AGNs with composite spectra

Gonçalves, A. C.; Véron-Cetty, M. P.; Véron, Philippe

doi:10.1051/aas:1999183

Cited by 72 publications

(77 citation statements)

References 124 publications

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“…The type 1 AGN nature of the nucleus was already reported by Sanders et al (1988). 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).…”

Section: Ugc 05101 (Iras 09320+6134)supporting

confidence: 81%

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

González‐Martín¹,

Masegosa

Márquez

et al. 2009

A&A

173

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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Section: Ugc 05101 (Iras 09320+6134)supporting

confidence: 81%

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

González‐Martín¹,

Masegosa

Márquez

et al. 2009

A&A

173

226

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“…A result consistent with this scenario is the spettroscopic discovery in the nuclear region of 4C 26.42 of two clouds with a difference velocity of ∼330 km s −1 . Their emission line ratios of Hα and Hβ are very similar and typical of Liners exceptionally weak O [III] lines (Gonçalves et al 1999). However, no clear evidence of rotating gas has been found.…”

Section: Discussionmentioning

confidence: 68%

The parsec-scale properties of the radio galaxy 4C 26.42 in the dense cooling core cluster A1795

Liuzzo

Taylor

Giovannini

et al. 2009

A&A

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Aims. The aim of the present work is to study the radio emission on the parsec scale of 4C 26.42, the Brightest cluster galaxy in Abell 1795, in the framework of radiosources in a dense cool core cluster. Methods. We present Very Long Baseline Array (VLBA) observations at 1.6, 5, 8.4 and 22 GHz. We performed a spectral index and multiepoch analysis. Results. The source appears two-sided with a well defined and symmetric Z-structure at ∼5 mas from the core. The kiloparsec-scale morphology is similar to the parsec-scale structure, but reversed in PA, with symmetric 90 • bends at about 2 arcsec from the nuclear region. Comparing data obtained at 3 different epochs we derive a 3σ limit to the apparent proper motion of β a < 0.04. We suggest that the parsec-scale jets are sub-relativistic, in contrast with the high velocities found for most low-power radio galaxies. The origin of the unusual radio morphology remains a puzzle. We suggest that the identification of the parent galaxy with the central cD in a cooling cluster plays an important role in the properties and structure of the jets.

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“…For example, Mazzarella et al (1991); Riffel et al (2006) classified this source as a SB. Yet, according to Gonçalves et al (1999), its optical nuclear spectrum is not only starburst-dominated, but also hosts a Seyfert 2 (Sy 2) nuclei. In fact, many studies have classified this source as a Sy 2 (e.g.…”

Section: Sample and Previous Stellar Population Studiesmentioning

confidence: 99%

Probing the circumnuclear stellar populations of starburst galaxies in the near-infrared

Dametto

Riffel

Pastoriza

et al. 2014

Monthly Notices of the Royal Astronomical Society

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We employ the NASA Infrared Telescope Facility's near-infrared spectrograph SpeX at 0.8-2.4µm to investigate the spatial distribution of the stellar populations (SPs) in four well known Starburst galaxies: NGC 34, NGC 1614, NGC 3310 and NGC 7714. We use the STARLIGHT code updated with the synthetic simple stellar populations models computed by Maraston (2005, M05). Our main results are that the NIR light in the nuclear surroundings of the galaxies is dominated by young/intermediate age SPs (t 2 × 10 9 yr), summing from ∼40% up to 100% of the light contribution. In the nuclear aperture of two sources (NGC 1614 and NGC 3310) we detected a predominant old SP component (t > 2 × 10 9 yr), while for NGC 34 and NGC 7714 the younger component prevails. Furthermore, we found evidence of a circumnuclear star formation ring-like structure and a secondary nucleus in NGC 1614, in agreement with previous studies. We also suggest that the merger/interaction experienced by three of the galaxies studied, NGC 1614, NGC 3310 and NGC 7714 can explain the lower metallicity values derived for the young SP component of these sources. In this scenario the fresh unprocessed metal poorer gas from the destroyed/interacting companion galaxy is driven to the centre of the galaxies and mixed with the central region gas, before star formation takes place. In order to deepen our analysis, we performed the same procedure of SP synthesis using Maraston & Strömbäck (2011, M11) EPS models. Our results show that the newer and higher resolution M11 models tend to enhance the old/intermediate age SP contribution over the younger ages.

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AGNs with composite spectra

Cited by 72 publications

References 124 publications

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

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

The parsec-scale properties of the radio galaxy 4C 26.42 in the dense cooling core cluster A1795

Probing the circumnuclear stellar populations of starburst galaxies in the near-infrared

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