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Our knowledge of the birth mass function of neutron stars and black holes is based on observations of binary systems but the binary evolution likely affects the final mass of the compact object. Gravitational microlensing allows us to…

Solar and Stellar Astrophysics · Physics 2021-07-30 P. Mroz , A. Udalski , L. Wyrzykowski , J. Skowron , R. Poleski , M. Szymanski , I. Soszynski , K. Ulaczyk

An overview is given of the results obtained about Galactic Structure studies towards the Galactic Centre from star counts. The results indicate the presence of an old, metal-rich population (Z=0.005-0.08; t=13-15 Gyr), presumably the old…

Astrophysics · Physics 2007-05-23 Y. K. Ng

Evolutionary synthesis models for star clusters of various metallicities including gaseous emission during the lifetime of the ionising stars are used to model star cluster systems comprising two populations: an old metal-poor globular…

Astrophysics · Physics 2007-05-23 Uta Fritze -- v. Alvensleben , Peter Anders , Richard de Grijs

We have analyzed the properties of the star formation episodes taking place in a sample of Blue Compact and Irregular galaxies by comparing their multiwavelength observational properties with the predictions of evolutionary population…

Astrophysics · Physics 2007-05-23 J. M. Mas-Hesse , D. Kunth

A series of population models are designed to explore the star formation history of gas-rich, low surface brightness (LSB) galaxies. LSB galaxies are unique in having properties of very blue colors, low H$\alpha$ emission and high gas…

Astrophysics of Galaxies · Physics 2015-06-22 James Schombert , Stacy McGaugh

Red clump giant stars can be used as distance indicators to trace the mass distribution of the Galactic bar. We use RCG stars from 44 bulge fields from the OGLE-II microlensing collaboration database to constrain analytic tri-axial models…

Astrophysics · Physics 2009-06-23 Nicholas J. Rattenbury , Shude Mao , Takahiro Sumi , Martin C. Smith

Photometry and long-slit spectroscopy are presented for 14 S0 and spiral galaxies of the Fornax, Eridanus and Pegasus cluster, and NGC 7582 group. The structural parameters of the galaxies are derived from the R-band images by performing a…

We have observed the largest optical spectra sample of 74 blue compact galaxies. Stellar population properties of them were derived by comparing the equivalent widths of strong absorption features and continuum colors, using a method of…

Astrophysics · Physics 2009-11-07 X. Kong

This paper is a response to recent claims that a population of primordial black holes in the Galactic halo has been ruled out by the OGLE collaboration. This claim was based on the latest results from the OGLE microlensing survey towards…

Astrophysics of Galaxies · Physics 2025-11-19 M. R. S. Hawkins , J. García-Bellido

We present a new Galaxy population synthesis Model (GalMod). GalMod is a star-count model featuring an asymmetric bar/bulge as well as spiral arms and related extinction. The model, initially introduced in Pasetto et al. (2016b), has been…

Astrophysics of Galaxies · Physics 2018-07-04 S. Pasetto , E. K. Grebel , C. Chiosi , D. Crnojevic , P. Zeidler , G. Busso , L. P. Cassara , L. Piovan , R. Tantalo , C. Brogliato

Variations in the photometric parameters of stellar systems as a function of their evolution and the stellar populations comprising them are investigated. A set of seven evolutionary models with an exponential decrease in the star-formation…

Stellar rotation, a key factor influencing stellar structure and evolution, also drives magnetic activity, which is manifested as spots or flares on stellar surface. Here, we present a collection of 18 443 rotating variables located toward…

We investigate the color-magnitude diagram (CMD) of cluster galaxies in the hierarchical $\Lambda$-CDM cosmological scenario using both single stellar populations and simple galaxy models. First, we analyze the effect of bursts and mergers…

Astrophysics of Galaxies · Physics 2019-01-16 Mauro Sciarratta , Cesare Chiosi , Mauro D'Onofrio , Stefano Cariddi

We present the Catalog of microlensing events detected toward the Galactic bulge in three observing seasons, 1997--1999, during the OGLE-II microlensing survey. The search for microlensing events was performed using a database of about…

Astrophysics · Physics 2007-05-23 A. Udalski , K. Zebrun , M. Szymanski , M. Kubiak , G. Pietrzynski , I. Soszynski , P. Wozniak

We present a Bayesian method to determine simultaneously the age, metallicity, distance modulus, and interstellar reddening by dust of any resolved stellar population, by comparing the observed and synthetic color magnitude diagrams on a…

Astrophysics of Galaxies · Physics 2019-05-08 V. H. Ramírez-Siordia , G. Bruzual , B. Cervantes Sodi , T. Bitsakis

We present three color, BVI maps of the Small Magellanic Cloud. The maps contain precise photometric and astrometric data for about 2.2 million stars from the central regions of the SMC bar covering ~2.4 square degrees on the sky. Mean…

Astrophysics · Physics 2007-05-23 A. Udalski , M. Szymanski , M. Kubiak , G. Pietrzynski , P. Wozniak , K. Zebrun

We developed a new semi-analytic galaxy formation model: Galaxy Assembly with Binary Evolution (GABE). For the first time we introduce binary evolution into semi-analytic models of galaxy formation by using Yunnan-II stellar population…

Astrophysics of Galaxies · Physics 2019-11-06 Zhen Jiang , Jie Wang , Liang Gao , Fenghui Zhang , Qi Guo , Lan Wang , Jun Pan

The Optical Gravitational Lensing Experiment (OGLE) is one of the most productive and influential photometric sky surveys in the history of observational astronomy. Originally designed to detect dark matter through gravitational…

Solar and Stellar Astrophysics · Physics 2025-09-12 Patryk Iwanek

Recent advances in stellar population modelling and avalanches of data from mega-surveys have revived the interest in techniques to extract information about galaxy evolution from integrated spectra. This contribution provides an informal…

Astrophysics · Physics 2007-05-23 Roberto Cid Fernandes

We aim to identify the stellar populations (mostly red giants and young stars) detected in the ISOGAL survey at 7 and 15micron towards a field (LN45) in the direction l=-45, b=0.0. The sources detected in the survey of the Galactic plane by…

Astrophysics · Physics 2009-11-13 S. Ganesh , A. Omont , U. C. Joshi , K. S. Baliyan , M. Schultheis , F. Schuller , G. Simon