Further clues to the nature of composite LINER/H II galaxies

Filho, M.; Fraternali, Filippo; Markoff, Sera; Nagar, N. M.; Barthel, Pieter; Ho, L. C.; Yuan, Feng

doi:10.1051/0004-6361:20034486

Cited by 82 publications

(139 citation statements)

References 48 publications

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“…A nuclear source is detected in the (4.5-8.0 * keV) band image from Chandra data. This agrees with the analysis by Filho et al (2004) who already noticed a hard nuclear X-ray source coincident with the optical nucleus. The luminosity they calculated with a fixed Γ = 1.7 is in excellent agreement with our estimation.…”

Section: Ngc 3245 (Ugc 5663)supporting

confidence: 93%

“…Their main conclusion based on the variability, the spectral analysis, and multi-wavelength data is that the central source is more likely a low-luminosity AGN than contribution from LMXBs (Low Mass X-ray Binaries). GM+06 best-fit parameters are consistent with a model of a power law (Γ = 1.81) plus a thermal RS (kT = 0.83 keV), in much better agreement with the results by Filho et al (2004) on the analysis of Chandra archival data, with Γ = 1.51 and kT = 0.95. The new Chandra spectral analysis is consistent with those obtained before.…”

Section: Ngc 4552 (Ugc 7760 M 89)supporting

confidence: 82%

“…F.5). Soft X-ray emission extends over about 2' in a NorthwestSoutheast direction, similar to the extent and orientation of the triple-radio source (Filho et al 2004). No obvious nuclear Xray source -hard or soft -was found on the available snapshot Chandra image (see (2006) noted that another source at 10" is present in this image with similar flux than that of the nucleus, which probably contaminates other data with worse spatial resolution (see also Georgantopoulos et al 2002).…”

Section: Ngc 3627 (Ugc 6346 Arp 16 M 66 Arp 317b)supporting

confidence: 55%

“…Table 12 lists the multiwavelength data discussed in this paper. Under the assumptions of the unified model, the main ingredients expected to be common to AGN are 1) a region of high velocity and high velocity dispersion, called the broad line region (BLR); 2) variability at UV; and 3) an unresolved radio compact core associated with a flat continuum (Filho et al 2004;Nagar et al 2005). The signature of any of these ingredients will be taken as an AGN signature.…”

Section: Multiwavelength Analysismentioning

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

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: Ngc 3245 (Ugc 5663)supporting

confidence: 93%

Section: Ngc 4552 (Ugc 7760 M 89)supporting

confidence: 82%

Section: Ngc 3627 (Ugc 6346 Arp 16 M 66 Arp 317b)supporting

confidence: 55%

Section: Multiwavelength Analysismentioning

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

173

226

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“…X-ray and radio studies are available in the literature for a few galaxies in our sample. Compact nuclear X-ray and/or radio sources have been detected in IC 5063 (Koyama et al 1992 ( Balmaverde et al 2006), NGC 5090 (Grützbauch et al 2007), IC 4296 (Pellegrini et al 2003), NGC 5077, (Filho et al 2006), and NGC 4552 (Nagar et al 2002;Filho et al 2004). …”

Section: Comparison With Modelsmentioning

confidence: 99%

Nearby early-type galaxies with ionized gas

Annibali

Bressan

Rampazzo

et al. 2010

A&A

121

162

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Aims. A significant fraction of early-type galaxies (ETGs) exhibit emission lines in their optical spectra. We attempt to identify the producing the emission mechanism and the ionized gas in ETGs, and its connection with the host galaxy evolution. Methods. We analyzed intermediate-resolution optical spectra of 65 ETGs, mostly located in low density environments and exhibiting spectros-copic diagnostic lines of ISM from which we had previously derived stellar population properties. To extract the emission lines from the galaxy spectra, we developed a new fitting procedure that accurately subtracts the underlying stellar continuum, and accounts for the uncertainties caused by the age-metallicity degeneracy. Results. Optical emission lines are detected in 89% of the sample. The incidence and strength of emission correlate with neither the E/S0 classification, nor the fast/slow rotator classification. By means of the classical [OIII]/Hβ versus [NII]/Hα diagnostic diagram, the nuclear galaxy activity is classified such that 72% of the galaxies with emission are LINERs, 9% are Seyferts, 12% are composite/transition objects, and 7% are non-classified. Seyferts have young luminostiy-weighted ages ( 5 Gyr), and appear, on average, significantly younger than LINERs and composites. Excluding the Seyferts from our sample, we find that the spread in the ([OIII], Hα, or [NII]) emission strength increases with the galaxy central velocity dispersion σ c . Furthermore, the [NII]/Hα ratio tends to increase with σ c . The [NII]/Hα ratio decreases with increasing galactocentric distance, indicative of either a decrease in the nebular metallicity, or a progressive "softening" of the ionizing spectrum. The average nebular oxygen abundance is slightly less than solar, and a comparison with the results obtained in Paper III from Lick indices shows that it is ≈0.2 dex lower than that of stars. Conclusions. The nuclear (r < r e /16) emission can be attributed to photoionization by PAGB stars alone only for ≈22% of the LINER/composite sample. On the other hand, we cannot exclude an important role of PAGB star photoionization at larger radii. For the major fraction of the sample, the nuclear emission is consistent with excitation caused by either a low-accretion rate AGN or fast shocks (200-500 km s −1 ) in a relatively gas poor environment (n 100 cm −3 ), or both. The derived [SII]6717/6731 ratios are consistent with the low gas densities required by the shock models. The derived nebular metallicities are indicative of either an external origin of the gas, or an overestimate of the oxygen yields by SN models.

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The Globular Cluster System of NGC 5846 Revisited: Colours, Sizes and X-Ray Counterparts

Chies-Santos

Santiago

Pastoriza

et al. 2009

Globular Clusters - Guides to Galaxies

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Abstract. NGC 5846 is a giant elliptical galaxy with a previously well studied globular cluster system (GCS), known to have a bimodal colour distribution with a remarkably high red fraction. Here we revisit the central galaxy regions searching for new globular cluster (GC) candidates, and measure magnitudes, colours and sizes for them. We also search for their X-ray counterparts. We use archival Hubble Space Telescope WFPC2 images, from which we modelled and subtracted the host light distribution to increase the available sample of GCs. We performed photometry on the central objects, and measured sizes and coordinates for the entire GC system known in this galaxy. We detect two dozen previously unknown GC candidates in the central regions. Reliable sizes are obtained for about 60 GCs; their typical effective radii are in the range 3 − 5 pc. The largest clusters are located in the central regions. We find 7 X-ray counterparts to GCs, most of them in the central region. They are among the most luminous X-ray sources in NGC 5846. They are also optically luminous, compact and belong to the red subpopulation. The GCS of NGC 5846 is composed of relatively luminous X-ray sources.

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Further clues to the nature of composite LINER/H II galaxies

Cited by 82 publications

References 48 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

Nearby early-type galaxies with ionized gas

The Globular Cluster System of NGC 5846 Revisited: Colours, Sizes and X-Ray Counterparts

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