We have updated the Munich galaxy formation model, L-Galaxies, to follow the radial distributions of stars and atomic and molecular gas in galaxy discs. We include an H2-based star-formation law, as well as a detailed chemical-enrichment model with explicit mass-dependent delay times for SN-II, SN-Ia and AGB stars. Information about the star formation, feedback and chemical-enrichment histories of discs is stored in 12 concentric rings. The new model retains the success of its predecessor in reproducing the observed evolution of the galaxy population, in particular, stellar mass functions and passive fractions over the redshift range 0<=z<=3 and mass range 8<=log(M_*/Msun)<=12, the black hole-bulge mass relation at z=0, galaxy morphology as a function of stellar mass and the mass-metallicity relations of both stellar and gas components. In addition, its detailed modelling of the radial structure of discs allows qualitatively new comparisons with observation, most notably with the relative sizes and masses of the stellar, atomic and molecular components in discs. Good agreement is found with recent data. Comparison of results obtained for simulations differing in mass resolution by more than two orders of magnitude shows that all important distributions are numerically well converged even for this more detailed model. An examination of metallicity and surface-density gradients in the stars and gas indicates that our new model, with star formation, chemical enrichment and feedback calculated self-consistently on local disc scales, reproduces some but not all of the trends seen in recent many-galaxy IFU surveys.
The fate of metals ejected by young OB associations into the Interstellar Medium (ISM) is investigated numerically. In particular, we study the enrichment of the cold gas phase, which is the material that forms molecular clouds. Following previous work, the expansion and collision of two supershells in a diffuse ISM is simulated, in this case also introducing an advected quantity which represents the metals expelled by the young stars. We adopt the simplest possible approach, not differentiating between metals coming from stellar winds and those coming from supernovae. Even though the hot, dif…
Centre for Space Research, North-West University（西北大学空间研究中心）；National Centre for Radio Astrophysics (NCRA), Tata Institute of Fundamental Research (TIFR)（塔塔基础研究院国家射电天文学中心）；National Institute for Theoretical and Computational Sciences (NITheCS)（理论与计算科学国立研究所）；Dayanand Science College（戴亚南德理学院）
We focus on exploring the metal enrichment of the intergalactic medium (IGM) in Cold and Warm (1.5 and 3 keV) Dark Matter (DM) cosmologies, and the constraints this yields on the DM particle mass, using a semi-analytic model, Delphi, that jointly tracks the Dark Matter and baryonic assembly of galaxies at $z \simeq 4-20$ including both Supernova and (a range of) reionization feedback (models). We find that while ${\rm M_{UV}} \geq -15$ galaxies contribute half of all IGM metals in the Cold Dark Matter model by $z \simeq 4.5$, given the suppression of low-mass halos, larger halos with ${\rm M_{…
We present a detailed analysis of the elemental abundances distribution of the Virgo cluster using {\it XMM-Newton} observations. We included in the analysis a new EPIC-pn energy scale calibration which allow us to measure velocities with uncertainties down to $Δv \sim 150$ km/s. We investigate the radial distribution of O, Ne, Mg, Si, Ar, S, Ca, Ni and Fe. We found that the best-fit model is close to a single-temperature component for distances $>80$~kpc and the cooler gas is more metal-rich. Discontinuities in temperature are found around $\sim30$~kpc and $\sim90$~kpc, which correspond to th…
HYPERION. The cold ISM of rapidly growing $z>6$ quasars: diverse gas reservoirs, dust enrichment, and feedback signatures
INAF - Osservatorio Astronomico di Roma（意大利国家天体物理研究所罗马天文台）；IFPU - Institute for Fundamental Physics of the Universe（宇宙基础物理研究所）；INAF, Osservatorio Astronomico di Trieste（意大利国家天体物理研究所的里雅斯特天文台）；INAF – Osservatorio di Astrofisica e Scienza dello Spazio di Bologna（意大利国家天体物理研究所博洛尼亚空间天体物理学与科学观测站）；Scuola Normale Superiore（比萨高等师范学院）
The surface formation of NH3 and its deuterated isotopologues - NH2D, NHD2, and ND3 - is investigated at low temperatures through the simultaneous addition of hydrogen and deuterium atoms to nitrogen atoms in CO-rich interstellar ice analogues. The formation of all four ammonia isotopologues is only observed up to 15 K, and drops below the detection limit for higher temperatures. Differences between hydrogenation and deuteration yields result in a clear deviation from a statistical distribution in favour of deuterium enriched species. The data analysis suggests that this is due to a higher sti…
