[TCA Student Seminar] The Magnetic Field in Star-Forming Regions of the Perseus Molecular Cloud
The NCTS Astrophysics group (TG2.3) is holding the monthly student seminar series. These provide opportunities for the domestic students to share their work and practice giving live talks.
Please find the schedule listed in the tabulation below. Each seminar starts at 12 p.m. and takes place in the NCTS Physics 4F Lecture Hall, Cosmology Hall, NTU.
For more detailed information regarding each seminar, please see it in the section below the tabulation a week before the seminar.
| Date | Speaker 1 | Affiliation | Supervisor | Speaker 2 | Affiliation | Supervisor |
| 2025/7/24 | Pon-Yin Wang | TKU | Hsi-An Pan | |||
| 2025/8/22 | Tsung-Han Chuang | NTNU | Yueh-Ning Lee | Jyun-Heng Lin | NTHU/ASIAA | Chin-Fei Lee |
| 2025/9/26 | Chiung-Yin Chang | NTHU | Hsiang-Yi Karen Yang | Huan-Ping Chao | NCKU | Kwan-Lok Li |
| 2025/10/31 | Yi-Yang Lee | NTHU | Hsiang-Yi Karen Yang | Prangsutip Cherdwongsung | NTHU | Ing-Guey Jiang |
| 2025/11/28 | Yu-Xuan Nancy Lin | NYCU | Shih-Ping Lai | |||
| 2025/12/26 | Szu-Ting Chen | NTHU | Shin-Ping Lai |
Time: 2025/12/26 (Fri.) 12:00-12:30
Place: NCTS Physics 4F Lecture Hall, Cosmology Hall, NTU
Talk Title: The Magnetic Field in Star-Forming Regions of the Perseus Molecular Cloud
Speaker: Szu-Ting Chen (NTHU)
Abstract:
To understand the influence of magnetic fields on star formation processes, we estimated the magnetic field strength in IC348, L1448, L1455, NGC1333, and B1 of the Perseus molecular cloud using the Davis–Chandrasekhar–Fermi (DCF) method and its modified approaches. The angular dispersion was derived from 850 μm polarization data observed by the JCMT, while velocity dispersion was measured from N2H+ (1–0) and NH3 (1,1) spectral lines observed with the NRO and the GBT, respectively. The average plane-of-sky magnetic field strength calculated by the DCF method is around a few hundred μG, consistently higher than those obtained using the modified methods. Nevertheless, the observed mass-to-flux ratio with all the methods shows a transition from subcritical in filaments to supercritical in the cores, suggesting that cores initially form in subcritical environments before evolving into supercritical ones. In addition, all regions exhibit sub-Alfvénic or trans-Alfvénic conditions, indicating that magnetic fields dominate over turbulence. We further find that nonthermal FWHM derived from N2H+ are systematically broader than those from NH3 by an average of 0.1 km/s, suggesting that NH3 may trace inner regions within the cloud. Simple modeling of filamentary structure shows that such linewidth differences can arise from tracing distinct density regimes, while the NH3/N2H+ abundance ratio remains constant. To assess the relative importance of magnetic fields, gravity, and turbulence, we calculated energy budgets for prestellar and protostellar cores. Our results show that gravitational energy becomes increasingly dominant over magnetic energy in the denser regions traced by NH3. These findings align with the ambipolar diffusion model, indicating a weakening magnetic field and increasing gravitational dominance toward core centers.
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