J/AJ/150/43 Star formation in active and normal galaxies (Tsai+, 2015)
Star formation in the central regions of active and normal galaxies.
Tsai M., Hwang C.-Y.
<Astron. J., 150, 43 (2015)>
=2015AJ....150...43T 2015AJ....150...43T (SIMBAD/NED BibCode)
ADC_Keywords: Active gal. nuclei ; Galaxies, nearby ; Morphology
Keywords: galaxies: active - galaxies: evolution - galaxies: nuclei -
galaxies: Seyfert - galaxies: star formation
Abstract:
We investigated the properties of the host galaxies of active galactic
nuclei (AGNs). We used radio emission around the nuclei of the host
galaxies to represent AGN activity and used infrared (IR) emission to
represent the star-forming activity and stellar population of the host
galaxies. We determined that active galaxies have higher stellar
masses (SMs) within the central kiloparsec radius than normal galaxies
do independent of the Hubble types of the host galaxies; but both
active and normal galaxies exhibit similar specific star formation
rates (SSFRs), ranging between 10-10.5 and 10-9.5/yr. We find that
the central SM surface density might be used as an indicator to
identify AGNs. We also discovered that certain AGNs exhibit
substantial inner stellar structures in the IR images; most of the
AGNs with inner structures are Seyferts, whereas only a few LINERs
exhibit inner structures. We note that the AGNs with inner structures
show a positive correlation between the radio activity of the AGNs and
the SFRs of the host galaxies, but the sources without inner
structures show a negative correlation between the radio power and the
SFRs. These results might be explained with a scenario of
starburst-AGN evolution. In this scenario, AGN activities are
triggered following a nuclear starburst; during the evolution, AGN
activities are accompanied by SF activity in the inner regions of the
host galaxies; at the final stage of the evolution, the AGNs might
transform into LINERs, exhibiting weak SF activity in the central
regions of the host galaxies.
Description:
We selected 104 active galaxies from the lists of Melendez et al.
(2010MNRAS.406..493M 2010MNRAS.406..493M), Condon et al. 1991 (cat. J/ApJ/378/65), and Ho
& Ulvestad 2001 (cat. J/ApJS/133/77). Most of the sources are
identified as Active Galactic Nuclei (AGNs), and a few of them are
classified as Luminous InfraRed Galaxies (LIRGs). We obtained 3.6 and
8µm infrared images of these galaxies from the Spitzer Archive
(http://sha.ipac.caltech.edu/applications/Spitzer/SHA/) and 8GHz
images from the VLA archive
(http://archive.nrao.edu/archive/archiveimage.html). We also selected
a nearby AGN sub-sample containing 21 radio-selected AGNs for further
spatial analysis. We selected 25 nearby AGNs exhibiting no detected
radio emission in order to compare with the results of the
radio-selected sources.
For comparison, we also selected normal galaxies with distances less
than 15Mpc from the catalog of Tully 1994 (see cat. VII/145). We only
selected the galaxies that have Spitzer archive data and are not
identified as AGNs in either the Veron-Cetty & Veron 2006 (see cat.
VII/258) AGN catalog or in the NED database
(http://ned.ipac.caltech.edu/).
Our results for the radio-selected and the non-radio-selected active
galaxies are listed in Table1, and those for the normal galaxies are
listed in Table2.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 96 129 List of active galaxies
table2.dat 61 119 List of nearby normal galaxies
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See also:
VII/145 : Nearby Galaxies Catalogue (NBG) (Tully 1988)
J/ApJS/133/77 : VLA radio continuum survey of Seyfert galaxies (Ho+, 2001)
J/ApJ/378/65 : 8.4GHz observations of compact starbursts (Condon+ 1991)
Byte-by-byte Description of file: table1.dat
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Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 15 A15 --- Name Galaxy name
17- 22 F6.2 Mpc Dist Distance
24- 28 A5 --- Type Type of Active Galactic Nucleus (AGN)
30 A1 --- MType Morphological type (E=Elliptical-like,
S=Spiral-like, I=Irregular)
32- 37 F6.2 mag JMag ? 2MASS J band absolute magnitude
39- 42 F4.2 mag e_JMag ? Error in Jmag
44- 48 F5.2 [Msun/kpc2] Sigma Log of stellar mass surface density
estimated with 3.6µm flux
(log(ΣM3.6))
50- 53 F4.2 [Msun/kpc2] e_Sigma Error in Sigma
55- 59 F5.2 [Msun/yr/kpc2] SFR1 Log of star formation surface density
estimated with 8µm dust emission
(log(ΣSFR))
61- 64 F4.2 [Msun/yr/kpc2] e_SFR1 Error in SFR
66- 71 F6.2 [yr-1] SFR2 Specific star formation rate surface
density (log(ΣSSFR))
73- 76 F4.2 [yr-1] e_SFR2 Error in SFR2
78- 82 F5.2 [erg/s] Lum ? Log of 8GHz luminosity log(νL8GHz)
84- 87 F4.2 [erg/s] e_Lum ? Error in Lum
89- 91 A3 --- f_Lum [abc,] Source of Lum (a, b, or c) (1)
93- 96 F4.2 arcsec Beam ? Beam size of 8GHz observation
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Note (1): Flag defined as follows:
a = 8GHz luminosity is estimated from Thean et al. (2000MNRAS.314..573T 2000MNRAS.314..573T). Some
of these targets might contain non-nuclei contribution;
b = 8GHz luminosity is estimated from Morganti et al. (1999A&AS..137..457M 1999A&AS..137..457M).
Some of these targets might contain non-nuclei contribution;
c = We note that the diameter of NGC0185 is less than 2kpc.
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Byte-by-byte Description of file: table2.dat
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Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 9 A9 --- Name Galaxy name
11- 14 F4.1 Mpc Dist Distance
16- 21 F6.2 mag JMag ? 2MASS J-band absolute magnitude
23- 26 F4.2 mag e_JMag ? Error in JMag
28 A1 --- MType Morphological type (E=Elliptical-like,
S=Spiral-like, I=Irregular)
30- 33 F4.2 [Msun/kpc2] Sigma Log of stellar mass surface density
estimated with 3.6µm flux
(log(ΣM3.6))
35- 38 F4.2 [Msun/kpc2] e_Sigma Error in Sigma
40- 44 F5.2 [Msun/yr/kpc2] SFR1 Log of star formation surface density
estimated with 8µm dust emission
(log(ΣSFR))
46- 49 F4.2 [Msun/yr/kpc2] e_SFR1 Error in SFR1
51- 56 F6.2 [yr-1] SFR2 Log of specific star formation rate
surface density (log(ΣSSFR))
58- 61 F4.2 [yr-1] e_SFR2 Error in SFR2
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History:
From electronic version of the journal
(End) Sylvain Guehenneux [CDS] 24-Nov-2015