Information on Service 'LoTSS-DR2 Source catalog cone search'

Further access options are discussed below

In this data release from the ongoing LOw-Frequency ARray (LOFAR) Two-metre Sky Survey (LoTSS) we present 120-168 MHz images covering 27% of the northern sky. Our coverage is split into two regions centred at approximately 12h45m +44°30′ and 1h00m +28°00′ and spanning 4178 and 1457 square degrees respectively. The images were derived from 3,451 hrs (7.6 PB) of LOFAR High Band Antenna data which were corrected for the direction-independent instrumental properties as well as direction-dependent ionospheric distortions during extensive, but fully automated, data processing. A catalogue of 4,395,448 radio sources is derived from our total intensity (Stokes I) maps, where the majority of these have never been detected at radio wavelengths before. At 6′′ resolution, our full bandwidth Stokes I continuum maps with a central frequency of 144 MHz have: a median rms sensitivity of 83 μ Jy/beam; a flux density scale accuracy of approximately 10%; an astrometric accuracy of 0.2′′; and we estimate the point-source completeness to be 90% at a peak brightness of 0.8 mJy/beam. By creating three 16 MHz bandwidth images across the band we are able to measure the in-band spectral index of many sources, albeit the error on the derived spectral index is > ±0.2 which is a consequence of our flux-density scale accuracy and small fractional bandwidth. Our circular polarisation (Stokes V) 20′′ resolution 120-168 MHz continuum images have a median rms sensitivity of 95 μ Jy/beam, and we estimate a Stokes I to Stokes V leakage of 0.056%. Our linear polarisation (Stokes Q and Stokes U) image cubes consist of 480 97.6 kHz wide planes and have a median rms sensitivity per plane of 10.8mJy/beam at 4′ and 2.2mJy/beam at 20′′; we estimate the Stokes I to Stokes Q/U leakage to be approximately 0.2%. Here we characterise and publicly release our Stokes I, Q, U and V images in addition to the calibrated uv-data to facilitate the thorough scientific exploitation of this unique dataset. This service queries the Stokes I continuum mosaic source catalogue.

For a list of all services and tables belonging to this service's resource, see Information on resource 'lotss_dr2/q'

Overview

You can access this service using:

static -- static (i.e. prepared) data or custom client-side code; probably used to access ancillary files here
form -- allows access via an HTML form
scs.xml -- a standard SCS interface as defined by the IVOA to access catalog-type data; SCS clients use https://vo.astron.nl/lotss_dr2/q/src_cone/scs.xml? to access the service

This service is published as follows:

Within the set(s) local with the renderer form
Within the set(s) ivo_managed with the renderer scs.xml
Within the set(s) ivo_managed with the renderer tap

local means it is listed on our front page, ivo_managed means it has a record in the VO registry.

Other services provided on the underlying data include:

Spatial Coverage

Input Fields

The following fields are available to provide input to the service (with some renderers, some of these fields may be unavailable):

Name	Table Head	Description	Unit	UCD
DEC	Delta (ICRS)	Declination (ICRS decimal)	deg	pos.eq.dec
hscs_pos	Position/Name	Coordinates (as h m s, d m s or decimal degrees), or SIMBAD-resolvable object	N/A	N/A
hscs_sr	Search radius	Search radius in arcminutes	N/A	N/A
MAXREC	Match limit	Maximum number of records returned. Pass 0 to retrieve service parameters.	N/A	N/A
RA	Alpha (ICRS)	Right Ascension (ICRS decimal)	deg	pos.eq.ra
RESPONSEFORMAT	Output Format	File format requested for output.	N/A	meta.code.mime
SR	Search Radius	Search radius	deg	N/A
VERB	Verbosity	Exhaustiveness of column selection. VERB=1 only returns the most important columns, VERB=2 selects the columns deemed useful to the average user, VERB=3 returns a table with all available columns.	N/A	N/A

Default Output Fields

The following fields are contained in the output by default. More fields may be available for selection; these would be given below in the VOTable output fields.

