Galaxy Structure as a Driver of the Star Formation Sequence Slope and Scatter
Katherine E. Whitaker, Marijn Franx, Rachel Bezanson, Gabriel B. Brammer, Pieter G. van Dokkum, Mariska T. Kriek, Ivo Labbe, Joel Leja, Ivelina G. Momcheva, Eri… 展开作者
Katherine E. Whitaker, Marijn Franx, Rachel Bezanson, Gabriel B. Brammer, Pieter G. van Dokkum, Mariska T. Kriek, Ivo Labbe, Joel Leja, Ivelina G. Momcheva, Erica J. Nelson, Jane R. Rigby, Hans-Walter Rix, Rosalind E. Skelton, Arjen van der Wel, Stijn Wuyts
It is well established that (1) star-forming galaxies follow a relation between their star formation rate (SFR) and stellar mass (M$_{\star}$), the "star-formation sequence", and (2) the SFRs of galaxies correlate with their structure, where star-forming galaxies are less concentrated than quiescent galaxies at fixed mass. Here, we consider whether the scatter and slope of the star-formation sequence is correlated with systematic variations in the Sersic indices, $n$, of galaxies across the SFR-M$_{\star}$ plane. We use a mass-complete sample of 23,848 galaxies at $0.5<z<2.5$ selected from the 3D-HST photometric catalogs. Galaxy light profiles parameterized by $n$ are based on Hubble Space Telescope CANDELS near-infrared imaging. We use a single SFR indicator empirically-calibrated from stacks of Spitzer/MIPS 24$μ$m imaging, adding the unobscured and obscured star formation. We find that the scatter of the star-formation sequence is related in part to galaxy structure; the scatter due to variations in $n$ at fixed mass for star-forming galaxies ranges from 0.14$\pm$0.02 dex at $z\sim2$ to 0.30$\pm$0.04 dex at $z<1$. While the slope of the log(SFR)-log(M$_{\star}$) relation is of order unity for disk-like galaxies, galaxies with $n>2$ (implying more dominant bulges) have significantly lower SFR/M$_{\star}$ than the main ridgeline of the star-formation sequence. These results suggest that bulges in massive $z\sim2$ galaxies are actively building up, where the stars in the central concentration are relatively young. At $z<1$, the presence of older bulges within star-forming galaxies lowers global SFR/M$_{\star}$, decreasing the slope and contributing significantly to the scatter of the star-formation sequence.
The slope and scatter of the star forming main sequence at z~5 : reconciling observations with simulations
Institute of Science and Technology Austria (ISTA)（奥地利科学技术研究所）；MIT Kavli Institute for Astrophysics and Space Research, Massachusetts Institute of Technology（麻省理工学院卡弗里天体物理与空间研究所）；Universite Claude Bernard Lyon 1, CRAL UMR5574, ENS de Lyon, CNRS（里昂第一大学，CRAL UMR5574，里昂高等师范学校，法国国家科学研究中心）；Institute for Computational & Data Sciences, The Pennsylvania State University（宾夕法尼亚州立大学计算与数据科学研究所）；Institute for Gravitation and the Cosmos, The Pennsylvania State University（宾夕法尼亚州立大学引力与宇宙学研究所）；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）
A break in the high-redshift stellar mass Tully-Fisher relation
本文研究了恒星质量与气体速度色散积分之间的Tully-Fisher关系（TFR），该关系由运动学估计量S_0.5量化，由星系光谱中0<z<5的强发射线测量。我们将光度选择的星系（“高光度样本”）与以其他方式选择的星系（“低光度样本"）结合起来，以覆盖几乎跨越五个数量级的恒星质量范围：7.0 < log M* < 11.5。我们发现，对数幂律斜率和归一化的TFR是独立的红移到z~3。TFR的离散度为<0.5 dex such that the gas velocity dispersion can be used as a proxy for the stellar mass of a galaxy independently of its redshift. At z>3，离散度增大，相关性不明显。在z<3时，高光度样品的斜率为1.5 $\pm$ 0.2，而低光度样品的斜率为2.9 $\pm$ 0.3，这表明TFR发生了转换。合并后的样本与TFR在M*~10 $^{10}$ M $_{\odot}$的特征恒星质量标度处的突变很好地拟合，没有显著的演化到z~3。我们证明，TFR在低质量端出现斜率更陡的突变是具有质量依赖性恒星与晕质量比的星系模型的自然结果。
Hitting the slopes: A spectroscopic view of UV continuum slopes of galaxies reveals a reddening at z > 9.5
University of Oxford（牛津大学）；University College London（伦敦大学学院）；University of Chicago（芝加哥大学）；Kavli Institute for Cosmological Physics, University of Chicago（芝加哥大学卡弗里宇宙物理学研究所）；University of Cambridge（剑桥大学）；Kavli Institute for Cosmology, University of Cambridge（剑桥大学卡弗里宇宙学研究所）；Cavendish Laboratory, University of Cambridge（剑桥大学卡文迪许实验室）；Centro de Astrobiología (CAB), CSIC–INTA（西班牙国家航空航天技术研究所与西班牙国家科学研究委员会联合天体生物学中心）；European Space Agency（欧洲航天局）
