Based on the colour measurements from a multi-band, multi-component 2D decomposition's of S0 and spiral galaxies using SDSS images, we found that bars are bluer in S0 galaxies compared to the spiral galaxies. Most of the S0s in our sample have stellar masses $\sim L_{*}$ galaxies. The environment might have played an important role as most of the S0s with bluer bars are in the intermediate-density environment. The possibility of minor mergers and tidal interactions which occurs frequently in the intermediate-density environment might have caused either a bar to form and/or induce star formation in the barred region of S0 galaxies. The underlying discs show the usual behaviour being redder in S0s compared to spiral galaxies while the bulges are red and old for both S0 and spiral galaxies. The finding of bluer bars in S0 galaxies is a puzzling issue and poses an interesting question at numerical and theoretical studies most of which shows that the bars are long-lived structures with old stellar populations.
We use reconstructed star-formation histories (SFHs) of quiescent galaxies at $z=0.6-1$ in the LEGA-C survey to identify secondary star-formation episodes that, after an initial period of quiescence, moved the galaxies back to the star-forming main sequence (blue cloud). $16\pm3$\% of the $z\sim0.8$ quiescent population has experienced such rejuvenation events in the redshift range $0.7<z<1.5$ after reaching quiescence at some earlier time. On average, these galaxies first became quiescent at $z=1.2$, and those that rejuvenated, remained quiescent for $\sim1$Gyr before their secondary SF episo…
Feedback, in particular from active galactic nuclei (AGN), is believed to play a crucial role in the evolution of galaxies. In the local Universe, many galaxies with an AGN are indeed observed to reside in the so-called green valley, usually interpreted as a transition phase from a blue star-forming to a red quenched state. We use data from the Sloan Digital Sky Survey to show that such an interpretation requires substantial revision. Optically-selected nearby AGN galaxies follow exponentially declining star formation histories, as normal galaxies of similar stellar and dark matter halo mass, …
Group Pre-processing in J1611+4026: Minor Rejuvenation of a Massive ETG fueled by Interaction-driven Gas Transfer
South-Western Institute for Astronomy Research, Yunnan University（西南天文研究所，云南大学）；School of Physics and Astronomy, Beijing Normal University（北京师范大学物理与天文学院）；Institute for Frontier in Astronomy and Astrophysics, Beijing Normal University（北京师范大学前沿天文与天体物理研究所）；Department of Physics, Nanchang University（南昌大学物理系）；Center for Relativistic Astrophysics and High Energy Physics, Nanchang University（南昌大学相对论天体物理与高能物理中心）；Purple Mountain Observatory, Chinese Academy of Sciences（中国科学院紫金山天文台）；Technical University of Munich, TUM School of Natural Sciences, Physics Department（慕尼黑工业大学自然科学学院物理系）；Max Planck Institute for Astrophysics（马克斯·普朗克天体物理学研究所）
Resolved Maps of Gas and Dust in a Massive Quiescent Galaxy at z=2 from INQUEST-JWST: Evidence of Accretion and Rejuvenation
Observatories of the Carnegie Institution for Science（卡内基科学研究所天文台）；Department of Astronomy, Tsinghua University（清华大学天文系）；Dipartimento di Fisica e Astronomia (DIFA), Università di Bologna（博洛尼塔大学物理与天文学系）；Department of Astronomy, University of Massachusetts, Amherst（马萨诸塞大学阿默斯特分校天文系）；Cosmic Dawn Center (DAWN)（宇宙黎明中心）；Centre for Astrophysics and Supercomputing, Swinburne University of Technology（斯威本科技大学天体物理与超级计算中心）
Evidence for the transformation from lenticular to spiral galaxies
University of Science and Technology of China（中国科学技术大学）；Beijing Normal University（北京师范大学）；Nanjing University（南京大学）；University of California, Riverside（加州大学河滨分校）；University of Massachusetts, Amherst（马萨诸塞大学阿默斯特分校）
We study the spatially resolved star formation history and molecular gas distribution of 58 nearby galaxies, using integral field spectroscopy from the CALIFA survey and CO $J=1\rightarrow 0$ intensity mapping from the CARMA EDGE survey. We use the 4000 Å break (D$_n$4000), the equivalent width of the H$δ$ absorption line (EW H$δ_A$), and the equivalent width of the H$α$ emission line (EW H$α$) to measure the recent star formation history (SFH) of these galaxies. We measure radial profiles of the three SFH indicators and molecular gas mass surface density, from which we measure the level of ce…
Stellar bars have been found to substantially influence the stellar populations properties in galaxies, affecting their ability of forming stars. While this can be easily seen when studying galaxies in relatively isolated environments, such kind of analysis takes a higher degree of complexity when cluster galaxies are considered, due to the variety of interactions which can potentially occur in these denser environments. We use IFU MUSE data from the GASP survey to study the combined effect of the presence of a stellar bar and of ram pressure, on spatially resolved properties of stellar popula…
