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Observation of Ultra-High-Energy Gamma Rays and Search for Dark Matter Signatures in the Galactic Center with the HAWC Observatory
Observation of Ultra-High-Energy Gamma Rays and Search for Dark Matter Signatures in the Galactic Center with the HAWC Observatory
상세정보
- 자료유형
- 학위논문 서양
- 최종처리일시
- 20260202103118
- ISBN
- 9798286437030
- DDC
- 523
- 서명/저자
- Observation of Ultra-High-Energy Gamma Rays and Search for Dark Matter Signatures in the Galactic Center with the HAWC Observatory
- 발행사항
- [Sl] : University of Maryland, College Park, 2025
- 발행사항
- Ann Arbor : ProQuest Dissertations & Theses, 2025
- 형태사항
- 167 p
- 주기사항
- Source: Dissertations Abstracts International, Volume: 86-12, Section: B.
- 주기사항
- Advisor: Goodman, Jordan A.
- 학위논문주기
- Thesis (Ph.D.)--University of Maryland, College Park, 2025.
- 초록/해제
- 요약The center of our Galaxy is an intriguing region in astrophysics, providing a unique opportunity to study various astrophysical processes. However, our line of sight is obscured by dense layers of dust and gas, making optical emission observation impossible. Fortunately, we can observe other portions of the electromagnetic spectrum, such as radio, X-rays, and gamma rays. The latter serve as probes of cosmic-ray acceleration to extremely high energies and, in theory, for indirect Dark Matter (DM) detection. This dissertation analyzes gamma-ray data from the Galactic Center (GC), obtained with the High-Altitude Water Cherenkov (HAWC) Gamma-Ray Observatory.The HAWC Observatory, situated on the Sierra Negra volcano in Mexico at an altitude of 4,100 m, detects gamma rays with energies from 0.1 to greater than 100 TeV. It has a wide field of view of about 2 sr, and with an operational duty cycle of over 95%, it observes two-thirds of the sky daily. The observatory uses the water-Cherenkov detection technique to detect Cherenkov emission from secondary air-shower particles. This study presents improvements to the reconstruction algorithms that retrieve the properties of the primary gamma rays. In particular, the angular resolution and background rejection have improved by a factor of four for gamma-ray events coming from high-zenith angles and with energies above 40 TeV. Thanks to these improvements, HAWC can detect the GC.Although multiple sources of cosmic-ray acceleration to PeV energies, known as PeVatrons, have been proposed within the Galaxy, they remain insufficient to fully account for the observed flux. In this context, the GC was proposed as one of the main Galactic PeVatrons with a power-law spectrum that extends up to 50 TeV without a cutoff. Here, we present, for the first time, observations of gamma rays with energies above 100 TeV, which we suggest originated from PeV protons-accelerated in the GC-that interact with the dense ambient gas. While the angular resolution of HAWC at this high zenith angle is not enough to distinguish the specific PeVatron source, we provide the first confirmation of its existence.The GC is also one of the most promising candidates for indirectly detecting DM via gamma rays. While the nature of DM remains a fundamental question in modern physics, Weakly Interacting Massive Particles (WIMPs) are considered potential candidates for DM and naturally emerge in several extensions of the Standard Model (SM) of particle physics. The relic density of thermally produced WIMPs in the early Universe can account for all the DM observed in the Universe, as measured from cosmological observations. In theory, WIMPs self-annihilate in dense astrophysical environments, like the GC, producing gamma rays in the final state from processes such as hadronization, radiation, and decay of SM particles. We conduct a follow-up study of the above analysis and compare the spatial and spectral morphology of the residual gamma-ray emission to the one theorized for DM annihilation. Finding no significant emission, we place for the first time to date Upper Limits (ULs) at the 95% Confidence Level (CL) on the velocity-weighted cross section, for DM particles with masses well above 70 TeV using GC gamma-ray data.
- 일반주제명
- Astrophysics
- 일반주제명
- Astronomy
- 일반주제명
- Applied physics
- 키워드
- Dark Matter
- 키워드
- Galactic Center
- 키워드
- Pevatron
- 기타저자
- University of Maryland, College Park Physics
- 기본자료저록
- Dissertations Abstracts International. 86-12B.
- 전자적 위치 및 접속
- 로그인 후 원문을 볼 수 있습니다.
