Search

We compare the bar fractions as a function of the Hubble sequence by adopting different methods for the same sample (Lee et al.2019). For the same sample with z < 0.01 from SDSS, the visual inspection, ellipse fitting method, and the Fourier analysis detect 63%, 48%, and 36% of barred galaxies. The fractions largely get different as a function of the Hubble sequence. The ellipse fitting method obtains the increasing bar fraction towards late-type spirals, whereas the Fourier analysis releases the opposite tendency, increasing the bar fraction towards early-type spirals. It is because the ellipse fitting method generally misses barred galaxies when the bulge dilutes the ellipticity of the whole galaxy. The bar strength is also differently affected by the algorithm to measure it: the Fourier analysis increases the bar strength when a galaxy has a large bulge. We develop a new method to classify barred galaxies based on their potential map by analyzing the butterfly pattern (Lee et al. 2020). This method detects 53% of barred galaxies including SBs and SABs, which are consistent with the visual inspection by an accuracy of 87%. Finally, we classify barred galaxies into fast, medium, and slow bars by estimating the frequency curves and using the bar pattern speed (Lee et al. 2022). It could provide information for the evolutionary stage of the bar, supporting little evolution of the bar length and strength during the bar evolution., {"references":["Lee, Y. H., Ann, H. B., & Park, M. -G. 2019, ApJ, 872, 97. Bar Fraction in Early- and Late-type Spirals.","Lee, Y. H., Park, M. -G., Ann, H. B., Kim, T., & Seo, W. -Y. 2020, ApJ, 899, 84. Bar Classification Based on the Potential Map","Lee,Y.H.,Park,M.-G.,Hwang,H.S.,et al. 2022, ApJ, 926, 58. Properties of Fast and Slow Bars Classified by Epicyclic Frequency Curves from Photometry of Barred Galaxies"]}

Cluster galaxies exhibit substantially lower star formation rates than field galaxies today, but it is conceivable that clusters were sites of more active star formation in the early universe. Herein, we present an interpretation of the star formation history (SFH) of group/cluster galaxies based on the large-scale cosmological hydrodynamic simulation, Horizon-AGN. We find that massive galaxies in general have small values of e-folding timescales of star formation decay (i.e., ``mass quenching'') regardless of their environment, whilst low-mass galaxies exhibit prominent environmental dependence. In massive host halos (i.e., clusters), the e-folding timescales of low-mass galaxies are further decreased if they reside in such halos for a longer period of time. This ``environmental quenching'' trend is consistent with the theoretical expectation from ram pressure stripping. Furthermore, we define a ``transition epoch'' as where cluster galaxies become less star-forming than field galaxies. The transition epoch of group/cluster galaxies varies according to their stellar and host cluster halo masses. Low-mass galaxies in massive clusters show the earliest transition epoch of $\sim 7.6$ Gyr ago in lookback time. However, it decreases to $\sim 5.2$ Gyr for massive galaxies in low-mass clusters. Based on our findings, we can describe cluster galaxy's SFH with regard to the cluster halo-to-stellar mass ratio., Comment: 17 pages, 10 figures, resubmitted to ApJ following first referee report

We thank the anonymous referee for providing useful comments that improved the quality of the paper. We thank Ian Smail for very helpful discussions. This publication uses data from the ALMA programs: ADS/JAO.ALMA# 2018.1.00035.L, #2013.1.00999.S, and #2015.1.01425.S. ALMA is a partnership of ESO (representing its member states), NSF (USA) and NINS (Japan), together with NRC (Canada), MOST and ASIAA (Taiwan), and KASI (Republic of Korea), in cooperation with the Republic of Chile. The Joint ALMA Observatory is operated by ESO, AUI/NRAO, and NAOJ. This work has been financially supported by JSPS KAKENHI grant Nos. 22J22795 (R.U.), 20H01946 (Y.U.), 17H06130 (K.K., Y.U.), 19K14759 (Y.T.), and 22H01266 (Y. T.), and the NAOJ ALMA Scientific Research grant No. 2017- 06B (K.K.). S.Y. is grateful for support from RIKEN Special Postdoctoral Researcher Program. F.S. acknowledges support from the NRAO Student Observing Support (SOS) award SOSPA7-022. G.E.M. acknowledges the Villum Fonden research grants 13160 and 37440 and the Cosmic Dawn Center of Excellence funded by the Danish National Research Foundation under grant No. 140. H.U. acknowledges support from JSPS KAKENHI under grant No. 20H01953. D.E. acknowledges support from a Beatriz Galindo senior fellowship (BG20/00224) from the Spanish Ministry of Science and Innovation, projects PID2020-114414GB-100 and PID2020-113689GB-I00 financed by MCIN/AEI/ 10.13039/501100011033, project P20_00334 financed by the Junta de Andalucía, and project A-FQM-510-UGR20 of the FEDER/Junta de Andalucía-Consejería de Transformación Económica, Industria, Conocimiento y Universidades, We report the multiwavelength properties of millimeter galaxies hosting X-ray detected active galactic nuclei (AGNs) from the ALMA Lensing Cluster Survey (ALCS). ALCS is an extensive survey of well-studied lensing clusters with ALMA, covering an area of 133 arcmin(2) over 33 clusters with a 1.2 mm flux-density limit of similar to 60 mu Jy (1 sigma). Utilizing the archival data of Chandra, we identify three AGNs at z = 1.06, 2.09, and 2.84 among the 180 millimeter sources securely detected in the ALCS (of which 155 are inside the coverage of Chandra). The X-ray spectral analysis shows that two AGNs are not significantly absorbed (log N-H cm (2) < 23 -), while the other shows signs of moderate absorption (log NH cm (2) similar to 23.5 -). We also perform spectral energy distribution modeling of X-ray to millimeter photometry. We find that our X-ray AGN sample shows both high mass-accretion rates (intrinsic 0.5-8 keV X-ray luminosities of similar to 10(44-45) erg s(-1)) and star formation rates (> 100 Me yr-1). This demonstrates that a wide-area survey with ALMA and Chandra can selectively detect intense growth of both galaxies and supermassive black holes in the high-redshift universe., Ministry of Education, Culture, Sports, Science and Technology, Japan (MEXT) Japan Society for the Promotion of Science Grants-in-Aid for Scientific Research (KAKENHI) A-FQM-510-UGR20, NAOJ ALMA Scientific Research 22J22795, RIKEN Special Postdoctoral Researcher Program, NRAO Student Observing Support (SOS) 20H01946, Villum Fonden 17H06130 19K14759, Cosmic Dawn Center of Excellence - Danish National Research Foundation 22H01266, Ministry of Science and Innovation, Spain (MICINN) Spanish Government, Junta de Andalucia, FEDER/Junta de Andalucia-Consejeria de Transformacion Economica, Industria, Conocimiento y Universidades, MCIN/AEI 2017-06B, SOSPA7-022, 13160, 37440, 140, 20H01953, BG20/00224, PID2020-114414GB-100, PID2020-113689GB-I00, P20_00334

We report the multi-wavelength properties of millimeter galaxies hosting X-ray detected active galactic nuclei (AGNs) from the ALMA Lensing Cluster Survey (ALCS). ALCS is an extensive survey of well-studied lensing clusters with ALMA, covering an area of 133 arcmin$^2$ over 33 clusters with a 1.2 mm flux-density limit of ${\sim}$60 $\mathrm{\mu Jy}$ ($1\sigma$). Utilizing the archival data of Chandra, we identify three AGNs at $z=$1.06, 2.09, and 2.84 among the 180 millimeter sources securely detected in the ALCS (of which 155 are inside the coverage of Chandra). The X-ray spectral analysis shows that two AGNs are not significantly absorbed ($\log N_{\mathrm{H}}/\mathrm{cm}^{-2} < 23$), while the other shows signs of moderate absorption ($\log N_{\mathrm{H}}/\mathrm{cm}^{-2}\sim 23.5$). We also perform spectral energy distribution (SED) modelling of X-ray to millimeter photometry. We find that our X-ray AGN sample shows both high mass accretion rates (intrinsic 0.5--8 keV X-ray luminosities of ${\sim}10^{\text{44--45}}\,\mathrm{erg\ s^{-1}}$) and star-formation rates (${\gtrsim}100\,M_{\odot}\,\mathrm{yr}^{-1}$). This demonstrates that a wide-area survey with ALMA and Chandra can selectively detect intense growth of both galaxies and supermassive black holes (SMBHs) in the high-redshift universe., Comment: 14 pages, 3 figures, 2 tables

