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arXiv 2510.04771astro-ph.GA
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在Abell S1063后方z=7-9处的Hβ+[OIII]λλ4960,5008光度函数极 faint 端的初步观察

A GLIMPSE into the very faint-end of the H$β$+[OIII]$λλ$4960,5008 luminosity function at z=7-9 behind Abell S1063

Observatoire de Genève, Université de Genève(日内瓦天文台,日内瓦大学);Institut d’Astrophysique de Paris, CNRS, Sorbonne Université(巴黎天体物理研究所,法国国家科学研究中心,索邦大学);Department of Physics, Ben-Gurion University of the Negev(内盖夫本-古里安大学物理系);Department of Astronomy, The University of Texas at Austin(德克萨斯大学奥斯汀分校天文学系);CNRS, IRAP(法国国家科学研究中心,天体物理研究所);Department of Astronomy, Oskar Klein Centre, Stockholm University(斯德哥尔摩大学奥斯卡·克莱因中心天文学系)
Damien Korber, Iryna Chemerynska, Lukas J. Furtak, Hakim Atek, Ryan Endsley, Daniel Schaerer, John Chisholm, Vasily Kokorev, Alberto Saldana-Lopez, Angela Adamo… 展开作者

Damien Korber, Iryna Chemerynska, Lukas J. Furtak, Hakim Atek, Ryan Endsley, Daniel Schaerer, John Chisholm, Vasily Kokorev, Alberto Saldana-Lopez, Angela Adamo, Julian B. Muñoz, Pascal A. Oesch, Romain Meyer, Rui Marques-Chaves, Seiji Fujimoto

AI总结:

利用GLIMPSE调查研究z=7-9处Abell S1063后方Hβ+[OIII]光度函数的极 faint 端,通过SED拟合分析恒星形成历史和金属丰度对光度函数的影响,发现低金属丰度和爆发性恒星形成可解释光度函数差异。

摘要:

我们利用超深GLIMPSE JWST/NIRCam调查来约束z=7-9处Abell S1063后方Hβ+[OIII]λλ4960,5008光度函数(LF)的极 faint 端,至10^39 erg/s。我们对Lyman-break星系样本进行SED拟合,测量综合Hβ+[OIII]流量以构建发射线LF。所得到的LF(α=-1.55到-1.78)比UV LF(α<-2)更平坦,表明在固定MUV下低Hβ+[OIII]发射体的数目密度较低。我们探讨了三种解释:(i)爆发性恒星形成历史降低Hβ+[OIII]-到UV比率,(ii)金属丰度对[OIII]/Hβ的影响,或(iii)UV LF的极 faint 端转折。假设一个演化的[OIII]/Hβ比率,我们得出一个更平坦的[OIII]λ5008 LF(α=-1.45到-1.66)和一个更陡峭的Hβ LF(α=-1.68到-1.95)。假设低金属丰度和爆发性恒星形成可以解释UV和Hβ+[OIII] LF的差异。将LF转换为离子化光子生产率,发现Hα流量>10^39 erg/s(SFR(Hα)>5×10^-3 M_太阳/年)的星系在7<z<8和8<z<9范围内分别贡献31%-90%和46%-156%的离子化光子预算(对于f_esc=0.14)。LF形状表明,微弱星系对离子化光子生产率贡献极小。我们的宇宙恒星形成率密度(CSFRD)估计与先前工作一致,但GLIMPSE对低SFR的敏感性证实极微弱星系对离子化光子生产率和CSFRD都是次要贡献者。我们的结果表明,GLIMPSE已检测到大部分恒星形成星系的总Hβ+[OIII]发射,更微弱的源在宇宙再电离中作用有限。

英文摘要:

We use the ultra-deep GLIMPSE JWST/NIRCam survey to constrain the faint-end of the H$β$+[OIII]$λλ$4960,5008 luminosity function (LF) down to $10^{39}$ erg/s at z=7-9 behind the lensed Hubble Frontier Field Abell S1063. We perform SED fitting on a Lyman-Break Galaxy sample, measuring combined H$β$+[OIII] fluxes to construct the emission-line LF. The resulting LF ($α$=-1.55 to -1.78) is flatter than the UV LF ($α<-2$), indicating a lower number density of low H$β$+[OIII] emitters at fixed MUV. We explore three explanations: (i) bursty star formation histories reducing the H$β$+[OIII]-to-UV ratio, (ii) metallicity effects on [OIII]/H$β$, or (iii) a faint-end turnover in the UV LF. Assuming an evolving [OIII]/H$β$ ratio, we derive a flatter [OIII]$λ$5008 LF ($α$=-1.45 to -1.66) and a steeper H$β$ LF ($α$=-1.68 to -1.95). The combination of decreasing metallicity and bursty star formation can reconcile the UV and H$β$+[OIII] LF differences. Converting the LF to the ionising photon production rate, we find that galaxies with H$α$ flux $>10^{39}$ erg/s (SFR(H$α$)$>5\times10^{-3} M_\odot$/yr) contribute 31%-90% and 46%-156% of the ionising photon budget at 7<z<8 and 8<z<9, respectively (for $f_{esc}=0.14$). The LF shape suggests faint galaxies contribute minimally to the ionising photon production rate. Our cosmic star formation rate density (CSFRD) estimates align with previous work, but GLIMPSE's sensitivity to low SFRs confirms that very faint galaxies are minor contributors to both the ionising photon production rate and the CSFRD. Our results suggest that GLIMPSE has detected the bulk of the total H$β$+[OIII] emission from star-forming galaxies, with fainter sources playing a limited role in cosmic reionisation.

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