• SERGIO A. CELLONE

      Articles written in Journal of Astrophysics and Astronomy

    • Optical flux and spectral characterization of the blazar PG 1553 $+$ 113 based on the past 15 years of data

      ADITI AGARWAL B. MIHOV I. ANDRUCHOW SERGIO A. CELLONE G. C. ANUPAMA V. AGRAWAL S. ZOLA AYKUT OZDONMEZ ERGUN EGE

      More Details Abstract Fulltext PDF

      We study flux and spectral variability of the high energy peaked TeV blazar PG 1553 $+$ 113 on diverse timescales using the data collected from 2005 to 2019 which also includes the intensive intra-night monitoring of the target. Additionally, we recorded the brightest flare of the blazar PG 1553 $+$ 113 during April 2019 when the source attained an $R$-band magnitude of 13.2. Analyzing the spectral evolution of the source during the flare gave a clockwise spectral hysteresis loop and a time lag with $V$-band variations leading to the $R$-band ones. Various statistical tests, fitting procedures and cross-correlation techniques are applied to search for periodicity and examine the color-magnitude relationship. We find a median period of ($2.21 \pm 0.04$) years along with the secondary period of about 210 days. Finally, we briefly discuss variousphysical mechanisms which are capable of explaining our findings.

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