We present the PMAS/PPak Integral-field Supernova hosts COmpilation (PISCO), which comprises integral field spectroscopy (IFS) of 232 supernova (SN) host galaxies that hosted 272 SNe, observed over ...several semesters with the 3.5 m telescope at the Calar Alto Observatory (CAHA). PISCO is the largest collection of SN host galaxies observed with wide-field IFS, totaling 466,347 individual spectra covering a typical spatial resolution of ∼380 pc. Focused studies regarding specific SN Ia-related topics will be published elsewhere; this paper aims to present the properties of the SN environments, using stellar population (SP) synthesis, and the gas-phase interstellar medium, providing additional results separating stripped-envelope SNe into their subtypes. With 11,270 H ii regions detected in all galaxies, we present for the first time a statistical analysis of H ii regions, which puts H ii regions that have hosted SNe in context with all other star-forming clumps within their galaxies. SNe Ic are associated with environments that are more metal-rich and have higher EW(H ) and higher star formation rate within their host galaxies than the mean of all H ii regions detected within each host. This in contrast to SNe IIb, which occur in environments that are very different compared to other core-collapse SNe types. We find two clear components of young and old SPs at SNe IIn locations. We find that SNe II fast decliners tend to explode at locations where the SFR is more intense. Finally, we outline how a future dedicated IFS survey of galaxies in parallel to an untargeted SN search would overcome the biases in current environmental studies.
ABSTRACT
Due to its proximity, the stellar populations of the Galactic bulge (GB) can be resolved and can be studied in detail. This allows tracing the bulge metallicity distribution function (MDF) ...for different spatial regions within the bulge, which may give us clues about the bulge formation and evolution scenarios. In this work, we developed a chemical evolution model (CEM), taking into account the mass distribution in the bulge and disc, to derive the radial dependence of this time-scale in the Galaxy. Since the infall rate depends on that time-scale in the CEM, the results of the model were used to test a scenario where the bulge is formed inside-out. The obtained results for the α/Fe versus Fe/H relationship, the MDF and the Fe/H radial gradient in the bulge have been compared to available data in the literature. The model is able to reproduce most of the observational data: the spread in the relation α/Fe versus Fe/H, the MDF shape in different regions of the bulge, the Fe/H radial gradient inside it, and the age–metallicity relation, as well as the α/Fe evolution with age. The results of the model point to a scenario where the bulk of the bulge stars pre-existed the boxy/peanut X-shape bar formation. As a result, the classical origin of the GB is not ruled out, and this scenario may be invoked to explain the chemical properties of the GB.
ABSTRACT
Dust plays an important role in the evolution of a galaxy, as it is one of the main ingredients for efficient star formation. Dust grains are also a sink/source of metals when they are ...created/destroyed, and, therefore, a self-consistent treatment is key in order to correctly model chemical evolution. In this work, we discuss the implementation of dust physics in our current multiphase model, which also follows the evolution of atomic, ionized and molecular gas. Our goal is to model the conversion rates among the different phases of the interstellar medium, including the creation, growth and destruction of dust, based, as far as possible, on physical principles rather than on phenomenological recipes. We first present the updated set of differential equations and then discuss the results. We calibrate our model against observations of the Milky Way Galaxy and compare its predictions with extant data. Our results are broadly consistent with the observed data for intermediate and high metallicities, but the models tend to produce more dust than is observed in the low-metallicity regime.
PopStar I: evolutionary synthesis model description Mollá, M.; García-Vargas, M. L.; Bressan, A.
Monthly notices of the Royal Astronomical Society,
September 2009, Letnik:
398, Številka:
1
Journal Article
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We present new evolutionary synthesis models for simple stellar populations for a wide range of ages and metallicities. The models are based on the Padova isochrones. The core of the spectral library ...is provided by the medium resolution Lejeune et al. atmosphere models. These spectra are complemented by Non Local Thermodynamic Equilibrium (NLTE) atmosphere models for hot stars that have an important impact on the stellar cluster's ionizing spectra: O, B and WR stellar spectra at the early ages, and spectra of post asymptotic giant branch stars and planetary nebulae, at intermediate and old ages. At young ages, our models compare well with other existing models, but we find that the inclusion of the nebular continuum, not considered in several other models, significantly reddens the integrated colours of very young stellar populations. This is consistent with the results of spectral synthesis codes particularly devised for the study of starburst galaxies. At intermediate and old ages, the agreement with the literature model is good and, in particular, we reproduce the observed colours of star clusters in Large Magellanic Cloud well. Given the ability to produce good integrated spectra from the far-ultraviolet to the infrared at any age, we consider that our models are particularly suited for the study of high-redshift galaxies. These models are available on the web site http://www.fractal-es.com/SEDmod.htm and also through the Virtual Observatory Tools on the PopStar server.
