我们建立了一个模型,从原恒星吸积冲击宇宙线加速,并计算由此产生的宇宙线电离率在恒星形成的分子云。将原星团模型与解析吸积激波模型耦合,计算了宇宙线从原恒星表面的加速。我们提出了宇宙射线通量谱从keV到GeV的能量为一个典型的低质量原恒星。我们发现,在冲击表面的频谱遵循幂律的趋势,在6个数量级的能量。衰减后,高能量下的光谱变陡,而低能量下的光谱相对平坦。利用相对论质子计算了原恒星表面和核心边缘的宇宙线压力和电离率。我们提出的宇宙射线电离率为个别原恒星作为其瞬时质量和最终质量的函数。在吸积激波表面,原恒星宇宙线电离率为$ζ\approx 0.01 - 1$ s $^{-1}$。然而,在核心的边缘,宇宙射线电离率基本上下降到$ζ\approx 10^{-20}$到$10^{-17}$ s $^{-1}$之间。宇宙射线电离率存在较大的空间梯度,使得内部区域可能经历大于通常假设的基准率$ζ= 3\times10^{-17}$ s $^{-1}$的宇宙射线电离率。最后,我们计算了5个数量级以上的原恒星团的宇宙线电离率。我们发现,超过约200个原恒星的集群产生更高的宇宙射线电离率在其出生的云比基准银河值。
英文摘要:
We construct a model for cosmic ray acceleration from protostellar accretion shocks and calculate the resulting cosmic ray ionization rate within star-forming molecular clouds. We couple a protostar cluster model with an analytic accretion shock model to calculate the cosmic ray acceleration from protostellar surfaces. We present the cosmic ray flux spectrum from keV to GeV energies for a typical low-mass protostar. We find that at the shock surface the spectrum follows a power-law trend across 6 orders of magnitude in energy. After attenuation, the spectrum at high energies steepens, while at low energies it is relatively flat. We calculate the cosmic ray pressure and cosmic ray ionization rate from relativistic protons at the protostellar surface and at the edge of the core. We present the cosmic ray ionization rate for individual protostars as a function of their instantaneous mass and final mass. The protostellar cosmic ray ionization rate is $ζ\approx 0.01 - 1$ s$^{-1}$ at the accretion shock surface. However, at the edge of the core, the cosmic ray ionization rate drops substantially to between $ζ\approx 10^{-20}$ to $10^{-17}$ s$^{-1}$. There is a large spatial gradient in the cosmic ray ionization rate, such that inner regions may experience cosmic ray ionization rates larger than the often assumed fiducial rate, $ζ= 3\times10^{-17}$ s$^{-1}$. Finally, we calculate the cosmic ray ionization rate for protostellar clusters over 5 orders of magnitude of cluster size. We find that clusters with more than approximately 200 protostars produce a higher cosmic ray ionization rate within their natal cloud than the fiducial galactic value.
The initial conditions of stellar protocluster formation. II. A catalogue of starless and protostellar clumps embedded in IRDCs in the Galactic longitude range 15<l<55
Tracking Protostellar Variability in Massive Protoclusters with ALMA: I. Insights from QUARKS and MaMMOtH
Shanghai Astronomical Observatory, Chinese Academy of Sciences(中国科学院上海天文台);School of Astronomy and Space Sciences, University of Chinese Academy of Sciences(中国科学院大学天文与空间科学学院);State Key Laboratory of Radio Astronomy and Technology, Shanghai Astronomical Observatory, Chinese Academy of Sciences(中国科学院上海天文台射电天文学与技术国家重点实验室);Institute of Astronomy and Astrophysics, Academia Sinica(中央研究院天文及天文物理研究所);NRC Herzberg Astronomy and Astrophysics(加拿国家研究委员会赫茨伯格天体物理学研究所);Department of Physics and Astronomy, University of Victoria(维多利亚大学物理与天文系);Kavli Institute for Astronomy and Astrophysics, Peking University(北京大学卡尔·萨根天文与天体物理研究所);Department of Astronomy, Peking University(北京大学天文系)
