Search for ultra-high energy photons through preshower effect with gamma-ray telescopes: Study of CTA-North efficiency

Abstract As ultra-high energy photons (EeV and beyond) propagate from their sources of production to Earth, radiation-matter interactions can occur, leading to an effective screening of the incident flux. In this energy domain, photons can undergo e + / e − pair production when interacting with the surrounding geomagnetic field, which in turn can produce a cascade of electromagnetic particles called preshower. Such cascade can initiate air showers in the Earth’s atmosphere that gamma-ray telescopes, such as the next-generation gamma-ray observatory Cherenkov Telescope Array, can detect through Cherenkov emission. In this paper, we study the feasibility of detecting such phenomenon using Monte-Carlo simulations of nearly horizontal air showers for the example of the La Palma site of the Cherenkov Telescope Array. We investigate the efficiency of multivariate analysis in correctly identifying preshower events initiated by 40 EeV photons and cosmic ray dominated background simulated in the energy range 10 TeV – 10 EeV. The effective areas for such kind of events are also investigated and event rate predictions related to different ultra-high energy photons production models are presented. While the expected number of preshowers from diffuse emission of UHE photons for 30 hours of observation is estimated around 3.3 × 10 − 5 based on the upper limits put by the Pierre Auger Observatory, this value is at the level of 2.7 × 10 − 4 ( 5.7 × 10 − 5 ) when considering the upper limits of the Pierre Auger Observatory (Telescope Array) on UHE photon point sources. However, UHE photon emission may undergo possible ”boosting” due to gamma-ray burst, increasing the expected number of preshower events up to 0.17 and yielding a minimum required flux of  ~ 0.2 km − 2 yr − 1 to obtain one preshower event, which is about a factor 10 higher than upper limits put by the Pierre Auger Observatory and Telescope Array (0.034 and 0.019 km − 2 yr − 1 , respectively).

[1]  A. Bell.  The acceleration of cosmic rays in shock fronts – I , 1978 .

[2]  S. Ostapchenko.  On the re-summation of enhanced pomeron diagrams , 2006, hep-ph/0602139.

[3]  J. W. Elbert,et al.  The Cosmic ray energy spectrum observed by the Fly's Eye , 1994 .

[4]  V. Berezinsky,et al.  Ultrahigh Energy Cosmic Rays without Greisen-Zatsepin-Kuzmin Cutoff , 1997 .

[5]  A. Neronov,et al.  Cosmic-ray composition measurements and cosmic ray background-free $\gamma$-ray observations with Cherenkov telescopes , 2016, 1610.01794.

[6]  P. Homola,et al.  Characteristics of geomagnetic cascading of ultra-high energy photons at the southern and northern sites of the Pierre Auger Observatory , 2006, astro-ph/0608101.

[7]  P. Munar-Adrover,et al.  Teraelectronvolt emission from the γ-ray burst GRB 190114C , 2019, Nature.

[8]  Todor StanevH.P. Vankov.  Nature of the highest energy cosmic rays , 1997 .

[9]  Murakami,et al.  Observation of a Very Energetic Cosmic Ray Well Beyond the Predicted 2.7 K Cutoff in the Primary Energy Spectrum. , 1994, Physical review letters.

[10]  Edward W. Kolb,et al.  Superheavy dark matter , 1998 .

[11]  A. Quirrenbach,et al.  Acceleration of petaelectronvolt protons in the Galactic Centre , 2016, Nature.

[12]  Piotr Homola,et al.  SEARCH FOR ULTRA-HIGH ENERGY PHOTONS USING AIR SHOWERS , 2007 .

[13]  Xavier Bertou,et al.  LPM effect and pair production in the geomagnetic field: a signature of ultra-high energy photons in the Pierre Auger Observatory , 2000 .

[14]  Detection of exotic massive hadrons in ultrahigh energy cosmic ray telescopes , 2009, 0901.3572.

[15]  C. A. Oxborrow,et al.  Planck 2013 results. XXI. All-sky Compton parameter power spectrum and high-order statistics , 2013, 1303.5081.

[16]  D. Heck,et al.  Simulation of ultra-high energy photon propagation in the geomagnetic field , 2005, Comput. Phys. Commun..

[17]  S. Bass,et al.  RELATIVISTIC HADRON-HADRON COLLISIONS IN THE ULTRA-RELATIVISTIC QUANTUM MOLECULAR DYNAMICS MODEL , 1999, hep-ph/9909407.

[18]  William H. Lee,et al.  Multimessenger observations of a flaring blazar coincident with high-energy neutrino IceCube-170922A , 2018, Science.

[19]  A. Chilingarian,et al.  Implementation of the Random Forest method for the Imaging Atmospheric Cherenkov Telescope MAGIC , 2007, 0709.3719.

[20]  Heidelberg,et al.  Gamma-Hadron Separation in Very-High-Energy gamma-ray astronomy using a multivariate analysis method , 2009, 0904.1136.

[21]  G. Gelmini,et al.  GZK photons as ultra-high-energy cosmic rays , 2005, astro-ph/0506128.

[22]  J. M. Paredes,et al.  Limits on the flux of tau neutrinos from 1 PeV to 3 EeV with the MAGIC telescopes , 2018, Astroparticle Physics.

[23]  S. Fliescher,et al.  Update on the correlation of the highest energy cosmic rays with nearby extragalactic matter , 2010, 1009.1855.

[24]  B. Matthews.  Comparison of the predicted and observed secondary structure of T4 phage lysozyme. , 1975, Biochimica et biophysica acta.

[25]  J. P. Barron,et al.  Neutrino emission from the direction of the blazar TXS 0506+056 prior to the IceCube-170922A alert , 2018, Science.

[26]  T. Erber,et al.  High-Energy Electromagnetic Conversion Processes in Intense Magnetic Fields , 1966 .

[27]  W. Bednarek.  Cascades initiated by EHE photons in the magnetic field of the Earth and the Sun , 1999 .

[28]  F. Tegenfeldt,et al.  TMVA - Toolkit for multivariate data analysis , 2012 .

[29]  L. D. Landau,et al.  Limits of applicability of the theory of bremsstrahlung electrons and pair production at high-energies , 1953 .

[30]  A.Suzuki,et al.  Discovery of TeV Gamma Rays from SN1006: Further Evidence for the SNR Origin of Cosmic Rays , 1998 .

[31]  V. Golev,et al.  Design concepts for the Cherenkov Telescope Array CTA: an advanced facility for ground-based high-energy gamma-ray astronomy , 2011 .

[32]  C. A. Sarmiento,et al.  A targeted search for point sources of EeV photons with the Pierre Auger Observatory , 2016, 1612.04155.

[33]  S. Ostapchenko.  Nonlinear screening effects in high energy hadronic interactions , 2005, hep-ph/0505259.

[34]  S. Bass,et al.  Microscopic models for ultrarelativistic heavy ion collisions , 1998, nucl-th/9803035.

[35]  Danna Zhou,et al.  d. , 1840, Microbial pathogenesis.

[36]  K. Bernlohr,et al.  Simulation of Imaging Atmospheric Cherenkov Telescopes with CORSIKA and sim_telarray , 2008, 0808.2253.

[37]  J. Ellis,et al.  Ultrahigh-energy cosmic rays particle spectra from crypton decays , 2006 .

[38]  Colin J. Lambert,et al.  Interactions of high-energy ( E > 5 × 10 19 eV) photons in the Earth's magnetic field , 1981 .

[39]  K. Greisen.  End to the cosmic ray spectrum , 1966 .

[40]  A. Quirrenbach,et al.  A very-high-energy component deep in the γ-ray burst afterglow , 2019, Nature.