Mohanraj Senniappan

RESEARCH, TEACHING, or OTHER INTERESTS

Physics and Astronomy

Scopus Publications

Searching for gamma-ray counterparts of FRBs with H.E.S.S.




Joint H.E.S.S. and Fermi-LAT analysis of the region around PSR J1813-1749




Modelling of highly extended Gamma-ray emission around the Geminga Pulsar as detected with H.E.S.S.




Joint searches by FACT, H.E.S.S., MAGIC and VERITAS for VHE gamma-ray emission associated with neutrinos detected by IceCube




Search for dark matter annihilation line signals with the H.E.S.S. Inner Galaxy Survey




Multiwavelength Observations of the Blazar PKS 0735+178 in Spatial and Temporal Coincidence with an Astrophysical Neutrino Candidate IceCube-211208A




H.E.S.S. follow-up observation of GRB221009A




Towards the second H.E.S.S. Galactic plane catalogue




The Eta Carinae 2020 periastron passage as seen by H.E.S.S.




Target of Opportunity observations of flaring blazars with H.E.S.S.




Sensitivity to point-like sources of the ALTO atmospheric particle detector array, designed for 200 GeV–50 TeV γ-ray astronomy
M. Punch, M. Senniappan, Y. Becherini, G. Kukec Mezek, S. Thoudam, T. Bylund, and J.-P. Ernenwein
Elsevier BV



Search for Dark Matter Annihilation Signals in the H.E.S.S. Inner Galaxy Survey
H. Abdalla, F. Aharonian, F. Ait Benkhali, E. O. Angüner, C. Armand, H. Ashkar, M. Backes, V. Baghmanyan, V. Barbosa Martins, R. Batzofin,et al.
American Physical Society (APS)
The central region of the Milky Way is one of the foremost locations to look for dark matter (DM) signatures. We report the first results on a search for DM particle annihilation signals using new observations from an unprecedented γ-ray survey of the Galactic Center (GC) region, i.e., the Inner Galaxy Survey, at very high energies (≳100  GeV) performed with the H.E.S.S. array of five ground-based Cherenkov telescopes. No significant γ-ray excess is found in the search region of the 2014-2020 dataset and a profile likelihood ratio analysis is carried out to set exclusion limits on the annihilation cross section ⟨σv⟩. Assuming Einasto and Navarro-Frenk-White (NFW) DM density profiles at the GC, these constraints are the strongest obtained so far in the TeV DM mass range. For the Einasto profile, the constraints reach ⟨σv⟩ values of 3.7×10^{-26}  cm^{3} s^{-1} for 1.5 TeV DM mass in the W^{+}W^{-} annihilation channel, and 1.2×10^{-26}  cm^{3} s^{-1} for 0.7 TeV DM mass in the τ^{+}τ^{-} annihilation channel. With the H.E.S.S. Inner Galaxy Survey, ground-based γ-ray observations thus probe ⟨σv⟩ values expected from thermal-relic annihilating TeV DM particles.


Time-resolved hadronic particle acceleration in the recurrent nova RS Ophiuchi
, F. Aharonian, F. Ait Benkhali, E. O. Angüner, H. Ashkar, M. Backes, V. Baghmanyan, V. Barbosa Martins, R. Batzofin, Y. Becherini,et al.
American Association for the Advancement of Science (AAAS)
Recurrent novae are repeating thermonuclear explosions in the outer layers of white dwarfs, due to the accretion of fresh material from a binary companion. The shock generated when ejected material slams into the companion star’s wind can accelerate particles. We report very-high-energy (VHE; ≳ 100   giga–electron volts ) gamma rays from the recurrent nova RS Ophiuchi, up to 1 month after its 2021 outburst, observed using the High Energy Stereoscopic System (H.E.S.S.). The temporal profile of VHE emission is similar to that of lower-energy giga–electron volt emission, indicating a common origin, with a 2-day delay in peak flux. These observations constrain models of time-dependent particle energization, favoring a hadronic emission scenario over the leptonic alternative. Shocks in dense winds provide favorable environments for efficient acceleration of cosmic rays to very high energies.


