The R-band Hubble diagram for gigahertz peaked spectrum radio galaxies

Snellen, I. A. G.; Bremer, M. N.; Schilizzi, R. T.; Miley, G. K.; Ojik, R. van

doi:10.1093/mnras/279.4.1294

Cited by 45 publications

(61 citation statements)

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“…For sources without a spectroscopic redshift, we used the Hubble-K or Hubble-R relations to estimate the redshift (Willott et al 2003;Snellen et al 1996;de Vries et al 2007). Spectral index maps were also made for the radio sources.…”

Section: Resultsmentioning

confidence: 99%

“…The images for each IF were combined into a deep Notes. (a) flux from NVSS (Condon et al 1998);(b) identification of the cD galaxy uncertain; (c) flux from WENSS (Rengelink et al 1997); (d) redshift estimated using the fitted Hubble-R relation from de Vries et al (2007), since it is unclear whether there is a common underlying population of massive elliptical galaxies for extended steep-spectrum radio sources we have taken the 3C Hubble-R relation from Snellen et al (1996) as an upper limit for the redshift (i.e., the 3C galaxies are about 1 mag brighter at the same redshift); (e) redshift estimated using the fitted Hubble-K relation from Willott et al (2003); ( f ) varies across the source; (g) association with cluster uncertain; (h) PHNX = radio phoenix, AGNR = AGN relic, MH = radio mini-halo, DSAR = relic tracing shock wave with DSA.…”

Section: Wsrt 13-17 Ghz Observations Of 24p73mentioning

confidence: 99%

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Diffuse steep-spectrum sources from the 74 MHz VLSS survey

Weeren

Röttgering

Brüggen

2011

A&A

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Context. Galaxy clusters grow by a sequence of mergers with other clusters and galaxy groups. During these mergers, shocks and/or turbulence are created within the intracluster medium (ICM). In this process, particles could be accelerated to highly relativistic energies. The synchrotron radiation from these particles is observed in the form of radio relics and halos that are generally characterized by a steep radio spectral index. Shocks can also revive fossil radio plasma from a previous episode of AGN activity, creating a socalled radio "phoenix". Here we present multi-frequency radio observations of diffuse steep-spectrum radio sources selected from the 74 MHz VLSS survey. Previous Giant Metrewave Radio Telescope (GMRT) observations showed that some of these sources had filamentary and elongated morphologies, which are expected for radio relics. Aims. We attempt to understand the nature of diffuse steep-spectrum radio sources and characterize their spectral index and polarization properties. Methods. We carried out radio continuum observations at 325 MHz with the GMRT. Observations with the Very Large Array (VLA) and Westerbork Synthesis Radio Telescope (WSRT) were taken at 1.4 GHz in full polarization mode. Optical images around the radio sources were taken with the William Herschel and Isaac Newton Telescope (WHT, INT). Results. Most of the sources in our sample consist of old radio plasma from AGNs located in small galaxy clusters. The sources can be classified as AGN relics or radio phoenices. The spectral indices across most of the radio sources display large variations. Conclusions. We conclude that diffuse steep-spectrum radio sources are not only found in massive X-ray luminous galaxy clusters but also in smaller systems. Future low-frequency surveys will uncover large numbers of steep-spectrum radio relics related to previous episodes of AGN activity.

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Section: Resultsmentioning

confidence: 99%

Section: Wsrt 13-17 Ghz Observations Of 24p73mentioning

confidence: 99%

Diffuse steep-spectrum sources from the 74 MHz VLSS survey

Weeren

Röttgering

Brüggen

2011

A&A

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“…b References for the data used to derive the bolometric luminosities. c References for the BH masses and the apparent magnitude of the host galaxies in R−band used to estimate the BH masses in this work, of which (1) and (2) are selected from Snellen et al (1996) and NED (NASA/IPAC Extragalactic Database; http://nedwww.ipac.caltech.edu) respectively. therein), while the ages estimated from synchrotron cooling time mainly are taken from Murgia et al (1999).…”

