Complete identification of the Parkes half-Jansky sample of GHz peaked spectrum radio galaxies

Vries, Nathan de; Snellen, I. A. G.; Schilizzi, R. T.; Lehnert, M. D.; Bremer, M. N.

doi:10.1051/0004-6361:20066506

Cited by 30 publications

(31 citation statements)

References 30 publications

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“…13). Although we do not have a spectroscopic redshift for this galaxy, the (i) color and (ii) R and K magnitudes are in agreement with a subcluster located at the same redshift as the western subcluster (e.g., Willott et al 2003;de Vries et al 2007). The same is true for the other massive elliptical galaxies found in both subclusters, see Sect.…”

Section: Thermal Icm and Galaxy Distributionmentioning

confidence: 67%

A double radio relic in the merging galaxy cluster ZwCl 0008.8+5215

Weeren

Hoeft

Röttgering

et al. 2011

A&A

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Context. Some merging galaxy clusters host diffuse elongated radio sources, also called radio relics. It is proposed that these radio relics trace shock waves in the intracluster medium (ICM) created during a cluster merger event. Within the shock waves particles are accelerated to relativistic energies, and in the presence of a magnetic field synchrotron radiation will be emitted. Here we present giant metrewave radio telescope (GMRT) and Westerbork synthesis radio telescope (WSRT) observations of a new double relic in the galaxy cluster ZwCl 0008.8+5215. Aims. The aim of the observation is to understand the phenomenon of radio relics. Methods. We carried out radio continuum observations at 241 and 610 MHz with the GMRT, and 1.3−1.8 GHz observations with the WSRT in full polarization mode. Optical V, R, and I band images of the cluster were taken with the 2.5 m Isaac Newton Telescope (INT). An optical spectrum, to determine the redshift of the cluster, was taken with the William Herschel Telescope (WHT). Results. Our observations show the presence of a double radio relic in the galaxy cluster ZwCl 0008.8+5215, for which we find a spectroscopic redshift of z = 0.1032 ± 0.0018 from an optical spectrum of one of the cD galaxies. The spectral index of the two relics steepens inwards to the cluster center. For part of the relics, we measure a polarization fraction in the range ∼5−25%. A ROSAT X-ray image displays an elongated ICM and the large-scale distribution of galaxies reveals two cluster cores, all pointing towards a binary cluster merger event. The radio relics are located symmetrically with respect to the X-ray center of the cluster, along the proposed merger axis. The relics have a linear extent of 1.4 Mpc and 290 kpc. This factor of five difference in linear size is unlike that of previously known double relic systems, for which the sizes do not differ by more than a factor of two. Conclusions. We conclude that the double relics in ZwCl 0008.8+5215 are best explained by two outward moving shock waves in which particles are (re)accelerated trough the diffusive shock acceleration (DSA) mechanism.

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Section: Thermal Icm and Galaxy Distributionmentioning

confidence: 67%

A double radio relic in the merging galaxy cluster ZwCl 0008.8+5215

Weeren

Hoeft

Röttgering

et al. 2011

A&A

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“…Before addressing the nature of the UV emission, we describe the properties of this emission in relation to other properties, for the individual sample sources. We note that optical observations of the higher redshift Parkes half-Jansky sample suggest that the rest frame UV may contain a contribution from a young stellar population (de Vries et al 2007). …”

Section: Uv Morphologymentioning

confidence: 79%

Star formation in the hosts of GHz peaked spectrum and compact steep spectrum radio galaxies

Labiano¹,

O’Dea

Barthel³

et al. 2007

A&A

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Aims. We are searching for star formation regions in the hosts of potentially young radio galaxies (gigahertz peaked spectrum and compact steep spectrum sources). Methods. We used near-UV imaging with the Hubble Space Telescope Advanced Camera for Surveys. Results. We find near-UV light could be the product of recent star formation in five of the nine observed sources, though other explanations are not currently ruled out. An additional two sources show marginal detections. The UV luminosities of the GPS and CSS sources are similar to those of a sample of nearby large-scale radio galaxies. Stellar-population synthesis models are consistent with a burst of recent star formation occurring before the formation of the radio source. However, observations at other wavelengths and colors are needed to definitively establish the nature of the observed UV light. In the CSS source 1443+77, the near-UV light is aligned with and is co-spatial with the radio source. We suggest that the UV light in this source is produced by star formation triggered and/or enhanced by the radio source.

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“…For sources without a spectroscopic redshift, but having SDSS DR7 coverage we took the SDSS photometric redshift. For other sources we used that K and R magnitudes of massive elliptical galaxies correlate with redshift (K − z and R − z relations, e.g., Willott et al 2003;de Vries et al 2007). …”

Section: Resultsmentioning

confidence: 99%

A search for steep spectrum radio relics and halos with the GMRT

Weeren¹,

Röttgering²,

Brüggen

et al. 2009

A&A

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Context. Diffuse radio emission, in the form of radio halos and relics, traces regions in clusters with shocks or turbulence, probably produced by cluster mergers. The shocks and turbulence are important for the total energetics and detailed temperature distribution within the intracluster medium (ICM). Only a small fraction of clusters exhibit diffuse radio emission, whereas a large majority of well-studied clusters shows clear substructure in the ICM. Some models of diffuse radio emission in clusters indicate that virtually all clusters should contain diffuse radio sources with a steep spectrum. External accretion shocks associated with filamentary structures of galaxies could also accelerate electrons to relativistic energies and hence produce diffuse synchrotron emitting regions. The detection of radio emission from such filaments is important for our understanding of the origin of the Warm-Hot Intergalactic Medium (WHIM), and relativistic electrons and magnetic fields in the cosmic web. Here we report on Giant Metrewave Radio Telescope (GMRT) observations of a sample of steep spectrum sources from the 74 MHz VLSS survey. These sources are diffuse on scales > ∼ 15 , and not clearly associated with nearby (z < ∼ 0.1) galaxies. Aims. The main aim of the observations is to search for diffuse radio emission associated with galaxy clusters or the cosmic web. Methods. We have carried out GMRT 610 MHz continuum observations of unidentified diffuse steep spectrum sources. Results. We have constructed a sample of diffuse steep spectrum sources, selected from the 74 MHz VLSS survey. We identified eight diffuse radio sources probably all located in clusters. We found five radio relics, one cluster with a giant radio halo and a radio relic, and one radio mini-halo. The giant radio halo has the highest radio power (P 1.4 ) known to date. By complementing our observations with measurements from the literature we find correlations between the physical size of relics and the spectral index, in the sense that smaller relics have steeper spectra. Furthermore, larger relics are mostly located in the outskirts of clusters while smaller relics are located closer to the cluster center.

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Complete identification of the Parkes half-Jansky sample of GHz peaked spectrum radio galaxies

Cited by 30 publications

References 30 publications

A double radio relic in the merging galaxy cluster ZwCl 0008.8+5215

A double radio relic in the merging galaxy cluster ZwCl 0008.8+5215

Star formation in the hosts of GHz peaked spectrum and compact steep spectrum radio galaxies

A search for steep spectrum radio relics and halos with the GMRT

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