J/A+A/549/A58 3C 236 CO maps (Labiano+, 2013)
Fueling the central engine of radio galaxies.
II. The footprints of AGN feedback on the ISM of 3C 236.
Labiano A., Garcia-Burillo S., Combes F., Usero A., Soria-Ruiz R.,
Tremblay G., Neri R., Fuente A., Morganti R., Oosterloo T.
<Astron. Astrophys. 549, A58 (2013)>
=2013A&A...549A..58L 2013A&A...549A..58L
ADC_Keywords: Galaxies, radio ; Redshifts ; Carbon monoxide
Keywords: galaxies: individual: 3C 236 - galaxies: ISM -
galaxies: kinematics and dynamics - ISM: jets and outflows -
galaxies: active
Abstract:
There is growing observational evidence of active galactic nuclei
(AGN) feedback on the ISM of radio-quiet and radio-loud galaxies.
While AGN feedback is expected to be more common at high redshift
objects, the study of local universe galaxies help to better
characterize the different manifestations of AGN feedback.AIMS.
Molecular line observations can be used to quantify the mass and
energy budget of the gas affected by AGN feedback. We study the
emission of molecular gas in 3C 236, a Faranoff-Riley type 2 (FR II)
radio source at z∼0.1, and search for the footprints of AGN
feedback. 3C 236 shows signs of a reactivation of its AGN triggered by
a recent minor merger episode. Observations have also previously
identified an extreme HI outflow in this source.
The IRAM Plateau de Bure interferometer (PdBI) has been used to study
the distribution and kinematics of molecular gas in 3C 236 by imaging
with high spatial resolution (0.6") the emission of the 2-1 line of
12CO in the nucleus of the galaxy. We have searched for outflow
signatures in the CO map. We have also derived the star-formation rate
(SFR) in 3C 236 using data available from the literature at UV,
optical and IR wavelengths, to determine the star-formation efficiency
of molecular gas.
The CO emission in 3C 236 comes from a spatially resolved ∼1.4"
(2.6kpc)-diameter disk characterized by a regular rotating pattern.
Within the limits imposed by the sensitivity and velocity coverage of
the CO data, we do not detect any outflow signatures in the cold
molecular gas. The disk has a cold gas mass M(H2)∼2.1x109M☉.
Based on CO we determine a new value for the redshift of the source
zCO=0.09927±0.0002. The similarity between the CO and HI profiles
indicates that the deep HI absorption in 3C 236 can be accounted for
by a rotating HI structure. This restricts the evidence of HI
outflow only to the most extreme velocities. In the light of the new
redshift value, the analysis of the ionized gas kinematics reveals a
fast (∼1000km/s) outflow. As for the CO emitting gas, outflow
signatures are nevertheless absent in the warm molecular gas emission
traced by infrared H2 lines. The star-formation efficiency in 3C 236
is consistent with the value measured in normal galaxies, which follow
the canonical Kennicutt-Schmidt (KS) relation. This result, confirmed
to hold in other young radio sources examined in this work, is in
stark contrast with the factor of 10-50 lower SFE that has been
claimed to characterize evolved powerful radio galaxies.
There are no signs of ongoing AGN feedback on the molecular ISM of 3C
236. The recent reactivation of the AGN in 3C 236 (about ∼105yr ago)
is a likely explanation for the early evolutionary status of its
molecular disk.
Description:
Continuum maps at 1 mm and 3mm. Map of the integrated 12CO(2-1)
line.
Objects:
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RA (2000) DE Designation(s)
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10 06 01.73 +34 54 10.4 3C 236 = 2MASX J10060176+3454104
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File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
list.dat 70 3 List of FITS maps
maps/* . 3 FITS maps
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Byte-by-byte Description of file: list.dat
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Bytes Format Units Label Explanations
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1- 9 F9.5 deg RAdeg Right Ascension of center (J2000)
10- 18 F9.5 deg DEdeg Declination of center (J2000)
20- 25 F6.4 arcsec/pix Scale Scale of the image
27- 29 I3 pix Nx Number of pixels along X-axis
30 A1 --- --- [x]
31- 33 I3 pix Ny Number of pixels along Y-axis
34 A1 --- --- [x]
35- 36 I2 --- Nz ? Number of slices (in velocity)
38- 41 I4 km/s V0 ? Velocity (lower limit) (LSR)
43- 46 I4 km/s V1 ? Velocity (upper limit) (LSR)
48- 56 A9 --- FileName Name of FITS file, in subdirectory maps
58- 80 A23 --- Text Explanations
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Acknowledgements:
Alvaro Labiano, a.labiano(at)oan.es
References:
Garcia-Burillo et al., Paper I 2007A&A...468L..71G 2007A&A...468L..71G
(End) Alvaro Labiano [CAB, Spain], Patricia Vannier [CDS] 23-Nov-2012