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.

We investigate rest-frame UV to far-infrared emission lines and SEDs from 1124 galaxies at z = 4.9 – 7.0. Our sample is composed of 1092 Lyα emitters (LAEs) at z = 4.9–7.0 identified by Subaru/Hyper Suprime-Cam (HSC) narrowband surveys and 34 galaxies at z = 5.148–7.508 with deep [Cii]158μm ALMA data. The SEDs clearly show flux excesses in the Spitzer/IRAC 3.6 and 4.5μm bands, suggesting strong rest-frame optical emission lines of [Oiii] and/or Hα. We model the galaxy SEDs with a flexible code combining stellar population and photoionization models (BEAGLE; Chevallard & Charlot 2016), and investigate relations between the emission lines of Lyα, [Oiii], Hα, and [CII]. We find 1) a positive correlation between the rest-frame Hα equivalent width (EW) and the Lyα, EW, ${\EW {^0_Ly\alpha}} $, 2) an interesting turn-over trend that the [Oiii]/Hα flux ratio increases in ${\EW {^0_Ly\alpha}} $ ≃ 0–30 Å, and then decreases out to ${\EW {^0_Ly\alpha}} $ ≃ 130 Å, and 3) a > 99% anti-correlation between a [Cii] luminosity to star-formation rate ratio L[Cii]/SFR) and ${\EW {^0_Ly\alpha}} $. Modeling with BEAGLE also suggests that a simple anticorrelation between ${\EW {^0_Ly\alpha}} $ and metallicity explains self-consistently all of the relations of Lyα, Hα, [Oiii]/Hα, and [Cii] in our study, indicative of detections of very metal-poor (∼0.03Z⊙) galaxies with ${\EW {^0_Ly\alpha}} $ ∼200 Å.

XDCPJ0044.0-2033 is one of the most massive galaxy cluster at z ∼1.6, for which a wealth of multi-wavelength photometric and spectroscopic data have been collected during the last years. I have reported on the properties of the galaxy members in the very central region (∼ 70kpc × 70kpc) of the cluster, derived through deep HST photometry, SINFONI and KMOS IFU spectroscopy, together with Chandra X-ray, ALMA and JVLA radio data.

In the core of the cluster, we have identified two groups of galaxies (Complex A and Complex B), seven of them confirmed to be cluster members, with signatures of ongoing merging. These galaxies show perturbed morphologies and, three of them show signs of AGN activity. In particular, two of them, located at the center of each complex, have been found to host luminous, obscured and highly accreting AGN (λ = 0.4−0.6) exhibiting broad Hα line. Moreover, a third optically obscured type-2 AGN, has been discovered through BPT diagram in Complex A. The AGN at the center of Complex B is detected in X-ray while the other two, and their companions, are spatially related to radio emission. The three AGN provide one of the closest AGN triple at z > 1 revealed so far with a minimum (maximum) projected distance of 10 kpc (40 kpc). The discovery of multiple AGN activity in a highly star-forming region associated to the crowded core of a galaxy cluster at z ∼ 1.6, suggests that these processes have a key role in shaping the nascent Brightest Cluster Galaxy, observed at the center of local clusters. According to our data, all galaxies in the core of XDCPJ0044.0-2033 could form a BCG of M* ∼ 1012Mȯ hosting a BH of 2 × 108−109Mȯ, in a time scale of the order of 2.5 Gyrs.

