Caught in the act: gas and stellar velocity dispersions in a fast quenching compact star-forming galaxy at z~1.7
G. Barro, S. M. Faber, A. Dekel, C. Pacifici, P. G. Perez-Gonzalez, E. Toloba, D. C. Koo, J. R. Trump, S. Inoue, Y. Guo, F. Liu, J. R. Primack, A. M. Koekemoer,… 展开作者
G. Barro, S. M. Faber, A. Dekel, C. Pacifici, P. G. Perez-Gonzalez, E. Toloba, D. C. Koo, J. R. Trump, S. Inoue, Y. Guo, F. Liu, J. R. Primack, A. M. Koekemoer, G. Brammer, A. Cava, N. Cardiel, D. Ceverino, C. M. Eliche, J. J. Fang, S. L. Finkelstein, D. D. Kocevski, R. C. Livermore, E. McGrath
我们介绍了GDN-8231的Y和H波段的Mask-I MOSFIRE光谱，GDN-8231是一个大质量、致密的恒星形成星系（SFG），红移为$z\sim1.7$。它的光谱揭示了H $_α$和[NII]发射线以及强的巴耳末吸收线。H $_α$和斯皮策MIPS 24 $μ$ m通量都很弱，因此表明SFR $\lesssim5-10$ M $_{\odot}$ yr $^{-1}$的恒星形成率很低。再加上从吸收线测量到的$\sim700$ Myr相对年轻的年龄，这为遥远的星系在快速关闭其恒星形成过程中被捕获提供了第一个直接证据。这样的淬灭使得GDN-8231成为一个紧凑的，静止的星系，类似于我们样本中的其他3个星系，通过$z\sim1.5$。此外，GDN-8231的颜色分布显示出更蓝的中心，与最近模拟的由内而外淬灭早期阶段的预测一致。它的气体视线速度色散$σ^{\rm{gas}}_{\!_{\rm LOS}}=127\pm32$ km s $^{-1}$比它的恒星$σ^{\star}_{\!_{\rm LOS}}=215\pm35$ km s $^{-1}$小近40%。星系的高分辨率流体模拟解释了这种明显较冷的气体运动学的$\sim1.5$的一个因素与旋转盘被认为是在不同的倾角和/或集中的恒星形成区域。一个明确的预测是，它们紧凑、静止的后代保留了一些来自恒星形成祖先的残余旋转。
英文摘要：
We present Keck-I MOSFIRE spectroscopy in the Y and H bands of GDN-8231, a massive, compact, star-forming galaxy (SFG) at a redshift $z\sim1.7$. Its spectrum reveals both H$_α$ and [NII] emission lines and strong Balmer absorption lines. The H$_α$ and Spitzer MIPS 24 $μ$m fluxes are both weak, thus indicating a low star formation rate of SFR $\lesssim5-10$ M$_{\odot}$ yr$^{-1}$. This, added to a relatively young age of $\sim700$ Myr measured from the absorption lines, provides the first direct evidence for a distant galaxy being caught in the act of rapidly shutting down its star formation. Such quenching allows GDN-8231 to become a compact, quiescent galaxy, similar to 3 other galaxies in our sample, by $z\sim1.5$. Moreover, the color profile of GDN-8231 shows a bluer center, consistent with the predictions of recent simulations for an early phase of inside-out quenching. Its line-of-sight velocity dispersion for the gas, $σ^{\rm{gas}}_{\!_{\rm LOS}}=127\pm32$ km s$^{-1}$, is nearly 40% smaller than that of its stars, $σ^{\star}_{\!_{\rm LOS}}=215\pm35$ km s$^{-1}$. High-resolution hydro-simulations of galaxies explain such apparently colder gas kinematics of up to a factor of $\sim1.5$ with rotating disks being viewed at different inclinations and/or centrally concentrated star-forming regions. A clear prediction is that their compact, quiescent descendants preserve some remnant rotation from their star-forming progenitors.
