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- ID:
- ivo://CDS.VizieR/J/ApJ/856/15
- Title:
- Stellar mass-metallicity relation. I.
- Short Name:
- J/ApJ/856/15
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the stellar mass-stellar metallicity relationship (MZR) in the galaxy cluster Cl0024+1654 at z~0.4 using full-spectrum stellar population synthesis modeling of individual quiescent galaxies. The lower limit of our stellar mass range is M*=10^9.7^M_{sun}_, the lowest galaxy mass at which individual stellar metallicity has been measured beyond the local universe. We report a detection of an evolution of the stellar MZR with observed redshift at 0.037+/-0.007dex per Gyr, consistent with the predictions from hydrodynamical simulations. Additionally, we find that the evolution of the stellar MZR with observed redshift can be explained by an evolution of the stellar MZR with the formation time of galaxies, i.e., when the single stellar population (SSP)-equivalent ages of galaxies are taken into account. This behavior is consistent with stars forming out of gas that also has an MZR with a normalization that decreases with redshift. Lastly, we find that over the observed mass range, the MZR can be described by a linear function with a shallow slope ([Fe/H]{propto}(0.16+/-0.03)logM*). The slope suggests that galaxy feedback, in terms of mass-loading factor, might be mass-independent over the observed mass and redshift range.
- ID:
- ivo://CDS.VizieR/J/MNRAS/460/2862
- Title:
- Stellar mass of brightest cluster galaxies
- Short Name:
- J/MNRAS/460/2862
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Using a sample of 98 galaxy clusters recently imaged in the near-infrared with the European Southern Observatory (ESO) New Technology Telescope, WIYN telescope and William Herschel Telescope, supplemented with 33 clusters from the ESO archive, we measure how the stellar mass of the most massive galaxies in the universe, namely brightest cluster galaxies (BCGs), increases with time. Most of the BCGs in this new sample lie in the redshift range 0.2<z<0.6, which has been noted in recent works to mark an epoch over which the growth in the stellar mass of BCGs stalls. From this sample of 132 clusters, we create a subsample of 102 systems that includes only those clusters that have estimates of the cluster mass. We combine the BCGs in this subsample with BCGs from the literature, and find that the growth in stellar mass of BCGs from 10 billion years ago to the present epoch is broadly consistent with recent semi-analytic and semi-empirical models. As in other recent studies, tentative evidence indicates that the stellar mass growth rate of BCGs may be slowing in the past 3.5 billion years. Further work in collecting larger samples, and in better comparing observations with theory using mock images, is required if a more detailed comparison between the models and the data is to be made.
- ID:
- ivo://CDS.VizieR/J/MNRAS/506/928
- Title:
- Stellar mass-size relation for low M* galaxies
- Short Name:
- J/MNRAS/506/928
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We reliably extend the stellar mass-size relation over 0.2<=z<=2 to low stellar mass galaxies by combining the depth of Hubble Frontier Fields (HFF) with the large volume covered by CANDELS. Galaxies are simultaneously modelled in multiple bands using the tools developed by the MegaMorph project, allowing robust size (i.e., half-light radius) estimates even for small, faint, and high redshift galaxies. We show that above 10^7^M_{sun}_, star-forming galaxies are well represented by a single power law on the mass-size plane over our entire redshift range. Conversely, the stellar mass - size relation is steep for quiescent galaxies with stellar masses >=10^10.3^M_{sun}_ and flattens at lower masses, regardless of whether quiescence is selected based on star-formation activity, rest-frame colours, or structural characteristics. This flattening occurs at sizes of ~1kpc at z<=1. As a result, a double power law is preferred for the stellar mass-size relation of quiescent galaxies, at least above 10^7^M_{sun}_. We find no strong redshift dependence in the slope of the relation of star-forming galaxies as well as of high mass quiescent galaxies. We also show that star-forming galaxies with stellar masses >=10^9.5^M_{sun}_ and quiescent galaxies with stellar masses>=10^10.3^M_{sun}_ have undergone significant size growth since z~2, as expected; however, low mass galaxies have not. Finally, we supplement our data with predominantly quiescent dwarf galaxies from the core of the Fornax cluster, showing that the stellar mass-size relation is continuous below 10^7^M_{sun}_, but a more complicated functional form is necessary to describe the relation.
