arXivDaily arXiv每日学术速递 周一至周五更新
arXiv 2404.08052astro-ph.GA
收藏

是静止的还是尘埃笼罩的?揭示$z>3$处极红星系的本质

Quiescent or dusty? Unveiling the nature of extremely red galaxies at $z>3$

L. Barrufet, P. Oesch, R. Marques-Chaves, K. Arellano-Cordova, J. F. W. Baggen, A. C. Carnall, F. Cullen, J. S. Dunlop, R. Gottumukkala, Y. Fudamoto, G. D. Illi… 展开作者

L. Barrufet, P. Oesch, R. Marques-Chaves, K. Arellano-Cordova, J. F. W. Baggen, A. C. Carnall, F. Cullen, J. S. Dunlop, R. Gottumukkala, Y. Fudamoto, G. D. Illingworth, D. Magee, R. J. McLure, D. J. McLeod, M. J. Michałowski, M. Stefanon, P. G. van Dokkum, A. Weibel

AI总结:

本研究利用JWST/NIRSpec首次获取23个z>3处HST暗弱星系的光谱,发现多数为尘埃消光A_V>2mag的尘埃星系,13%为静止星系,且85%为大质量星系,验证了PRISM模式区分星系类型的有效性。

摘要:

詹姆斯·韦伯空间望远镜(JWST)的问世彻底革新了我们对高红移星系的认知。尤其是JWST搭载的近红外相机(NIRCam),发现了一类哈勃空间望远镜(HST)暗弱星系,这类星系此前未被光学波段探测到,原因可能是显著的尘埃消光、星系处于静止状态,或者仅仅是红移极高。本文中,我们展示了23个HST暗弱星系($\text{H-F444W>1.75}$)的首批近红外光谱仪(NIRSpec)光谱,揭示了它们的本质与物理性质。该样本包含尘埃笼罩型和静止型两类星系,其光谱数据来自NIRSpec/PRISM模式,测得的精确光谱红移平均值为$\text{$\bar{z}_{spec}$ = 4.1 ± 0.7}$。光谱特征表明,尽管大多数HST暗弱星系属于尘埃笼罩型,但仍有相当比例($\text{13$^{+9}_{-6}$ \\\\%}$)为静止星系。对于尘埃笼罩型星系,我们利用巴尔末减缩($\text{Hα/ Hβ}$)量化了尘埃消光,测得消光值$\text{A_{V} > 2\\ mag}$。研究发现,尘埃笼罩型HST暗弱星系是Hα发射体,其等值宽度范围为$\text{68 A < EW_{Hα} < 550 A}$,表明近期恒星形成活动的强度范围很广。无论是尘埃笼罩型还是静止型,HST暗弱星系都以大质量为主——样本中85%的星系质量满足$\text{log(M_{*}/M_{\odot}) > 9.8}$。这项NIRSpec先导项目揭示了HST暗弱星系的多样性本质,凸显了NIRSpec/PRISM光谱后续观测在区分尘埃笼罩与静止星系、准确量化其物理性质方面的有效性。未来利用更高分辨率NIRSpec数据、结合JWST与阿塔卡马大型毫米/亚毫米波阵列(ALMA)观测的研究,将深化我们对这些神秘且难以观测的天体的理解。

英文摘要:

The advent of the JWST has revolutionised our understanding of high-redshift galaxies. In particular, the NIRCam instrument on-board JWST has revealed a population of Hubble Space Telescope (HST)-dark galaxies that had previously evaded optical detection, potentially due to significant dust obscuration, quiescence, or simply extreme redshift. Here, we present the first NIRSpec spectra of 23 HST-dark galaxies ($\mathrm{H-F444W>1.75}$), unveiling their nature and physical properties. This sample includes both dusty and quiescent galaxies with spectroscopic data from NIRSpec/PRISM, providing accurate spectroscopic redshifts with $\mathrm{\overline{z}_{spec} = 4.1 \pm 0.7}$. The spectral features demonstrate that, while the majority of HST-dark galaxies are dusty, a substantial fraction, $\mathrm{13^{+9}_{-6} \%}$, are quiescent. For the dusty galaxies, we have quantified the dust attenuation using the Balmer decrement ($\mathrm{Hα/ Hβ}$), finding attenuations $\mathrm{A_{V} > 2\ mag}$. We find that HST-dark dusty galaxies are $\mathrm{Hα}$ emitters with equivalent widths spanning the range $\mathrm{ 68 A < EW_{Hα} < 550 A }$, indicative of a wide range of recent star-formation activity. Whether dusty or quiescent, we find that HST-dark galaxies are predominantly massive, with 85\% of the galaxies in the sample having masses $\mathrm{log(M_{*}/M_{\odot}) > 9.8}$. This pilot NIRSpec program reveals the diverse nature of HST-dark galaxies and highlights the effectiveness of NIRSpec/PRISM spectroscopic follow-up in distinguishing between dusty and quiescent galaxies and properly quantifying their physical properties. Upcoming research utilising higher-resolution NIRSpec data and combining JWST with ALMA observations will enhance our understanding of these enigmatic and challenging sources.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

↑