Fingerprint of the first stars: multi-enriched extremely metal-poor stars in the TOPoS survey

Hartwig, Tilman; Ishigaki, Miho N.; Klessen, Ralf S.; Yoshida, Naoki

doi:10.1093/mnras/sty2783

Cited by 36 publications

(25 citation statements)

References 56 publications

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“…A similar analysis in implemented in Youakim et al (2017, hereafter KY17) used the Powel's truncated Newton algorithm to find the best fit solution. However, for this work we also use a Markov Chain Monte Carlo (MCMC) algorithm based on self-adaptative randomized subspace sampling (Vrug et al 2009), which provides the added advantage of deriving uncertainties by 2 FERRE is available from http://github.com/callendeprieto/ferre 4.5 5.0 5.5 6.0 6.5 7.0 Teff spectroscopic (10 3 K) 4.5 5.0 5.5 6.0 6.5 7.0 Teff photometric ( sampling the probability distribution function. The grid of synthetic spectra spans the space −6 ≤ [Fe/H] ≤ −2, −1 ≤ [C/Fe] ≤ 5, 4750 K ≤ T eff ≤ 7000 K and 1.0 ≤ log g ≤ 5.0.…”

Section: Analysis With Ferrementioning

confidence: 99%

The Pristine survey – VI. The first three years of medium-resolution follow-up spectroscopy of Pristine EMP star candidates

Aguado

Youakim

Hernández

et al. 2019

Monthly Notices of the Royal Astronomical Society

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We present the results of a 3-year long, medium-resolution spectroscopic campaign aimed at identifying very metal-poor stars from candidates selected with the CaHK, metallicity-sensitive Pristine survey. The catalogue consists of a total of 1007 stars, and includes 146 rediscoveries of metal-poor stars already presented in previous surveys, 707 new very metal-poor stars with [Fe/H] < −2.0, and 95 new extremely metal-poor stars with [Fe/H] < −3.0. We provide a spectroscopic [Fe/H] for every star in the catalogue, and [C/Fe] measurements for a subset of the stars (10% with [Fe/H] < −3 and 24% with −3 < [Fe/H] < −2) for which a carbon determination is possible, contingent mainly on the carbon abundance, effective temperature and S/N of the stellar spectra. We find an average carbon enhancement fraction ([C/Fe] ≥ +0.7) of 41 ± 4% for stars with −3 < [Fe/H] < −2 and 58 ± 14% for stars with [Fe/H] < −3, and report updated success rates for the Pristine survey of 56 % and 23 % to recover stars with [Fe/H] < −2.5 and [Fe/H] < −3, respectively. Finally, we discuss the current status of the survey and its preparation for providing targets to upcoming multi-object spectroscopic surveys such as WEAVE.

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Section: Analysis With Ferrementioning

confidence: 99%

The Pristine survey – VI. The first three years of medium-resolution follow-up spectroscopy of Pristine EMP star candidates

Aguado

Youakim

Hernández

et al. 2019

Monthly Notices of the Royal Astronomical Society

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“…They are further classified into Population III.1 (the first generation of stars) and Population III.2 (primordial stars affected by radiation from other stars, see McKee & Tan 2008;De Souza et al 2011). While contemporary star formation is well studied thanks to observations and simulations, the formation of the first generation of stars in the Universe still remains a mystery because of the lack of direct observations at spatially resolved scales beyond z > 11.1 (Oesch et al 2016), and of zero-metallicity stars, if any, in the Local Group (Griffen et al 2018;Hartwig et al 2019).…”