- ID:
- ivo://CDS.VizieR/J/ApJ/821/101
- Title:
- Stellar MFP for massive quiescent z<0.7 galaxies
- Short Name:
- J/ApJ/821/101
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We examine the evolution of the relation between stellar mass surface density, velocity dispersion, and half-light radius --the stellar mass fundamental plane (MFP)-- for quiescent galaxies at z<0.6. We measure the local relation from galaxies in the Sloan Digital Sky Survey and the intermediate redshift relation from ~500 quiescent galaxies with stellar masses 10<~log(M*/M_{sun}_)<~11.5. Nearly half of the quiescent galaxies in our intermediate redshift sample are compact. After accounting for important selection and systematic effects, the velocity dispersion distribution of galaxies at intermediate redshifts is similar to that of galaxies in the local universe. Galaxies at z<0.6 appear to be smaller (<~0.1dex) than galaxies in the local sample. The orientation of the stellar MFP is independent of redshift for massive quiescent galaxies at z<0.6 and the zero-point evolves by ~0.04dex. Compact quiescent galaxies fall on the same relation as the extended objects. We confirm that compact quiescent galaxies are the tail of the size and mass distribution of the normal quiescent galaxy population.
- ID:
- ivo://CDS.VizieR/J/A+A/624/A137
- Title:
- Stellar models and isochrones
- Short Name:
- J/A+A/624/A137
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Grids of stellar models are useful tools to derive the properties of stellar clusters, in particular young clusters hosting massive stars, and to provide information on the star formation process in various mass ranges. Because of their short evolutionary timescale, massive stars end their life while their low-mass siblings are still on the pre-main sequence (pre-MS) phase. Thus the study of young clusters requires consistent consideration of all the phases of stellar evolution. But despite the large number of grids that are available in the literature, a grid accounting for the evolution from the pre-MS accretion phase to the post-MS phase in the whole stellar mass range is still lacking. We build a grid of stellar models at solar metallicity with masses from 0.8M_{sun}_ to 120M_{sun}_, including pre-MS phase with accretion. We use the GENEC code to run stellar models on this mass range. The accretion law is chosen to match the observations of pre-MS objects on the Hertzsprung-Russell diagram. We describe the evolutionary tracks and isochrones of our models. The grid is connected to previous MS and post-MS grids computed with the same numerical method and physical assumptions, which provides the widest grid in mass and age to date.
- ID:
- ivo://CDS.VizieR/J/A+AS/96/269
- Title:
- Stellar Models from 0.8 to 120 Msolar
- Short Name:
- J/A+AS/96/269
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- New grids of stellar evolutionary models covering the range of 0.8 to 120 solar masses have been computed for metallicites Z=0.020 and Z=0.001. The models use the new opacities by Rogers and Iglesias (1992ApJS...79..507R) and by Kurucz (1991) at low T. The consequent changes in the solar helium content, in the mixing length ratio and in the overshooting parameter are taken into account after careful calibrations. Important physical ingredients as the nuclear reaction rates and the neutrino loss rates have been updated. The ionization of the main heavy elements is calculated in details. Results of the models are given in a compact way at corresponding evolutionary stages in each model. In addition to the tables, we shortly present some general results on the tracks in the HR diagrams, the lifetimes in the H-, He-, C-burning phases, and on massive and WR stars.
- ID:
- ivo://CDS.VizieR/J/A+A/628/A29
- Title:
- Stellar models grids (Z=0.0134-0.00134) 0.8-35Msun
- Short Name:
- J/A+A/628/A29
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The theoretical apsidal motion constants are key tools to investigate the stellar interiors in close eccentric binary systems. In addition, these constants and the moment of inertia are also important to investigate the tidal evolution of close binary stars as well as of exo-planetary systems. The aim of the paper is to present new evolutionary models, based on the MESA package, that include the internal structure constants (k_2_, k_3_, and k_4_), the radius of gyration, and the gravitational potential energy for configurations computed from the pre-main-sequence (PMS) up to the first ascent giant branch or beyond. The calculations are available for the three metallicities [Fe/H] = 0.00, -0.50, and -1.00, which take the recent investigations in less metallic environments into account. This new set of models replaces the old ones, published about 15 years ago, using the code GRANADA. Core overshooting was taken into account using the mass-f_ov_ relationship, which was derived semi-empirically for models more massive than 1.2M_{sun}_. The differential equations governing the apsidal motion constants, moment of inertia, and the gravitational potential energy were integrated simultaneously through a fifth-order Runge-Kutta method with a tolerance level of 10^-7^. The resulting models (from 0.8 up to 35.0M_{sun}_) are presented in 54 tables for the three metallicities, containing the usual characteristics of an evolutionary model (age, initial masses, logT_eff_, logg, and logL), the constants of internal structure (k_2_, k_3_, and k_4_), the radius of gyration {beta} and the factor {alpha} that is related with the gravitational potential energy.