ABSTRACT
We carry out 1D hydrodynamical simulations of the evolution of a spherically symmetric supernova remnant (SNR) subject to an external radiation field (ERF) that influences the cooling and ...heating rates of the gas. We consider homogeneous media with ambient hydrogen number densities nH, 0 of 0.1 and 1 cm−3 permeated by an average radiation field including the cosmic microwave, extragalactic, and Galactic backgrounds, attenuated by an effective column density NH, eff from 1018 to 1021 cm−2. Our results may be classified into two broad categories: at low NH, eff, the ERF presents little absorption in the ultraviolet (ionizing) regime, and all the ’unshielded’ cases feature an equilibrium temperature Teq ∼ 7000 K below which the ambient gas cannot cool further. In this scenario, the SNR develops a nearly isothermal shock profile whose shell becomes thicker over time. At higher NH, eff, the ERF is heavily absorbed in the UV range, yielding a roughly constant heating function for temperatures ≲ 104 K. These ‘shielded’ cases develop a thin, cold and dense shell throughout their evolution. Energy and momentum injection to the medium do not change significantly between both scenarios, albeit luminosity is higher and more uniformly distributed over the shell for unshielded SNR.
We measured the gas abundance profiles in a sample of 122 face-on spiral galaxies observed by the CALIFA survey and included all spaxels whose line emission was consistent with star formation. This ...type of analysis allowed us to improve the statistics with respect to previous studies, and to properly estimate the oxygen distribution across the entire disc to a distance of up to 3−4 disc effective radii (re). We confirm the results obtained from classical H ii region analysis. In addition to the general negative gradient, an outer flattening can be observed in the oxygen abundance radial profile. An inner drop is also found in some cases. There is a common abundance gradient between 0.5 and 2.0 re of αO / H = − 0.075 dex /re with a scatter of σ = 0.016 dex /re when normalising the distances to the disc effective radius. By performing a set of Kolmogorov-Smirnov tests, we determined that this slope is independent of other galaxy properties, such as morphology, absolute magnitude, and the presence or absence of bars. In particular, barred galaxies do not seem to display shallower gradients, as predicted by numerical simulations. Interestingly, we find that most of thegalaxies in the sample with reliable oxygen abundance values beyond ~2 effective radii (57 galaxies) present a flattening of the abundance gradient in these outer regions. This flattening is not associated with any morphological feature, which suggests that it is a common property of disc galaxies. Finally, we detect a drop or truncation of the abundance in the inner regions of 27 galaxies in the sample; this is only visible for the most massive galaxies.
ABSTRACT
We present the HR-pyPopStar model, which provides a complete set (in ages) of high-resolution (HR) spectral energy distributions of Single Stellar Populations. The model uses the most recent ...high-wavelength-resolution theoretical atmosphere libraries for main-sequence, post-AGB/planetary nebulae and Wolf–Rayet stars. The spectral energy distributions are given for more than a hundred ages ranging from 0.1 Myr to 13.8 Gyr, at four different values of the metallicity (Z = 0.004, 0.008, 0.019, and 0.05), considering four different IMFs. The wavelength range goes from 91 to $24\, 000$ Å in linear steps δλ = 0.1 Å, giving a theoretical resolving power $R_{{\rm th},5000} \sim 50\, 000$ at 5000 Å. This is the main novelty of these spectra, unique for their age and wavelength ranges. The models include the ionizing stellar populations that are relevant at both young (massive hot stars) and old (planetary nebulae) ages. We have tested the results with some examples of HR spectra recently observed with MEGARA at GTC. We highlight the importance of wavelength resolution in reproducing and interpreting the observational data from the last and forthcoming generations of astronomical instruments operating at 8–10 m class telescopes, with higher spectral resolution than their predecessors.
In the absence of an interaction, central bars might be the most effective mechanism for radial motions of gas in barred spiral galaxies, which represent two-thirds of disc galaxies. The dynamical ...effects induced by bars in the first few kpc of discs might play an important role in the disc profiles in this region. In this work, a chemical evolution model with radial gas flows is proposed in order to mimic the effects of the Milky Way bar in the bulge and inner disc. The model is an update of a chemical evolution model with the inclusion of radial gas flows in the disc and bulge. The exchange of gas between the cylindrical concentric regions that form the Galaxy is modelled considering the flows of gas from and to the adjacent cylindrical regions. The most recent data for the bulge metallicity distribution are reproduced by means of a single and longer bulge collapse time-scale (2 Gyr) than other chemical evolution models predict. The model is able to reproduce the peak in the present star formation rate at 4 kpc and the formation of the molecular gas ring. The model with a bar predicts a flattening of the oxygen radial gradient of the disc. Additionally, models with radial gas flows predict a higher star formation rate during the formation of the bulge. This is in agreement with the most recent observations of the star formation rate at the centre of massive barred spiral galaxies.
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