We propose to use relative strengths of far-infrared fine structure lines from galaxies to characterise early phases of the inside-out quenching by massive black holes (BHs). The BH feedback is thought to quench star formation by evacuating the ambient gas. In order to quantify the feedback effect on the gas density in the galactic centres, we utilise the outputs of IllustrisTNG and Illustris simulations, which implement different BH feedback models. We devise a physical model of H$_{\rm ~II}$ regions and compute the intensities of [O$_{\rm ~III}$] $52$ and $88~{\rm μm}$ lines. The line intensity ratio is sensitive to the local electron density, and thus can be used to measure the strength and physical extent of the BH quenching. If the BH feedback abruptly operates and expel the gas when it grows to a certain mass, as modelled in IllustrisTNG, the low-density gas yields relatively weak [O$_{\rm ~III}$] $52$ line with respect to $88~{\rm μm}$. In contrast, if the feedback strength and hence the local gas density are not strongly correlated with the BH mass, as in Illustris, the line ratio is not expected to vary significantly among galaxies with different evolutionary stages. We find these features are reproduced in the simulations. We also show that the line ratios are not sensitive to the aperture size for measurement, and thus observations do not need to resolve the galactic centres. We argue that the integrated line ratios can be used to capture the onset of the inside-out quenching by BHs.
The large Integral Field Spectroscopy (IFS) surveys have allowed the classification of ionizing sources of emission lines on sub-kpc scales. In this work, we define two non-parametric parameters, quiescence (f$_{q}$) and its concentration (c$_{q}$), to quantify the strength and the spatial distribution of the quenched areas, respectively, traced by the LI(N)ER regions with low EW(H$α$). With these two measurements, we classify MaNGA galaxies into inside-out and outside-in quenching types according to their locations on the f$_{q}$ vs. c$_{q}$ plane and we measure the fraction of inside-out (ou…
Using cosmological simulations, we address the interplay between structure and star formation in high-redshift galaxies via the evolution of surface density profiles. Our sample consists of 26 galaxies evolving in the redshift range $z=7-1$, spanning the stellar mass range $(0.2-6.4)\times 10^{10}M_\odot$ at $z=2$. We recover the main trends by stacking the profiles in accordance to their evolution phases. Following a wet compaction event that typically occurs when the stellar mass is $\sim10^{9.5}~M_{\odot}$ at $z\sim2-4$, the gas develops a cusp inside the effective radius, associated with a…
We constrain the spatial gradient of star formation history within galaxies using the colour gradients in NUV-u and u-i for a local spatially-resolved galaxy sample. By splitting each galaxy into an inner and an outer part, we find that most galaxies show negative gradients in these two colours. We first rule out dust extinction gradient and metallicity gradient as the dominant source for the colour gradient. Then using stellar population models, we explore variations in star formation history to explain the colour gradients. As shown by our earlier work, a two-phase SFH consisting of an early…
Inside-Out vs. Outside-In Quenching of MaNGA Galaxies: Dependence on Stellar Mass and Environment
National Tsing Hua University(国立清华大学);Institute of Astronomy & Astrophysics, Academia Sinica(中央研究院天文及天文物理研究所);Universidad Nacional Autónoma de México(墨西哥国立自治大学);National Taiwan Normal University(台湾师范大学);Hebei Normal University(河北师范大学);Shanghai Astronomical Observatory, Chinese Academy of Sciences(中国科学院上海天文台)
We present high spatial resolution imaging of the CO(1-0) line from the Karl G. Jansky Very Large Array (VLA) of COSMOS27289, a massive, compact star forming galaxy at z=2.234. This galaxy was selected to be structurally similar to z~2 passive galaxies. Our previous observations showed that it is very gas-poor with respect to typical star-forming galaxies at these redshifts, consistent with a rapid transition to quiescence as the molecular gas is depleted. The new data show that both the molecular gas fraction f_H2 = M_H2/M_star and the molecular gas depletion time t_dep = M_H2/SFR are lower i…
