Готові списки джерел за темами / NVSS radio source catalogue

Добірка наукової літератури з теми "NVSS radio source catalogue"

Автор: Grafiati

Опубліковано: 10 грудня 2022

Оновлено: 28 січня 2023

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Статті в журналах з теми "NVSS radio source catalogue"

Paronyan, Gurgen M., Hayk V. Abrahamyan, Gohar S. Harutyunyan, and Areg M. Mickaelian. "The ROSAT/NVSS AGN sample." Proceedings of the International Astronomical Union 9, S304 (October 2013): 164–65. http://dx.doi.org/10.1017/s1743921314003652.

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AbstractWe attempt to create an X-ray/radio AGN catalog and make its multiwavelength studies. ROSAT Bright Source Catalogue (BSC) contains 18,806 and ROSAT Faint Source Catalogue (FSC), 105,922 X-ray sources giving the total number of ROSAT X-ray sources 124,727 (one source is listed twice). On the other hand, NVSS radio catalogue contains 1,773,484 sources. Taking into account that X-ray sources contain AGN, bright stars and galaxies, clusters, white dwarfs (WD), cataclysmic variables (CV), etc., the cross-identification with radio catalogue may distinguish the extragalactic sources. We have cross-correlated ROSAT catalogs with NVSS one with a search radius 30 arcsec. 9,193 associations have been found. To distinguish AGN from the normal bright galaxies and clusters, Veron-Cetty & Veron AGN catalog (v.13, 2010; VCV-13) containing 168,940 objects have been used. A cross-correlation of the 9,193 ROSAT/NVSS sources with the VCV-13 with a search radius 30 arcsec resulted in 3,094 associations. Thus we are left with more 6,099 X-ray/radio sources without an optical identification. Brighter objects are normal bright galaxies, while we believe that all faint ones are candidate AGN with some contamination of distant clusters. SDSS spectroscopic survey allows us classify objects by activity types, and a number of our candidate AGN is found to be present in SDSS. We attempt to find connections between the fluxes in different wavelength ranges, which will allow us to confirm AGN and blazars candidates and in some cases find new ones.

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Andernach, H., O. V. Verkhodanov, and N. V. Verkhodanova. "Radio-optical Identification of Very-Steep Spectrum Radio Sources from the UTR-2 Catalogue." Symposium - International Astronomical Union 199 (2002): 217–18. http://dx.doi.org/10.1017/s0074180900168949.

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We used radio source catalogues accessible from the CATS database to establish radio continuum spectra for decametric radio sources in the UTR-2 catalogue. In an attempt to find further candidates for high-redshift radio galaxies, we searched the FIRST and NVSS surveys for counterparts of a sample of UTR sources with ultra-steep radio spectra (USS, α ≤ −1.2, S ∼ vα). We derived accurate positions and sizes for 23 of these USS sources. The search for optical counterparts from the APM (object) and DSS (image) databases, as well as infrared and X—ray identifications of these UTR sources are in progress.

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de Gasperin, F., H. T. Intema, and D. A. Frail. "A radio spectral index map and catalogue at 147–1400 MHz covering 80 per cent of the sky." Monthly Notices of the Royal Astronomical Society 474, no. 4 (December 5, 2017): 5008–22. http://dx.doi.org/10.1093/mnras/stx3125.

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Abstract The radio spectral index is a powerful probe for classifying cosmic radio sources and understanding the origin of the radio emission. Combining data at 147 MHz and 1.4 GHz from the TIFR GMRT Sky Survey (TGSS) and the NRAO VLA Sky Survey (NVSS), we produced a large-area radio spectral index map of ∼80 per cent of the sky (Dec. > − 40 deg), as well as a radio spectral index catalogue containing 1396 515 sources, of which 503 647 are not upper or lower limits. Almost every TGSS source has a detected counterpart, while this is true only for 36 per cent of NVSS sources. We released both the map and the catalogue to the astronomical community. The catalogue is analysed to discover systematic behaviours in the cosmic radio population. We find a differential spectral behaviour between faint and bright sources as well as between compact and extended sources. These trends are explained in terms of radio galaxy evolution. We also confirm earlier reports of an excess of steep-spectrum sources along the galactic plane. This corresponds to 86 compact and steep-spectrum source in excess compared to expectations. The properties of this excess are consistent with normal non-recycled pulsars, which may have been missed by pulsation searches due to larger than average scattering along the line of sight.

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Verkhodanov, O. V., and S. A. Trushkin. "Study of Objects of Low Radio Frequency Catalogues and IRAS Data — Cross-Identification." Symposium - International Astronomical Union 199 (2002): 221–24. http://dx.doi.org/10.1017/s0074180900168962.

