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arXiv 2002.07189astro-ph.GA
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大质量星系质量函数从$z$ =1.5到0.4的(缺)演化

On the (Lack of) Evolution of the Stellar Mass Function of Massive Galaxies from $z$=1.5 to 0.4

Lalitwadee Kawinwanichakij, Casey Papovich, Robin Ciardullo, Steven L. Finkelstein, Matthew L. Stevans, Isak G. Wold, Shardha Jogee, Sydney Sherman, Jonathan Florez, Caryl Gronwall

摘要:

本文研究了$0.4<z<1.5$(覆盖9 Gyr)上最大质量星系数密度的演化。我们使用斯皮策/HETDEX探索性大面积(SHELA)调查,其中包括17.5 $\mathrm{deg}^2$与8个光度带跨越0.3-4.5 $μ$米的SDSS条纹82字段内。这个尺寸产生了最低的计数不确定性和宇宙方差,但在$z\sim1.0$的大质量星系。我们研究的恒星质量函数(SMF)的星系与$\log(M_\ast/M_\odot)>10.3$使用的前向建模方法,充分考虑统计和系统的不确定性恒星质量。从$z$ =0.4到1.5,SMF的大质量端在其形状上显示出最小的演变:特征质量($M^\ast$)的进化小于0.1 dex(PDMATHAMT 0.05 dex);具有$\log (M_\ast/M_\odot) >11$的星系的数量密度大致保持在$\log (n/\mathrm{Mpc}^{-3})$ $\simeq$ $-$ 3.4($\pm$ 0.05),然后在PDMATHAMR =1.5时下降至$\log (n/\mathrm{Mpc}^{-3})$ = $-$ 3.7($\pm$ 0.05)。我们讨论了SMF中的不确定性,主要是在恒星形成历史和恒星质量估计的恒星人口合成模型的细节的假设。对于静止星系,数据是一致的,没有(或轻微)的演变($\lesssim0.1$ dex)的特征质量,也没有数密度从$z\sim 1.5$到现在。这意味着任何静止的大质量星系群的质量增长(可能是通过“干”合并)必须平衡恒星演化后期的质量损失率和恒星形成群体形成淬灭星系的速度。我们提供了从$z=1.0$到0.4的$ΔM_\ast/M_\ast\leq$ 45%的这种质量增长的限制(即,$\simeq0.16$ dex),用于比$10^{11}$ $M_\odot$质量更大的静止星系。

英文摘要:

We study the evolution in the number density of the highest mass galaxies over $0.4<z<1.5$ (covering 9 Gyr). We use the Spitzer/HETDEX Exploratory Large-Area (SHELA) Survey, which covers 17.5 $\mathrm{deg}^2$ with eight photometric bands spanning 0.3-4.5 $μ$m within the SDSS Stripe 82 field. This size produces the lowest counting uncertainties and cosmic variance yet for massive galaxies at $z\sim1.0$. We study the stellar mass function (SMF) for galaxies with $\log(M_\ast/M_\odot)>10.3$ using a forward-modeling method that fully accounts for statistical and systematic uncertainties on stellar mass. From $z$=0.4 to 1.5 the massive end of the SMF shows minimal evolution in its shape: the characteristic mass ($M^\ast$) evolves by less than 0.1 dex ($\pm$0.05 dex); the number density of galaxies with $\log (M_\ast/M_\odot) >11$ stays roughly constant at $\log (n/\mathrm{Mpc}^{-3})$ $\simeq$ $-$3.4 ($\pm$0.05), then declines to $\log (n/\mathrm{Mpc}^{-3})$=$-$3.7 ($\pm$0.05) at $z$=1.5. We discuss the uncertainties in the SMF, which are dominated by assumptions in the star formation history and details of stellar population synthesis models for stellar mass estimations. For quiescent galaxies, the data are consistent with no (or slight) evolution ($\lesssim0.1$ dex) in the characteristic mass nor number density from $z\sim 1.5$ to the present. This implies that any mass growth (presumably through "dry" mergers) of the quiescent massive galaxy population must balance the rate of mass losses from late-stage stellar evolution and the formation of quenching galaxies from the star-forming population. We provide a limit on this mass growth from $z=1.0$ to 0.4 of $ΔM_\ast/M_\ast\leq$ 45% (i.e., $\simeq0.16$ dex) for quiescent galaxies more massive than $10^{11}$ $M_\odot$.

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