Examinando por Autor "Proga, D."

Mostrando 1 - 2 de 2

Acceso Abierto
A global view of the inner accretion and ejection flow around super massive black holes Radiation-driven accretion disk winds in a physical context
(EDP Sciences, 2019-09-26) Giustini, M.; Proga, D.; Ministerio de Economía y Competitividad (MINECO); National Aeronautics and Space Administration (NASA); Giustini, M. [0000-0002-1329-658X]; Unidad de Excelencia Científica María de Maeztu Centro de Astrobiología del Instituto Nacional de Técnica Aeroespacial y CSIC, MDM-2017-0737
Context. Understanding the physics and geometry of accretion and ejection around super massive black holes (SMBHs) is important to understand the evolution of active galactic nuclei (AGN) and therefore of the large scale structures of the Universe. Aims. We aim at providing a simple, coherent, and global view of the sub-parsec accretion and ejection flow in AGN with varying Eddington ratio, ṁ, and black hole mass, MBH. Methods. We made use of theoretical insights, results of numerical simulations, as well as UV and X-ray observations to review the inner regions of AGN by including different accretion and ejection modes, with special emphasis on the role of radiation in driving powerful accretion disk winds from the inner regions around the central SMBH. Results. We propose five ṁ regimes where the physics of the inner accretion and ejection flow around SMBHs is expected to change, and that correspond observationally to quiescent and inactive galaxies; low luminosity AGN (LLAGN); Seyferts and mini-broad absorption line quasars (mini-BAL QSOs); narrow line Seyfert 1 galaxies (NLS1s) and broad absorption line quasars (BAL QSOs); and super-Eddington sources. We include in this scenario radiation-driven disk winds, which are strong in the high ṁ, large MBH regime, and possibly present but likely weak in the moderate ṁ, small MBH regime. Conclusions. A great diversity of the accretion/ejection flows in AGN can be explained to a good degree by varying just two fundamental properties: the Eddington ratio ṁ and the black hole mass MBH, and by the inclusion of accretion disk winds that can naturally be launched by the radiation emitted from luminous accretion disks.
Acceso Abierto
On Synthetic Absorption Line Profiles of Thermally Driven Winds from Active Galactic Nuclei
(IOP Science Publishing, 2021-06-22) Ganguly, S.; Proga, D.; Waters, T.; Dannen, R. C.; Dyda, S.; Giustini, M.; Kallman, T.; Raymond, J.; Miller, Jon; Rodríguez Hidalgo, P.; National Aeronautics and Space Administration (NASA); Comunidad de Madrid; Ganguly, S. [0000-0002-8256-5982]; Proga, D. [0000-0002-6336-5125]; Waters, T. [0000-0002-5205-9472]; Dannen, R. C. [0000-0002-5160-8716]; Dyda, S. [0000-0002-1954-8864]; Giustini, M. [0000-0002-1329-658X]; Kallman, T. [0000-0002-5779-6906]; Raymond, J. [0000-0002-7868-1622]; Miller, J. [0000-0001-6432-7860]; Rodríguez Hidalgo, P. [0000-0003-0677-785X]
The warm absorbers observed in more than half of all nearby active galactic nuclei are tracers of ionized outflows located at parsec-scale distances from the central engine. If the smallest inferred ionization parameters correspond to plasma at a few 104 K, then the gas undergoes a transition from being bound to unbound, provided it is further heated to ∼106 K at larger radii. Dannen et al. recently discovered that, under these circumstances, thermally driven wind solutions are unsteady and even show very dense clumps due to thermal instability. To explore the observational consequences of these new wind solutions, we compute line profiles based on the one-dimensional simulations of Dannen et al. We show how the line profiles from even a simple steady-state wind solution depend on the ionization energy (IE) of absorbing ions, which is a reflection of the wind ionization stratification. To organize the diversity of the line shapes, we group them into four categories: weak Gaussians, saturated boxy profiles with and without an extended blue wing, and broad weak profiles. The lines with profiles in the last two categories are produced by ions with the highest IE that probe the fastest regions. Their maximum blueshifts agree with the highest flow velocities in thermally unstable models, both steady-state and clumpy versions. In contrast, the maximum blueshifts of the highest-IE lines in thermally stable models can be less than half of the actual solution velocities. Clumpy solutions can additionally imprint distinguishable absorption troughs at widely separated velocities.