Issue |
A&A
Volume 613, May 2018
|
|
---|---|---|
Article Number | A48 | |
Number of page(s) | 11 | |
Section | Astrophysical processes | |
DOI | https://doi.org/10.1051/0004-6361/201732235 | |
Published online | 30 May 2018 |
NGC 4051: Black hole mass and photon index-mass accretion rate correlation
1
LAPTh, Université Savoie-Mont-Blanc, CNRS,
B.P. 110,
74941
Annecy-le-Vieux,
France
2
Lomonosov Moscow State University/Sternberg Astronomical Institute, Universitetsky Prospect 13,
Moscow
119992,
Russia
e-mail: seif@sai.msu.ru
3
George Mason University, College of Science, 4400 University Drive,
Fairfax,
VA 22030,
USA
e-mail: achekhtm@gmu.edu
4
Dipartimento di Fisica, Università di Ferrara,
Via Saragat 1,
44122
Ferrara,
Italy
e-mail: titarchuk@fe.infn.it
Received:
4
November
2017
Accepted:
28
January
2018
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.
Key words: accretion, accretion disks / black hole physics / radiation mechanisms: non-thermal / stars: black holes
© ESO 2018
Current usage metrics show cumulative count of Article Views (full-text article views including HTML views, PDF and ePub downloads, according to the available data) and Abstracts Views on Vision4Press platform.
Data correspond to usage on the plateform after 2015. The current usage metrics is available 48-96 hours after online publication and is updated daily on week days.
Initial download of the metrics may take a while.