| Full text | |
| Author(s): |
Total Authors: 3
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| Affiliation: | [1] Univ Sao Paulo, Inst Astron Geofis & Ciencias Atmosfer, Rua Matao 1226, Cidade Univ, BR-05508090 Sao Paulo, SP - Brazil
Total Affiliations: 1
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| Document type: | Journal article |
| Source: | ASTROPHYSICAL JOURNAL; v. 817, n. 2 FEB 1 2016. |
| Web of Science Citations: | 3 |
| Abstract | |
We analyze an optical data cube of the nuclear region of NGC 3621, taken with the integral field unit of the Gemini Multi-object Spectrograph. We found that the previously detected central line emission in this galaxy actually comes from a blob, located at a projected distance of 2.'' 14 +/- 0.'' 08 (70.1 +/- 2.6 pc) from the stellar nucleus. Only diffuse emission was detected in the rest of the field of view, with a deficit of emission at the position of the stellar nucleus. Diagnostic diagram analysis reveals that the off-centered emitting blob has a Seyfert 2 spectrum. We propose that the line-emitting blob may be a ``fossil{''} emission-line region or a light ``echo{''} from an active galactic nucleus (AGN), which was significantly brighter in the past. Our estimates indicate that the bolometric luminosity of the AGN must have decreased by a factor of similar to 13-500 during the past similar to 230 yr. A second scenario to explain the morphology of the line-emitting areas in the nuclear region of NGC 3621 involves no decrease of the AGN bolometric luminosity and establishes that the AGN is highly obscured toward the observer but not toward the line-emitting blob. The third scenario proposed here assumes that the off-centered line-emitting blob is a recoiling supermassive black hole, after the coalescence of two black holes. Finally, an additional hypothesis is that the central X-ray source is not an AGN, but an X-ray binary. This idea is consistent with all the scenarios we proposed. (AU) | |
| FAPESP's process: | 11/51680-6 - Exploring the universe: from the galaxies formation to Earth-like planets with the Giant Magellan Telescope |
| Grantee: | Laerte Sodré Junior |
| Support Opportunities: | Special Projects |
| FAPESP's process: | 12/02268-8 - Galactic nuclei in the local universe: supermassive black holes and stellar archeology of galaxies of high and low masses |
| Grantee: | Roberto Bertoldo Menezes |
| Support Opportunities: | Scholarships in Brazil - Post-Doctoral |