Using a high resolution simulation of an isolated dwarf galaxy, accounting for multi-channel stellar feedback and chemical evolution on a star-by-star basis, we investigate how each of 15 metal species are distributed within our multi-phase interstellar medium (ISM) and ejected from our galaxy by galactic winds. For the first time, we demonstrate that the mass fraction probability distribution functions (PDFs) of individual metal species in the ISM are well described by a piecewise log-normal and power-law distribution. The PDF properties vary within each ISM phase. Hot gas is dominated by rec…
We report Atacama Large Millimetre Array (ALMA) observations of four high-redshift dusty star-forming galaxy candidates selected from far-Infrared (FIR)/submm observations in the COSMOS field. We securely detect all galaxies in the continuum and spectroscopically confirm them at z=3.62--5.85 using ALMA 3mm line scans, detecting multiple CO and/or [CI] transitions. This includes the most distant dusty galaxy currently known in the COSMOS field, ID85001929 at z=5.847. These redshifts are lower than we had expected as these galaxies have substantially colder dust temperatures (i.e., their SEDs pe…
Quasars are powerful systems whose spectrum is rich of metal features that allow us to investigate the chemical evolution of galaxies at very high redshift, even close to the reionization epoch. I review the main observational constraints on the metallicity of quasars host galaxies at high redshift and discuss the implications and issues for models of galaxy evolution in the early universe.
The distribution of chemical elements in the hot intracluster medium (ICM) retains valuable information about the enrichment and star formation histories of galaxy clusters, and on the feedback and dynamical processes driving the evolution of the cosmic baryons. In the present study we review the progresses made so far in the modelling of the ICM chemical enrichment in a cosmological context, focusing in particular on cosmological hydrodynamical simulations. We will review the key aspects of embedding chemical evolution models into hydrodynamical simulations, with special attention to the cruc…
We study fundamental properties of steady, spherically symmetric, isothermal galactic outflow in appropriate gravitational potential models. We aim at constructing a universal scale free theory not only for galactic winds, but also for winds from clusters/groups of galaxies. In particular, we consider effects of mass-density distribution on the formation of transonic galactic outflows under several models of the density distribution profile predicted by cosmological simulations of structure formation based on the cold dark matter (CDM) scenario. In this study, we have clarified that there exis…
The reservoir of molecular gas (H$_{\rm 2}$) represents the fuel for the star formation (SF) of a galaxy. Connecting the star formation rate (SFR) to the available H$_{\rm 2}$ is key to accurately model SF in cosmological simulations of galaxy formation. We investigate how modifying the underlying modelling of H$_{\rm 2}$ and the description of stellar feedback in low-metallicity environments (LMF, i.e. low-metallicity stellar feedback) in cosmological, zoomed-in simulations of a Milky Way-size halo influences the formation history of the forming, spiral galaxy and its final properties. We exp…
We used an N-body smoothed particle hydrodynamics algorithm, with a detailed treatment of star formation, supernovae feedback, and chemical enrichment, to perform eight simulations of mergers between gas-rich disc galaxies. We vary the mass ratio of the progenitors, their rotation axes, and their orbital parameters and analyze the kinematic, structural, and chemical properties of the remnants. Six of these simulations result in the formation of a merger remnant with a disc morphology as a result of the large gas-fraction of the remnants. We show that stars formed during the merger (a sudden st…
The emergence of the first sources of light at redshifts of z ~ 10-30 signaled the transition from the simple initial state of the Universe to one of increasing complexity. We review recent progress in our understanding of the formation of the first stars and galaxies, starting with cosmological initial conditions, primordial gas cooling, and subsequent collapse and fragmentation. We emphasize the important open question of how the pristine gas was enriched with heavy chemical elements in the wake of the first supernovae. We conclude by discussing how the chemical abundance patterns conceivabl…
