2024/10/31 by J. Majumdar, Majumdar, Joysankar, Maurya, Sakshi +2
Physics and Astronomy · #Astrophysics and Cosmic Phenomena #Astrophysics of Galaxies (astro-ph.GA) #FOS: Physical sciences #Gamma-ray bursts and supernovae #High Energy Astrophysical Phenomena (astro-ph.HE) #Solar and Space Plasma Dynamics
paper · pdf · doi:10.48550/arxiv.2410.23778
openalex publication_date 2024/10/31 · openalex created_date 2024/11/14 · openalex updated_date 2026/07/30
In October 2024, The object BL Lac experienced a brightest flaring event in gamma-ray (>100 MeV) with a historical γ-ray flux of ∼10-5 erg cm-2 s-1. Soon after the event was followed across the waveband and in X-ray (0.3-10 keV) it was also found to be flaring with the maximum flux achieved during this event as 8.30×10-11 erg cm-2 s-1. The high gamma-ray significance enables us to probe the shortest time scale variability possible and for that, we produced the orbital binned light curve, 5 minutes binned light curve, and the 2 minutes binned light curve. A clear variation is seen in the 5-minute light curve and is fitted with the sum of exponentials to derive the rise and decay time scale which ranges between 3 to 12 minutes. The fastest variability time is also estimated to be an order of 1 minute from 2 minute. The estimated size of the emission region is very small (1013 cm) compared to the size of the black hole event horizon. The location of the emission region is estimated to be very close to the supermassive black hole (1014 cm) and much inside the BLR (0.1 pc). We discussed the possible way to explain this fast-flux variability in BL Lac.