Search for enhanced TeV gamma-ray emission from Giant Molecular Clouds using H.E.S.S.




The young massive stellar cluster Westerlund 1 in γ rays as seen with H.E.S.S.




Evidence of 100 TeV γ-ray emission from HESS J1702-420: A new PeVatron candidate




H.E.S.S. follow-up of BBH merger events




Science verification of the new FlashCam-based camera in the 28 m telescope of H.E.S.S.




The CoMET multiperspective event tracker for wide field-of-view gamma-ray astronomy




Is PKS 0625−354 another variable TeV active galactic nucleus?




Detection of new Extreme BL Lac objects with H.E.S.S. and Swift XRT




Deep observations of Kepler's SNR with H.E.S.S.




H.E.S.S. ToO program on nearby core-collapse Supernovae: search for very-high energy γ-ray emission towards the SN candidate AT2019krl in M74




Combined dark matter searches towards dwarf spheroidal galaxies with Fermi-LAT, HAWC, H.E.S.S., MAGIC, and VERITAS




Observation of burst activity from SGR1935+2154 associated to first galactic FRB with H.E.S.S.

RECENT SCHOLAR PUBLICATIONS

Galactic Centre with a Southern Wide Field-of-view Gamma-ray Observatory
JA Hinton, A Albert, F Aharonian, F Ait-Benkhali, A Alkan, J Aschersleben, ...
38th International Cosmic Ray Conference, 893 2024



Monitoring the first candidate host for the merger of a Supermassive Black Hole Binary with HESS
F Aharonian, F Ait-Benkhali, A Alkan, J Aschersleben, H Ashkar, ...
38th International Cosmic Ray Conference, 688 2024



Probing the morphology of the low state gamma-ray emission of M87 with HESS
C Arcaro, N Mathieu, F Aharonian, F Ait-Benkhali, A Alkan, ...
38th International Cosmic Ray Conference, 696 2024



An updated view of the VHE gamma-ray sky around the stellar cluster Westerlund 2 with the HESS experiment
TL Holch, F Aharonian, F Ait-Benkhali, A Alkan, J Aschersleben, H Ashkar, ...
38th International Cosmic Ray Conference, 778 2024



Joint searches by FACT, HESS, MAGIC and VERITAS for VHE gamma-ray emission associated with neutrinos detected by IceCube
F Schssler, H Ashkar, E Bernardini, A Berti, F Bradascio, S Buson, ...
arXiv preprint arXiv:2309.15469 2023



Sensitivity to point-like sources of the ALTO atmospheric particle detector array, designed for 200 GeV–50 TeV γ-ray astronomy
M Punch, M Senniappan, Y Becherini, GK Mezek, S Thoudam, T Bylund, ...
Journal of High Energy Astrophysics 39, 1-13 2023



Searching for gamma-ray counterparts of FRBs with HESS
F Aharonian, FA Benkhali, A Alkan, J Aschersleben, H Ashkar, M Backes, ...
38th International Cosmic Ray Conference, 776 2023



Sensitivity to point-like sources of the ALTO atmospheric particle detector array, designed for -- -ray astronomy
M Punch, M Senniappan, Y Becherini, GK Mezek, S Thoudam, T Bylund, ...
arXiv preprint arXiv:2303.15248 2023



Search for dark matter annihilation signals in the HESS inner galaxy survey
H Abdalla, F Aharonian, FA Benkhali, EO Angner, C Armand, H Ashkar, ...
Physical review letters 129 (11), 111101 2022



Time-resolved hadronic particle acceleration in the recurrent nova RS Ophiuchi
HESS Collaboration*†, F Aharonian, F Ait Benkhali, EO Angner, ...
Science 376 (6588), 77-80 2022



