Polarimetric Properties of Event Horizon Telescope Targets from ALMA
文献类型：期刊论文
| 作者 | Goddi,Ciriaco93,94; Martí-Vidal,Iván95,96; Messias,Hugo97; Bower,Geoffrey C.98; Broderick,Avery E.99,100,101; Dexter,Jason102; Marrone,Daniel P.103; Moscibrodzka,Monika93; Nagai,Hiroshi104,105; Algaba,Juan Carlos106 |
| 刊名 | The Astrophysical Journal Letters
 |
| 出版日期 | 2021-03-01 |
| 卷号 | 910期号:1 |
| 关键词 | Magnetic fields Relativistic jets Active galactic nuclei Radio jets Polarimetry Interferometry Long baseline interferometry Galactic center Supermassive black holes Blazars Radio galaxies Quasars |
| ISSN号 | 2041-8205 |
| DOI | 10.3847/2041-8213/abee6a |
| 英文摘要 | Abstract We present the results from a full polarization study carried out with the Atacama Large Millimeter/submillimeter Array (ALMA) during the first Very Long Baseline Interferometry (VLBI) campaign, which was conducted in 2017 April in the λ3 mm and λ1.3 mm bands, in concert with the Global mm-VLBI Array (GMVA) and the Event Horizon Telescope (EHT), respectively. We determine the polarization and Faraday properties of all VLBI targets, including Sgr A*, M87, and a dozen radio-loud active galactic nuclei (AGNs), in the two bands at several epochs in a time window of 10 days. We detect high linear polarization fractions (2%–15%) and large rotation measures (RM > 103.3–105.5 rad m?2), confirming the trends of previous AGN studies at millimeter wavelengths. We find that blazars are more strongly polarized than other AGNs in the sample, while exhibiting (on average) order-of-magnitude lower RM values, consistent with the AGN viewing angle unification scheme. For Sgr A* we report a mean RM of (?4.2 ± 0.3) × 105 rad m?2 at 1.3 mm, consistent with measurements over the past decade and, for the first time, an RM of (–2.1 ± 0.1) × 105 rad m?2 at 3 mm, suggesting that about half of the Faraday rotation at 1.3 mm may occur between the 3 mm photosphere and the 1.3 mm source. We also report the first unambiguous measurement of RM toward the M87 nucleus at millimeter wavelengths, which undergoes significant changes in magnitude and sign reversals on a one year timescale, spanning the range from ?1.2 to 0.3 × 105 rad m?2 at 3 mm and ?4.1 to 1.5 × 105 rad m?2 at 1.3 mm. Given this time variability, we argue that, unlike the case of Sgr A*, the RM in M87 does not provide an accurate estimate of the mass accretion rate onto the black hole. We put forward a two-component model, comprised of a variable compact region and a static extended region, that can simultaneously explain the polarimetric properties observed by both the EHT (on horizon scales) and ALMA (which observes the combined emission from both components). These measurements provide critical constraints for the calibration, analysis, and interpretation of simultaneously obtained VLBI data with the EHT and GMVA. |
| 语种 | 英语 |
| WOS记录号 | IOP:2041-8205-910-1-ABEE6A |
| 出版者 | The American Astronomical Society |
| 源URL | [http://ir.bao.ac.cn/handle/114a11/60308]  |
| 专题 | 中国科学院国家天文台 |
| 通讯作者 | Goddi,Ciriaco |
| 作者单位 | 1.Nederlandse Onderzoekschool voor Astronomie (NOVA), P.O. Box 9513, 2300 RA Leiden, The Netherlands 2.Princeton Center for Theoretical Science, Jadwin Hall, Princeton University, Princeton, NJ 08544, USA 3.Data Science Institute, University of Arizona, 1230 N. Cherry Ave., Tucson, AZ 85721, USA 4.Cornell Center for Astrophysics and Planetary Science, Cornell University, Ithaca, NY 14853, USA 5.Anton Pannekoek Institute for Astronomy, University of Amsterdam, Science Park 904, 1098 XH, Amsterdam, The Netherlands 6.Shanghai Astronomical Observatory, Chinese Academy of Sciences, 80 Nandan Road, Shanghai 200030, People’s Republic of China 7.Key Laboratory of Radio Astronomy, Chinese Academy of Sciences, Nanjing 210008, People’s Republic of China 8.Physics Department, Fairfield University, 1073 North Benson Road, Fairfield, CT 06824, USA 9.Department of Space, Earth and Environment, Chalmers University of Technology, Onsala Space Observatory, SE-43992 Onsala, Sweden 10.Mizusawa VLBI Observatory, National Astronomical Observatory of Japan, 2-12 Hoshigaoka, Mizusawa, Oshu, Iwate 023-0861, Japan |
| 推荐引用方式 GB/T 7714 | Goddi,Ciriaco,Martí-Vidal,Iván,Messias,Hugo,et al. Polarimetric Properties of Event Horizon Telescope Targets from ALMA[J]. The Astrophysical Journal Letters,2021,910(1). |
| APA | Goddi,Ciriaco.,Martí-Vidal,Iván.,Messias,Hugo.,Bower,Geoffrey C..,Broderick,Avery E..,...&Valtonen,Mauri.(2021).Polarimetric Properties of Event Horizon Telescope Targets from ALMA.The Astrophysical Journal Letters,910(1). |
| MLA | Goddi,Ciriaco,et al."Polarimetric Properties of Event Horizon Telescope Targets from ALMA".The Astrophysical Journal Letters 910.1(2021). |
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来源：国家天文台
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