J/A+A/474/473 XMM-LSS survey: AGN classifications (Garcet+, 2007)
The XMM large scale structure survey: optical vs. X-ray classifications of
active galactic nuclei and the unified scheme.
Garcet O., Gandhi P., Gosset E., Sprimont P.G., Surdej J., Borkowski V.,
Tajer M., Pacaud F., Pierre M., Chiappetti L., Maccagni D., Page M.J.,
Carrera F.J., Tedds J.A., Mateos S., Krumpe M., Contini T., Corral A.,
Ebrero J., Gavignaud I., Schwope A., Le Fevre O., Polletta M., Rosen S.,
Lonsdale C., Watson M., Borczyk W., Vaisanen P.
<Astron. Astrophys., 474, 473-489 (2007)>
=2007A&A...474..473G 2007A&A...474..473G
ADC_Keywords: X-ray sources ; Active gal. nuclei ; QSOs
Keywords: X-ray: galaxies - galaxies: active - surveys -
galaxies: quasars: emission lines
Abstract:
Our goal is to characterize AGN populations by comparing their X-ray
and optical classifications within the framework of the standard
orientation-based unified scheme.
We present a sample of 99 spectroscopically identified (R≤22mag)
X-ray selected point sources in the XMM-LSS survey which are
significantly detected (≥3σ) in the [2-10]keV band with fluxes
between 8x10-15 and 8x10-14erg/s/cm2, and which have more than
80 counts. We have compared their X-ray and optical classifications.
To this end, we performed an X-ray spectral analysis for all of these
99 X-ray sources in order to assess whether they are intrinsically
absorbed or not. The X-ray classification is based on the measured
intrinsic column density. The optical classification is based on the
measured FWHM of the permitted emission lines, the absence of broad
lines being due to obscuration within the framework of the standard
AGN unified scheme.
Description:
We have used the most up-to-date X-ray catalog (Pierre et al., 2007,
Cat. J/MNRAS/382/279) to define a sample of 612 X-ray selected
point-like sources which have both a log-likelihood of detection >20
(this roughly corresponds to >3σ) in the [2-10]keV band (see
Pacaud et al., 2006MNRAS.372..578P 2006MNRAS.372..578P, for full details), and a total
number of counts >80 in the [0.5-10]keV band.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table4.dat 140 99 Optical properties and best-fit parameters from
the X-ray spectral analysis
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See also:
J/MNRAS/382/279 : XMM-LSS catalogue. Version I. (Pierre+, 2007)
Byte-by-byte Description of file: table4.dat
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Bytes Format Units Label Explanations
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1- 2 I2 --- Seq Internal sequence number
3 A1 --- n_Seq [b] b: The spectroscopic redshift is tentative
4- 7 A4 --- --- [XLSS]
9- 24 A16 --- XLSS Source name (Cat. J/MNRAS/382/279)
28- 29 I2 h RAh Right ascension (J2000) (1)
31- 32 I2 min RAm Right ascension (J2000) (1)
34- 37 F4.1 s RAs Right ascension (J2000) (1)
39 A1 --- DE- Declination sign (J2000) (1)
40- 41 I2 deg DEd Declination (J2000) (1)
43- 44 I2 arcmin DEm Declination (J2000) (1)
46- 49 F4.1 arcsec DEs Declination (J2000) (1)
52- 56 F5.2 --- HR Hardness ratio (2)
58- 61 A4 --- XType X-ray classification based on the X-ray
spectral analysis (3)
63- 65 A3 --- OType Optical classification based on the optical
spectra (4)
67- 70 F4.1 mag Rmag ?=99.9 R band magnitude from the SuperCosmos
Sky Survey or from the VVDS
72- 76 F5.2 10-17W/m2 Ftot Flux at [2-10]keV band of the X-ray source
derived from the fitted X-ray model;
78- 82 A5 --- Model Best-fit model (5)
83 A1 --- n_Model [acdef] Note on model (6)
85- 89 F5.3 --- z Spectroscopic redshift derived from the
optical spectra
91- 95 F5.2 [10-7W] logL logarithm of the intrinsic (corrected for
absorption, for both the galactic and the
intrinsic column density) rest-frame
luminosity in the [2-10]keV band
97-102 F6.3 10+22cm-2 NH Best-fit hydrogen column density (7)
104-110 F7.3 10+22cm-2 E_NH ? Error on NH (upper limit) (8)
112-119 F8.5 10+22cm-2 e_NH ? Error on NH (lower limit) (8)
121-125 F5.3 --- Gamma Best-fit value for the photon index Gamma (9)
127-130 F4.2 --- E_Gamma ? Error on Gamma (upper limit) (8)
132-135 F4.2 --- e_Gamma ? Error on Gamma (lower limit) (8)
137-140 F4.2 --- chi2 ? statistic which has been used (10)
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Note (1): Position of the X-ray source coming from the band-merged catalog
from the [0.5-2] and [2-10]keV bands, which has been astrometrically
corrected (Pierre et al., 2007, Cat. J/MNRAS/382/279).
Note (2): Hardness ratio between the hard (H) [2-10]keV band and the soft
(S) [0.5-2]keV band computed using the formula (H-S)/(H+S).
Note (3): X-ray classification in the 2 following classes:
I = NH<1022cm-2
II = NH>1022cm-2
Note (4): Optical classification as follows:
1 = FWHM>1500km/s
2 = FWHM<1500km/s
Note (5): Model as follows:
PL = absorbed power law
PL+BB = absorbed power law plus black body
PL+POW = absorbed power law plus unabsorbed power law
PL+GA = absorbed power law plus an additional emission line
Note (6): Notes as follows:
a = The presence of an emission line around 4.0keV (observed frame)
is required.
c = The presence of an emission line around 0.9keV (observed frame)
is required, but see text.
d = The presence of an emission line at 6.4keV (source rest frame,
consistent with Fe K) is required.
e = The presence of an emission line around 0.7keV (observed frame)
is required, but see text.
f = The presence of an emission line at 6.4keV (source rest frame,
consistent with Fe K) is required.
Note (7): The value 0.026 corresponds to the galactic value and has been
fixed for the values without error bars.
Note (8): Error bar which represents a 90% confidence interval.
Note (9): For some objects we fixed Gamma to a value of 1.9 which is
representative of a type 1 AGN.
Note (10): We present the value for the reduced chi square chi2nu.
Otherwise, Cash statistic has been used.
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History:
* 27-Nov-2007: From electronic version of the journal
* 24-Apr-2008: XLSS names and positions corrected, to be coherent with
Pierre et al. 2007 (Cat. J/MNRAS/382/279)
(End) Patricia Vannier [CDS] 27-Nov-2007