Section: Notesmentioning

confidence: 99%

Observational Evidence for Young Radio Galaxies Is Triggered by Accretion Disk Instability

2009

ApJ

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Bolometric luminosities and black hole (BH) masses are estimated by various methods for a sample of young radio galaxies with known ages. We find that the ages are positively correlated with the bolometric luminosities in these young radio galaxies. This positive correlation is consistent with the theoretical prediction based on the radiation pressure instability of accretion disks in Czerny et al. The ages of young radio galaxies are also found to be consistent with the theoretical durations of outbursts in BH mass and accretion rate (in Eddington unit) plane, where the outbursts are assumed to be triggered by the radiation pressure instabilities. Our results provide observational evidence for the radiation pressure instability, which causes limitcycle behavior, as a physical mechanism that may be responsible for these short-lived young radio galaxies.

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“…The answer to this question is not yet apparent. On one hand, there should be a continuum of properties, and along these lines recent papers indicate that both CSOs and larger scale PRGs reside in bright elliptical galaxies with predominantly old stellar populations (de Vries et al 1998a(de Vries et al , 1998b(de Vries et al , 2000Snellen et al 1996Snellen et al , 1998OÏDea et al 1996a). Yet if mergers play a signiÐcant role in triggering nuclear activity (see, e.g., Wilson & Colbert 1995), one might expect more dense nuclear interstellar media and unusual nuclear kinematics in the youngest AGNs.…”

Section: Introductionmentioning

confidence: 98%

Host Galaxies, Obscuration, and Nuclear Structure of Three Nearby Compact Symmetric Objects

Perlman

Stocke

Conway

et al. 2001

The Astronomical Journal

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We present three-band Hubble Space T elescope imaging of three nearby (z ¹ 0.1) compact symmetric objects : 4C 31. 04, 1946]708, and 1146]596. These objects were chosen on the basis of proximity to Earth as well as H I 21 cm line absorption. The inner H-band isophotes of these galaxies are well Ðtted by Nuker models, typical of nearby elliptical galaxies. Each shows a signiÐcant Ñattening in the isophotal proÐle at radii as well as signiÐcant variations in ellipticity and P.A. However, as previous D0A .5, authors have noted, neither is uncommon for elliptical galaxies. All three objects show modest departures from Nuker law models at radii of 1È5 kpc. Each galaxy shows large well-distributed dust h 60 1 features, which are somewhat concentrated in the nuclear regions in features that resemble disks or tori. We Ðnd that the amount of dust in these galaxies is about 10 times higher than normal for elliptical galaxies and radio galaxy hosts. The major axes of the nuclear dust disks tend to be oriented roughly perpendicular to the radio axis. One galaxy, 4C 31.04, exhibits bright nuclear regions well aligned with the radio axis, while another, 1146]596, shows a signiÐcant near-IR excess resembling a stellar bar along its dust disk. The combination of outwardly normal isophotal proÐles with signiÐcant variations in P.A. and ellipticity is consistent with the host galaxies being relatively recent merger remnants and the mergers having occurred yr ago. Such a merger could have "" triggered ÏÏ the onset of the current Z108 active phase seen in these objects, but our data require a signiÐcant time delay between the merger event and the onset of nuclear activity. However, these data are also consistent with the hypothesis that the onset of nuclear activity in radio galaxies is due to relatively minor "" feeding ÏÏ events and/or the formation of "" bars within bars,ÏÏ events which would disturb the internal kinematics only slightly.

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The R-band Hubble diagram for gigahertz peaked spectrum radio galaxies

Cited by 45 publications

References 0 publications

Diffuse steep-spectrum sources from the 74 MHz VLSS survey

Diffuse steep-spectrum sources from the 74 MHz VLSS survey

Observational Evidence for Young Radio Galaxies Is Triggered by Accretion Disk Instability

Host Galaxies, Obscuration, and Nuclear Structure of Three Nearby Compact Symmetric Objects

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