Synchrotron and Inverse Compton Variability in the BL Lacertae object S5 0716+714
/ Authors
P. Giommi, E. Massaro, L. Chiappetti, E. Ferrara, G. Ghisellini, M. Jang, M. Maesano, H. R. Miller, F. Montagni, R. Nesci
and 7 more authors
P. Padovani, E. Perlman, C. Raiteri, S. Sclavi, G. Tagliaferri, G. Tosti, M. Villata
/ Abstract
We report intensity variations of different spectral components in the BL Lac object S5 0716+714 detected during coordinated BeppoSAX and optical observations in 1996 and 1998. The transition between synchrotron and inverse Compton emission has been clearly detected as sharp X-ray spectral breaks at around 2-3 keV on both occasions. Correlated optical and soft X-ray variability was found during the second BeppoSAX pointing when intensive optical monitoring could be arranged. The hard (Compton) component changed by a factor of 2 between the two observations, but remained stable within each exposure. During events of rapid variability S5 0716+714 showed spectral steepening with intensity, a behaviour rarely observed in BL Lacs. We interpret these findings as the probable consequence of a shift of the synchrotron peak emission from the IR/optical band to higher energies, causing the synchrotron tail to push into the soft X-ray band more and more as the source brightens.
Journal: arXiv: Astrophysics