Compact Star-Forming Galaxies as Old Starbursts Becoming Quiescent
C. Gómez-Guijarro, G. E. Magdis, F. Valentino, S. Toft, A. W. S. Man, R. J. Ivison, K. Tisanić, D. van der Vlugt, M. Stockmann, S. Martin-Alvarez, G. Brammer
Optically-compact star-forming galaxies (SFGs) have been proposed as immediate progenitors of quiescent galaxies, although their origin and nature are debated. Were they formed in slow secular processes or in rapid merger-driven starbursts? Addressing this question would provide fundamental insight into how quenching occurs. We explore the location of the general population of galaxies with respect to fundamental star-forming and structural relations, identify compact SFGs based on their stellar core densities, and study three diagnostics of the burstiness of star formation: 1) Star formation efficiency, 2) interstellar medium (ISM), and 3) radio emission. The overall distribution of galaxies in the fundamental relations points towards a smooth transition towards quiescence while galaxies grow their stellar cores, although some galaxies suddenly increase their specific star-formation rate when they become compact. From their star formation efficiencies compact and extended SFGs appear similar. In relation to the ISM diagnostic, by studying the CO excitation, the density of the neutral gas, and the strength of the ultraviolet radiation field, compact SFGs resemble galaxies located in the upper envelope of the SFGs main sequence, although yet based on a small sample size. Regarding the radio emission diagnostic we find that galaxies become increasingly compact as the starburst ages, implying that at least some compact SFGs are old starbursts. We suggest that compact SFGs could be starburts winding down and eventually crossing the main sequence towards quiescence.
We present structural measurements of 145 spectroscopically selected intermediate-redshift (z$\sim$0.7), massive ($M_\star \sim 10^{11} \ M_\odot$) post-starburst galaxies from the SQuIGG$\vec{L}$E Sample measured using wide-depth Hyper Suprime-Cam i-band imaging. This deep imaging allows us to probe the sizes and structures of these galaxies, which we compare to a control sample of star forming and quiescent galaxies drawn from the LEGA-C Survey. We find that post-starburst galaxies systematically lie $\sim0.1$ dex below the quiescent mass-size (half-light radius) relation, with a scatter of …
Galaxy And Mass Assembly (GAMA): The mechanisms for quiescent galaxy formation at $z<1$
天体物理学的一个关键问题是理解星系如何以及为什么关闭它们的恒星形成，建立我们在本地宇宙中观察到的静态人口。从GAMA和VIPERS调查，我们使用光谱指数来选择静止和候选过渡星系。我们确定潜在的快速过渡后星暴星系，和较慢的过渡绿谷星系。在过去的8个Gyr中，静止星群在高质量（M $_*>10^{11}$ M $_\odot$）时的数量密度增长比在中等质量（M $_*>10^{10.6}$ M $_\odot$）时慢。在后星暴和绿谷恒星质量函数中都有演化，这与早期宇宙时期质量更高的星系淬火相一致。在中等质量（M $_*>10^{10.6}$ M $_\odot$），我们发现一个绿谷过渡时间尺度为2.6 Gyr。或者，在$z\sim0.7$，整个增长率可以用快速猝灭的星暴后星系来解释，其可见度时间尺度为0.5 Gyr。在较低的红移下，后恒星暴增的数量密度是如此之低，以至于需要一个非物理性的短可见度窗口才能对静止的人口增长做出显着贡献。在$z<1$，快速淬灭途径的重要性可能会迅速降低。然而，在高质量（M $_*>10^{11}$ M $_\odot$），有大量的候选过渡星系之间的张力相比，静止人口的缓慢增长。如果不是所有的高质量后星暴星系和绿谷星系都从恒星形成过渡到静止，例如如果它们在气体吸积和触发恒星形成后从静止的人口中恢复活力，或者如果它们未能完全熄灭它们的恒星形成，那么这个问题就可以…
A Large Population of Massive Compact Post-Starburst Galaxies at z>1: Implications for the Size Evolution and Quenching Mechanism of Quiescent Galaxies
我们通过一个0<z<2的年轻和年老静止星系样本的数密度和结构演化来研究红色序列的增长。这些星系是从宇宙演化巡天（COSMOS）领域的NEWFIRM中带巡天（NMBS）中选出的。我们发现了大量的大质量年轻星系，这些星系在z>1时刚刚熄灭（“后星爆”），而在z<1时几乎不存在;它们的数密度在z=2时为5 x 10^{-5} Mpc^{-3}，而在z=0.5时要小10倍。在z>1时，观测到的年轻和年老静止星系的数密度与一个简单的模型相一致，在这个模型中，所有年老静止星系都曾被认为是后星暴星系。我们发现，总体人口的静止星系有较小的尺寸和略长的形状在较高的红移，与其他最近的研究。有趣的是，最近在1<z<2处淬灭的星系并不比那些红移的老星系大，甚至可能更小。这一结果与静止星系的平均大小的演化主要是由较大的恒星形成星系的连续转变驱动的观点不一致：在这种情况下，最年轻的静止星系也是最大的。相反，合并或其他机制似乎需要解释从z=2到现在的静止星系的大小增长。
