Zobrazeno 1 - 10
of 160
pro vyhledávání: '"Gaskell C. Martin"'
Autor:
Gaskell C. Martin
Publikováno v:
Open Astronomy, Vol 20, Iss 3, Pp 392-399 (2011)
The general picture of how thermal AGNs work has become clearer in recent years but major observational puzzles threaten to undermine this picture. These puzzles include AGNs with extremely asymmetric emission line profiles, inconsistent multi-wavele
Externí odkaz:
https://doaj.org/article/f92c00c7050b4137945f8647e297a4d6
We use seven different methods to estimate broad-line and continuum reddenings of NGC 5548. We investigate two possible reddening curves considered for active galactic nuclei (AGNs): the mean AGN reddening curve of Gaskell & Benker (2007) which is re
Externí odkaz:
http://arxiv.org/abs/2208.11437
We review problems raised by Fe II emission in AGNs and address the question of its relationship to other broad-line region (BLR) lines. The self-shielding, stratified, BLR model of Gaskell, Klimek & Nazarova (2007; GKN) predicts that Fe II emission
Externí odkaz:
http://arxiv.org/abs/2112.06559
Autor:
Heard, Clio Z. P., Gaskell, C. Martin
We analyze the photometric variability of 4,611 active galactic nuclei (AGNs) from the Sloan Digital Sky Survey Stripe 82. We recover the spectral energy distribution (SED) of the variable flux as a function of wavelength. For rest wavelengths longer
Externí odkaz:
http://arxiv.org/abs/2108.09995
Publikováno v:
Monthly Notices of the Royal Astronomical Society, Volume 493, Issue 1, p.930-939 (2020)
We present a large compilation of reddening estimates from broad-line Balmer decrements for active galactic nuclei (AGNs) with measured X-ray column densities. The median reddening is E(B-V) ~ 0.77 +/- 0.10 for type-1 to type-1.9 AGNs with reported c
Externí odkaz:
http://arxiv.org/abs/2001.08900
Akademický článek
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Publikováno v:
Monthly Notices of the Royal Astronomical Society, Volume 508, Issue 4, pp.6077-6091 (2021)
In the standard AGN reverberation-mapping model, variations in broad-line region (BLR) fluxes are predicted from optical continuum variability (taken as a proxy for the ionizing continuum) convolved with a response function that depends on the geomet
Externí odkaz:
http://arxiv.org/abs/1909.06275
Autor:
Hung, T., Cenko, S. B., Roth, Nathaniel, Gezari, S., Veilleux, S., Van Velzen, Sjoert, Gaskell, C. Martin, Foley, Ryan J., Blagorodnova, N., Yan, Lin, Graham, M. J., Brown, J. S., Siebert, M. R., Frederick, Sara, Ward, Charlotte, Gatkine, Pradip, Gal-yam, Avishay, Yang, Yi, Schulze, S., Dimitriadis, G., Kupfer, Thomas, Shupe, David L., Rusholme, Ben, Masci, Frank J., Riddle, Reed, Soumagnac, Maayane T., Van Roestel, J., Dekany, Richard
We report the discovery of non-stellar hydrogen Balmer and metastable helium absorption lines accompanying a transient, high-velocity (0.05$c$) broad absorption line (BAL) system in the optical spectra of the tidal disruption event (TDE) AT2018zr ($z
Externí odkaz:
http://arxiv.org/abs/1903.05637
Publikováno v:
Proceedings of Science, V.328, N12, 2018
Two major challenges to unification schemes for active galactic nuclei (AGN) are the existence of Narrow-Line Seyfert 1s (NLS1s) and the existence of changing-look (CL) AGNs. AGNs can drastically change their spectral appearance in the optical (chang
Externí odkaz:
http://arxiv.org/abs/1810.08844
The profiles of the broad emission lines of active galactic nuclei (AGNs) and the time delays in their response to changes in the ionizing continuum ("lags") give information about the structure and kinematics of the inner regions of AGNs. Line profi
Externí odkaz:
http://arxiv.org/abs/1704.06455