Year: 2025
Type: conference-paper
Abstract: Imaging Atmospheric Cherenkov Telescopes (IACTs), including H.E.S.S., MAGIC, and VERITAS, have detected very-high-energy gamma rays from the central region of the Milky Way. The PeVatron hypothesis posits that the supermassive black hole Sagittarius A* (Sgr A*) accelerates cosmic rays to PeV energies, producing a diffuse gamma-ray emission extending up to tens of TeV across the central molecular zone. However, previous IACT studies have yielded inconsistent results due to methodological differences, complicating direct comparison and interpretation. H.E.S.S. initially suggested a power-law spectrum within the sector-annulus region (20-60 pc), whereas the MAGIC telescopes recently presented a 2-sigma hint of a spectral cutoff at ∼ 20 TeV for the total ridge emission (∼ 200 pc), although H.E.S.S. and VERITAS have not obtained a sign of cut-off for that emission. The first Large-Sized Telescope (LST-1) at the Northern site of the Cherenkov Telescope Array Observatory (CTAO) offers enhanced TeV sensitivity, despite its higher energy threshold, at large zenith angles. Its wide field of view (∼ 4.5 deg) enables more uniform Galactic ridge coverage than other Northern IACTs. In this study, LST-1 observations reconfirm a spectral cutoff around 20 TeV with a significance of about 3 sigma over a pure power law, demonstrating its capability of TeV observations of extended sources and refining our understanding of cosmic-ray acceleration in the Galactic Center.
DOI: 10.22323/1.501.0542
Authors: Shotaro Abe, Hidetoshi Kubo, Marcel C. Strzys, Masahiro Teshima, Ievgen Vovk, CTAO-LST Project
Institutions: Institute for Cosmic Ray Research, The University of Tokyo
Language: English
Subfield: Nuclear and High Energy Physics
Field: Physics and Astronomy
Domain: Physical Sciences
Open Access status: hybrid
Funders: National Science Foundation, Sveučilište u Zagrebu, Comunidad de Madrid, Ministerio de Ciencia, Innovación y Universidades, Centres de Recerca de Catalunya, European Commission, Deutsche Forschungsgemeinschaft, Ministry of Education, Culture, Sports, Science and Technology, Schweizerischer Nationalfonds zur Förderung der Wissenschaftlichen Forschung, Fundação de Amparo à Pesquisa do Estado de São Paulo, Ministerstvo Školství, Mládeže a Tělovýchovy, Bundesministerium für Bildung und Forschung, Generalitat de Catalunya, Conselho Nacional de Desenvolvimento Científico e Tecnológico, Max-Planck-Gesellschaft, Narodowe Centrum Nauki, Hrvatska Zaklada za Znanost, Fundação Carlos Chagas Filho de Amparo à Pesquisa do Estado do Rio de Janeiro, Fundação Araucária, Centre National de la Recherche Scientifique, Ministerio de Ciencia e Innovación, Istituto Nazionale di Astrofisica, Sveučilište Josipa Jurja Strossmayera u Osijeku, Junta de Andalucía, Ministério da Ciência, Tecnologia, Inovações e Comunicações, Istituto Nazionale di Fisica Nucleare, Japan Society for the Promotion of Science, Consejo Superior de Investigaciones Científicas, Staatssekretariat für Bildung, Forschung und Innovation, European Regional Development Fund, Agencia Estatal de Investigación, Institut National de Physique Nucléaire et de Physique des Particules, Institute for Cosmic Ray Research, University of Tokyo
Awards: G1059663884, G1089506725, G120905174, G1272927172, G1293671712, G1301723534, G1323383031, G1325701057, G1381791653, G1449231074, G1485410139, G176604203, G1767413778, G1888088267, G1953887145, G195395952, G196419191, G2030784793, G2209488408, G2233160401, G2309174360, G2313451655, G2507835933, G2554159582, Cherenkov Telescope Array - participation of the Czech Republic, G265847165, G2660406951, G2753747443, G278595929, G282847690, G291036901, G2988934680, Fermi gases in complex lattice structures: from Dirac points to Spin liquids, G302750986, G304813024, G3197651753, G3207356259, G3384621141, G3439265645, G3480869486, G348919436, G3490171961, G357246561, G3622461675, G363809202, G3690828678, G3715634343, G3735356012, G373897614, G3780874795, G3817602061, G3869365384, G393177772, G3978510197, G4087634877, G4104599821, G4238322289, G4317403835, G434337789, 癌細胞の遊離, 定着機構と転移抑制に関する研究, The Preparatory Phase for the Cherenkov Telescope Array
(CTA-PP), G463062595, G4760961572, G483893733, 原子炉による悪性皮膚腫瘍の選択的治療, G496129201, INtelligent Fast Interconnected and Efficient Devices for Frontier Exploitation in Research and Industry, G5011157824, G5080475149, G5243814431, Very-high-energy Gamma Ray Astronomy in the Multi-messenger Era, G529962013, G531036588, G545007060, G5555131222, G5641063287, G5662822759, G5702163051, G5845768719, G5894067328, G5915139351, G5916014575, Cherenkov Telescope Array: Infrastructure Development and Start of Implementation, G6033112984, G617610489, G6513613686, European Science Cluster of Astronomy & Particle physics ESFRI research infrastructures, G6649312515, G6791753710, G6941735741, G696452451, G7084143925, G7191602444, G7207111357, G7363506711, G7392162325, G7425137858, 古代説話における諸寺縁起の研究, G7805626310, G8079053745, G8347645112, G8373891351, G8546142835, G8639560392, G8684520763, G8752642921, G8792602865, G8920101981
OpenAlex ID: W4414425140
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