JWST PRIMER: Post-starburst galaxies dominate the low-mass quiescent galaxy population since z~2
University of Nottingham（诺丁汉大学）；University of St Andrews（圣安德鲁斯大学）；University of Edinburgh（爱丁堡大学）；Johns Hopkins University（约翰斯·霍普金斯大学）；Space Telescope Science Institute（太空望远镜科学研究所）
Recent observations have successfully detected [O III] $88.3\,{\rm μm}$ and [C II] $157.6\,{\rm μm}$ lines from galaxies in the early Universe with the Atacama Large Millimeter Array (ALMA). Combining cosmological hydrodynamic simulations and radiative transfer calculations, we present relations between the metal line emission and galaxy evolution at $z=6-15$. We find that galaxies during their starburst phases have high [O III] luminosity of $\sim 10^{42}~\rm erg~s^{-1}$. Once supernova feedback quenches star formation, [O III] luminosities rapidly decrease and continue to be zero for $\sim 1…
This Letter examines how the sizes, structures, and color gradients of galaxies change along the quiescent sequence. Our sample consists of ~400 quiescent galaxies at $1.0\le z\le2.5$ and $10.1 \le \log{M_*/M_\odot}\le11.6$ in three CANDELS fields. We exploit deep multi-band HST imaging to derive accurate mass profiles and color gradients, then use an empirical calibration from rest-frame UVJ colors to estimate galaxy ages. We find that -- contrary to previous results -- the youngest quiescent galaxies are not significantly smaller than older quiescent galaxies at fixed stellar mass. These `po…
Tidal Disruption Events (TDEs) have been found to show a preference for post-starburst (PS) and quiescent Balmer-strong (QBS) galaxies. This preference can be used to help find TDEs in transient surveys. But what other transients might "contaminate" such a search, and by how much? We examine all reported transients coincident with the centers of galaxies in the French & Zabludoff (2018) catalog of spectroscopically confirmed PS and QBS galaxies and photometrically identified PS and QBS galaxy candidates. We find that TDEs and Type Ia supernovae (SNe) are the only types of transients classified…
We present morphological analyses of Post-starburst galaxies (PSBs) at $0.7<z<0.9$ in the COSMOS field. We fitted ultraviolet to mid-infrared multi-band photometry of objects with $i<24$ from COSMOS2020 catalogue with population synthesis models assuming non-parametric, piece-wise constant function of star formation history, and selected 94 those galaxies that have high specific star formation rates (SSFRs) of more than $10^{-9.5}$ yr$^{-1}$ in 321--1000 Myr before observation and an order of magnitude lower SSFRs within recent 321 Myr. We devised a new non-parametric morphological index which…
The GOLIATH Survey: OVI Absorption Reveals CGM Evolution through the Starburst-to-Quiescent Transition in Massive Galaxies
North Carolina State University（北卡罗来纳州立大学）；Space Telescope Science Institute（太空望远镜科学研究所）；University of Notre Dame（圣母大学）；University of Colorado（科罗拉多大学）；New Mexico State University（新墨西哥州立大学）；University of South Carolina（南卡罗来纳大学）
We use deep, spatially resolved spectroscopy from the LEGA-C Survey to study radial variations in the stellar population of 17 spectroscopically-selected post-starburst (PSB) galaxies. We use spectral fitting to measure two Lick indices, $Hδ_A$ and $Fe4383$, and find that, on average, PSB galaxies have radially decreasing $Hδ_A$ and increasing $Fe4383$ profiles. In contrast, a control sample of quiescent, non-PSB galaxies in the same mass range shows outwardly increasing $Hδ_A$ and decreasing $Fe4383$. The observed gradients are weak ($\approx-0.2$ Å/$R_e$), mainly due to seeing convolution. A…