Galaxy evolution is an interplay of physical processes across a wide range of cosmological size scales, from star formation and black hole growth on sub-pc scales, to interactions with their environments on Mpc scales. The region surrounding individual galaxies within their host halos is known as the Circumgalactic Medium (CGM), and connects galaxies to the wider Intergalactic Medium (IGM). The CGM acts as both a reservoir of inflowing gas and a repository for outflowing gas as it is transported outwards via galactic feedback. Quasar absorption line surveys have revealed the CGM to be a complex, multiphase environment in which ions tracing cool and hot gas are present within the same absorber systems. Cosmological simulations are a powerful tool for building a theoretical understanding of these interconnected processes and resulting observations. They provide a 3D view of galaxies and their host halos, in which we intrinsically know the physical conditions of the constituent dark matter and baryons. As such, simulations are useful both for testing galaxy evolution models against the real universe, and for interpreting complex observations in a physical context. In this thesis I present detailed comparisons of simulations to observations of star formation and quenching in galaxies, and of absorbers in galactic halos in an effort to constrain physical models. I use Simba, a suite of state of the art cosmological simulations with realistic sub-grid physical models based on high resolution zoom simulations, including novel treatments of dust evolution and of black hole growth and feedback. I investigate the nature of gas in galaxies and their halos, and show comparisons with observations. In addition, I isolate the impacts of galactic feedback and ionising radiation on the results by varying elements of the input physical models. In Chapter 3, I present radial profiles of star forming and green valley galaxies in Simba at z=0 and compare with observations of MaNGA spatially resolved spectroscopy. My analysis shows strong central depressions in star formation rate (SFR), specific SFR (sSFR), and gas fraction in Simba's green valley galaxies and massive star-forming systems, qualitatively as] observed, owing to Active Galactic Nuclei (AGN) X-ray feedback, which pushes central gas radially outwards. These effects are less pronounced at higher redshift, owing to less powerful AGN feedback. I also present a comparison of galaxy half light radii to observations at various redshifts, finding that predictions for star-forming galaxy sizes are accurate but that quenched galaxies are impacted by numerical heating. In Chapter 4, I characterise the low redshift CGM in Simba and examine the impact of differing feedback prescriptions. Low mass galaxies live in multiphase, diverse halos, whereas high mass galaxies live in halos dominated by hot gas. Halo baryon fractions are generally < 50% of the cosmic fraction due to stellar feedback at low masses, and 'jet-mode' AGN feedback at high masses. I present a comparison of absorption statistics to the COS-Halos and COS-Dwarfs surveys: Simba reproduces HI absorption well around star forming galaxies and broadly reproduces absorption of selected metal lines, including the observed dichotomy in OVI absorption between star forming and quenched galaxies. These predictions of metal line absorption are sensitive to the choice of photo-ionising background. Varying the galactic feedback prescription shows that stellar feedback enriches the CGM, while AGN feedback sets the gas temperature phase. In Chapter 5 I extend this analysis with a theoretical perspective of the CGM in Simba using a sample of CGM absorbers from a representative sample of Simba galaxies, selected across a range of stellar masses and sSFR. Absorbers are more abundant around low mass, star forming galaxies; the CGM of green valley galaxies is more similar to that of quenched galaxies. The absorber overdensity depends on the sSFR of the galaxy, while the absorber temperature is set by galaxy stellar mass. Absorption from low ions arises from cold, dense CGM gas, whilst absorption from higher ions traces hotter, more diffuse gas. I also examine the proportion of absorption arising from collisionally ionised gas, and from gas that is associated with satellite galaxies. Finally, in Chapter 6 I develop a tree-based machine learning mapping between the observable properties and the underlying physical conditions of the absorbers in the CGM absorber sample from Chapter 5. Such a mapping has the potential to be used to interpret CGM observations within a full cosmological context, assuming the Simba galaxy evolution model.

Väitekirja elektrooniline versioon ei sisalda publikatsioone, Me teame praegu üsna hästi, kui palju tavalist ainet (st barüone) peab universumis olema: umbes viis protsenti kogutihedusest. Ülejäänu on salapärane tume aine ja tumeenergia. Kuid üllatavalt, meie lähi- universumis on ka ligikaudu pool barüonidest jäänud senini vaatlustes tabamata. Seda erinevust oodatava ja reaalselt vaadeldud barüonide osakaalude vahel nimetatakse puuduvate barüonide probleemiks. Kuna puuduvate barüonide tekitatav vaatluslik signaal jääb allapoole meie instrumentide tundlikkuse läve, siis tundub vastuolu olevat eelkõige vaatluslik. Seetõttu kasutasime antud töös puuduolevate barüonide jaotuse ja termodünaamiliste omaduste teoreetiliseks uurimiseks kosmoloogilist numbrilist simulatsiooni EAGLE. Varasemates teoreetilistes uuringutes oli saadud, et puudu olevad barüonid asuvad kosmilistes filamentides olevas kuumas galaktikatevahelises gaasis. Me jätkasime neid töid, kasutades filamentide võrgustiku leidmiseks erinevaid algoritme, näiteks Bisous meetodit. Seejärel kirjeldasime sel viisil leitud filamentides paiknevat kuuma galaktikavahelist gaasi. Arvestades, et galaktikad ja galaktikatevaheline gaas eksisteerivad üheskoos nendes samades suuremastaabilise struktuuri elementides, uurisime lisaks ka simulatsioonides genereeritud galaktikate heleduste jaotust. See võimaldas meil saada optimaalse filamentide valimi, kus puuduvate barüonide tihedused olid suurimad. Ehk sisuliselt, parimad kohad praegu veel vaatluslikult leidmata tavalise aine otsimiseks on filamentide südamikud, mis asuvad suure galaktikate heledustiheduse piirkondades. Töös uurisime ka võimalust kasutada puuduvate barüonide leidmiseks kõrgelt ioniseeritud hapnikku. Kuna OVII on vaadeldav röntgen- lainepikkustel, on seda iooni võimalik kasutada kuuma galaktikavahelise gaasi leidmiseks. Kahjuks ei olnud meie EAGLE simulatsiooni uuringu tulemuste põhjal filamentides piisavalt kogus OVII ioone, et leida puuduvaid barüone. Sellegipoolest on meie töös saadud tulemustest kosmiliste filamentide puuduvate barüonide ja OVII jaotuse kohta abi tulevaste röntgenvaatluste planeerimisel., Currently, we have a good understanding of how much ordinary matter (i.e. baryons) there is in the Universe: ~5%. The rest are the mysterious dark matter and energy. However, in the nearby Universe, half of the baryons remain unobserved. This discrepancy between the expected and observed baryon fractions is known as the problem of the missing baryons. Since the observational signal of the missing baryons falls below the sensitivity of our instruments, the problem is seemingly of an observational nature. Thus, we used the cosmological simulation EAGLE to gain theoretical understanding of the distribution and thermodynamic properties of the missing baryons. Earlier theorethical studies concluded that the missing baryons are in the hot intergalactic gas, residing within cosmic filaments. We continued upon this by applying algorithms, such as the Bisous method, to detect this filamentary network. We then characterised the hot intergalactic gas within the detected filaments. In addition, given that galaxies and the intergalactic gas co-exist in the same large-scale structures, we studied the distribution of the luminosities of simulated galaxies. This allowed us to select a sample of optimal filaments, containing the highest densities of missing baryons. In essence, the best regions to search for the yet unobserved ordinary matter is in the cores of filaments, located in regions with a high density of galaxy luminosity. Finally, we studied the prospect of using highly ionised Oxygen to trace the missing baryons. Being observable in the X-ray range, OVII is a candidate to track the hot intergalactic gas. Unfortunately, based on our results on the EAGLE simulation, there is not enough OVII in filaments to trace the missing baryons. Nonetheless, the results presented in our work on the distribution of both the missing baryons and OVII within cosmic filaments will aid in planning future X-ray observations., https://www.ester.ee/record=b5539906

The study of gaseous haloes holds the key to understanding gas flows in and out of galaxies, which in turn determines how galaxies form and evolve. However, recent observations have revealed them to be very complex, with the presence of significant amounts of multiphase gas, driven by a range of physical process within galaxies as well as by the larger-scale environment. Simulations that realistically model this gas are therefore crucial to interpreting this new data, and ultimately helping us understand how galaxies assemble. However, many cosmological simulations sacrifice resolution in gaseous haloes to reduce their computational cost, meaning their ability to accurately resolve some of the key physical processes, such as turbulence and instabilities, can be limited. Using cosmological simulations, in this thesis I have investigated how gaseous haloes evolve over time. I have implemented a new shock refinement scheme to boost numerical resolution in gaseous haloes. Applied to a massive cluster progenitor, I found significant increases in cold gas mass in filaments and clumps, leading to more widespread star formation. In the hot halo there is a notable boost in turbulent velocities, leading to a doubling of non-thermal pressure support. With the FABLE suite, I studied how the hydrostatic mass bias and turbulent pressure support level in galaxy clusters change as they undergo major mergers and are host to powerful feedback episodes. I found that clusters rarely tend to be in hydrostatic equilibrium for long, with variations being driven by both merger activity and interestingly, at higher redshift, AGN feedback. Such insights could be important for future cluster mass estimates from X-ray and SZ observations, for use as cosmological probes. Finally, I simulated the growth of an ultramassive black hole of mass ∼ 10^10 M⊙ by z = 6. I have studied its impact on the gaseous halo around it, including how powerful AGN feedback can disrupt inflowing cold filaments and increase the thermal pressure of the surrounding gas. I found that strong AGN-driven outflows can deposit significant quantities of metals at very large distances from the central galaxy, which could be a unique signature of the presence of such ultramassive black holes in the very early Universe. Many of the effects predicted by the simulations described in this thesis have the potential to be observed (or ruled out) in the coming decade or two, with an incoming wealth of observational data from observatories like JWST, Athena, CMB-S4, SKA, and LISA. These data, combined with further developments in theory and simulation, will therefore revolutionise our understanding of gaseous haloes., STFC European Research Council

We examine the origin of molecular gas heating in a sample of 42 infrared-luminous galaxies at z

The paper considers the problem of spatio-temporal modeling of the Galaxy and the computational approach for a solution to the Fermi paradox. A sequence of operations for creating the Milky Way grid model MWG has been developed. It includes star sites, tetrahedral meshes and a volume grid with interpolation blocks. The nearest galactic block of the solar neighborhood by size of 103 ly is constructed based on the astronomical data from the Gaia satellite telescope catalog. In parallel a stochastic Monte Carlo model is used for the same region, and its stellar composition and distribution density is adjusted to fit astronomical data. Extrapolation to the rest of the MWG model with 106 blocks is performed taking into account the peculiarities of its spiral structure and volume inhomogeneities for the galaxy habitable zone GHZ. An equation for the convolution of birth and death functions is proposed with the inclusion of an evolution filter calculated in accordance with the spectral composition of stars. Finding the shortest paths and optimal communications between remote planetary systems is proposed to be computed both on a tetrahedral grid and on a uniform block model. The results are aimed at evaluating the existense of biospheres and technospheres for the SETI programs which should be targeted to the potential habitable ring loci inside the Galaxy disc.

In an aging stellar population, the number fractions of chemically peculiar (CP) stars rise and fall periodically, and the fractions are high enough that their spectra features survive to appear in integrated light at subtle levels. Chemically peculiar stars are suggested to be used to disentangle an age history from integrated light spectroscopy. In this dissertation, we first introduce the improvement on stellar evolutionary isochrones and composite stellar population models. Individual elements C, N, O, Mg, Si, and Fe were included to gauge the effects on temperatures, luminosities, and lifetimes in various phases. Then, Integrated-light models that incorporate common types of chemically peculiar stars are assembled using synthetic spectra. CP spectra features are analyzed for local group galaxies and SDSS galaxies. Finally, we attempt to build an age technique with CP features. Four indices are defined from HgMn spectra features. Two age indicators are constructed and applied to SDSS galaxies for analysis of star formation history.

