobu; Tanaka, Takaaki +1 more
We report on long-term stability of X-ray modulation apparently synchronized with an orbital period of 3.9 days in the γ-ray binary LS 5039. Recent observations with the Suzaku satellite in the year 2007, which continuously covered more than one orbital period, have provided us with detailed characterization of X-ray flux and spectral shape as a f…
Color Distributions, Number, and Mass Densities of Massive Galaxies at 1.5 < z < 3: Comparing Observations with Merger Simulations
van Dokkum, Pieter G.; Franx, Marijn; Labbé, Ivo +9 more
We present a comparison between the observed color distribution, number, and mass density of massive galaxies at 1.5 < z < 3 and a model by Hopkins et al. that relates the quasar and galaxy population on the basis of gas-rich mergers. In order to test the hypothesis that quiescent red galaxies are formed after a gas-rich merger involving qua…