1. Investigating the nature and properties of MAXI J1810−222 with radio and X-ray observations
- Author
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T D Russell, M Del Santo, A Marino, A Segreto, S E Motta, A Bahramian, S Corbel, A D’Aì, T Di Salvo, J C A Miller-Jones, C Pinto, F Pintore, A Tzioumis, European Commission, Agencia Estatal de Investigación (España), Astrophysique Interprétation Modélisation (AIM (UMR7158 / UMR_E_9005 / UM_112)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS), Unité Scientifique de la Station de Nançay (USN), Observatoire des Sciences de l'Univers en région Centre (OSUC), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université d'Orléans (UO)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, and Université Paris sciences et lettres (PSL)-Université d'Orléans (UO)-Centre National de la Recherche Scientifique (CNRS)
- Subjects
High Energy Astrophysical Phenomena (astro-ph.HE) ,Accretion ,individual: MAXI J1810-222 [X-rays] ,Astrophysics::High Energy Astrophysical Phenomena ,FOS: Physical sciences ,transients [Radio continuum] ,neutron [Stars] ,Astronomy and Astrophysics ,Astrophysics::Cosmology and Extragalactic Astrophysics ,Black hole physics ,Stars: neutron ,X-rays:binaries ,X-rays: binaries ,Space and Planetary Science ,Radio continuum: transients ,Astrophysics::Solar and Stellar Astrophysics ,binaries [X-rays] ,X-rays: individual: MAXI J1810−222 ,Astrophysics - High Energy Astrophysical Phenomena ,[PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph] ,Accretion discs ,X-rays: individual: MAXI J1810-222 - Abstract
We present results from radio and X-ray observations of the X-ray transient MAXI J1810-222. The nature of the accretor in this source has not been identified. In this paper, we show results from a quasi-simultaneous radio and X-ray monitoring campaign taken with the Australia Telescope Compact Array (ATCA), the Neil Gehrels Swift observatory X-ray telescope (XRT), and the Swift Burst Alert Telescope (BAT). We also analyse the X-ray temporal behaviour using observations from the Neutron star Interior Composition Explorer (NICER). Results show a seemingly peculiar X-ray spectral evolution of MAXI J1810-222 during this outburst, where the source was initially only detected in the soft X-ray band for the early part of the outburst. Then, ~200 days after MAXI J1810-222 was first detected the hard X-ray emission increased and the source transitioned to a long-lived (~1.5 years) bright, harder X-ray state. After this hard state, MAXI J1810-222 returned back to a softer state, before fading and transitioning again to a harder state and then appearing to follow a more typical outburst decay. From the X-ray spectral and timing properties, and the source's radio behaviour, we argue that the results from this study are most consistent with MAXI J1810-222 being a relatively distant ($\gtrsim$6 kpc) black hole X-ray binary. A sufficiently large distance to source can simply explain the seemingly odd outburst evolution that was observed, where only the brightest portion of the outburst was detectable by the all-sky X-ray telescopes., Comment: 15 pages, 8 figures, 5 tables, accepted for publication in MNRAS
- Published
- 2022