An Updated Multi-Wavelength Radio and Optical Catalog of Quasars and Radio Galaxies

AbstractWe present a catalog of millions of radio sources, created by consolidating large-area radio and optical surveys GB6 (6cm), FIRST (20cm), NVSS (20cm), WENSS (92cm), VLSS (4m), and SDSS DR9 (optical). The region where all surveys overlap covers 3269 deg2 in the North Galactic Cap, and contains >160,000 20-cm sources, with about 12,000 detected in all five radio surveys and over one-third detected optically. Combining parameters from the sky surveys allows easy and efficient classification by radio and optical morphology and radio spectral index. The catalog is available at http://www.atnf.csiro.au/people/Amy.Kimball/radiocat.shtml.

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G279.0+1.1: a new extended source of high-energy gamma-rays

Monthly Notices of the Royal Astronomical Society ◽

10.1093/mnras/staa244 ◽

2020 ◽

Vol 492 (4) ◽

pp. 5980-5986

Author(s):

M Araya

Keyword(s):

Spectral Index ◽

Gamma Rays ◽

Gamma Ray ◽

High Energy ◽

Particle Spectrum ◽

Large Area ◽

Extended Source ◽

The North ◽

Energy Gamma ◽

High Energy Emission

ABSTRACT G279.0+1.1 is a supernova remnant (SNR) with poorly known parameters, first detected as a dim radio source and classified as an evolved system. An analysis of data from the Fermi-Large Area Telescope (LAT) revealing for the first time an extended source of gamma-rays in the region is presented. The diameter of the GeV region found is ${\sim} 2{^{\circ}_{.}}8$, larger than the latest estimate of the SNR size from radio data. The gamma-ray emission covers most of the known shell and extends further to the north and east of the bulk of the radio emission. The photon spectrum in the 0.5–500 GeV range can be described by a simple power law, $\frac{\mathrm{ d}N}{\mathrm{ d}E} \propto E^{-\Gamma }$, with a spectral index of Γ = 1.86 ± 0.03stat ± 0.06sys. In the leptonic scenario, a steep particle spectrum is required and a distance lower than the previously estimated value of 3 kpc is favoured. The possibility that the high-energy emission results from electrons that already escaped the SNR is also investigated. A hadronic scenario for the gamma-rays yields a particle spectral index of ∼2.0 and no significant constraints on the distance. The production of gamma-rays in old SNRs is discussed. More observations of this source are encouraged to probe the true extent of the shell and its age.

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The Performance of Neural Networks in Astronomical Image Classification

Symposium - International Astronomical Union ◽

10.1017/s0074180900047380 ◽

1994 ◽

Vol 161 ◽

pp. 235-241

Author(s):

S.C. Odewahn

Keyword(s):

Neural Network ◽

Image Classification ◽

Sky Surveys ◽

Pattern Recognition Techniques ◽

The North ◽

Astronomical Image ◽

Sky Survey ◽

Network Pattern ◽

North Galactic

The use of neural network pattern recognition techniques in the field of astronomy is reviewed. In assessing the quality of image recognition derived from this method particular attention is given to the problem of star/galaxy discrimination in large digital sky surveys. A two color survey of 9 fields of the first epoch Palomar Sky Survey, centered on the North Galactic Pole, has been performed with the Minnesota Automated Plate Scanner. A set of neural network image classifiers are used to automatically perform star/galaxy discrimination. We assess the efficiency of image classification and sample completeness through comparisons with a variety of independent studies of the NGP area.

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First Results from the VLA FIRST Survey

Symposium - International Astronomical Union ◽

10.1017/s007418090008164x ◽

1996 ◽

Vol 175 ◽

pp. 499-502

Author(s):

R.H. Becker ◽

M.D. Gregg ◽

D.J. Helfand ◽

C.M. Cress ◽

R. Mcmahon ◽

...

Keyword(s):

Correlation Function ◽

Radio Sources ◽

Optical Identification ◽

X Ray ◽

The North ◽

First Results ◽

Angular Correlation Function ◽

Second Year ◽

North Galactic ◽

Followup Studies

The VLA FIRST survey is now in its second year. We have completed mapping over 1500 deg2 of the North Galactic Cap and present here the catalog of the 138,000 radio sources detected therein. We discuss the statistics of this new catalog including the two-point angular correlation function for all radio emitters, present our optical identification of 24,000 sources using the APM catalog, and report followup studies on radio variability, X-ray source identification, and our bright quasar sample.