We investigate the recent star formation history (SFH) in the inner region of 57 nearly face-on spiral galaxies selected from the Calar Alto Legacy Integral Field Area (CALIFA) survey. For each galaxy we use the integral field spectroscopy from CALIFA to obtain two-dimensional maps and radial profiles of three parameters that are sensitive indicators of the recent SFH: the 4000Å break (D$_n$(4000)), and the equivalent width of H$δ$ absorption (EW(H$δ_A$)) and H$α$ emission (EW(H$α$)). We have also performed photometric decomposition of bulge/bar/disk components based on SDSS optical image. We …
Where Giants Dwell: Probing the Environments of Early Massive Quiescent Galaxies
INAF - Astronomical Observatory of Trieste（意大利国家天体物理研究所的里雅斯特天文台）；IFPU - Institute for Fundamental Physics of the Universe（宇宙基础物理研究所）；Tianjin Normal University（天津师范大学）；Institute for Physics, Laboratory for Galaxy Evolution, EPFL（洛桑联邦理工学院星系演化实验室）
Galaxies broadly fall into two categories: star-forming (blue) galaxies and quiescent (red) galaxies. In between, one finds the less populated ``green valley". Some of these galaxies are suspected to be in the process of ceasing their star-formation through a gradual exhaustion of gas supply or already dead and are experiencing a rejuvenation of star-formation through fuel injection. We use the Galaxy And Mass Assembly database and the Galaxy Zoo citizen science morphological estimates to compare the morphology of galaxies in the green valley against those in the red sequence and blue cloud. O…
We study the star formation activity of nearby galaxies with bars using a sample of late-type galaxies at 0.02$\leq z \leq$ 0.05489 and $M_r <-19.5$ from the Sloan Digital Sky Survey. We compare the physical properties of strongly and weakly barred galaxies with those of non-barred galaxies that have stellar mass and redshift distributions similar to barred galaxies. We find that the star formation activity of strongly barred galaxies probed by starburstiness, $\it{g-r}$, NUV$-r$, and mid-infrared [3.4]$-$[12] colors is, on average, lower than that of non-barred galaxies. However, weakly barre…
We present a detailed study of the molecular gas content and stellar population properties of three massive galaxies at 1 < z < 1.3 that are in different stages of quenching. The galaxies were selected to have a quiescent optical/near-infrared spectral energy distribution and a relatively bright emission at 24 micron, and show remarkably diverse properties. CO emission from each of the three galaxies is detected in deep NOEMA observations, allowing us to derive molecular gas fractions Mgas/Mstar of 13-23%. We also reconstruct the star formation histories by fitting models to the observed photo…
We present evidence of bar-induced secular evolution in galactic discs using 3.6 ${μm}$ images of nearby galaxies from the Spitzer Survey of Stellar Structure in Galaxies (S4G). We find that among massive galaxies ($M_{star}/M_{sun}> 10^{10}$), longer bars tend to reside in inner discs having a flatter radial profile. Such galaxies show a light deficit in the disc surrounding the bar, within the bar radius and often show a $Θ$-shaped morphology. We quantify this deficit and find that among all galaxies explored in this study (with $10^{9}<M_{star}/M_{sun}< 10^{11}$), galaxies with a stronger b…
(Abridge) Bars are very common in the centre of the disc galaxies, and they drive the evolution of their structure. A volume-limited sample of 2106 disc galaxies extracted from the Sloan Digital Sky Survey Data Release 5 was studied to derive the bar fraction, length, and strength as a function of the morphology, size, local galaxy density, light concentration, and colour of the host galaxy. The bars were detected using the ellipse fitting method and Fourier analysis method. The ellipse fitting method was found to be more efficient in detecting bars in spiral galaxies. The fraction of barred g…
We explore properties of barred active spiral galaxies in groups selected from the SDSS-DR7, with the aim of assessing the effects of bars on AGN and the role of the high density environment. We identified barred active galaxies that reside in groups from SDSS-DR7 group catalog. To provide a suitable quantification of the effects of bars, a reliable control sample of unbarred active galaxies in high density environments with similar redshift, magnitude, morphology, and bulge size distributions was constructed. We found that the fraction of barred AGN galaxies in groups (~ 38 %) is higher than …