Most present-day galaxies with stellar masses $\geq10^{11}$ solar masses show no ongoing star formation and are dense spheroids. Ten billion years ago, similarly massive galaxies were typically forming stars at rates of hundreds solar masses per year. It is debated how star formation ceased, on which timescales, and how this "quenching" relates to the emergence of dense spheroids. We measured stellar mass and star-formation rate surface density distributions in star-forming galaxies at redshift 2.2 with $\sim1$ kiloparsec resolution. We find that, in the most massive galaxies, star formation i…
Observations of massive outflows with detectable central AGN typically find them within radii $\lesssim 10$ kpc. We show that this apparent size restriction is a natural result of AGN driving if this process injects total energy only of order the gas binding energy to the outflow, and the AGN varies over time (`flickers') as suggested in recent work. After the end of all AGN activity the outflow continues to expand to larger radii, powered by the thermal expansion of the remnant shocked AGN wind. We suggest that on average, outflows should be detected further from the nucleus in more massive g…
(Abridged) We explore the massive cluster XMMXCSJ2215.9-1738 at z~1.5 with KMOS spectroscopy of Halpha and [NII] covering a region that corresponds to about one virial radius. Using published spectroscopic redshifts of 108 galaxies in and around the cluster we computed the location of galaxies in the projected velocity vs. position phase-space to separate our cluster sample into a virialized region of objects accreted longer ago (roughly inside half R200) and a region of infalling galaxies. We measured oxygen abundances for ten cluster galaxies with detected [NII] lines in the individual galax…
We investigate a relation between surface densities of star formation rate (SFR) and stellar mass ($M_{*}$) at a $\sim 1$ kpc scale namely spatially resolved star formation main sequence (SFMS) in massive ($\log(M_{*}/M_{\odot})>10.5$) face-on disc galaxies at $0.01<z<0.02$ and $0.8<z<1.8$ and examine evolution of the relation. The spatially resolved SFMS of $z\sim 0$ galaxies is discussed in a companion paper. For $z\sim 1$ sample, we use 8 bands imaging dataset from CANDELS and 3D-HST and perform a pixel-to-pixel SED fitting to derive the spatially resolved SFR and $M_{*}$. We find a linear …
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…
Radial age gradients hold the cumulative record of the multitude of physical processes driving the build-up of stellar populations and the ensuing star formation (SF) quenching process in galaxy bulges, therefore potentially sensitive discriminators between competing theoretical concepts on bulge formation and evolution. Based on spectral modeling of integral field spectroscopy data from the CALIFA survey, we derive mass- and light-weighted stellar age gradients ($\nabla$(t,B)L,M) within the photometrically determined bulge radius (RB) of a representative sample of local face-on late-type gala…
We show that the bulge and the disk of the Milky Way (MW) at R$\lesssim$7~kpc are well described by a unique chemical evolution and a two-phase star-formation history (SFH). We argue that the populations within this inner disk, not the entire disk, are the same, and that the outer Lindblad resonance (OLR) of the bar plays a key role in explaining this uniformity. In our model of a two-phase star formation history, the metallicity, [$α$/Fe] and [$α$/H] distributions, and age-metallicity relation are all compatible with the observations of both the inner disk and bulge. The dip at [Fe/H]$\sim$0 …
We compare the star forming main sequence (SFMS) -- both integrated and resolved on 1kpc scales -- between the high-resolution TNG50 simulation of IllustrisTNG and observations from the 3D-HST slitless spectroscopic survey at z~1. Contrasting integrated star formation rates (SFRs), we find that the slope and normalization of the star-forming main sequence in TNG50 are quantitatively consistent with values derived by fitting observations from 3D-HST with the Prospector Bayesian inference framework. The previous offsets of 0.2-1dex between observed and simulated main sequence normalizations are …
We investigate how large-scale cosmic filaments impact the quenching of galaxies within one virial radius of 324 simulated clusters from The Three Hundred project. We track cosmic filaments with the versatile, observation-friendly program DisPerSE and identify halos hosting galaxies with VELOCIRaptor. We find that cluster galaxies close to filaments tend to be more star-forming, bluer, and contain more cold gas than their counterparts further away from filaments. This effect is recovered at all stellar masses. This is in stark contrast with galaxies residing outside of clusters, where galaxies…
