A radio spectral index map and catalogue at 147–1400 MHz covering 80 per cent of the sky

Gasperin, F. de; Intema, H. T.; Frail, D. A.

doi:10.1093/mnras/stx3125

Cited by 97 publications

(85 citation statements)

References 91 publications

(103 reference statements)

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“…There is no clear correlation between α radio and redshift, which is consistent with previous works (Blundell et al 1999;Bornancini et al 2010;Calistro Rivera et al 2017). The mean value of α radio of 190 HSC-FIRST RGs is ∼0.73 that is consistent with what reported in de Gasperin et al (2018) who investigated radio spectral index over 80% of the sky based on the NVSS and TGSS. The mean values of α radio of the SDSS-and HSC-level objects are ∼0.72 and ∼0.74, respectively.…”

Section: Radio Spectral Indexsupporting

confidence: 91%

A Wide and Deep Exploration of Radio Galaxies with Subaru HSC (WERGS). II. Physical Properties Derived from the SED Fitting with Optical, Infrared, and Radio Data

Toba

Yamashita

Nagao

et al. 2019

ApJS

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We present physical properties of radio galaxies (RGs) with f 1.4GHz > 1 mJy discovered by Subaru Hyper Supreme-Cam (HSC) and VLA Faint Images of the Radio Sky at Twenty-Centimeters (FIRST) survey. For 1056 FIRST RGs at 0 < z ≤ 1.7 with HSC counterparts in about 100 deg 2 , we compiled multi-wavelength data of optical, near-infrared (IR), mid-IR, far-IR, and radio (150 MHz). We derived their color excess (E(B − V ) * ), stellar mass, star formation rate (SFR), IR luminosity, the ratio of IR and radio luminosity (q IR ), and radio spectral index (α radio ) that are derived from the SED fitting with CIGALE. We also estimated Eddington ratio based on stellar mass and integration of the best-fit SEDs of AGN component. We found that E(B − V ) * , SFR, and IR luminosity clearly depend on redshift while stellar mass, q IR , and α radio do not significantly depend on redshift. Since optically-faint (i AB ≥ 21.3) RGs that are newly discovered by our RG survey tend to be high redshift, they tend to not only have a large dust extinction and low stellar mass but also have high SFR and AGN luminosity, high IR luminosity, and high Eddington ratio compared to optically-bright ones. The physical properties of a fraction of RGs in our sample seem to differ from a classical view of RGs with massive stellar mass, low SFR, and low Eddington ratio, demonstrating that our RG survey with HSC and FIRST provides us curious RGs among entire RG population.

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Section: Radio Spectral Indexsupporting

confidence: 91%

A Wide and Deep Exploration of Radio Galaxies with Subaru HSC (WERGS). II. Physical Properties Derived from the SED Fitting with Optical, Infrared, and Radio Data

Toba

Yamashita

Nagao

et al. 2019

ApJS

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“…After classifying the pairs based on visual inspection of the images, the RM source positions from Taylor et al (2009) are cross-matched with the Hammond et al (2012) and Kimball & Ivezić (2008) catalogs, which include redshifts 3 . Hammond et al (2012) includes Taylor et al (2009) components cross-matched with spectroscopic redshifts from the SDSS data release 8 (Aihara et al 2011), the Six-degree Field Galaxy Survey (6dFGS, Jones et al 2004Jones et al , 2009), the Twodegree Field Galaxy Redshift Survey (2dFGRS, Colless et al 2001Colless et al , 2003, and the 2Df QSO Redshift Survey (2QZ) and 6dF QSO Redshift Survey (6Qz) (Croom et al 2004). Kimball & Ivezić (2014) cross matched NVSS components with spectroscopic redshifts from SDSS DR9 (Ahn et al 2012).…”

Section: Redshiftsmentioning

confidence: 99%

Differences in Faraday Rotation between Adjacent Extragalactic Radio Sources as a Probe of Cosmic Magnetic Fields

