Reexamination of the CO Absorption Line in the M87 Nucleus
We analyzed the archival Atacama Large Millimeter/submillimeter Array data of the nuclear region of M87 and evaluated the molecular gas content from the CO(2–1) absorption line. We found an enigmatic variability in the absorption line depth between two epochs separated by only two months. We reexami...
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IOP Publishing
2025-01-01
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| Online Access: | https://doi.org/10.3847/1538-4357/adf726 |
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| author | Norita Kawanaka Hiroshi Nagai Yutaka Fujita |
| author_facet | Norita Kawanaka Hiroshi Nagai Yutaka Fujita |
| author_sort | Norita Kawanaka |
| collection | DOAJ |
| description | We analyzed the archival Atacama Large Millimeter/submillimeter Array data of the nuclear region of M87 and evaluated the molecular gas content from the CO(2–1) absorption line. We found an enigmatic variability in the absorption line depth between two epochs separated by only two months. We reexamined the data set used in the analysis and found that the bandpass calibration source within the same data set also revealed a similar absorption line structure. Furthermore, we observed a rise in the system noise temperature spectrum. We concluded that the absorption line structure identified in a previous study, and attributed to CO(2–1), does not originate from M87 but instead results from telluric contamination, and that we still have only the upper limit on the molecular gas around the nucleus of M87. |
| format | Article |
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| institution | Kabale University |
| issn | 1538-4357 |
| language | English |
| publishDate | 2025-01-01 |
| publisher | IOP Publishing |
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| series | The Astrophysical Journal |
| spelling | doaj-art-0cc3a5f7c5c448e0a4228f4ccfbda2e62025-08-26T06:17:46ZengIOP PublishingThe Astrophysical Journal1538-43572025-01-0199016610.3847/1538-4357/adf726Reexamination of the CO Absorption Line in the M87 NucleusNorita Kawanaka0https://orcid.org/0000-0001-8181-7511Hiroshi Nagai1https://orcid.org/0000-0003-0292-3645Yutaka Fujita2https://orcid.org/0000-0003-0058-9719National Astronomical Observatory of Japan (NAOJ) , 2-21-1 Osawa, Mitaka, Tokyo 181-8588, Japan; Department of Physics, Graduate School of Science, Tokyo Metropolitan University , 1-1 Minami-Osawa, Hachioji-shi, Tokyo 192-0397, JapanNational Astronomical Observatory of Japan (NAOJ) , 2-21-1 Osawa, Mitaka, Tokyo 181-8588, Japan; The Graduate University for Advanced Studies , SOKENDAI, Osawa 2-21-1, Mitaka, Tokyo 181-8588, JapanDepartment of Physics, Graduate School of Science, Tokyo Metropolitan University , 1-1 Minami-Osawa, Hachioji-shi, Tokyo 192-0397, JapanWe analyzed the archival Atacama Large Millimeter/submillimeter Array data of the nuclear region of M87 and evaluated the molecular gas content from the CO(2–1) absorption line. We found an enigmatic variability in the absorption line depth between two epochs separated by only two months. We reexamined the data set used in the analysis and found that the bandpass calibration source within the same data set also revealed a similar absorption line structure. Furthermore, we observed a rise in the system noise temperature spectrum. We concluded that the absorption line structure identified in a previous study, and attributed to CO(2–1), does not originate from M87 but instead results from telluric contamination, and that we still have only the upper limit on the molecular gas around the nucleus of M87.https://doi.org/10.3847/1538-4357/adf726Elliptical galaxiesActive galactic nucleiBrightest cluster galaxiesInterstellar medium |
| spellingShingle | Norita Kawanaka Hiroshi Nagai Yutaka Fujita Reexamination of the CO Absorption Line in the M87 Nucleus The Astrophysical Journal Elliptical galaxies Active galactic nuclei Brightest cluster galaxies Interstellar medium |
| title | Reexamination of the CO Absorption Line in the M87 Nucleus |
| title_full | Reexamination of the CO Absorption Line in the M87 Nucleus |
| title_fullStr | Reexamination of the CO Absorption Line in the M87 Nucleus |
| title_full_unstemmed | Reexamination of the CO Absorption Line in the M87 Nucleus |
| title_short | Reexamination of the CO Absorption Line in the M87 Nucleus |
| title_sort | reexamination of the co absorption line in the m87 nucleus |
| topic | Elliptical galaxies Active galactic nuclei Brightest cluster galaxies Interstellar medium |
| url | https://doi.org/10.3847/1538-4357/adf726 |
| work_keys_str_mv | AT noritakawanaka reexaminationofthecoabsorptionlineinthem87nucleus AT hiroshinagai reexaminationofthecoabsorptionlineinthem87nucleus AT yutakafujita reexaminationofthecoabsorptionlineinthem87nucleus |