Our knowledge about the photometric properties of bulges in late-type galaxies (LTGs) is founded upon image decomposition into a Sérsic model for the central luminosity excess of the bulge and an exponential model for the underlying disk. We argue that the standard practice of adopting an exponential model for the disk all the way to its center is inadequate because it implicitly neglects the fact of star formation (SF) quenching (SFQ) in the centers of LTGs. Extrapolating the fit for the observable star-forming zone of the disk (outside the bulge) inwardly overestimates the true surface brigh…
The THESAN-ZOOM project: central starbursts and inside-out quenching govern galaxy sizes in the early Universe
University of Cambridge(剑桥大学);The University of Texas at Dallas(德克萨斯大学达拉斯分校);York University(约克大学);Leibniz-Institut für Astrophysik Potsdam(波茨坦阿佩尔天体物理研究所);University of Pennsylvania(宾夕法尼亚大学);The University of Tokyo(东京大学);Institute for Fundamental Physics of the Universe(基础宇宙物理研究所);University of Edinburgh(爱丁堡大学)
We study the spatially resolved properties of 343 elliptical galaxies with the MaNGA/SDSS-IV survey. We used the DESI Legacy Imaging Surveys for morphological classification. Based on integrated spectroscopic properties and colors, we classified seven classes of ellipticals. We inferred the stellar age and metallicity ($Z$) gradients out to a 1.5 effective radius of classical "red and dead", recently quenched, and blue star-forming ellipticals (CLEs, RQEs, and BSFs), corresponding to 73%, 10%, and 4% of the sample, respectively. We reconstructed their global and radial histories of star format…
The timescales for galaxy quenching offer clues to its underlying physical drivers. We investigate central galaxy quenching timescales in the IllustrisTNG 100-1 simulation, their evolution over time, and the pre-quenching properties of galaxies that predict their quenching timescales. Defining quenching duration $τ_q$ as the time between crossing sSFR thresholds, we find that $\sim$40% of galaxies quench rapidly with $τ_q<$1 Gyr, but a substantial tail of galaxies can take up to 10 Gyr to quench. Furthermore, 29% of galaxies that left the star forming main sequence (SFMS) more than 2 Gyr ago n…
Clues to inside-out quenching in quiescent galaxies at $1.2\lesssim z\lesssim2.2$: Age, Fe-, and Mg-abundance gradients from JWST-SUSPENSE
Leiden University(莱顿大学);Observatories of the Carnegie Institution for Science(卡内基科学研究所天文台);University of the Pacific(太平洋大学);University of Pittsburgh(匹兹堡大学);Max-Planck-Institut für Astronomie(马克斯·普朗克天体物理学研究所);Max-Planck-Institut für extraterrestrische Physik(马克斯·普朗克地外物理学研究所);University of California, Berkeley(加州大学伯克利分校);Tufts University(塔夫茨大学);Instituto de Astrofísica de Canarias(加那利群岛天体物理研究所);Universidad de La Laguna(拉帕尔马大学);York University(约克大学)
Environment plays a critical role in the star formation history of galaxies. Tidal and hydrodynamical stripping, prominent in cluster environment, can remove the peripheral gas of galaxies and star formation may thus be environmentally suppressed from the outside-in. We revisit the environmental dependence of the radial gradient of specific star formation rate (sSFR) profile. We probe the radial gradient by using the archival spectral indices D4000n and HdA measured from SDSS fiber spectra, to indicate central sSFR, and the total sSFR from fitting the spectral energy distribution. Despite the …
The star formation history of galaxies is a complex process usually considered to be stochastic in nature, for which we can only give average descriptions such as the color-density relation. In this work we follow star-forming gas particles in a hydrodynamical N-body simulation back in time in order to study their initial spatial configuration. By keeping record of the time when a gas particle started forming stars we can produce gas-star isochrone surfaces delineating the surfaces of accreting gas that begin producing stars at different times. These accretion surfaces are closely packed insid…
(Abridged) We explore 7 clusters from LoCuSS at z~0.2 with spectra of 1965 cluster members from the ACReS Hectospec survey covering a region which corresponds to about three virial radii for each cluster. We measure fluxes of five emission lines of cluster members enabling us to unambiguously derive O/H gas metallicities, and also SFRs from extinction corrected Halpha fluxes. We compare our cluster galaxy sample with a field sample of 705 galaxies at similar redshifts observed with Hectospec. We find that star-forming cluster and field galaxies show similar median specific SFRs in a given mass…