MARC
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■006m o d
■007cr#unu||||||||
■020 ▼a9798286437030
■035 ▼a(MiAaPQ)AAI31937681
■040 ▼aMiAaPQ▼cMiAaPQ
■0820 ▼a523
■1001 ▼aYun-Carcamo, Sohyoun.▼0(orcid)0000-0002-9307-0133
■24510▼aObservation of Ultra-High-Energy Gamma Rays and Search for Dark Matter Signatures in the Galactic Center with the HAWC Observatory
■260 ▼a[Sl]▼bUniversity of Maryland, College Park▼c2025
■260 1▼aAnn Arbor▼bProQuest Dissertations & Theses▼c2025
■300 ▼a167 p
■500 ▼aSource: Dissertations Abstracts International, Volume: 86-12, Section: B.
■500 ▼aAdvisor: Goodman, Jordan A.
■5021 ▼aThesis (Ph.D.)--University of Maryland, College Park, 2025.
■520 ▼aThe center of our Galaxy is an intriguing region in astrophysics, providing a unique opportunity to study various astrophysical processes. However, our line of sight is obscured by dense layers of dust and gas, making optical emission observation impossible. Fortunately, we can observe other portions of the electromagnetic spectrum, such as radio, X-rays, and gamma rays. The latter serve as probes of cosmic-ray acceleration to extremely high energies and, in theory, for indirect Dark Matter (DM) detection. This dissertation analyzes gamma-ray data from the Galactic Center (GC), obtained with the High-Altitude Water Cherenkov (HAWC) Gamma-Ray Observatory.The HAWC Observatory, situated on the Sierra Negra volcano in Mexico at an altitude of 4,100 m, detects gamma rays with energies from 0.1 to greater than 100 TeV. It has a wide field of view of about 2 sr, and with an operational duty cycle of over 95%, it observes two-thirds of the sky daily. The observatory uses the water-Cherenkov detection technique to detect Cherenkov emission from secondary air-shower particles. This study presents improvements to the reconstruction algorithms that retrieve the properties of the primary gamma rays. In particular, the angular resolution and background rejection have improved by a factor of four for gamma-ray events coming from high-zenith angles and with energies above 40 TeV. Thanks to these improvements, HAWC can detect the GC.Although multiple sources of cosmic-ray acceleration to PeV energies, known as PeVatrons, have been proposed within the Galaxy, they remain insufficient to fully account for the observed flux. In this context, the GC was proposed as one of the main Galactic PeVatrons with a power-law spectrum that extends up to 50 TeV without a cutoff. Here, we present, for the first time, observations of gamma rays with energies above 100 TeV, which we suggest originated from PeV protons-accelerated in the GC-that interact with the dense ambient gas. While the angular resolution of HAWC at this high zenith angle is not enough to distinguish the specific PeVatron source, we provide the first confirmation of its existence.The GC is also one of the most promising candidates for indirectly detecting DM via gamma rays. While the nature of DM remains a fundamental question in modern physics, Weakly Interacting Massive Particles (WIMPs) are considered potential candidates for DM and naturally emerge in several extensions of the Standard Model (SM) of particle physics. The relic density of thermally produced WIMPs in the early Universe can account for all the DM observed in the Universe, as measured from cosmological observations. In theory, WIMPs self-annihilate in dense astrophysical environments, like the GC, producing gamma rays in the final state from processes such as hadronization, radiation, and decay of SM particles. We conduct a follow-up study of the above analysis and compare the spatial and spectral morphology of the residual gamma-ray emission to the one theorized for DM annihilation. Finding no significant emission, we place for the first time to date Upper Limits (ULs) at the 95% Confidence Level (CL) on the velocity-weighted cross section, for DM particles with masses well above 70 TeV using GC gamma-ray data.
■590 ▼aSchool code: 0117.
■650 4▼aAstrophysics
■650 4▼aAstronomy
■650 4▼aApplied physics
■653 ▼aDark Matter
■653 ▼aGalactic Center
■653 ▼aPower-law spectrum
■653 ▼aPevatron
■653 ▼aGamma-ray emission
■690 ▼a0596
■690 ▼a0606
■690 ▼a0215
■71020▼aUniversity of Maryland, College Park▼bPhysics.
■7730 ▼tDissertations Abstracts International▼g86-12B.
■790 ▼a0117
■791 ▼aPh.D.
■792 ▼a2025
■793 ▼aEnglish
■85640▼uhttp://www.riss.kr/pdu/ddodLink.do?id=T17357025▼nKERIS▼z이 자료의 원문은 한국교육학술정보원에서 제공합니다.
