Abstract Details

Name: Prasanta Bera
Affiliation: Research Scholar, IUCAA
Conference ID: ASI2017_835
Title : Spectral and timing properties of the magnetic CVs
Authors and Co-Authors : Dipankar Bhattacharya(IUCAA)
Abstract Type : Oral
Abstract Category : Stars,ISM and the Galaxy
Abstract : White dwarfs in a binary system can accrete matter from the companion star which loses matter due to either Roche lobe overflow or stellar wind. In general, the accreted matter forms a disk before falling on the white dwarf surface. In case of a magnetized white dwarf in such a system, the ionized accreted matter follows the magnetic field lines when the magnetic stress dominates the flow in the accretion disk. The field strength of the white dwarf decides the region where the matter starts to follow the field lines. This accreted matter flows with a very high speed and forms a dynamical shock before coming to the rest on the white dwarf surface near the magnetic pole. The kinetic energy of the accreted matter is converted to the radiation in the shock region and emits significant amount in the soft X-ray region. Various observations suggest the presence of temporal variability of the emitted optical radiation from a few of such objects. 1-d accretion column with radiation cooling (bremsstrahlung and cyclotron) effects is modeled to study the temporal characteristics. For a stronger magnetic field, a significant amount of optical radiation is generated by the cyclotron process. The quasi-periodic oscillation behavior of the shocked structure due to the bremsstrahlung process is suppressed in the presence of this cyclotron emission.