We use cosmological simulations to study a characteristic evolution pattern of high redshift galaxies. Early, stream-fed, highly perturbed, gas-rich discs undergo phases of dissipative contraction into compact, star-forming systems (blue nuggets) at z~4-2. The peak of gas compaction marks the onset of central gas depletion and inside-out quenching into compact ellipticals (red nuggets) by z~2. These are sometimes surrounded by gas rings or grow extended dry stellar envelopes. The compaction occurs at a roughly constant specific star-formation rate (SFR), and the quenching occurs at a constant …
We study a sample of 48127 galaxies selected from the SDSS MPA-JHU catalogue, with $\log M_{\star}/M_{\odot} = 10.73 - 11.03$ and $z<0.1$. Local galaxies in this stellar mass range have been shown to have systematically shorter assembly times within their inner regions ($<0.5~R_{50}$) when compared to that of the galaxy as a whole, contrary to lower or higher mass galaxies which show consistent assembly times at all radii. Hence, we refer to these galaxies as Inside-Out Assembled Galaxy (IOAG) candidates. We find that the majority of IOAG candidates with well-detected emission lines are classi…
There are very strong observed correlations between the specific star-formation rates (sSFR) of galaxies and their mean surface mass densities, Σ, as well as other aspects of their internal structure. These strong correlations have often been taken to indicate that the internal structure of a galaxy must play a major physical role, directly or indirectly, in the control of star-formation. In this paper we show by means of a very simple toy model that these correlations can arise naturally without any such physical role once the observed evolution of the size-mass relation for star-forming gala…
We make use of a catalog of 1600 Pan-STARRS1 groups produced by the probability friends-of-friends algorithm to explore how the galaxy properties, i.e. the specific star formation rate (SSFR) and quiescent fraction, depend on stellar mass and group-centric radius. The work is the extension of Lin et al. (2014). In this work, powered by a stacking technique plus a background subtraction for contamination removal, a finer correction and more precise results are obtained than in our previous work. We find that while the quiescent fraction increases with decreasing group-centric radius the median …
Morphological and Star Formation Properties of Cosmic Noon Massive Quiescent Galaxies
Indian Institute of Science Education and Research Pune(印度科学教育研究所浦那分校);National Centre for Radio Astrophysics – Tata Institute of Fundamental Research(国家射电天体物理中心 - 塔塔基础研究院)
Dense environments have an impact on the star formation rate of galaxies. As stars form from molecular gas, looking at the cold molecular gas content of a galaxy gives useful insights on its efficiency in forming stars. However, most galaxies observed in CO (a proxy for the cold molecular gas content) at intermediate redshifts, are field galaxies. Only a handful of studies focused on cluster galaxies. I present new results on the environment of one medium mass cluster from the EDisCS survey at $z\sim0.5$. 27 star-forming galaxies were selected to evenly sample the range of densities encountere…
Interplay of Compaction, Quenching, and Black Hole Growth in the Most Massive Galaxies since $z\sim5$: Insights from JWST and Chandra Data
Tohoku University(东北大学);Indiana University(印第安纳大学);Stanford University(斯坦福大学);SLAC National Accelerator Laboratory(SLAC国家加速器实验室);Institut Teknologi Bandung(万隆理工学院);National Astronomical Observatory of Japan(日本国立天文台);Harvard-Smithsonian Center for Astrophysics(哈佛-史密森尼天体物理中心);Center for Astrophysics | Harvard & Smithsonian(天体物理中心 | 哈佛与史密森尼)
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. Su…
We study radial profiles in H$α$ equivalent width and specific star formation rate (sSFR) derived from spatially-resolved SDSS-IV MaNGA spectroscopy to gain insight on the physical mechanisms that suppress star formation and determine a galaxy's location in the SFR-$\rm M_\star$ diagram. Even within the star-forming `main sequence', the measured sSFR decreases with stellar mass, both in an integrated and spatially-resolved sense. Flat sSFR radial profiles are observed for $\rm log(M_\star/ M_\odot) < 10.5$, while star-forming galaxies of higher mass show a significant decrease in sSFR in the c…
