Feedback from supernovae (SNe) is an essential mechanism that self-regulates the growth of galaxies. We build an SN feedback model based on high-resolution simulations of superbubble and SN-driven outflows for the physical understanding of the galaxy–CGM connection. Using an Eulerian hydrodynamic code Athena++, we find universal scaling relations for the time evolution of superbubble momentum, when the momentum and time are scaled by those at the shell-formation time. We then develop an SN feedback model utilizing Voronoi tessellation, and implement it into the GADGET3-Osaka smoothed particle hydrodynamic code. We show that our stochastic thermal feedback model produces galactic outflow that carries the metals high above the galactic plane but with weak suppression of star formation. Additional mechanical feedback further suppresses star formation. Therefore, we argue that both thermal and mechanical feedback is necessary for the SN feedback model of galaxy evolution when an individual SN bubble is unresolved.

To study the role of H i content in galaxy interactions, we select galaxy pairs and control galaxies from the SDSS-IV MaNGA IFU survey, adopting kinematic asymmetry as a new effective indicator to describe the merger stage. With archival data from the HI-MaNGA survey and new observations from the Five-hundred-meter Aperture Spherical radio Telescope (FAST), we investigate the differences in H i gas fraction (fH i), star formation rate (SFR), and H i star formation efficiency (SFEH i) between pairs and controls. Our results suggest that on average the H i gas fraction of major-merger pairs is marginally decreased by ∼ 15% relative to isolated galaxies, and paired galaxies during pericentric passage show weakly decreased fH i (−0.10 ± 0.05 dex), significantly enhanced SFR (0.42 ± 0.11 dex), and SFEH i (0.48 ± 0.12 dex). We propose the marginally detected H i depletion may originate from the gas consumption in fueling the enhanced H2 reservoir of galaxy pairs.

Even though galactic winds are common in galaxies with starbursts or active galactic nuclei (AGN), the role of such gas flows in galaxy evolution remains uncertain. Here we examine how winds vary along a likely evolutionary sequence connecting starburst to post-starburst to quiescent galaxies. To detect the interstellar medium and measure its bulk flows, we examine the residual Na D absorption line doublet after the stellar contribution has been removed from each galaxy’s spectrum. We discover that outflows diminish along this sequence, i.e., as star formation ends. We then focus on the wind behavior within the post-starburst sample, for which we have measured the time elapsed since the starburst ended (post-burst age) via detailed modeling of their star formation histories (French et al.2018). Even within our post-starburst sample, the fraction of galaxies with significant winds and the average wind velocities decrease with post-burst age after controlling for stellar mass.

HI and CO observations indicate that the cold gas in galaxies is very turbulent. However, the turbulent energy is expected to be quickly dissipated, implying that some energy source is needed to explain the observations. The nature of such turbulence was long unclear, as even the main candidate, supernova (SN) feedback, seemed insufficient. Other mechanisms have been proposed, but without reaching a general consensus. The key novelty of our work is considering that the gas disc thickness and flaring increase the dissipation timescale of turbulence, thus reducing the energy injection rate required to sustain it. In excellent agreement with the theoretical expectations, we found that the fraction of the SN energy (a.k.a. SN coupling efficiency) needed to maintain the cold gas turbulence is ∼ 1%, solving a long-standing conundrum.

In the title of this Symposium: “The rise and fall of star formation in galaxies”, the “falling” stage is mostly represented by so-called Green Valley galaxies. In this phase, quenching mechanisms operate, concerning the evolution from star formation towards quiescence. Therefore, GV galaxies are ideal laboratories to test cosmological simulations. This contribution focuses on the application of a novel, dust-independent, definition of the GV, to two of the most recent simulations: EAGLE and Illustris-TNG. We present some of the results, concerning the excess fraction of quenched galaxies in simulations, with respect to observational data from SDSS. We suggest possible causes for the mismatch.

Whether the star formation efficiency (SFE) in the bar region is lower than those in the other regions in a barred galaxy has recently been debated. We statistically investigate the SFEs along the bars in nearby gas-rich massive star-forming barred galaxies by distinguishing the center, bar-end, and bar regions for the first time. The molecular gas surface density is derived from archival CO(1–0) and/or CO(2–1) data and the star formation rate surface density is derived from a linear combination of far-ultraviolet and mid-infrared intensities. To distinguish the three regions, we targeted 18 galaxies with a large apparent bar length (≥ 75"). The resulting SFE in the bars is about 0.6 – 0.8 times lower than that in the disks, which suggests the star formation in the bars tends to be systematically suppressed.