Attempts to trace star formation with rest-frame UV/optical observations at redshifts z > 2 are affected by the presence of potentially substantial, yet uncertain, dust attenuation. Recent studies have demonstrated the existence of a population of galaxies that are virtually invisible in the observed optical/near-infrared (NIR) due to dust obscuration, but which could contribute substantially to the star formation history at 2 < z < 6. Here, we make use of ultradeep 3 GHz Karl G. Jansky Very Large Array observations from the COSMOS-XS survey to investigate the contribution 20of radio-selected "optically dark" galaxies (undetected to a depth of KS ∼ 25.9 mag) to the cosmic star formation rate density (SFRD). We identify 19 such "optically dark" sources and utilize recent deblended far-infrared photometry to determine photometric redshifts based on IR and radio information for 11 of them. Through stacking, we infer that the remaining eight sources reside predominantly at high redshift (z > 4). Therefore, we conservatively assume these sources lie between z = 2 and z = 5. We derive the radio luminosity function (LF) for the sample with and without "optically dark" sources by fixing the faint and bright end shape of the radio LF to the local values and allowing for luminosity evolution.

We report on the search for the 7Be ii isotope in the outbursts of the classical nova V6595 Sgr by means of high-resolution Ultraviolet and Visual Echelle Spectrograph (UVES) observations taken at the European Southern Observatory's Very Large Telescope in 2021 April, about two weeks after its discovery and under difficult circumstances due to the pandemic. Narrow absorption components with velocities at -2620 and-2820 km s-1, superposed on broader and shallow absorption, are observed in the outburst spectra for the 7Be ii λλ313.0583, 313.1228 nm doublet resonance lines, as well as in several other elements such as Ca ii, Fe i, Mg i, Na i, H i and Li i. Using the Ca ii K line as a reference element, we infer N(7Be)/N(H) ≈ 7.4 × 10-6, or ≈ 9.8 × 10-6 when the 7Be decay is taken into account. The 7Be abundance is about half of the value most frequently measured in novae. The possible presence of overionization in the layers where 7Be ii is detected is also discussed. Observations taken at the Telescopio Nazionale Galileo in La Palma 91 days after discovery showed prominent emission lines of oxygen and neon, which allow us to classify the nova as ONe type. Therefore, although 7Be is expected to be higher in CO novae, it is found at comparable levels in both nova types., LI was supported by two grants from VILLUM FONDEN (project number 16599 and 25501). M. H. acknowledges support from grant PID2019-108709GB-100 from MICINN (Spain).

Cüce Eliptik Galaksiler (dwarf elliptical galaxies, dEs) galaksi küme evrimini anlamak için anahtar rol oynarlar. Bu çalışmada SMAKCED (Stellar content, MAss and Kinematics of Cluster Early-type Dwarf galaxies) projesinin bir parçası olarak Virgo galaksi kümesinde salt parlaklığı -19.0 < M$_r$ < -16.0 aralığında bulunan 37 dEs’nin yıldızlararası pupülasyon ve element bolluğu hesaplanmıştır. Yıldızlararası popülasyon analizi, yüksek çözünürlüklü tayfsal veriler ışığında soğurma çizgi genişlik indekslerin ölçülmesi, indeks-indeks diyagramları, temel parametre bağıntıları ve yıldızlararası popülasyon modellerinin kullanılması ile elde edilmiştir. Bu galaksilere ait yaş, metallik ve element bolluğu ${R}_{e}$/8 açıklığı içerisinde saptanmıştır. Bolluk analizinde [Na/Fe] NaD, [Ca/Fe] Ca4227 ve [Mg/Fe] Mgb çizgi indeksileri kullanılarak hesaplanmıştır. Bu hesaplamaların ışığında $\alpha$ elementi olan [Mg/Fe] güneş bolluğunda iken [Na/Fe] ın daha az bollukta olduğu tespit edilmiştir. Bu durum dev eliptiklerde bulunan durumun tamamen zıttıdır, ama bu trend NGC1396 Fornax cücesinin önceki çalışmaları ile uyum içerisindedir.Bu tür bolluk düzenlerine neden olabilecek olası senaryolar tartışılmış ve dE’lerin geç tip cüceler veya küçük spirallerden oluşabileceği disk benzeri yıldız oluşum tarihçelerine (Star Formation History, SFH) sahip olabileceği öngörüsünde bulunulmuştur. Na-verimliliği yıldızlardaki nötron fazlalığından dolayı metalliğe bağımlıdır. dEs önemli ölçüde kimyasal evrim geçirdikleri ve bu nedenle tek düze, yaşlı olmadıkları ancak Yerel Grup galaksilerin çoğuna benzer şekilde genişletilmiş SFH sahip olduğu sonucuna varılmıştır., We define abundance ratios of 37 dwarf ellipticals (dEs) in the nearby Virgo cluster. This sample is representative of the early-type population of galaxies in the absolute magnitude range -19.0 < M$_r$ < -16.0. We analyze their absorption line-strength indices by means of index-index diagrams and scaling relations and use the stellar population models to interpret them. We present ages, metallicities and abundance ratios obtained from these dEs within an aperture size of ${R}_{e}$/8. We calculate [Na/Fe] from NaD, [Ca/Fe] from Ca4227 and [Mg/Fe] from Mgb. We find that [Na/Fe] is under-abundant with respect to solar while [Mg/Fe] is around solar. This is exactly opposite to what is found for giant ellipticals, but follows the trend with metallicity found previously for the Fornax dwarf NGC 1396. We discuss possible formation scenarios that can result in such elemental abundance patterns and we speculate that dEs have disk-like SFH favouring them to originate from late-type dwarfs or small spirals.Na-yields appear to be very metal-dependent, in agreement with studies of giant ellipticals, probably due to the large dependence on the neutron-excess in stars. We conclude that dEs have undergone a considerable amount of chemical evolution, they are therefore not uniformly old, but have extended SFH, similar to many of the Local Group galaxies.

The origin and evolution of galaxies are closely linked to many different physical phenomena. Among them, the most important one is the environment they reside in. Isolated and cluster member galaxies indeed are affected by different forces which affect their evolution. The main concern of this thesis is to understand such forces and how they are related to galaxy evolution. Therefore, this thesis covers various topics including black hole mass calculations, the black hole mass-stellar velocity dispersion relation, the nature of AGN emission in galaxy clusters and field galaxies, a detailed investigation of X-ray and optical galaxy overdensity phenomenon, and the dynamical processes in pre-merging galaxy clusters.

The origin and evolution of galaxies are closely linked to many different physical phenomena. Among them, the most important one is the environment they reside in. Isolated and cluster member galaxies indeed are affected by different forces which affect their evolution. The main concern of this thesis is to understand such forces and how they are related to galaxy evolution. Therefore, this thesis covers various topics including black hole mass calculations, the black hole mass-stellar velocity dispersion relation, the nature of AGN emission in galaxy clusters and field galaxies, a detailed investigation of X-ray and optical galaxy overdensity phenomenon, and the dynamical processes in pre-merging galaxy clusters.

We present a joint analysis of the galaxy S04590 at z = 8.496 based on NIRSpec, NIRCam, and NIRISS observations obtained as part of the Early Release Observations program of the James Webb Space Telescope (JWST) and the far-infrared [C ii] 158 mu m emission line detected by dedicated Atacama Large Millimeter/submillimeter Array (ALMA) observations. We determine the physical properties of S04590 from modeling of the spectral energy distribution (SED) and through the redshifted optical nebular emission lines detected with JWST/NIRSpec. The best-fit SED model reveals a low-mass (M-? = 10(7.2)-10(8) M-?) galaxy with a low oxygen abundance of derived from the strong nebular and auroral emission lines. Assuming that [C ii] effectively traces the interstellar medium, we estimate the total gas mass of the galaxy to be M-gas = (8.0 +/- 4.0) x 10(8) M-? based on the luminosity and spatial extent of [C ii]. This yields an exceptionally high gas fraction, f(gas) = M-gas/(M-gas + M-?) ? 90%, though one still consistent with the range expected for low metallicity. We further derive the metal mass of the galaxy based on the gas mass and gas-phase metallicity, which we find to be consistent with the expected metal production from Type II supernovae. Finally, we make the first constraints on the dust-to-gas (DTG) and dust-to-metal (DTM) ratios of galaxies in the epoch of reionization at z ? 6, showing overall low mass ratios of logDTG < -3.8 and logDTM < -0.5, though they are consistent with established scaling relations and in particular with those of the local metal-poor galaxy I Zwicky 18. Our analysis highlights the synergy between ALMA and JWST in characterizing the gas, metal, and stellar content of the first generation of galaxies., Carlsberg Foundation Reintegration Fellowship CF21-0103, VILLUM FONDEN through the Villum Experiment Programme, Carlsberg Foundation 17H06130, Ministry of Education, Culture, Sports, Science and Technology, Japan (MEXT) Japan Society for the Promotion of Science, Grants-in-Aid for Scientific Research (KAKENHI) NAS 5-03127, NAOJ ALMA Scientific Research, Association of Universities for Research in Astronomy, Inc., under NASA 2017-06B, Danmarks Grundforskningsfond CF20-0534 140

