J/AJ/155/188 Origin of nuclear activity in low-power radio galaxies (Lin+, 2018)
An analysis framework for understanding the origin of nuclear activity
in low-power radio galaxies.
Lin Y.-T., Huang H.-J., Chen Y.-C.
<Astron. J., 155, 188 (2018)>
=2018AJ....155..188L 2018AJ....155..188L (SIMBAD/NED BibCode)
ADC_Keywords: Galaxies, radio ; Clusters, galaxy ; Active gal. nuclei ;
Redshifts ; Photometry, SDSS ; Stars, masses ;
Effective temperatures
Keywords: galaxies: active - galaxies: clusters: general -
galaxies: elliptical and lenticular, cD - radio continuum: galaxies
Abstract:
Using large samples containing nearly 2300 active galaxies of low radio
luminosity (1.4 GHz luminosity between 2x1023 and 3x1025 W/Hz,
essentially low-excitation radio galaxies) at z~<0.3, we present
a self-contained analysis of the dependence of the nuclear radio activity
on both intrinsic and extrinsic properties of galaxies, with the goal
of identifying the best predictors of the nuclear radio activity.
While confirming the established result that stellar mass must play a
key role on the triggering of radio activities, we point out that for
the central, most massive galaxies, the radio activity also shows a
strong dependence on halo mass, which is not likely due to enhanced
interaction rates in denser regions in massive, cluster-scale halos.
We thus further investigate the effects of various properties of the
intracluster medium (ICM) in massive clusters on the radio activities,
employing two standard statistical tools, principle component analysis
and logistic regression. It is found that ICM entropy, local cooling
time, and pressure are the most effective in predicting the radio
activity, pointing to the accretion of gas cooling out of a hot
atmosphere to be the likely origin in triggering such activities in
galaxies residing in massive dark matter halos. Our analysis framework
enables us to logically discern the mechanisms responsible for the
radio activity separately for central and satellite galaxies.
Description:
The radio galaxy (RG) sample used in this section is based on two large
RG catalogs: one is that of Lin et al. (2010, J/ApJ/723/1119), which
covers the footprint of SDSS DR6 (Cat. III/255) and is available in Table 7,
the other is taken from Best & Heckman (2012, J/MNRAS/421/1569), covering
DR7 (Cat. II/294). Both studies cross match SDSS galaxy samples with
1.4 GHz radio source catalogs from NVSS and FIRST, largely following
the methodology outlined in Best et al. (2005, J/MNRAS/362/9). To ensure
the radio sources are powered (primarily) by an active nucleus, a
combination of diagnostics is used to select RGs, including the BPT diagram
(Baldwin et al. 1981PASP...93....5B 1981PASP...93....5B), the distributions of objects in the
4000 Å versus radio power, and Hα versus radio power planes (see
modifications discussed in Best & Heckman 2012, J/MNRAS/421/1569).
To investigate the effect of the ICM on triggering of the radio activity,
we make use of the X-ray measurements in the Archive of Chandra Cluster
Entropy Profile Tables (ACCEPT) database (Cavagnolo et al. 2009,
J/ApJS/182/12), which is an attempt to homogeneously analyze Chandra
observations of about 230 galaxy clusters. We can thus use the SDSS
(imaging and spectroscopic) data to identify cluster members and study
the correlations between the radio activity and the local ICM properties.
We have run our RG finding algorithm on the ACCEPT-SDSS clusters, with
a flux limit of 1 mJy that is suitable for FIRST and have visually
inspected all potential optical-radio matches to finalize our cluster RG
sample (see Table 8).