Section: Introductionmentioning

confidence: 99%

The role of the H2 adiabatic index in the formation of the first stars

Sharda

Krumholz

Federrath

2019

Monthly Notices of the Royal Astronomical Society

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The adiabatic index of H 2 (γ H 2 ) is non-constant at temperatures between 100 − 10 4 K due to the large energy spacing between its rotational and vibrational modes. For the formation of the first stars at redshifts 20 and above, this variation can be significant because primordial molecular clouds are in this temperature range due to the absence of efficient cooling by dust and metals. We study the possible importance of variations in γ H 2 for the primordial initial mass function by carrying out 80 3D gravito-hydrodynamic simulations of collapsing clouds with different random turbulent velocity fields, half using fixed γ H 2 = 7/5 in the limit of classical diatomic gas (used in earlier works) and half using an accurate quantum mechanical treatment of γ H 2 . We use the adaptive mesh refinement code FLASH with the primordial chemistry network from KROME for this study. The simulation suite produces almost 400 stars, with masses from 0.02 − 50 M (mean mass ∼ 10.5 M and mean multiplicity fraction ∼ 0.4). While the results of individual simulations do differ when we change our treatment of γ H 2 , we find no statistically significant differences in the overall mass or multiplicity distributions of the stars formed in the two sets of runs. We conclude that, at least prior to the onset of radiation feedback, approximating H 2 as a classical diatomic gas with γ H 2 = 7/5 does not induce significant errors in simulations of the fragmentation of primordial gas. Nonetheless, we recommend using the accurate formulation of the H 2 adiabatic index in primordial star formation studies since it is not computationally more expensive and provides a better treatment of the thermodynamics.

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“…One of the most promising routes of indirectly probing the IMF of the first stars is through stellar archaeology -the approach of surveying local stellar fossils for vestiges of the early Universebased on observing the elemental abundance patterns in extremely metal poor (EMP) stars. In principle, this would allow us to distinguish different supernova (SN) types that have enriched the gas out of which second-generation, Population II (Pop II), stars form (Beers & Christlieb 2005;Frebel 2010;Chen et al 2017;Ishigaki et al 2018;Hartwig et al 2019). The nucleosynthetic imprint on Pop II stars would thus impose bounds on the IMF of the first stars, with numerous studies along these lines (e.g.…”

Section: Introductionmentioning

confidence: 99%

Probing the initial mass function of the first stars with transients

Lazar,

Bromm

2021

Preprint

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The emergence of the first, so-called Population III (Pop III), stars shaped early cosmic history in ways that crucially depends on their initial mass function (IMF). However, because of the absence of direct observational constraints, the detailed IMF remains elusive. Nevertheless, numerical simulations agree in broad terms that the first stars were typically massive and should often end their lives in violent, explosive deaths. These fates include extremely luminous pair-instability supernovae (PISNe) and bright gamma-ray bursts (GRBs), the latter arising from the collapse of rapidly rotating progenitor stars into black holes. These high-redshift transients are expected to be within the detection limits of upcoming space telescope missions, allowing to place effective constraints on the shape of the primordial IMF that is not easily accessible with other probes. This paper presents a framework to probe the Pop III IMF, utilizing the cosmological source densities of high-redshift PISNe and GRBs. Considering these transients separately could provide useful constraints on the Pop III IMF, but tighter bounds are obtainable by combining PISN and GRB counts. This combined diagnostic is more robust as it is independent of the underlying Pop III star formation rate density, an unknown prior. Future surveys promise to capture most high-redshift GRBs across the entire sky, but high-redshift PISN searches with future telescopes, e.g. Roman Space Telescope, will likely be substantially incomplete. Nevertheless, we demonstrate that even such lower bounds on the PISN count will be able to provide key constraints on the primordial IMF, in particular, if it is top-heavy or not.

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Fingerprint of the first stars: multi-enriched extremely metal-poor stars in the TOPoS survey

Cited by 36 publications

References 56 publications

The Pristine survey – VI. The first three years of medium-resolution follow-up spectroscopy of Pristine EMP star candidates

The Pristine survey – VI. The first three years of medium-resolution follow-up spectroscopy of Pristine EMP star candidates

The role of the H2 adiabatic index in the formation of the first stars

Probing the initial mass function of the first stars with transients

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