Red Giant evolution and specific problems

Bressan, A.; Marigo, Paola; Girardi, L.; Nanni, Ambra; Rubele, Stefano

doi:10.1051/epjconf/20134303001

Cited by 71 publications

(89 citation statements)

References 53 publications

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“…2.2. PARSEC v1.1 isochrones (Bressan et al 2013) were employed by the GA to obtain the best-fit cluster parameters, which means the solar metallicity value used to …”

Section: Results On Observed Clustersmentioning

confidence: 99%

ASteCA: Automated Stellar Cluster Analysis

Perren

Vazquez

Piatti

2015

A&A

116

121

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We present the Automated Stellar Cluster Analysis package (ASteCA), a suit of tools designed to fully automate the standard tests applied on stellar clusters to determine their basic parameters. The set of functions included in the code make use of positional and photometric data to obtain precise and objective values for a given cluster's center coordinates, radius, luminosity function and integrated color magnitude, as well as characterizing through a statistical estimator its probability of being a true physical cluster rather than a random overdensity of field stars. ASteCA incorporates a Bayesian field star decontamination algorithm capable of assigning membership probabilities using photometric data alone. An isochrone fitting process based on the generation of synthetic clusters from theoretical isochrones and selection of the best fit through a genetic algorithm is also present, which allows ASteCA to provide accurate estimates for a cluster's metallicity, age, extinction and distance values along with its uncertainties. To validate the code we applied it on a large set of over 400 synthetic The results show that ASteCA is able to recover cluster parameters with an acceptable precision even for those clusters affected by substantial field star contamination. ASteCA is written in Python and is made available as an open source code which can be downloaded ready to be used from its official site.

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“…2.2. PARSEC v1.1 isochrones (Bressan et al 2013) were employed by the GA to obtain the best-fit cluster parameters, which means the solar metallicity value used to …”

Section: Results On Observed Clustersmentioning

confidence: 99%

ASteCA: Automated Stellar Cluster Analysis

Perren

Vazquez

Piatti

2015

A&A

116

121

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“…Note that disruption is still possible for lower BH masses than shown in each region. We include mass-radius relationships for typical WDs from Zalamea et al (2010), MS stars from Tout et al (1996), evolved stars from Bressan et al (2012Bressan et al ( , 2013, and sub-stellar objects from the 1 Gyr curve of Chabrier et al (2009). We define MS stars as M ≥ 0.085 M , brown dwarfs as 0.085 M > M ≥ 13 MJup, and planets as M < 13 MJup.…”

Section: Tidal Disruption Menumentioning

confidence: 99%

Low-mass White Dwarfs with Hydrogen Envelopes as a Missing Link in the Tidal Disruption Menu

Law-Smith

MacLeod

Guillochon

et al. 2017

ApJ

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We construct a menu of objects that can give rise to bright flares when disrupted by massive black holes (BHs), ranging from planets to evolved stars. Through their tidal disruption, main sequence and evolved stars can effectively probe the existence of otherwise quiescent supermassive BHs and white dwarfs can probe intermediate mass BHs. Many low-mass white dwarfs possess extended hydrogen envelopes, which allow for the production of prompt flares in disruptive encounters with moderately massive BHs of 10 5 -10 7 M -masses that may constitute the majority of massive BHs by number. These objects are a missing link in two ways: (1) for probing moderately massive BHs and (2) for understanding the hydrodynamics of the disruption of objects with tenuous envelopes. A flare arising from the tidal disruption of a 0.17 M white dwarf by a 10 5 M BH reaches a maximum between 0.6 and 11 days, with a peak fallback rate that is usually super-Eddington and results in a flare that is likely brighter than a typical tidal disruption event. Encounters stripping only the envelope can provide hydrogen-only fallback, while encounters disrupting the core evolve from H-to He-rich fallback. While most tidal disruption candidates observed thus far are consistent with the disruptions of main sequence stars, the rapid timescales of nuclear transients such as Dougie and PTF10iya are naturally explained by the disruption of low-mass white dwarfs. As the number of observed flares continues to increase, the menu presented here will be essential for characterizing nuclear BHs and their environments through tidal disruptions.

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“…To do this, we make use of the SPSs models of Bressan et al (2012Bressan et al ( , 2013. We use these models because of the current generation of SPS models, which were found to most accurately reproduce the photometry of a large sample of globular clusters and early-type galaxies (age > 2 Gyr) in Paper I of this series (Norris et al 2014).…”

Section: Stellar Population Modelsmentioning

confidence: 99%

Being Wise Ii: Reducing the Influence of Star Formation History on the Mass-to-Light Ratio of Quiescent Galaxies

Norris

Ven

Schinnerer

et al. 2016

ApJ

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The full-text may be used and/or reproduced, and given to third parties in any format or medium, without prior permission or charge, for personal research or study, educational, or not-for-prot purposes provided that:• a full bibliographic reference is made to the original source • a link is made to the metadata record in DRO • the full-text is not changed in any way The full-text must not be sold in any format or medium without the formal permission of the copyright holders.Please consult the full DRO policy for further details. ABSTRACTStellar population synthesis models can now reproduce the photometry of old stellar systems (age > 2 Gyr) in the near-infrared (NIR) bands at 3.4 and 4.6 μm (WISE W1 and W2 or IRAC 1 and 2). In this paper,we derive stellar mass-to-light ratios for these and optical bands, and confirm that the NIR M/L shows dramatically reduced sensitivity to both age and metallicity compared to optical bands, and further, that this behavior leads to significantly more robust stellar masses for quiescent galaxies with [Fe/H]  −0.5 regardless of star-formation history (SFH). We then use realistic early-type galaxy SFHs and metallicity distributions from the EAGLE simulations of galaxy formation to investigate two methods to determine the appropriate M/L for a galaxy.(1) We show that the uncertainties introduced by an unknown SFH can be largely removed using a spectroscopically inferred luminosity-weighted age and metallicity for the population to select the appropriate single stellar population (SSP) equivalent M/L. Using this method, the maximum systematic error due to SFH on the M/L of an early-type galaxy is <4% at 3.4 μm and typical uncertainties due to errors in the age and metallicity create a scatter of 13%. The equivalent values for optical bands are more than two to three times greater, even before considering uncertainties associated with internal dust extinction.(2) We demonstrate that if the EAGLE SFHs and metallicities accurately reproduce the true properties of early-type galaxies, the use of an iterative approach to select a mass dependent M/L can provide even more accurate stellar masses for early-type galaxies, with typical uncertainties of <9%.

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Red Giant evolution and specific problems

Cited by 71 publications

References 53 publications

ASteCA: Automated Stellar Cluster Analysis

ASteCA: Automated Stellar Cluster Analysis

Low-mass White Dwarfs with Hydrogen Envelopes as a Missing Link in the Tidal Disruption Menu

Being Wise Ii: Reducing the Influence of Star Formation History on the Mass-to-Light Ratio of Quiescent Galaxies

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