A VLBI Software Correlator for Fast Radio Transients
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arXiv
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| Main Authors: | , , , , , , , , , , , , , , , |
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| Format: | Preprint |
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2024
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| _version_ | 1866913285936250880 |
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| author | Leung, Calvin Andrew, Shion Masui, Kiyoshi W. Brar, Charanjot Cassanelli, Tomas Chatterjee, Shami Kaspi, Victoria Khairy, Kholoud Lanman, Adam E. Lazda, Mattias Mena-Parra, Juan Noble, Gavin Pearlman, Aaron B. Rahman, Mubdi Sanghavi, Pranav Shah, Vishwangi |
| author_facet | Leung, Calvin Andrew, Shion Masui, Kiyoshi W. Brar, Charanjot Cassanelli, Tomas Chatterjee, Shami Kaspi, Victoria Khairy, Kholoud Lanman, Adam E. Lazda, Mattias Mena-Parra, Juan Noble, Gavin Pearlman, Aaron B. Rahman, Mubdi Sanghavi, Pranav Shah, Vishwangi |
| contents | One major goal in fast radio burst science is to detect fast radio bursts (FRBs) over a wide field of view without sacrificing the angular resolution required to pinpoint them to their host galaxies. Wide-field detection and localization capabilities have already been demonstrated using connected-element interferometry; the CHIME/FRB Outriggers project will push this further using widefield cylindrical telescopes as widefield outriggers for very long baseline interferometry (VLBI). This paper describes an offline VLBI software correlator written in Python for the CHIME/FRB Outriggers project. It includes features well-suited to modern widefield instruments like multibeaming/multiple phase center correlation, pulse gating including coherent dedispersion, and a novel correlation algorithm based on the quadratic estimator formalism. This algorithm mitigates sensitivity loss which arises in instruments where the windowing and channelization is done outside the VLBI correlator at each station, which accounts for a 30 percent sensitivity drop away from the phase center. Our correlation algorithm recovers this sensitivity on both simulated and real data. As an end to end check of our software, we have written a preliminary pipeline for VLBI calibration and single-pulse localization, which we use in Lanman et al. (2024) to verify the astrometric accuracy of the CHIME/FRB Outriggers array. |
| format | Preprint |
| id |
arxiv_https___arxiv_org_abs_2403_05631 |
| institution | arXiv |
| publishDate | 2024 |
| record_format | arxiv |
| spellingShingle | A VLBI Software Correlator for Fast Radio Transients Leung, Calvin Andrew, Shion Masui, Kiyoshi W. Brar, Charanjot Cassanelli, Tomas Chatterjee, Shami Kaspi, Victoria Khairy, Kholoud Lanman, Adam E. Lazda, Mattias Mena-Parra, Juan Noble, Gavin Pearlman, Aaron B. Rahman, Mubdi Sanghavi, Pranav Shah, Vishwangi Instrumentation and Methods for Astrophysics High Energy Astrophysical Phenomena One major goal in fast radio burst science is to detect fast radio bursts (FRBs) over a wide field of view without sacrificing the angular resolution required to pinpoint them to their host galaxies. Wide-field detection and localization capabilities have already been demonstrated using connected-element interferometry; the CHIME/FRB Outriggers project will push this further using widefield cylindrical telescopes as widefield outriggers for very long baseline interferometry (VLBI). This paper describes an offline VLBI software correlator written in Python for the CHIME/FRB Outriggers project. It includes features well-suited to modern widefield instruments like multibeaming/multiple phase center correlation, pulse gating including coherent dedispersion, and a novel correlation algorithm based on the quadratic estimator formalism. This algorithm mitigates sensitivity loss which arises in instruments where the windowing and channelization is done outside the VLBI correlator at each station, which accounts for a 30 percent sensitivity drop away from the phase center. Our correlation algorithm recovers this sensitivity on both simulated and real data. As an end to end check of our software, we have written a preliminary pipeline for VLBI calibration and single-pulse localization, which we use in Lanman et al. (2024) to verify the astrometric accuracy of the CHIME/FRB Outriggers array. |
| title | A VLBI Software Correlator for Fast Radio Transients |
| topic | Instrumentation and Methods for Astrophysics High Energy Astrophysical Phenomena |
| url | https://arxiv.org/abs/2403.05631 |