HESS follow-up of BBH merger events
H Collabortion, M Arroyo Seglar, H Abdalla, F Aharonian, F Ait-Benkhali, ...
37th International Cosmic Ray Conference (ICRC2021) 2022



Search for TeV emission from the Fermi Bubbles at low Galactic latitudes with HESS inner Galaxy survey
H Abdalla, F Aharonian, F Ait-Benkhali, O Anguener, C Arcaro, C Armand, ...
37th International Cosmic Ray Conference, 791 2022



Searching for VHE gamma-ray emission associated with IceCube neutrino alerts using FACT, HESS, MAGIC, and VERITAS
S Ansoldi, LA Antonelli, A Arbet Engels, M Artero, K Asano, D Baack, ...
arXiv preprint arXiv:2109.04350 2022



Revealing time-resolved particle acceleration in the recurrent Nova RS Ophiuchi
F Aharonian, F Ait Benkhali, EO Angner, H Ashkar, M Backes, ...
arXiv e-prints, arXiv: 2202.08201 2022



Is PKS 0625-354 another variable TeV active galactic nucleus?
H Abdalla, F Aharonian, F Ait-Benkhali, O Anguener, C Arcaro, C Armand, ...
2022



Limits on primordial black hole evaporation from HESS observations
H Abdalla, F Aharonian, F Ait Benkhali, EO Angner, C Arcaro, C Armand, ...
Proceedings of Science 395 2022



Limits on primordial black hole evaporation from HESS observations
T Tavernier, JF Glicenstein, F Brun, V Marandon, H Abdalla, F Aharonian, ...
2022



Detection of new Extreme BL Lac objects with HESS and Swift XRT
M de Bony, T Bylund, M Meyer, A Noel, D Sanchez, H Abdalla, ...
2022



Deep observations of Kepler's SNR with HESS
H Abdalla, F Aharonian, F Ait Benkhali, EO Angner, C Arcaro, C Armand, ...
Proceedings of Science 395 2022



HESS ToO program on nearby core-collapse Supernovae: search for very-high energy γ-ray emission towards the SN candidate AT2019krl in M74
S Ryder, H Abdalla, F Aharonian, F Ait Benkhali, EO Angner, C Arcaro, ...
Proceedings of Science 395 2022

MOST CITED SCHOLAR PUBLICATIONS

A very-high-energy component deep in the γ-ray burst afterglow
H Abdalla, R Adam, F Aharonian, F Ait Benkhali, EO Angner, M Arakawa, ...
Nature 575 (7783), 464-467 2019
Citations: 351



Revealing x-ray and gamma ray temporal and spectral similarities in the GRB 190829A afterglow
HESS collaboration, H Abdalla, F Aharonian, F Ait Benkhali, EO Angner, ...
Science 372 (6546), 1081-1085 2021
Citations: 187



Broadband multi-wavelength properties of M87 during the 2017 Event Horizon Telescope campaign
JC Algaba, J Anczarski, K Asada, M Baloković, S Chandra, YZ Cui, ...
The Astrophysical Journal Letters 911 (1), L11 2021
Citations: 115



Search for dark matter annihilation signals in the HESS inner galaxy survey
H Abdalla, F Aharonian, FA Benkhali, EO Angner, C Armand, H Ashkar, ...
Physical review letters 129 (11), 111101 2022
Citations: 101



The 2014 TeV γ-ray flare of Mrk 501 seen with HESS: temporal and spectral constraints on Lorentz invariance violation
H Abdalla, F Aharonian, FA Benkhali, EO Angner, M Arakawa, C Arcaro, ...
The Astrophysical Journal 870 (2), 93 2019
Citations: 91



Particle transport within the pulsar wind nebula HESS J1825–137
H Abdalla, F Aharonian, FA Benkhali, EO Angner, M Arakawa, C Arcaro, ...
Astronomy & Astrophysics 621, A116 2019
Citations: 89



