Radio properties of FIR-megamaser nuclei

Baan, Willem A.; Klöckner, H.-R.

doi:10.1051/0004-6361:20042331

Cited by 68 publications

(107 citation statements)

References 39 publications

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“…Our data agree with previous observations with the VLA by Baan & Klöckner (2006). These authors detected the same total flux density in a similar beam, but did not discuss the structure of the emission, assuming the source to be unresolved.…”

Section: 4 Ghz and 5 Ghz Continuumsupporting

confidence: 91%

High-resolution mm and cm study of the obscured LIRG NGC 4418

Costagliola

Aalto

Sakamoto

et al. 2013

A&A

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119

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Context. Understanding the nature of the power-source in luminous infrared galaxies (LIRG) is difficult due to their extreme obscuration. Observations at radio and mm wavelengths can penetrate large columns of dust and gas and provide unique insights into the properties of the compact obscured nuclei of LIRGs. Aims. The aim of this study is to constrain the dynamics, structure, and feeding of the compact nucleus of NGC 4418, and to reveal the nature of the main hidden power-source: starburst or active galactic nucleus (AGN). Methods. We obtained high spatial resolution observations of NGC 4418 at 1.4 and 5 GHz with MERLIN, and at 230 and 270 GHz with the SMA in very extended configuration. We used the continuum morphology and flux density to estimate the size of the emitting region, the star formation rate, and the dust temperature. Emission lines were used to study kinematics through position-velocity diagrams. Molecular emission was studied with population diagrams and by fitting a local thermal equilibrium (LTE) synthetic spectrum. Results. We detect bright 1-mm-line emission from CO, HC 3 N, HNC, and C 34 S and 1.4 GHz absorption from HI. The CO 2-1 emission and HI absorption can be fit by two velocity components at 2090 and 2180 km s −1 . We detect vibrationally excited HC 3 N and HNC, with T vib ∼ 300 K. Molecular excitation is consistent with a layered temperature structure, with three main components at 80, 160, and 300 K. For the hot component we estimate a source size of less than 5 pc. The nuclear molecular gas surface density of 10 4 M pc −2 is extremely high and similar to that found in the ultra-luminous infrared galaxy (ULIRG) Arp220. Conclusions. Our observations confirm the presence of a molecular and atomic in-flow, previously suggested by Herschel observations, which is feeding the activity in the center of NGC 4418. Molecular excitation confirms the presence of a very compact, hot dusty core. If a starburst is responsible for the observed IR flux, this has to be at least as extreme as the one in the ULIRG Arp 220, with an age of 3-10 Myr and a star formation rate >10 M yr −1 . If an AGN is present, it must be extremely Compton-thick.

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Section: 4 Ghz and 5 Ghz Continuumsupporting

confidence: 91%

High-resolution mm and cm study of the obscured LIRG NGC 4418

Costagliola

Aalto

Sakamoto

et al. 2013

A&A

Self Cite

119

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“…Farrah et al (2003) found that this system is a composite object containing both starburst and AGN contributions, consistent with the result for its optical spectrum (Goncalves et al 1999). New evidence come from radiofrequencies where it is found a compact nucleus with flat spectral shape (Baan & Klockner 2006). The Fe-K emission is marginally detected in the analysis of Chandra data by Ptak et al (2003).…”

Section: Ugc 05101 (Iras 09320+6134)supporting

confidence: 73%

“…F.11). A compact flat spectrum radio source has been detected between 2 and 6 cm (Baan & Klockner 2006). At high X-ray energies only the northern nucleus is detected (Fig.…”

Section: Ugc 08696 (Mrk 273 Iras 13428+5608)mentioning

confidence: 93%

“…Hattori et al (2004) indicate that the morphological appearance in radio continuum emission suggests that star-forming activity dominates the energetics of the northern galaxy (Pihlstrim et al 2001); the classification as a LINER may be due to a contribution from shock heating, possibly driven by superwind activity (Taniguchi et al 1999;Lutz et al 1999). However Baan & Klockner (2006) by means of observations at 1.4 and 8.4 GHz suggest an AGN nature of the radio continuum emission based in the compactness and flat index spectral nature of the nuclear source (see Table 12). …”

Section: Ngc 410 (Ugc 735)mentioning

confidence: 99%

“…F.13) containing several compact star clusters, with a single tail. Baan & Klockner (2006) detected a compact flat spectrum nuclear radio source. Its X-ray nuclear emission appears to be unresolved at high energies (Fig.…”

Section: Ngc 6251 (Ugc 10501)mentioning

confidence: 99%

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An X-ray view of 82 LINERs with Chandra and XMM-Newton data

González‐Martín¹,

Masegosa

Márquez

et al. 2009

A&A

179

226

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We present the results of a homogeneous X-ray analysis for 82 nearby low-ionisation, narrow emission-line regions (LINERs) selected from the catalogue of Carrillo et al. (1999, Rev. Mex. Astron. Astrofis., 35, 187). All sources have available Chandra (68 sources) and/or XMM-Newton (55 sources) observations. This is the largest sample of LINERs with X-ray spectral data (60 out of the 82 objects), and it significantly improves our previous analysis based on Chandra data for 51 LINERs (Gonzalez-Martin et al. 2006b, A&A, 460, 45). It both increases the sample size and adds XMM-Newton data. New models permit the inclusion of double absorbers in the spectral fits. Nuclear X-ray morphology is inferred from the compactness of detected nuclear sources in the hard band (4.5-8.0 keV). Sixty per cent of the sample shows a compact nuclear source and are classified as active galactic nucleus (AGN) candidates. The spectral analysis indicates that best fits involve a composite model: 1) absorbed primary continuum and 2) soft spectrum below 2 keV described by an absorbed scatterer and/or a thermal component. The resulting median spectral parameters and their standard deviations are Γ = 2.11 ± 0.52, kT = 0.54 ± 0.30 keV, log(NH1) = 21.32 ± 0.71 and log(NH2) = 21.93 ± 1.36. We complement our X-ray results with an analysis of HST optical images and literature data on emission lines, radio compactness, and stellar population. After adding all these multiwavelength data, we conclude that evidence supports the AGN nature of their nuclear engine for 80% of the sample (66 out of 82 objects).

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Far infrared properties of OH megamaser host galaxies

Wang

Lin

et al. 2023

J Astrophys Astron

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Radio properties of FIR-megamaser nuclei

Cited by 68 publications

References 39 publications

High-resolution mm and cm study of the obscured LIRG NGC 4418

High-resolution mm and cm study of the obscured LIRG NGC 4418

An X-ray view of 82 LINERs with Chandra and XMM-Newton data

Far infrared properties of OH megamaser host galaxies

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