- ID:
- ivo://nasa.heasarc/gpa
- Title:
- First Galactic Plane Survey at 8.35 and 14.35 GHz
- Short Name:
- GP8.35/14.35
- Date:
- 07 Mar 2025
- Publisher:
- NASA/GSFC HEASARC
- Description:
- This table contains results from the first Galactic Plane (GP) Survey at 8.35 and 14.35 GHz (3.6 and 2.1 cm). In this project, the first images of the GP in the galactic latitude range |b| < 5 degrees and the galactic longitude range -15 degrees < l < 255 degrees at 8.35 and 14.35 GHz were presented. These observations used the National Radio Astronomy Observatory-NASA Green Bank Earth Station to survey the sky simultaneously at these two frequencies. These GPA data are the first results from the GP Survey observations, a program to monitor this portion of the sky at 8.35 and 14.35 GHz. The GP Survey series is intended to detect short-lived radio sources. In their published paper, the authors presented four independent observations of the Galactic plane, combined to provide a set of reference images of the Galactic plane. This first GPA survey covers 0.82 steradian (6.5%) of the sky. This table conatins a source list of all sources which were brighter than 0.9 Jy at 8.35 GHz and also of all sources brighter than 2.5 Jy at 14.35 GHz. The FITS format images, residual images, source lists, and archive data are available over the internet at <a href="http://www.gb.nrao.edu/~glangsto/GPA">http://www.gb.nrao.edu/~glangsto/GPA</a> . This table was created by the HEASARC in December 2004 based on <a href="https://cdsarc.cds.unistra.fr/ftp/cats/J/AJ/119/2801/">CDS catalog J/AJ/119/2801/</a>, tables s8.dat and s14.dat. This is a service provided by NASA HEASARC .
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- ID:
- ivo://nasa.heasarc/gleamegcat
- Title:
- GaLactic and Extragalactic All-sky MWA Survey (GLEAM) Extragalactic Catalog
- Short Name:
- GLEAMEGCAT
- Date:
- 07 Mar 2025
- Publisher:
- NASA/GSFC HEASARC
- Description:
- Using the Murchison Widefield Array (MWA), the low-frequency Square Kilometre Array (SKA1 LOW) precursor located in Western Australia, the authors have completed the GaLactic and Extragalactic All-sky MWA (GLEAM) survey, and present the resulting extragalactic catalog, utilizing the first year of observations. The catalog covers 24,402 square degrees, over Declinations south of +30 degrees and Galactic latitudes outside 10 degrees of the Galactic Plane, excluding some areas such as the Magellanic Clouds. It contains 307,455 radio sources with 20 separate flux density measurements across 72 - 231 MHz, selected from a time- and frequency-integrated image centered at 200 MHz, with a resolution of ~ 2 arcminutes. Over the catalogued region, the authors estimate that the catalog is 90% complete at 170 mJy, and 50% complete at 55 mJy, and large areas are complete at even lower flux density levels. Its reliability is 99.97% above the 5-sigma detection threshold, which itself is typically 50 mJy. These observations constitute the widest fractional bandwidth and largest sky area survey at radio frequencies to date, and calibrate the low frequency flux density scale of the southern sky to better than 10%. The reference paper presents details of the flagging, imaging, mosaicking, and source extraction/characterization, as well as estimates of the completeness and reliability. All source measurements and images are available online at <a href="http://www.mwatelescope.org/">http://www.mwatelescope.org/</a>. This is the first in a series of publications describing the GLEAM survey results. GLEAM observes in week-long drift scan campaigns, with a single Dec strip observed each night. The observing bandwidth of 72-231 MHz is covered by shifting frequencies by 30.72 MHz every two minutes, avoiding the Orbcomm satellite constellation at 134-139 MHz. Thus, the frequencies of observation are 72-103, 103-134, 139-170, 170-200. and 200-231 MHz. These may be further subdivided for imaging purposes; in this study, the 30.72 MHz bandwidth is commonly subdivided into four 7.68 MHz sub-channels. The native channel resolution of these observations is 40 kHz and the native time resolution is 0.5 seconds. This paper concerns only data collected in the first year, i.e. four weeks between June 2013 and July 2014. The authors also do not image every observation, since the survey is redundant across approximately 50% of the observed RA ranges, and some parts are adversely acted by the Galactic plane and Centaurus A. Table 1 in the reference paper lists the observations which have been used to create this first GLEAM catalog. The HEASARC has converted the flux density units from those given in the original table (Jy and Jy/beam) to its standard units for radio flux densities (mJy and mJy/beam). This table was originally ingest by the HEASARC in February 2017 based on <a href="https://cdsarc.cds.unistra.fr/ftp/cats/VIII/100">CDS Catalog VIII/100</a> file gleamegc.dat, the GLEAM Extragalactic Catalog. It was updated in May 2018 to the corrected version provided to the CDS by the author. This is a service provided by NASA HEASARC .
