Science-advisor
REGISTER info/FAQ
Login
username
password
     
forgot password?
register here
 
Research articles
  search articles
  reviews guidelines
  reviews
  articles index
My Pages
my alerts
  my messages
  my reviews
  my favorites
 
 
Stat
Members: 3643
Articles: 2'487'895
Articles rated: 2609

29 March 2024
 
  » arxiv » 0907.3786

 Article overview


Simultaneous Multi-Wavelength Observations of Sgr A* during 2007 April 1-11
F. Yusef-Zadeh ; H. Bushouse ; M. Wardle ; C. Heinke ; D. A. Roberts ; C.D. Dowell ; A. Brunthaler ; M. J. Reid ; C. L. Martin ; D. P. Marrone ; D. Porquet ; N. Grosso ; K. Dodds-Eden ; G. C. Bower ; H. Wiesemeyer ; A. Miyazaki ; S. Pal ; S. Gillessen ; A. Goldwurm ; G. Trap ; H. Maness ;
Date 22 Jul 2009
AbstractWe report the detection of variable emission from Sgr A* in almost all wavelength bands (i.e. cm, mm, submm, near-IR and X-rays) during a multi-wavelength observing campaign. Three new moderate flares are detected simultaneously in both near-IR (NIR) and X-ray bands. The ratio of X-ray to NIR flux in the flares is consistent with inverse Compton scattering of NIR photons by submm emitting relativistic particles which follow scaling relations obtained from size measurements of Sgr A*. We also find that the flare statistics in NIR wavelengths is consistent with the probability of flare emission being inversely proportional to the flux. At mm wavelengths, the presence of flare emission at 43 GHz (7mm) using VLBA with milli-arcsecond spatial resolution indicates the first direct evidence that hourly time scale flares are localized within the inner 30x70 Schwarzschild radii of Sgr A*. We also show several cross correlation plots between NIR, mm and submm light curves that collectively demonstrate the presence of time delays between the peaks of emission up to three hours. The evidence for time delays at mm and submm wavelengths are consistent with the source of emission being optically thick initially followed by a transition to an optically thin regime. In particular, there is an intriguing correlation between the optically thin NIR and X-ray flare and optically thick radio flare at 43 GHz that occurred on 2007 April 4. This would be the first evidence of a radio flare emission delayed with respect to the NIR and X-ray flare emission. The time delay measurements support the expansion of hot self-absorbed synchrotron plasma blob and weaken the hot spot model of flare emission.
Source arXiv, 0907.3786
Services Forum | Review | PDF | Favorites   
 
Visitor rating: did you like this article? no 1   2   3   4   5   yes

No review found.
 Did you like this article?

This article or document is ...
important:
of broad interest:
readable:
new:
correct:
Global appreciation:

  Note: answers to reviews or questions about the article must be posted in the forum section.
Authors are not allowed to review their own article. They can use the forum section.

browser claudebot






ScienXe.org
» my Online CV
» Free


News, job offers and information for researchers and scientists:
home  |  contact  |  terms of use  |  sitemap
Copyright © 2005-2024 - Scimetrica