J/MNRAS/419/687 Morphology of luminous radio-loud AGN (Ramos Almeida+, 2012)
Are luminous radio-loud active galactic nuclei triggered by galaxy interactions?
Ramos Almeida C., Bessiere P.S., Tadhunter C.N., Perez-Gonzalez P.G.,
Barro G., Inskip K.J., Morganti R., Holt J., Dicken D.
<Mon. Not. R. Astron. Soc., 419, 687-705 (2012)>
=2012MNRAS.419..687R 2012MNRAS.419..687R (SIMBAD/NED BibCode)
ADC_Keywords: Active gal. nuclei ; Morphology
Keywords: galaxies: active - galaxies: elliptical and lenticular, cD -
galaxies: evolution - galaxies: interactions - galaxies: nuclei
Abstract:
We present the results of a comparison between the optical
morphologies of a complete sample of 46 southern 2Jy radio galaxies
at intermediate redshifts (0.05<z<0.7) and those of two control
samples of quiescent early-type galaxies: 55 ellipticals at redshifts
z≤0.01 from the Observations of Bright Ellipticals at Yale (OBEY)
survey, and 107 early-type galaxies at redshifts 0.2<z<0.7 in the
Extended Groth Strip (EGS). Based on these comparisons, we discuss the
role of galaxy interactions in the triggering of powerful radio
galaxies (PRGs). We find that a significant fraction of quiescent
ellipticals at low and intermediate redshifts show evidence for
disturbed morphologies at relatively high surface brightness levels,
which are likely the result of past or on-going galaxy interactions.
However, the morphological features detected in the galaxy hosts of
the PRGs (e.g. tidal tails, shells, bridges, etc.) are up to 2mag
brighter than those present in their quiescent counterparts. Indeed,
if we consider the same surface brightness limits, the fraction of
disturbed morphologies is considerably smaller in the quiescent
population (53% at z<0.2 and 48% at 0.2≤z<0.7) than in the PRGs (93%
at z<0.2 and 95% at 0.2≤z<0.7 considering strong-line radio galaxies
only). This supports a scenario in which PRGs represent a fleeting
active phase of a subset of the elliptical galaxies that have recently
undergone mergers/interactions. However, we demonstrate that only a
small proportion (≲20%) of disturbed early-type galaxies are capable
of hosting powerful radio sources.
Description:
We selected control samples of elliptical galaxies in two redshift
ranges which best match the 2 Jy sample host galaxies: the
Observations of Bright Ellipticals at Yale (OBEY, Tal et al.,
2009AJ....138.1417T 2009AJ....138.1417T) survey and the Extended Groth Strip (EGS) sample.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 80 55 Full classification of the OBEY survey ordered
by RA
table2.dat 63 107 Full classification of the EGS sample ordered by
Infrared Array Camera (IRAC) ID
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Byte-by-byte Description of file: table1.dat
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Bytes Format Units Label Explanations
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1- 9 A9 --- Name Galaxy name
11- 12 I2 h RAh Right ascension (J2000)
14- 15 I2 min RAm Right ascension (J2000)
17- 20 F4.1 s RAs Right ascension (J2000)
22 A1 --- DE- Declination sign (J2000)
23- 24 I2 deg DEd Declination (J2000)
26- 27 I2 arcmin DEm Declination (J2000)
29- 30 I2 arcsec DEs Declination (J2000)
32- 37 F6.4 --- z NED spectroscopic redshift
39- 44 F6.2 mag BMAG Absolute B magnitude (1)
46- 49 F4.2 mag B-V B-V colour index (Vega) (2)
51- 60 A10 "date" Obs.date Observation date
62- 66 F5.3 --- Tc Tidal parameter (3)
68- 76 A9 --- Morph Morphological classification (G1)
78- 80 A3 --- Group Group(s) (G2)
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Note (1): B-band absolute magnitudes from Tully (1988, NGC catalog,
Cat. VII/118) and corrected to H0=70km/s/Mpc
Note (2): Vega (B-V) colour within effective radius from Michard (2005, Cat.
J/A+A/441/451) and de Vaucouleurs et al. (1991, RC3, Cat. VII/155)
Note (3): tidal parameter reported in Tal et al. (2009AJ....138.1417T 2009AJ....138.1417T).
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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- 6 I6 --- IRAC IRAC ID (Rainbow data base identifier)
8- 9 I2 h RAh Right ascension (J2000)
11- 12 I2 min RAm Right ascension (J2000)
14- 17 F4.1 s RAs Right ascension (J2000)
19 A1 --- DE- Declination sign (J2000)
20- 21 I2 deg DEd Declination (J2000)
23- 24 I2 arcmin DEm Declination (J2000)
26- 27 I2 arcsec DEs Declination (J2000)
29- 32 F4.2 --- zphot Photometric redshift
34- 39 F6.2 mag BMAG Absolute B magnitude
41- 44 F4.2 mag Mu-Mg Rest-frame Mu-Mg colour from the
Rainbow data base
46- 47 A2 --- Type Indicates whether a galaxy has been visually
classified as an elliptical (E) or as a
possible disc (PD)
49- 59 A11 --- Morph Morphological classification (G1)
61- 63 A3 --- Group Group(s) (G2)
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Global notes:
Note (G1): Features with uncertain identification (within brackets) have not
been considered in the statistics discussed in this work. Code as follows:
A = amorphous halo
F = fan
T = tail
B = bridge
I = irregular feature
S = shell
D = dust feature
2N = double nucleus
3N = triple nucleus
Note (G2): Groups as follows:
1 = galaxy pair or group in tidal interaction
2 = galaxies showing T, F, S, D, A, I
3 = multiple nuclei (inside a 10.kpc)
4 = galaxies with dust as the only detected feature
5 = isolated galaxies with no sign of interaction
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History:
From electronic version of the journal
(End) Patricia Vannier [CDS] 14-Dec-2015