The fate of metals after they are released in starburst episodes is still unclear. What phases of the interstellar medium are involved, in which timescales? Evidence has grown over the past few years that the neutral phase of blue compact dwarf (BCD) galaxies may be metal- deficient as compared to the ionized gas of their HII regions. These results have strong implications for our understanding of the chemical evolution of galaxies. We review here the main results and the main caveats in the abundance determination from far-UV absorption-lines. We also discuss possible scenarios concerning the…
The Square Kilometre Array (SKA) will transform our understanding of the role of the cold, atomic gas in galaxy evolution. The interstellar medium (ISM) is the repository of stellar ejecta and the birthsite of new stars and, hence, a key factor in the evolution of galaxies over cosmic time. Cold, diffuse, atomic clouds are a key component of the ISM, but so far this phase has been difficult to study, because its main tracer, the HI 21 cm line, does not constrain the basic physical information of the gas (e.g., temperature, density) well. The SKA opens up the opportunity to study this component…
Nitrogen-bearing molecules in cold molecular clouds exhibit a range of isotopic fractionation ratios and these molecules may be the precursors of $^{15}$N enrichments found in comets and meteorites. Chemical model calculations indicate that atom-molecular ion and ion-molecule reactions could account for most of the fractionation patterns observed. However, recent quantum-chemical computations demonstrate that several of the key processes are unlikely to occur in dense clouds. Related model calculations of dense cloud chemistry show that the revised $^{15}$N enrichments fail to match observed v…
ALMA Chemical Evolution (ACE) survey: The gas fundamental metallicity relation at cosmic noon
Centro de Astrobiología (CAB), CSIC-INTA（西班牙国家研究委员会-国家航空航天技术研究所 天体生物学中心（CAB））；Leiden University（莱顿大学）；Australian National University（澳大利亚国立大学）；University of Florida（佛罗里达大学）；University of Copenhagen（哥本哈根大学）；Technical University of Denmark（丹麦技术大学）
The abundance of the short-lived radioisotopes 26-Al and 60-Fe in the early Solar system is usually explained by the Sun either forming from pre-enriched material, or the Sun's protosolar disc being polluted by a nearby supernova explosion from a massive star. Both hypotheses suffer from significant drawbacks: the former does not account for the dynamical evolution of star-forming regions, while in the latter the time for massive stars to explode as supernovae can be similar to, or even longer than, the lifetime of protoplanetary discs. In this paper, we extend the disc enrichment scenario to …
Milky Way Mapper decoded abundances -- II: From patterns to paths
Research School of Astronomy and Astrophysics, Australian National University（澳大利亚国立大学天文与天体物理研究学院）；Department of Astronomy, Columbia University（哥伦比亚大学天文学系）；Center for Astrophysics and Space Astronomy, Department of Astrophysical and Planetary Sciences, University of Colorado（科罗拉多大学天体物理学与行星科学系天体物理学与空间天文中心）；Department of Physics & Astronomy, University of Utah（犹他大学物理与天文学系）；Department of Physics and Astronomy, Vanderbilt University（范德堡大学物理与天文学系）；Center for Computational Astrophysics, Flatiron Institute（平顿研究所计算天体物理学中心）；School of Physics and Astronomy, Monash University（莫纳什大学物理与天文学院）；Department of Astronomy, The Ohio State University（俄亥俄州立大学天文学系）；Center for Cosmology and Astroparticle Physics (CCAPP), The Ohio State University（俄亥俄州立大学宇宙学与高能粒子物理中心）
Using a deep (574 ks) Chandra observation of M87, the dominant galaxy of the nearby Virgo Cluster, we present the best measurements to date of the radial distribution of metals in the central intracluster medium (ICM). Our measurements, made in 36 independent annuli with $\sim$250,000 counts each, extend out to a radius r$\sim$40 kpc and show that the abundance profiles of Fe, Si, S, Ar, Ca, Ne, Mg, and Ni are all centrally peaked. Interestingly, the abundance profiles of Si and S - which are measured robustly and to high precision - are even more centrally peaked than Fe, while the Si/S ratio…
Milky Way Mapper decoded abundances -- I. Shared disc enrichment patterns
Australian National University（澳大利亚国立大学）；Columbia University（哥伦比亚大学）；University of Colorado（科罗拉多大学）；University of Utah（犹他大学）；Vanderbilt University（范德堡大学）；Flatiron Institute（平顿研究所）；Monash University（莫纳什大学）；The Ohio State University（俄亥俄州立大学）；New York University（纽约大学）
