A Strong Excess in the 20-100 keV Emission of NGC 1365

We present a new Suzaku observation of the obscured active galactic nucleus in NGC 1365, revealing an unexpected excess of X-rays above 20 keV of at least a factor ~2 with respect to the extrapolation of the best-fitting 3-10 keV model. Additional Swift-BAT and Integral-IBIS observations show that t...

Full description

Saved in:
Bibliographic Details
Published in:Astrophysical journal. Letters 2009-11, Vol.705 (1), p.L1-L5
Main Authors: Risaliti, G, Braito, V, Laparola, V, Bianchi, S, Elvis, M, Fabbiano, G, Maiolino, R, Matt, G, Reeves, J, Salvati, M, Wang, J
Format: Article
Language:English
Subjects:
07 ISOTOPES AND RADIATION SOURCES
ABSORPTION
ASTROPHYSICS, COSMOLOGY AND ASTRONOMY
COSMIC RAY SOURCES
COSMIC X-RAY SOURCES
DENSITY
ELECTROMAGNETIC RADIATION
EMISSION
ENERGY RANGE
EXTRAPOLATION
GALAXIES
IONIZING RADIATIONS
KEV RANGE
KEV RANGE 10-100
MATHEMATICAL SOLUTIONS
NUMERICAL SOLUTION
PHYSICAL PROPERTIES
RADIATIONS
SORPTION
X RADIATION
X-RAY GALAXIES
Citations: Items that this one cites
Items that cite this one
Online Access:Get full text
Tags: Add Tag
No Tags, Be the first to tag this record!
Description
Summary:We present a new Suzaku observation of the obscured active galactic nucleus in NGC 1365, revealing an unexpected excess of X-rays above 20 keV of at least a factor ~2 with respect to the extrapolation of the best-fitting 3-10 keV model. Additional Swift-BAT and Integral-IBIS observations show that the 20-100 keV is concentrated within ~1.5 arcmin from the center of the galaxy, and is not significantly variable on timescales from days to years. A comparison of this component with the 3-10 keV emission, which is characterized by a rapidly variable absorption, suggests a complex structure of the circumnuclear medium, consisting of at least two distinct components with rather different physical properties, one of which covers >80% of the source with a column density N H ~ 3-4X1024 cm-2. An alternative explanation is the presence of a double active nucleus in the center of NGC 1365.
ISSN:1538-4357
0004-637X
2041-8205
1538-4357
DOI:10.1088/0004-637X/705/1/L1