J/A+A/536/A84 X-ray variability of AGN (Vagnetti+, 2011)
Ensemble X-ray variability of active galactic nuclei from serendipitous source
catalogues.
Vagnetti F., Turriziani S., Trevese D.
<Astron. Astrophys., 536, A84 (2011)>
=2011A&A...536A..84V 2011A&A...536A..84V
ADC_Keywords: Surveys ; Active gal. nuclei ; X-ray sources
Keywords: surveys - galaxies: active - quasars: general - X-rays: galaxies
Abstract:
The X-ray variability of the active galactic nuclei (AGN) has been
most often investigated with studies of individual, nearby sources,
and only a few ensemble analyses have been applied to large samples
in wide ranges of luminosity and redshift.
We aim to determine the ensemble variability properties of two
serendipitously selected AGN samples extracted from the catalogues of
XMM-Newton and Swift, with redshift between ∼0.2 and ∼4.5, and X-ray
luminosities, in the 0.5-4.5keV band, between ∼1043erg/s and
∼1046erg/s.
We used the structure function (SF), which operates in the time
domain, and allows for an ensemble analysis even when only a few
observations are available for individual sources and the power
spectral density (PSD) cannot be derived. The SF is also more
appropriate than fractional variability and excess variance, because
these parameters are biased by the duration of the monitoring time
interval in the rest-frame, and therefore by cosmological time
dilation.
Description:
For XMM, we use the version presently available is 2XMMi-DR3, the
latest incremental update of the second version of the catalogue, with
observations made between 2000 February 3 and 2008 October 08.
For Swift, we used the preliminary version S3XGF catalogue, comprising
GRB fields observed from January 2005 to June 2007.
The selected sources was cross-correlated it with the DR7 edition of
the SDSS Quasar Catalogue (Schneider et al., 2010, Cat. VII/260) to
obtain redshifts and spectral classifications.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 61 412 XMM-Newton sample
table2.dat 60 27 Swift sample
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See also:
IX/41 : XMM-Newton Serendipitous Source Cat. 2XMMi-DR3 (XMM-SSC, 2010)
VII/260 : The SDSS-DR7 quasar catalog (Schneider+, 2010)
J/A+A/528/A122 : SwiftFT catalog (Puccetti+, 2011)
Byte-by-byte Description of file: table1.dat
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Bytes Format Units Label Explanations
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1- 3 I3 --- Seq [1/412] Sequential number, within the table
5- 9 A5 --- --- [2XMM 2XMMi]
11- 26 A16 --- 2XMM 2XMM or 2XMMi designation (JHHMMSS.s+DDMMSS)
28- 33 F6.4 --- z Redshift
35- 36 I2 --- Nep Number of observation epochs
38- 43 F6.2 [mW/m2] logfX X-ray flux in the 0.5-4.5keV band
45- 49 F5.2 [10-7W] logLX X-ray luminosity in the 0.5-4.5keV band
51- 55 F5.2 [d] logtmin Minimum lag τmin between any two epochs
of the light curve in the source rest-frame
57- 61 F5.2 [d] logtmax Maximum lag τmax between any two epochs
of the light curve in the source rest-frame
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Byte-by-byte Description of file: table2.dat
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Bytes Format Units Label Explanations
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1- 3 I3 --- Seq [1/27] Sequential number, within the table
5- 11 A7 --- --- [SWIFTFT]
13- 28 A16 --- SWIFTFT SWIFTFT designation (JHHMMSS.s+DDMM.m)
30- 33 F4.2 --- z Redshift
35- 36 I2 --- Nbin Number of time bins
38- 43 F6.2 [mW/m2] logfX X-ray flux in the band 0.5-4.5keV
45- 49 F5.2 [10-7W] logLX X-ray luminosity in the band 0.5-4.5keV
51- 60 A10 --- GRB GRB field
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History:
From electronic version of the journal
(End) Patricia Vannier [CDS] 21-Feb-2012