We have studied the star formation properties of a massive void galaxy - I Zw 81. We performed 2D structural decomposition on Canada France Hawaii Telescope (CFHT) g- and r-band observation of I Zw 81 using GALFIT. The galaxy consists of an unresolved small bulge, a bar, an inner ring, and a truncated disk. We have used far-ultraviolet (FUV) and near-UV (NUV) observation of Ultraviolet Imaging Telescope (UVIT) onboard AstroSat for our analysis. The NUV–r color map of the lenticular galaxy illustrates a shallow positive color gradient in the profile, implying that the bar and inner ring are more star-forming than the outer disk. The FUV emission is mainly concentrated in the central region of the galaxy. A tidal tail-like feature is detected in the CFHT observations. We infer that bar and minor mergers-like interactions enhance the gas inflow and drive star formation in the center of I Zw 81.

The Atacama Large Millimetre/Sub-millimetre Array (ALMA) is obtaining the deepest observations of early galaxies ever achieved at (sub-)millimetre wavelengths, and detecting the dust emission of young galaxies in the first billion years of cosmic history, well in the epoch of reionization. Here I review some of the latest results from these observations, with special focus on the REBELS large programme, which targets a sample of 40 star-forming galaxies at z ⋍ 7. ALMA detects significant amounts of dust in very young galaxies, and this dust might have different properties to dust in lower-redshift galaxies. I describe the evidence for this, and discuss theoretical/modelling efforts to explain the dust properties of these young galaxies. Finally, I describe two additional surprising results to come out of the REBELS survey: (i) a new population of completely dust-obscured galaxies at z ⋍ 7, and (ii) the prevalence of spatial offsets between the ultraviolet and infrared emission of UV-bright, high-redshift star-forming galaxies.

Remarkable progress has been made in the last few years in understanding the global properties of galaxies and how they evolve through cosmic time. Major focus has been given to studies of how the availability of molecular gas regulates star-forming activity and galaxy growth, the eventual quenching of star formation, and how these mechanisms evolve through cosmic time. Most of these advances have been made thanks to ALMA and the upgraded capabilities of NOEMA. In this contribution, I briey review the latest constraints on the molecular gas content based on dierent tracers of the interstellar medium (ISM; dust continuum and CO, [CI] and [CII] line emission), including recent determinations of the molecular gas fraction, gas depletion timescales, and molecular gas cosmic density provided by the recent ALMA programs out to z ∼ 7. Finally, I concentrate on recent and ongoing studies aiming to spatially and kinematically resolve the cold ISM and star formation activity down to kpc scales in galaxies out to z ∼ 6 – 7, which represent an unprecedented view of the galaxy assembly and feedback processes in the early universe.

The TYPHOON program is producing an atlas of spectroscopic data cubes of 44 large-angular-sized galaxies with complete spatial coverage from 3650–9000 Å. This survey provides an unparalleled opportunity to study variations in the interstellar medium (ISM) properties within individual H ii regions across the entire star-forming disks of nearby galaxies. This can provide key insights into the spatial distribution and resolved properties of the ISM to understand how efficiently metals are mixed and redistributed across spirals and dwarf galaxies. In this Proceeding, we present early science results from six nearby spiral galaxies as part of the TYPHOON program from Grasha et al. (2022). We use HIIPhot to identify the H ii regions within the galaxy based on the surface brightness of the Hα emisison line and measure variations of the H ii region oxygen abundance. In this initial work, we find that while the spiral pattern plays a role in organizing the ISM, it alone does not establish the relatively uniform azimuthal variations we observe across all the galaxies. Differences in the metal abundances are more likely driven by the strong correlations with the local physical conditions. We find a strong and positive correlation between the ionization parameter and the local abundances as measured by the relative metallicity offset Δ(O/H), indicating a tight relationship between local physical conditions and their localized enrichment of the ISM. These variations can be explained by a combination of localized, star formation-driven self-enrichment and large-scale mixing-driven dilution due to the passing of spiral density waves.

Local Group (LG), the nearest and most complete galactic environment, provides valuable information on the formation and evolution of the Universe. Studying galaxies of different sizes, morphologies, and ages can provide this information. For this purpose, we chose the And IX dSph galaxy, which is one of the observational targets of the Isaac Newton Telescope (INT) survey. A total of 50 long-period variables (LPVs) were found in And IX in two filters, Sloan i' and Harris V at a half-light radius of 2.5 arcmin. The And IX’s star formation history (SFH) was constructed with a maximum star formation rate (SFR) of about 0.00082 ± 0.00031 M⊙ yr−1, using LPVs as a tracer. The total mass return rate of LPVs was calculated based on the spectral energy distribution (SED) of about 2.4 × 10−4 M⊙ yr−1. The distance modulus of 24.56−0.15+0.05 mag was estimated based on the tip of the red giant branch (TRGB).

