| Name: NIRAJ KUMAR SAHU |
| Affiliation: Indian Institute of Science Education and Research Mohali (IISER Mohali) |
| Conference ID: ASI2026_54 |
| Title: Simultaneous Optical-to-X-ray spectral view of VHE FSRQs with Swift. |
| Abstract Type: Poster |
| Abstract Category: High Energy Phenomena, Fundamental Physics and Astronomy |
| Author(s) and Co-Author(s) with Affiliation: Niraj Kumar Sahu(Indian Institute of Science Education and Research (IISER) Mohali, Mohali-140306, India.), Dr. Pankaj Kushwaha(Indian Institute of Science Education and Research (IISER) Mohali, Mohali-140306, India.) |
| Abstract: A special type of Active Galactic Nuclei (AGNs; the central part of the galaxies) called Blazars are jetted AGNs with bipolar relativistic jets pointing to the line of sight at a small angle (≤ 15°). Flat-Spectrum Radio Quasars (FSRQs) are a subtype of blazars, and their optical spectra are characterized by prominent broad emission lines. They are the most powerful and energetic persistent MeV-GeV sources, but to date, only 11 have been detected at very high-energy gamma-ray (VHE; E > 100 GeV) levels. In SED modeling, the explanation of the VHE spectrum often requires an optical-UV synchrotron component extending into the X-ray, which, in general, is explained by Synchrotron-Self-Compton (SSC). Thus, simultaneous joint optical-to-X-ray spectral variability holds a potential clue. Also, X-rays have been argued to be the best band for searching for hadronic emission.
To understand and explore this further, we performed a systematic spectro-temporal analysis of VHE-detected FSRQs using the Swift Observatory's Ultraviolet/Optical Telescope (UVOT) and X-ray Telescope (XRT) observations to probe UV/Optical and X-ray spectral and temporal variability and explore their potential links with VHE activity. Through this work, we are investigating the behavior of VHE-detected FSRQs during VHE-active states and relating them to their non-VHE states. One of the key outcomes is that, by adding UV-optical data, we are able to explain the altered X-ray spectral properties in several VHE-detected FSRQs. We discuss the results on the temporal and spectral properties of VHE-detected FSRQs and their possible implications for understanding the dominant/current emission mechanisms in these extreme jet environments and connection to VHE activity.
|