Evidence of Enhanced Ionization in Protostellar Envelopes
Max-Planck-Institut für Astronomie(马克斯·普朗克天文学研究所);Steward Observatory, University of Arizona(亚利桑那大学斯图尔德天文台);Univ. Grenoble Alpes, CNRS, IPAG(格勒诺布尔阿尔卑斯大学、法国国家科学研究中心、地球与行星物理学研究所);Max-Planck-Institut für Radioastronomie(马克斯·普朗克射电天文学研究所);Laboratoire d’Astrophysique (AIM) Université Paris-Saclay, Université Paris Cité, CEA, CNRS, AIM(巴黎萨克雷大学、巴黎西岱大学、法国原子能和替代能源委员会、法国国家科学研究中心天体分子实验室);INAF, Osservatorio Astrofisico di Arcetri(意大利国家天体物理研究所阿切尔天文台)
ATOMS-QUARKS survey: Inflow and infall in massive protocluster G318.049+00.086: Evidence of competitive accretion
Indian Institute of Astrophysics(印度天体物理研究所);Pondicherry University(本地治里大学);S.N. Bose National Centre for Basic Sciences(S.N. 玻色基础科学国家中心);Shanghai Astronomical Observatory, Chinese Academy of Sciences(中国科学院上海天文台);Max Planck Institute for Astronomy(马克斯·普朗克天文学研究所);Korea Astronomy and Space Science Institute(韩国天文与空间科学研究所);University of Science and Technology(科学技术大学);Chinese Academy of Sciences South America Center for Astronomy, National Astronomical Observatories, CAS(中国科学院国家天文台南美天文中心)
A nine-member protostellar system forming via filament fragmentation in the high mass protocluster NGC 6334-43
Scottish Universities Physics Alliance (SUPA), School of Physics and Astronomy, University of St Andrews(圣安德鲁斯大学物理与天文学学院);National Radio Astronomy Observatory(国家射电天文台);Massachusetts Institute of Technology(麻省理工学院);Aberystwyth University(阿伯里斯特威斯大学)
The ALMA Survey of 70 $μ\rm m$ Dark High-mass Clumps in Early Stages (ASHES). II: Molecular Outflows in the Extreme Early Stages of Protocluster Formation
Discovery of a Compact Hub-Filament System in G286.21+0.17 with JWST and ALMA: Insights into Protocluster Formation and Competitive Accretion
Peking University(北京大学);National Astronomical Research Institute of Thailand(泰国国家天文研究所);Gifu University(岐阜大学);Indian Institute of Technology Gandhinagar(甘地纳加尔印度理工学院);Korea Astronomy and Space Science Institute(韩国天文学与宇宙科学研究所);University of Science and Technology, Korea (UST)(韩国科学技术院);Jet Propulsion Laboratory, California Institute of Technology(加州理工学院喷气推进实验室);Nazarbayev University(纳扎尔巴耶夫大学)
The double signature of local cosmic-ray acceleration in star-forming regions
近年来,人们对原恒星表面或沿原恒星喷流的激波产生低能宇宙射线(< 1 TeV)的研究越来越感兴趣。这些局部加速的CR提供了一个有吸引力的解释,高水平的非热发射和电离率,$ζ$,观察接近这些来源。在一些原恒星源中观察到的高$ζ$通常归因于激波产生的紫外光子。本文的目的是表明,当在同一空间区域测量同步辐射和高$ζ$时,局部冲击加速的CR通量足以解释这两种现象。假设相对论粒子按一阶费米加速机制加速,计算了$ζ$和厘米波段的非热辐射。然后,我们将我们的模型应用到恒星形成区域OMC-2 FIR 3/FIR 4。使用贝叶斯分析,我们约束模型的参数和估计的光谱指数的非热无线电发射。我们证明,本地CR加速模型,使它有可能同时解释同步辐射沿HOPS 370喷流在FIR 3区域和$ζ$附近观察到的FIR 4原星团。我们的模型约束的磁场强度(~250-450 $~μ$ G),其湍流分量(~20-40 $~μ$ G),并为HOPS 370喷流(~350-1000 km s $^{-1}$)的三个非热源的冲击参考系中的喷流速度。除了OMC-2 FIR 3/FIR 4系统的建模,我们展示了如何在厘米波长和分子跃迁的连续观测的组合是一个强大的新工具,用于分析恒星形成区域:这两种类型的观测可以同时解释调用只存在局部加速CR,而不必诉诸冲击产生的UV光子。
Radiative Feedback in Population III Protostellar Growth: HI Shielding and HII Region Trapping
Rutgers, The State University of New Jersey(新泽西州立大学罗格斯分校);Flatiron Institute(平顿研究所);Leiden University(莱顿大学);UCLA(加州大学洛杉矶分校);The University of Tokyo(东京大学)