arXivDaily arXiv每日学术速递 周一至周五更新
arXiv 2201.04270astro-ph.GA
收藏

Z~2.3日下金属丰度星系的IR SED和尘埃质量

IR SED and Dust Masses of Sub-solar Metallicity Galaxies at z~2.3

Irene Shivaei, Gergö Popping, George Rieke, Naveen Reddy, Alexandra Pope, Robert Kennicutt, Bahram Mobasher, Alison Coil, Yoshinobu Fudamoto, Mariska Kriek, Jia… 展开作者

Irene Shivaei, Gergö Popping, George Rieke, Naveen Reddy, Alexandra Pope, Robert Kennicutt, Bahram Mobasher, Alison Coil, Yoshinobu Fudamoto, Mariska Kriek, Jianwei Lyu, Pascal Oesch, Ryan Sanders, Alice Shapley, Brian Siana

摘要:

我们目前的结果从ALMA 1.2毫米连续观测的样本27恒星形成星系z=2.1-2.5的MOSFIRE深演化场(MOSDEF)调查。这些星系有来自Hb、[OIII]、Ha和[NII]的气相金属丰度和恒星形成率测量。利用Spitzer、Herschel和ALMA测光(静止坐标系~ 8-400 $μ$ m)的叠加,我们研究了高红移太阳下金属丰度(~0.5 $Z_{\odot}$)LIRGs的IR SED。我们发现,数据吻合得很好的平均SED模板较高的光度本地低金属丰度矮星系(减少$χ^2$的1.8)。当与太阳金属丰度本星系或高红移LIRG和ULIRG的常用模板比较时,即使在最有利的情况下(约化的$χ^2$为2.8),模板也在>98%的置信水平下被拒绝。本地矮星系和高红移太阳下金属丰度星系的更广泛和更热的IR SED可能是由于不同的颗粒特性,尘埃几何形状,或更硬/更强的电离辐射场将尘埃加热到更高的温度。太阳下金属丰度星系的远红外辐射所指示的遮蔽SFR仅占总SFR的约60%,远低于局部LIRG的遮蔽分数(约96-97%)。由于演变的IR SED形状,拟合到中IR数据的局部LIRG模板可能高估z~2处的瑞利-金斯尾测量值2-20倍,并且如果拟合到观测到的ALMA通量,则这些模板低估IR光度>0.4dex。在给定的恒星质量或金属丰度下,z~2.3处的尘埃质量比z~0处的尘埃质量高一个数量级。考虑到预测的分子气体质量分数,观测到的z~2.3的尘埃-恒星质量比表明,在相同的金属丰度下,尘埃-分子气体质量比本地星系低。

英文摘要:

We present results from ALMA 1.2mm continuum observations of a sample of 27 star-forming galaxies at z=2.1-2.5 from the MOSFIRE Deep Evolution Field (MOSDEF) survey. These galaxies have gas-phase metallicity and star-formation rate measurements from Hb, [OIII], Ha, and [NII]. Using stacks of Spitzer, Herschel, and ALMA photometry (rest-frame ~ 8-400$μ$m), we examine the IR SED of high-redshift subsolar metallicity (~0.5 $Z_{\odot}$) LIRGs. We find that the data agree well with an average SED template of higher luminosity local low-metallicity dwarf galaxies (reduced $χ^2$ of 1.8). When compared with the commonly used templates for solar-metallicity local galaxies or high-redshift LIRGs and ULIRGs, even in the most favorable case (with reduced $χ^2$ of 2.8), the templates are rejected at >98% confidence level. The broader and hotter IR SED of both the local dwarfs and high-redshift subsolar metallicity galaxies may result from different grain properties, a clumpy dust geometry, or a harder/more intense ionizing radiation field that heats the dust to higher temperatures. The obscured SFR indicated by the FIR emission of the subsolar metallicity galaxies is only ~ 60% of the total SFR, which is considerably lower than that of the local LIRGs with ~ 96-97% obscured fractions. Due to the evolving IR SED shape, the local LIRG templates fit to mid-IR data can overestimate the Rayleigh-Jeans tail measurements at z~2 by a factor of 2-20, and these templates underestimate IR luminosities if fit to the observed ALMA fluxes by >0.4dex. At a given stellar mass or metallicity, dust masses at z~2.3 are an order of magnitude higher than those at z~0. Given the predicted molecular gas mass fractions, the observed z~2.3 dust-to-stellar mass ratios suggest lower dust-to-molecular gas masses than in local galaxies at the same metallicity.

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。

↑