380 citations · 1.3k across the 15 of their papers we have counts for
4 papers · 1 filter
Rapid N_H changes in NGC 4151
S. Puccetti, F. Fiore, G. Risaliti +4
We have analyzed the two longest (elapsed time > 3 days) BeppoSAX observations of the X-ray brightest Seyfert galaxy, NGC 4151, to search for spectral variability on time-scales fr…
The double AGN in NGC 6240 revealed through 3-5 micron spectroscopy
G. Risaliti, E. Sani, R. Maiolino +7
We present 3-5 micron spectroscopy of the interacting system NGC 6240, showing the presence of two active galactic nuclei. The brightest (southern) nucleus shows up with a starburs…
Rapid N_H Changes in NGC 4151
S. Puccetti, G. Risaliti, F. Fiore +4
We have analyzed two long BeppoSAX observations of the bright Seyfert galaxy NGC 4151, searching for short timescale (10-200 ksec) X-ray spectral variability. The light curve of a…
The variability of the Seyfert galaxy NGC 2992: the case for a revived AGN
R. Gilli, R. Maiolino, A. Marconi +4
We report the transition to an active state of the nucleus in the Seyfert 1.9 galaxy NGC 2992, discovered by means of new hard X-ray data. While the 2-10 keV flux declined by a fac…