We study the global and radial stellar mass assembly of eight zoomed-in MW-sized galaxies produced in Hydrodynamics cosmological simulations. The disk-dominated galaxies (4) show a fast initial stellar mass growth in the innermost parts, driven mostly by in-situ SF, but since $z\sim2-1$ the SF enters in a long-term quenching phase. The outer regions follow this trend but more gentle as more external they are. As the result, the radial stellar mass growth is highly inside-out due to both the inside-out structural growth and inside-out SF quenching. The half-mass radius evolves fast; for instanc…
Probing the molecular gas content of galaxies in an over-dense group at z~0.7: A test case for environmental quenching
Université de Strasbourg(斯特拉斯堡大学);Observatoire astronomique de Strasbourg(斯特拉斯堡天文台);Aix Marseille Univ(艾克斯-马赛大学);Canada-France-Hawaii Telescope(加拿大-法国-夏威夷望远镜);Université de Toulouse(图卢兹大学);Observatoire de Paris(巴黎天文台);PSL University(巴黎文理研究大学);Sorbonne University(索邦大学);Collège de France(法兰西公学院);Leibniz-Institut für Astrophysik Potsdam (AIP)(波茨坦莱布尼茨天体物理研究所)
In this Letter, we investigate how galaxy mass assembly mode depends on stellar mass $M_{\ast}$, using a large sample of $\sim$10, 000 low redshift galaxies. Our galaxy sample is selected to have SDSS $R_{90}>5\arcsec.0$, which allows the measures of both the integrated and the central NUV$-r$ color indices. We find that: in the $M_{\ast}-($ NUV$-r$) green valley, the $M_{\ast}<10^{10}~M_{\sun}$ galaxies mostly have positive or flat color gradients, while most of the $M_{\ast}>10^{10.5}~M_{\sun}$ galaxies have negative color gradients. When their central $D_{n}4000$ index values exceed 1.6, th…
Our aim is to understand the role of the environment in the quenching of star formation of galaxies located in the infall cluster region of Abell 85 (A85). This is achieved by studying the post-starburst galaxy population as tracer of recent quenching. By measuring the equivalent width (EW) of the [OII] and Hdelta spectral lines, we classify the galaxies in three groups: passive (PAS), emission line (EL), and post-starburst (PSB) galaxies. The PSB galaxy population represents about 4.5% of the full sample. Dwarf galaxies (Mr > -18.0) account for about 70 - 80% of PSBs, which indicates that mos…
The tight correlation between total galaxy stellar mass and star formation rate (SFR) has become known as the star forming main sequence. Using ~487,000 spaxels from galaxies observed as part of the Sloan Digital Sky Survey Mapping Galaxies at Apache Point Observatory (MaNGA) survey, we confirm previous results that a correlation also exists between the surface densities of star formation (Sigma_SFR) and stellar mass (Sigma_mass) on kpc scales, representing a `resolved' main sequence. Using a new metric (Delta Sigma_SFR), which measures the relative enhancement or deficit of star formation on …
Understanding the process of quenching is one of the major open questions in galaxy evolution, and crucial insights may be obtained by studying quenched galaxies at high redshifts, at epochs when the Universe and the galaxies were younger and simpler to model. However, establishing the degree of quiescence in high redshift galaxies is a challenging task. One notable example is Hyde, a recently discovered galaxy at z=3.709. As compact (r~0.5 kpc) and massive (M*~1e11 Msun) as its quenched neighbor Jekyll, it is also extremely obscured yet only moderately luminous in the sub-millimeter. Panchrom…
We derive two-dimensional dust attenuation maps at $\sim1~\mathrm{kpc}$ resolution from the UV continuum for ten galaxies on the $z\sim2$ Star-Forming Main Sequence (SFMS). Comparison with IR data shows that 9 out of 10 galaxies do not require further obscuration in addition to the UV-based correction, though our sample does not include the most heavily obscured, massive galaxies. The individual rest-frame $V$-band dust attenuation (A$_{\rm V}$) radial profiles scatter around an average profile that gently decreases from $\sim1.8$ mag in the center down to $\sim0.6$ mag at $\sim3-4$ half-mass …
We address the origin of the golden mass and time for galaxy formation and the onset of rapid black-hole growth. The preferred dark-halo mass of ~$10^{12}M_\odot$ is translated to a characteristic epoch, z~2, at which the typical forming halos have a comparable mass. We put together a coherent picture based on existing and new simple analytic modeling and cosmological simulations. We describe how the golden mass arises from two physical mechanisms that suppress gas supply and star formation below and above the golden mass, supernova feedback and virial shock heating of the circum-galactic medi…