ALMA High-frequency Long Baseline Campaign in 2017: Band-to-band Phase Referencing in Submillimeter Waves
書誌事項
- 公開日
- 2020-03-01
- 資源種別
- journal article
- 権利情報
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- https://iopscience.iop.org/page/copyright
- https://iopscience.iop.org/info/page/text-and-data-mining
- DOI
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- 10.3847/1538-4365/ab6b20
- 公開者
- American Astronomical Society
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説明
<jats:title>Abstract</jats:title> <jats:p>In 2017, an Atacama Large Millimeter/submillimeter Array (ALMA) high-frequency long baseline campaign was organized to test image capabilities with baselines up to 16 km at submillimeter (submm) wavelengths. We investigated image qualities using ALMA receiver Bands 7, 8, 9, and 10 (285–875 GHz) by adopting band-to-band (B2B) phase referencing in which a phase calibrator is tracked at a lower frequency. For B2B phase referencing, it is expected that a closer phase calibrator to a target can be used, comparing to standard in-band phase referencing. In the first step, it is ensured that an instrumental phase offset difference between low- and high-frequency Bands can be removed using a differential gain calibration in which a phase calibrator is certainly detected while frequency switching. In the next step, comparative experiments are arranged to investigate the image quality between B2B and in-band phase referencing with phase calibrators at various separation angles. In the final step, we conducted long baseline imaging tests for a quasar at 289 GHz in Band 7 and 405 GHz in Band 8 and complex structure sources of HL Tau and VY CMa at ∼670 GHz in Band 9. The B2B phase referencing was successfully applied, allowing us to achieve an angular resolution of 14 × 11 and 10 × 8 mas for HL Tau and VY CMa, respectively. There is a high probability of finding a low-frequency calibrator within 5.°4 in B2B phase referencing, bright enough to use an 8 s scan length combined with a 7.5 GHz bandwidth.</jats:p>
収録刊行物
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- The Astrophysical Journal Supplement Series
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The Astrophysical Journal Supplement Series 247 (1), 23-, 2020-03-01
American Astronomical Society
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詳細情報 詳細情報について
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- CRID
- 1361694594358423168
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- ISSN
- 15384365
- 00670049
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- 資料種別
- journal article
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- データソース種別
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- Crossref
- KAKEN