Sources emitting gamma-rays observed in the MAGIC field of view Jelena-Kristina Željeznjak , Zagreb

Content Theoretical and technical background Introduction Cherenkov radiation IACT and MAGIC MAGIC telescopes compared to FERMI satellite Astrophysical sources Data analysis Motivation Wobble positions Implementation Results Conclusion Literature

Introduction Gamma rays: the most energetic part of the electromagnetic spectrum, everything above 100 keV Opacity of Earth's atmosphere: Stops x-rays and gamma rays We can get information indirectly

Introduction Radiation from space:  99.9% cosmic radiation: 90% protons 9.9% α, heavy ions, electrons Only 0.1% are gammas Only electrically neutral particles preserve information about the direction of their source Other neutral candidates: Neutrinos – hard to detect WIMP, neutralino -only theoretical

Spectral energy distribution Spectral energy distribution of the Crab Nebula from 100 MeV to ∼ 30 TeV obtained by Fermi-LAT and MAGIC, together with the fit results from other gamma ray experiments.

Cherenkov radiation Pavel Alekseyevich Cherenkov When a fast particle moves through a medium at a constant velocity v greater than the speed of light in that medium Emits radiation that can be detected as an optical signal Photon entering the atmosphere has to have energy greater than 2m e c 2 ~1022 MeV pair production gamma -> e + e - Electron-positron pairs lose energy by brehmsstrahlung, creating secondary high energy photons. Those photons, in turn, create new electron-positron pairs and so on.

Cherenkov radiation Cascade of photons, electrons and positrons h moves in the direction of the primary gamma ray Photons are emmited at characteristic angle function of the density of the atmosphere density of the atmosphere is very low the angle is relatively small, around 1° very focused, relatively small light pool on the ground with the diameter of ~250 m

Cascade

IACT and MAGIC Imaging: detectors use a mirror and a camera Air shower of charged particles in the atmosphere, it becomes a part of the detection mechanism Cherenkov source is observed indirectly by observing Cherenkov photons caused by gamma-rays Telescope Current big IACTs: H.E.S.S., MAGIC and VERITAS

MAGIC Telescopes Mayor Atmospheric Gamma-ray Imaging Cherenkov Telescopes Sensitive to gamma-rays between 25 GeV an 30 TeV

Image formation

diameter of ~250 m the light intensity per unit area on ground is low detection of a gamma imagining anywhere inside this disk, i.e. an effective area of 30 to m 2 the signals are weak

Image formation

Dark time

Satellites vs ground telescopes detectors on satellites have many benefits: no atmosphere disregarding daylight conditions Fermi Gamma-ray Space Telescope: 20 MeV – 300 GeV Survey the whole sky every 3 hour Field of view 60° vs 1.8° for MAGIC Small effective area: FERMI ~0.8 m 2 at 1 GeV where it is most effective MAGIC effective area of 30 to m 2

CTA and the future of IACTs Cherenkov Telescope Array (CTA) next generation ground-based very high energy gamma-ray instrument VHE (E > 10 GeV) gamma-rays the design foresees a factor of 5-10 improvement in sensitivity in the current VHE gamma-ray domain of about 100 GeV to ~10 TeV extension of the accessible energy range from well below 100 GeV to above 100 TeV

Astrophysical sources Galactic: Supernova remnants Pulsars Crab Nebula Extragalactic: Active galactic nuclei Gamma ray bursts

Data analysis Post upgrade of 2012, Novemeber 2012 – March 2015 Code has broader application – MAGIC Legacy web tool Gathers data from periods and makes a new data set

Sensitivity in the FOV Gamma rates above 290 GeV for low zenith angle observations at different offsets from camera center.

Wobble positions Standard 4 wobble positions Some sources have custom wobble positions Crab Nebula

Results FERMI 2 year gives 252 sources in the FOV of the~70 sources MAGIC observes FERMI 4 year catalogue gives 322

Area surrounding Crab Nebula and IC443 In periods h dark time and h moon/twilight conditions for the Crab Nebula 11 sources in FERMI2

Area surrounding Crab Nebula and IC sources in FERMI2 29 sources in FERMI3

Area surrounding H

Conclusion Many sources detected by FERMI in MAGIC FOV Code can be used to check if a source was observed at same coordinates but under different name Broader applications → MAGIC legacy web tool

Bibliography [1] Official MAGIC Collaboration web-page, April 2015, [2] Malcolm S. Longair. High energy astrophysics, 3rd edition. Cambridge University Press, [3] Bradley W. Carroll and Dale A. Ostlie. An introduction to modern astrophysics, 2nd edition. Addison-Wesley, [4] CTA-argentina, [5] Aleksić et al. (MAGIC Collaboration). The major upgrade of the magic telescopes, part ii: A performance study using observations of the crab nebula., Fri, 20 Feb URL abs/ [6] Cherenkov telescope array official web-page. April [7] T.Bretz et al. Vol. 4, , Contributions to ICRC 2005, Pune, April URL icrc05/dorner_wobble.pdf. [8] Nasa fermi: Lat 2-year point source catalog. April URL gsfc.nasa.gov/ssc/data/access/lat/2yr_catalog/. [9] Nasa fermi: Lat 4-year point source catalog. April URL gsfc.nasa.gov/ssc/data/access/lat/4yr_catalog/. [10] Aleksić et al. (MAGIC Collaboration). Measurement of the Crab nebula spectrum over three decades in energy with the magic telescopes. Thu, 26 Jun URL