Search Publications
An Angle-dependent Synchrotron Self-Compton Model for Relativistic Jet Sources
Böttcher, M.; Jamil, O.
We report on the development of a numerical code to calculate the angle-dependent synchrotron + synchrotron self-Compton radiation from relativistic jet sources with partially ordered magnetic fields and anisotropic particle distributions. Using a multi-zone radiation transfer approach, we can simulate magnetic-field configurations ranging from pe…
AMUSE-Virgo. III. Mid-infrared Photometry of Early-type Galaxies and Limits on Obscured Nuclear Emission
Treu, Tommaso; Antonucci, Robert; Gallo, Elena +3 more
We complete our census of low-level nuclear activity in Virgo Cluster early-type galaxies by searching for obscured emission using Spitzer Space Telescope mid-infrared (MIR) imaging at 24 µm. Of a total sample of 95 early-type galaxies, 53 objects are detected, including 16 showing kiloparsec-scale dust in optical images. One-dimensional and…
A Second Neutron Star in M4?
Thompson, Ian B.; Kaluzny, J.; Rozanska, A. +2 more
We show that the optical counterpart of the X-ray source CX 1 in M4 is a ~20th magnitude star, located in the color-magnitude diagram on (or very close to) the main sequence of the cluster, and exhibiting sinusoidal variations of the flux. We find the X-ray flux to be also periodically variable, with X-ray and optical minima coinciding. Stability …
On the X-Ray Emission Mechanisms of the Persistent Source and Very Low Fluence Bursts of SGR J0501+4516
Kouveliotou, Chryssa; Göǧüş, Ersin; Lin, Lin +1 more
We present here a detailed spectral study of the X-ray emission of the persistent source and the low-fluence bursts of SGR J0501+4516 observed during a deep XMM-Newton observation near the peak of its 2008 outburst. For the persistent emission, we employ a physically motivated continuum emission model and spectroscopically determine important sour…
Giant H II Regions in M101. I. X-Ray Analysis of Hot Gas
Feng, Li; Chu, You-Hua; Wang, Q. Daniel +4 more
We performed a Chandra X-ray study of three giant H II regions (GHRs), NGC 5461, NGC 5462, and NGC 5471, in the spiral galaxy M101. The X-ray spectra of the three GHRs all contain a prominent thermal component with a temperature of ~0.2 keV. In NGC 5461, the spatial distribution of the soft (<1.5 keV) X-ray emission is generally in agreement wi…
Post-starburst Tidal Tails in the Archetypical Ultra Luminous Infrared Galaxy Arp 220
Murayama, T.; Taniguchi, Y.; Kajisawa, M. +6 more
We present our new deep optical imaging and long-slit spectroscopy for Arp 220, the archetypical ultra luminous infrared galaxy in the local universe. Our sensitive Hα imaging has newly revealed large-scale Hα absorption, i.e., post-starburst regions in this merger. One is found in the eastern superbubble and the other is in the two tidal tails th…
Unusual Carbonaceous Dust Distribution in PN G095.2+00.7
Onaka, Takashi; Matsuura, Mikako; Sakon, Itsuki +5 more
We investigate the polycyclic aromatic hydrocarbon (PAH) features in the young Galactic planetary nebula PN G095.2+00.7 based on mid-infrared observations. The near- to mid-infrared spectra obtained with the AKARI/IRC and the Spitzer/IRS show the PAH features as well as the broad emission feature at 12 µm usually seen in proto-planetary nebu…
Anomalous Anisotropic Cross-correlations between WMAP CMB Maps and SDSS Galaxy Distribution and Implications on the Dark Flow Scenario
Chen, Xuelei; Zhang, Pengjie; Li, Zhigang
We search for the dark flow induced diffuse kinetic Sunyaev-Zel'dovich (kSZ) effect through CMB-galaxy cross-correlation. Such angular correlation is anisotropic, with a unique cos (θDF) angular dependence, and hence can be distinguished from other components. Here, θDF is the angle between the opposite dark flow direction an…
A Precise Physical Orbit for the M-dwarf Binary Gliese 268
Queloz, D.; Ségransan, D.; Demory, B. -O. +11 more
We report high-precision interferometric and radial velocity (RV) observations of the M-dwarf binary Gl 268. Combining measurements conducted using the IOTA interferometer and the ELODIE and Harvard Center for Astrophysics RV instruments leads to a mass of 0.22596 ± 0.00084 M ⊙ for component A and 0.19230 ± 0.00071 M ⊙ for co…
Inverse Compton Scattering Model for X-Ray Emission of the Gamma-Ray Binary LS 5039
Yamaguchi, M. S.; Takahara, F.
We propose a model for the gamma-ray binary LS 5039 in which the X-ray emission is due to the inverse Compton (IC) process instead of the synchrotron radiation. Although the synchrotron model has been discussed in previous studies, it requires a strong magnetic field which leads to a severe suppression of the TeV gamma-ray flux in conflict with H.…