Sgr B2 hard X-ray emission with INTEGRAL after 2009: still detectable?
| Autor: | E. V. Kuznetsova, Alexander A. Lutovinov, Maïca Clavel, Roman Krivonos |
|---|---|
| Rok vydání: | 2021 |
| Předmět: |
Physics
High Energy Astrophysical Phenomena (astro-ph.HE) Supermassive black hole Molecular cloud Astrophysics::High Energy Astrophysical Phenomena Continuum (design consultancy) FOS: Physical sciences Astronomy and Astrophysics Cosmic ray Astrophysics Astrophysics::Cosmology and Extragalactic Astrophysics Light curve law.invention Space and Planetary Science law Observatory Astrophysics - High Energy Astrophysical Phenomena Astrophysics::Galaxy Astrophysics Line (formation) Flare |
| DOI: | 10.48550/arxiv.2110.07401 |
| Popis: | Molecular cloud Sgr B2 is a natural Compton mirror in the Central Molecular Zone. An observed fading of the Sgr B2 X-ray emission in continuum and Fe K$\alpha$ 6.4 keV line indicates, as believed, a past X-ray flare activity of the supermassive black hole Sgr A$^{\star}$. The Sgr B2 was investigated by the INTEGRAL observatory at hard X-rays in 2003-2009, showing a clear decay of its hard X-ray emission. In this work, we present a long-term time evolution of the Sgr B2 hard X-ray continuum after 2009, associated with the hard X-ray source IGR J17475-2822 as observed by INTEGRAL. The 30-80 keV sky maps, obtained in 2009-2019, demonstrate a significant excess spatially consistent with IGR J17475-2822. The observed 2003-2019 light curve of IGR J17475-2822 is characterized by a linear decrease by a factor of $\sim2$ until 2011, after which it reaches a constant level of $\sim1$ mCrab. The source spectrum above 17 keV is consistent with a power-law model with $\Gamma=1.4$ and a high-energy cut-off at $\sim43$ keV. The Sgr B2 residual emission after $\sim2011$ shows a good correspondence with models of the X-ray emission due to the irradiation of the molecular gas by hard X-rays and low-energy cosmic ray ions. We discuss the possible origin of the residual Sgr B2 emission after 2011 within these models, including theoretically predicted multiply-scattered emission. Comment: 9 pages, 11 figures, 2 tables. Accepted to MNRAS |
| Databáze: | OpenAIRE |
| Externí odkaz: |
|