Ram-pressure stripping caught in action in a young cluster at $z = 2.51$
Nanjing University（南京大学）；Key Laboratory of Modern Astronomy and Astrophysics, Nanjing University（南京大学现代天文与天体物理重点实验室）；Université Paris-Saclay（巴黎萨克雷大学）；Université Paris Cité（巴黎西岱大学）；CEA（法国原子能和替代能源委员会）；CNRS（法国国家科学研究中心）；AIM（宇宙学、物质与星际介质研究所）；Pontificia Universidad Católica de Valparaíso（智利天主教瓦帕拉索大学）；Istituto Nazionale di Astrofisica (INAF)（意大利国家天体物理研究所）；Purple Mountain Observatory, Chinese Academy of Sciences（中国科学院紫金山天文台）
We characterize the chemical and physical conditions in an outflowing high-velocity cloud in the inner Galaxy. We report a super-solar metallicity of [O/H] = $+0.36\pm0.12$ for the high-velocity cloud at $v_\mathrm{LSR}$ = 125.6 km s$^{-1}$ toward the star HD 156359 ($l$ = 328.$^{\circ}$7, $b$ = $-$14.$^{\circ}$5, $d$ = 9 kpc, $z$ = $-$2.3 kpc). Using archival observations from FUSE, HST STIS, and ESO FEROS we measure high-velocity absorption in H I, O I, C II, N II, Si II, Ca II, Si III, Fe III, C IV, Si IV, N V, and O VI. We measure a low H I column density of log $N$(H I) = $15.54\pm0.05$ i…
Leo I is considered one of the youngest dwarf spheroidals (dSph) in the Local Group. Its isolation, extended star formation history (SFH), and recent perigalacticon passage (~1 Gyr ago) make Leo~I one of the most interesting nearby stellar systems. Here, we analyse deep photometric Hubble Space Telescope data via colour-magnitude diagram fitting techniques to study its global and radially-resolved SFH. We find global star formation enhancements in Leo I ~13, 5.5, 2.0, and 1.0 Gyr ago, after which it was substantially quenched. Within the context of previous works focused on Leo I, we interpret…
Although it is generally accepted that massive galaxies form in a two-phased fashion, beginning with a rapid mass buildup through intense starburst activities, followed by primarily dry mergers that mainly deposit stellar mass at outskirts, the late time stellar mass growth of brightest cluster galaxies (BCGs), the most massive galaxies in the universe, is still not well understood. Several independent measurements have indicated a slower mass growth rate than predictions from theoretical models. We attempt to resolve the discrepancy by measuring the frequency of BCGs with multiple-cores, whic…
We used the Atacama Large Millimeter/submillimeter Array (ALMA) to map $^{12}$CO($J$ = 1-0), $^{12}$CO($J$ = 2-1), $^{12}$CO($J$ = 3-2), $^{13}$CO($J$ = 2-1), and [CI]($^3P_1$-$^3P_0$) emission lines around the type 1 active galactic nucleus (AGN) of NGC 7469 ($z = 0.0164$) at $\sim 100$ pc resolutions. The CO lines are bright both in the circumnuclear disk (central $\sim 300$ pc) and the surrounding starburst (SB) ring ($\sim 1$ kpc diameter), with two bright peaks on either side of the AGN. By contrast, the [CI]($^3P_1$-$^3P_0$) line is strongly peaked on the AGN. Consequently, the brightnes…
The VEGAS imaging survey of the Hydra I cluster reveals an extended network of stellar filaments to the south-west of the spiral galaxy NGC3314A. Within these filaments, at a projected distance of ~40 kpc from the galaxy, we discover an ultra-diffuse galaxy (UDG) with a central surface brightness of $μ_{0,g}\sim26$ mag arcsec$^{-2}$ and effective radius $R_e\sim3.8$ kpc. This UDG, named UDG32, is one of the faintest and most diffuse low-surface brightness galaxies in the Hydra~I cluster. Based on the available data, we cannot exclude that this object is just seen in projection on top of the st…
Close encounters between young stellar objects in star forming clusters are expected to dramatically perturb circumstellar disks. Such events are witnessed in numerical simulations of star formation, but few direct observations of ongoing encounters have been made. Here we report sub-0".1 resolution Atacama Large Millimeter Array (ALMA) and Jansky Very Large Array (JVLA) observations towards the million year old binary protostar Z CMa in dust continuum and molecular line emission. A point source ~4700 au from the binary has been discovered at both millimeter and centimeter wavelengths. It is l…
Quenching is a key topic in exploring the formation and evolution of galaxies. In this work, we study the quenching rate, i.e., the variation in the fraction of quenched galaxies per unit time, of the Illustris-1 simulation. By building the quenched fraction function $f(m,ρ, t)$ of each snapshot in the simulation, we derive an accurate form of quenching rate as $\Re_q=df(m,ρ,t)/dt$. According to the analytic expression of the quenching rate $\Re_q$, we split it into four components: mass quenching, environmental quenching, intrinsic mass quenching and intrinsic environmental quenching. The pre…
