Aims. We aim to measure the physical properties of the hot X-ray corona of two active galactic nuclei, NGC 4388 and NGC 2110. Methods. We analysed the hard X-ray (20-300 keV) INTEGRAL spectrum in conjunction with archival XMM-Newton and NuSTAR data. Results. The X-ray spectrum of both sources is phenomenologically well described by an absorbed cut-off power law. In agreement with previous results, we find no evidence of a Compton reflection component in these sources. We obtain a high-energy cut-off of 200-40+75 keV for NGC 4388 and 320-60+100 keV for NGC 2110. A fit with a thermal Comptonisation model yields a coronal temperature of 80-20+40 keV and 75-15+20 keV, respectively, and an optical depth of approximately two, assuming a spherical geometry. The coronal temperature and luminosity of both sources are consistent with pair production that acts as a thermostat for the thermal plasma. These results emphasise the importance of good signal-to-noise X-ray data above 100 keV to probe the high-energy emission of AGNs.
Ursini, F., Bassani, L., Malizia, A., Bazzano, A., Bird, A.J., Stephen, J.B., et al. (2019). The coronal temperature of NGC 4388 and NGC 2110 measured with INTEGRAL. ASTRONOMY & ASTROPHYSICS, 629, A54 [10.1051/0004-6361/201936273].
The coronal temperature of NGC 4388 and NGC 2110 measured with INTEGRAL
Ursini F.
;
2019-01-01
Abstract
Aims. We aim to measure the physical properties of the hot X-ray corona of two active galactic nuclei, NGC 4388 and NGC 2110. Methods. We analysed the hard X-ray (20-300 keV) INTEGRAL spectrum in conjunction with archival XMM-Newton and NuSTAR data. Results. The X-ray spectrum of both sources is phenomenologically well described by an absorbed cut-off power law. In agreement with previous results, we find no evidence of a Compton reflection component in these sources. We obtain a high-energy cut-off of 200-40+75 keV for NGC 4388 and 320-60+100 keV for NGC 2110. A fit with a thermal Comptonisation model yields a coronal temperature of 80-20+40 keV and 75-15+20 keV, respectively, and an optical depth of approximately two, assuming a spherical geometry. The coronal temperature and luminosity of both sources are consistent with pair production that acts as a thermostat for the thermal plasma. These results emphasise the importance of good signal-to-noise X-ray data above 100 keV to probe the high-energy emission of AGNs.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
