| Autor: |
Xiaofeng Li, Jun Yang, Xiaopeng Cheng, Mai Liao, Xiaoyu Hong, Liming Dou, Tianle Zhao, Zhongying Fan, Fupeng Zhang, Weirong Huang |
| Jazyk: |
angličtina |
| Rok vydání: |
2023 |
| Předmět: |
|
| Zdroj: |
The Astrophysical Journal, Vol 960, Iss 1, p 1 (2023) |
| Druh dokumentu: |
article |
| ISSN: |
1538-4357 |
| DOI: |
10.3847/1538-4357/ad0be6 |
| Popis: |
M60, an elliptical galaxy located 16.5 Mpc away, has an active nucleus with a very low luminosity and an extremely low accretion rate. Its central supermassive black hole (SMBH) has a mass of M _BH ∼ 4.5 × 10 ^9 M _⊙ and a Schwarzschild radius corresponding to R _S ∼ 5.4 μ as. To investigate the nature of its innermost radio nucleus, data from the Very Long Baseline Array (VLBA) at 4.4 and 7.6 GHz were reduced. The VLBA images reveal a compact component with total flux densities of ∼20 mJy at both frequencies, a size of ≤0.27 mas (99.7% confidence level), about 0.022 pc (50 R _S ) at 7.6 GHz, and a brightness temperature of ≥6 × 10 ^9 K. This suggests that the observed centiparsec-scale compact core could be attributed to a nonthermal jet base or an advection-dominated accretion flow (ADAF) with nonthermal electrons. The extremely compact structure also supports the presence of an SMBH in the center. Our results indicate that M60 is a promising target for broadband very long baseline interferometry observations at millimeter wavelengths to probe ADAF scenarios and tightly constrain the potential photon ring (about 28 μ as) around its SMBH. |
| Databáze: |
Directory of Open Access Journals |
| Externí odkaz: |
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