Vernstrom

Gaensler

Rudnick

et al. 2019

ApJ

112

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Faraday rotation measures (RMs) of extragalactic radio sources provide information on line-of-sight magnetic fields, including contributions from our Galaxy, source environments, and the intergalactic medium (IGM). Looking at differences in RMs, ∆RM, between adjacent sources on the sky can help isolate these different components. In this work, we classify adjacent polarized sources in the NVSS as random or physical pairs. We recompute and correct the uncertainties in the NVSS RM catalog, since these were significantly overestimated. Our sample contains 317 physical and 5111 random pairs, all with Galactic latitudes |b| ≥ 20 • , polarization fractions ≥ 2%, and angular separations between 1.5 and 20 . We find an rms ∆RM of 14.9 ± 0.4 rad m −2 and 4.6 ± 1.1 rad m −2 for random and physical pairs, respectively. This means polarized extragalactic sources that are close on the sky, but at different redshifts, have larger differences in RM than two components of one source. This difference of ∼ 10 rad m −2 is significant at 5σ, and persists in different data subsamples. While there have been other statistical studies of ∆RM between adjacent polarized sources, this is the first unambiguous demonstration that some of this RM difference must be extragalactic, thereby providing a firm upper limit on the RM contribution of the IGM. If the ∆RMs originate local to the sources, then the local magnetic field difference between random sources is a factor of two larger than between components of one source. Alternatively, attributing the difference in ∆RMs to the intervening IGM yields an upper limit on the IGM magnetic field strength of 40 nG.

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“…The first one shows a symmetric, off-axis emission directly linked to the core region. de Gasperin et al (2018) presented a spectral index catalogue built from TGSS and NVSS images (thus between 150 MHz and 1.4 GHz), covering ∼80% of the sky, at a declination > −40 • . For J0318+684, the angular resolution of the spectral index map provided by the catalogue is good enough to allow a characterization of the emission coming from the off-axis regions.…”

Section: Double-double and X-shaped Grgmentioning

confidence: 99%

Hard X-ray selected giant radio galaxies – II. Morphological evidence of restarted radio activity

Bruni

Panessa

Bassani³

et al. 2020

Monthly Notices of the Royal Astronomical Society

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About 6% of Radio Galaxies (RG) can reach linear sizes larger than 0.7 Mpc, and are then classified as Giant Radio Galaxies (GRG). The conditions that make possible the formation of such big structures is still not clear -either core accretion properties or environmental factors. Recent studies have shown that GRG can be up to four times more abundant in hard X-ray selected (i.e. from INTEGRAL/IBIS and Swift/BAT at >20 keV) RG samples. Moreover, a high fraction of young radio sources found in their cores suggests a recently restarted activity, as suggested from the discrepancy between the measured jet and lobes power, with respect to the one expected from core X-ray luminosity. Here we present a radio morphological study of a sample of 15 hard X-ray selected GRG, discussing low-frequency images from our GMRT campaign complemented with others from the literature: among them, 7/15 show evidence of restarted radio activity either in the form of double-double/X-shaped morphology, or as a cocoon emission embedding more recent jets. This, together with the objects from this sample already found hosting a young radio source in their core, suggests that at least 13 over 15 of these hard X-ray selected GRG show features which are consistent with the possibility of restarted radio activity.

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A radio spectral index map and catalogue at 147–1400 MHz covering 80 per cent of the sky

Cited by 97 publications

References 91 publications

A Wide and Deep Exploration of Radio Galaxies with Subaru HSC (WERGS). II. Physical Properties Derived from the SED Fitting with Optical, Infrared, and Radio Data

A Wide and Deep Exploration of Radio Galaxies with Subaru HSC (WERGS). II. Physical Properties Derived from the SED Fitting with Optical, Infrared, and Radio Data

Differences in Faraday Rotation between Adjacent Extragalactic Radio Sources as a Probe of Cosmic Magnetic Fields

Hard X-ray selected giant radio galaxies – II. Morphological evidence of restarted radio activity

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