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Related papers: Variability of sub-mJy radio sources

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We consider the high radio frequency (15 GHz - 353 GHz) properties and variability of 35 Brightest Cluster Galaxies (BCGs). These are the most core-dominated sources drawn from a parent sample of more than 700 X-ray selected clusters, thus…

We present the first results from a recently concluded study of GRBs at $z\gtrsim5$ with the Karl G. Jansky Very Large Array (VLA). Spanning $1$ to $85.5$ GHz and 7 epochs from 1.5 to 82.3 d, our observations of GRB 140311A are the most…

High Energy Astrophysical Phenomena · Physics 2018-06-06 Tanmoy Laskar , Edo Berger , Ryan Chornock , Raffaella Margutti , Wen-fai Fong , Ashley Zauderer

We have conducted a deep survey (r.m.s noise 17 microJy) with the Very Large Array (VLA) at 1.4 GHz, with a resolution of 6 arcsec, of a 1 square degree region included in the VIRMOS VLT Deep Survey. In the same field we already have…

This is the second of two papers describing the observations and source catalogues derived from sensitive 3-GHz images of the Lockman Hole North using the Karl G. Jansky Very Large Array. We describe the reduction and cataloguing process,…

Astrophysics of Galaxies · Physics 2016-08-31 Tessa Vernstrom , Douglas Scott , Jasper Wall , Jim Condon , Bill Cotton , Ken Kellermann , Rick Perley

Results of two years of continuous monitoring of flux density variations at 8.3 and 2.3 GHz of the Galactic Center super-massive black hole candidate Sgr A* are reported. The average RMS modulation indices are 6% and 2.5% at 8.3 & 2.3 GHz…

Astrophysics · Physics 2007-05-23 Heino Falcke

We report on a comprehensive radio monitoring program of the bright gamma-ray burster GRB970111. These VLA observations were made at a frequency of 1.4 GHz and span a range of post-burst timescales between 28 hours and one month. Despite…

In our first paper we described three regions of the 9C survey of radio sources with the Ryle telescope at 15.2 GHz, constituting a total area of 520 deg^2 to a completeness limit of approximately 25 mJy. Here we report on a series of…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-13 E. M. Waldram , G. G. Pooley , M. L. Davies , K. J. B. Grainge , P. F. Scott

Sgr A* is variable at radio and submillimeter wavelengths on hourly time scales showing time delays between the peaks of flare emission as well as linearly polarized emission at millimeter and sub-mm wavelengths. To determine the…

Astrophysics · Physics 2009-11-13 F. Yusef-Zadeh , M. Wardle , W. D. Cotton , C. O. Heinke , D. A. Roberts

A complete, flux density limited sample of 96 faint ($> 0.5$ mJy) radio sources is selected from the 10C survey at 15.7 GHz in the Lockman Hole. We have matched this sample to a range of multi-wavelength catalogues, including SERVS, SWIRE,…

Astrophysics of Galaxies · Physics 2015-09-30 I. H. Whittam , J. M. Riley , D. A. Green , M. J. Jarvis , M. Vaccari

The compact radio source Sgr\,A*, associated with the super massive black hole at the center of the Galaxy, has been studied with VLBA observations at 3 frequencies (22, 43, 86\,GHz) performed on 10 consecutive days in May 2007. The total…

Astrophysics of Galaxies · Physics 2015-05-20 R. -S. Lu , T. P. Krichbaum , A. Eckart , S. König , D. ~Kunneriath , G. Witzel , A. Witzel , J. A. Zensus

We present preliminary results from a VLBI survey at $\lambda=6 $cm of a sample of 35 sources with flux densities of 2 - 100 mJy. These sources were selected from the VLA FIRST survey at $\lambda = 20 $cm, in a 3 degree field around the…

Astrophysics · Physics 2009-10-31 S. T. Garrington , M. A. Garrett , A. Polatidis

Spectral variability of radio sources encodes information about the conditions of intervening media, source structure, and emission processes. With new low-frequency radio interferometers observing over wide fractional bandwidths, studies…

Astrophysics of Galaxies · Physics 2020-12-23 K. Ross , J. R. Callingham , N. Hurley-Walker , N. Seymour , P. Hancock , T. M. O. Franzen , J. Morgan , S. V. White , M. E. Bell , P. Patil

Using three epochs of VLA observations of the Galactic Plane in the first quadrant taken ~15 years apart, we have conducted a search for a population of variable Galactic radio emitters in the flux density range 1-100 mJy at 6 cm. We find…

Astrophysics of Galaxies · Physics 2015-05-18 Robert H. Becker , David J. Helfand , Richard L. White , Deanne D. Proctor

The fields chosen for the first observations of the cosmic microwave background with the Very Small Array have been surveyed with the Ryle Telescope at 15 GHz. We have covered three regions around RA 00h20m Dec +30deg, RA 09h40m Dec +32deg…

Remnant radio galaxies represent an important phase in the life-cycle of radio active galactic nuclei. It is suggested that in this phase, the jets have switched off and the extended emission is fading rapidly. This phase is not…

Astrophysics of Galaxies · Physics 2021-09-22 N. Jurlin , M. Brienza , R. Morganti , Y. Wadadekar , C. H. Ishwara-Chandra , N. Maddox , V. Mahatma

We have employed the GMRT and the VLA to map the Lockman Hole. At 610 and 1,400 MHz, we reach noise levels of 15 and 6 uJy/beam, respectively, with well-matched resolutions (~5"). At this depth we obtained reliable detections for about half…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-14 Edo Ibar , R. J. Ivison , P. N. Best , K. Coppin , A. Pope , Ian Smail , J. S. Dunlop

We present the results of a 5 GHz survey with the Very Large Array, designed to search for short-lived (<1 day) transients and to characterize the variability of radio sources at milli-Jansky levels. A total sky area of 2.66 deg^2, spread…

High Energy Astrophysical Phenomena · Physics 2015-05-27 E. O. Ofek , D. A. Frail , B. Breslauer , S. R. Kulkarni , P. Chandra , A. Gal-Yam , M. M. Kasliwal , N. Gehrels

We present the first sub-mJy ($\approx0.7$ mJy beam$^{-1}$) survey to be completed below 100 MHz, which is over an order of magnitude deeper than previously achieved for widefield imaging of any field at these low frequencies. The high…

We report on the discovery of a variable radio source, VLA J070238.0+385044, associated with the proposed x-ray counterpart, 1SAX J0702.6+3850 of GRB 980329. The source was monitored from one day after the burst to one month later at…

Astrophysics · Physics 2009-10-30 G. B. Taylor , D. A. Frail , S. R. Kulkarni , D. S. Shepherd , M. Feroci , F. Frontera