Despite significant progress over the past decades, all state-of-the-art population synthesis (PS) codes suffer from deficiencies limiting their potential of gaining sharp insights into the star formation history (SFH) and Chemical Enrichment History (CEH) of star-forming galaxies, i.e. the neglect of nebular continuum and, the lack of a mechanism to ensure consistency between the best-fitting SFH and the observed nebular characteristics (ONC; Balmer-lines, Balmer/Paschen jumps). These introduce biases in their recovered physical properties (stellar mass M* and sSFR). FADO is a novel self-consistent PS code employing genetic optimization, publicly available (http://www.spectralsynthesis.org), capable of identifying the SFH & CEH that reproduce the ONC of a galaxy, alleviating degeneracies in the spectral fits. The current version of FADO (v1.b) uses standard BPT emission-line ratios for the classification of low redshift (z) galaxies. Whereas this permits a reliable distinction between star-forming, Composite, Seyfert and LINERs, it is inapplicable to many intermediate-z galaxies. We present an adaptation of FADO (version v1.c) to classify higher z galaxies employing the “Blue Diagram” (e.g., Lamareille 2010) for which the most prominent blue emission-lines (< [OIII]5007Å) are observable while the Hα and [NII] are inaccessible. FADO v1.c was applied to synthetic spectra simulating the evolution of galaxies formed at higher-z with different SFHs. FADO can recover the physical and evolutionary properties of galaxies, such as M* and mean age/metallicity, with an accuracy significantly better than purely-stellar codes. An outline of FADO v1.c and applications to local and intermediate-z galaxies will be presented.

By examining Herschel images in the HerMES & H-ATLAS surveys at the position of Planck Catalog of Compact Source sources we are able to determine the nature of the Planck sources. Most are simply nearby, known, dusty galaxies, while others are foreground galactic ‘cirrus’ dust. About 11% of sources, though, appear to be groups or clumps of fainter Herschel objects. Followup of a number of these indicates that they are galaxy clusters or protoclusters at z ~1-3 that contain a number of galaxies undergoing contemporaneous massive starbursts. These sources present challenges for current galaxy & cluster formation/evolution models.

Accretion of gas from the cosmic web to galaxy halos and ultimately their disks is a prediction of modern cosmological models but is rarely observed directly or at the full rate expected from star formation. Here we illustrate possible large-scale cosmic HI accretion onto the nearby dwarf starburst galaxy IC10, observed with the VLA and GBT. We also suggest that cosmic accretion is the origin of sharp metallicity drops in the starburst regions of other dwarf galaxies, as observed with the 10-m GTC. Finally, we question the importance of cosmic accretion in normal dwarf irregulars, for which a recent study of their far-outer regions sees no need for, or evidence of, continuing gas buildup.

Cosmological simulations predict that dark matter halos with circular velocities lower than 30 km/s should have lost most of their neutral gas by heating of the ultra-violet background. This is in stark contrast with gas-rich galaxies such as e.g. Leo T, Leo P and Pisces A, which all have circular velocities of ~15 km/s (Ryan-Weber et al. 2008, Bernstein-Cooper et al. 2014, Tollerud et al. 2015). We show that when we include feedback from the first stars into our models, simulated dwarfs have very different properties at redshift 0 than when this form of feedback is not included. Including this Population-III feedback leads to galaxies that lie on the baryonic Tully-Fisher relation over the entire mass range of star forming dwarf galaxies, as well as reproducing a broad range of other observational properties.

We summarise the recent progress in understanding the formation and evolution of globular clusters (GCs) in the context of galaxy formation and evolution. It is discussed that an end-to-end model for GC formation and evolution should capture four different phases: (1) star and cluster formation in the high-pressure interstellar medium of high-redshift galaxies, (2) cluster disruption by tidal shocks in the gas-rich host galaxy disc, (3) cluster migration into the galaxy halo, and (4) the final evaporation-dominated evolution of GCs until the present day. Previous models have mainly focussed on phase 4. We present and discuss a simple model that includes each of these four steps – its key difference with respect to previous work is the simultaneous addition of the high-redshift formation and early evolution of young GCs, as well as their migration into galaxy haloes. The new model provides an excellent match to the observed GC mass spectrum and specific frequency, as well as the relations of GCs to the host dark matter halo mass and supermassive black hole mass. These results show (1) that the properties of present-day GCs are reproduced by assuming that they are the natural outcome of regular high-redshift star formation (i.e. they form according to same physical processes that govern massive cluster formation in the local Universe), and (2) that models only including GC evaporation strongly underestimate their integrated mass loss over a Hubble time.