We show that the factor $\sim$2 discrepancy between spectroscopic and photometric age determinations of the Galactic bulge main-sequence turnoff can be naturally explained by positing an elevated helium enrichment for the bulge relative to that assumed by standard isochrones. We obtain an upper bound on the helium enrichment parameter of the bulge $(ΔY/ΔZ)_{\rm{Bulge}} \lesssim 5.0$ given the requirement that the spectroscopic and photometric ages be consistent and the limiting condition of instantaneous star formation. The corresponding mean age for the bulge is $t_{\rm{Bulge}} \approx 10$ Gy…
We use oxygen and argon abundances for planetary nebulae (PNe) with low internal extinction (progenitor ages of (>4.5 Gyr) and high extinction (progenitor ages <2.5 Gyr), as well as those of the H II regions, to constrain the chemical enrichment and star formation efficiency in the thin and thicker discs of M31. The argon element is produced in larger fraction by Type Ia supernovae (SNe) than oxygen. We find that the mean log(O/Ar) values of PNe as a function of their argon abundances, 12 + log(Ar/H), trace the inter-stellar matter (ISM) conditions at the time of birth of the M 31 disc PN prog…
Lithium abundance in most of the warm metal-poor main sequence stars shows a constant plateau (A(Li)~2.2 dex) and then the upper envelope of the lithium vs. metallicity distribution increases as we approach solar metallicity. Meteorites, which carry information about the chemical composition of the interstellar medium at the solar system formation time, show a lithium abundance A(Li)~3.26 dex. This pattern reflects the Li enrichment history of the interstellar medium during the Galaxy lifetime. After the initial Li production in Big Bang Nucleosynthesis, the sources of the enrichment include A…
Here we present results from over 500 kiloseconds Chandra and XMM-Newton observations of the cool core of the Centaurus cluster. We investigate the spatial distributions of the O, Mg, Si, S, Ar, Ca, Cr, Mn, Fe, and Ni abundances in the intracluster medium with CCD detectors, and those of N, O, Ne, Mg, Fe, and Ni with the Reflection Grating Spectrometer (RGS). The abundances of most of the elements show a sharp drop within the central 18 arcsec, although different detectors and atomic codes give significantly different values. The abundance ratios of the above elements, including Ne/Fe with RGS…
The enrichment history of heavy neutron-capture elements in the Milky Way disc provides fundamental information about the chemical evolution of our Galaxy and about the stellar sources that made those elements. In this work we give new observational data for Sr, the element at the first neutron-shell closure beyond iron, N=50, based on the analysis of the high resolution spectra of 276 Galactic disc stars. The Sr abundance was derived by comparing the observed and synthetic spectra in the region of the SrI 4607 A line, making use of the LTE approximation. NLTE corrections lead to an increase o…
The thermal and chemical properties of the hot diffuse intragroup medium (IGrM) provide important constraints on the feedback processes associated with massive galaxy formation and evolution. Here we explore these constraints via a detailed analysis of the global properties of simulated z<3 galaxy groups from a cosmological simulation that includes a well-constrained prescription for stellar/supernovae-powered galactic outflows but no AGN feedback. Our aims are to (a) establish a baseline against which we will compare future models; (b) identify model successes due to stellar/supernovae-powere…
Reconstructing chemical enrichment pathways in disc galaxies: A phylogenetic approach
Pontificia Universidad Católica de Chile（智利天主教 Pontificia 大学）；Instituto de Astrofísica, Pontificia Universidad Católica de Chile（智利天主教 Pontificia 大学天体物理研究所）；Centro de Astro-ingeniería, Pontificia Universidad Católica de Chile（智利天主教 Pontificia 大学天文工程中心）；Millenium Nucleus ERIS（ERIS 千年核）；Instituto de Estudios Astrofísicos, Facultad de Ingeniería y Ciencias, Univesidad Diego Portales（迭戈·波特莱斯大学理工与科学学院天体物理研究所）；Research School of Biology, Australian National University（澳大利亚国立大学生物研究学院）；Mathematical Sciences Institute, Australian National University（澳大利亚国立大学数学科学研究所）；Centre for Astrophysics Research, University of Hertfordshire（赫特福德大学天体物理研究中心）
Ripples of Stellar Enrichment (RoSE) - simulating element production and mixing in a Milky Way-mass galactic disc star-by-star
Max-Planck-Institut für Astronomie（马克斯·普朗克天文学研究所）；Research School of Astronomy and Astrophysics, Australian National University（澳大利亚国立大学天文与天体物理研究学院）；Department of Astronomy, The Ohio State University（俄亥俄州立大学天文学系）；Centre for Extragalactic Astronomy, Department of Physics, Durham University（杜伦大学物理系河外天文中心）；Kavli Institute for Astronomy and Astrophysics, Peking University（北京大学柯立夫天文与天体物理研究所）
