AI 中文总结
本研究利用JWST的NIRCam和MIRI数据，制作了小麦哲伦星系NGC 346迄今最深的近中红外测光星表，表征了其不同恒星族群，为后续研究提供基础。
AI 中文摘要
NGC 346是一个位于约62千秒差距（kpc）处的大质量恒星形成区，地处小麦哲伦星系（SMC）。由于其金属丰度较低（Z约为太阳金属丰度的1/5），它是研究类似宇宙正午时期的恒星形成与恒星族群的理想环境。本研究中，我们制作了NGC 346的詹姆斯·韦伯空间望远镜（JWST）近红外相机（NIRCam）和中红外仪器（MIRI）的联合测光星表。我们对该区域的不同恒星族群进行了表征：主序上星（UMS）、红巨星支（RGB）、红团簇星（RC），以及前主序星（pre-MS）和年轻恒星天体（YSOs）。我们在NIRCam和MIRI的11个波长波段中进行了点扩散函数（PSF）加权测光，并利用多张色-星等图来识别该天区的各类恒星族群。我们最终得到的NGC 346测光星表包含249519个独特源，其中包括2024颗主序上星、2755颗红巨星支星和742颗红团簇星。此外，我们识别出6274颗候选前主序星、7350颗候选年轻恒星天体和23819颗红外超量源。将这三类源结合，我们表征出1583个强候选前主序星/年轻恒星天体和3761个可能的候选前主序星/年轻恒星天体。通过利用F115W-F200W对F115W-F187N的色-色图，我们发现239个非虚假源具有Paα超量，表明NGC 346中存在吸积过程和恒星形成活动。利用JWST的NIRCam和MIRI观测，我们制作了恒星形成区NGC 346在近红外至中红外波段（1-21微米）迄今为止最深的星表。我们的星表及对年轻和年老恒星族群的表征将为后续详细研究提供基础。
英文摘要
NGC 346 is a massive star-forming region located at a distance of $\sim$62 kpc, in the Small Magellanic Cloud (SMC). Due to its low metallicity (Z $\sim$1/5 Z$_{\odot}$), it is an ideal environment to study star formation and stellar population analogues to those at Cosmic Noon. In this work, we produce a combined JWST NIRCam and MIRI photometric catalogue of NGC 346. We characterise different stellar populations in the region: the upper main sequence (UMS), red giant branch (RGB), and red clump (RC), as well as pre-main sequence (pre-MS) stars and young stellar objects (YSOs). We performed point-spread function (PSF) weighted photometry in 11 wavelength bands across NIRCam and MIRI and utilised multiple colour-magnitude-diagrams to identify the various stellar populations in the field. Our final photometric catalogue of NGC 346 comprises 249,519 unique sources, including 2,024 UMS stars, 2,755 RGB stars and 742 RC stars. In addition, we identified 6,274 candidate pre-MS stars, 7,350 candidate YSOs and 23,819 IR-excess sources. Combining these three categories, we characterised 1,583 strong and 3,761 likely pre-MS/YSO candidates. By utilising the F115W-F200W vs F115W-F187N colour-colour diagram, we found 239 non-spurious sources with Pa$α$ excess, indicating accretion and star formation in NGC 346. Using JWST NIRCam and MIRI observations, we produced the deepest catalogue to date of the star formation region NGC 346 in the near- and mid-IR range (1-21$~μ$m). Our catalogue and characterisations of the young and old populations will provide the basis for detailed follow-up studies.
CommentsPaper accepted to The Astrophysical Journal Supplement Series, 34 pages, 13 figures
