The spectrum of Sgr A * and its variability

نویسندگان

  • Peter G. Mezger
  • Wolfgang J. Duschl
  • Harald Lesch
چکیده

We demonstrate that there is only one physical process required to explain the spectrum and the variability of the radio source at the dynamical center of our Galaxy, Sgr A*, in the frequency range from 1 to 1000 GHz, namely optically thin synchrotron radiation that is emitted from a population of relativistic electrons. We attribute the observed variability to variable energy input from an accretion disk around Sgr A* into the acceleration of the electrons.

برای دانلود متن کامل این مقاله و بیش از 32 میلیون مقاله دیگر ابتدا ثبت نام کنید

ثبت نام

اگر عضو سایت هستید لطفا وارد حساب کاربری خود شوید

منابع مشابه

The Rapid X-ray Variability of Gm Sagittarii (sax J1819.3–2525 = Xte J1819–254)

We report on the rapid X-ray variability of the variable star and X-ray transient GM Sgr (SAX J1819.3–2525; XTE J1819–254) as observed on 15 Sept. 1999 by the proportional counter array (PCA) on board the Rossi X-ray Timing Explorer (RXTE). During the first ∼900 seconds of the first RXTE/PCA observation, GM Sgr showed very strong Xray fluctuations by a factor of 4 on time scales of seconds to a...

متن کامل

The jet model for Sgr A*: Radio and X-ray spectrum

The preliminary detection of the Galactic Center black hole Sgr A* in X-rays by the Chandra mission, as well as recent mm-VLBI measurements, impose strict constraints on this source. Using a relativistic jet model for Sgr A*, we calculate the synchrotron and synchrotron self-Compton emission. The predicted spectrum provides an excellent fit to the radio spectrum and the X-ray observations. Limi...

متن کامل

Sgr A* and Company -multiwavelength Observations of Sgr A* and Vla Search of " Sgr A*'s " in Liners

We report first results from a multiwavelength campaign to measure the simultaneous spectrum of Sgr A* from cm to mm wavelengths. The observations confirm that the previously detected submm-excess is not due to variability; the presence of an ultracompact component with a size of a few Schwarzschild radii is inferred. In a VLA survey of LINER galaxies, we found Sgr A*-like nuclei in one quarter...

متن کامل

داده‌کاهی و آنالیز تصاویر چند باندی نوری بلازار 180 Mrk

 Nearly simultaneous multiband monitoring of blazars is very limited and most studies reported in literature are conflicting, too. Although optical variability on intra-night timescales is now a well established phenomenon for blazars, its relationship to long-term variability remains unclear. Possible clues could come from monitoring the optical spectrum for correlation with brightness. The pr...

متن کامل

The Rapid X-Ray Variability of V4641 Sagittarii (SAX J1819.3-2525 = XTE J1819-254).

We report on the rapid X-ray variability of the variable star and X-ray transient V4641 Sagittarii (SAX J1819.3-2525 = XTE J1819-254) as observed on 1999 September 15 by the proportional counter array (PCA) on board the Rossi X-Ray Timing Explorer. During the first approximately 900 s of the first PCA observation, V4641 Sgr showed very strong X-ray fluctuations by a factor of 4 on timescales of...

متن کامل

ذخیره در منابع من


  با ذخیره ی این منبع در منابع من، دسترسی به آن را برای استفاده های بعدی آسان تر کنید

برای دانلود متن کامل این مقاله و بیش از 32 میلیون مقاله دیگر ابتدا ثبت نام کنید

ثبت نام

اگر عضو سایت هستید لطفا وارد حساب کاربری خود شوید

عنوان ژورنال:

دوره   شماره 

صفحات  -

تاریخ انتشار 1994