The inner flow geometry in MAXI J1820+070 during hard and hard-intermediate states
| Autor: | B. De Marco, Gabriele Ponti, Tomaso Belloni, G. Migliori, Andrzej A. Zdziarski, Marta A. Dziełak, Eleonora Veronica Lai, A. Segovia Otero |
|---|---|
| Přispěvatelé: | Universitat Politècnica de Catalunya. Departament de Física |
| Jazyk: | angličtina |
| Rok vydání: | 2021 |
| Předmět: |
individuals: MAXI J1820+070 [X-rays]
Accretion Astrophysics::High Energy Astrophysical Phenomena FOS: Physical sciences Geometry Context (language use) Astrophysics 01 natural sciences Spectral line 0103 physical sciences 010303 astronomy & astrophysics Physics High Energy Astrophysical Phenomena (astro-ph.HE) Accretion (meteorology) 010308 nuclear & particles physics X-Rays Astronomy and Astrophysics Radius Covariance Corona Wavelength Amplitude 13. Climate action Space and Planetary Science Física::Astronomia i astrofísica [Àrees temàtiques de la UPC] Accretion disks binaries [X-rays] Raigs X Astrophysics - High Energy Astrophysical Phenomena |
| Zdroj: | UPCommons. Portal del coneixement obert de la UPC Universitat Politècnica de Catalunya (UPC) Astronomy & Astrophysics |
| DOI: | 10.1051/0004-6361/202140567 |
| Popis: | [Abridged] Context: We present a systematic X-ray spectral-timing study of the recently discovered, exceptionally bright black hole X-ray binary system MAXI J1820+070. Our analysis focuses on the first part of the 2018 outburst, covering the rise throughout the hard state, the bright hard and hard-intermediate states, and the transition to the soft-intermediate state. Aims: We address the issue of constraining the geometry of the innermost accretion flow and its evolution throughout an outburst. Methods: We employed two independent X-ray spectral-timing methods applied to the NICER data of MAXI J1820+070. We first identified and tracked the evolution of a characteristic frequency of soft X-ray reverberation lags. Then, we studied the spectral evolution of the quasi-thermal component responsible for the observed thermal reverberation lags. Results: The frequency of thermal reverberation lags steadily increases throughout most of the outburst, implying that the relative distance between the X-ray source and the disc decreases as the source softens. However, near transition this evolution breaks, showing a sudden increase (decrease) of lag amplitude (frequency). The temperature of the quasi-thermal component in covariance spectra consistently increases throughout all the analysed observations. Conclusions: The behaviour of thermal reverberation lags near transition might be related to the relativistic plasma ejections detected at radio wavelengths, suggesting a causal connection between the two phenomena. Throughout most of the hard and hard-intermediate states the disc is consistent with being truncated (with an inner radius $R_{\rm in}>\sim 10 R_{\rm g}$), reaching close to the innermost stable circular orbit only near transition. Accepted for publication in Astronomy & Astrophysics, matches published version |
| Databáze: | OpenAIRE |
| Externí odkaz: |
|