We investigate the role of galaxy mergers on supermassive black hole (SMBH) accretion and star formation quenching in three state-of-the-art cosmological simulations with contrasting physics models: EAGLE, Illustris and IllustrisTNG. We find that recently coalesced 'post-mergers' in all three simulations have elevated SMBH accretion rates by factors of ~2-5. However, rapid (within 500 Myr of coalescence) quenching of star formation is rare, with incidence rates of 0.4% in Illustris, 4.5% in EAGLE and 10% in IllustrisTNG. The rarity of quenching in post-mergers results from substantial gas rese…
Several mechanisms for the transformation of blue star-forming to red quiescent galaxies have been proposed, and the green valley (GV) galaxies amid them are widely accepted in a transitional phase. Thus, comparing the morphological and environmental differences of the GV galaxies with early-type disks (ETDs; bulge dominated and having a disk) and late-type disks (LTDs; disk dominated) is suitable for distinguishing the corresponding quenching mechanisms. A large population of massive ($M_* \geqslant 10^{10}M_\odot$) GV galaxies at $0.5 \leqslant z \leqslant 1.5$ in 3D-HST/CANDELS is selected …
Caught in the act: interaction-driven evolution in the nearby compact galaxy group Roberts Quartet (SCG0018-4854)
Indian Institute of Astrophysics（印度天体物理研究所）；Department of Physics, Pondicherry University（本地治里大学物理系）；Department of Physics, University of Allahabad（阿拉哈巴德大学物理系）
We study the incidence of nuclear activity in a large sample of massive post-starburst galaxies at z~0.7 selected from the Sloan Digital Sky Survey, and identify active galactic nuclei based on radio continuum and optical emission lines. Over our mass range of 10^10.6-10^11.5 Msun, the incidence of radio activity is weakly dependent on stellar mass and independent of stellar age, while radio luminosity depends strongly on stellar mass. Optical nuclear activity incidence depends most strongly on the Dn4000 line index, a proxy for stellar age, with an active fraction that is ~ten times higher in…
Significance of bar quenching in the global quenching of star formation
在棒斑盘星系的千秒差距内，由于棒斑的作用，恒星形成受到抑制，这种现象被称为棒斑猝灭。我们在这里调查的酒吧淬火的意义，在全球淬火的恒星形成的棒星系和它们的转变，在本地宇宙的被动星系。我们这样做是通过测量恒星形成率-恒星质量平面中的淬火棒星系与恒星形成主序星星系的偏移量，并将其与棒的长度进行比较，这被认为是棒淬火的代理。我们构造了银河动物园所确认的2885个本地宇宙正面强棒盘星系（$z<0.06$）的恒星形成率-恒星质量平面。这里研究的棒斑盘星系落在恒星形成的主序星关系上，对于恒星质量大于10 $^{10.2}$ M $\odot$的星系有显著的散射。我们发现34.97个$\%$星系在主序星关系的内禀散射（0.3 dex）范围内，其中10.78个$\%$（高于0.3 dex）星爆星群和54.25个$\%$（低于-0.3 dex）猝灭星群。在淬熄棒星系中检测到大量的中性氢（M $_{HI}$ >10 $^{9}$ M $\odot$，log M $_{HI}$ /M $\star$ $\sim$ -1.0 to -0.5），其气体含量与恒星形成棒星系相似。我们发现淬熄棒星系偏离主序星关系的偏移量不依赖于恒星棒的长度。这意味着棒淬灭可能对棒星系中恒星形成的整体淬灭没有显著贡献。然而，这种观察到的结果也可能是由于其他因素，例如在星形形成淬火后随着时间的推移棒的溶解，同时作用的其他淬火过程的影…
We present a multiwavelength study of IC 860, a nearby post-starburst galaxy at the early stage of transitioning from blue and star-forming to red and quiescent. Optical images reveal a galaxy-wide, dusty outflow originating from a compact core. We find evidence for a multiphase outflow in the molecular and neutral gas phase from the CO position-velocity diagram and NaD absorption features. We constrain the neutral mass outflow rate to be ~0.5 M$_{\odot}/$yr, and the total hydrogen mass outflow rate to be ~12 M$_{\odot}$/yr. Neither outflow component seems able to escape the galaxy. We also fi…
First results on the cluster galaxy population from the Subaru Hyper Suprime-Cam survey. I. The role of group or cluster environment in star formation quenching from z = 0.2 to 1.1
Investigating quenching in Recently Quenched Elliptical galaxies with HI studies
University of Missouri-Kansas City（密苏里大学堪萨斯城分校）；Arecibo Observatory, NAIC（阿雷西博天文台，北美星际与电离层中心）；University of Minnesota, Twin Cities（明尼苏达大学双城分校）；National Centre for Radio Astrophysics, Tata Institute of Fundamental Research（国家射电天体物理中心，塔塔基础研究所）
Dissecting the mass quenching in TNG50: Galaxy size determines the quenching mode
University of Science and Technology of China（中国科学技术大学）；Peking University（北京大学）；Durham University（杜伦大学）；Institute of Deep Space Sciences, Deep Space Exploration Laboratory（深空科学研究所，深空探测实验室）
A SHARP Look at Quenching and Bulge-Disk Growth in Massive Galaxies at Cosmic Noon
INAF - Istituto di Astrofisica Spaziale e Fisica Cosmica, Milano（意大利国家天体物理研究所空间天体物理学与宇宙学天文台，米兰）；INAF - Osservatorio Astronomico di Paodva（意大利国家天体物理研究所帕多瓦天文台）；Université Paris-Saclay, Université Paris Cité, CEA, CNRS, AIM（巴黎萨克雷大学、巴黎西岱大学、法国原子能和替代能源委员会、法国国家科学研究中心、天体物理学信息与方法实验室）；CEA Saclay, DFR/IRFU, Service d’Astrophysique（法国原子能和替代能源委员会萨克雷中心核研究与物理研究所天体物理服务部）；INAF - Osservatorio Astronomico di Arcetri（意大利国家天体物理研究所阿切特里天文台）；INAF - Osservatorio Astronomico di Brera（意大利国家天体物理研究所布雷拉天文台）；Department of Physics, Oxford University（牛津大学物理系）