We present a set of multiwavelength mosaics and photometric catalogs in the Atacama Large Millimeter/ submillimeter Array (ALMA) lensing cluster survey fields. The catalogs were built by the reprocessing of archival data from the Complete Hubble Archive for Galaxy Evolution compilation, taken by the Hubble Space Telescope (HST) in the Reionization Lensing Cluster Survey, Cluster Lensing And Supernova survey with Hubble, and Hubble Frontier Fields. Additionally, we have reconstructed the Spitzer Infrared Array Camera 3.6 and 4.5 μm mosaics, by utilizing all the available archival IPAC Infrared Science Archive/Spitzer Heritage Archive exposures. To alleviate the effect of blending in such a crowded region, we have modeled the Spitzer photometry by convolving the HST detection image with the Spitzer point-spread function using the novel GOLFIR software. The final catalogs contain 218,000 sources, covering a combined area of 690 arcmin2, a factor of ∼2 improvement over the currently existing photometry. A large number of detected sources is a result of reprocessing of all available and sometimes deeper exposures, in conjunction with a combined optical–near-IR detection strategy. These data will serve as an important tool in aiding the search of the submillimeter galaxies in future ALMA surveys, as well as follow-ups of the HST dark and high-z sources with JWST. Coupled with the available HST photometry, the addition of the 3.6 and 4.5 μm bands will allow us to place a better constraint on the photometric redshifts and stellar masses of these objects, thus giving us an opportunity to identify high-redshift candidates for spectroscopic follow-ups and to answer the important questions regarding the Epoch of Reionization and formation of the first galaxies. The mosaics, photometric catalogs, and the best-fit physical properties are publicly available at https:// github.com/dawn-cph/alcs-clusters., Danmarks Grundforskningsfond 140, Villum Fonden 13160 37440, Carlsberg Foundation CF18-0388, European Commission 896225 European Research Council (ERC) European Commission 648179, Ministry of Education, Culture, Sports, Science and Technology, Japan (MEXT) Japan Society for the Promotion of Science, Grants-in-Aid for Scientific Research (KAKENHI) JP17H06130, NAOJ ALMA Scientific Research 2017-06B, NRAO Student Observing Support (SOS) SOSPA7-022, Beatriz Galindo senior fellowship BG20/00224, Ministry of Science and Innovation, Spain (MICINN) PID2020-114414GB-100 PID2020-113689GB-I00, Junta de Andalucia P20_00334 FEDER/Junta de Andalucia-Consejeria de Transformacion Economica, Industria, Conocimiento y Universidades -FQM-510-UGR20, RELICS Treasury Program GO 14096, National Aeronautics & Space Administration (NASA) NAS5-26555

We report the discovery of a candidate galaxy with a photo-z of z~12 in the first epoch of the JWST Cosmic Evolution Early Release Science (CEERS) Survey. Following conservative selection criteria we identify a source with a robust z_phot = 11.8^+0.3_-0.2 (1-sigma uncertainty) with m_F200W=27.3, and >7-sigma detections in five filters. The source is not detected at lambda < 1.4um in deep imaging from both HST and JWST, and has faint ~3-sigma detections in JWST F150W and HST F160W, which signal a Ly-alpha break near the red edge of both filters, implying z~12. This object (Maisie's Galaxy) exhibits F115W-F200W > 1.9 mag (2-sigma lower limit) with a blue continuum slope, resulting in 99.6% of the photo-z PDF favoring z > 11. All data quality images show no artifacts at the candidate's position, and independent analyses consistently find a strong preference for z > 11. Its colors are inconsistent with Galactic stars, and it is resolved (r_h = 340 +/- 14 pc). Maisie's Galaxy has log M*/Msol ~ 8.5 and is highly star-forming (log sSFR ~ -8.2 yr^-1), with a blue rest-UV color (beta ~ -2.5) indicating little dust though not extremely low metallicity. While the presence of this source is in tension with most predictions, it agrees with empirical extrapolations assuming UV luminosity functions which smoothly decline with increasing redshift. Should followup spectroscopy validate this redshift, our Universe was already aglow with galaxies less than 400 Myr after the Big Bang., 17 pages, 6 figures, 3 tables, ApJL in press. Summary of changes from original submission: Improvements in astrometry generated a weak detection in F150W that reduces the photo-z to 11.8 but does not increase the likelihood of lower-z solutions. A full discussion of changes from the original version is available at: https://web.corral.tacc.utexas.edu/ceersdata/papers/Maisie_update.pdf

In recent years, Galactic archaeology has become a particularly vibrant field of astronomy, with its main focus set on the oldest stars of our Galaxy. In most cases, these stars have been identified as the most metal-poor. However, the struggle to find these ancient fossils has produced an important bias in the observations - in particular, the intermediate metal-poor stars (-2.5, 21 pages, 23 figures, online material. Accepted for publication in A&A

The first few 100 Myr at z > 10 mark the last major uncharted epoch in the history of the universe, where only a single galaxy (GN-z11 at z ≈ 11) is currently spectroscopically confirmed. Here we present a search for luminous z > 10 galaxies with JWST/NIRCam photometry spanning ≈1–5 μm and covering 49 arcmin2 from the public JWST Early Release Science programs (CEERS and GLASS). Our most secure candidates are two MUV ≈ −21 systems: GLASS-z12 and GLASS-z10. These galaxies display abrupt ≳1.8 mag breaks in their spectral energy distributions (SEDs), consistent with complete absorption of flux bluewards of Lyα that is redshifted to =+z12.40.3 0.1and=+z10.40.5 0.4. Lower redshift interlopers such as quiescent galaxies with strong Balmer breaks would be comfortably detected at >5σ in multiple bands where instead we find no flux. From SED modeling we infer that these galaxies have already built up ∼109 solar masses in stars over the ≲300–400 Myr after the Big Bang. The brightness of these sources enable morphological constraints. Tantalizingly, GLASS-z10 shows a clearly extended exponential light profile, potentially consistent with a disk galaxy of r50 ≈ 0.7 kpc. These sources, if confirmed, join GN-z11 in defying number density forecasts for luminous galaxies based on Schechter UV luminosity functions, which require a survey area >10× larger than we have studied here to find such luminous sources at such high redshifts. They extend evidence from lower redshifts for little or no evolution in the bright end of the UV luminosity function into the cosmic dawn epoch, with implications for just how early these galaxies began forming. This, in turn, suggests that future deep JWST observations may identify relatively bright galaxies to much earlier epochs than might have been anticipated., R.P.N. acknowledges funding from JWST programs GO-1933 and GO-2279. Support for this work was provided by NASA through the NASA Hubble Fellowship grant HST-HF2-51515.001-A awarded by the Space Telescope Science Institute, which is operated by the Association of Universities for Research in Astronomy, Incorporated, under NASA contract NAS5-26555. We acknowledge support from: the Swiss National Science Foundation through project grant 200020_207349 (P.A.O., A.W.). The Cosmic Dawn Center (DAWN) is funded by the Danish National Research Foundation under grant No. 140. R.J.B. and M.S. acknowledge support from NWO grant TOP1.16.057

Supermassive black holes (SMBH, 10^5-10^10 M_odot) have regularly been found at the center of massive galaxies. However, we still know little about their formation mechanism. Extremely luminous active galactic nuclei (AGN), revealing the presence of massive SMBHs, were detected in the high redshift Universe, a few 10^8 years after the Big Bang. A rapid growth mechanism is thus needed, such as a rapid accretion (beyond the Eddington limit) onto intermediate-mass black holes (IMBH, 10^2 - 10^5 M_odot), or the mergers of these black holes. Some of the original IMBHs may have avoided accretion or mergers, and thus still be found in the local Universe, for example as active dwarf galaxies. However, to date, the evidence for these IMBHs remains scarce. Conversely, stellar-mass black holes are found in the Milky Way and nearby galaxies. They are often detected in X-ray binaries (XRB), composed of a compact object - a neutron star or a black hole - accreting from a companion star. Ultraluminous X-ray sources (ULXs) may be a luminous version of the XRBs, and are thought to be powered by super-Eddingtonaccretion above the Eddington limit onto stellar-mass compact objects, but the most often the exact mechanism and the nature of the accretor are largely unknown. A few hyperluminous X-ray sources (HLXs, defined as ULXs with L_X> 10^{41} erg/s), may be good candidates for IMBHs. X-ray emission is a well-known signature of accreting systems, and thus X-ray surveys are the ideal place to search for new accreting black holes. The modern X-ray observatories Swift, XMM-Newton and Chandra have detected about a million point-like sources which are yet to be identified. With these and upcoming telescopes, an automated classification of X-ray sources becomes increasingly valuable. Using this approach could provide the cleanest samples possible, where currently contaminants limit population studies of ULXs, HLXs and active dwarf galaxy candidates. In this thesis I develop an automated and probabilistic classification of X-ray sources. The Swift-XRT, XMM-Newton and Chandra catalogues are cross-correlated with each othern with optical and infrared catalogues and with the highly complete census of galaxies GLADE. From these spatial, spectral, photometrical and timing properties, the classification identifies, amongst others, populations of AGN, stars and XRBs, and can be optimised to focus on one class. It efficiently retrieves AGN and stars, but other classes have small training samples limiting the classification performance. A citizen science experiment (CLAXSON) is proposed to enlarge these samples. The classification is then applied to X-ray sources overlapping GLADE galaxies. 1901 ULX candidates are accurately identified, where analysis indicates that it is the cleanest large sample in the current literature. Their spatial distribution, hardness, variability and rates in different environments are studied. I analyse their X-ray luminosity function and confirm the presence of a powerlaw break at a luminosity of 10^40 erg/s for spiral galaxies, tentatively proposed in previous studies. HLX candidates are inspected and cross-correlated with optical sources with redshift to remove possible contaminants. The resulting 191 HLX candidates are statistically compared to ULXs, showing tentative differences perhaps due to a different accretor mass range. Likewise, 91 active dwarf galaxy candidates are identified, where half of them appear to have an off-centre nucleus. I analyse the active fraction of dwarf galaxies in different bins of galaxy mass and limiting luminosity, and I estimate the intrinsic fraction harbouring a black hole. Assuming that these AGN and HLX candidates are indeed black holes, their black hole mass distribution suggests a large fraction of IMBHs. I analyse how this mass compares with galaxy mass. Differences are observed between the two types of candidates and interpreted in terms of IMBH formation mechanisms.; Les trous noirs supermassifs (TNS, 10^5-10^10 M_odot) sont observés au centre de nombreuses galaxies massives. Pourtant, leur mécanisme de formation reste incertain. Une croissance rapide est nécessaire pour expliquer certains noyaux actifs de galaxies (AGN) vus à haut redshift, comme une accrétion rapide (au-delà de la limite d'Eddington) sur des trous noirs de masse intermédiaire (TNI, 10^2-10^5 M_odot), ou la fusion de ces trous noirs. Une partie de ces TNI pourrait avoir eu une faible croissance et se retrouver encore dans l'Univers local, par exemple sous forme de galaxies naines actives. Cependant, à ce jour, les preuves de l'existence de ces TNIs restent rares. À l'inverse, les trous noirs de masse stellaire sont présents dans la Voie lactée et les galaxies proches. Ils sont souvent détectés dans des binaires X (XRB), composées d'un objet compact - étoile à neutrons ou trou noir - qui accrète d'une étoile compagnon. Les sources X ultralumineuses (ULX), qui sont peut-être une version lumineuse des XRBs, seraient alimentées par l'accrétion super-Eddington sur des objets compacts de masse stellaire, mais le plus souvent sa nature et le mécanisme exact sont inconnus. Certaines sources X hyperlumineuse (HLX, défini comme un ULX ayant L_X>10^41 erg/s) pourraient être des bons candidats pour des TNIs. L'émission de rayons X étant une signature importante des systèmes accrétants, les relevés en rayons X sont l'endroit idéal pour trouver de nouveaux trous noirs. Les observatoires modernes en rayons X Swift, XMM-Newton et Chandra ont détecté environ un million de sources ponctuelles qui n'ont pas encore été identifiées. Avec ces télescopes et ceux à venir, une classification automatisée des sources de rayons X devient indispensable. Elle pourrait notamment réduire la part de contaminants qui sont souvent un frein dans l'étude des échantillons d'ULXs, HLXs et galaxies naines actives. Dans cette thèse, je développe une classification automatisée et probabiliste des sources de rayons X. Les catalogues Swift-XRT, XMM-Newton et Chandra sont corrélés entre eux et avec des catalogues optiques et infrarouges, ainsi que le recensement complet de galaxies GLADE. A partir de ces propriétés spatiales, spectrales, photométriques et temporelles, la classification identifie entre autres des populations d'AGN, d'étoiles et de XRBs, et peut être optimisée pour une classe d'intérêt. Les AGN et les étoiles sont classifiés avec précision, mais les autres classes ont de petits échantillons d'entraînement limitant la classification. Une expérience de science participative (CLAXSON) est proposée pour les augmenter. La classification est ensuite appliquée aux sources recouvrant les galaxies GLADE. 1901 candidats ULX sont identifiés, probablement l'échantillon le plus grand et propre de la littérature actuelle. Leurs distributions spatiale, spectrale et dans différents environnements sont étudiées. J'analyse leur fonction de luminosité et confirme la présence d'une cassure de la loi de puissance à L_X~10^40 erg/s pour les galaxies spirales. Les candidats HLX sont inspectés et de nombreux contaminants éliminés grâce à leur redshift. Les 191 candidats HLX restants sont comparés aux ULXs, montrant de légères différences peut-être dues à une gamme de masse d'accréteur différente. J'obtiens enfin 91 candidats galaxies naines actives. J'analyse la fraction active des galaxies dans différents intervalles de masse de galaxie et de luminosité limite, puis j'estime la fraction intrinsèque abritant un trou noir. En supposant que ces candidats AGN et HLX sont effectivement des trous noirs, leur distribution de masse de trou noir révèle une grande fraction de TNIs. J'analyse comment cette masse se compare à la masse de la galaxie. Des différences sont observées entre ces deux types de candidats et interprétées en termes de mécanismes de formation des TNIs.

