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VLA Lockman Hole 1400-MHz Radio Source Catalog

Metadata Updated: September 19, 2025

In the run-up to routine observations with the upcoming generation of radio facilities, the nature of the sub-mJy radio population has been hotly debated. In this paper, the authors describe multi-frequency data designed to probe the emission mechanism that dominates in these faint radio sources. Their analysis is based on observations of the Lockman Hole (LH) using the Giant Metrewave Radio Telescope (GMRT) near Pune, India - the deepest 610-MHz imaging yet reported - together with 1.4-GHz imaging from the Very Large Array (VLA), which are well matched in resolution and sensitivity to the GMRT data: sigma<sub>610MHz</sub> ~ 15 µJy/beam (µJy/beam), sigma}<sub>1.4GHz</sub> ~ 6 µJy/beam, and full width at half-maximum (FWHM) ~ 5 arcseconds. The GMRT and VLA data are cross-matched to obtain the radio spectral indices for the faint radio emitters. During six 12-hr sessions in 2006 February and July, the authors obtained data at 610 MHz for three pointings (FWHM ~ 43 arcminutes) in the LH (see Table 1 of the reference paper for full details), separated by 11 arcminutes (the LOCKMAN-E, LOCK-3 and LHEX-4 fields), typically with 28 of the 30 antennas that comprise the GMRT. The total integration time in each field, after overheads, was 16 hr. The final image had a noise level in the central 100 arcmin<sup>2</sup> of 14.7 µJy/beam, the deepest map reported at 610 MHz as of the date of publication, despite the modest integration time. New and archival data were obtained at the same three positions using the National Radio Astronomy Observatory's VLA, largely in its B configuration. This table contains 1450 sources found in the LH field at 1400 MHz by the VLA. For 17 of the sources which have multiple components, the 29 individual components are listed as well. Thus, the final table contains 1479 (1450 + 29) entries. Source extraction was based on criteria of peak brightness > 5 times the local rms and integrated flux density > 3 times the local rms. This table was created by the HEASARC in February 2012 based on <a href="https://cdsarc.cds.unistra.fr/ftp/cats/J/MNRAS/397/281">CDS Catalog J/MNRAS/397/281</a> file table4.dat. This is a service provided by NASA HEASARC .

Access & Use Information

Public: This dataset is intended for public access and use. License: No license information was provided. If this work was prepared by an officer or employee of the United States government as part of that person's official duties it is considered a U.S. Government Work.

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Dates

Metadata Created Date April 11, 2025
Metadata Updated Date September 19, 2025

Metadata Source

Harvested from NASA Data.json

Additional Metadata

Resource Type Dataset
Metadata Created Date April 11, 2025
Metadata Updated Date September 19, 2025
Publisher High Energy Astrophysics Science Archive Research Center
Maintainer
Identifier ivo://nasa.heasarc/vlalh1400m
Data Last Modified 2025-09-10
Category Astrophysics
Public Access Level public
Bureau Code 026:00
Metadata Context https://project-open-data.cio.gov/v1.1/schema/catalog.jsonld
Schema Version https://project-open-data.cio.gov/v1.1/schema
Catalog Describedby https://project-open-data.cio.gov/v1.1/schema/catalog.json
Harvest Object Id 5007ab2e-6c0a-4d5b-8ad8-d84fc4d20b8f
Harvest Source Id 58f92550-7a01-4f00-b1b2-8dc953bd598f
Harvest Source Title NASA Data.json
Homepage URL https://heasarc.gsfc.nasa.gov/W3Browse/all/vlalh1400m.html
Program Code 026:000
Source Datajson Identifier True
Source Hash cdb44b398ff2d37ec83840513d1932241eaa9e62447a2b2227824663e83e18b8
Source Schema Version 1.1

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