First ground-based measurement of sub-20 GeV to 100 GeV γ-Rays from the Vela pulsar with HESS II
H Abdalla, F Aharonian, FA Benkhali, EO Angner, M Arakawa, C Arcaro, ...
Astronomy & Astrophysics 620, A66 2018
Citations: 79



Time-resolved hadronic particle acceleration in the recurrent nova RS Ophiuchi
HESS Collaboration*†, F Aharonian, F Ait Benkhali, EO Angner, ...
Science 376 (6588), 77-80 2022
Citations: 78



Searches for gamma-ray lines and ‘pure WIMP’spectra from Dark Matter annihilations in dwarf galaxies with HESS
M Cirelli, P Panci, F Sala, J Silk, M Taoso, H Abdalla, F Aharonian, ...
Journal of cosmology and astroparticle physics 2018 (11), 037 2018
Citations: 66



Search for dark matter signals towards a selection of recently detected DES dwarf galaxy satellites of the Milky Way with HESS
H Abdallah, R Adam, F Aharonian, F Ait Benkhali, EO Angner, ...
Physical Review D 102 (6), 062001 2020
Citations: 61



The starburst galaxy NGC 253 revisited by HESS and Fermi-LAT
H Abdalla, F Aharonian, FA Benkhali, EO Angner, M Arakawa, C Arcaro, ...
Astronomy & Astrophysics 617, A73 2018
Citations: 61



Constraints on the emission region of 3C 279 during strong flares in 2014 and 2015 through VHE γ-ray observations with HESS
H Abdalla, R Adam, F Aharonian, FA Benkhali, EO Angner, M Arakawa, ...
Astronomy & Astrophysics 627, A159 2019
Citations: 60



Evidence of 100 TeV γ-ray emission from HESS J1702-420: A new PeVatron candidate
H Abdalla, F Aharonian, FA Benkhali, EO Angner, C Arcaro, C Armand, ...
Astronomy & Astrophysics 653, A152 2021
Citations: 37



HESS and MAGIC observations of a sudden cessation of a very-high-energy γ-ray flare in PKS 1510− 089 in May 2016
H Abdalla, R Adam, F Aharonian, FA Benkhali, EO Angner, C Arcaro, ...
Astronomy & astrophysics 648, A23 2021
Citations: 35



HESS and Fermi-LAT observations of PSR B1259–63/LS 2883 during its 2014 and 2017 periastron passages
H Abdalla, R Adam, F Aharonian, FA Benkhali, EO Angner, M Arakawa, ...
Astronomy & Astrophysics 633, A102 2020
Citations: 32



Detection of very-high-energy γ-ray emission from the colliding wind binary η Car with HESS
H Abdalla, R Adam, F Aharonian, FA Benkhali, EO Angner, M Arakawa, ...
Astronomy & Astrophysics 635, A167 2020
Citations: 31



HESS and Suzaku observations of the Vela X pulsar wind nebula
H Abdalla, F Aharonian, FA Benkhali, EO Angner, M Arakawa, C Arcaro, ...
Astronomy & Astrophysics 627, A100 2019
Citations: 28



TeV emission of Galactic plane sources with HAWC and HESS
H Abdalla, F Aharonian, FA Benkhali, EO Angner, C Arcaro, C Armand, ...
The Astrophysical Journal 917 (1), 6 2021
Citations: 27



HESS detection of very high-energy γ-ray emission from the quasar PKS 0736+ 017
H Abdalla, R Adam, F Aharonian, FA Benkhali, EO Angner, M Arakawa, ...
Astronomy & Astrophysics 633, A162 2020
Citations: 26



Observation of the Gamma-Ray Binary HESS J0632+ 057 with the HESS, MAGIC, and VERITAS Telescopes
CB Adams, W Benbow, A Brill, JH Buckley, M Capasso, AJ Chromey, ...
The Astrophysical Journal 923 (2), 241 2021
Citations: 25