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Related papers: MIGHTEE: exploring the relationship between spectr…

200 papers

We use the recent releases of sensitive VLA/LOFAR large-area surveys at 340 MHz and 54 MHz, in conjunction with the 1.4 GHz NVSS, to accurately determine the `spectral index - flux density relation' ($\alpha$ - S) for extragalactic radio…

Astrophysics of Galaxies · Physics 2023-07-05 Pratik Dabhade , Gopal-Krishna

We analyze optical and radio properties of radiogalaxies detected in the Sloan Digital Sky Survey (SDSS). The sample of radio sources are selected from the catalogue of Kimball & Ivezi\'c (2008) with flux densities at 325, 1400 and 4850…

Astrophysics of Galaxies · Physics 2015-05-18 Carlos G. Bornancini , Ana Laura O'Mill , Sebastian Gurovich , Diego Garcia Lambas

We present optical and/or near-IR images of 128 ultra steep spectrum (USS) radio sources. Roughly half of the objects are identified in the optical images (R <~ 24), while in the near-IR images, >94% are detected at K<~ 22. The mean…

An international team of researchers has come together to undertake an ultra-broadband exploration of the deep radio sky. The superMIGHTEE project combines data from the MIGHTEE project, using the precursor Square Kilometre Array (SKA)…

Astrophysics of Galaxies · Physics 2025-09-12 Dharam V. Lal , Russ Taylor , Srikrishna Sekhar , Ch. Ishwara-Chandra , Sushant Dutta , Sthabile Kolwa

This paper presents a new grid-based method for investigating the evolution of the steep-spectrum radio luminosity function, with the aim of quantifying the high-redshift cut-off suggested by previous work. To achieve this, the Combined…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-28 E. E. Rigby , P. N. Best , M. H. Brookes , J. A. Peacock , J. S. Dunlop , H. J. A. Röttgering , J. V. Wall , L. Ker

We present optical identifications and redshifts for seventeen new high-redshift radio sources. Fifteen of these sources are radio galaxies; the remaining two are high-redshift, steep-spectrum, radio-loud quasars. These objects were…

It has been known for nearly three decades that high redshift radio galaxies exhibit steep radio spectra, and hence ultra-steep spectrum radio sources provide candidates for high-redshift radio galaxies. Nearly all radio galaxies with z > 3…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-18 C. H. Ishwara-Chandra , S. K. Sirothia , Y. Wadadekar , S. Pal , R. Windhorst

The MeerKAT International GigaHertz Tiered Extragalactic Exploration (MIGHTEE) is one of the MeerKAT large survey projects, designed to pathfind SKA key science. MIGHTEE is undertaking deep radio imaging of four well observed fields…

Astrophysics of Galaxies · Physics 2023-12-21 A. R. Taylor , S. Sekhar , L. Heino , A. M. M. Scaife , J. Stil , M. Bowles , M. Jarvis , I. Heywood , J. D. Collier

In order to trace the instantaneous star formation rate at high redshift, and hence help understanding the relation between the different emission mechanisms related to star formation, we combine the recent 4 Ms Chandra X-ray data and the…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-03 S. Vattakunnel , P. Tozzi , F. Matteucci , P. Padovani , N. Miller , M. Bonzini , V. Mainieri , M. Paolillo , L. Vincoletto , W. N. Brandt , B. Luo , K. I. Kellermann , Y. Q. Xue

We present a sample of 1317 Infrared-Faint Radio Sources (IFRSs) that, for the first time, are reliably detected in the infrared, generated by cross-correlating the Wide-Field Infrared Survey Explorer (WISE) all-sky survey with major radio…

At the faintest radio flux densities (S_1.4 < 10 mJy), conflicting results have arisen regarding whether there is a flattening of the average spectral index between a low radio frequency (325 or 610 MHz), and e.g. 1.4 GHz. We present a new…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-03 Kate Randall , Andrew Hopkins , Ray Norris , Peter-Christian Zinn , Enno Middelberg , Minnie Mao , Rob Sharp

At bright radio powers ($P_{\rm 1.4 GHz} > 10^{25}$ W/Hz) the space density of the most powerful sources peaks at higher redshift than that of their weaker counterparts. This paper establishes whether this luminosity-dependent evolution…

Astrophysics of Galaxies · Physics 2015-09-16 E. E. Rigby , J. Argyle , P. N. Best , D. Rosario , H. J. A. Röttgering

Using the sample of radio selected BL Lacertae objects (RBLs) and X-ray selected BL Lacertae objects (XBLs) presented by Sambruna et al. (1996), we calculated the luminosities of radio, optical and X-ray of each source and made the…

Astrophysics · Physics 2009-11-07 D. C. Mei , L. Zhang , Z. J. Jiang , B. Z. Dai

Spectra have been obtained with the Infrared Spectrograph on the Spitzer Space Telescope for 18 optically faint sources (R > 23.9,mag) having f(nu) (24um) > 1.0,mJy and having radio detections at 20 cm to a limit of 115 microJy. Sources are…

Astrophysics · Physics 2009-11-13 D. W. Weedman , E. Le Floc'h , S. J. U. Higdon , J. L. Higdon , J. R. Houck

This study characterises the radio luminosity functions (RLFs) for SFGs and AGN using statistical redshift estimation in the absence of comprehensive spectroscopic data. Sensitive radio surveys over large areas detect many sources with…

The Dominion Radio Astrophysical Observatory Deep Field polarization study has been matched with the Spitzer Wide-Area Infrared Extragalactic survey of the European Large Area Infrared Space Observatory Survey North 1 field. We have used…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-27 Julie K. Banfield , Samuel J. George , A. Russ Taylor , Jeroen M. Stil , Roland Kothes , Douglas Scott

We use data from the Parkes Half-Jansky Flat-Spectrum (PHJFS) sample (Drinkwater et al. 1997) to constrain the cosmic evolution in the co-moving space density of radio sources in the top decade of the flat-spectrum radio luminosity function…

Astrophysics · Physics 2009-10-31 Matt J. Jarvis , Steve Rawlings

Unlike at lower redshift, where there is a 40% detection rate, surveys for 21-cm absorption arising within the hosts of z > 1 radio galaxies and quasars have been remarkably unsuccessful. Curran et al.(2008) suggest that this is due to the…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-11 S. J. Curran , M. T. Whiting , E. M. Sadler , C. Bignell

[Abridged] We study the evolution of the radio spectral index and far-infrared/radio correlation (FRC) across the star-formation rate-stellar masse (i.e. SFR-M*) plane up to z 2. We start from a M*-selected sample of galaxies with reliable…