Volume 629, September 2019
|Number of page(s)||9|
|Published online||04 September 2019|
The coronal temperature of NGC 4388 and NGC 2110 measured with INTEGRAL⋆
INAF-Osservatorio di astrofisica e scienza dello spazio di Bologna, Via Piero Gobetti 93/3, 40129 Bologna, Italy
2 INAF-Istituto di Astrofisica e Planetologia Spaziali, via Fosso del Cavaliere, 00133 Roma, Italy
3 School of Physics and Astronomy, University of Southampton, SO17 1BJ Southampton, UK
Accepted: 2 August 2019
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.
Key words: galaxies: active / galaxies: Seyfert / X-rays: galaxies / X-rays: individuals: NGC 4388 / X-rays: individuals: NGC 2110
The reduced spectra (FITS files) are only available at the CDS via anonymous ftp to cdsarc.u-strasbg.fr (22.214.171.124) or via http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/629/A54
© ESO 2019
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