| Autor: |
Seifina, Elena, Chekhtman, Alexandre, Titarchuk, Lev |
| Předmět: |
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| Zdroj: |
Astronomy & Astrophysics / Astronomie et Astrophysique; May2018, Vol. 613, p1-N.PAG, 11p |
| Abstrakt: |
We present a discovery of the correlation between the X-ray spectral (photon) index and mass accretion rate observed in an active galactic nucleus, NGC 4051. We analyzed spectral transition episodes observed in NGC 4051 using XMM-Newton, Suzaku and RXTE. We applied a scaling technique for a black hole (BH) mass evaluation which uses a correlation between the photon index and normalization of the seed (disk) component, which is proportional to a mass accretion rate.We developed an analytical model that shows the spectral (photon) index of the BH emergent spectrum undergoes an evolution from lower to higher values depending on a mass accretion rate in the accretion disk. We considered Cygnus X-1 and GRO J1550-564 as reference sources for which distances, inclination angles and the BH masses are evaluated by dynamical measurements. Application of the scaling technique for the photon index-mass accretion rate correlation provides an estimate of the black hole mass in NGC 4051 to be more than 6 × 105 solar masses. [ABSTRACT FROM AUTHOR] |
| Databáze: |
Complementary Index |
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