2017/10/05 by Main Pal, G. C. Dewangan, Gulab C. Dewangan +4 · 8 citations
Physics and Astronomy · #Accretion (finance) #Amplitude #Astronomy #Astrophysical Phenomena and Observations #Astrophysics #Astrophysics and Cosmic Phenomena #Corona (planetary geology) #Emission spectrum #Flux (metallurgy) #Galaxies: Formation, Evolution, Phenomena #Galaxy #Light curve #Optics #Physics #Reflection (computer programming) #Spectral line #astro-ph.HE
paper · pdf · doi:10.1093/mnras/stx2608
published in Monthly Notices of the Royal Astronomical Society 473(3), 3584-3597 (Oxford University Press) · 15 pages, 10 figures, accepted for publication in MNRAS
arxiv created 2017/10/05 · openalex publication_date 2017/10/06 · arxiv updated 2018/01/08 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/05
We present detailed broad-band UV/optical to X-ray spectral variability of the Seyfert 1 galaxy 1H 0419–577 using six XMM–Newton observations performed during 2002–2003. These observations covered a large amplitude variability event in which the soft X-ray (0.3–2 keV) count rate increased by a factor of ∼4 in six months. The X-ray spectra during the variability are well described by a model consisting of a primary power law, blurred and distant reflection. The 2–10 keV power-law flux varied by a factor of ∼7 while the 0.3–2 keV soft X-ray excess flux derived from the blurred reflection component varied only by a factor of ∼2. The variability event was also observed in the optical and UV bands but the variability amplitudes were only at the 6–10 per cent level. The variations in the optical and UV bands appear to follow the variations in the X-ray band. During the rising phase, the optical bands appear to lag behind the UV band but during the declining phase, the optical bands appear to lead the UV band. Such behaviour is not expected in the reprocessing models where the optical/UV emission is the result of reprocessing of X-ray emission in the accretion disc. The delayed contribution of the broad emission lines in the UV band or the changes in the accretion disc/corona geometry combined with X-ray reprocessing may give rise to the observed behaviour of the variations.