We present a photometric analysis of star and star cluster (SC) formation in a high-resolution simulation of a dwarf galaxy starburst that allows the formation of individual stars to be followed. Previous work demonstrated that the properties of the SCs formed in the simulation are in good agreement with observations. In this paper, we create mock spectral energy distributions and broad-band photometric images using the radiative transfer code SKIRT 9. We test several observational star formation rate (SFR) tracers and find that $24$ $μ$m, total infrared and H$α$ trace the underlying SFR durin…
Sub-kpc ALMA imaging of compact star-forming galaxies at z~2.5: revealing the formation of dense galactic cores in the progenitors of compact quiescent galaxies
我们目前的空间分辨阿塔卡马大毫米/亚毫米阵列（ALMA）870 $μ$米尘埃连续图的6个大规模，紧凑，尘埃恒星形成星系（SFG）在$z\sim2.5$。这些星系被选中是因为它们的小静止坐标系光学尺寸（$r_{\rm e, F160W}\sim1.6$ kpc）和高恒星质量密度，这表明它们是$z\sim2$致密静止星系的直接祖先。深源观测得到了L $_{\rm IR}=10^{12.3-12.8}$ L $_{\odot}$的高远红外光度和SFR $=200-700$ M $_{\odot}$ yr $^{-1}$的高恒星形成率，与典型的恒星形成“主序星”星系一致。高空间分辨率（FWHMPDMATHABMU0.12”-0.18”）ALMA和HST测光相结合，构造了它们的恒星质量和（UV+IR）SFR的去卷积平均径向轮廓。我们发现，尘埃，核IR-SFR压倒性地占主导地位的辐射热SFR高达$r\sim5$千秒差距，超过100 $\times$的一个因素，从unobscured UV-SFR。此外，平均SFR剖面的有效半径（$r_{\rm e, SFR}\sim1$ kpc）比恒星质量剖面的有效半径小30%。如果这样的核星爆持续了估计的$Δt=\pm100$ Myr的气体耗尽时间，那么隐含的结构演化是中心1 kpc内恒星质量密度增加4 $\times$，半质量半径减少1.6 $\times…
Post-starburst galaxies (PSBs) have recently and rapidly quenched their star-formation, thus they are an important way to understand how galaxies transition from star-forming late-types to quiescent early-types. The recent discovery of large cold gas reservoirs in PSBs calls into question the theory that galaxies must lose their gas to become quiescent. Optical Integral Field Spectroscopy (IFS) surveys have revealed two classes of PSBs: central PSBs with central quenching regions and ring PSBs with quenching in their outskirts. We analyze a sample of 13 nearby (z < 0.1) PSBs with spatially res…
Using the IllustrisTNG cosmological galaxy formation simulations, we analyze the physical properties of young quiescent galaxies at z=2 with stellar masses above 10^10.5 solar masses. This key population provides an unaltered probe into the evolution of galaxies from star-forming to quiescent and has been recently targeted by several observational studies. Young quiescent galaxies in the simulations do not appear unusually compact, in tension with observations, but they show unique age gradients that are qualitatively consistent with the observed color gradients. In particular, more than half …
A Dusty Quenching-candidate AGN host at z=5.7: massive quiescent galaxies may quench already during the dust-obscured phase
University of Cambridge（剑桥大学）；University College London（伦敦大学学院）；University of Trieste（的里雅斯特大学）；National Astronomical Observatories (NAOC)（国家天文台）；University of Chinese Academy of Sciences（中国科学院大学）；University of Groningen（格罗宁根大学）
We present a measurement of the intrinsic space density of intermediate redshift ($z\sim0.5$), massive ($M_{*} \sim 10^{11} \ \text{M}_{\odot}$), compact ($R_{e} \sim 100$ pc) starburst ($Σ_{SFR} \sim 1000 \ \text{M}_{\odot} \ \text{yr}^{-1} \text{kpc}^{-1}$) galaxies with tidal features indicative of them having undergone recent major mergers. A subset of them host kiloparsec scale, $>1000 \ \text{km}\ \text{s}^{-1}$ outflows and have little indication of AGN activity, suggesting that extreme star formation can be a primary driver of large-scale feedback. The aim for this paper is to calculat…
We present the first study of the large-scale clustering of post-starburst (PSB) galaxies in the high redshift Universe ($0.5<z<3.0$). We select $\sim4000$ PSB galaxies photometrically, the largest high-redshift sample of this kind, from two deep large-scale near-infrared surveys: the UKIDSS Ultra Deep Survey (UDS) DR11 and the Cosmic Evolution Survey (COSMOS). Using angular cross-correlation techniques, we estimate the halo masses for this large sample of PSB galaxies and compare them with quiescent and star-forming galaxies selected in the same fields. We find that low-mass, low-redshift ($0…
