English
Related papers

Related papers: A Puzzle Involving Galactic Bulge Microlensing Eve…

200 papers

While the number of stars in the Galactic bulge with detailed chemical abundance measurements is increasingly rapidly, the inner Galactic bulge ( |b| < 2$^\circ$) remains poorly studied, due to heavy interstellar absorption and photometric…

Astrophysics of Galaxies · Physics 2018-05-23 G. Nandakumar , N. Ryde , M. Schultheis , B. Thorsbro , H. Jönsson , P. S. Barklem , R. M. Rich , F. Fragkoudi

CONTEXT: [ABRIDGED]. For the Milky Way bulge, there are currently essentially no measurements of carbon in un-evolved stars, hampering our abilities to properly compare Galactic chemical evolution models to observational data for this still…

Astrophysics of Galaxies · Physics 2021-12-01 T. Bensby , A. Gould , M. Asplund , S. Feltzing , J. Meléndez , J. A. Johnson , S. Lucatello , A. Udalski , J. C. Yee

Following the suggestion of Gould and Depoy (1998) we investigate the feasibility of studying the brightest microlensing events towards the Galactic bulge using a small aperture (~10 cm) telescope. We used one of the HAT telescopes to…

Astrophysics of Galaxies · Physics 2009-05-01 D. M. Nataf , K. Z. Stanek , G. A. Bakos

We analyse the effects on the predictions for the microlensing searches toward the Galactic bulge coming from the fact that not all the stars monitored belong to the bulge itself, but that a non--negligible fraction of them actually are in…

Astrophysics · Physics 2009-10-28 S. Mollerach , E. Roulet

AIMS. Our aims are twofold. First we aim to evaluate the robustness and accuracy of stellar parameters and detailed elemental abundances that can be derived from high-resolution spectroscopic observations of microlensed dwarf and subgiant…

Astrophysics of Galaxies · Physics 2015-05-13 T. Bensby , J. A. Johnson , J. Cohen , S. Feltzing , A. Udalski , A. Gould , W. Huang , I. Thompson , J. Simmerer , D. Adén

Previous calculations of the rates and optical depths due to microlensing only considered resolved stars. However, if a faint unresolved star lens is close enough to a resolved star, the event will be seen by the microlensing experiments…

Astrophysics · Physics 2007-05-23 C. Alard

We present an analysis of the longest timescale microlensing events discovered by the MACHO Collaboration during a 7 year survey of the Galactic bulge. We find 6 events that exhibit very strong microlensing parallax signals due, in part, to…

We present an abundance analysis of six main sequence turnoff, subgiant, and giant branch stars toward the Galactic bulge that were observed with Keck/HIRES during microlensing events. This is an early look at the first detailed chemical…

Astrophysics · Physics 2009-11-07 R. M. Cavallo , K. H. Cook , D. Minniti , T. Vandehei

The chemical abundances for five metal-poor stars in and towards the Galactic bulge have been determined from H-band infrared spectroscopy taken with the RAVEN multi-object adaptive optics science demonstrator and the IRCS spectrograph at…

In this work we have assumed a Hernquist model with an inside-out formation for the Galactic bulge and, using a chemical evolution model, we were able obtain the bulge metallicity distribution function (MDF) for different radial regions.…

Astrophysics of Galaxies · Physics 2017-12-06 O. Cavichia , M. Mollá

We obtained FLAMES-GIRAFFE spectra (R=22,500) at the ESO Very Large Telescope for 650 bulge red giant branch (RGB) stars and performed spectral synthesis to measure Mg, Ca, Ti, and Si abundances. This sample is composed of 474 giant stars…

The chemical abundances measured in stars of the Galactic bulge offer an unique opportunity to test galaxy formation models as well as impose strong constraints on the history of star formation and stellar nucleosynthesis. The aims of this…

Astrophysics of Galaxies · Physics 2015-05-20 Gabriele Cescutti , Francesca Matteucci

We present the discovery and statistical analysis of $12\;660$ spotted variable stars toward and inside the Galactic bulge from over two-decade-long Optical Gravitational Lensing Experiment (OGLE) data. We devise a new method of dereddening…

We examine the most recent observational constraints arising from i) small-scale and large-scale Galactic dynamical properties, ii) star counts at faint magnitude and iii) microlensing experiments. From these constraints, we determine the…

Astrophysics · Physics 2007-05-23 D. Méra , G. Chabrier , R. Schaeffer

Considering a sample of 31 exoplanetary systems detected by gravitational microlensing, we investigate whether or not the estimated distances to these systems conform to the Galactic distribution of planets expected from models. We derive…

Earth and Planetary Astrophysics · Physics 2016-11-17 Matthew T. Penny , Calen B. Henderson , Christian Clanton

A view of the Galactic bulge by means of their globular clusters is necessary for a deep understanding of its formation and evolution. Connections between the globular cluster and field star properties in terms of kinematics, orbits,…

Solar and Stellar Astrophysics · Physics 2016-07-06 E. Bica , S. Ortolani , B. Barbuy

Manganese is mainly produced in type II SNe during explosive silicon burning, in incomplete Si-burning regions, and depends on several nucleosynthesis environment conditions, such as mass cut beween the matter ejected and falling back onto…

Astrophysics of Galaxies · Physics 2015-06-17 B. Barbuy , V. Hill , M. Zoccali , D. Minniti , A. Renzini , S. Ortolani , A. Gomez , M. Trevisan , N. Dutra

The structure, formation, and evolution of the Milky Way bulge is a matter of debate. Important diagnostics for discriminating between bulge models include alpha-abundance trends with metallicity, and spatial abundance and metallicity…

Astrophysics of Galaxies · Physics 2015-12-23 N. Ryde , M. Schultheis , V. Grieco , F. Matteucci , R. M. Rich , S. Uttenthaler

Optical integrated spectra of bulges have been obtained for 28 spiral galaxies. By applying an appropriate aperture size for each galaxy, the unavoidable contamination of disk starlight has been carefully minimized and set to $\sim$ 1/7 of…

Astrophysics · Physics 2009-10-28 P. Jablonka , P. Martin , N. Arimoto

We present a detailed study of the composition of 20 M giants in the Galactic center with 15 of them confirmed to be in the Nuclear Star Cluster. As a control sample we have also observed 7 M giants in the Milky Way Disk with similar…