arXiv subjects

R. Zanin

Publications and source records attributed to R. Zanin.

24 records · Page 2Linked to original sources

arXiv2012

Phase-resolved Crab pulsar measurements from 25 to 400 GeV with the MAGIC telescopes

We report on observations of the Crab pulsar with the MAGIC telescopes. Our data were taken in both monoscopic (> 25GeV) and stereoscopic (> 50GeV) observation modes. Two peaks were detected with both modes and phase-resolved energy spectra were calculated. By comparing with Fermi- LAT measurements, we find that the energy spectrum of the Crab pulsar does not follow a power law with an exponential cutoff, but has an additional hard component, extending up to at least 400 GeV. This suggests that the emission above 25 GeV is not dominated by curvature radiation, as suggested in the standard scenarios of the OG and SG models.

astro-ph.HE↗

arXiv2011

Performance of the MAGIC Stereo System

MAGIC is a system of two Imaging Atmospheric Cherenkov Telescopes sensitive above ~60 GeV, and located on the Canary Island of La Palma at the height of 2200 m.a.s.l. Since Autumn 2009 both telescopes are working together in stereoscopic mode. We use both Crab Nebula observations and Monte Carlo simulations to evaluate the performance of the system. Advanced stereo analysis allows MAGIC to achieve a sensitivity better than 0.8% of the Crab Nebula flux in 50 h of observations in the medium energy range (around a few hundred GeV). At those energies the angular resolution is better than 0.07{\circ}, and the energy resolution is as good as 16%. We perform also a detailed study of possible systematics effects for the MAGIC telescopes.

astro-ph.HE↗

arXiv2011

Observations of the Crab pulsar with the MAGIC telescopes

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 energy 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.

astro-ph.HE↗

arXiv2009

Microquasar observations with the MAGIC telescope

Microquasars, X-ray binaries displaying relativistic jets driven by accretion onto a compact object, are some of the most efficient accelerators in the Galaxy. Theoretical models predict Very High Energy (VHE) emission at the base of the jet where particles are accelerated to multi-TeV energies. This emission could be detected by present IACTs. %Moreover, gamma-ray fluxes should increase during flaring events when accretion rates are enhanced. The MAGIC telescope observed the microquasars GRS 1915+105, Cyg X-3, Cyg X-1 and SS433 for ~ 150 hours in total from 2005 to 2008. We triggered our observations by using multi wavelength information through radio flaring alerts with the RATAN telescope as well as by ensuring the low/hard state of the source through RXTE/ASM and Swift/BAT monitoring data. We report on the upper limits on steady and variable emission from these sources over this long period.

astro-ph.HE↗

arXiv2009

The Central Control of the MAGIC telescopes

The second MAGIC telescope, a clone of the first 17 m diameter MAGIC telescope, has entered the final commissioning phase and will soon start to take data, preferentially in the so-called stereo-mode. The control system for both telescopes is assigned to a number of autonomous functional units called subsystems. The control hardware and software components of the second telescope subsystems have been modified with respect to their counterparts of the first telescope. A new Central Control (CC) program has been developed to communicate with all the subsystems of both telescopes and to coordinate their functionality thus easing the stereo data taking procedure. We describe the whole control system in detail: all the subsystems and their communication with the Central Control, the CC graphic user interface that grants operators the full control over the two telescopes, and the automatic checking procedures, which guarantee the safety and 'health' of the apparatus.

astro-ph.IM↗

arXiv2007

Observations of microquasars with the MAGIC telescope

We report on the results from the observations in very high energy band (VHE, E_gamma > 100GeV) of the black hole X-ray binary (BHXB) Cygnus X-1. The observations were performed with the MAGIC telescope, for a total of 40 hours during 26 nights, spanning the period between June and November 2006. We report on the results of the searches for steady and variable gamma-ray signals, including the first experimental evidence for an intense flare, of duration between 1.5 and 24 hours.

astro-ph↗