Sign on

SAO/NASA ADS Astronomy Abstract Service

· Find Similar Abstracts (with default settings below)
· Electronic Refereed Journal Article (HTML)
· Full Refereed Journal Article (PDF/Postscript)
· arXiv e-print (arXiv:0705.0238)
· On-line Data
· References in the article
· Citations to the Article (18) (Citation History)
· Refereed Citations to the Article
· SIMBAD Objects (2)
· Also-Read Articles (Reads History)
·
· Translate This Page
Title:
General Relativistic Flux Modulations from Disk Instabilities in Sagittarius A*
Authors:
Falanga, Maurizio; Melia, Fulvio; Tagger, Michel; Goldwurm, Andrea; Bélanger, Guillaume
Affiliation:
AA(CEA Saclay, DSM/DAPNIA/Service d'Astrophysique, 91191 Gif-sur-Yvette, France; .; AIM-Unité Mixte de Recherche CEA, CNRS, Université Paris VII, UMR 7158, F-91191 Gif-sur-Yvette, France.), AB(Physics Department and Steward Observatory, The University of Arizona, Tucson, AZ 85721.; Sir Thomas Lyle Fellow and Miegunyah Fellow.), AC(CEA Saclay, DSM/DAPNIA/Service d'Astrophysique, 91191 Gif-sur-Yvette, France; .; Université Paris VII Denis Diderot et Observatoire de Paris, Laboratoire APC, Paris, France.), AD(CEA Saclay, DSM/DAPNIA/Service d'Astrophysique, 91191 Gif-sur-Yvette, France; .; Université Paris VII Denis Diderot et Observatoire de Paris, Laboratoire APC, Paris, France.), AE(ESA/ESAC, 28080 Madrid, Spain.)
Publication:
The Astrophysical Journal, Volume 662, Issue 1, pp. L15-L18. (ApJL Homepage)
Publication Date:
06/2007
Origin:
UCP
ApJ Keywords:
Accretion, Accretion Disks, Black Hole Physics, Galaxy: Center, Instabilities, Magnetohydrodynamics: MHD, Relativity
DOI:
10.1086/519278
Bibliographic Code:
2007ApJ...662L..15F

Abstract

Near-IR and X-ray flares have been detected from the supermassive black hole Sgr A* at the center of our Galaxy with a (quasi-)period of ~17-20 minutes, suggesting an emission region only a few Schwarzschild radii above the event horizon. The latest X-ray flare, detected with XMM-Newton, is notable for its detailed light curve, yielding not only the highest quality period thus far, but also important structure reflecting the geometry of the emitting region. Recent MHD simulations of Sgr A*'s disk have demonstrated the growth of a Rossby wave instability that enhances the accretion rate for several hours, possibly accounting for the observed flares. In this Letter, we carry out ray-tracing calculations in a Schwarzschild metric to determine as accurately as possible the light curve produced by general relativistic effects during such a disruption. We find that the Rossby wave-induced spiral pattern in the disk is an excellent fit to the data, implying a disk inclination angle of ~77°. Note, however, that if this association is correct, the observed period is not due to the underlying Keplerian motion but rather to the pattern speed. The favorable comparison between the observed and simulated light curves provides important additional evidence that the flares are produced in Sgr A*'s inner disk.
Bibtex entry for this abstract   Preferred format for this abstract (see Preferences)
   

Find Similar Abstracts:

Use: Authors
Title
Keywords (in text query field)
Abstract Text
Return: Query Results Return    items starting with number
Query Form
Database: Astronomy
Physics
arXiv e-prints