Search Publications
Disentangling the gamma-ray emission of NGC 1275 and that of the Perseus cluster
Colafrancesco, S.; Giommi, P.; Marchegiani, P.
Context. The Gamma-ray emission from galaxy clusters hosting active galaxies is a complex combination of diffuse and point-like emission features with different spectral and spatial properties.
Aims: We discuss in details the case of the Perseus cluster containing the radio-galaxy NGC 1275 that has been recently detected as a bright gamma-ray…
The Impact of New EUV Diagnostics on CME-Related Kinematics
De Pontieu, Bart; McIntosh, Scott W.; Leamon, Robert J.
We present the application of novel diagnostics to the spectroscopic observation of a Coronal Mass Ejection (CME) on disk by the Extreme Ultraviolet Imaging Spectrometer (EIS) on the Hinode spacecraft. We apply a recently developed line profile asymmetry analysis to the spectroscopic observation of NOAA AR 10930 on 14 - 15 December 2006 to three r…
Low-metallicity Star Formation in High-redshift Galaxies at z ~ 8
Taniguchi, Y.; Trump, J. R.; Shioya, Y.
Based on the recent very deep near-infrared imaging of the Hubble Ultra Deep Field with WFC3 on the Hubble Space Telescope, five groups published the most probable samples of galaxies at z ~ 8, selected by the so-called dropout method or photometric redshift; e.g., Y 105-dropouts (Y 105 - J 125 > 0.8). These stu…
Spectral evolution of bright NS LMXBs with INTEGRAL: an application of the thermal plus bulk Comptonization model
Santangelo, A.; Rodriguez, J.; Bazzano, A. +7 more
Aims: The aim of this work is to investigate in a physical and quantitative way the spectral evolution of bright neutron star low-mass X-ray binaries (NS LMXBs) with special regard to the transient hard X-ray tails.
Methods: We analyzed INTEGRAL data for five sources (GX 5-1, GX 349+2, GX 13+1, GX 3+1, GX 9+1) and built broad-band X-ray …
Can past gamma-ray bursts explain both INTEGRAL and ATIC/PAMELA/Fermi anomalies simultaneously?
Kusenko, Alexander; Calvez, Antoine
Gamma-ray bursts (GRBs) have been invoked to explain both the 511 keV emission from the Galactic bulge and the high-energy positron excess inferred from the ATIC, PAMELA, and Fermi data. While independent explanations can be responsible for these phenomena, we explore the possibility of their common GRB-related origin by modeling the GRB distribut…
Wavelet and R/S analysis of the X-ray flickering of cataclysmic variables
de Martino, D.; Bianchini, A.; Anzolin, G. +1 more
Context. Recently, wavelets and R/S analysis have been used as statistical tools to characterize the optical flickering of cataclysmic variables.
Aims: Here we present the first comprehensive study of the statistical properties of X-ray flickering of cataclysmic variables in order to link them with physical parameters.
Methods: We analyz…
Soft gamma-ray constraints on a bright flare from the Galactic Center supermassive black hole
Genzel, R.; Pantin, E.; Grosso, N. +11 more
Sagittarius A★(SgrA★) is the supermassive black hole residing at the center of the Milky Way. It has been the main target of an extensive multiwavelength campaign we carried out in April 2007. Herein, we report the detection of a bright flare from the vicinity of the horizon, observed simultaneously in X-rays (XMM-Newton/EPIC…
X-ray spectroscopy and photometry of the long-period polar AI Trianguli with XMM-Newton
Burwitz, V.; Beuermann, K.; Dreizler, S. +4 more
Context. The energy balance of cataclysmic variables with strong magnetic fields is a central subject in understanding accretion processes on magnetic white dwarfs. With XMM-Newton, we perform a spectroscopic and photometric study of soft X-ray selected polars during their high states of accretion.
Aims: On the basis of X-ray and optical obse…
The Lorentz force in atmospheres of chemically peculiar stars: 56 Arietis
Shulyak, D.; Kochukhov, O.; Galazutdinov, G. +5 more
Context. The presence of electric currents in the atmospheres of magnetic chemically peculiar (mCP) stars could theoretically constrain the nature and evolution of magnetic field in these stars. The Lorentz force, which is the result of the interaction between the magnetic field and the induced currents, modifies the atmospheric structure and indu…
A Search for Wide Companions to the Extrasolar Planetary System HR 8799
Close, Laird M.; Males, Jared R.
The extrasolar planetary system around HR 8799 is the first multiplanet system ever imaged. It is also, by a wide margin, the highest mass system with >27 Jupiters of planetary mass past 25 AU. This is a remarkable system with no analog in any other known planetary system. In the first part of this paper, we investigated the nature of two faint…