The presence and distribution of H I absorbing gas in sub-galactic sized radio sources

Pihlstroem, Y. M.; Conway, J. E.; Vermeulen, R. C.

doi:10.1051/0004-6361:20030469

Cited by 108 publications

(222 citation statements)

References 57 publications

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“…This could be the signature of physically different absorption systems (Vink et al 2005;Guainazzi et al 2006) or of a single system characterised by a spin temperature ∼ > 10 3 K (Ostorero et al 2009). We report a possible anti-correlation between the projected linear size of the radio source and the X-ray column density, analogous to the anti-correlation between radio size and HI column density reported by Pihlström et al (2003) and . -GPS galaxies occupy a specific locus in the radio versus X-ray luminosity plane.…”

Section: Discussionsupporting

confidence: 83%

The X-ray view of giga-hertz peaked spectrum radio galaxies

Tengstrand

Guainazzi

Siemiginowska

et al. 2009

A&A

100

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Context. This paper presents the X-ray properties of a flux-and volume-limited complete sample of 16 giga-hertz peaked spectrum (GPS) galaxies. Aims. This study addresses three basic questions in our understanding of the nature and evolution of GPS sources: a) What is the physical origin of the X-ray emission in GPS galaxies? b) Which physical system is associated with the X-ray obscuration? c) What is the "endpoint" of the evolution of compact radio sources? Methods. We discuss in this paper the results of the X-ray spectral analysis, and compare the X-ray properties of the sample sources with radio observables. Results. We obtain a 100% (94%) detection fraction in the 0.5-2 keV (0.5-10 keV) energy band. GPS galaxy X-ray spectra are typically highly obscured ( N GPS H = 3 × 10 22 cm −2 ; σ N H 0.5 dex). The X-ray column density is larger than the HI column density measured in the radio by a factor 10 to 100. GPS galaxies lie well on the extrapolation to high radio powers of the correlation between radio and X-ray luminosity known in low-luminosity FR I radio galaxies. On the other hand, GPS galaxies exhibit a comparable X-ray luminosity to FR II radio galaxies, notwithstanding their much larger radio luminosity. Conclusions. The X-ray to radio luminosity ratio distribution in our sample is consistent with the bulk of the high-energy emission being produced by the accretion disk, as well as with dynamical models of GPS evolution where X-rays are produced by Compton upscattering of ambient photons. Further support to the former scenario comes from the location of GPS galaxies in the X-ray to O[iii] luminosity ratio versus N H plane. We propose that GPS galaxies are young radio sources, which would reach their full maturity as classical FR II radio galaxies. However, column densities ∼ > 10 22 cm −2 could lead to a significant underestimate of dynamical age determinations based on the hotspot recession velocity measurements.

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Section: Discussionsupporting

confidence: 83%

The X-ray view of giga-hertz peaked spectrum radio galaxies

Tengstrand

Guainazzi

Siemiginowska

et al. 2009

A&A

100

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“…The exact dependence of N H on LS has to be taken with caution since for the smallest sources T spin could be up to ∼ 8000 K and hence N H proportionally higher, while the largest sources could have c f < 1 and again N H could be higher. Note that Orienti, Morganti & Dallacasa (2006) find, in 4 out of 6 HFPs, N H quite lower than expected from the Pihlström et al (2003) relation. Perhaps T spin is higher than the adopted T spin = 100 K or these sources are so small that they lay all within the disk "central hole" and then could be seen through little H I (with the appropriate geometry).…”

Section: Results From Sample Integrated Valuesmentioning

confidence: 65%

“…Two (representative) "large" samples are worth mentioning: The interesting result found by both groups is the anticorrelation between N H and LS. Pihlström et al (2003), taking into account also the upper limits, give the relation N H = 7.2 × 10 19 LS −0.43 cm −2 (LS in kpc and T spin = 100 K). The extension to LSOs by Gupta et al (2006) would be useful to improve the fit, but it has too many upper limits, mostly above the value predicted by the previous relation, hence it doesn't constrain the parameters any further.…”

Section: Results From Sample Integrated Valuesmentioning

confidence: 99%

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Radio properties of CSSs and GPSs

Fanti¹

2009

Astron Nachr

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“…For instance, there is mounting evidence in the literature that the detection rate of Hi absorption in compact 'FR-0' radio galaxies is higher than that of their older, extended FR-I/II counterparts (e.g. Pihlström et al 2003;Curran et al 2013a;Aditya et al 2016). Curran et al proposed that this is due to a higher covering factor for compact sources, although different levels of sensitivity reached between surveys is another consideration.…”

Section: Detection Rate Of Hi Absorptionmentioning

confidence: 99%

Hi absorption in nearby compact radio galaxies

Glowacki

Allison

Sadler

et al. 2017

Mon. Not. R. Astron. Soc.

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Hi absorption studies yield information on both AGN feeding and feedback processes. This AGN activity interacts with the neutral gas in compact radio sources, which are believed to represent the young or recently re-triggered AGN population. We present the results of a survey for Hi absorption in a sample of 66 compact radio sources at 0.040 < z < 0.096 with the Australia Telescope Compact Array. In total, we obtained seven detections, five of which are new, with a large range of peak optical depths (3% to 87%). Of the detections, 71% exhibit asymmetric, broad (∆v FWHM > 100 km s −1 ) features, indicative of disturbed gas kinematics. Such broad, shallow and offset features are also found within low-excitation radio galaxies which is attributed to disturbed circumnuclear gas, consistent with early-type galaxies typically devoid of a gas-rich disk. Comparing mid-infrared colours of our galaxies with Hi detections indicates that narrow and deep absorption features are preferentially found in late-type and high-excitation radio galaxies in our sample. These features are attributed to gas in galactic disks. By combining XMM-Newton archival data with 21-cm data, we find support that absorbed X-ray sources may be good tracers of HI content within the host galaxy. This sample extends previous Hi surveys in compact radio galaxies to lower radio luminosities and provides a basis for future work exploring the higher redshift universe.

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The presence and distribution of H I absorbing gas in sub-galactic sized radio sources

Cited by 108 publications

References 57 publications

The X-ray view of giga-hertz peaked spectrum radio galaxies

The X-ray view of giga-hertz peaked spectrum radio galaxies

Radio properties of CSSs and GPSs

Hi absorption in nearby compact radio galaxies

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