Zobrazeno 1 - 10
of 536
pro vyhledávání: '"Gaskell C"'
Autor:
Falcão, Anna Trindade, Kraemer, S. B., Fischer, T. C., Schmitt, H. R., Feuillet, L., Crenshaw, D. M., Revalski, M., Maksym, W. P., Vestergaard, M., Elvis, M., Gaskell, C. M., Ho, L. C., Netzer, H., Storchi-Bergmann, T., Turner, T. J., Ward, M. J.
We use the Hubble Space Telescope to analyse the extended [O III] 5007A emission in seven bright radio-quiet type 1 quasars (QSO1s), focusing on the morphology and physical conditions of their extended Narrow-Line Regions (NLRs). We find NLRs extendi
Externí odkaz:
http://arxiv.org/abs/2410.16053
Autor:
Oknyansky, V. L., Gaskell, C. M.
We show that, contrary to simple predictions, most AGNs show at best only a small increase of lags with increasing wavelength in the J, H, K, and L bands . We suggest that a possible cause of this near simultaneity of the variability from the near-IR
Externí odkaz:
http://arxiv.org/abs/2305.17781
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
Autor:
Falcão, Anna Trindade, Kraemer, S. B., Fischer, T. C., Crenshaw, D. M., Revalski, M., Schmitt, H. R., Maksym, W. P., Vestergaard, M., Elvis, M., Gaskell, C. M., Hamann, F., Ho, L. C., Hutchings, J., Mushotzky, R., Netzer, H., Storchi-Bergmann, T., Turner, T. J., Ward, M. J.
We present a dynamical study of the narrow-line regions in two nearby QSO2s. We construct dynamical models based on detailed photoionization models of the emission-line gas, including the effects of internal dust, to apply to observations of large-sc
Externí odkaz:
http://arxiv.org/abs/2105.12188
Autor:
Falcao, Anna Trindade, Kraemer, S. B., Fischer, T. C., Crenshaw, D. M., Revalski, M., Schmitt, H. R., Vestergaard, M., Elvis, M., Gaskell, C. M., Hamann, F., Ho, L. C., Hutchings, J., Mushotzky, R., Netzer, H., Storchi-Bergmann, T., Turner, T. J., Ward, M. J.
We use Hubble Space Telescope (HST)/ Space Telescope Imaging Spectrograph (STIS) long-slit G430M and G750M spectra to analyse the extended [O~III] 5007A emission in a sample of twelve nearby (z < 0.12) luminous (L_bol > 1.6 x 10^45 erg s^-1) QSO2s. T
Externí odkaz:
http://arxiv.org/abs/2010.08050
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
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