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Quasi Periodic Oscillations in Blazars

Gupta, Alok C.

Here we report our recent discoveries of Quasi-Periodic Oscillations (QPOs) in blazars time series data in X-ray and optical electromagnetic bands. Any such detection can give important clue of the location and nature of the processes of emission mechanism. In the case of radio-quiet AGN, the detected QPOs are very likely to be associated with the…

X-ray Flares Observed from Six Young Stars Located in the Region of Star Clusters NGC 869 and IC 2602

Pandey, J. C.; Singh, K. P.; Kumar, Brijesh +2 more

We present, for the first time, an analysis of seven intense X-ray flares observed from six stars (LAV 796, LAV 1174, SHM2002 3734, 2MASS 02191082+5707324, V553 Car, V557 Car). These stars are located in the region of young open star clusters NGC 869 and IC 2602. These flares detected in the XMM-Newton data show a rapid rise (10–40 min) and a slow…

Orbital Signatures from Observed Light Curves of Blazars

Mangalam, A.; Mohan, P.

Variability in active galactic nuclei is observed in UV to X-ray emission based light curves. This could be attributed to orbital signatures of the plasma that constitutes the accretion flow on the putative disk or in the developing jet close to the inner region of the central black hole. We discuss some theoretical models based on this view. Thes…

Chandra and XMM–Newton Observations of H₂O Maser Galaxy Mrk 348

Wang, J.; Zhang, J. S.; Guo, Q.

For H ₂O megamaser galaxy Mrk 348, Chandra and XMM–Newton data are analysed. The nuclear fitting results of XMM–Newton data suggest the possible existence of a heavily obscured AGN. But the nuclear spectrum extracted from Chandra cannot be well fitted by the best fitting model for XMM–Newton. Further optimal fitting and discussions are …