Pristine gas accretion is expected to be the main driver of sustained star formation in galaxies. We measure the required amount of accreted gas at each moment over a galaxy’s history to produce the observed metallicity at that time given its star-forming history. More massive galaxies tend to have higher accretion rates and a larger drop of the accretion rate towards the present time. Within the same mass bin galaxies that are currently star-forming or in the Green Valley have similar, sustained, accretion histories while retired galaxies had a steep decline in the past. Plotting the T80 of the individual accretion histories, a measure of how sustained they are, versus the stellar mass and current sSFR we see a distribution such that currently star-forming galaxies have sustained or recent accretion and retired galaxies have declined accretion histories.

Detection of transients such as supernovae (SNe) and kilonovae (KNe) in early phase has recently become important for understanding the progenitor properties and multi-messenger astronomy. Predicting which galaxy has the higher probability of hosting the transient events would help detect the early phase of the events and get information on their progenitors. The SN and KN rates are known to be a function of star formation rate (SFR) and stellar mass of the host galaxy. The SFR of a galaxy can be estimated from ultraviolet (UV) luminosity. However, the UV magnitudes have been derived carefully only for a limited number of nearby galaxies. Here, we introduce GALEX galaxy catalog of all-sky UV brightness of low redshift galaxies. To do so, we derive the UV photometry of galaxies in the GLADE catalog using the GALEX AIS images, supplemented by GALEX NGS and MIS data. From the near-UV (NUV) and far-UV (FUV) magnitudes, we calculate the SFRs of the galaxies, which will further be useful for estimating the SN and KN rate. The results are compared with previous GALEX UV catalog of galaxies. There will be an updated catalog based on this catalog for calculating KN rate of the galaxies in the future work.

The interplay between star formation (SF) activity and active galactic nuclei (AGN) governs the co-evolution of supermassive black holes (SMBHs) and their host galaxies. AGN feedback has been hailed as the de facto process to suppress, or even shut down SF within the framework of hierarchical galaxy merger based on the current ΛCDM paradigm. However, it is unclear what physical processes regulate the growth of SMBHs and how SMBHs and their evolution are interconnected with their host galaxies when SMBHs and host galaxies are of hugely different physical scales. In fact, there has been no observational evidence to show that AGN feedback works, but rather some evidence to speculate that the more powerful AGNs reside in the more actively star-forming host galaxies. While it is difficult to measure the amount of SF from AGN host galaxies, polycyclic aromatic hydrocarbon (PAH) emission features emerged as good proxies for this purpose. Although having several caveats as SFR indicators, such as metallicity dependency, and non-SF contribution from evolved stellar populations, or AGNs, PAH emissions have been utilized to investigate SF activity of AGN host galaxies with varying results. Utilizing the slitless spectroscopic apability of the AKARI Infrared Camera, we obtained the spectra in the wavelength range of 2∼5 μm from extended regions of 79 type 1 AGN host galaxies to detect and measure the 3.3 μm (PAH) emission feature as star formation rate proxy. Based on 18 sample galaxies, we found that the luminosity of the 3.3 μm PAH emission feature is strongly correlated with AGN luminosity, except for ultra-luminous infrared galaxies (ULIRGs). Therefore, we suggest that host galaxies with stronger AGN activities have stronger star formation activities. However, it is still unclear why ULIRGs deviate from the correlation, not to mention why the detection rate of the 3.3 μm emission feature is so low. High spatial resolution imaging not only for the circumnuclear region of AGN host galaxies, but also for entire galaxies should help the cause. We present the prospective studies to diagnose SF regulation for AGN host galaxies with various space telescope facilities, such as JWST, and SPHEREx.

We use archival WISE and Spitzer photometry to derive optical emission line fluxes for a sample of distant quasars at z∼6. We find evidence for exceptionally high equivalent width [OIII] emission (rest-frame EW∼400Å) similar to that inferred for star-forming galaxies at similar redshifts. The median Hα and Hβ equivalent widths are derived to be ∼400Å and ∼100Å respectively, and are consistent with values seen among quasars in the local Universe, and at z ∼ 2. After accounting for the contribution of photoionization in the broad line regions of quasars, we suggest that the narrow [OIII] emission likely arises from feedback due to massive star-formation in the quasar host. Forthcoming mid-infrared spectroscopy with the James Webb Space Telescope will help constrain the physical conditions in quasar hosts further.

The evolution of star formation properties of galaxies depends on the environment where galaxies reside, and generally star formation of galaxies in dense environment decreases more quickly. Interestingly, the star formation property of high-redshift galaxies clusters vary largely even though they are at similar redshift. We have found that the large-scale environment surrounding each galaxy cluster can contribute to make this cluster-by-cluster variation. This correlation is found in the results from observational data as well as in the simulations of galaxy formation. We suggest the ‘Web-feeding model’ to explain this trend. Star-forming galaxies falling into the galaxy cluster from surrounding large-scale structure make the quiescent galaxy fraction of the cluster lower than relatively isolated clusters.