- ID:
- ivo://nasa.heasarc/gcps
- Title:
- Galactic Center P-Band (330 MHz) Survey
- Short Name:
- GCPS
- Date:
- 07 Mar 2025
- Publisher:
- NASA/GSFC HEASARC
- Description:
- The Galactic Center P-Band (330 MHz) Survey (GCPS) is based on wide-field, subarcminute-resolution Very Large Array (VLA) imagery of the Galactic center region at 330 MHz. With a resolution of ~7"x12" and an rms noise of 1.6 mJy/beam, this image represented a significant increase in resolution and sensitivity over the previously published VLA image at this frequency. The improved sensitivity more than tripled the census of small-diameter sources in the region, resulted in the detection of two new nonthermal filaments (NTFs), 18 NTF candidates, and 30 pulsar candidates, revealed previously known extended sources in greater detail, and has resulted in the first detection of Sagittarius A* in this frequency range. Two sets of observations were obtained. The first was conducted at 330 MHz in the A configuration of the VLA in 1996 October. The second set of P-band observations were obtained in the A and B configurations of the VLA between 1998 March and 1999 May. This Browse table was created by the HEASARC in May 2005 based on the <a href="https://cdsarc.cds.unistra.fr/ftp/cats/J/AJ/128/1646">CDS Catalog J/AJ/128/1646</a>, tables table2.dat and table3.dat. This is a service provided by NASA HEASARC .
- ID:
- ivo://nasa.heasarc/gmrtas150m
- Title:
- Giant Metrewave Radio Telescope All-Sky 150-MHz Radio Source Catalog
- Short Name:
- GMRTAS150M
- Date:
- 07 Mar 2025
- Publisher:
- NASA/GSFC HEASARC
- Description:
- This table contains results from the first full release of a survey of the 150-MHz radio sky, observed with the Giant Metrewave Radio Telescope (GMRT) between April 2010 and March 2012 as part of the TIFR GMRT Sky Survey (TGSS) project. Aimed at producing a reliable compact source survey, the authors' automated data-reduction pipeline efficiently processed more than 2000 hours of observations with minimal human interaction. Through application of innovative techniques such as image-based flagging, direction-dependent calibration of ionospheric phase errors, correcting for systematic offsets in antenna pointing, and improving the primary beam model, the authors created good quality images for over 95% of the 5,336 pointings. This data release covers 36,900 deg<sup>2</sup> (or 3.6 pi steradians) of the sky between -53 and +90 degrees Declination, which is 90% of the total sky. The majority of pointing images has a noise level below 5 mJy/beam (the median RMS background noise is 3.5 mJy per beam), with an approximate resolution of 25" x 25" (or 25" x 25"/cos(Dec-19<sup>o</sup>) for pointings south of 19 degrees Declination). The authors have produced a catalog of 0.62 Million radio sources with flux densities ranging from 11.1 mJy to 9.22 kJy that are derived from an initial, high-reliability source extraction at the 7-sigma level. For the bulk of the survey, the measured overall astrometric accuracy is better than 2 arcseconds in Right Ascension and Declination, while the flux density accuracy is estimated at approximately 10%. Within the scope of the TGSS Alternative Data Release (TGSS ADR) project, the source catalog, as well as 5,336 mosaic images (5 x 5 degree<sup>2</sup>) and an image cutout service, are made publicly available as a service to the astronomical community. (The TGSS images and cutout server are available through the project website at <a href="http://tgssadr.strw.leidenuniv.nl/">http://tgssadr.strw.leidenuniv.nl/</a>). In addition to enabling a wide range of different scientific investigations, the authors anticipate that these survey products will provide a solid reference for various new low-frequency radio aperture array telescopes (LOFAR, LWA, MWA, SKA-low), and can play an important role in characterizing the epoch-of-reionization (EoR) foreground. The TGSS ADR project aims at continuously improving the quality of the survey data products. Near-future improvements include replacement of bright source snapshot images with archival targeted observations, using new observations to fill the holes in sky coverage and to replace very poor quality observational data, and an improved flux calibration strategy for less severely affected observational data. This table was created by the HEASARC in February 2017 based on <a href="https://cdsarc.cds.unistra.fr/ftp/cats/J/A+A/598/A78">CDS Catalog J/A+A/598/A78</a> file table3.dat. This is a service provided by NASA HEASARC .