Name	Table Head	Description	Unit	UCD
DC_Maj	DC_Maj	The FWHM of the major axis of the source, after de-convolution with the 6-arcsec LOFAR beam	arcsec	phys.angsize
DC_Min	DC_Min	The FWHM of the minor axis of the source, after de-convolution with the 6-arcsec LOFAR beam	arcsec	phys.angsize
DC_PA	DC_PA	The position angle of the major axis of the source measured east of north, after de-convolution with the 6-arcsec LOFAR beam	deg	pos.posang
DEC	Dec	Position from PyBDSF or combination of PyBDSF components	deg	pos.eq.dec;meta.main
E_DC_Maj	E_DC_Maj	The 1-sigma error on the FWHM of the deconvolved major axis of the source	arcsec	stat.error;phys.angsize
E_DC_Min	E_DC_Min	The 1-sigma error on the FWHM of the deconvolved minor axis of the source	arcsec	stat.error;phys.angsize
E_DC_PA	E_DC_PA	The 1-sigma error on the position angle of the deconvolved major axis of the source	deg	stat.error;pos.posang
E_DEC	error Dec	Estimated by PyBDSF. Only fitting uncertainties are included	arcsec	stat.error;pos.eq.dec
E_Maj	E_Maj	The 1-sigma error on the FWHM of the major axis of the source	arcsec	stat.error;phys.angsize
E_Min	E_Min	The 1-sigma error on the FWHM of the minor axis of the source	arcsec	stat.error;phys.angsize
E_PA	E_PA	The 1-sigma error on the position angle of the major axis of the source	deg	stat.error;pos.posang
E_Peak_flux	error Peak flux	The 1-sigma error on the peak flux density per beam of the source	mJy/beam	stat.error;phot.flux.density;em.radio
E_RA	error RA	Estimated by PyBDSF. Only fitting uncertainties are included	arcsec	stat.error;pos.eq.ra
E_Total_flux	error Total flux	The 1-sigma on the total flux density of the source	mJy	stat.error;phot.flux.density;em.radio
Isl_rms	RMS noise	The average background rms value of the island	mJy/beam	instr.det.noise
Majax	Major Axis	The FWHM of the major axis of the source, INCLUDING convolution with the 6-arcsec LOFAR beam	arcsec	phys.angsize
Masked_Fraction	Masked Fraction	The fraction of the source that is in the CLEAN mask	N/A	N/A
Minax	Minor Axis	The FWHM of the minor axis of the source, INCLUDING convolution with the 6-arcsec LOFAR beam	arcsec	phys.angsize
Mosaic_ID	Mosaic	The name of the mosaic in which the FITS image can be found	N/A	meta.id;obs.image
mosaic_url	Mosaic_url	DataLink to the corresponding mosaic	N/A	meta.id;obs.image
Number_Pointings	Number of pointings	Number of pointings that are mosaiced at the position of the source.	N/A	meta.number
PA	PA	The position angle of the major axis of the source measured east of north, INCLUDING convolution with the 6-arcsec LOFAR beam	deg	pos.posang
Peak_flux	Peak flux	The peak Stokes I flux density per beam of the source	mJy/beam	phot.flux.density;em.radio
RA	RA	Position from PyBDSF or combination of PyBDSF components	deg	pos.eq.ra;meta.main
S_Code	Morphological Code	A code that defines the source structure 'S' for single Gaussian, 'M' for multiple Gaussian, 'C' = a single-Gaussian source in an island with other sources	N/A	meta.code;src.morph
Source_Name	ID	The radio name of the source, automatically generated from RA and DEC in most cases	N/A	meta.id;meta.main
Total_flux	Total flux	The total, integrated Stokes I flux density of the source at the reference frequency	mJy	phot.flux.density;em.radio

VOTable Output Fields

The following fields are available in VOTable output. The verbosity level is a number intended to represent the relative importance of the field on a scale of 1 to 30. The services take a VERB argument. A field is included in the output if their verbosity level is less or equal VERB*10.