We present the initial results of a census of 684 barred galaxies in the MaNGA galaxy survey. This large sample contains galaxies with a wide range of physical properties, and we attempt to link bar properties to key observables for the whole galaxy. We find the length of the bar, when normalised for galaxy size, is correlated with the distance of the galaxy from the star formation main sequence, with more passive galaxies hosting larger-scale bars. Ionised gas is observed along the bars of low-mass galaxies only, and these galaxies are generally star-forming and host short bars. Higher-mass g…
Stellar bars are important internal drivers of secular evolution in disk galaxies. Using a sample of nearby spiral galaxies with weak and strong bars, we explore the relationships between the star formation feature and stellar bars in galaxies. We find that galaxies with weak bars tend to be coincide with low concentrical star formation activity, while those with strong bars show a large scatter in the distribution of star formation activity. We find enhanced star formation activity in bulges towards stronger bars, although not predominantly, consistent with previous studies. Our results sugge…
We have used Galaxy Zoo DECaLS (GZD) to study strong and weak bars in disk galaxies. Out of the 314,000 galaxies in GZD, we created a volume-limited sample (0.01 < z < 0.05, Mr < -18.96) which contains 1,867 galaxies with reliable volunteer bar classifications in the ALFALFA footprint. In keeping with previous Galaxy Zoo surveys (such as GZ2), the morphological classifications from GZD agree well with previous morphological surveys. GZD considers galaxies to either have a strong bar (15.5%), a weak bar (28.1%) or no bar (56.4%), based on volunteer classifications on images obtained from the DE…
We performed a series of 29 gasdynamical simulations of disc galaxies, barred and unbarred, with various stellar masses, to study the impact of the bar on star formation history. Unbarred galaxies evolve very smoothly, with a star formation rate (SFR) that varies by at most a factor of three over a period of 2 Gyr. The evolution of barred galaxies is much more irregular, especially at high stellar masses. In these galaxies, the bar drives a substantial amount of gas toward the centre, resulting in a high SFR, and producing a starburst in the most massive galaxies. Most of the gas is converted …
We study the bar pattern speeds and corotation radii of 225 barred galaxies, using IFU data from MaNGA and the Tremaine-Weinberg method. Our sample, which is divided between strongly and weakly barred galaxies identified via Galaxy Zoo, is the largest that this method has been applied to. We find lower pattern speeds for strongly barred galaxies than for weakly barred galaxies. As simulations show that the pattern speed decreases as the bar exchanges angular momentum with its host, these results suggest that strong bars are more evolved than weak bars. Interestingly, the corotation radius is n…
We analyze the correlation between properties of large-scale bars and atomic gas content of galaxies to explore the role of HI gas on bar evolution in galaxies. We show that the absolute bar size depends strongly on total stellar mass of galaxies and does not change significantly with HI gas fraction at fixed stellar mass. Furthermore, the physical size of the bar is small and nearly constant in high Hi gas fraction and low-mass galaxies, and becomes larger with increasing galactic stellar mass in low gas fraction galaxies. When the stellar masses are fixed, the relative bar length normalized …
We investigate the relations between the properties of bars and their host galaxies in a sample of 77 nearby barred galaxies, spanning a wide range of morphological types and luminosities, with 34 SB0-SBa and 43 SBab-SBc galaxies. The sample includes all the galaxies with reliable direct measurement of their bar pattern speed based on long-slit or integral-field stellar spectroscopy using the Tremaine-Weinberg method. We limited our analysis to the galaxies with a relatively small relative error on the bar pattern speed (smaller than 50 per cent) and not hosting an ultrafast bar. For each gala…
We present a study of the environment of barred galaxies using a volume-limited sample of over 30,000 galaxies drawn from the Sloan Digital Sky Survey. We use four different statistics to quantify the environment: the projected two-point cross-correlation function, the background-subtracted number count of neighbor galaxies, the overdensity of the local environment, and the membership of our galaxies to galaxy groups to segregate central and satellite systems. For barred galaxies as a whole, we find a very weak difference in all the quantities compared to unbarred galaxies of the control sampl…