- ID:
- ivo://nasa.heasarc/gmrtelain2
- Title:
- Giant Metrewave Radio Telescope ELAIS-N2 Field 610-MHz Radio Source Catalog
- Short Name:
- GMRTELAIN2
- Date:
- 07 Mar 2025
- Publisher:
- NASA/GSFC HEASARC
- Description:
- This table contains a source catalog based on observations of the European Large-Area ISO Survey-North 2 (ELAIS-N2) field taken at 610 MHz with the Giant Metrewave Radio Telescope (GMRT). Thirteen pointings were observed, covering a total area of ~ 6 square degrees with a resolution of 6.5 x 5 arcsec<sup>2</sup>, position angle of +70 degrees. The rms noise at the center of the pointings is typically ~ 85 microJansky (µJy) before correction for the GMRT primary beam . The techniques used for data reduction and production of a mosaicked image of the region are described in the reference paper, where the final mosaic, along with a catalog of 1310 sources detected above a 6-sigma threshold, are presented. The survey complements existing radio and infrared data that are available for this region. For further details of the surveys and data analysis procedures, please refer to the published paper. This table contains the ELAIS-N2 catalog of 1310 detected 610-MHz radio sources. This table was created by the HEASARC in February 2012 based the source catalog of the Cambridge GMRT Survey of the ELAIS-N2 region which was obtained from the University of Cambridge Astrophysics Group Surveys and Catalogs website at <a href="http://www.mrao.cam.ac.uk/facilities/surveys/gmrt/elais-n2/">http://www.mrao.cam.ac.uk/facilities/surveys/gmrt/elais-n2/</a> file GMRT_EN2_dr1.dat. This is a service provided by NASA HEASARC .
- ID:
- ivo://nasa.heasarc/gmrtelain1
- Title:
- Giant Metrewave Radio Telescope ELAIS-N1 Field 610-MHz Radio Source Catalog
- Short Name:
- GMRTELAIN1
- Date:
- 07 Mar 2025
- Publisher:
- NASA/GSFC HEASARC
- Description:
- This table contains a source catalog based on observations of the European Large-Area ISO Survey-North 1 (ELAIS-N1) field taken at 610 MHz with the Giant Metrewave Radio Telescope. Nineteen pointings were observed, covering a total area of ~ 9 square degrees with a resolution of 6 x 5 arcsec<sup>2</sup>, position angle of +45 degrees. Four of the pointings were deep observations with an rms of ~ 40 microJansky (µJy) before primary beam correction, with the remaining fifteen pointings having an rms of ~ 70 uJy. The techniques used for data reduction and production of a mosaicked image of the region are described in the reference paper, where the final mosaic, along with a catalog of 2500 sources detected above a 6-sigma threshold, are presented. This work complements the large amount of optical and infrared data already available on the region. In their paper, the authors calculate 610-MHz source counts down to 270 uJy, and find further evidence for the turnover in differential number counts below 1 mJy, previously seen at both 610 MHz and 1.4 GHz. For further details of the surveys and data analysis procedures, please refer to the published paper. This table contains the ELAIS-N1 catalog of 2500 detected 610-MHz radio sources. This table was created by the HEASARC in February 2012 based on <a href="https://cdsarc.cds.unistra.fr/ftp/cats/J/MNRAS/383/75">CDS Catalog J/MNRAS/383/75</a> file catalog.dat. This is a service provided by NASA HEASARC .