Due to observational constraints, our detailed knowledge of stellar populations, formation, and evolution of galaxies is limited to a few dozen galaxies located in the Local Group. The Local Group of galaxies offers a unique opportunity to construct the formation histories and probe the structure and dynamics of many dwarf galaxies surrounding the Milky Way and Andromeda and of isolated dwarf galaxies. In this regard, we monitored the majority of galaxies in the Local Group, including the M33 galaxy and satellites galaxies surrounding the Milky Way and Andromeda galaxy, as well as isolated dwarf galaxies. We identified stellar populations and based on light curve analysis, the cool evolved stars pulsating in the fundamental mode were identified. In this paper, first, we will present the results we obtained for SFH and dust production rate in individual galaxies separately to answer how different types of galaxies have been formed and evolved over cosmic time. Then, we will discuss whether the mass return from dusty evolved stars can provide enough gas reservoirs to sustain the star formation or even rejuvenate the dwarf galaxy, as some seem to harbor relatively young stars.

We present an overview of the project “The Physics of Galaxy Assembly: IFS observations of high-z galaxies”, a Guaranteed Time Observations (GTO) programme of the James Webb Space Telescope (JWST). It an ambitious project aimed at investigating the internal structure of distant galaxies with the NIRSpec integral field spectrograph (IFS), having allocated 273 hours of JWST prime time. The NIRSpec capability will provide us with spatially resolved spectroscopy in the 1-5 μm range of a sample of over forty galaxies and Active Galactic Nuclei in the redshift range 3 < z 9. IFS observations of individual galaxies will enable us to investigate in detail the most important physical processes driving galaxy evolution across the cosmic epoch. More in detail, the main specific objectives are: to trace the distribution of star formation, to map the resolved properties of the stellar populations, to trace the gas kinematics (i.e. velocity fields, velocity dispersion) and, hence, determine dynamical masses and also identify non-virial motions (outflow and inflows), and to map metallicity gradients and dust attenuation.

The main goal of the Vera C. Rubin observatory is to perform the 10 year Legacy Survey of Space and Time (LSST). This future state-of-art observatory will open the new window to study billions of galaxies from Local Universe as well as the high redshift objects. In this work we employ simulated LSST observations and uncertainties, based on the 50 385 real galaxies within the redshift range 0 < z < 2.5 from the ELAIS-N1 and COSMOS fields of the Herschel Extragalactic Legacy Project (HELP) survey, to constrain the physical properties of normal star-forming galaxies, such as their star formation rate (SFR), stellar mass (Mstar), and dust luminosity (Ldust). We fit their spectral energy distributions (SEDs) using the Code Investigating GALaxy Emission (CIGALE). The stellar masses estimated based on the LSST measurements agree with the full UV to far-IR SED, while we obtain a clear overestimate of the dust-related properties (SFR, Ldust) estimated with LSST. We investigate the cause of this result and find that it is necessary to employ auxiliary rest-frame mid-IR observations, simulated UV observations, or the far-UV attenuation (AFUV)-Mstar relation to correct for the overestimate.

In the standard cosmological model of galaxy evolution, mergers and interactions play a fundamental role in shaping galaxies. Galaxies that are currently isolated are thus interesting, allowing us to identify how internal or external processes impact galactic structure. However, current observational limits may be obscuring crucial information in the low-mass or low-brightness regime. We use the AMIGA catalog of isolated galaxies to explore the impact of different factors on the structure of these galaxies. In particular, we study the type of disk break based on the degree of isolation and the presence of interactions which are only detectable in the ultra-low surface brightness regime. We present the first results of an extensive observational campaign of ultra-deep optical imaging targeting a sample of 25 low-redshift (z < 0.035) isolated galaxies. The nominal surface brightness limits achieved are comparable to those to be obtained in the 10-year LSST coadds ( mag arcsec−2; 3σ ; 10” × 10”). We find that isolated galaxies have a considerably higher fraction of purely exponential disk profiles and a lower presence of up-bending breaks than field or cluster galaxies. Our extreme imaging depth allows us to detect the presence of previously unreported interactions with minor companions in some of the galaxies in our sample (∼40% of the galaxies show signs of interaction). The results of our work fit with the general framework of galactic structure in which up-bending breaks (Type III) would be produced by mergers and down-bending breaks (Type II) due to a threshold in star formation that would tend to become single exponential disk (Type I) in case of cessation or decrease of star formation.