Galactic bars can affect the evolution of galaxies by redistributing gas in galaxies, possibly contributing to the cessation of star formation. Recent works point to 'bar quenching' playing an important role in massive disk galaxies like the Milky Way. We construct the largest ever sample of gas rich and strongly barred disc galaxies with resolved HI observations making use of both the Giant Meter Radio Telescope (GMRT) and the Karl Jansky Very Large Array (VLA) to collect data. This sample, called HIRB (HI Rich Barred) galaxies, were identified with Galaxy Zoo - to find galaxies hosting a str…
Bars in disc-dominated galaxies are able to drive gas inflow inside the corotation radius, thus enhancing the central star formation rate (SFR). Previous work, however, has found that disc-dominated galaxies with centrally suppressed SFR frequently host a bar. Here we investigate possible causes for the suppression of central SFR in such cases. We compare physical properties of a sample of disc-dominated barred galaxies with high central SFR (HC galaxies) with those of a sample of disc-dominated barred galaxies with low central SFR (LC galaxies). We find that the two samples have on average si…
We aim at investigating the formation process of weak bars by measuring their properties in a sample of 29 nearby SAB galaxies, spanning a wide range of morphological types and luminosities. The sample galaxies were selected to have an intermediate inclination, a bar at an intermediate angle between the disc minor and major axes, and an undisturbed morphology and kinematics to allow the direct measurement of the bar pattern speed. Combining our analysis with previous studies, we compared the properties of weak and strong bars. We measured the bar radius and strength from the r-band images avai…
We present a study of the environment of barred galaxies using galaxies drawn from the SDSS. We use several different statistics to quantify the environment: the projected two-point cross-correlation function, the background-subtracted number count of neighbor galaxies, the overdensity of the local environment, the membership of our galaxies to galaxy groups to segregate central and satellite systems, and for central galaxies we estimate the stellar to halo mass ratio (M$_{\mathrm{*}}/$M$_{\mathrm{h}}$) . When we split our sample into early- and late-type galaxies, we see a weak but significan…
Almost two-thirds of disk galaxies in the local universe host bars, which serve as important drivers of secular evolutionary processes. While cosmological simulations are powerful tools to study the formation and evolution of galaxies, they have often struggled to generate reasonable bar populations. We measure the fraction, size, and strength of bars in 3866 disk galaxies from the TNG100 run of the advanced cosmological simulation IllustrisTNG. Consistent with observations, about 55% of disk galaxies with stellar mass $M_* \approx 10^{10.6}\, M_\odot$ are barred, and the relation between bar …
We use the magnetic-hydrodynamical simulation TNG50 to study the evolution of barred massive disc galaxies. Massive spiral galaxies are already present as early as $z=4$, and bar formation takes place already at those early times. The bars grow longer and stronger as the host galaxies evolve, with the bar sizes increasing at a pace similar to that of the disc scale lengths. The bar fraction mildly evolves with redshift for galaxies with $M_{*}\geq10^{10}M\odot$, being greater than $\sim40\%$ at $0.5<z<3$ and $\sim30\%$ at $z=0$. When bars larger than a given physical size ($\geq 2\,\rm kpc$) o…
The suppression of star formation in the inner kiloparsec regions of barred disk galaxies due to the action of bars is known as bar quenching. We investigate here the significance of bar quenching in the global quenching of star formation in the barred galaxies and their transformation to passive galaxies in the local Universe. We do this by measuring the offset of quenched barred galaxies from star-forming main sequence galaxies in the star formation rate-stellar mass plane and comparing it with the length of the bar, which is considered as a proxy of bar quenching. We constructed the star fo…
