Verification of the Polarimetric Capability of the East Asia VLBI Network
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arXiv
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| Main Authors: | , , , , , , , , , , , , |
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| Format: | Preprint |
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2026
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| _version_ | 1866908915527057408 |
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| author | Lee, Yunjeong Park, Jongho Byun, Do-Young Kam, Minchul Hada, Kazuhiro Algaba, Juan Carlos Kim, Sanghyun Shen, Zhiqiang Oh, Junghwan Kang, Sincheol Jeong, Hyeon-Woo Cheong, Whee Yeon Lee, Sang-Sung |
| author_facet | Lee, Yunjeong Park, Jongho Byun, Do-Young Kam, Minchul Hada, Kazuhiro Algaba, Juan Carlos Kim, Sanghyun Shen, Zhiqiang Oh, Junghwan Kang, Sincheol Jeong, Hyeon-Woo Cheong, Whee Yeon Lee, Sang-Sung |
| contents | The East Asia VLBI Network (EAVN) has recently enabled dual-polarization observations at $22$ and $43\,\mathrm{GHz}$. We present the first systematic verification of its polarimetric performance using EAVN observations of M87, 3C 279, 3C 273, and OJ 287, calibrated with the GPCAL pipeline and evaluated against near-contemporaneous VLBA images at comparable frequencies. Most stations show stable polarimetric leakages with amplitudes of $5$-$10\%$ over monthly timescales. While several VERA stations exhibit D-term phase variations between epochs, we attribute these to field-rotator (FR) offsets and demonstrate that phase stability is restored after applying the analytically derived FR corrections. The resulting linear-polarization morphologies and EVPAs broadly agree with the VLBA results within uncertainties; fractional polarization measured by the EAVN tends to be slightly higher near polarization peaks. Although exact one-to-one comparisons are limited by moderate frequency and epoch differences, the combined evidence indicates robust EAVN polarimetric calibration and imaging capabilities at $22$ and $43\,\mathrm{GHz}$. These results support the scientific capability of EAVN polarimetry and lay the groundwork for expanded, higher-fidelity polarimetric studies in East Asia. |
| format | Preprint |
| id |
arxiv_https___arxiv_org_abs_2603_25185 |
| institution | arXiv |
| publishDate | 2026 |
| record_format | arxiv |
| spellingShingle | Verification of the Polarimetric Capability of the East Asia VLBI Network Lee, Yunjeong Park, Jongho Byun, Do-Young Kam, Minchul Hada, Kazuhiro Algaba, Juan Carlos Kim, Sanghyun Shen, Zhiqiang Oh, Junghwan Kang, Sincheol Jeong, Hyeon-Woo Cheong, Whee Yeon Lee, Sang-Sung Instrumentation and Methods for Astrophysics High Energy Astrophysical Phenomena The East Asia VLBI Network (EAVN) has recently enabled dual-polarization observations at $22$ and $43\,\mathrm{GHz}$. We present the first systematic verification of its polarimetric performance using EAVN observations of M87, 3C 279, 3C 273, and OJ 287, calibrated with the GPCAL pipeline and evaluated against near-contemporaneous VLBA images at comparable frequencies. Most stations show stable polarimetric leakages with amplitudes of $5$-$10\%$ over monthly timescales. While several VERA stations exhibit D-term phase variations between epochs, we attribute these to field-rotator (FR) offsets and demonstrate that phase stability is restored after applying the analytically derived FR corrections. The resulting linear-polarization morphologies and EVPAs broadly agree with the VLBA results within uncertainties; fractional polarization measured by the EAVN tends to be slightly higher near polarization peaks. Although exact one-to-one comparisons are limited by moderate frequency and epoch differences, the combined evidence indicates robust EAVN polarimetric calibration and imaging capabilities at $22$ and $43\,\mathrm{GHz}$. These results support the scientific capability of EAVN polarimetry and lay the groundwork for expanded, higher-fidelity polarimetric studies in East Asia. |
| title | Verification of the Polarimetric Capability of the East Asia VLBI Network |
| topic | Instrumentation and Methods for Astrophysics High Energy Astrophysical Phenomena |
| url | https://arxiv.org/abs/2603.25185 |