Name	Table Head	Description	Unit	UCD	Verb. Level
Source_Name	ID	The radio name of the source, automatically generated from RA and DEC in most cases	N/A	meta.id;meta.main	1
RA	RA	Position from PyBDSF or combination of PyBDSF components	deg	pos.eq.ra;meta.main	1
E_RA	error RA	Estimated by PyBDSF. Only fitting uncertainties are included	arcsec	stat.error;pos.eq.ra	1
DEC	Dec	Position from PyBDSF or combination of PyBDSF components	deg	pos.eq.dec;meta.main	1
E_DEC	error Dec	Estimated by PyBDSF. Only fitting uncertainties are included	arcsec	stat.error;pos.eq.dec	1
Peak_flux	Peak flux	The peak Stokes I flux density per beam of the source	mJy/beam	phot.flux.density;em.radio	1
E_Peak_flux	error Peak flux	The 1-sigma error on the peak flux density per beam of the source	mJy/beam	stat.error;phot.flux.density;em.radio	1
Total_flux	Total flux	The total, integrated Stokes I flux density of the source at the reference frequency	mJy	phot.flux.density;em.radio	1
E_Total_flux	error Total flux	The 1-sigma on the total flux density of the source	mJy	stat.error;phot.flux.density;em.radio	1
Majax	Major Axis	The FWHM of the major axis of the source, INCLUDING convolution with the 6-arcsec LOFAR beam	arcsec	phys.angsize	1
E_Maj	E_Maj	The 1-sigma error on the FWHM of the major axis of the source	arcsec	stat.error;phys.angsize	1
Minax	Minor Axis	The FWHM of the minor axis of the source, INCLUDING convolution with the 6-arcsec LOFAR beam	arcsec	phys.angsize	1
E_Min	E_Min	The 1-sigma error on the FWHM of the minor axis of the source	arcsec	stat.error;phys.angsize	1
DC_Maj	DC_Maj	The FWHM of the major axis of the source, after de-convolution with the 6-arcsec LOFAR beam	arcsec	phys.angsize	1
E_DC_Maj	E_DC_Maj	The 1-sigma error on the FWHM of the deconvolved major axis of the source	arcsec	stat.error;phys.angsize	1
DC_Min	DC_Min	The FWHM of the minor axis of the source, after de-convolution with the 6-arcsec LOFAR beam	arcsec	phys.angsize	1
E_DC_Min	E_DC_Min	The 1-sigma error on the FWHM of the deconvolved minor axis of the source	arcsec	stat.error;phys.angsize	1
PA	PA	The position angle of the major axis of the source measured east of north, INCLUDING convolution with the 6-arcsec LOFAR beam	deg	pos.posang	1
E_PA	E_PA	The 1-sigma error on the position angle of the major axis of the source	deg	stat.error;pos.posang	1
DC_PA	DC_PA	The position angle of the major axis of the source measured east of north, after de-convolution with the 6-arcsec LOFAR beam	deg	pos.posang	1
E_DC_PA	E_DC_PA	The 1-sigma error on the position angle of the deconvolved major axis of the source	deg	stat.error;pos.posang	1
Isl_rms	RMS noise	The average background rms value of the island	mJy/beam	instr.det.noise	1
S_Code	Morphological Code	A code that defines the source structure 'S' for single Gaussian, 'M' for multiple Gaussian, 'C' = a single-Gaussian source in an island with other sources	N/A	meta.code;src.morph	1
Mosaic_ID	Mosaic	The name of the mosaic in which the FITS image can be found	N/A	meta.id;obs.image	1
mosaic_url	Mosaic_url	DataLink to the corresponding mosaic	N/A	meta.id;obs.image	1
Masked_Fraction	Masked Fraction	The fraction of the source that is in the CLEAN mask	N/A	N/A	1
Number_Pointings	Number of pointings	Number of pointings that are mosaiced at the position of the source.	N/A	meta.number	20

Copyright, License, Acknowledgements

LoTSS Data Release 2 is licensed under the Creative Commons Attribution Share-Alike 3.0 License

VOResource XML (that's something exclusively for VO nerds)

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