A. Labiano

GPS radio sources: new optical observations and an updated master list

Aims. We identify optical counterparts, address uncertain identifications and measure previously unknown redshifts of the host galaxies of candidate GPS radio sources, and study their stellar populations. Methods. Long slit spectroscopy and deep optical imaging in the B, V and R bands, obtained with the Very Large Telescope. Results. We obtain new redshifts for B0316+161, B0407-658, B0904+039, B1433-040, and identify the optical counterparts of B0008-421 and B0742+103. We confirm the previous identification for B0316+161, B0407-658, B0554-026, and B0904+039, and find that the previous identification for B0914+114 is incorrect. Using updated published radio spectral information, we classify as non GPS the following sources: B0407-658, B0437-454, B1648+015. The optical colors of typical GPS sources are consistent with single instantaneous burst stellar population models but do not yield useful information on age or metallicity. A new master list of GPS sources is presented.

Star formation in the hosts of GHz peaked spectrum and compact steep spectrum radio galaxies

Aims. We are searching for star formation regions in the hosts of potentially young radio galaxies (gigahertz peaked spectrum and compact steep spectrum sources). Methods. We used near-UV imaging with the Hubble Space Telescope Advanced Camera for Surveys. Results. We find near-UV light could be the product of recent star formation in five of the nine observed sources, though other explanations are not currently ruled out. An additional two sources show marginal detections. The UV luminosities of the GPS and CSS sources are similar to those of a sample of nearby large-scale radio galaxies. Stellar-population synthesis models are consistent with a burst of recent star formation occurring before the formation of the radio source. However, observations at other wavelengths and colors are needed to definitively establish the nature of the observed UV light. In the CSS source 1443+77, the near-UV light is aligned with and is co-spatial with the radio source. We suggest that the UV light in this source is produced by star formation triggered and/or enhanced by the radio source.

PMAS optical integral field spectroscopy of luminous infrared galaxies - I. The atlas

In this paper we present PMAS optical (3800-7200A) IFS of the northern hemisphere portion of a volume-limited sample of 11 LIRGs. The PMAS observations typically cover the central ~5kpc and are complemented with HST/NICMOS images. For most LIRGs in our sample, the peaks of the continuum and gas (e.g., Halpha, [NII]) emissions coincide, unlike what is observed in local, strongly interacting ULIRGs. The only exceptions are galaxies with circumnuclear rings of star formation where the most luminous Halpha emitting regions are found in the rings rather than in the nuclei, and the displacements are well understood in terms of differences in the stellar populations. A large fraction of the nuclei of these LIRGs are classified as LINER and intermediate LINER/HII, or composite objects. The excitation conditions of the integrated emission depend on the relative contributions of HII regions and the diffuse emission to the line emission over the PMAS FoV. Galaxies dominated by high surface-brightness HII regions show integrated HII-like excitation. A few galaxies show slightly larger integrated [NII]/Halpha and [SII]/Halpha line ratios than the nuclear ones, probably because of more contribution from the diffuse emission. The Halpha velocity fields over the central few kpc are generally consistent, at least to first order, with rotational motions. The velocity fields of most LIRGs are similar to those of disk galaxies, in contrast to the highly perturbed fields of most local, strongly interacting ULIRGs. The peak of the Halpha velocity dispersion coincides with the position of the nucleus and is likely to be tracing mass. All these results are similar to the properties of z~1 LIRGs, and they highlight the importance of detailed studies of flux-limited samples of local LIRGs. (Abridged)

Fueling the central engine of radio galaxies - III. Molecular gas and star formation efficiency of 3C 293

