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Statistical inference in observational science typically relies on a fundamental assumption: as sample size increases and uncertainties decrease, the inferred results should converge to the true physical quantities. This assumption…

Machine Learning · Computer Science 2026-05-01 Zhipeng Zhang

The variation of metal production over time and its dilution in the interstellar medium depend on the star formation and gas accretion rates. Measuring age-chemistry relations across the Milky Way disk provides key constraints on the gas…

Astrophysics of Galaxies · Physics 2025-05-28 Valeria Cerqui , Misha Haywood , Owain Snaith , Paola Di Matteo , Laia Casamiquela

We study the impact on stellar age determination by means of grid-based techniques adopting asteroseismic constraints of the uncertainty in the radiative opacity, in the initial helium abundance, in the mixing-length value, in the…

Solar and Stellar Astrophysics · Physics 2015-02-11 G. Valle , M. Dell'Omodarme , P. G. Prada Moroni , S. Degl'Innocenti

The evolution history of the Milky Way disk is imprinted in the ages, positions, and chemical compositions of individual stars. In this study, we derive the intrinsic density distribution of different stellar populations using the final…

We present our new, fully-automated method to detect and measure the ages of star clusters in nearby galaxies, where individual stars can be resolved. The method relies purely on statistical analysis of observations and Monte-Carlo…

Understanding the ages of stars is crucial for unraveling the formation history and evolution of our Galaxy. Traditional methods for estimating stellar ages from spectroscopic data often struggle with providing appropriate uncertainty…

We present a summary of our recent work on the vertical distribution of the resolved stellar populations in six low mass, edge-on, spiral galaxies observed with the Hubble Space Telescope Advanced Camera for Surveys (HST/ACS). In each…

Astrophysics · Physics 2007-05-23 Anil Seth , Julianne Dalcanton , Roelof de Jong

The determination of stellar populations of galaxies are important for studying the formation and evolution of galaxies, because all galaxies contain many stars and they evolve with galaxies. Spectra data are usually used to determine the…

Solar and Stellar Astrophysics · Physics 2013-02-04 Zhongmu Li

The detailed study of the Galactic bulge stellar population necessarily requires an accurate representation of the interstellar extinction particularly toward the Galactic plane and center, where the severe and differential reddening is…

Astrophysics of Galaxies · Physics 2021-01-04 F. Surot , E. Valenti , O. A. Gonzalez , M. Zoccali , E. Sökmen , S. L. Hidalgo , D. Minniti

Physical parameters of galaxies (as luminosity, stellar mass, age) are often derived by means of the model templates which best fit their spectro-photometric data. We have performed a quantitative test aimed at exploring the ability of this…

Astrophysics · Physics 2010-11-11 Marcella Longhetti , Paolo Saracco , Arturo Mignano

Photometric and astrometric monitoring of directly imaged exoplanets will deliver unique insights into their rotational periods, the distribution of cloud structures, weather, and orbital parameters. As the host star is occulted by the…

Instrumentation and Methods for Astrophysics · Physics 2020-07-01 Steven P. Bos

The first generations of stars left their chemical fingerprints on metal-poor stars in the Milky Way and its surrounding dwarf galaxies. While instantaneous and homogeneous enrichment implies that groups of co-natal stars should have the…

Astrophysics of Galaxies · Physics 2024-10-16 Jennifer Mead , Melissa Ness , Eric Andersson , Emily J. Griffith , Danny Horta

We live in an age where an enormous amount of astrometric, photometric, asteroseismic, and spectroscopic data of Milky Way stars are being acquired, many orders of magnitude larger than about a decade ago. Thanks to the Gaia astrometric…

Astrophysics of Galaxies · Physics 2018-06-13 Ivan Minchev

In the age of high-resolution spectroscopic stellar surveys of the Milky Way, the number of stars with detailed abundances of multiple elements is rapidly increasing. These elemental abundances are directly influenced by the evolutionary…

Variable stars play a key role in understanding the Milky Way and the universe. The era of astronomical big data presents new challenges for quick identification of interesting and important variable stars. Accurately estimating the periods…

Instrumentation and Methods for Astrophysics · Physics 2022-12-21 Xiao-Hui Xu , Qing-Feng Zhu , Xu-Zhi Li , Bin Li , Hang Zheng , Jin-Sheng Qiu , Hai-Bin Zhao

Various methods for age dating globular clusters in ellipticals are presented. We first present spectroscopy of individual globular clusters (feasible with the advent of the 10m-class telescopes), and the measurement of Balmer line indices.…

Astrophysics · Physics 2007-05-23 Markus Kissler-Patig

By adopting the recently empirically derived dependence of $\alpha$-elements on $[\alpha/{\rm Fe}]$ instead of the conventionally applied uniform one, we tested the agreement between stellar model predictions and observations for red giant…

Solar and Stellar Astrophysics · Physics 2024-08-28 G. Valle , M. Dell'Omodarme , P. G. Prada Moroni , S. Degl'Innocenti

We present the first asymmetric drift (AD) measurements for unresolved stellar populations of different characteristic ages above and below 1.5 Gyr. These measurements sample the age-velocity relation (AVR) in galaxy disks. In this first…

Asteroseismology of bright stars with well-determined properties from parallax measurements and interferometry can yield precise stellar ages and meaningful constraints on the composition. We substantiate this claim with an updated…

Solar and Stellar Astrophysics · Physics 2015-10-05 Travis S. Metcalfe , Orlagh L. Creevey , Guy R. Davies

We describe a simple step-by-step guide to qualitative interpretation of galaxy spectra. Rather than an alternative to existing automated tools, it is put forward as an instrument for quick-look analysis, and for gaining physical insight…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-05 J. Sanchez Almeida , R. Terlevich , E. Terlevich , R. Cid Fernandes , A. B. Morales-Luis