We conduct a systematic search for protocluster candidates at $z \geq 6$ in the COSMOS field using the recently released COSMOS2020 source catalog. We select galaxies using a number of selection criteria to obtain a sample of galaxies that have a high probability of being inside a given redshift bin. We then apply overdensity analysis to the bins using two density estimators, a Weighted Adaptive Kernel Estimator and a Weighted Voronoi Tessellation Estimator. We have found 15 significant ($>4\sigma$) candidate galaxy overdensities across the redshift range $6\le z\le7.7$. The majority of the galaxies appear to be on the galaxy main sequence at their respective epochs. We use multiple stellar-mass-to-halo-mass conversion methods to obtain a range of dark matter halo mass estimates for the overdensities in the range of $\sim10^{11-13}\,M_{\rm \odot}$, at the respective redshifts of the overdensities. The number and the masses of the halos associated with our protocluster candidates are consistent with what is expected from the area of a COSMOS-like survey in a standard $\Lambda$CDM cosmology. Through comparison with simulation, we expect that all the overdensities at $z\simeq6$ will evolve into a Virgo-/Coma-like clusters at present (i.e., with masses $\sim 10^{14}-10^{15}\,M_{\rm \odot}$). Compared to other overdensities identified at $z \geq 6$ via narrow-band selection techniques, the overdensities presented appear to have $\sim10\times$ higher stellar masses and star-formation rates. We compare the evolution in the total star-formation rate and stellar mass content of the protocluster candidates across the redshift range $6\le z\le7.7$ and find agreement with the total average star-formation rate from simulations., Comment: 52 pages, 32 figues, 18 tables, main text is 30 pages, appendix is 22 pages, to be published in ApJ

Understanding the physical processes responsible for ceasing, or ‘quenching’, star formation in galaxies is one of the most important unsolved questions in the field of galaxy evolution. Over the past two decades multiple mechanisms were suggested as potential drivers of the transition between the star-forming and quiescent galaxy categories, painting a very complex picture of quenching and its potential physical drivers. In this thesis we take on the challenge of identifying and characterising the physics of galaxy quenching by combining traditional statistical methods with machine learning techniques to embrace the complexity of all physical processes at play. We first show how both gas fraction and star formation efficiency (SFE) decrease in Sloand Digital Sky Survey (SDSS) galaxies at z = 0 as they depart from the star-forming Main Sequence (MS) towards quiescence. We further show that both quantities correlate similarly strongly with the departure from the MS, implying the need for any physical model of quenching to invoke a change in both gas fraction and SFE. We then move on to extract theoretical predictions of the observable consequences of Active Galactic Nucleus (AGN) feedback quenching from three state-of-the-art cosmological simulations: EAGLE, Illustris and IllustrisTNG. Our machine learning (ML) classification reveals supermassive black hole mass (MBH) as the most predictive parameter in determining whether a galaxy is star forming or quenched at redshift z = 0 in all three simulations. This prediction is met overwhelmingly well in the observations, where it is true for a range of indirect estimates of MBH via proxies as well as its dynamical measurements. In simulations we further demonstrate that it is the integrated power output of the AGN, rather than its instantaneous activity, which causes galaxies to quench. We thus mark our most important contribution to the field by providing direct evidence in favour of the AGN quenching paradigm, together with suggestions on how to best observe the effect supermassive black holes have on their galactic hosts. Finally, we analyse the trends in molecular gas content with MBH, finding that the SDSS observations more closely follow trends predicted by IllustrisTNG, rather than the Illustris suite. In our current ongoing work we also analyse spatially resolved properties of the cold ISM, rigorously testing the ability of current cosmological simulations to successfully recover realistic ISM on kpc scales. As a result of our study we further conclude that a viable AGN feedback prescription can be achieved by a combination of preventative feedback and turbulence injection which together quench star formation in central galaxies., MERAC Foundation

In the present work, the galaxy luminosity function (LF) has been studied for a sample of seven clusters in the redshift range (0.0 ≲ z ≲ 0.1), within Abell radius (1.5 h−1 Mpc), in the five SDSS passbands ugriz. In each case, the absolute magnitude distribution is found and then fitted with a Schechter function. The fitting is done, using the χ2 – minimization method to find the best values of Schechter parameters Ф* (normalization constant), M* (characteristic absolute magnitude), and α (faint-end slope). No remarkable changes are found in the values of M* and α, for any cluster, in any passband. Furthermore, the LF does not seem to vary with such cluster parameters as richness, velocity dispersion, and Bautz–Morgan morphology. Finally, it is found that M* becomes brighter toward redder bands, whereas almost no variation is seen in the value of α with passband, being around (−1.00).

Observations and simulations of interacting galaxies and mergers in the local universe have shown that interactions can significantly enhance the star formation rates (SFR) and fueling of Active Galactic Nuclei (AGN). However, at higher redshift, some simulations suggest that the level of star formation enhancement induced by interactions is lower due to the higher gas fractions and already increased SFRs in these galaxies. To test this, we measure the SFR enhancement in a total of 2351 (1327) massive ($M_*>10^{10}M_\odot$) major ($1, Comment: 23 pages, 13 figures, Accepted for publication in ApJ

Galaxies in the local Universe fall into two main categories of spirals and ellipticals. In this Thesis, we explore the structural evolution of galaxies into this bimodal distribution. To do so, we study galaxies in the context of the Fundamental Plane, the tight scaling relation between galaxy size, kinematics and luminosity, which connects the structural and stellar population properties of galaxies. This work is built on a combination of observational data and theoretical models. Large spectroscopic surveys are used to construct a representative sample of massive quiescent and star-forming galaxies across 8 Gyr of cosmic time. We hence show that there is strong variation and evolution in the mass-to-light ratios of galaxies, due to evolution in the stellar populations. However, surprisingly, all galaxies lie on a single mass Fundamental Plane, which does not evolve with time. Cosmological simulations are used to assess the structural properties that may underlie the observed mass Fundamental Plane. Based on the simulations, we propose that this relation may originate from a systematic variation in the central dark matter content within galaxies as a function of their size and mass.

In the last years, we have obtained and analysed a collection of deep optical spectra of a large number of HII regions in the Milky Way,MagellanicClouds and other nearby galaxies, taken with VLT and GTC telescopes. These data have permitted to determine the spatial abundance distribution of several elements with unprecedented precision. An important result of this study is the estimation ofmetallicityvariations throughout the discs of the galaxies in order to know the degree of homogeneity and mixing in the ionized gas phase of the interstellar medium (ISM). From our data, we find that the amplitude of such variations are of the order of the errors of abundance determinations of individual objects, indicating the absence of largeinhomogeneitiesalong the whole disc in the case of theMagellanicClouds and at a givengalactocentricdistance, in the case of the Milky way and other spiral galaxies. Our results for the Milky Way contrast withrecentmetallicityestimations in neutral clouds of the local Galactic thin disk that foundmetallicityvariations of the order of a factor ten. We compare the results obtained for neutral clouds with those for HII regions and other tracers of the chemical composition of the ISM as B-type stars, classicalCepheidsand young clusters.

