NuSTAR catches the unveiling nucleus of NGC 1068

作者：Marinucci A^*; Bianchi S; Matt G; Alexander D M; Balokovic M; Bauer F E; Brandt W N; Gandhi P; Guainazzi M; Harrison F A; Iwasawa K; Koss M; Madsen K K; Nicastro F; Puccetti S; Ricci C; Stern D; Walton D J

来源：Monthly Notices of the Royal Astronomical Society, 2016, 456(1): L94-L98.

DOI：10.1093/mnrasl/slv178

• galaxies: active
• galaxies: individual: NGC 1068
• galaxies: Seyfert

We present a NuSTAR and XMM-Newton monitoring campaign in 2014/2015 of the Compton-thick Seyfert 2 galaxy, NGC 1068. During the 2014 August observation, we detect with NuSTAR a flux excess above 20 keV (32 +/- 6 per cent) with respect to the 2012 December observation and to a later observation performed in 2015 February. We do not detect any spectral variation below 10 keV in the XMM-Newton data. The transient excess can be explained by a temporary decrease of the column density of the obscuring material along the line of sight (from N-H similar or equal to 10(25) cm(-2) to N-H = 6.7 +/- 1.0 x 10(24) cm(-2)), which allows us for the first time to unveil the direct nuclear radiation of the buried active galactic nucleus in NGC 1068 and to infer an intrinsic 2-10 keV luminosity L-X = 7(-4)(+7) x 10(43) erg s(-1).

• 出版日期2016-2-11