We investigate nitrogen isotope fractionation in forming and evolving molecular clouds using gas-ice astrochemical simulations. We find that the bulk gas can become depleted in heavy nitrogen (15N) due to the formation of 15N-enriched ices. Around the chemical transition from atomic nitrogen to N2, N15N is selectively photodissociated, which results in the enrichment of 15N in atomic nitrogen. As 15N-enriched atomic nitrogen is converted to ammonia ice via grain surface reactions, the bulk gas is depleted in 15N. The level of 15N depletion in the bulk gas can be up to a factor of two compared …
We interpret recent ALMA observations of z > 6 normal star forming galaxies by means of a semi-numerical method, which couples the output of a cosmological hydrodynamical simulation with a chemical evolution model which accounts for the contribution to dust enrichment from supernovae, asymptotic giant branch stars and grain growth in the interstellar medium. We find that while stellar sources dominate the dust mass of small galaxies, the higher level of metal enrichment experienced by galaxies with Mstar > 10^9 Msun allows efficient grain growth, which provides the dominant contribution to the…
We study the connection of star formation to atomic (HI) and molecular hydrogen (H$_2$) in isolated, low metallicity dwarf galaxies with high-resolution ($m_{\rm gas}$ = 4 M$_\odot$, $N_{\rm ngb}$ = 100) SPH simulations. The model includes self-gravity, non-equilibrium cooling, shielding from an interstellar radiation field, the chemistry of H$_2$ formation, H$_2$-independent star formation, supernova feedback and metal enrichment. We find that the H$_2$ mass fraction is sensitive to the adopted dust-to-gas ratio and the strength of the interstellar radiation field, while the star formation ra…
We develop a hybrid model of galactic chemical evolution that combines a multi-ring computation of chemical enrichment with a prescription for stellar migration and the vertical distribution of stellar populations informed by a cosmological hydrodynamic disc galaxy simulation. Our fiducial model adopts empirically motivated forms of the star formation law and star formation history, with a gradient in outflow mass loading tuned to reproduce the observed metallicity gradient. With this approach, the model reproduces many of the striking qualitative features of the Milky Way disc's abundance str…
We present the discovery of a very hot gas phase of the Milky Way circumgalactic medium (CGM) at T $\approx 10^7$ K, using deep XMM-Newton RGS observations of 1ES 1553+113. The hot gas, coexisting with a warm-hot phase at T $\approx 10^6$ K is $α-$enhanced, with [O/Fe] = 0.9$^{+0.7}_{-0.3}$, indicating core-collapse supernovae enrichment. Additionally we find [Ne/O] and [N/O] = $0.7^{+1.6}_{-0.2}$, such that N/Ne is consistent with solar. Along with the enrichment by AGB stars and core-collapse supernovae, this indicates that some oxygen has depleted onto dust and/or transited to cooler gas ph…
We present new observational data for the heavy elements molybdenum (Mo, Z = 42) and ruthenium (Ru, Z = 44) in F-, G-, and K-stars belonging to different substructures of the Milky Way. The range of metallicity covered is --1.0 $<$ [Fe/H] $<$ +0.3. The spectra of Galactic disc stars have a high resolution of 42,000 and 75,000 and signal-to-noise ratio better than 100. Mo and Ru abundances were derived by comparing the observed and synthetic spectra in the region of Mo I lines at 5506, 5533 Å~ for 209 stars and Ru I lines at 4080, 4584, 4757 Å~ for 162 stars using the LTE approach. For all the …
Chemical abundance variations in the ISM provide important information about the galactic evolution, star-formation and enrichment histories. Recent observations of disk galaxies suggest that if large-scale azimuthal metallicity variations appear in the ISM, they are linked to the spiral arms. In this work, using a set of chemodynamical simulations of the Milky Way-like spiral galaxies, we quantify the impact of gas radial motions~(migration) in the presence of a pre-existing radial metallicity gradient and the local ISM enrichment on both global and local variations of the mean ISM metallicit…
The presence and abundance of short lived radioisotopes (SLRs) $^{26}$Al and $^{60}$Fe in chondritic meteorites implies that the Sun formed in the vicinity of one or more massive stars that exploded as supernovae (SNe). Massive stars are more likely to form in massive star clusters ($>$1000 M$_{\odot}$) than lower mass clusters. However, photoevaporation of protoplanetary discs from massive stars and dynamical interactions with passing stars can inhibit planet formation in clusters with radii of $\sim$1 pc. We investigate whether low-mass (50 - 200 M$_{\odot}$) star clusters containing one or …