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
clusters.dat 42 56 List of host clusters
table7.dat 69 12898 Radio galaxy sample used in Section 2
table8.dat 92 563 Radio galaxy sample used in Section 3
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See also:
VIII/43 : Radio survey of clusters of galaxies (Andernach+ 1978)
VIII/65 : 1.4GHz NRAO VLA Sky Survey (NVSS) (Condon+ 1998)
III/255 : Spectroscopy of SDSS Data Release (SDSS-DR6) (ARC, 2007)
II/294 : The SDSS Photometric Catalog, Release 7 (Adelman-McCarthy+, 2009)
VIII/92 : The FIRST Survey Catalog, Version 2014Dec17 (Helfand+ 2015)
J/MNRAS/362/9 : Radio-loud AGN in SDSS (Best+, 2005)
J/MNRAS/379/867 : BCG C4 cluster catalog (von der Linden+, 2007)
J/MNRAS/381/211 : Radio galaxies in the 2SLAQ LRG Survey (Sadler+, 2007)
J/MNRAS/381/1369 : Redshifts in Subaru/XMM Deep Field (Geach+, 2007)
J/ApJS/182/12 : ICM entropy profiles (ACCEPT) (Cavagnolo+, 2009)
J/ApJ/723/1119 : Optical properties of radio galaxies at z<0.3 (Lin+, 2010)
J/MNRAS/421/1569 : Properties of 18286 SDSS radio galaxies (Best+, 2012)
Byte-by-byte Description of file: clusters.dat
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Bytes Format Units Label Explanations
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1- 16 A16 --- Cluster Host cluster identifier (as listed in Table 8)
18- 19 I2 h RAh Simbad Hour of Right Ascension (J2000)
21- 22 I2 min RAm Simbad Minute of Right Ascension (J2000)
24- 28 F5.2 s RAs Simbad Second of Right Ascension (J2000)
30 A1 --- DE- Simbad Sign of the Declination (J2000)
31- 32 I2 deg DEd Simbad Degree of Declination (J2000)
34- 37 F4.1 arcmin DEm Simbad Arcminute of Declination (J2000)
39- 42 F4.1 arcsec DEs ? Simbad Arcsecond of Declination (J2000)
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Byte-by-byte Description of file: table7.dat
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Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 10 F10.6 deg RAdeg Right Ascension in decimal degrees (J2000)
12- 21 F10.6 deg DEdeg Declination in decimal degrees (J2000)
23- 29 F7.5 --- z [0.01047/0.34993] Spectroscopic redshift
31- 36 F6.1 mJy F1.4 [0.9/7980] The 1.4 GHz flux density
38- 42 F5.2 [W/Hz] log(P1.4) [21.3/26.44] Log 1.4 GHz luminosity (1)
44- 52 F9.3 mag rMag [-25.548/26504.1] Restframe r0.1 band
AB magnitude (2)
54- 59 F6.2 [Msun] logM* [0/11.93]? Log stellar mass
(in M☉/h2) (G1)
60- 61 A2 --- n_logM* [-I ] -I for -∞
63 I1 --- AGN [0/1] Source powered by an AGN? (1=Yes, 0=No)
65 I1 --- Sel [0/1] Selection flag (1=Yes, 0=No) (3)
67- 69 A3 --- Ref Origin of the source (4)
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Note (1): Assuming a spectral index of -0.8.
Note (2): The r0.1 band means the SDSS r-band shifted blueward by a factor of
1.1 in wavelength; rmag-5log(h).
Note (3): Choosing sources with the selection flag with a value of 1 allows one
to obtain the z=<0.15 RG sample used in Section 2 (further restricting the
redshift to z=<0.092 gives the z=<0.092 subsample).
Note (4): Reference as follows:
L10 = Lin et al. (2010, J/ApJ/723/1119);
B12 = Best & Heckman (2012, J/MNRAS/421/1569).
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Byte-by-byte Description of file: table8.dat
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Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 10 F10.6 deg RAdeg Right Ascension in decimal degrees (J2000)
12- 20 F9.6 deg DEdeg Declination in decimal degrees (J2000)
22- 27 F6.4 --- z [0.027/0.3121] Spectroscopic redshift
29- 34 F6.1 kpc Dist [0/1358] Clustercentric distance
36- 40 F5.2 [Msun] logM* [10.28/11.99] Log stellar mass
(in M☉/h2) (G1)
42 I1 --- BCG [0/1] The galaxy is the Brightest Cluster
Galaxy (BCG)? (1=Yes, 0=No)
44- 48 F5.2 [W/Hz] log(P1.4) [23.5/27.25]? Log 1.4 GHz luminosity (1)
50- 53 F4.1 keV Temp [2/12.8] Mean cluster temperature
55- 58 F4.2 [keV.cm2] logK [1.07/3.49] Log local entropy
60- 65 F6.2 [10-5N/cm2] logP [-12.9/-8.86] Log local pressure
(in dyne/cm2)
67- 70 F4.1 [Gyr] logTc [-0.6/2.8] Log local cooling time
72- 75 F4.2 --- Tc/Tff [1.17/3.04] Ratio of local cooling to
free-fall times
77- 92 A16 --- Cluster Host cluster identifier
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Note (1): No value indicates luminosity below our threshold of Pth=23.5.
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Global notes:
Note (G1): Throughout this paper we adopt a WMAP5 (Komatsu et al.
2009ApJS..180..330K 2009ApJS..180..330K) ΛCDM cosmological model, where H0=100h km/s/Mpc
with h=0.71.
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History:
From electronic version of the journal
(End) Prepared by [AAS], Tiphaine Pouvreau [CDS] 23-Nov-2018