- ID:
- ivo://nasa.heasarc/gmrt4f150m
- Title:
- Giant Metrewave Radio Telescope Field I 150-MHz Radio Source Catalog
- Short Name:
- GMRT4F150M
- Date:
- 07 Mar 2025
- Publisher:
- NASA/GSFC HEASARC
- Description:
- Foreground removal is a major challenge for detecting the redshifted 21-cm neutral hydrogen (HI) signal from the Epoch of Reionization. The authors have used 150-MHz Giant Metrewave Radio Telescope (GMRT) observations to characterize the statistical properties of the foregrounds in four different fields of view. The observational data were used to assess point source subtraction. Considering the brightest source (~1 Jy) in each field, the authors find that the residual artefacts are less than 1.5% in the most sensitive field (FIELD I). Considering all the sources in the fields, they find that the bulk of the image is free of artefacts, the artefacts being localized to the vicinity of the brightest sources. The authors have used FIELD I, which has an rms noise of 1.3 mJy beam<sup>-1</sup>, to study the properties of the radio source population to a limiting flux of 9 mJy. The differential source count is well fitted with a single power law of slope -1.6. They find there is no evidence for flattening of the source counts towards lower flux densities which suggests that source population is dominated by the classical radio-loud active galactic nuclei. The authors have observed FIELD I in GMRT Time Allocation Committee (GTAC) cycle 15 in 2008 January, whereas FIELD II and FIELD III were observed in cycle 17 during 2010 February. These target fields were selected at high Galactic latitudes (b > 10<sup>o</sup>) which were up at night time during the GTAC cycles 15 and 17, and which contain relatively few bright sources (>= 0.3 Jy) in the 1400 MHz NRAO VLA Sky Survey (NVSS). Finally, FIELD IV was observed in cycle 8 (2005 June). Full details of these 4 observations are given in Table 1 of the reference paper. This table contains the 150-MHz source catalog for the most sensitive observation, namely the 9.8-hour observation of Field I (centered on J2000.0 RA and Dec of 5<sup>h</sup> 30<sup>m</sup> 00<sup>s</sup>, +60<sup>o</sup> 00' 00"), which was made on 2008 January 8. This table was created by the HEASARC in September 2013 based on <a href="https://cdsarc.cds.unistra.fr/ftp/cats/J/MNRAS/426/3295">CDS Catalog J/MNRAS/426/3295</a> file tablea1.dat This is a service provided by NASA HEASARC .
- ID:
- ivo://nasa.heasarc/gmrtha325m
- Title:
- Giant Metrewave Radio Telescope Herschel-ATLAS/GAMA Flds 325-MHz Source Catalog
- Short Name:
- GMRTHA325M
- Date:
- 07 Mar 2025
- Publisher:
- NASA/GSFC HEASARC
- Description:
- This table contains a source list from a 325-MHz survey undertaken with the Giant Metrewave Radio Telescope (GMRT). This survey covers a large part of the three equatorial fields at 9, 12 and 14.5 h of Right Ascension from the Herschel-Astrophysical Terahertz Large Area Survey (H-ATLAS) in the area also covered by the Galaxy And Mass Assembly (GAMA) survey. The full data set, after some observed pointings were removed during the data reduction process, comprises 212 GMRT pointings covering ~90 deg<sup>2</sup> of sky. A list of the central coordinates of the images from which the sources listed in this catalog are derived is available at <a href="http://gmrt-gama.extragalactic.info/GMRT_GAMA_IMAGE_CENTERS">http://gmrt-gama.extragalactic.info/GMRT_GAMA_IMAGE_CENTERS</a>. The images themselves are available at <a href="http://gmrt-gama.extragalactic.info/">http://gmrt-gama.extragalactic.info/</a>. The authors have imaged and catalogued the data using a pipeline that automates the process of flagging, calibration, self-calibration and source detection for each of the survey pointings. The resulting images have resolutions of between 14 and 24 arcseconds and minimum rms noise (away from bright sources) of ~1 mJy beam<sup>-1</sup>, and the catalogue contains 5263 sources brighter than the local 5 sigma values. In the reference paper, the authors investigate the spectral indices of those GMRT sources which are also detected at 1.4 GHz and find them to agree broadly with previously published results; there is no evidence for any flattening of the radio spectral index below S<sub>1.4</sub> = 10 mJy. This work adds to the large amount of available optical and infrared data in the H-ATLAS equatorial fields and will facilitate further study of the low-frequency radio properties of star formation and AGN activity in galaxies out to z ~1. This table was created by the HEASARC in December 2013 based on electronic versions of the 3 catalogs that comprise Table 3 from the reference paper which were obtained from the MNRAS web site. Some of the values for the name parameter in the HEASARC's implementation of this table were corrected in April 2018. This is a service provided by NASA HEASARC .