Identifying Tidal Disruption Events via Prior Photometric Selection of Their Preferred Hosts
在星暴后的星系或其他具有强烈巴耳末吸收的静止星系中检测到的核瞬变很可能是潮汐破裂事件（TDE）。在大型综合巡天望远镜（LSST）的计划调查足迹内识别这些星系-在检测到瞬变之前-将使TDE分类立即和后续更有效。不幸的是，大多数这类星系的光谱都是不可用的，简单的光度选择是无效的;切割“绿谷”紫外/光学/红外颜色产生的样品是高度污染和不完整的。在这里，我们提出了一个新的策略，只使用光度光学/UV/IR数据从大型调查。将机器学习随机森林分类器应用于GALEX和WISE测光的~ 400 k SDSS星系样本，包括13，592个静态Balmer强星系，我们获得了53-61%的纯度和8-21%的完整性，给出了红移范围。对于1299个恒星暴增后星系的子集，我们实现了63-73%的纯度和5-12%的完整性。考虑到这些结果，可能的TDE和超新星发生率的范围，以及36-75%的TDE发生在静止的Balmer强宿主中，我们估计在光度选择的宿主星系中观察到的瞬变中有13-99%将是TDE，并且我们将发现LSST每年119-248个TDE。使用我们的技术，我们提出了一个新的目录67,484候选星系预计有一个高的TDE率，从SDSS，泛星，DES和WISE测光调查。这个样本比目前SDSS的类似星系样本大3.5倍，从而为瞬态科学和星系演化研究提供了一条新的前进道路。
Tracing Radio AGN-Driven Quenching in Post-Starburst Galaxies at Cosmic Noon
Johns Hopkins University（约翰斯·霍普金斯大学）；Space Telescope Science Institute（太空望远镜科学研究所）；AURA for ESA, Space Telescope Science Institute（欧洲空间局阿雷西博大学协会太空望远镜科学研究所）；University of Nottingham（诺丁汉大学）；University of St Andrews（圣安德鲁斯大学）；University of Edinburgh（爱丁堡大学）；European Southern Observatory (ESO)（欧洲南方天文台）
We study the co-evolution between the black hole accretion rate (BHAR) and the star formation rate (SFR) in different galaxy life phases: main sequence star-forming galaxies, quiescent and starburst galaxies at different cosmic epochs. We take advantage of the X-ray data from the Chandra COSMOS-Legacy survey and of the extensive multiwavelength ancillary observations in the COSMOS field presented in the COSMOS2015 catalog. We perform an X-ray stacking analysis and combine it with detected sources, in a broad redshift interval ($0.1<z<3.5$). The X-ray luminosity is used to predict the BHAR, whi…
We report a massive quiescent galaxy at $z_{\rm spec}=3.0922^{+0.008}_{-0.004}$ spectroscopically confirmed at a protocluster in the SSA22 field by detecting the Balmer and Ca {\footnotesize II} absorption features with multi-object spectrometer for infrared exploration (MOSFIRE) on the Keck I telescope. This is the most distant quiescent galaxy confirmed in a protocluster to date. We fit the optical to mid-infrared photometry and spectrum simultaneously with spectral energy distribution (SED) models of parametric and nonparametric star formation histories (SFH). Both models fit the observed S…
We report the discovery of BOSS-EUVLG1 at z=2.469, by far the most luminous, almost un-obscured star-forming galaxy known at any redshift. First classified as a QSO within the Baryon Oscillation Spectroscopic Survey, follow-up observations with the Gran Telescopio Canarias reveal that its large luminosity, MUV = -24.40 and log(L_Lya/erg s-1) = 44.0, is due to an intense burst of star-formation, and not to an AGN or gravitational lensing. BOSS-EUVLG1 is a compact (reff = 1.2 kpc), young (4-5 Myr) starburst with a stellar mass log(M*/Msun) = 10.0 +/- 0.1 and a prodigious star formation rate of ~…
We present a sample of 151 massive ($M_* > 10^{10}\mathrm{M_\odot}$) quiescent galaxies at $2 < z < 5$, based on a sophisticated Bayesian spectral energy distribution fitting analysis of the CANDELS UDS and GOODS-South fields. Our sample includes a robust sub-sample of 61 objects for which we confidently exclude low-redshift and star-forming solutions. We identify 10 robust objects at $z>3$, of which 2 are at $z>4$. We report formation redshifts, demonstrating that the oldest objects formed at $z > 6$, however individual ages from our photometric data have significant uncertainties, typically …
