Microquasar Cyg X-3 -- a unique jet-wind neutrino factory?

The origin of astrophysical neutrinos is one of the most debated topics today. Perhaps the most robust evidence of neutrino counterpart comes from supermassive black holes in active galactic nuclei associated with strongly collimated outflows, or jets, that can accelerate particles to relativistic energies and produce neutrinos through hadronic interactions. Similar outflows can also be found from X-ray binaries, or `microquasars', that consist of a neutron star or a stellar-mass black hole accreting matter from a non-degenerate companion star. In some cases, these systems can accelerate particles up to GeV energies implying an efficient acceleration mechanism in their jets. Neutrino production in microquasar jets can be expected with suitable conditions and a hadronic particle population. Microquasar Cyg X-3 is a unique, short orbital period X-ray binary hosting a Wolf-Rayet companion star with a strong stellar wind. The interaction of the dense stellar wind with a relativistic jet leads to particle collisions followed by high-energy gamma-ray and potentially neutrino emission. Here, using the 10-year neutrino candidate sample of the IceCube neutrino observatory, we find that the events with the highest spatial association with Cyg X-3 occur during short-lived high-energy gamma-ray flaring periods indicating the possible astrophysical nature of these events.Comment: 5 pages, 2 figures, 1 table. This article has been accepted for publication in MNRAS published by Oxford University Press on behalf of the Royal Astronomical Societ

MAGIC gamma-ray telescopes hunting for neutrinos and their sources

The discovery of an astrophysical flux of high-energy neutrinos by the IceCube Collaboration marks a major breakthrough in the ongoing search for the origin of cosmic rays. Presumably, the neutrinos, together with gamma rays, result from pion decay, following hadronic interactions of protons accelerated in astrophysical objects to ultra-relativistic energies. So far, the neutrino sky map shows no significant indication of astrophysical sources. Here, we report first results from follow-up observations, of sky regions where IceCube has detected muon tracks from energetic neutrinos, using the MAGIC telescopes which are sensitive to gamma rays at TeV energies. Furthermore, we show that MAGIC has the potential to distinguish air showers induced by tau neutrinos from the background of hadronic showers in the PeV-EeV energy range, employing a novel analysis method to the data obtained with high-zenith angle observations.Peer Reviewe

Data processing activities at the MAGIC site

open11siMAGIC is a system of two imaging atmospheric Cherenkov telescopes located on the Canary Is- land of La Palma. The fast processing of the data at the observation site plays an essential part in the operation of the telescopes and has continuously improved since the beginning of the exper- iment. The on-site computing can be divided into three major contributions: the MAGIC online analysis (MOLA), providing preliminary real time analysis results; the on-site analysis (OSA), providing final data products at the end of each observation night; and the Data Check (DC), a daily check on the performance of the telescope’s subsystems and the quality control of the data observed during the previous night. We present the status of the system, including the latest upgrades and details on its performance.openFidalgo, David; Nievas-Rosillo, Miguel; Babic, Ana; Contreras, Jose-Luis; Doro, Michele; Godinovic, Nikola; Hrupec, Dario; Lorca, Alejandro; Moralejo, Abelardo; Satalecka, Konstancja; Will, MartinFidalgo, David; Nievas Rosillo, Miguel; Babic, Ana; Contreras, Jose Luis; Doro, Michele; Godinovic, Nikola; Hrupec, Dario; Lorca, Alejandro; Moralejo, Abelardo; Satalecka, Konstancja; Will, Marti

35th International Cosmic Ray Conference, ICRC 2017

We report on the detection of flaring activity from the prominent Fanaroff-Riley I radio galaxy NGC 1275 located in the Perseus cluster of galaxies in the very-high-energy gamma-ray band. The observations were performed with the MAGIC telescopes between 2016 and 2017 over several months. During this time period, the mean flux above 100 GeV was measured to be roughly ten times brighter than during previous observations. The night-by-night light curve above 100 GeV shows several peaks indicating flux-doubling time-scales of shorter than one day much smaller than the monthly time-scale previously detected by MAGIC. The brightest flux, observed around December 2016 and January 2017, reached 1.75 times the flux from the Crab Nebula, i.e. was about sixty times brighter than the average flux of the previous years. The spectral energy distribution measured up to > 1 TeV shows a curved shape unlike the previously measured simple power-law. The angle between the jet-axis and the line-of sight of NGC 1275 was formerly found to be 30-55 degree in the radio band excluding strong Doppler boosting of the emitted radiation towards the observer. The fast TeV flux variability and the spectral behaviour observed from a non-blazar object challenge current standard theoretical models and therefore, provide new and fascinating insights into the gamma-ray production and emission mechanism of active galactic nuclei. In the conference, we present the observational results and discuss possible physical processes responsible for the flaring events.</p

Monitoring of Bright Blazars with MAGIC in the 2007/2008 Season

Because of the short duty-cycles and observation-time constraints, studies of bright TeV (E>100 GeV) blazars are mostly restricted to flaring episodes or rather short (days to few weeks) multiwavelength campaigns. At the same time, long-term studies of these objects are essential to gain a more complete understanding of the blazar phenomenon and to constrain theoretical models concerning jet physics. Only unbiased long-term studies are adequate for the determination of flaring state probabilities and for estimating the statistical significance of possible correlations between TeV flaring states and other wavebands or observables, such as neutrino events. Regular observations also provide triggers for multiwavelength ToO observations originating from the TeV waveband. These are particularly needed to identify and study orphan TeV flares, i.e. flares without counterparts in other wavebands. In 2007/8 the MAGIC telescope has monitored three TeV blazars on a regular basis: Mrk 501, Mrk 421, and 1ES 1959+650. We present preliminary results of these observations including the measured light curves and a correlation study for VHE gamma-rays and X-rays and VHE gamma-rays and optical R-band for Mrk 421.Comment: 10 pages, 7 figures, Proceedings of the SciNEGHE'0