Broad-band spectral study of X-ray transient MAXI J1820+070 using Swift/XRT and NuSTAR
| Autor: | Bharali, Priya, Chauhan, Jaiverdhan, Boruah, Kalyanee |
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| Rok vydání: | 2019 |
| Předmět: | |
| Druh dokumentu: | Working Paper |
| DOI: | 10.1093/mnras/stz1686 |
| Popis: | We report on a \textit{NuSTAR} and \textit{Swift}/XRT observation of the newly discovered X-ray transient MAXI J1820+070. \textit{Swift}/XRT and \textit{NuSTAR} have concurrently observed the newly detected source on 14 March 2018. We have simultaneously fitted the broad-band spectra obtained from \textit{Swift}/XRT and \textit{NuSTAR}. The observed joint spectra in the energy range 0.6--78.0 keV are well modeled with a weak disk black-body emission, dominant thermal Comptonization and relativistic reflection fraction. We have detected a fluorescent Iron-K$\alpha$ line relativistically broadened, and a Compton hump at $\sim$ 30 keV. We constrain the inner disk radius as well as the disk inclination angle and their values are found to be 4.1$^{+0.8}_{-0.6}$ R$_{ISCO}$ (where R$_{ISCO}\equiv$ radius of the innermost stable circular orbit) or 5.1$^{+1.0}_{-0.7}$ r$_{g}$ (where r$_{g}\equiv$ gravitational radius) and 29.8$^{+3.0}_{-2.7}$ $^\circ$ respectively. The best fit broad-band spectra suggest that the source was in the hard state and evolving. The source emission is best described by weak thermal emission along with strong thermal Comptonization from a relatively cold, optically thick, geometrically thin and ionized accretion disk. X-ray spectral modeling helps us to understand the accretion and ejection properties in the vicinity of the compact object. Comment: 07 pages, 05 figures and 02 tables, Accepted for publication by Monthly Notices of the Royal Astronomical Society |
| Databáze: | arXiv |
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