The Great Slump: Mrk926 reveals discrete and varying Balmer line satellite components during a drastic phase of decline
| Autor: | Stephen E. Rafter, Rolf Chini, Ehud Behar, Bjoern Mueller, Claas Schumacher, Wolfram Kollatschny, Keith Horne, Martin Haas, Shai Kaspi, Doron Chelouche, M. W. Ochmann, Malte A. Probst |
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| Přispěvatelé: | Science & Technology Facilities Council, University of St Andrews. School of Physics and Astronomy, University of St Andrews. St Andrews Centre for Exoplanet Science |
| Rok vydání: | 2021 |
| Předmět: |
Physics
MCC Seyfert [Galaxies] active [Galaxies] Phase (waves) NDAS Balmer series FOS: Physical sciences Astronomy and Astrophysics Astrophysics Astrophysics - Astrophysics of Galaxies Slump symbols.namesake individual: Mrk926 [Galaxies] emission lines [Quasars] QC Physics Space and Planetary Science nuclei [Galaxies] Astrophysics of Galaxies (astro-ph.GA) symbols QB Astronomy Satellite QC Line (formation) QB |
| DOI: | 10.48550/arxiv.2110.10051 |
| Popis: | Mrk926 is known to be a highly variable AGN with very broad line profiles. We studied the continuum and line profile variations of this object with high temporal resolution in order to determine its broad-line region structure and to derive its BH mass. We carried out a high-cadence spectroscopic variability campaign of Mrk926 with the 10m HET telescope, aided by photometric V-band data taken at the Wise Observatory, over a period of about five months. We extracted spectroscopic continuum and line light curves, and computed CCFs as well as velocity-resolved CCFs with respect to the combined continuum V-band light curve. The continuum luminosity of Mrk926 showed a drastic decrease during our campaign: it dropped to less than 50% of its original value within only 2.5 months. The spectra show complex and very broad Balmer line profiles, including outer Balmer satellites ranging from +-5000 to +-13,000 kms-1. The Ha, Hb, and HeI5876 line light curves are delayed relative to the continuum light curve. The Ha and Hb lines show two velocity-delay structures in the central part of their line profile (within +- 5000 kms-1), at ~10 and ~57 ld and at ~5 and ~48 ld, respectively. These structures might be interpreted as the signature of a line-emitting ring, inclined by ~50 deg to the line of sight and orbiting the BH at radii, R, of 33.5 and 26.5 ld. We determined continuum luminosities, log(lambda\,L_(lambda)/erg s-1), of 43.68 to 44.13, which are in good agreement with the established R_(BLR)-L_(AGN) relation. We derive a black hole mass of 1.1 +- 0.2 * 10^8 M_solar; this indicates a low Eddington ratio, which decreased from 8 to 3 percent during our campaign. The Balmer satellite components show a response to the continuum variations on the order of only 3-5 days. We attribute this to the central line segment and the Balmer satellites having different, spatially distinct regions of origin. Comment: 23 pages, 14 figures, published in Astronomy & Astrophysics |
| Databáze: | OpenAIRE |
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