The stellar population of the Milky Way bulge is thoroughly studied, with a plethora of measurements from virtually the full suite of instruments available to astronomers. It is thus perhaps surprising that alongside well-established results lies some substantial uncertainty in its star-formation history. Cosmological models predict the bulge to host the Galaxy's oldest stars for [Fe/H]$\lesssim -1$, and this is demonstrated by RR Lyrae stars and globular cluster observations. There is consensus that bulge stars with [Fe/H]$\lesssim0$ are older than $t \approx10$ Gyr. However, at super-solar m…
Water D/H in 3I/ATLAS as a Probe of Formation Conditions in Another Planetary System
University of Michigan（密歇根大学）；NASA Goddard Space Flight Center（美国宇航局戈达德太空飞行中心）；The Catholic University of America（美利坚天主教大学）；Jet Propulsion Laboratory, California Institute of Technology（加州理工学院喷气推进实验室）；Case Western Reserve University（凯斯西储大学）；University of California, Berkeley（加利福尼亚大学伯克利分校）；Observatoire de Paris, Université PSL, CNRS, Sorbonne Université, Université Paris Cité（巴黎天文台，巴黎文理研究大学，法国国家科学研究中心，索邦大学，巴黎西岱大学）
There is mounting evidence that the stellar initial mass function (IMF) could extend much beyond the canonical Mi ~100, Msun limit, but the impact of such hypothesis on the chemical enrichment of galaxies still remains to be clarified. We aim to address this question by analysing the observed abundances of thin- and thick-disc stars in the Milky Way with chemical evolution models that account for the contribution of very massive stars dying as pair-instability supernovae. We built new sets of chemical yields from massive and very massive stars up to Mi ~ 350 Msun, by combining the wind ejecta …
We study galactic enrichment with rapid neutron capture (r-process) elements in cosmological, magnetohydrodynamical simulations of a Milky Way-mass galaxy. We include a variety of enrichment models, based on either neutron star mergers or a rare class of core-collapse supernova as sole r-process sources. For the first time in cosmological simulations, we implement neutron star natal kicks on-the-fly to study their impact. With kicks, neutron star mergers are more likely to occur outside the galaxy disc, but how far the binaries travel before merging also depends on the kick velocity distributi…
The recent aLIGO/aVirgo discovery of gravitational waves from the neutron star merger (NSM) GW170817 and the follow up kilonova observations have shown that NSMs produce copious amount of r-process material. However, it is difficult to reconcile the large natal kicks and long average merging times of Double Neutron Stars (DNSs), with the levels of r-process enrichment seen in ultra faint dwarf (UFD) galaxies such as Reticulum II and Tucana III. Assuming that such dwarf systems have lost a significant fraction of their stellar mass through tidal stripping, we conclude that contrary to most curr…
Abundance anomalies observed in globular cluster stars indicate pollution with material processed by hydrogen burning. Two main sources have been suggested: asymptotic giant branch stars and massive stars rotating near the break-up limit. We discuss the potential of massive binaries as an interesting alternative source of processed material. We discuss observational evidence for mass shedding from interacting binaries. In contrast to the fast, radiatively driven winds of massive stars, this material is typically ejected with low velocity. We expect that it remains inside the potential well of …
As building blocks of dust, rocky planets, and even complex life, the chemical elements heavier than hydrogen (H) and helium (He) - called "metals" in astronomy - play an essential role in our Universe and its evolution. Up to Fe and Ni, these metals are known to be created by stars and stellar remnants via nuclear fusion and to be ejected into their immediate surroundings to enrich new stellar generations. A spectacular finding, however, is that these processed elements are found even outside stellar systems, in particular in the hot, X-ray atmospheres surrounding early-type galaxies and perv…
Coalescing neutron star binary (NSB) systems are primary candidates for $r$-process enrichment of galaxies. The recent detection of $r$-process elements in ultra-faint dwarf (UFD) galaxies and the abundances measured in classical dwarfs challenges the NSB merger scenario both in terms of coalescence time scales and merger locations. In this paper, we focus on the dynamics of NSBs in the gravitational potentials of different types of host galaxies and on its impact on the subsequent galactic enrichment. We find that, for a $\sim t^{-1}$ delay time distribution, even when receiving a low kick ($…