We study the $r$-band luminosity function (LF) faint end of galaxies in clusters and their environment, its mass dependence and evolution over cosmic time up to $z=2.8$. We post-processed data from the C-EAGLE simulation project, formed by 30 high-resolution simulations of galaxy clusters, computing galaxy luminosities in different bands from UV to IR, using the E-MILES stellar spectra library. The C-EAGLE numerical resolution allows us to study galaxies with a $\log(M_star)>8.2$. The (stacked) LFs inside $r_{200}$ are already well defined at z=2.8, with a well populated faint end. Overall, the LFs faint-end shows relatively little time evolution and only a modest dependence on the cluster mass. The clusters cores are rich in dwarf galaxies at all times, with their LF's faint-end constantly steeper than $\alpha=-1.28\pm 0.04$, although it does not reach the halo mass function slope. Remarkably, all the clusters develop a faint-end upturn at $z\lesssim 0.35$, best modelled with a double Schechter function, with the clusters having $\log (M_{200}/\Msun)

The examination of the spatially resolved IFS maps in a sample of more than 500 lenticular (S0) galaxies drawn from the MaNGA survey has unveiled the existence of transient inner annular structures (〈R〉 ∼ 1 Re) betraying ongoing star formation in a good number of these objects. Activity gradients in these galaxies have been measured through a novel methodology based on the principal component analysis of their optical spectra averaged over bins of galactocentric radius. We find that the sign of these gradients is closely linked to the presence of rings in the spectral maps, which are specially conspicuous in the equivalent width of Hα-emission, EW(Hα), with a fractional abundance —22–37% depending on the strictness of ring identification— larger than that inferred from optical imaging. While the numbers of S0s with globally positive, negative, and flat activity gradients are comparable, star-forming rings are found almost exclusively in objects with a positive slope for which quenching proceeds inside-out, in good agreement with predictions from cosmological simulations studying S0 buildup. The assessment of these structures and the properties of the galaxies harboring them also indicates that the frequency of such rings increases with the mass of their hosts, that they feed mainly on the gas from the disks, that are more short-lived in galaxies with ongoing star formation, and that the local environment does not play a relevant role in their formation. From the present analysis, we conclude that the presence of rings in the EW of the Hα emission line is a common phenomenon among fully formed S0s, possibly associated with annular disk resonances driven by weakly disruptive mergers preferentially involving the more massive representatives of these galaxies and their smaller and closer satellites., We acknowledge financial support from the Spanish state agency MCIN/AEI/10.13039/501100011033 and by 'ERDF A way of making Europe' funds through research grants PID2019–106027GB–C41 and PID2019–106027GB–C43. MCIN/AEI/10.13039/501100011033758 has also provided additional support through the Centre of Excellence Severo Ochoa's award for the Instituto de Astrofísica de Andalucía under contract SEV–2017–0709 and the Centre of Excellence María de Maeztu's award for the Institut de Ciències del Cosmos at the Universitat de Barcelona under contract CEX2019–000918–M. J.L.T. acknowledges support by the PRE2020–091838 grant from MCIN/AEI/10.13039/501100011033766 and by 'FSE Invests in your future'. H.D.S. acknowledges support by the PID2020-115098RJ-I00 grant from MCIN/AEI/10.13039/501100011033., {"references":["Deeley, S., Drinkwater, M. J., Sweet, S. M., et al. 2021, MNRAS, 508, 895, 2021MNRAS.508..895D","Jiménez-Palau, C., Solanes, J. M., Perea, J. D., del Olmo A., & Tous, J. L. 2022, MNRAS, 515, 3956, 2022MNRAS.515.3956J","Mapelli, M., Rampazzo, R., & Marino, A. 2015, A&A, 575, A16, 2015A&A...575A..16M","Tous, J. L., Solanes, J. M., & Perea, J. D. 2020, MNRAS, 495, 4135, 2020MNRAS.495.4135T"]}

Cluster galaxies are subject to a whole range of processes and interactions that dramatically change their properties. To shed light on these issues, we analyze the most homogeneous and complete local cluster galaxy survey to date: WINGS/OmegaWINGS, and use stellar population synthesis techniques to obtain properties such as stellar mass, stellar ages, SFR, and SFH. Our results show that, although the cluster environment eventually shuts off the star formation, some mechanisms might instead enhance it temporarily, i.e., ram pressure and close encounters with other galaxies. In this picture, it is crucial to take morphology into account: while cluster spirals do follow the main sequence, early types still display some level of star formation, likely triggered by hydrodynamic interactions with other galaxies. Finally, the local environment dominates the stellar evolution, while the global cluster is likely a secondary agent.

In order to explain the lack of star formation of the galaxy stellar mass function in the low and more massive range, the common theoretical model is due to two feedback proccesses depending to the mass range. In one hand, supernovae is putting energy in low mass galaxies, expelling the gas away from the center of the galaxy and reducing that way the amount of cooling and, thus, the amount of star formation. On the other hand, when you go to more massive galaxies, the supernovae is not efficient enough to reduce the star formation and thus you need the effect of BH feedback to quenched this galaxies. In the last few years, several observational studies, as Mezcua+18, have found some population of dwarf galaxies in which AGN feedback may also play an importan role. To better understand how AGN could affect dwarf galaxies, I used a set of 12 dwarf galaxies run with the AURIGA galaxy formation model. Each galaxy was run with and without BH to isolate the effects of the AGN feedback. If we go back to the stellar-to-halo-mass relation and look at the point (each color representing one of the galaxies of my set) the dot represent the configuration run with black hole while the cross point represent the configuration without. You can see how, the configuration without BH tends to have more stellar mass that their counterparts. That's means AGN feedback could be shutting down star formation. If we now take a look into the star formation history of each galaxy (dark line is shown the mass of the BH through the time), galaxies with a larger black hole also have an huge gap in the star formation history between these two configurations, where the one without BH have more star formation. For the galaxy with the largest BH, if we increase the resolution, the gap is even more noticeable. Also, we can see the effect of the BH by looking into the brightness and dark matter profiles. The inner part of the galaxy are less bright and also less dense for the one with AGN feedback. Finally, we can also check the kinematic properties by making a 2D maps velocity. AGN have an impact into the rotation, making the galaxy slower that its counterpart, and also less dense., {"references":["Mezcua et al. (2018). Decouple software associated to arXiv:2110.08629","Latimer et al. (2021). Decouple software associated to arXiv:2111.10388","Davis et al. (2022). Decouple software associated to arXiv:2201.09903","Benson et al. (2003). Decouple software associated to arXiv:astro-ph/0302450","Koudmani et al. (2021). Decouple software associated to arXiv:2007.10342","Sharma et al. (2021). Decouple software associated to arXiv:1912.06646","Grand et al. (2017). Decouple software associated to arXiv:1610.01159","Waterval et al. (2022). Decouple software associated to arXiv:2204.13373"]}

Class material, including final presentations, for the 2018/2019 Science Research Mentoring Program (SRMP), held at the Harvard-Smithsonian Center for Astrophysics

We use the Illustris-1 simulation to explore the capabilities of Hubble and James Webb Space Telescope data to analyze the stellar populations in high-z galaxies, taking advantage of the combined depth, spatial resolution, and wavelength coverage. For that purpose, we use simulated broad-band ACS, WFC3 and NIRCam data and 2-dimensional stellar population synthesis (2D-SPS) to derive the integrated star formation history (SFH) of massive (M∗ > 1010 M☉) simulated galaxies at 1 < z < 4 that evolve into a local M∗> 1011 M☉ galaxy. We explore the potential of HST and JWST datasets reaching a depth similar to those of the CANDELS and ongoing CEERS observations, respectively, and concentrate on determining the capabilities of this dataset for characterizing the first episodes in the SFH of local M∗ > 1011 M☉ galaxies by studying their progenitors at z > 1. The 2D-SPS method presented in this work has been calibrated to robustly recover the cosmic times when the first star formation episodes occurred in massive galaxies, i.e., the first stages in their integrated SFHs. In particular, we discuss the times when the first 1% to 50% of their total stellar mass formed in the simulation. We demonstrate that we can recover these ages with typical median systematic offset of

We present a study of the orbits, environments and morphologies of 13 ram-pressure stripped galaxies in the massive, intermediate redshift (z$\sim0.3-0.4$) galaxy clusters A2744 and A370, using MUSE integral-field spectroscopy and HST imaging from the Frontier Fields Program. We compare different measures of the locations and morphologies of the stripped sample with a sample of 6 poststarburst galaxies identified within the same clusters, as well as the general cluster population. We calculate the phase space locations of all cluster galaxies and carry out a substructure analysis, finding that the ram-pressure stripped galaxies in A370 are not associated with any substructures, but are likely isolated infalling galaxies. In contrast, the ram-pressure stripped galaxies in A2744 are strictly located within a high-velocity substructure, moving through a region of dense X-ray emitting gas. We conclude that their ram-pressure interactions are likely to be the direct result of the merger between two components of the cluster. Finally, we study the morphologies of the stripped and poststarburst galaxies, using numerical measures to quantify the level of visual disturbances. We explore any morphological deviations of these galaxies from the cluster population, particularly the weaker cases which have been confirmed via the presence of ionised gas tails to be undergoing ram-pressure stripping, but are not strongly visually disturbed in the broad-band data. We find that the stripped sample galaxies are generally divergent from the general cluster sample, with poststarburst galaxies being intermediary in morphology between stripped galaxies and red passive cluster members., 27 pages, 17 figures

We present the first measurements of HI galaxy scaling relations from a blind survey at $z>0.15$. We perform spectral stacking of 9023 spectra of star-forming galaxies undetected in HI at $0.23, Comment: 12 pages, 5 figures. Accepted for publication in ApJ Letters on 30 July 2022

The neutral atomic gas content of individual galaxies at large cosmological distances has until recently been difficult to measure due to the weakness of the hyperfine H i 21 cm transition. Here we estimate the H i gas mass of a sample of main-sequence star-forming galaxies at z ∼ 6.5–7.8 surveyed for [C ii] 158 μm emission as part of the Reionization Era Bright Emission Line Survey (REBELS), using a recent calibration of the [C ii]-to-H i conversion factor. We find that the H i gas mass excess in galaxies increases as a function of redshift, with an average of M Hi /M ⋆ ≈ 10, corresponding to H i gas mass fractions of f Hi = M Hi /(M ⋆ + M Hi ) = 90%, at z ≈ 7. Based on the [C ii] 158 μm luminosity function (LF) derived from the same sample of galaxies, we further place constraints on the cosmic H i gas mass density in galaxies (ρ Hi ) at this redshift, which we measure to be ρ H I = 7.1 − 3.0 + 6.4 × 10 6 M ⊙ Mpc − 3 . This estimate is substantially lower by a factor of ≈10 than that inferred from an extrapolation of damped Lyα absorber (DLA) measurements and largely depends on the exact [C ii] LF adopted. However, we find this decrease in ρ Hi to be consistent with recent simulations and argue that this apparent discrepancy is likely a consequence of the DLA sight lines predominantly probing the substantial fraction of H i gas in high-z galactic halos, whereas [C ii] traces the H i in the ISM associated with star formation. We make predictions for this buildup of neutral gas in galaxies as a function of redshift, showing that at z ≳ 5, only ≈10% of the cosmic H i gas content is confined in galaxies and associated with the star-forming ISM.

