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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…
Ultraviolet Spectroscopic Study of BY Circini and V 1425 Aquilae from IUE Satellite
Sanad, M. R.
We present the ultraviolet spectra of two classical novae, BY Circini 1995 and V1425 Aquilae 1995, using observations obtained with the International Ultraviolet Explorer (IUE). The outflow velocity of the ionized ejecta was calculated to be 2100–2700 km s‑1 and 1600–1900 km s‑1 (FWHM) for BY Cir and V1425 Aql, respectively. …
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 …