Using the Horizon-AGN simulation we find a mass dependent spin orientation trend for galaxies: the spin of low-mass, rotation-dominated, blue, star-forming galaxies are preferentially aligned with their closest filament, whereas high-mass, velocity dispersion- supported, red quiescent galaxies tend to possess a spin perpendicular to these filaments. We explore the physical mechanisms driving galactic spin swings and quantify how much mergers and smooth accretion re-orient them relative to their host filaments.

In addition to large numbers of normal galaxies, the multibeam HI Parkes all-sky survey will probably discover intergalactic HI clouds, very low-surface-brightness, gas-rich galaxies, and small HI clouds in nearby groups of galaxies. I will briefly discuss some aspects of why these classes of objects are interesting in the context of dark matter and galaxy formation.

Understanding how galaxies obtain baryons, their stars and gas, over cosmic time is traditionally approached in two different ways - theoretically and observationally. In general, observational approaches to galaxy formation include measuring basic galaxy properties, such as luminosities, stellar masses, rotation speeds, star formation rates and how these features evolve through time. Theoretically, cosmologically based models collate the physical effects driving galaxy assembly - mergers of galaxies, accretion of gas, star formation, and feedback, amongst others, to form predictions which are matched to galaxy observables. An alternative approach is to examine directly, in an observational way, the processes driving galaxy assembly, including the effects of feedback. This is a new ‘third way’ towards understanding how galaxies are forming from gas accretion and mergers, and directly probes these effects instead of relying on simulations designed to reproduce observations. This empirical approach towards understanding galaxy formation, including the acquisition history of baryons, displays some significant differences with the latest galaxy formation models, in addition to directly demonstrating the mechanisms by which galaxies form most of their baryonic mass.

Cosmological models predict that large galaxies like the Milky Way formed from the accretion of smaller stellar systems. The most spectacular of these merger events are stellar tidal streams, rivers of stars and dark matter that envelop the discs of spiral galaxies. We present a research project for a collaboration with amateur astronomers in the study of the formation process of our Galaxy. The main objective is the search for RR Lyrae variable stars in the known stellar streams (Sagitarius, Monoceros, Orphan, etc) a project that can be carried out using small telescopes. The catalogue of candidate variable stars were selected from SDSS data based in colour criteria and it will be sent to interested amateur astronomers who wish to participate in scientific research in one of the most active and competitive topics in Galactic astronomy.

As found in Secco (2000, 2001), the presence of a (non-baryonic) dark halo in large-scale celestial objects, can induce a scale length on the luminous spheroid through the occurrence of an unexpected maximum in the virial potential energy (Clausius Virial, CV). The above mentioned investigations were grounded on two cored power law density profiles, but the same result is shown to hold for more refined and realistic models.

We have used the Hubble Space Telescope's Advanced Camera for Surveys to measure the mass density function of morphologically-selected early-type galaxies in the Gemini Deep Deep Survey fields, over the redshift range 0.9 < z < 1.6. Our imaging data set covers four well-separated sight-lines, and is roughly intermediate (in terms of both depth and area) between the GOODS/GEMS imaging data, and the images obtained in the Hubble Deep Field campaigns. Our images contain 144 galaxies with ultra-deep spectroscopy, and they have been analyzed using a new purpose-written morphological analysis code which improves the reliability of morphological classifications by adopting a ‘quasi-petrosian’ image thresholding technique. We find that at z = 1 approximately 70% of the stars in massive galaxies reside in early-type systems. This fraction is remarkably similar to that seen in the local Universe. However, we detect very rapid evolution in this fraction over the range 1.0 < z < 1.6, suggesting that in this epoch the strong color-morphology relationship seen in the nearby Universe is beginning to fall into place.