- ID:
- ivo://nasa.heasarc/gmrt1hxcsf
- Title:
- Giant Metrewave Radio Telescope 1h XMM/Chandra Survey Fld 610-MHz Source Catalog
- Short Name:
- GMRT1HXCSF
- Date:
- 07 Mar 2025
- Publisher:
- NASA/GSFC HEASARC
- Description:
- This table contains the results of a deep 610-MHz survey of the 1<sup>hr</sup> XMM-Newton/Chandra survey area with the Giant Metre-wave Radio Telescope (GMRT). The resulting maps have a resolution of ~7 arcseconds and an rms noise limit of 60 µJy (µJy). To a 5-sigma detection limit of 300 uJy, the authors detect 223 sources within a survey area of 64 arcminutes in diameter. They compute the 610-MHz source counts and compare them to those measured at other radio wavelengths. The well-known flattening of the Eucidean-normalized 1.4-GHz source counts below ~ 2 mJy, usually explained by a population of starburst galaxies undergoing luminosity evolution, is seen at 610 MHz. In 2004 August, the 1<sup>hr</sup> field (centered at (J2000.0) RA, Dec = 01<sup>h</sup> 45<sup>m</sup> 27<sup>s</sup>, -04<sup>o</sup> 34' 42") was observed for approximately 4.5 hours at 610 MHz with the GMRT. Observations were carried out in dual band, spectral line mode, the former to maximize bandwidth and the latter to minimize chromatic aberration. Two sidebands, each of 128 spectral channels of 125 kHz, were centred on 602 and 618 MHz to give a total of 32 MHz bandwidth, with two independent circular polarizations recorded. Sources were extracted with the AIPS task SAD. A conservative peak flux density detection limit of 5 sigma (i.e. 300 uJy) was used to minimize the number of noise spikes spuriously detected as sources. In the areas surrounding the five brightest sources, detection was performed separately with higher detection thresholds to account for the higher rms noise. Within the 20% power radius of the GMRT primary beam at 610 MHz (32 arcminutes), 213 sources were discovered above a 5-sigma peak flux density detection limit of 300 uJy. In order to determine the success of the SAD source extraction, both the science images and the residual noise maps were carefully inspected. There were eight extended sources where the Gaussian model fit by SAD inadequately described the data: these are marked by source_flag = 'a' in this table. The characteristics of these sources were determined using the AIPS task TVSTAT, and contour plots of them are shown in Fig. 1 of the reference paper. Five of these appear to contain two peaks joined by extended emission, that is, they are double-lobe sources. This table was created by the HEASARC in June 2012 based on <a href="https://cdsarc.cds.unistra.fr/ftp/cats/J/MNRAS/378/995">CDS Catalog J/MNRAS/378/995</a> file table1.dat. This is a service provided by NASA HEASARC .
- ID:
- ivo://nasa.heasarc/gmrtj0916
- Title:
- Giant Metrewave Radio Telescope J0916+6348 Field Radio Source Catalog
- Short Name:
- GMRTJ0916
- Date:
- 07 Mar 2025
- Publisher:
- NASA/GSFC HEASARC
- Description:
- This table contains a catalog based on deep multifrequency observations made using the Giant Metrewave Radio Telescope (GMRT) at 153, 244, 610 and 1260 MHz of a field centred on J0916+6348, to search for evidence of fossil radio lobes which could be due to an earlier cycle of episodic activity of the parent galaxy, as well as haloes and relics in clusters of galaxies. The authors do not find any unambiguous evidence of episodic activity in a list of 374 sources, suggesting that such activity is rare even in relatively deep low-frequency observations. The authors examine the spectra of all the sources by combining their observations with those from the Westerbork Northern Sky Survey (WENSS), NRAO (National Radio Astronomy Observatories) VLA (Very Large Array) Sky Survey (NVSS) and the Faint Images of the Radio Sky at Twenty-Centimeters Survey (FIRST). Considering only those which have measurements at a minimum of 3 different frequencies, they find that almost all sources are consistent with a straight spectrum with a median spectral index alpha ~ 0.8 (S<sub>nu</sub> ~ nu<sup>-alpha</sup>) which appears steeper than theoretical expectations of the injection spectral index. The authors identify 14 very-steep-spectrum sources with alpha >~ 1.3. This table contains the list of 317 sources (out of the 374 sources which were within 1.5 degrees of the phase center at 153 MHz and had peak brightnesses at least 6 times larger than the local rms value) which were detected at a minimum of 3 frequencies out of the 6 frequencies (153, 244, 327, 610, 1260 and 1400 MHz) which were utilized in this study. The new observations were made on 2005 December 12 at 153 MHz, 2005 November 26 at 244 MHz and 610 MHz, and on 2008 April 22 at 1260 MHz, on the Giant Metrewave Radio Telescope (Pune, India). This table was created by the HEASARC in March 2012 based on <a href="https://cdsarc.cds.unistra.fr/ftp/cats/J/MNRAS/392/1403">CDS Catalog J/MNRAS/392/1403</a> file table2.dat. This is a service provided by NASA HEASARC .