Context. Powerful radio galaxies show evidence of ongoing active galactic nuclei (AGN) feedback, mainly in the form of fast, massive outflows. But it is not clear how these outflows affect the star formation of their hosts. Aims. We investigate the different manifestations of AGN feedback in the evolved, powerful radio source 3C 293 and their impact on the molecular gas of its host galaxy, which harbors young star-forming regions and fast outflows of H i and ionized gas. Methods. We study the distribution and kinematics of the molecular gas of 3C 293 using high spatial resolution observations of the 12 CO(1−0) and 12 CO(2−1) lines, and the 3 mm and 1 continuum taken with the IRAM Plateau de Bure interferometer. We mapped the molecular gas of 3C 293 and compared it with the dust and star-formation images of the host. We searched for signatures of outflow motions in the CO kinematics, and re-examined the evidence of outflowing gas in the H i spectra. We also derived the star formation rate (SFR) and star formation efficiency (SFE) of the host with all available SFR tracers from the literature, and compared them with the SFE of young and evolved radio galaxies and normal star-forming galaxies. Results. The 12 CO(1−0) emission line shows that the molecular gas in 3C 293 is distributed along a massive (M(H2) ∼ 2.2 × 10 10 M� ) ∼24 �� (21 kpc-) diameter warped disk, that rotates around the AGN. Our data show that the dust and the star formation are clearly associated with the CO disk. The 12 CO(2−1) emission is located in the inner 7 kpc (diameter) region around the AGN, coincident with the inner part of the 12 CO(1−0) disk. Both the 12 CO(1−0) and 12 CO(2−1) spectra reveal the presence of an absorber against the central regions of 3C 293 that is associated with the disk. We do not detect any fast (500 km s −1 ) outflow motions in the cold molecular gas. The host of 3C 293 shows an SFE consistent with the Kennicutt-Schmidt law of normal galaxies and young radio galaxies, and it is 10–50 times higher than the SFE estimated with the 7.7 μm PAH emission of evolved radio galaxies. Our results suggest that the apparently low SFE of evolved radio galaxies may be caused by an underestimation of the SFR and/or an overestimation of the molecular gas densities in these sources. Conclusions. The molecular gas of 3C 293, while not incompatible with a mild AGN-triggered flow, does not reach the high velocities (500 km s −1 ) observed in the H i spectrum. We find no signatures of AGN feedback in the molecular gas of 3C 293.

Fueling the central engine of radio galaxies - II. The footprints of AGN feedback on the ISM of 3C 236

Context. There is growing observational evidence of active galactic nuclei (AGN) feedback on the interstellar medium (ISM) of radio-quiet and radio-loud galaxies. While AGN feedback is expected to be more common at high-redshift objects, studying local universe galaxies helps 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. The source 3C 236 shows signs of a reactivation of its AGN triggered by a recent minor merger episode. Observations have also previously identified an extreme H i outflow in this source. Methods: The IRAM Plateau de Bure interferometer (PdBI) was 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 searched for outflow signatures in the CO map. We 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 (SFE) of molecular gas. Results: The CO emission in 3C 236 comes from a spatially resolved ~1.4″(2.6 kpc-) 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) ~ 2.1 × 109 M⊙. 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 H i profiles indicates that the deep H i absorption in 3C 236 can be accounted for by a rotating H i structure. This restricts the evidence of H i outflow to only the most extreme velocities. In the light of the new redshift value, the analysis of the ionized gas kinematics reveals a fast (~1000 km s-1) outflow. Outflow signatures in the CO emitting gas, are nevertheless absent in the warm molecular gas emission traced by infrared H2 lines. The SFE 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 SFE that is lower by a factor 10-50 that has been claimed to characterize evolved powerful radio galaxies. Conclusions: There are no signs of ongoing AGN feedback to the molecular ISM of 3C 236. The recent reactivation of the AGN in 3C 236 (about 105 yr ago) is a likely explanation for the early evolutionary status of its molecular disk. Based on observations carried out with the IRAM Plateau de Bure Interferometer. IRAM is supported by INSU/CNRS (France), MPG (Germany) and IGN (Spain).The datacube (in FITS format) is only available at the CDS via anonymous ftp to cdsarc.u-strasbg.fr (130.79.128.5) or via http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/549/A58

First results from MIRI verification model testing

The Mid-Infrared Instrument (MIRI) is one of the three scientific instruments to fly on the James Webb Space Telescope (JWST), which is due for launch in 2013. MIRI contains two sub-instruments, an imager, which has low resolution spectroscopy and coronagraphic capabilities in addition to imaging, and a medium resolution IFU spectrometer. A verification model of MIRI was assembled in 2007 and a cold test campaign was conducted between November 2007 and February 2008. This model was the first scientifically representative model, allowing a first assessment to be made of the performance. This paper describes the test facility and testing done. It also reports on the first results from this test campaign.

Outflows of hot molecular gas in ultra-luminous infrared galaxies mapped with VLT-SINFONI

We present the detection and morphological characterization of hot molecular gas outflows in nearby ultra-luminous infrared galaxies, using the near-IR integral-field spectrograph SINFONI on the VLT. We detect outflows observed in the 2.12 micron H

Resolving the Nuclear Obscuring Disk in the Compton-thick Seyfert Galaxy NGC 5643 with ALMA

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Spatially resolved cold molecular outflows in ULIRGs

1-0 S(1) line for three out of four ULIRGs analyzed; IRAS 12112+0305, 14348-1447, and 22491-1808. The outflows are mapped on scales of 0.7-1.6 kpc, show typical outflow velocities of 300-500 km/s, and appear to originate from the nuclear region. The outflows comprise hot molecular gas masses of ~6-8x10

Optimizing parallel observations for the JWST/MIRI instrument

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