As one of the most extreme environments in the universe, galaxy clusters prove to be important probes of cosmology and galaxy evolution. In the local universe, galaxy populations in clusters are known to differ from the isolated/ field galaxy population in their average morphology, star formation rates, metallicities, spin, stellar mass function etc. Although the effect of environment in the local universe is well explored, how and when the evolution of cluster galaxy populations begin to diverge is not well understood. In this thesis, we explore the role of environment in the evolution of inter-stellar medium properties and star formation in the epoch when galaxy clusters are in their nascent stages. We study two protoclusters at z ∼ 2 from the ZFIRE spectroscopic and ZFOURGE photometric surveys and use IllutrisTNG cosmological simulations to understand the onset of the effect of environment on galaxy evolution in cosmic noon. First, we probe the interstellar medium of galaxies in a z = 1.62 proto-cluster with higher star formation density, considerable molecular gas fraction and tentatively low ionisation parameter (compared to the field galaxies). We measure the global electron density using the [OII] (λ3726,λ3729) doublet ratio in spectroscopic data from the Keck observatory. Contrary to the measurements at lower redshift, we find a tentative enhancement of the median electron density by a factor of three in galaxies in the UDS proto-cluster environment compared to the field galaxies at comparable redshifts, stellar mass and star formation rates. This indicates an effect of environment on the star formation history and the gas content of the galaxies. We also find that the electron density increases with redshift in both cluster and field environments from z = 0 to z ∼ 2 by a factor of 10. Next, we measure the star formation histories of galaxies in a proto-cluster at z = 2 using the Spectral Energy Distribution fitting module Prospector. Comparable to previous studies, we show that massive galaxies have a consistent/declining star formation history compared to the low mass galaxies that have rising star formation histories. We also find that the most massive protocluster galaxies (log M∗/M⊙ > 10.5) from the ZFIRE sample are starting to show signs of star formation suppression as early as z = 2. The massive protocluster galaxies form 45 ± 8% of their total stellar mass in the first 2 Gyr of the universe compared to 31 ± 2% formed in the field galaxies. We compare our observational results with IllustrisTNG cosmological simulations and find similar star formation histories. Using IllustrisTNG, we further probe the physical mechanisms driving the star formation history and find that the progenitors of cluster galaxies consistently have lower gas fraction in their stellar disk compared to the progenitors of the field galaxies since z ∼ 5, leading to the suppression of star formation observed at z ∼ 2. Finally, to understand the cause of lower gas fractions in the cluster galaxies, we explore the role of environment in the accretion of gas in the early universe. We track the history of total gas accretion in satellite and central galaxies in cluster and field halos and find that the central galaxies continue to accrete gas, however the satellite galaxies in large halos (log Mhalo/M⊙ > 13) stop accreting gas effectively after the infall into their host halo by z = 2. We find that the gas inflow rates of centrals are positively correlated with the halo mass of their host halo across z = 6 to 2. Whereas, after the final infall, the gas inflow rates for satellite galaxies in large halos are negatively correlated with the halocentric distance and the local overdensity. These results indicate that well before the effect of environment due to gravitational and hydrodynamical processes acting on cluster galaxies becomes significant, the position of galaxies in the cosmic web in the early universe started to affect their evolution, setting stage for the eventual divergence of evolution of cluster galaxies as observed in the local universe.

We present spatially-resolved morphological properties of [CII] 158 $\mu$m, [OIII] 88 $\mu$m, dust, and rest-frame ultraviolet (UV) continuum emission for A1689-zD1, a strongly lensed, sub-L* galaxy at $z=7.13$, by utilizing deep Atacama Large Millimeter/submillimeter Array (ALMA) and Hubble Space Telescope (HST) observations. While the [OIII] line and UV continuum are compact, the [CII] line is extended up to a radius of $r \sim 12$ kpc. Using multi-band rest-frame far-infrared (FIR) continuum data ranging from 52-400 $\mu$m, we find an average dust temperature and emissivity index of $T_{\rm dust} = 41^{+17}_{-14}$ K and $\beta = 1.7^{+1.1}_{-0.7}$, respectively, across the galaxy. We find slight differences in the dust continuum profiles at different wavelengths, which may indicate that the dust temperature decreases with distance. We map the star-formation rate (SFR) via IR and UV luminosities and determine a total SFR of $37\pm 1~M_\odot~{\rm yr}^{-1}$ with an obscured fraction of $87\%$. While the [OIII] line is a good tracer of the SFR, the [CII] line shows deviation from the local $L_{\rm [CII]}$-SFR relations in the outskirts of the galaxy. Finally, we observe a clear difference in the line profile between [CII] and [OIII], with significant residuals ($\sim 5\sigma$) in the [OIII] line spectrum after subtracting a single Gaussian model. This suggests a possible origin of the extended [CII] structure from the cooling of hot ionized outflows. The extended [CII] and high-velocity [OIII] emission may both contribute in part to the high $L_{\rm [OIII]}$/$L_{\rm [CII]}$ ratios recently reported in $z>6$ galaxies., Comment: 22 pages, 14 figures, accepted to ApJ, presented at AAS240

We present the first results on the spatial distribution of dust attenuation at $1.0, Comment: 7 pages, 5 figures, submitted to ApJL

We present the results of a systematic search for candidate quiescent galaxies in the distant Universe in eleven $JWST$ fields with publicly available observations collected during the first three months of operations and covering an effective sky area of $\sim145$ arcmin$^2$. We homogeneously reduce the new $JWST$ data and combine them with existing observations from the $Hubble\,Space\,Telescope$. We select a robust sample of $\sim80$ candidate quiescent and quenching galaxies at $3 < z < 5$ using two methods: (1) based on their rest-frame $UVJ$ colors, and (2) a novel quantitative approach based on Gaussian Mixture Modeling of the $NUV-U$, $U-V$, and $V-J$ rest-frame color space, which is more sensitive to recently quenched objects. We measure comoving number densities of massive ($M_\star\geq 10^{10.6} M_\odot$) quiescent galaxies consistent with previous estimates relying on ground-based observations, after homogenizing the results in the literature with our mass and redshift intervals. However, we find significant field-to-field variations of the number densities up to a factor of $2-3$, highlighting the effect of cosmic variance and suggesting the presence of overdensities of red quiescent galaxies at $z>3$, as it could be expected for highly clustered massive systems. Importantly, $JWST$ enables the robust identification of quenching/quiescent galaxy candidates at lower masses and higher redshifts than before, challenging standard formation scenarios. All data products, including the literature compilation, are made publicly available., Comment: 15 pages, 6 Figures + Appendix. Accepted for publication in ApJ on Feb, 9. Data release: - Reduced HST+JWST mosaics + photometric catalogs and Eazy-py modeling: https://erda.ku.dk/archives/7166d013c1ca1371aac3c57b9e73190d/published-archive.html - Supplementary material and tables: https://zenodo.org/record/7614908#.Y-4ZruzMLmE - MAST: https://doi.org/10.17909/g3nt-a370 - See also Gould et al. 2023

We present a new approach to observationally constrain where the tails of Jellyfish (JF) galaxies in groups and clusters first appear and how long they remain visible with respect to the moment of their orbital pericenter. This is accomplished by measuring the distribution of their tail directions with respect to their host's center, and their distribution in a projected velocity-radius phase-diagram. We then model these observed distributions using a fast and flexible approach where JF tails are painted onto dark matter halos according to a simple parameterised prescription, and perform a Bayesian analysis to estimate the parameters. We demonstrate the effectiveness of our approach using observational mocks, and then apply it to a known observational sample of 106 JF galaxies with radio continuum tails located inside 68 hosts such as groups and clusters. We find that, typically, the radio continuum tails become visible on first infall when the galaxy reaches roughly three quarters of r$_{200}$, and the tails remain visible for a few hundred Myr after pericenter passage. Lower mass galaxies in more massive hosts tend to form visible tails further out and their tails disappear more quickly after pericenter. We argue that this indicates they are more sensitive to ram pressure stripping. With upcoming large area surveys of JF galaxies in progress, this is a promising new method to constrain the environmental conditions in which visible JF tails exist., Accepted to ApJ June 2022, 24 pages, 13 figures, 2 tables

In this VERTICO early science paper we explore in detail how environmental mechanisms, identified in H i, affect the resolved properties of molecular gas reservoirs in cluster galaxies. The molecular gas is probed using ALMA ACA (+TP) observations of 12CO(2–1) in 51 spiral galaxies in the Virgo cluster (of which 49 are detected), all of which are included in the VIVA H i survey. The sample spans a stellar mass range of 9 ≤ log M ⋆ / M ⊙ ≤ 11 . We study molecular gas radial profiles, isodensity radii, and surface densities as a function of galaxy H i deficiency and morphology. There is a weak correlation between global H i and H2 deficiencies, and resolved properties of molecular gas correlate with H i deficiency: galaxies that have large H i deficiencies have relatively steep and truncated molecular gas radial profiles, which is due to the removal of low-surface-density molecular gas on the outskirts. Therefore, while the environmental mechanisms observed in H i also affect molecular gas reservoirs, there is only a moderate reduction of the total amount of molecular gas.