The phenomenological study of evolving galaxy populations has shown that star forming galaxies can be quenched by two distinct processes: mass quenching and environment quenching (Peng et al. 2010). To explore the mass quenching process in local galaxies, we study the massive central disk galaxies with stellar mass above the Schechter characteristic mass. In Zhang et al. (2019), we showed that during the quenching of the massive central disk galaxies as their star formation rate (SFR) decreases, their molecular gas mass and star formation efficiency drop rapidly, but their HI gas mass remains …
We investigate the influence of active galactic nucleus (AGN) feedback on the galaxy cold gas content and its connection to galaxy quenching in three hydrodynamical simulations of Illustris, IllustrisTNG and SIMBA. By comparing to the observed atomic and molecular neutral hydrogen measurements for central galaxies, we find that Illustris over-predicts the cold gas masses in star-forming galaxies and significantly under-predicts them for quenched galaxies. IllustrisTNG performs better in this comparison than Illustris, but quenched galaxies retain too much cold gas compared with observations. S…
The underlying nature of the process of star formation quenching in the central regions of barred disc galaxies that is due to the action of stellar bar is not fully understood. We present a multi-wavelength study of four barred galaxies using the archival data from optical, ultraviolet, infrared, CO, and HI imaging data on star formation progression and stellar and gas distribution to better understand the process of bar quenching. We found that for three galaxies, the region between the nuclear or central sub-kiloparsec region and the end of the bar (bar region) is devoid of neutral and mole…
The mechanisms that bring galaxies to strongly reduce their star formation activity (star-formation quenching) is still poorly understood. To better study galaxy evolution, we propose a classification based on the maps of the ionised hydrogen distribution, traced by kpc-resolved, equivalent width of H$α$ maps, and the nuclear activity of the galaxies using information from the BPT diagnostic diagrams. Using these tools, we group a sample of 238 galaxies from the CALIFA survey in six quenching stages (QS): objects dominated by recent star formation; systems that present a quiescent-nuclear-ring…
Satellite quenching and morphological transformation of galaxies in groups and clusters
Department of Physics and Astronomy, McMaster University（麦克马斯特大学物理与天文学系）；NAT-Universidade Cidade de São Paulo（圣保罗城市大学）；School of Physics and Astronomy, University of Nottingham（诺丁汉大学物理与天文学院）
To explore the effect of environment on star-formation and morphological transformation of high-redshift galaxies, we present a robust estimation of localized galaxy overdensity using a density estimator within the Bayesian probability framework.The maps of environmental overdensity at $0.5< z< 2.5$ are constructed for the five CANDELS fields. In general, the quiescent fraction increases with overdensity and stellar mass. Stellar mass dominates the star formation quenching for massive galaxies, while environmental quenching tends to be more effective for the low-mass galaxies at $0.5< z < 1$. …
We study complete sample of spiral galaxies brighter than M$_{\mathrm{B}} \sim$-18.4 in three Abell clusters: A85 ($z=\,$0.055), A496 ($z=\,$0.033) and A2670 ($z=\,$0.076). This work is based on a large volume limited, blind Hi-survey (21cm, NRAO-VLA), on optical imaging (CFHT) and on the search for dynamical substructures. Our goal is to explore the effects of local environment on the HI gas properties and this, in turn, on the star formation activity and quenching of individual galaxies. We report significant differences among the HI properties of these clusters and we discuss the role playe…
Galaxy mergers are traditionally one of the favoured mechanisms for quenching star formation. To test this paradigm in the context of modern cosmological simulations, we use the IllustrisTNG simulation to investigate the impact of individual merger events on quenching (i.e. star formation rate at least 3sig below the star-forming main sequence) within 500Myr after the coalescence phase.The rate of quenching amongst recently merged galaxies is compared with a control sample that is matched in redshift, stellar mass, star formation rate (SFR), black hole mass and environment.We find quenching to…
