ALMA Confirmation of Millimeter Time Variability in the Gamma-Ray Detected Seyfert Galaxy GRS 1734-292
GRS 1734-292 is a radio-quiet galaxy, exhibiting neither intense starburst nor jet activities. However, Fermi-LAT detected this object in the GeV band. The origin of nonthermal activity in this Seyfert galaxy is an intriguing question. We report Atacama Large Millimeter/submillimeter Array observati...
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| Format: | Article |
| Language: | English |
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IOP Publishing
2024-01-01
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| Series: | The Astrophysical Journal |
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| Online Access: | https://doi.org/10.3847/1538-4357/ad2fae |
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| author | Tomonari Michiyama Yoshiyuki Inoue Akihiro Doi Tomoya Yamada Yasushi Fukazawa Hidetoshi Kubo Samuel Barnier |
| author_facet | Tomonari Michiyama Yoshiyuki Inoue Akihiro Doi Tomoya Yamada Yasushi Fukazawa Hidetoshi Kubo Samuel Barnier |
| author_sort | Tomonari Michiyama |
| collection | DOAJ |
| description | GRS 1734-292 is a radio-quiet galaxy, exhibiting neither intense starburst nor jet activities. However, Fermi-LAT detected this object in the GeV band. The origin of nonthermal activity in this Seyfert galaxy is an intriguing question. We report Atacama Large Millimeter/submillimeter Array observations of GRS 1734-292 at frequencies of 97.5, 145, and 225 GHz. These observations confirmed the millimeter excess within the central ⪅100 pc region and its time variability based on two separate observations conducted 4 days apart. The timescale of variability aligns with the light-crossing time for a compact source smaller than <100 Schwarzschild radius. If we take into account the power-law synchrotron emission originating from the corona (i.e., the hot plasma located above the accretion disk), the millimeter spectrum indicates the coronal magnetic field of ≈10 G and the size of ≈10 Schwarzschild radius. An alternative explanation for this millimeter emission could be synchrotron and free–free emission from disk winds (i.e., fast wide-opening angle outflows from the disk) with the size of ≈10 pc, although it may be difficult to explain the fast variability. Future millimeter observations with higher resolution (<0.″01) will enable the differentiation between these two scenarios. Such observations will provide insights into the acceleration sites of high-energy particles at the core of active galactic nuclei. |
| first_indexed | 2024-04-24T12:13:13Z |
| format | Article |
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| issn | 1538-4357 |
| language | English |
| last_indexed | 2024-04-24T12:13:13Z |
| publishDate | 2024-01-01 |
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| series | The Astrophysical Journal |
| spelling | doaj.art-156329f49fcf4db38cf3a15cb51ef7be2024-04-08T09:27:02ZengIOP PublishingThe Astrophysical Journal1538-43572024-01-0196516810.3847/1538-4357/ad2faeALMA Confirmation of Millimeter Time Variability in the Gamma-Ray Detected Seyfert Galaxy GRS 1734-292Tomonari Michiyama0https://orcid.org/0000-0003-2475-7983Yoshiyuki Inoue1https://orcid.org/0000-0002-7272-1136Akihiro Doi2https://orcid.org/0000-0003-4384-9568Tomoya Yamada3Yasushi Fukazawa4https://orcid.org/0000-0002-0921-8837Hidetoshi Kubo5https://orcid.org/0000-0001-9159-9853Samuel Barnier6Department of Earth and Space Science, Graduate School of Science, Osaka University , 1-1, Machikaneyama, Toyonaka, Osaka 560-0043, Japan ; t.michiyama.astr@gmail.com; National Astronomical Observatory of Japan, National Institutes of Natural Sciences , 2-21-1 Osawa, Mitaka, Tokyo 181-8588, Japan; Faculty of Information Science, Shunan University , 843-4-2, Gakuendai, Shunan, Yamaguchi 745-8566, JapanDepartment of Earth and Space Science, Graduate School of Science, Osaka University , 1-1, Machikaneyama, Toyonaka, Osaka 560-0043, Japan ; t.michiyama.astr@gmail.com; Interdisciplinary Theoretical & Mathematical Science Program (iTHEMS) , RIKEN, 2-1 Hirosawa, Saitama 351-0198, Japan; Kavli Institute for the Physics and Mathematics of the Universe (WPI), UTIAS, The University of Tokyo , 5-1-5 Kashiwanoha, Kashiwa, Chiba 277-8583, JapanThe Institute of Space and Astronautical Science , Japan Aerospace Exploration Agency, 3-1-1 Yoshinodai, Chuou-ku, Sagamihara, Kanagawa 252-5210, Japan; Department of Space and Astronautical Science, SOKENDAI , 3-1-1 Yoshinodai, Chuou-ku, Sagamihara, Kanagawa 252-5210, JapanDepartment of Earth and Space Science, Graduate School of Science, Osaka University , 1-1, Machikaneyama, Toyonaka, Osaka 560-0043, Japan ; t.michiyama.astr@gmail.comDepartment of Physical Science, Hiroshima University , 1-3-1 Kagamiyama, Higashi-Hiroshima, Hiroshima 739-8526, Japan; Hiroshima Astrophysical Science Center, Hiroshima University , 1-3-1 Kagamiyama, Higashi-Hiroshima, Hiroshima 739-8526, Japan; Core Research for Energetic Universe (Core-U), Hiroshima University , 1-3-1 Kagamiyama, Higashi-Hiroshima, Hiroshima 739-8526, JapanInstitute for Cosmic Ray Research, University of Tokyo , 5-1-5, Kashiwa-no-ha, Kashiwa, Chiba 277-8582, JapanDepartment of Earth and Space Science, Graduate School of Science, Osaka University , 1-1, Machikaneyama, Toyonaka, Osaka 560-0043, Japan ; t.michiyama.astr@gmail.com; National Astronomical Observatory of Japan, National Institutes of Natural Sciences , 2-21-1 Osawa, Mitaka, Tokyo 181-8588, JapanGRS 1734-292 is a radio-quiet galaxy, exhibiting neither intense starburst nor jet activities. However, Fermi-LAT detected this object in the GeV band. The origin of nonthermal activity in this Seyfert galaxy is an intriguing question. We report Atacama Large Millimeter/submillimeter Array observations of GRS 1734-292 at frequencies of 97.5, 145, and 225 GHz. These observations confirmed the millimeter excess within the central ⪅100 pc region and its time variability based on two separate observations conducted 4 days apart. The timescale of variability aligns with the light-crossing time for a compact source smaller than <100 Schwarzschild radius. If we take into account the power-law synchrotron emission originating from the corona (i.e., the hot plasma located above the accretion disk), the millimeter spectrum indicates the coronal magnetic field of ≈10 G and the size of ≈10 Schwarzschild radius. An alternative explanation for this millimeter emission could be synchrotron and free–free emission from disk winds (i.e., fast wide-opening angle outflows from the disk) with the size of ≈10 pc, although it may be difficult to explain the fast variability. Future millimeter observations with higher resolution (<0.″01) will enable the differentiation between these two scenarios. Such observations will provide insights into the acceleration sites of high-energy particles at the core of active galactic nuclei.https://doi.org/10.3847/1538-4357/ad2faeAstrophysical black holesBlack hole physicsBlack holesSupermassive black holesActive galactic nucleiSeyfert galaxies |
| spellingShingle | Tomonari Michiyama Yoshiyuki Inoue Akihiro Doi Tomoya Yamada Yasushi Fukazawa Hidetoshi Kubo Samuel Barnier ALMA Confirmation of Millimeter Time Variability in the Gamma-Ray Detected Seyfert Galaxy GRS 1734-292 The Astrophysical Journal Astrophysical black holes Black hole physics Black holes Supermassive black holes Active galactic nuclei Seyfert galaxies |
| title | ALMA Confirmation of Millimeter Time Variability in the Gamma-Ray Detected Seyfert Galaxy GRS 1734-292 |
| title_full | ALMA Confirmation of Millimeter Time Variability in the Gamma-Ray Detected Seyfert Galaxy GRS 1734-292 |
| title_fullStr | ALMA Confirmation of Millimeter Time Variability in the Gamma-Ray Detected Seyfert Galaxy GRS 1734-292 |
| title_full_unstemmed | ALMA Confirmation of Millimeter Time Variability in the Gamma-Ray Detected Seyfert Galaxy GRS 1734-292 |
| title_short | ALMA Confirmation of Millimeter Time Variability in the Gamma-Ray Detected Seyfert Galaxy GRS 1734-292 |
| title_sort | alma confirmation of millimeter time variability in the gamma ray detected seyfert galaxy grs 1734 292 |
| topic | Astrophysical black holes Black hole physics Black holes Supermassive black holes Active galactic nuclei Seyfert galaxies |
| url | https://doi.org/10.3847/1538-4357/ad2fae |
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