J/MNRAS/440/476 Low-redshift quasars in SDSS Stripe 82 (Falomo+, 2014)
Low-redshift quasars in the Sloan Digital Sky Survey Stripe 82.
The host galaxies.
Falomo R., Bettoni D., Karhunen K., Kotilainen J.K., Uslenghi M.
<Mon. Not. R. Astron. Soc., 440, 476-493 (2014)>
=2014MNRAS.440..476F 2014MNRAS.440..476F
ADC_Keywords: QSOs ; Redshifts ; Photometry, SDSS
Keywords: galaxies: active - galaxies: nuclei - quasars: general
Abstract:
We present a photometrical and morphological study of the properties
of low-redshift (z<0.5) quasars based on a large and
homogeneous data set of objects derived from the Sloan Digital Sky
Survey Data Release 7. This study over number by a factor of ∼5 any
other previous study of quasi-stellar object (QSO) host galaxies at
low redshift undertaken either on ground or on space surveys. We used
∼400 quasars that were imaged in the SDSS Stripe 82 that is up to
2mag deeper than standard Sloan images. For these quasars we undertake
a study of the host galaxies and of their environments. In this paper
we report the results for the quasar hosts. We are able to detect the
host galaxy for more than 3/4 of the whole data set and characterize
the properties of their hosts. We found that QSO hosts are dominated
by luminous galaxies of absolute magnitude M*-3<M(R)<M*. For the
unresolved objects we computed an upper limit to the host luminosity.
For each well-resolved quasar we are also able to characterize the
morphology of the host galaxy that turn out to be more complex than
what found in previous studies. QSOs are hosted in a variety of
galaxies from pure ellipticals to complex/composite morphologies that
combine spheroids, disc, lens and halo. The black hole (BH) mass of
the quasar, estimated from the spectral properties of the nuclei, is
poorly correlated with the total luminosity of the host galaxy.
However, taking into account only the bulge component we found a
significant correlation between the BH mass and the bulge luminosity
of the host.
Description:
To derive the sample of low-redshift quasars we used the fifth release
of the SDSS quasar catalogue (Schneider et al., 2010AJ....139.2360S 2010AJ....139.2360S,
Cat. VII/260) that is based on the SDSS-DR7 (Abazajian et al.,
2009ApJS..182..543A 2009ApJS..182..543A).
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
tablea1.dat 75 416 The low-redshift QSO sample from SDSS Stripe 82
tablea2.dat 78 416 The properties of QSO host galaxies
tablea3.dat 63 416 The properties of QSO host galaxies
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See also:
VII/260 : The SDSS-DR7 quasar catalog (Schneider+, 2010)
Byte-by-byte Description of file: tablea1.dat
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Bytes Format Units Label Explanations
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1- 3 I3 --- Seq [1/416] Sequential number
5- 22 A18 --- SDSS SDSS designation (HHMMSS.ss+DDMMSS.s)
24- 32 F9.5 deg RAdeg Right ascension (J2000)
34- 41 F8.5 deg DEdeg Declination (J2000)
43- 48 F6.4 --- z [0.1/0.5] Redshift
50- 55 F6.3 mag imag SDSS i magnitude (1)
57- 62 F6.2 mag iMAG Absolute i magnitude
64- 65 I2 --- Nexp [8/75] Number of exposures
67- 70 F4.2 mag Ei Extinction in i band (2)
72- 75 F4.2 arcsec psf [1/1.5] Point spread function
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Note (1): psf magnitude for filter i from SDSS-DR7.
Note (2): Extinction from SDSS DR7 (Abazajian et al. 2009ApJS..182..543A 2009ApJS..182..543A).
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Byte-by-byte Description of file: tablea2.dat
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Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 3 I3 --- Seq [1/416] Sequential number
5- 22 A18 --- SDSS SDSS designation (HHMMSS.ss+DDMMSS.s)
24- 29 F6.4 --- z [0.1/0.5] Redshift
31 A1 --- l_i(N) Limit flag on imagN
32- 36 F5.2 mag i(N) Nucleus SDSS i magnitude
38 A1 --- l_i(h) Limit flag on i(h)
39- 44 F6.3 mag i(h) ?=- Host SDSS i magnitude
46- 49 F4.2 mag e_i(h) ? rms uncertainty on i(h)
51 A1 --- --- [(]
52- 55 F4.2 kpc Re ? Effective nucleus radius
57- 60 F4.2 kpc e_Re ? rms uncertainty on Re
61 A1 --- u_Re [)] Uncertainty flag on Re
63- 67 F5.2 --- chi2ser Sersic fit χ2 value (4)
69- 74 F6.2 --- chi2PSF PSF χ2 value (4)
76 A1 --- Cf [rumx] resolved/unresolved class from
chi2ser/chi2ser fit (G1)
78 A1 --- T [cfn] Type of environment (3)
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Note (3): Type of environment as follows:
c = companions visible in the nearby field
f = features visible
n = no feature visible
Note (4): the comparison of the 2 fits define the resolved,
marginally resolved or unresolved host galaxies (column Cf)
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Byte-by-byte Description of file: tablea3.dat
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Bytes Format Units Label Explanations
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1- 3 I3 --- Seq [1/416] Sequential number
5- 22 A18 --- SDSS SDSS designation (HHMMSS.ss+DDMMSS.s)
24- 28 F5.3 --- z [0.1/0.5] Redshift
30- 33 F4.2 mag Kcor K correction
35- 40 F6.2 mag R(N) ?=- Nucleus absolute R magnitude (k-corrected)
42 A1 --- l_R(h) Limit flag on RMAGH
43- 48 F6.2 mag R(h) ?=- Host absolute R magnitude (k-corrected)
50- 54 F5.2 kpc Re(h) ?=- Effective host galaxy radius
56 A1 --- C [rumx] resolved/unresolved host class (G1)
58- 61 F4.2 --- e [0/1]?=- Ellipticity
63 A1 --- M [edn] Morphology type (5)
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Note (5): Morph type as follows:
e = elliptical dominant
d = disc dominant
n = not classifiable
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Global notes:
Note (G1): Class types:
r = resolved object
u = unresolved
m = marginally resolved
x = discarded object
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History:
From electronic version of the journal
(End) Patricia Vannier [CDS] 19-Jan-2015