J/A+A/497/81 Variability-selected AGN in CDFS (Boutsia+, 2009)
Spectroscopic follow-up of variability-selected active galactic nuclei in the
Chandra Deep Field South.
Boutsia K., Leibundgut B., Trevese D., Vagnetti F.
<Astron. Astrophys., 497, 81-95 (2009)>
=2009A&A...497...81B 2009A&A...497...81B
ADC_Keywords: Surveys ; Active gal. nuclei ; X-ray sources ; Redshifts
Keywords: surveys - galaxies: active - quasars: general - X-rays: galaxies
Abstract:
Supermassive black holes with masses of 105-109M☉ are
believed to inhabit most, if not all, nuclear regions of galaxies, and
both observational evidence and theoretical models suggest a scenario
where galaxy and black hole evolution are tightly related. Luminous
AGNs are usually selected by their non-stellar colours or their X-ray
emission. Colour selection cannot be used to select low-luminosity
AGNs, since their emission is dominated by the host galaxy. Objects
with low X-ray to optical ratio escape even the deepest X-ray surveys
performed so far. In a previous study we presented a sample of
candidates selected through optical variability in the Chandra Deep
Field South, where repeated optical observations were performed in the
framework of the STRESS supernova survey.
The analysis is devoted to breaking down the sample in AGNs, starburst
galaxies, and low-ionisation narrow-emission line objects, to
providing new information about the possible dependence of the
emission mechanisms on nuclear luminosity and black-hole mass, and
eventually studying the evolution in cosmic time of the different
populations.
Description:
We obtained new optical spectroscopy for a sample of variability
selected candidates with the ESO NTT telescope. We analysed the new
spectra, together with those existing in the literature and studied
the distribution of the objects in U-B and B-V colours, optical and
X-ray luminosity, and variability amplitude.
The observing run on La Silla took place from the 1st to the 5th of
November 2007.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 59 27 Catalogue of variable sources observed during
our spectroscopic follow-up
table2.dat 162 68 Catalogue of extragalactic variable objects in
the AXAF field with spectroscopic redshift
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See also:
J/A+A/488/73 : Variability-selected AGN in Chandra DFS (Trevese+, 2008)
Byte-by-byte Description of file: table1.dat
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Bytes Format Units Label Explanations
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1- 3 I3 --- [TBV2008] Sequential number
5- 6 I2 h RAh Right ascension (J2000)
8- 9 I2 min RAm Right ascension (J2000)
11- 15 F5.2 s RAs Right ascension (J2000)
17 A1 --- DE- Declination sign (J2000)
18- 19 I2 deg DEd Declination (J2000)
21- 22 I2 arcmin DEm Declination (J2000)
24- 27 F4.1 arcsec DEs Declination (J2000)
29- 33 F5.2 mag Vmag V magnitude
35- 38 F4.2 mag AVmag Vmin-Vmax_ amplitude
40- 43 I4 s Texp Exposure time
45- 48 F4.2 --- Airmass Airmass
50- 53 F4.2 --- z ? Redshift
55- 59 A5 --- Cl Spectroscopic class (G1)
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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 --- [TBV2008] Sequential number
5- 6 I2 h RAh Right ascension (J2000)
8- 9 I2 min RAm Right ascension (J2000)
11- 15 F5.2 s RAs Right ascension (J2000)
17 A1 --- DE- Declination sign (J2000)
18- 19 I2 deg DEd Declination (J2000)
21- 22 I2 arcmin DEm Declination (J2000)
24- 27 F4.1 arcsec DEs Declination (J2000)
29- 33 F5.2 mag Vmag1 V magnitude (from paper I, J/A+A/488/73)
35- 39 F5.3 mag sig Standard deviation of the light curve
(from paper I, J/A+A/488/73)
41- 44 F4.1 mag sig* Normalised standard deviation of the
light curve (1)
46- 64 A19 --- EIS EIS name (JHHMMSS.ss+DDMMSS.s)
66- 70 F5.2 mag Vmag ? EIS V magnitude, AB system
72- 76 F5.2 mag Rmag ? EIS R magnitude, AB system
78- 82 F5.2 mag (U-B) ? EIS U-B colour index, AB system
84- 88 F5.2 mag (B-V) ? EIS B-V colour index, AB system
90- 93 F4.2 --- S/G ? EIS Stellarity index in the V band
95- 99 I5 --- [WDK2001] ? COMBO-17 identification number
101-103 A3 --- CCl COMBO class (Wolf et al. 2004,
Cat. II/253) (2)
105-109 F5.3 --- z ? Spectroscopic redshift
111-115 A5 --- Cl Spectroscopic class (G1)
118-120 I3 --- [LBA2005] ? X-ray identification from Lehmer et al.
(2005, Cat. J/ApJS/161/21)
122 A1 --- l_FX Limit flag on FX
123-130 E8.3 mW/m2 FX ? X-ray flux in the 2-8keV band
132 A1 --- l_logLX Limit flag on logLX
133-137 F5.2 [10-7W] logLX ? X-ray luminosity in the 2-8keV band
139-143 F5.2 [10-7W] logLR ? R-band luminosity
145 A1 --- l_log(X/O) Limit flag on log(X/O)
146-151 F6.3 [-] log(X/O) ? X-ray-to-optical flux ratio
153-162 A10 --- Notes Notes (3)
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Note (1): Defined as: sigma*=[sigma-s(V)]/[S(sigma(V))]
where s(V) and S(sigma(V)) are the ensemble average and standard
deviation of sigma, the rms variation.
Note (2): COMBO-class as follows:
G = galaxy
Q = QSO
S = star
U = unclear
Note (3): Notes as follows:
c = Observed in our spectroscopic follow-up
d = Spectroscopic redshift from Szokoly et al. (2004, Cat. J/ApJS/155/271)
e = From Ravikumar et al. (2007, Cat. J/A+A/465/1099)
f = From Grazian et al. (2006, cat. J/A+A/449/951)
g = From Le Fevre et al. (200, Cat. J/A+A/428/1043)
h = From Popesso et al. (2009A&A...494..443P 2009A&A...494..443P)
s = From Treister et al. (2009ApJ...693.1713T 2009ApJ...693.1713T)
k = Our estimate from the CDFS intensity maps
l = Our estimate from the ECDFS intensity maps
m = Extra-nuclear (Lehmer et al., 2006AJ....131.2394L 2006AJ....131.2394L)
n = XID from Giacconi et al. (2002, Cat. J/ApJS/139/369)
p = Detected in radio by Kellermann et al. (2008, Cat. J/ApJS/179/71)
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Global notes:
Note (G1): Spectroscopic class as follows:
BLAGN = Broad Line AGN
NELG = Narrow Emission Line Galaxy
Gal = galaxy
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History:
From electronic version of the journal
References:
Trevese et al., Paper I 2008A&A...488...73T 2008A&A...488...73T, Cat. J/A+A/488/73
(End) Patricia Vannier [CDS] 24-Aug-2009