Information on Service 'Apertif DR1 - Polarization calibrator raw visibilities'

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Further access options are discussed below

Apertif is a phased-array feed system for the Westerbork Synthesis Radio Telescope (WSRT), providing forty instantaneous beams over 300 MHz of bandwidth. This first data release includes observations in the first year of survey operations, from 1 July 2019 through 30 June 2020. The data release includes all raw observational data for a total of 221 observations of 160 independent target fields, covering approximately one thousand square degrees of sky. A subset of processed data products, meeting specified quality assessment criteria as outlined in Adams et al. (2022), are also released. Images and cubes are released on a per beam basis, and 3374 beams (of 7640 considered) are included in this data release. The processed data products are only available for the upper 150 MHz of the band over the range 1280–1430 MHz. The first 12.5 MHz of data are flagged due to persistent RFI resulting in a nominal bandwidth of 137.5 MHz and central frequency of 1361.25 MHz. The data products are not primary-beam corrected, however the primary-beam images are provided separately that may be used for mosaicking or for correction of individual images. The raw visibility data are provided as separate collections for the survey fields, flux calibrator and polarization calibrator observations. The tables can be joined to identify the associated calibrators for a target observation. This service queries the raw visibilities for the polarization calibrator. These are stored on tape and are not immediately available for download. The data release documentation should be consulted for up-to-date information on how to access the data.

For a list of all services and tables belonging to this service's resource, see Information on resource 'Apertif DR-1'

Overview

You can access this service using:

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:

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
beam Beam number Beam number N/A meta.id
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
obsid ObsId Observation id N/A meta.id
RA Alpha (ICRS) Right Ascension (ICRS decimal) deg pos.eq.ra
SR Search Radius Search radius deg N/A
target Field Name Name of the field N/A meta.id

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
accref Access Access url for the data N/A N/A
bandwidth Band width N/A MHz em.frequency
beam Beam ID N/A N/A meta.id
central_frequency Ctr. frequency N/A MHz em.frequency
dataproduct_subtype Sub type N/A N/A meta.id
dataproduct_type Type N/A N/A meta.id
dec Declination N/A deg pos.eq.dec;meta.main
duration Duration N/A h time.duration;obs.exposure
equinox equinox N/A N/A meta.text
FOV FOV N/A deg phys.angSize;instr.fov
n_channels # channels N/A N/A meta.number
obsid Obs ID N/A N/A meta.id
product_key Product Key N/A N/A meta.id
pub_did P. DID Dataset identifier assigned by the publisher N/A meta.id;meta.main
quality quality N/A N/A meta.id
ra Right ascension N/A deg pos.eq.ra;meta.main
t_max End time N/A N/A time.end;obs.exposure
t_min Start time N/A N/A time.start;obs.exposure
target Target name N/A N/A meta.id
task_id Task ID N/A N/A meta.id
used_for Calibrated obs Observation calibrated with this calibrator N/A meta.id

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
accref Access Access url for the data N/A N/A 1
_r Dist. Distance to cone center deg pos.distance 10
pub_did P. DID Dataset identifier assigned by the publisher N/A meta.id;meta.main 15
target Target name N/A N/A meta.id 20
ra Right ascension N/A deg pos.eq.ra;meta.main 20
dec Declination N/A deg pos.eq.dec;meta.main 20
beam Beam ID N/A N/A meta.id 20
FOV FOV N/A deg phys.angSize;instr.fov 20
central_frequency Ctr. frequency N/A MHz em.frequency 20
n_channels # channels N/A N/A meta.number 20
bandwidth Band width N/A MHz em.frequency 20
t_min Start time N/A N/A time.start;obs.exposure 20
t_max End time N/A N/A time.end;obs.exposure 20
duration Duration N/A h time.duration;obs.exposure 20
task_id Task ID N/A N/A meta.id 20
obsid Obs ID N/A N/A meta.id 20
dataproduct_type Type N/A N/A meta.id 20
dataproduct_subtype Sub type N/A N/A meta.id 20
product_key Product Key N/A N/A meta.id 20
equinox equinox N/A N/A meta.text 20
quality quality N/A N/A meta.id 20
used_for Calibrated obs Observation calibrated with this calibrator N/A meta.id 20

Copyright, License, Acknowledgements

If you use this data, cite Adams et al. 2022 (2022A&A...667A..38A). Additionally, you can cite the service reference. The Apertif data release 1 is licensed under the Creative Commons Attribution 3.0 License

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