Bars are common in low-redshift disk galaxies, and hence quantifying their influence on their host is of importance to the field of galaxy evolution. We determine the stellar populations and star formation histories of 245 barred galaxies from the MaNGA galaxy survey, and compare them to a mass- and morphology-matched comparison sample of unbarred galaxies. At fixed stellar mass and morphology, barred galaxies are optically redder than their unbarred counterparts. From stellar population analysis using the full spectral fitting code Starlight, we attribute this difference to both older and mor…
We present a near-infrared (NIR) imaging study of barred low surface brightness (LSB) galaxies using the TIFR near-infrared Spectrometer and Imager (TIRSPEC). LSB galaxies are dark matter dominated, late type spirals that have low luminosity stellar disks but large neutral hydrogen (HI) gas disks. Using SDSS images of a very large sample of LSB galaxies derived from the literature, we found that the barred fraction is only 8.3%. We imaged twenty five barred LSB galaxies in the J, H, K$_S$ wavebands and twenty nine in the K$_S$ band. Most of the bars are much brighter than their stellar disks, …
Aims: With the aim of assessing the effects of bars on disc galaxy properties, we present an analysis of different characteristics of spiral galaxies with strong, weak and without bars. Method: We identified barred galaxies from the Sloan Digital Sky Survey. By visual inspection, we classified the face-on spiral galaxies brighter than g<16.5 mag into strong-bar, weak-bar and unbarred. In order to provide an appropiate quantification of the influence of bars on galaxy properties, we also constructed a suitable control sample of unbarred galaxies with similar redshift, magnitude, morphology, bul…
We present a study of barred galaxies in the cluster environment, exploiting a sample of galaxies drawn from the extended WIde-field Nearby Galaxy-cluster Survey (OmegaWINGS) that covers up to the outer regions of 32 local X-ray selected clusters. Barred galaxies are identified through a semi-automatic analysis of ellipticity and position angle profiles. We find, in agreement with previous studies, a strong co-dependence of the bar fraction with the galaxy stellar mass and morphological type, being maximum for massive late-type galaxies. The fraction of barred galaxies decreases with increasin…
We present the results of two-component (disc+bar) and three-component (disc+bar+bulge) multiwavelength 2D photometric decompositions of barred galaxies in five SDSS bands ($ugriz$). This sample of $\sim$3,500 nearby ($z<0.06$) galaxies with strong bars selected from the Galaxy Zoo citizen science project is the largest sample of barred galaxies to be studied using photometric decompositions which include a bar component. With detailed structural analysis we obtain physical quantities such as the bar- and bulge-to-total luminosity ratios, effective radii, Sérsic indices and colours of the indi…
Bar-induced gas inflows towards the galaxy centres are recognized as a key agent for the secular evolution of galaxies. One immediate consequence is the accumulation of gas in the centre of galaxies where it can form stars and alter the chemical and physical properties. We use a sample of nearby face--on disc galaxies with available SDSS spectra to study whether the properties of the ionised gas in the central parts (radii <~0.6-2.1 kpc) of barred galaxies are altered by the presence of a bar, and whether the bar effect is related to bar and/or parent galaxy properties. The distributions of al…
This work is dedicated to investigation of galaxies that do not fit into a common scenario of galaxy formation - isolated lenticular galaxies. We have studied stellar populations and ionized gas content of a sample of 22 lenticular galaxies (among those 4 targets have appeared to be of erroneous morphological classification) by undertaking deep long-slit spectroscopy with the Russian 6-m telescope and with the Southern African Large Telescope (SALT). The obtained average ages of the stellar populations in bulges and discs covers a wide range between 1.5 and >15 Gyr, that indicates the absence …
With the aim of assessing if low surface brightness galaxies host stellar bars, and study the dependence of the occurrence of bars as a function of surface brightness, we use the Galaxy Zoo 2 dataset to construct a large volume-limited sample of galaxies, and segregate the galaxies as low and high surface brightness in terms of their central surface brightness. We find that the fraction of low surface brightness galaxies hosting strong bars is systematically lower than the one found for high surface brightness galaxies. The dependence of the bar fraction on the central surface brightness is mo…
