A new sample of giant radio galaxies from the WENSS survey

Schoenmakers, A. P.; Bruyn, A. G. de; Röttgering, H. J. A.; Laan, H. van der

doi:10.1051/0004-6361:20010746

Cited by 116 publications

(153 citation statements)

References 14 publications

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“…There is no indication of diffuse emission in total intensity. A circle marks a region around the giant radio galaxy J162740+514012 (see Schoenmakers et al 2001), which contains two lobes that were found to be highly polarized at 325 MHz. The source is found to be polarized in the LOFAR band as well, although at much lower levels.…”

Section: Widefield Image In Total Intensitymentioning

confidence: 99%

Initial LOFAR observations of epoch of reionization windows

Jelić

Bruyn

Mevius

et al. 2014

A&A

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Aims. This study aims to characterise the polarized foreground emission in the ELAIS-N1 field and to address its possible implications for extracting of the cosmological 21 cm signal from the LOw-Frequency ARray -Epoch of Reionization (LOFAR-EoR) data. Methods. We used the high band antennas of LOFAR to image this region and RM-synthesis to unravel structures of polarized emission at high Galactic latitudes. Results. The brightness temperature of the detected Galactic emission is on average ∼4 K in polarized intensity and covers the range from -10 to +13 rad m −2 in Faraday depth. The total polarized intensity and polarization angle show a wide range of morphological features. We have also used the Westerbork Synthesis Radio Telescope (WSRT) at 350 MHz to image the same region. The LOFAR and WSRT images show a similar complex morphology at comparable brightness levels, but their spatial correlation is very low. The fractional polarization at 150 MHz, expressed as a percentage of the total intensity, amounts to ≈1.5%. There is no indication of diffuse emission in total intensity in the interferometric data, in line with results at higher frequencies Conclusions. The wide frequency range, high angular resolution, and high sensitivity make LOFAR an exquisite instrument for studying Galactic polarized emission at a resolution of ∼1-2 rad m −2 in Faraday depth. The different polarized patterns observed at 150 MHz and 350 MHz are consistent with different source distributions along the line of sight wring in a variety of Faraday thin regions of emission. The presence of polarized foregrounds is a serious complication for epoch of reionization experiments. To avoid the leakage of polarized emission into total intensity, which can depend on frequency, we need to calibrate the instrumental polarization across the field of view to a small fraction of 1%.

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Section: Widefield Image In Total Intensitymentioning

confidence: 99%

Initial LOFAR observations of epoch of reionization windows

Jelić

Bruyn

Mevius

et al. 2014

A&A

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“…The source 3C 35 is included in the sample of 47 low redshift (z < 0.4) GRG obtained by Schoenmakers et al (2001) using the Westerbork Northern Sky Survey (WENSS) of the sky above +30 • of declination at 325 MHz (Rengelink et al 1997). The criteria for the sample specified that a candidate GRG must 1 Throughout we adopt H 0 = 71 km s −1 Mpc −1 , Ω m = 0.27, Ω Λ = 0.73 (Spergel et al 2003).…”

Section: Radio Datamentioning

confidence: 99%

Low-frequency study of two giant radio galaxies: 3C 35 and 3C 223

Orrù

Murgia

Feretti

et al. 2010

A&A

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Aims. Radio galaxies with a projected linear size > ∼ 1 Mpc are classified as giant radio sources. According to the current interpretation these are old sources which have evolved in a low-density ambient medium. Because radiative losses are negligible at low frequency, extending spectral aging studies in this frequency range will allow us to determine the zero-age electron spectrum injected and then to improve the estimate of the synchrotron age of the source. Methods. We present Very Large Array images at 74 MHz and 327 MHz of two giant radio sources: 3C 35 and 3C 223. We performed a spectral study using 74, 327, 608 and 1400 GHz images. The spectral shape is estimated in different positions along the source. Results. The radio spectrum follows a power-law in the hotspots, while in the inner region of the lobe the shape of the spectrum shows a curvature at high frequencies. This steepening agrees with synchrotron aging of the emitting relativistic electrons. In order to estimate the synchrotron age of the sources, the spectra were fitted with a synchrotron model of emission. They show that 3C 35 is an old source of 143 ± 20 Myr, while 3C 223 is a younger source of 72 ± 4 Myr.

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“…North HS is a radio hot spot to the north. The combined 1998 and1999 (416) a Redshift of the absorber. Model A assumes that the entire absorption is related to the Galaxy, whiles models B, C, and D assume that the Galactic column is constant at 4:18 Â 10 20 atoms cm À2 and the additional absorption comes from the intervening absorber at a given, fixed redshift.…”

Section: X-ray Emission Within 10mentioning

confidence: 99%

“…Until recently, most GPS/CSS sources were thought to be very compact, with the radio emission contained within $1-10 kpc of the core. About $25% of GPS/CSS sources exhibit faint extended radio emission on scales larger than the size of the host galaxy Stanghellini et al 1990;O'Dea 1998;Fanti et al 2001), with only a few sources showing any radio structures on Mpc scales (Schoenmakers et al 1999;Siemiginowska et al 2002;Marecki et al 2003). This extended radio emission is amorphous or jetlike, but is usually hard to classify because it is weak.…”

Section: Introductionmentioning

confidence: 99%

ChandraDiscovery of an X‐Ray Jet and Extended X‐Ray Structure in thez= 0.63 Quasar B2 0738+313

Siemiginowska

Stanghellini

Brunetti

et al. 2003

ApJ

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We have made a $30 ks Chandra observation of the redshift z ¼ 0:63 gigahertz-peaked spectrum (GPS) quasar B2 0738+313. We detected X-ray emission from the core and have discovered a 200 kpc (projected on the sky) X-ray jet. The X-ray jet is narrow and curves, following the extended radio structure to the south of the quasar, and ending with a hot spot at the southernmost part of the radio lobe. The jet has a knot at $13 00 away from the core. The knot emission is consistent with the X-rays being created by the inverse Compton scattering of the cosmic microwave background (CMB) photons and requires jet bulk Lorentz factors of a few (À bulk $ 5 7). We discuss the emission mechanisms that may be responsible for the jet emission. We present new VLA data of the core and jet, and discuss the relation between the extended radio and X-ray emission. Extended emission observed in several GPS sources has been interpreted as a signature of the source past activity, while the GPS source is young and newly expanded. We argue that B2 0738+313 may be an example of a new class of radio sources similar to the FR II radio galaxies in their high jet bulk velocities, but with a powerful GPS-like nucleus. B2 0738+313 also has two damped Ly systems along the line of sight, at z abs ¼ 0:0912 and 0.2212. We discuss the possible connection between the X-ray absorption (7:2 AE 0:9 Â 10 20 cm À2 ) detected in the ACIS spectrum and these two intervening absorbers. We also investigate an extended structure within the central 10 00 of the core in the relation to structure seen in the optical.

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A new sample of giant radio galaxies from the WENSS survey

Cited by 116 publications

References 14 publications

Initial LOFAR observations of epoch of reionization windows

Initial LOFAR observations of epoch of reionization windows

Low-frequency study of two giant radio galaxies: 3C 35 and 3C 223

ChandraDiscovery of an X‐Ray Jet and Extended X‐Ray Structure in thez= 0.63 Quasar B2 0738+313

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