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We present results of cross—identifications of the objects from two large catalogues, IRAS and the low radio frequency Texas catalogue at 365 MHz in the database CATS. The resulting list consists of 715 pairs of sources within a circle of radius of 60 arcsec. It has been cross—identified with the GB6 4.85 GHz, NVSS 1.4 GHz, FIRST 1.4 GHz, WENSS 325 MHz radio catalogues, ROSAT catalogues and different optical data lists, including APM catalogue. We selected 3 subsamples: objects matching in 3″radius, ultra steep spectrum (USS) radio sources, inverse spectrum radio sources, galactic sources. Several objects have radio spectral index α < −2, some of them in Galactic plane.

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Flesch, E. "An All-Sky Atlas of Radio/X-ray Associations." Publications of the Astronomical Society of Australia 27, no. 3 (2010): 283–89. http://dx.doi.org/10.1071/as09060.

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AbstractAn all-sky comprehensive catalogue of calculated radio and X-ray associations to optical objects is presented. Included are X-ray sources from XMM-Newton, Chandra and ROSAT catalogues, radio sources from NVSS, FIRST and SUMSS catalogues, and optical data, identifications and redshifts from the APM, USNO-A, SDSS-DR7 and the extant literature. This ‘Atlas of Radio/X-ray Associations’ inherits many techniques from the predecessor Quasars.org (2004) catalogue, but object selection is changed and processing tweaked. Optical objects presented are those which are calculated with ≥40% confidence to be associated with radio/X-ray detections, totalling 602 570 objects in all, including 23 681 double radio lobe detections. For each of these optical objects I display the calculated percentage probabilities of its being a QSO, galaxy, star, or erroneous radio/X-ray association, plus any identification from the literature. The catalogue includes 105 568 uninvestigated objects listed as 40% to >99% likely to be a QSO. The catalogue is available at http://quasars.org/arxa.htm.

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Chan, B. H. P., and L. E. Cram. "Image Processing for the Sydney University Molonglo Sky Survey (SUMSS)." Publications of the Astronomical Society of Australia 19, no. 2 (2002): 201–6. http://dx.doi.org/10.1071/as01060.

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AbstractThe Sydney University Molonglo Sky Survey (SUMSS) is a deep radio survey at 843 MHz, covering the region south of −30° declination. Designed to be a southern counterpart of the northern NRAO VLA Sky Survey (NVSS), SUMSS is over 40% complete, and it is now time to devise ways to generate the source catalogue for the survey. We describe here new methods to deal with image artifacts to minimise spurious fits by automatic source fitting algorithms. With the new techniques, an automatically generated, objective catalogue can be made to a 10 mJy cutoff. Catalogues can be made to a 5 mJy cutoff provided that special care is taken and certain artifacts are avoided.

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Żywucka, Natalia, Dorota Koziel-Wierzbowska, and Arti Goyal. "Catalogue with visual morphological classification of 32,616 radio galaxies with optical hosts." Proceedings of the International Astronomical Union 15, S356 (October 2019): 361–63. http://dx.doi.org/10.1017/s174392132000335x.

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AbstractWe present the catalogue of Radio sources associated with Optical Galaxies and having Unresolved or Extended morphologies I (ROGUE I). It was generated by cross-matching galaxies from the Sloan Digital Sky Survey Data Release 7 (SDSS DR 7) as well as radio sources from the First Images of Radio Sky at Twenty Centimetre (FIRST) and the National Radio Astronomical Observatory VLA Sky Survey (NVSS) catalogues. We created the largest handmade catalogue of visually classified radio objects and associated with them optical host galaxies, containing 32,616 galaxies with a FIRST core within 3 arcsec of the optical position. All listed objects possess the good quality SDSS DR 7 spectra with the signal-to-noise ratio > 10 and spectroscopic redshifts up to z = 0.6. The radio morphology classification was performed by a visual examination of the FIRST and the NVSS contour maps overlaid on a DSS image, while an optical morphology classification was based on the 120 arcsec snapshot images from SDSS DR 7.The majority of radio galaxies in ROGUE I, i.e. ∼ 93%, are unresolved (compact or elongated), while the rest of them exhibit extended morphologies, such as Fanaroff-Riley (FR) type I, II, and hybrid, wide-angle tail, narrow-angle tail, head-tail sources, and sources with intermittent or reoriented jet activity, i.e. double–double, X–shaped, and Z–shaped. Most of FR IIs have low radio luminosities, comparable to the luminosities of FR Is. Moreover, due to visual check of all radio maps and optical images, we were able to discover or reclassify a number of radio objects as giant, double–double, X–shaped, and Z–shaped radio galaxies. The presented sample can serve as a database for training automatic methods of identification and classification of optical and radio galaxies.

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Siewert, Thilo M., Matthias Schmidt-Rubart, and Dominik J. Schwarz. "Cosmic radio dipole: Estimators and frequency dependence." Astronomy & Astrophysics 653 (September 2021): A9. http://dx.doi.org/10.1051/0004-6361/202039840.

