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相关论文: A Puzzle Involving Galactic Bulge Microlensing Eve…

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This paper investigates the peculiar behaviour of the light even (alpha-elements) and odd atomic number elements in red giants in the galactic bulge, both in terms of the chemical evolution of the bulge, and in terms of possible deep-mixing…

天体物理学 · 物理学 2009-11-11 A. Lecureur , V. Hill , M. Zoccali , B. Barbuy , A. Gomez , D. Minniti , S. Ortolani , A. Renzini

Finite source effects can be important in observations of gravitational microlensing of stars. Near caustic crossings, for example, some parts of the source star will be more highly magnified than other parts. The spectrum of the star is…

星系天体物理 · 物理学 2014-11-20 Jennifer A. Johnson , Subo Dong , Andrew Gould

We present wide field JHKs photometry of 16 Galactic globular clusters located towards the Galactic bulge, calibrated on the 2MASS photometric system. Differential reddening corrections and statistical field star decontamination are…

太阳与恒星天体物理 · 物理学 2016-11-15 Roger E. Cohen , Christian Moni Bidin , Francesco Mauro , Charles Bonatto , Douglas Geisler

This work explores the detailed chemistry of the Milky Way bulge using the HERMES spectrograph on the Anglo-Australian Telescope. Here we present the abundance ratios of 13 elements for 832 red giant branch and clump stars along the minor…

星系天体物理 · 物理学 2019-05-08 L. Duong , M. Asplund , D. M. Nataf , K. C. Freeman , M. Ness

The Galactic bulge has a bimodal metallicity distribution function: different kinematic, spatial, and, potentially, age distributions characterize the metal-poor and metal-rich components. Despite this observed dichotomy, which argues for…

星系天体物理 · 物理学 2019-05-07 A. Rojas-Arriagada , M. Zoccali , M. Schultheis , A. Recio-Blanco , G. Zasowski , D. Minniti , H. Jönsson , R. E. Cohen

We present the analysis of the radial gradients of stellar absorption lines in a sample of 32 bulges of edge-on spiral galaxies, spanning nearly the full Hubble sequence (from S0 to Sc types), and a large range of velocity dispersion (from…

天体物理学 · 物理学 2009-11-13 P. Jablonka , J. Gorgas , P. Goudfrooij

We present evidence for a strong correlation between the concentration of bulges and the mass of their central supermassive black hole (M_bh) -- more concentrated bulges have more massive black holes. Using C_{r_e}(1/3) from Trujillo,…

天体物理学 · 物理学 2009-11-07 Alister W. Graham , Peter Erwin , Nicola Caon , Ignacio Trujillo

We propose a new method that can be used to constrain the properties of the Galactic bar (bulge). If the majority of the lensing objects are in the Galactic bar, then we predict a systematic offset in the apparent magnitude between lensed…

天体物理学 · 物理学 2009-10-22 K. Z. Stanek

Hundreds of gravitational microlensing events have now been detected towards the Galactic bulge, with many more to come. The detection of fine structure in these events has been theorized to be an excellent way to discover extra-solar…

天体物理学 · 物理学 2010-04-06 Kim Griest , Neda Safizadeh

We present microlens parallax measurements for 21 (apparently) isolated lenses observed toward the Galactic bulge that were imaged simultaneously from Earth and Spitzer, which was ~1 AU West of Earth in projection. We combine these…

The determination of the age of the bulge has led to two contradictory results. On the one side, the color-magnitude diagrams in different bulge fields seem to indicate a uniformly old ($>$10 Gyr) population. On the other side, individual…

星系天体物理 · 物理学 2016-10-05 M. Haywood , P. Di Matteo , O. Snaith , A. Calamida

Globular cluster systems exhibit a bewildering variety of characteristics. No single scenario appears to be able to account for the wide range of specific globular cluster frequencies that are observed in galaxies of various types. The…

天体物理学 · 物理学 2009-10-31 Sidney van den Bergh

Gravitational microlensing surveys target very dense stellar fields in the local group. As a consequence the microlensed source stars are often blended with nearby unresolved stars. The presence of `blending' is a cause of major uncertainty…

天体物理学 · 物理学 2009-11-13 Martin C. Smith , Przemyslaw Wozniak , Shude Mao , Takahiro Sumi

AIMS:The aim of this paper is to study the characteristics of the stellar populations and the metallicity distribution in the Galactic bulge. We study the entire stellar population, but also retrieve information using only the red clump…

星系天体物理 · 物理学 2023-07-19 E. Vanhollebeke , M. A. T. Groenewegen , L. Girardi

New information on the relations between the Galactic disks, the halo, and satellite galaxies is being obtained from elemental abundances of stars having metallicities in the range -1.5 < [Fe/H] < -0.5. The first results for a sample of 26…

天体物理学 · 物理学 2015-05-13 Poul E. Nissen , William J. Schuster

We obtained high-resolution near-IR spectra of 45 AGB stars located in the Galactic bulge. The aim of the project is to determine key elemental abundances in these stars to help constrain the formation history of the bulge. A further aim is…

Among stars in Galactic globular clusters the carbon abundance tends to decrease with increasing luminosity on the upper red giant branch, particularly within the lowest metallicity clusters. While such a phenomena is not predicted by…

太阳与恒星天体物理 · 物理学 2019-04-08 Jeffrey M. Gerber , Michael M. Briley , Graeme H. Smith

RR Lyrae stars are excellent tracers of stellar populations for old, metal-poor components in the Milky Way Galaxy and the Local Group. Their luminosities have a metallicity-dependence, but determining spectroscopic [Fe/H] metallicities for…

The evolution of the Milky Way bulge and its relationship with the other Galactic populations is still poorly understood. The bulge has been suggested to be either a merger-driven classical bulge or the product of a dynamical instability of…

The analysis of the first three years of the OGLE data revealed 12 microlensing events of the Galactic bulge stars, with the characteristic time scales in the range $ 8.6 < t_0 < 80 $ days, where $ t_0 = R_E / V $. A complete sample of nine…

天体物理学 · 物理学 2007-05-23 B. Paczynski , K. Z. Stanek , A. Udalski , M. Szymanski , J. Kaluzny , M. Kubiak , M. Mateo , W. Krzeminski , G. W. Preston