Information on Service 'LoTSS-DR3 pointings'

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In this data release from the LOw-Frequency ARray (LOFAR) Two-metre Sky Survey (LoTSS) we present 120-168 MHz images covering 88% of the northern sky. The individual pointing images (at 6'' and 20'' resolution) were derived from 12,950 hrs (18.6 PB) of LOFAR High Band Antenna data which were processed through fully automated direction-independent and direction-dependent calibration pipelines that correct for instrumental effects as well as spatially and temporally varying ionospheric distortions. The Stokes I images were then combined, accounting for the rms noise level and telescope beam, to form the final Stokes I mosaic images at 6'' and 20'' resolution, with a central frequency of 144MHz. From the 6'' resolution Stokes mosaics we derived a catalogue of 13,664,379 radio sources (consisting of 16,943,656 Gaussian components), the majority of which have never been detected at radio wavelengths before. These mosaics have a median rms sensitivity of 92 μJy/beam; a random and systematic flux density scale accuracy of approximately 6% and 2%, respectively; an astrometric accuracy of 0.24''; and we estimate that we detect more than 95% of sources with integrated flux densities exceeding nine times the local root mean square noise. To enable thorough scientific exploitation of this unique dataset, we have published two sub-collections. The first contains all the Stokes I mosaic products described above. The second contains the individual pointing products, including calibrated uv data (measurement sets and direction-dependent calibration solutions) to allow for re-imaging or post-processing; Stokes I images at 6' ' and 20'' resolution (with associated scaling factors required to reproduce the mosaic images); Stokes V images at 6'' resolution for each observing epoch; and Stokes Q and U image cubes at 20'' and 4' resolution. This service queries the data products associated with the individual pointings hosted on the Surf Data Repository.

For a list of all services and tables belonging to this service's resource, see Information on resource 'lotss_dr3/q'

Overview

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This service is published as follows:

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):

NameTable Head DescriptionUnitUCD
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.

NameTable Head DescriptionUnitUCD
_r Dist. Distance to cone center deg pos.distance
accsize File size Size of the data in bytes byte VOX:Image_FileSize
bandpassHi Band upper Upper limit of the bandpass (in BandPass_Unit units). m VOX:BandPass_HiLimit
bandpassId Bandpass Freeform name of the bandpass used. N/A VOX:BandPass_ID
bandpassLo Band lower Lower limit of the bandpass (in BandPass_Unit units). m VOX:BandPass_LoLimit
bandpassRefval Band ref. Characteristic quantity for the bandpass of the image. m VOX:BandPass_RefValue
bandpassUnit Bandpass unit Unit of bandpass specifications. N/A VOX:BandPass_Unit
centerAlpha Ctr. RA Approximate center of pointing, RA. deg pos.eq.ra;meta.main
centerDelta Ctr. Dec Approximate center of pointing, Dec. deg pos.eq.dec;meta.main
dateObs Obs. date Epoch at midpoint of observation. d VOX:Image_MJDateObs
equinox Equinox Equinox of the given coordinates. yr VOX:STC_CoordEquinox
instrument Instrument Identifier of the originating instrument. N/A meta.id;instr
mime Type MIME type of the file served N/A meta.code.mime
pointing_id Pointing ID The name of the pointing. N/A meta.id;meta.main
refFrame Ref. Frame Coordinate system reference frame. N/A VOX:STC_CoordRefFrame
related_products Related products Link to related products for the observation. N/A meta.ref.url
sdr_url SDR record SURF Data Repository record for this pointing. N/A meta.ref.url

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.

NameTable Head DescriptionUnitUCD Verb. Level
centerAlpha Ctr. RA Approximate center of pointing, RA. deg pos.eq.ra;meta.main 0
centerDelta Ctr. Dec Approximate center of pointing, Dec. deg pos.eq.dec;meta.main 0
dateObs Obs. date Epoch at midpoint of observation. d VOX:Image_MJDateObs 0
sdr_url SDR record SURF Data Repository record for this pointing. N/A meta.ref.url 1
related_products Related products Link to related products for the observation. N/A meta.ref.url 1
_r Dist. Distance to cone center deg pos.distance 10
bandpassId Bandpass Freeform name of the bandpass used. N/A VOX:BandPass_ID 10
accsize File size Size of the data in bytes byte VOX:Image_FileSize 11
instrument Instrument Identifier of the originating instrument. N/A meta.id;instr 15
mime Type MIME type of the file served N/A meta.code.mime 20
pointing_id Pointing ID The name of the pointing. N/A meta.id;meta.main 20
refFrame Ref. Frame Coordinate system reference frame. N/A VOX:STC_CoordRefFrame 20
equinox Equinox Equinox of the given coordinates. yr VOX:STC_CoordEquinox 20
bandpassUnit Bandpass unit Unit of bandpass specifications. N/A VOX:BandPass_Unit 20
bandpassRefval Band ref. Characteristic quantity for the bandpass of the image. m VOX:BandPass_RefValue 20
bandpassHi Band upper Upper limit of the bandpass (in BandPass_Unit units). m VOX:BandPass_HiLimit 20
bandpassLo Band lower Lower limit of the bandpass (in BandPass_Unit units). m VOX:BandPass_LoLimit 20
accref Identifier Identifier used to reference the pointing in DataLink. N/A meta.id;meta.main 25
owner Owner Owner of the data N/A N/A 25
embargo Embargo ends Date the data will become/became public a N/A 25
lofar_obsids LOFAR ObsID(s) ObsID(s) of the LOFAR observation(s) used for imaging the central pointing. N/A meta.id;obs 25
dateFirstObs Date first obs. Epoch of first observation d time.epoch;time.start 25
dateLastObs Date last obs. Epoch of last observation d time.epoch;time.end 25
dateAllObs Date all obs. Epoch of all observations N/A time.epoch 25

Copyright, License, Acknowledgements

LoTSS Data Release 3 is licensed under the Creative Commons Attribution Share-Alike 3.0 License

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