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Molecular Gas and Star Formation in Nearby Galaxy Centers
Molecular Gas and Star Formation in Nearby Galaxy Centers
상세정보
- 자료유형
- 학위논문 서양
- 최종처리일시
- 20250211151508
- ISBN
- 9798383209035
- DDC
- 523
- 저자명
- Teng, Yu-Hsuan.
- 서명/저자
- Molecular Gas and Star Formation in Nearby Galaxy Centers
- 발행사항
- [Sl] : University of California, San Diego, 2024
- 발행사항
- Ann Arbor : ProQuest Dissertations & Theses, 2024
- 형태사항
- 225 p
- 주기사항
- Source: Dissertations Abstracts International, Volume: 86-01, Section: B.
- 주기사항
- Advisor: Sandstrom, Karin M.
- 학위논문주기
- Thesis (Ph.D.)--University of California, San Diego, 2024.
- 초록/해제
- 요약Star formation in galaxies is governed by the amount of molecular gas and the efficiency that gas is converted into stars. However, assessing the amount of molecular gas relies on the CO-to-H2 conversion factor (\uD835\uDEFCCO), which is known to vary with molecular gas conditions like density, temperature, and dynamical state - the same conditions that also alter star formation efficiency. The variation of \uD835\uDEFCCO, particularly in galaxy centers where \uD835\uDEFCCO can drop by nearly an order of magnitude, thus causes major uncertainties in current molecular gas and star formation efficiency measurements. Using ALMA observations of multiple low-\uD835\uDC3D 12CO, 13CO, and C18O lines in several barred galaxy centers, we found that \uD835\uDEFCCO is primarily driven by CO opacity changes and therefore shows strong correlations with observables like velocity dispersion and 12CO/13CO line ratio. Motivated by these results, we have constructed a new \uD835\uDEFCCO prescription which accounts for emissivity effects in galaxy centers and verified it on a set of barred and non-barred galaxies with measured \uD835\uDEFCCO values from dust. Applying our new prescription to 65 galaxies from the PHANGS-ALMA survey, we found an overall three times higher star formation efficiency in barred galaxy centers than in non-barred galaxy centers, and such a trend is obscured when using a constant \uD835\uDEFCCO or other existing prescriptions. Our results suggest that the high star formation rate observed in barred galaxy centers is due to an enhanced star formation efficiency compared to non-barred galaxy centers or the disk regions, rather than a substantially increased amount of molecular gas in barred galaxy centers.
- 일반주제명
- Astrophysics
- 일반주제명
- Astronomy
- 일반주제명
- Physics
- 키워드
- Star formation
- 키워드
- Galaxies
- 키워드
- Molecular gas
- 기타저자
- University of California, San Diego Physics
- 기본자료저록
- Dissertations Abstracts International. 86-01B.
- 전자적 위치 및 접속
- 로그인 후 원문을 볼 수 있습니다.
MARC
008250123s2024 us c eng d■001000017161965
■00520250211151508
■006m o d
■007cr#unu||||||||
■020 ▼a9798383209035
■035 ▼a(MiAaPQ)AAI31299328
■040 ▼aMiAaPQ▼cMiAaPQ
■0820 ▼a523
■1001 ▼aTeng, Yu-Hsuan.
■24510▼aMolecular Gas and Star Formation in Nearby Galaxy Centers
■260 ▼a[Sl]▼bUniversity of California, San Diego▼c2024
■260 1▼aAnn Arbor▼bProQuest Dissertations & Theses▼c2024
■300 ▼a225 p
■500 ▼aSource: Dissertations Abstracts International, Volume: 86-01, Section: B.
■500 ▼aAdvisor: Sandstrom, Karin M.
■5021 ▼aThesis (Ph.D.)--University of California, San Diego, 2024.
■520 ▼aStar formation in galaxies is governed by the amount of molecular gas and the efficiency that gas is converted into stars. However, assessing the amount of molecular gas relies on the CO-to-H2 conversion factor (\uD835\uDEFCCO), which is known to vary with molecular gas conditions like density, temperature, and dynamical state - the same conditions that also alter star formation efficiency. The variation of \uD835\uDEFCCO, particularly in galaxy centers where \uD835\uDEFCCO can drop by nearly an order of magnitude, thus causes major uncertainties in current molecular gas and star formation efficiency measurements. Using ALMA observations of multiple low-\uD835\uDC3D 12CO, 13CO, and C18O lines in several barred galaxy centers, we found that \uD835\uDEFCCO is primarily driven by CO opacity changes and therefore shows strong correlations with observables like velocity dispersion and 12CO/13CO line ratio. Motivated by these results, we have constructed a new \uD835\uDEFCCO prescription which accounts for emissivity effects in galaxy centers and verified it on a set of barred and non-barred galaxies with measured \uD835\uDEFCCO values from dust. Applying our new prescription to 65 galaxies from the PHANGS-ALMA survey, we found an overall three times higher star formation efficiency in barred galaxy centers than in non-barred galaxy centers, and such a trend is obscured when using a constant \uD835\uDEFCCO or other existing prescriptions. Our results suggest that the high star formation rate observed in barred galaxy centers is due to an enhanced star formation efficiency compared to non-barred galaxy centers or the disk regions, rather than a substantially increased amount of molecular gas in barred galaxy centers.
■590 ▼aSchool code: 0033.
■650 4▼aAstrophysics
■650 4▼aAstronomy
■650 4▼aPhysics
■653 ▼aStar formation
■653 ▼aGalaxies
■653 ▼aMolecular gas
■653 ▼aEmissivity effects
■690 ▼a0596
■690 ▼a0606
■690 ▼a0605
■71020▼aUniversity of California, San Diego▼bPhysics.
■7730 ▼tDissertations Abstracts International▼g86-01B.
■790 ▼a0033
■791 ▼aPh.D.
■792 ▼a2024
■793 ▼aEnglish
■85640▼uhttp://www.riss.kr/pdu/ddodLink.do?id=T17161965▼nKERIS▼z이 자료의 원문은 한국교육학술정보원에서 제공합니다.
