J/other/RMxAA/47.361 AGN activity in isolated SDSS galaxies (Coziol+, 2011)
The nature and origin of Narrow-line AGN Activity in a sample of isolated
SDSS galaxies.
Coziol R., Torres-Papaqui J.P., Plauchu-Frayn I., Islas-Islas J.M.,
Ortega-Minakata R.A., Neri-Larios D.M., Andernach H.
<Rev. Mex. Astron. Astrofis. 47, 361 (2011)>
=2011RMxAA..47..361C 2011RMxAA..47..361C
ADC_Keywords: Galaxies, spectra ; Active gal. nuclei ; Abundances ;
Equivalent widths
Keywords: Galaxies:spectra ; AGN ; Equivalent_widths
Abstract:
We discuss the nature and origin of the nuclear activity observed in
a sample of 292 SDSS narrow-emission-line galaxies, considered to have
formed and evolved in isolation. All these galaxies are spiral like
and show some kind of nuclear activity. The fraction of Narrow Line
AGNs (NLAGNs) and Transition type Objects (TOs; a NLAGN with
circumnuclear star formation) is relatively high, amounting to 64% of
the galaxies. There is a definite trend for the NLAGNs to appear in
early-type spirals, while the star forming galaxies and TOs are found
in later-type spirals. We verify that the probability for a galaxy to
show an AGN characteristic increases with the bulge mass of the galaxy
(Torres-Papaqui et al. 2011), and find evidence that this trend is
really a by-product of the morphology, suggesting that the AGN
phenomenon is intimately connected with the formation process of the
galaxies. Consistent with this interpretation, we establish a strong
connection between the astration rate -- the efficiency with which
the gas is transformed into stars - the AGN phenomenon, and the
gravitational binding energy of the galaxies: the higher the binding
energy, the higher the astration rate and the higher the probability
to find an AGN. The NLAGNs in our sample are consistent with
scaled-down or powered-down versions of quasars and Broad Line AGNs.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
nelg1.dat 134 292 Basic and spectroscopic properties of isolated
Narrow-emission line galaxies (NELG)
(tables 1 and 2)
nelg2.dat 59 292 Masses, gas metallicities and absolute B
magnitudes for the isolated NELGs
(tables 4, 6, 8 and 9)
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Byte-by-byte Description of file: nelg1.dat
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Bytes Format Units Label Explanations
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1- 4 A4 --- --- [SDSS]
6- 24 A19 --- SDSS SDSS object name according to SDSS-DR7
26- 34 F9.5 deg RAdeg Right Ascension (J2000)
36- 44 F9.5 deg DEdeg Declination (J2000)
46- 51 F6.4 --- z redshift according to SDSS-DR7
53- 55 A3 --- morph morphological classification by authors
57- 60 F4.1 kpc rP90 Petrosian radius at 90% from SDSS-DR7
62- 65 F4.2 --- conc concentration index from SDSS-DR7 (1)
67- 71 F5.2 [Lsun] logL.K log of K20-band luminosity from 2MASS
73- 77 F5.2 [yr] logt* log of the mean stellar age of the stellar
populations consistent with STARLIGHT
79- 84 F6.3 [---] lgO3Hb log(O[III]/Hβ) emission-line ratio
86- 91 F6.3 [---] lgN2Ha log(N[II]/Hα) emission-line ratio
93- 95 A3 --- Act Activity Type (2)
97-100 F4.2 [Lsun] lgLHa log(Hα) emission-line luminosity
102-104 I3 km/s sigV ? stellar velocity dispersion
106-110 F5.2 [10-7W] lgL5100 log of 5100-Å continuum luminosity (erg/s)
112-134 A23 --- NEDnam preferred name in NASA/IPAC Extragalactic
Database (NED; ned.ipac.caltech.edu)
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Note (1): ratio of the two Petrosian radii (CI = R(90%)/R(50%))
Note (2): Activity types are:
AGN = active galactic nucleus;
SFG = star forming galaxy;
TO = transition object between the former two
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Byte-by-byte Description of file: nelg2.dat
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Bytes Format Units Label Explanations
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1- 4 A4 --- --- [SDSS]
6- 24 A19 --- SDSS SDSS object name according to SDSS-DR7
26- 30 F5.2 [Msun] lgMblg ? log10 of bulge mass in solar masses
32- 36 F5.2 [Msun] lgMBH ? log10 of black hole mass in solar masses
38- 42 F5.2 [Msun] lgMB log10 of B-band based mass in solar masses (3)
44- 46 A3 --- Act Activity Type (repeated from table1and2)
48- 52 F5.2 [Sun] logOH gas metallicity log(O/H) relative to solar (4)
54- 59 F6.2 mag BMAG absolute magnitude in the B band (5)
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Note (3): see Sect. 3.2 of article for details
Note (4): see Sect. 3.4 of article for details
Note (5): obtained using the Johnson-B band magnitude synthesized from
the SDSS magnitudes (1996AJ....111.1748F 1996AJ....111.1748F). The uncertainty is
of the order of 0.05 mag.
Acknowledgements:
Heinz Andernach, heinz(at)astro.ugto.mx
(End) Heinz Andernach [Universidad de Guanajuato, Mexico] 23-Sep-2011