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The cosmic radio dipole is of fundamental interest to studies of cosmology. Recent works have put forth open questions about the nature of the observed cosmic radio dipole. In the current work, we use simulated source count maps to test a linear and a quadratic estimator for possible biases in the estimated dipole amplitude with respect to the masking procedure. We find a superiority on the part of the quadratic estimator, which we used to analyse the TGSS-ADR1, WENSS, SUMSS, and NVSS radio source catalogues, spread over a decade of frequencies. We applied the same masking strategy to all four surveys to produce comparable results. In order to address the differences in the observed dipole amplitudes, we cross-matched the two surveys located at both ends of the analysed frequency range. For the linear estimator, we identified a general bias in the estimated dipole directions. The positional offsets of the quadratic estimator to the cosmic microwave background (CMB) dipole for skies with 107 simulated sources is found to be below one degree and the absolute accuracy of the estimated dipole amplitudes is better than 10−3. For the four radio source catalogues, we find an increasing dipole amplitude with decreasing frequency, which is consistent with results from the literature and the results of the cross-matched catalogue. We conclude that for all analysed surveys, the observed cosmic radio dipole amplitudes exceed the expectations derived from the CMB dipole, which cannot strictly be explained by a kinematic dipole alone.

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Et al., Rashed. "Studying the Flux Density of Bright Active Galaxies at Different Spectral Bands." Baghdad Science Journal 16, no. 1 (March 17, 2019): 0230. http://dx.doi.org/10.21123/bsj.16.1.(suppl.).0230.

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Statistical studies are reported in this article for an active galactic nuclei sample of different type of active galaxies Seyferts 1, Seyferts 2, and Quasars. These sources have been selected from a Catalogue for bright X-ray galaxies. The name of this index is ROSAT Bright Source Catalogue (RBSC) and the NRAO VLA Sky Survey (NVSS). In this research, multi-wavelength observational bands Radio at 1.4 GHz, Optical at 4400 A0, and X-ray at energy 0.1-2.4 KeV have been adopted in this study. The behavior of flux density ratios has been studied , with respect to the absolute magnitude . Furthermore, the Seyfert1 and Seyfert 2 objects are combined in one group and the QSOs are collectest in another group. Also, it has been found that the ratios , are increasing towards fainter optical absolute magnitude especially in Quasars.

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Et al., Rashed. "Studying the Flux Density of Bright Active Galaxies at Different Spectral Bands." Baghdad Science Journal 16, no. 1(Suppl.) (March 17, 2019): 0230. http://dx.doi.org/10.21123/bsj.2019.16.1(suppl.).0230.

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Більше джерел

Тези доповідей конференцій з теми "NVSS radio source catalogue"

Bursov, N., S. Trushkin, A. Kudryashova, P. Tsybulev, A. Borisov, M. Khabibullina, and D. Kuandykova. "Sources of the survey on the declination of microquasar GRS 1915+105." In ASTRONOMY AT THE EPOCH OF MULTIMESSENGER STUDIES. Proceedings of the VAK-2021 conference, Aug 23–28, 2021. Crossref, 2022. http://dx.doi.org/10.51194/vak2021.2022.1.1.141.

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Анотація:

With the RATAN-600 radio telescope, we have detected about 1300 radio sources at 4.7 GHz frequency, identiﬁed withsources from other catalogs, mostly from the NVSS catalog at 1.4 GHz. From 6 June 2020 to 28 May 2021, the strip (width∼ 35 ′ ) of the sky on the microquasar GRS 1915+105 declination (Dec = +11 ◦ 56 ′ 44 ′′ ) was observed with a four-beamcomplex of four-channel sensitive radiometers, established in the focal line of the ’Western sector’ antenna of the RATAN-600. We summarized the data received in narrow channels to obtain maximum sensitivity of the ﬂux (∼ 3 mJy/beam) inthe 600 MHz frequency band at the center 4.7 GHz frequency. This value is constrained only by the eﬀect of confusion foran antenna beam with dimensions about 1 ′ × 35 ′ . We obtained about 20–25 high-quality day records divided by hours everymonth and 12 average hour drift scans for a year. We plotted and analyzed the light curves for bright variable sources forall 365 days. We identiﬁed the detected sources with the objects from the CATS database to plot compiled radio spectra ofthe sources. Most sources were identiﬁed as galaxies and quasars. Some supernova remnants were detected in cross-sectionsof the Galactic plane.

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Lykou, F. "Correlation of DARWIN mission star catalogue with radio source surveys." In RECENT ADVANCES IN ASTRONOMY AND ASTROPHYSICS: 7th International Conference of the Hellenic Astronomical Society. AIP, 2006. http://dx.doi.org/10.1063/1.2348008.

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