- ID:
- ivo://astron.nl/apertif_dr1/q/apertif_dr1_continuum_images
- Title:
- Apertif DR1 - Continuum images
- Short Name:
- Continuum images
- Date:
- 21 Oct 2024 00:54:16
- Publisher:
- ASTRON
- Description:
- 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. This service queries the continuum images from the first data release of Apertif. Multi-frequency synthesis (mfs) Stokes I images are produced over the full frequency range (1292.5– 1430 MHz) and saved as fits files for each beam. The size of the continuum images is 3.4 deg × 3.4 deg (3073 × 3073 pixels, with 4''/pixel). The median noise in the continuum images is 41.4 uJy/beam and the median angular resolution is 11.6''/sin(declination). A companion VO table provides a continuum source catalog based on all continuum images contained in this data release and is described in Kutkin et al. (2022) (see https://vo.astron.nl/apertif_dr1/q/apertif_dr1_catalogue/form).
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- ID:
- ivo://astron.nl/apertif_dr1/q/apertif_dr1_calibrated_visibilities
- Title:
- Apertif DR1 - Field calibrated visibilities
- Short Name:
- CalVis
- Date:
- 21 Oct 2024 00:54:16
- Publisher:
- ASTRON
- Description:
- 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. This service queries the calibrated visibility measurement sets. The calibrated visibility data, with cross-calibration and self-calibration solutions applied, are currently stored as an intermediate data product at full time and spectral resolution. These are stored on tape with the raw data 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.
- ID:
- ivo://astron.nl/apertif_dr1/q/apertif_dr1_raw_visibilities
- Title:
- Apertif DR1 - Field raw visibilities
- Short Name:
- RawVis
- Date:
- 21 Oct 2024 00:54:16
- Publisher:
- ASTRON
- Description:
- 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 survey fields. 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.
- ID:
- ivo://astron.nl/apertif_dr1/q/apertif_dr1_flux_cal_visibilities
- Title:
- Apertif DR1 - Flux calibrator raw visibilities
- Short Name:
- FluxCalVis
- Date:
- 21 Oct 2024 00:54:16
- Publisher:
- ASTRON
- Description:
- 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 flux 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.
- ID:
- ivo://astron.nl/apertif_dr1/q/apertif_dr1_spectral_cubes
- Title:
- Apertif DR1 - HI spectral cubes
- Short Name:
- Spectral cubes
- Date:
- 21 Oct 2024 00:54:16
- Publisher:
- ASTRON
- Description:
- 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. This service queries the spectral line cubes from the first data release of Apertif. Four line cubes are produced over a set of different frequency ranges as follows. Cube 0: 1292.5–1337.1 MHz, Cube 1: 1333.1–1377.7 MHz, Cube 2: 1373.8–1418.4 MHz, Cube 3: 1414.5–1429.3 MHz. Cube 3 is produced at full spectral resolution of 12.2 kHz while other cubes are produced with a 3-channel averaging at 36.6 kHz resolution. The cubes have a spatial extent of 1.1 deg × 1.1 deg (661 × 661 pixels, with 6''/pixel). The median noise for all line cubes, with a spectral resolution of 36.6 kHz, is 1.6 mJy/beam, corresponding to a 3-σ H I column density sensitivity of 1.8 × 10^20 atoms cm^−2 over 20 km s^−1 (for a median angular resolution of 24″ × 15″). The corresponding dirty beam cubes are also released to allow offline cleaning of source emission.
- ID:
- ivo://astron.nl/apertif_dr1/q/apertif_dr1_pol_cal_visibilities
- Title:
- Apertif DR1 - Polarization calibrator raw visibilities
- Short Name:
- PolCalVis
- Date:
- 21 Oct 2024 00:54:16
- Publisher:
- ASTRON
- Description:
- 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.
- ID:
- ivo://astron.nl/apertif_dr1/q/apertif_dr1_polarization_cubes
- Title:
- Apertif DR1 - Polarization cubes
- Short Name:
- Pol. cubes
- Date:
- 21 Oct 2024 00:54:16
- Publisher:
- ASTRON
- Description:
- 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. This service queries the polarization cubes from the first data release of Apertif. In order to prevent bandwidth depolarization and enable rotation measure synthesis studies, Stokes Q and U cubes with a frequency resolution of 6.25 MHz are produced. The cubes have a smaller spatial extent of 2.7 deg × 2.7 deg (2049 × 2049 pixels, with 4''/pixel ) than the continuum or Stokes V images but still extend well beyond the primary beam.
- ID:
- ivo://astron.nl/apertif_dr1/q/apertif_dr1_catalogue
- Title:
- Apertif DR1 - Source catalogue
- Short Name:
- DR1 Catalogue
- Date:
- 21 Oct 2024 00:54:16
- Publisher:
- ASTRON
- Description:
- This service queries the continuum catalogue based on the first data release of Apertif continuum images at a central frequency 1355 MHz, with a bandwidth of ~150 MHz and angular resolution of up to 10''. The catalogue contains 249672 radio sources, many of which have been detected for the first time at these frequencies. Source extraction methods are described in Kutkin et al. 2022. A companion VO table contains the continuum images corresponding to this catalogue (see https://vo.astron.nl/apertif_dr1/q/apertif_dr1_continuum_images/form).
