The Detection of Circumnuclear X-ray Emission from the Seyfert Galaxy NGC 3516
| Authors:
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George, I.M.2,3,
Turner, T.J.2,3,
Netzer, H.1,
Kraemer, S.5,
Ruiz, J.,
Chelouche, D.1,
Crenshaw, D.M.4,
Yaqoob, T.,
Nandra, K.2,6
Mushotzky, R.F.,
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| Affiltns:
|
1Tel Aviv University,
2 LHEA,
NASA/GSFC,
3 JCA, UMBC
4 Georgia State University,
5 Catholic University of America,
6 USRA
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| Journal:
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ApJ
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| Publn Date:
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in press
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Summary
We present the first high-resolution, X-ray image of the circumnuclear regions of the Seyfert 1 galaxy NGC 3516,
using the Chandra X-ray Observatory (CXO).
All three of the CXO observations reported were performed with one
of the two grating assemblies in place, and here we restrict our
analysis to undispersed photons (i.e. those detected
in the zeroth-order). A previously-unknown X-ray source is detected
approx 6 arcsec (1.1 h75-1 kpc) NNE
of the nucleus (position angle approx 29 degrees)
which we designate CXOU 110648.1+723412. Its spectrum can be
characterized as a power law with a photon index Gamma ~ 1.8-2.6, or as thermal emission with a temperature
kT~0.7-3 keV. Assuming a location within NGC 3516, isotropic emission implies a luminosity
L ~ 2-8e39
h75-2 erg s-1
in the 0.4--2 keV band. If due to a single point source, the object is super-Eddington for a
1.4 M_sun neutron star. However, multiple sources or a small, extended source
cannot be excluded using the current
data. Large-scale extended X-ray emission is also detected out to ~10 arcsec
(~1.7 h75-1 kpc) from the
nucleus to the NE and SW, and is approximately aligned with the
morphologies of the radio emission and extended
narrow emission line region (ENLR). The mean luminosity of this emission
is 1--5e37 h75-2 erg s-1 arcsec-2,
in the 0.4--2 keV band. Unfortunately the current data cannot usefully constrain its spectrum. These
results are consistent with earlier suggestions of circumnuclear X-ray emission in NGC 3516. If the extended
emission is due to scattering of the nuclear X-ray continuum, then
the pressure in the X-ray emitting gas is at least
two orders of magnitude too small to provide the confining medium for the ENLR clouds.
Figures:
Fig1
Fig2
Fig3
Full Text
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See Also
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