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Extragalactic jets as probes of distant clusters of galaxies and the clusters occupied by bent radio AGN (COBRA) survey

Proceedings of the International Astronomical Union ◽

10.1017/s1743921315002410 ◽

2014 ◽

Vol 10 (S313) ◽

pp. 315-320

Author(s):

Elizabeth L. Blanton ◽

Rachel Paterno-Mahler ◽

Joshua D. Wing ◽

M. L. N. Ashby ◽

Emmet Golden-Marx ◽

...

Keyword(s):

Radio Galaxies ◽

Radio Sources ◽

Clusters Of Galaxies ◽

Wide Range ◽

Extragalactic Jets ◽

Large Survey ◽

Kinetic Mode ◽

Group Environments ◽

Initial Results ◽

Quasars And Radio Galaxies

AbstractWe are conducting a large survey of distant clusters of galaxies using radio sources with bent jets and lobes as tracers. These radio sources are driven by AGN and achieve their bent morphologies through interaction with the surrounding gas found in clusters of galaxies. Based on low-redshift studies, these types of sources can be used to identify clusters very efficiently. We present initial results from our survey of 653 bent-double radio sources with optical hosts too faint to appear in the SDSS. The sample was observed in the infrared with Spitzer, and it has revealed ~200 distant clusters or proto-clusters in the redshift range z ~ 0.7 - 3.0. The sample of bent-doubles contains both quasars and radio galaxies enabling us to study both radiative and kinetic mode feedback in cluster and group environments at a wide range of redshifts.

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Observations of Straight-angle Tailed Radio Galaxies in Rich Clusters of Galaxies

Symposium - International Astronomical Union ◽

10.1017/s0074180900081067 ◽

1996 ◽

Vol 175 ◽

pp. 349-350

Author(s):

Aileen A. O'Donoghue ◽

Jean A. Eilek ◽

Frazer N. Owen

Keyword(s):

Spectral Index ◽

Radio Galaxies ◽

Radio Sources ◽

Clusters Of Galaxies ◽

Data Set ◽

Dynamical Properties

We have begun VLA observations of straight-angle tailed radio sources (SATs) at 1.5 and 4.8 GHz (L and C band) to achieve one arcsecond resolution at each frequency. This will provide a SAT data set similar to the O'Donoghue, Owen, and Eilek (1990) WAT data set with both total intensity and spectral index information. We will use these data to examine morphological and dynamical properties of straight-tailed radio sources in clusters of galaxies.

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Spectral Index - Redshift Relation for Radio Galaxies and Quasars

Symposium - International Astronomical Union ◽

10.1017/s0074180900081882 ◽

1996 ◽

Vol 175 ◽

pp. 569-570

Author(s):

R.D. Dagkesamanskii

Keyword(s):

Flux Density ◽

Spectral Index ◽

Low Frequency ◽

Radio Galaxies ◽

Cosmological Evolution ◽

Radio Sources ◽

Spectral Indices ◽

Extragalactic Radio Sources

Cosmological evolution of synchrotron spectra of the powerful extragalactic radio sources was studied by many authors. Some indications of such an evolution had been found firstly by analysis of ‘spectral index - flux density’ (α – S) relation for the sample of relatively strong radio sources. Later Gopal-Krishna and Steppe extended the analysis to weaker sources and found that the slope of αmed(S) curve changes dramatically at intermediate flux densities. Gopal-Krishna and Steppe pointed out that the maxima of the αmed(S) curve and of differential source counts are at almost the same flux density ranges (see, Fig. 2). It has to be noticed that the all mentioned results were obtained using the low-frequency spectral indices and on the basis of low frequency samples.

