ترغب بنشر مسار تعليمي؟ اضغط هنا

Overview of the results from extra-galactic observations with the MAGIC telescopes

199   0   0.0 ( 0 )
 نشر من قبل Karsten Berger
 تاريخ النشر 2011
  مجال البحث فيزياء
والبحث باللغة English
 تأليف Karsten Berger




اسأل ChatGPT حول البحث

The non-thermal jet emission in active galactic nuclei covers several orders of magnitude in the frequency range. Hence the observational approach needs multi-wavelength (MWL) campaigns collecting data in the radio, optical, UV, X-rays, high energy until the Very High Energy (VHE) gamma-ray band. MAGIC, a system of two 17 m diameter telescopes at the Roque de los Muchachos observatory on the canary island La Palma, actively participates and organizes MWL observations on known and newly discovered VHE sources. In these proceedings we report the latest results of extra-galactic observations with MAGIC, which gained new insights in time variability studies and jet emission models.



قيم البحث

اقرأ أيضاً

We report on the observations of the Crab pulsar with the MAGIC telesopes. Data were taken both in the mono-mode ($>25$ GeV) and in the stereo-mode ($>50$ GeV). Clear signals from the two peaks were detected with both modes and the phase resolved ene rgy spectra were calculated. By comparing with the measurements done by Fermi-LAT, we found that the energy spectra of the Crab pulsar does not follow a power law with an exponential cutoff, but that it extends as a power law after the break at around 5 GeV. This suggests that the emission above 25 GeV is not dominated by the curvatura radiation, which is inconsistent with the standard prediction of the OG and SG models.
The improvement on the Imaging Air Cherenkov Technique (IACT) led to the discovery of a new type of sources that can emit at very high energies: the gamma-ray binaries. Only six systems are part of this exclusive class. We summarize the latest result s from the observations performed with the MAGIC telescopes on different systems as the gamma-ray binary LS I +61$^{circ}$ 303 and the microquasars SS433, V404 Cygni and Cygnus X-1, which are considered potential VHE gamma-ray emitters. The binary system LS I +61$^{circ}$ 303 has been observed by MAGIC in a long-term monitoring campaign. We show the newest results of our search for super-orbital variability also in context of contemporaneous optical observations. Besides, we will present the results of the only super-critical accretor known in our galaxy: SS 433. We will introduce the VHE results achieved with MAGIC after 100 hours of observations on the microquasar Cygnus X-1 and report on the microquasar V404 Cyg, which has been observed with MAGIC after it went through a series of exceptional X-ray outbursts in June 2015.
A population of globular clusters (GCs) has been recently established by the Fermi-LAT telescope as a new class of GeV $gamma$-ray sources. Leptons accelerated to TeV energies, in the inner magnetospheres of MSPs or in their wind regions, should prod uce $gamma$-rays through the inverse Compton scattering in the dense radiation field from the huge population of stars. We have conducted deep observations of the globular cluster M15 with the MAGIC telescopes and used 165 hrs in order to search for $gamma$-ray emission. A strong upper limit on the TeV $gamma$-ray flux $<3.2times 10^{-13}mathrm{cm^{-2}s^{-1}}$ above 300 GeV ($<0.26%$ of the Crab nebula flux) has been obtained. We interpret this limit as a constraint on the efficiency of the acceleration of leptons in the magnetospheres of the MSPs. We constrain the injection rate of relativistic leptons, $eta_{rm e}$, from the MSPs magnetospheres and their surrounding. We conclude that $eta_{rm e}$ must be lower than expected from the modelling of high energy processes in MSP inner magnetospheres. For leptons accelerated with the power law spectrum in the MSP wind regions, $eta_{rm e}$ is constrained to be much lower than derived for the wind regions around classical pulsars. These constraints are valid for the expected range of magnetic field strengths within the GC and for the range of likely energies of leptons injected from the inner magnetospheres, provided that the leptons are not removed from the globular cluster very efficiently due to advection process. We discuss consequences of these constraints for the models of radiation processes around millisecond pulsars.
59 - K. Coble , P.A.R. Ade , J.J. Bock 2003
We present millimeter-wave observations of three extra-galactic and six Galactic sources in the Southern sky. Observations were made at 90, 150, 240 and 400 GHz with resolutions of 18, 10, 14 and 12 arcmin respectively during the 1998 Antarctic long duration balloon flight of BOOMERANG. Observations were also made with the SEST telescope, at 90 and 150 GHz with resolutions of 57 and 35 arcsec respectively. These observations can be used for calibrations of Cosmic Microwave Background (CMB) experiments as well as an understanding of the physical processes of the sources.
We report new observations of the intermediate-frequency peaked BL Lacertae object 3C 66A with the MAGIC telescopes. The data sample we use were taken in 2009 December and 2010 January, and comprises 2.3 hr of good quality data in stereoscopic mode. In this period, we find a significant signal from the direction of the blazar 3C 66A. The new MAGIC stereoscopic system is shown to play an essential role for the separation between 3C 66A and the nearby radio galaxy 3C 66B, which is at a distance of only $6^prime$. The derived integral flux above $100eh{GeV}$ is 8.3% of Crab Nebula flux and the energy spectrum is reproduced by a power law of photon index $3.64 pm 0.39_{rm stat} pm 0.25_{rm sys}$. Within errors, this is compatible with the one derived by VERITAS in 2009. From the spectra corrected for absorption by the extragalactic background light, we only find small differences between the four models that we applied, and constrain the redshift of the blazar to $z < 0.68$.
التعليقات
جاري جلب التعليقات جاري جلب التعليقات
سجل دخول لتتمكن من متابعة معايير البحث التي قمت باختيارها
mircosoft-partner

هل ترغب بارسال اشعارات عن اخر التحديثات في شمرا-اكاديميا