We present an ALMA-Herschel joint analysis of sources detected by the ALMA Lensing Cluster Survey (ALCS) at 1.15 mm. Herschel/PACS and SPIRE data at 100-500 $μ$m are deblended for 180 ALMA sources in 33 lensing cluster fields that are either detected securely (141 sources; in our main sample) or tentatively at S/N$\geq$4 with cross-matched HST/Spitzer counterparts, down to a delensed 1.15-mm flux density of $\sim0.02$ mJy. We performed far-infrared spectral energy distribution modeling and derived the physical properties of dusty star formation for 125 sources (109 independently) that are detected at $>2σ$ in at least one Herschel band. 27 secure ALCS sources are not detected in any Herschel bands, including 17 optical/near-IR-dark sources that likely reside at $z=4.2\pm1.2$. The 16-50-84 percentiles of the redshift distribution are 1.15-2.08-3.59 for ALCS sources in the main sample, suggesting an increasing fraction of $z\simeq1-2$ galaxies among fainter millimeter sources ($f_{1150}\sim 0.1$ mJy). With a median lensing magnification factor of $μ= 2.6_{-0.8}^{+2.6}$, ALCS sources in the main sample exhibit a median intrinsic star-formation rate of $94_{-54}^{+84}\,\mathrm{M}_\odot\,\mathrm{yr}^{-1}$, lower than that of conventional submillimeter galaxies at similar redshifts by a factor of $\sim$3. Our study suggests weak or no redshift evolution of dust temperature with $L_\mathrm{IR}10^{12}\,\mathrm{L}_\odot$, the dust temperatures show no evolution across $z \simeq 1 -4$ while being lower than those in the local Universe. For the highest-redshift source in our sample ($z=6.07$), we can rule out an extreme dust temperature ($>$80 K) that was reported for MACS0416 Y1 at $z=8.31$., 44 pages, 23 figures, 4 tables, accepted for publication in ApJ

The 3D-Drift And SHift (3D-DASH) program is a \textit{Hubble Space Telescope} WFC3 F160W imaging and G141 grism survey of the equatorial COSMOS field. 3D-DASH extends the legacy of HST near-infrared imaging and spectroscopy to degree-scale swaths of the sky, enabling the identification and study of distant galaxies ($z>2$) that are rare or in short-lived phases of galaxy evolution at rest-frame optical wavelengths. Furthermore, when combined with existing ACS/F814W imaging, the program facilitates spatially-resolved studies of the stellar populations and dust content of intermediate-redshift ($0.5, Comment: The 3D-DASH mosaic, PSF and cutout generator tool, and the image explorer are available at archive.stsci.edu/hlsp/3d-dash and at www.lamiyamowla.com/3d-dash. Accepted for publication in Astrophysical Journal. arXiv admin note: text overlap with arXiv:1808.04379

Although present-day telescopes provide fabulous images of galaxies up to very high redshift, they have a strong limitation: we can see just the 2D projection on the sky of the galaxy's profile. In this work, we present the evolution of the 3D structure of galaxies out to z=3 by deprojecting Sersic profile fits (Nedkova et al. 2021) to optical+near-IR HST/ACS imaging from CANDELS (Koekemoer et al. 2011; Grogin et al. 2011) and stellar mass estimate inferred via fitting the UV-to-mid-IR spectral energy distribution (Leja et al. 2020). We compare the 2D and 3D evolution of the Mass-size relation with redshift showing that, although the half-light radius is barely affected by the deprojection, the overall galaxy's structure deeply changes. Since central density is thought to play a key role in the star-formation histories of galaxies, our work provides a crucial link with those theoretical models that explain the 'quenching' of galaxies. The main results summarised in this poster are: We publish the 3D light profiles at a common rest-frame wavelength of 5000Å for more than 40000 galaxies in the redshift range 0.5, {"references":["Grogin N.A. et al, 2011, ApJS, 197, 35","Koekemoer A.M. et al., 2011, ApJS, 197, 36","Leja J. et al. 2020, ApJ, 893, 111","Nedkova, K., et al. 2021, MNRAS, 506, 928","van de Ven G., van der Wel A., 2021, ApJ, 914, 45","van der Wel A., et al., 2014, ApJL, 792, L6","Zhang H., et al., 2019, MNRAS, 484, 5170"]}

We analyze spatially resolved and co-added SDSS-IV MaNGA spectra with signal-to-noise ~100 from 2200 passive central galaxies (z~0.05) to understand how central galaxy assembly depends on stellar mass (M*) and halo mass (Mh). We control for systematic errors in Mh by employing a new group catalog from Tinker (2020a,b) and the widely-used Yang et al. (2007) catalog. At fixed M*, the strength of several stellar absorption features varies systematically with Mh. Completely model-free, this is one of the first indications that the stellar populations of centrals with identical M* are affected by the properties of their host halos. To interpret these variations, we applied full spectral fitting with the code alf. At fixed M*, centrals in more massive halos are older, show lower [Fe/H], and have higher [Mg/Fe] with 3.5 sigma confidence. We conclude that halos not only dictate how much M* galaxies assemble, but also modulate their chemical enrichment histories. Turning to our analysis at fixed Mh, high-M* centrals are older, show lower [Fe/H], and have higher [Mg/Fe] for Mh>10^{12}Msun/h with confidence > 4 sigma. While massive passive galaxies are thought to form early and rapidly, our results are among the first to distinguish these trends at fixed Mh. They suggest that high-M* centrals experienced unique early formation histories, either through enhanced collapse and gas fueling, or because their halos were early-forming and highly concentrated, a possible signal of galaxy assembly bias., Accepted for publication in ApJ. 28 pages and 12 figures

The Virgo Environment Traced in CO Survey (VERTICO) is an Atacama Large Millimeter/submillimeter Array Large Program that has observed the influence of environment on molecular gas by mapping the distribution and kinematics of molecular across 51 Virgo Cluster galaxies on sub-kpc scales. In this talk, I will showcase results from first round of VERTICO papers that reveal how physical mechanisms such as ram pressure stripping affect the distribution and star formation efficiency of molecular gas in cluster galaxies in fantastic detail., Presented at CASCA 2022 on May 16, 2022., {"references":["Brown, T., \"VERTICO: The Virgo Environment Traced in CO Survey\", The Astrophysical Journal Supplement Series, vol. 257, no. 2, 2021. doi:10.3847/1538-4365/ac28f5."]}

We characterize the average X-ray and radio properties of quiescent galaxies (QGs) with $\log{(M_\star/M_\odot)}>10$ at $01.5$ is higher than that of star-forming galaxies (SFGs), derived in the same manner as QGs. The stacking analysis of the VLA-COSMOS images is conducted for the identical sample, and the radio signal for QGs is also detected up to $z\sim5$. We find that the radio AGN luminosity of QGs at $z>1.5$ is also higher than SFGs, which is in good agreement with the X-ray analysis. The enhanced AGN activity in QGs suggested by the individual analysis in the X-ray and radio wavelength supports its important role for quenching at high redshift. Their enhanced AGN activity is less obvious at $z, Comment: 24 pages, 20 figures, 2 tables, Accepted for publication in ApJ

A number of theoretical mechanisms have been invoked to explain the transformation of star forming galaxies into quenched galaxies, such as the removal of gas by active galactic nuclei- (AGN) and star formation-driven galactic outflows, and the heating of the galaxy halo and subsequent halting of gas accretion caused by virial shocks and preventative AGN feedback. Nonetheless, we still lack a clear understanding of which mechanism is the most important for quenching galaxies. The goal of this thesis is to study galaxy quenching from an observational perspective and to address the following question: why do galaxies stop forming stars? In the first part of this thesis I examine the relationship between molecular gas (observed with ALMA and NOEMA) and star formation on spatially resolved scales in seven green valley MaNGA galaxies. I find that both the star formation efficiency (SFE) and gas fraction of green valley galaxies is suppressed relative to typical star forming galaxies. These two effects are equally important for suppressing star formation in the outer disc, but it is not possible to rank their effect towards the strongly quenched galaxy centre, where SFE is only constrained to an upper limit. I also show that the significant reduction in gas fraction in the central regions is driven by an increase in stellar mass surface density rather than a decrease in molecular gas surface density, which disfavours quenching mechanisms that eject gas from galaxies. In the second part of this thesis I develop a 2D inclined rotating disc model to estimate the kinematic properties of 1862 MaNGA galaxies, and I use a random forest analysis to explore the relationship between galaxy kinematics and quenching. I find that the average velocity dispersion is overwhelmingly the most important kinematic parameter for predicting galaxy quenching. Furthermore, a full and partial correlation analysis shows that many commonly discussed correlations between galaxy properties (such as stellar mass) and quenching are spurious, and indeed at fixed velocity dispersion these correlations are almost entirely removed. I interpret this finding in the context of the BH-�� relation and argue for a scenario in which quenching occurs due to preventative feedback from AGN. In the third part of this thesis I attempt to directly probe preventative feedback from AGN by analysing a deep ALMA band 4 observation of HE0515-4414 to search for the Sunyaev-Zel'dovich (SZ) signal tracing the quasar's hot halo gas. I find marginal evidence (~3.3��) of large scale (~300 kpc) heating in the visibility plane, as well as ~3.2�� evidence of localised heating to the south west of the central quasar in the image plane. Furthermore, I use SZ maps from the FABLE simulation to demonstrate that ALMA and the ACA are effective at detecting the SZ signal in band 3, and I discuss the optimal strategy for future observations., ERC Advanced Grant 695671 ���QUENCH���

We present Keck Cosmic Web Imager (KCWI) observations of giant Lya halos surrounding 9 galaxy groups and clusters at 2, Comment: ApJ Letters