- ID:
- ivo://CDS.VizieR/J/A+A/424/919
- Title:
- Stellar models grids. Z=0.02, M=0.8 to 125
- Short Name:
- J/A+A/424/919
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present new stellar models based on updated physics (opacities, expanded nuclear network and mass loss rates). We compute stellar models suitable for the mean solar neighborhood, i.e. for Z=0.02 and X=0.70. The covered mass range is from 0.8 up to 125M_{sun}_ and the models are followed until the exhaustion of carbon in the core, for the more massive ones. In addition, the effective temperatures of the more massive models are corrected for the effects of stellar winds, while models with lower effective temperatures are computed using a special treatment of the equation of state (CEFF). Convective core overshooting is assumed to be moderate and is modelled with alpha_ov_=0.20. Besides the classical ingredients of stellar models, we also provide the internal structure constants needed to investigate apsidal motion and tidal evolution in close binaries. The latter constants are made public for the first time. According to the current theories of tidal evolution, the time scales for synchronization and circularization for cool stars depend -- apart from the mass, radius and effective temperature -- on the depth of the convective envelope x_bf_ and on the radius of gyration {beta}. For stars with higher effective temperatures, these dependencies are mainly incorporated in the tidal torque constant E_2_. All these parameters are steep functions of mass and time, and thus require a special numerical treatment. The new mass loss formalism produces more mass concentrated configurations than previously, especially for more massive and more evolved stellar models. As the present grid is designed mainly for the study of double-lined eclipsing binaries, the gravity-darkening exponents necessary to calculate the surface brightness distribution in rotationally and/or tidally distorted stars are computed following the method described recently by Claret (1998, Cat. <J/A+AS/133/123>), and made available for each point of every evolutionary track.
- ID:
- ivo://CDS.VizieR/J/A+A/605/A102
- Title:
- Stellar models. 0.85<M<6, Z=0.0001-0.014
- Short Name:
- J/A+A/605/A102
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Recent spectropolarimetric observations of otherwise ordinary (in terms e.g. of surface rotation and chemical properties) G, K, and M giants have revealed localized magnetic strips in the Hertzsprung-Russell diagram coincident with the regions where the first dredge-up and core helium burning occur. We seek to understand the origin of magnetic fields in such late-type giant stars, which is currently unexplained. In analogy with late-type dwarf stars, we focus primarily on parameters known to influence the generation of magnetic fields in the outer convective envelope. We compute the classical dynamo parameters along the evolutionary tracks of low- and intermediate-mass stars at various metallicities using stellar models that have been extensively tested by spectroscopic and asteroseismic observations. Specifically, these include convective turnover timescales and convective Rossby numbers, computed from the pre-main sequence (PMS) to the tip of the red giant branch (RGB) or the early asymptotic giant branch (AGB) phase. To investigate the effects of the very extended outer convective envelope, we compute these parameters both for the entire convective envelope and locally, that is, at different depths within the envelope. We also compute the turnover timescales and corresponding Rossby numbers for the convective cores of intermediate-mass stars on the main sequence. Our models show that the Rossby number of the convective envelope becomes lower than unity in the well-delimited locations of the Hertzsprung-Russell diagram where magnetic fields have indeed been detected. We show that {alpha}-{Omega} dynamo processes might not be continuously operating, but that they are favored in the stellar convective envelope at two specific moments along the evolution tracks, that is, during the first dredge-up at the base of the RGB and during central helium burning in the helium-burning phase and early-AGB. This general behavior can explain the so-called magnetic strips recently discovered by dedicated spectropolarimetric surveys of evolved stars.