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Bent Jets in Radio Quasars

Symposium - International Astronomical Union ◽

10.1017/s0074180900027546 ◽

1982 ◽

Vol 97 ◽

pp. 137-138

Author(s):

Susan G. Neff

Keyword(s):

Hot Spots ◽

Radio Galaxies ◽

Plasma Instability ◽

Radio Sources ◽

Central Engine ◽

Central Nozzle ◽

Quasars And Radio Galaxies

How is energy transported out from the central engine in quasars and radio galaxies to the distant radio lobes? This problem has been around since the early discovery of classical double radio sources, and is still not answered in detail. The idea of relativistic beams was first suggested by Martin Rees as a means of transporting plasma out of the nucleus (Rees, 1971, Blandford and Rees, 1974). This idea gained support first from the discovery of hot spots in the radio lobes of these large classical double sources, and later by observations of the beams themselves in radio galaxies. As more jets were observed, it became obvious that they were often curved, serpentine, or even sharply bent. This behavior has been modeled as precession of the central nozzle (Bridle et al., 1976, Ekers et al., 1978), as nuclear refraction (Henriksen et al., 1981), as a growing plasma instability (Hardee, 1981) and as various combinations of the above. At the present time, it seems safest to conclude that there are some examples of each of these processes known.

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Through the kaleidoscope: star formation the host galaxies of radio-AGN

Proceedings of the International Astronomical Union ◽

10.1017/s1743921314004177 ◽

2013 ◽

Vol 9 (S304) ◽

pp. 323-326

Author(s):

Marios Karouzos ◽

Myungshin Im ◽

Markos Trichas ◽

Tomo Goto ◽

Matt Malkan ◽

...

Keyword(s):

Star Formation ◽

Feedback Mechanism ◽

Host Galaxy ◽

Radio Sources ◽

Radio Luminosity ◽

Powerful Radio ◽

Host Galaxies ◽

Radio Jets ◽

The North ◽

Multi Wavelength

AbstractThere exist strong evidence supporting the co-evolution of central supermassive black holes and their host galaxies; however it is still under debate how such a relation comes about and whether it is relevant for all or only a subset of galaxies. A rich multi-wavelength dataset is available for the North Ecliptic Pole field, most notably surveyed by the AKARI infrared space telescope. We investigate the star-formation properties of the host galaxies of radio-AGN together with the radio feedback mechanism, potentially responsible for the eventual quenching of star formation. Using broadband SED modelling, the nuclear and host galaxy components of these sources are studied as a function of their radio luminosity. Here we present results concerning the AGN content of the radio sources in this field, while offering evidence supporting a “maintenance” type of feedback from powerful radio-jets.

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Populations of Extragalactic Radio Sources

Australian Journal of Physics ◽

10.1071/ph940625 ◽

1994 ◽

Vol 47 (5) ◽

pp. 625 ◽

Cited By ~ 19

Author(s):

JV Wall

Keyword(s):

Big Bang ◽

Current View ◽

Radio Sources ◽

Large Area ◽

Microwave Background ◽

Stellar Objects ◽

Sky Surveys ◽

Extragalactic Radio Sources ◽

The Face ◽

Quasi Stellar Objects

In the late 1950s and early 1960s, radio sky surveys were the centre of an intense and public debate-Big-Bang versus Steady-State cosmology-the arguments revolving about source counts and statistical interpretations in the face of instrumental complications. The 1965 discovery of the microwave background took the fire from the debate, but left the momentum in place for large-area radio surveys at different frequencies, and for extensive identification/redshift-measurement programs. By the 1970s the data enabled us to start disentangling the different populations of extragalactic radio sources. We could refine our taxonomy, and we could view the possibility of delineating individual cosmic histories and evolutions. We could at least describe a goal to elucidate the birth-life-death cycles of the objects involved [quasi-stellar objects (QSOs) and radio galaxies: together the 'active galactic nuclei' (AGNs)] whose unaccountably prodigious energies somehow produce the beautifully aligned radio structures with which we are now familiar. One part of John Bolton's vision to see how distorted a view of the AGN universe the original long-wavelength surveys provided. One legacy is thus the 'short-wavelength survey' for extragalactic radio sources, which has done so much to balance our picture of the radio sky. And indeed the legacy continues in the form of the immense sky surveys at present under way, complete with their sub-industries of radio-positioning and identification. From these, yet further results are emerging on spatial distribution and the skeleton structure of the universe. It is the purpose of this paper to outline something of this current view of the populations, their differences, similarities and unifying concepts.

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