J/A+A/551/A95 Reduced co-added LETGS spectrum of Ark 564 (Ramirez, 2013)
Chandra LETGS observation of the variable NLS1 galaxy Ark 564.
Ramirez J.M.
<Astron. Astrophys. 551, A95 (2013)>
=2013A&A...551A..95R 2013A&A...551A..95R
ADC_Keywords: Galaxies, Seyfert ; X-ray sources ; Spectroscopy
Keywords: galaxies: Seyfert - line: identification - quasars: absorption lines
Abstract:
We present an analysis of the 100ks X-ray spectrum of the narrow-line
Seyfert 1 Galaxy Ark 564, taken with the Low Energy Transmission
Grating Spectrometer (LETGS) on board Chandra. Using chisquare
statistics, several continuum models of the time-averaged spectrum of
this object are compared, obtaining a semi-empirical solution for the
description of the intrinsic emission continuum and a physical
solution for the intrinsic absorption of the system. We find that the
0.1-10keV spectrum can be well described by a power law plus two
thermal components that account for the soft step. We are also able to
detect and measure several narrow, unresolved absorption lines arising
from highly ionized species of C, N, O, and Fe. The material seems to
have a velocity consistent with the systemic velocity of the galaxy.
This piece of evidence, in addition to the very low observed column
density of Nh∼1020cm-2, is in good agreement with the scenario of
a transverse biconical outflow with a gas density of n<3x1012cm-3
at distances beyond the broad-line region r>10lt-days, but a dust
torus origin cannot be ruled out.
Description:
This is the 1-D LETGS (Low Energy Transmission Grating Spectrometer on
board Chandra) spectrum of Ark 564 observed in April 2008, ObsID: 09151.
Objects:
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RA (2000) DE Designation(s)
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22 42 39.31 +29 43 31.6 Ark 564 = UGC 12163
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File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
spectrum.dat 54 1533 LETGS (Low Energy Transmission Grating in Chandra,
0.07-0.2keV) 100ks spectrum of Ark 564
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See also:
B/chandra : The Chandra Archive Log (CXC, 1999-2012)
V/138 : Cross-matched radio/infrared/X-ray sources (Combi+, 2011)
VII/173 : Catalogue of Seyfert Galaxies (Lipovetsky+, 1988)
J/ApJ/590/73 : RASS AGN sample. II. (Xu+, 2003)
J/A+A/418/465 : Mid-infrared and hard X-ray emission in AGN (Lutz+, 2004)
J/A+A/495/421 : Catalog of AGN in XMM-Newton archive (CAIXA) (Bianchi+, 2009)
J/ApJ/713/L11 : X-ray properties of Seyfert 1 galaxies (Zhou+, 2010)
J/AJ/141/129 : Chandra Transmission Grating Data Catalog (Huenemoerder+, 2011)
Byte-by-byte Description of file:spectrum.dat
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Bytes Format Units Label Explanations
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2- 10 F9.5 0.1nm lambda [1.275/122.107] Wavelength (Å)
15- 21 F7.5 0.1nm e_lambda Error on lambda
25- 32 F8.5 10ct/s/nm counts Counts per seconds per spectral bin (1Å)
37- 43 F7.5 10ct/s/nm e_counts Errors on counts
48- 54 F7.5 10ct/s/nm Mcounts Best fit physical model
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Acknowledgements:
Jose M. Ramirez, josem(at)ivic.gob.ve
(End) Jose M. Ramirez [IVIC, Venezuela] 06-Feb-2013