We carried out $^{12}$CO(J = 1 -0) observations toward bar and arm regions of strongly barred galaxies, NGC 1300 and NGC 5383, with the Nobeyama 45-m radio telescope (beamsize of 1-2 kpc in the galaxies). The aim of the observations is to qualitatively examine a new scenario for the suppression of star formation in bars based on recent high-resolution numerical simulations: higher speed collisions between molecular clouds in the bar region compared with the arm region suppress the massive star formation. CO emissions were detected from all the regions, indicating the presence of the molecular …
We select a sample of galaxies from the Sloan Digital Sky Survey Data Release 7 (SDSS-DR7) where galaxies are classified, through visual inspection, as hosting strong bars, weak bars or as unbarred galaxies, and make use of HI mass and kinematic information from the Arecibo Legacy Fast ALFA (ALFALFA) survey catalog, to study the stellar, atomic gas and dark matter content of barred disk galaxies. We find, in agreement with previous studies, that the bar fraction increases with increasing stellar mass. A similar trend is found with total baryonic mass, although the dependence is not as strong a…
Bars in galaxies are thought to stimulate both inflow of material and radial mixing along them. Observational evidence for this mixing has been inconclusive so far however, limiting the evaluation of the impact of bars on galaxy evolution. We now use results from the MaNGA integral field spectroscopic survey to characterise radial stellar age and metallicity gradients along the bar and outside the bar in 128 strongly barred galaxies. We find that age and metallicity gradients are flatter in the barred regions of almost all barred galaxies when compared to corresponding disk regions at the same…
Athanassoula (2014) has claimed that measurements of the ratio of corotation radius to bar length in galaxies do not place a constraint on the disk to halo mass ratio. Her conclusion was based on a series of simulations published by Athanassoula et al. (2013). Here we show that these results are, in fact, consistent with previous work on the slow down of bars due to dynamical friction because gas inflow rearranges the disk mass before the bar settles. It therefore remains true that a bar rotating sufficiently fast that corotation is not far beyond the bar end requires a near maximum disk.
Bars inhabit the majority of local-Universe disk galaxies and may be important drivers of galaxy evolution through the redistribution of gas and angular momentum within disks. We investigate the star formation and gas properties of bars in galaxies spanning a wide range of masses, environments, and star formation rates using the MaNGA galaxy survey. Using a robustly-defined sample of 684 barred galaxies, we find that fractional (or scaled) bar length correlates with the host's offset from the star-formation main sequence. Considering the morphology of the H$α$ emission we separate barred galax…
A fraction of early-type dwarf galaxies in the Virgo cluster have a disk component and even possess disk features such as bar, lens, and spiral arms. In this study, we construct 15 galaxy models that resemble VCC856, considered to be an infalling progenitor of disk dwarf galaxies, within observational error ranges, and use $N$-body simulations to study their long-term dynamical evolution in isolation as well as the formation of bar in them. We find that dwarf disk galaxies readily form bars unless they have an excessively concentrated halo or a hot disk. This suggests that infalling dwarf disk…
We use 3.6 $μ$m photometry from the Spitzer Survey of Stellar Structure in Galaxies (S$^{4}$G) to trace the stellar distribution in nearby disk galaxies ($z\approx0$) with total stellar masses $10^{8.5}\lesssim M_{\ast}/M_{\odot}\lesssim10^{11}$ and mid-IR Hubble types $-3 \le T \le 10$, and to provide observational constraints for galaxy formation models to be checked against. For 1154 galaxies with disk inclinations lower than $65^{\circ}$, we Fourier decompose and rescale their images to a common frame determined (i) by the size in physical units, (ii) by their disk scalelength, and for 748…
Earlier studies have shown that massive bulges impede bar formation in disk galaxies. Recent N-body simulations have derived a bar formation criterion that depends on the radial bulge force in a galaxy disk. We use those simulations to show that bars can form only when the force constant FB < 0.13, where FB depends on the ratio of the bulge force to the total force of the galaxy at twice the disk scale length 2R d . In this article, we test this theoretical prediction using observational data obtained from the literature. Our sample consists of 63 barred galaxies with a wide range of Hubble cl…
