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相关论文: Is Galactic Structure Compatible with Microlensing…

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Using 7 years of MACHO survey data, we present a new determination of the optical depth to microlensing towards the Galactic bulge. We select the sample of 62 microlensing events (60 unique) on clump giant sources and perform a detailed…

Several recent studies show that bright, intermediate and high redshift optically and radio selected QSOs are positively correlated with nearby galaxies on a range of angular scales up to a degree. Obscuration by unevenly distributed…

天体物理学 · 物理学 2009-10-31 Liliya L. R. Williams

The Optical Gravitational Lensing Experiment (OGLE, Udalski et al.~1994a; Paczy\'nski et al.~1994b -- these proceedings; and references therein) is an extensive photometric search for the rare cases of gravitational microlensing of Galactic…

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

The optimization and interpretation of microlensing surveys depends on having an accurate model of the Milky Way. However, existing population synthesis Galactic modeling tools often perform poorly in replicating the stellar contents of the…

We estimate the optical depth to self-lensing by stars in the Galactic bulge using the HST star counts of Holtzman et al and Zoccali et al as extrapolated by Gould into the brown-dwarf and remnant regimes and deprojected along the line of…

天体物理学 · 物理学 2009-11-07 Cheongho Han , Andrew Gould

We present preliminary results of the analysis of 5 years of MACHO data on the Galactic bulge microlensing events with clump giants as sources. This class of events allows one to obtain robust conclusions because relatively bright clump…

Gravitational microlensing is currently the only technique that helps study the Galactic distribution of planets as a function of distance from the Galactic center. The Galactic location of a lens system can be uniquely determined only when…

地球与行星天体物理 · 物理学 2021-09-08 Naoki Koshimoto , David P. Bennett , Daisuke Suzuki , Ian A. Bond

The Galactic bulge and bar are critical to our understanding of the Milky Way. However, due to the lack of reliable stellar distances, the structure and kinematics of the bulge/bar beyond the Galactic center have remained largely…

Searches for gravitational microlensing events are traditionally concentrated on the central regions of the Galactic bulge but many microlensing events are expected to occur in the Galactic plane, far from the Galactic Center. Owing to the…

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…

天体物理学 · 物理学 2007-05-23 C. Alard

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…

天体物理学 · 物理学 2007-05-23 D. Méra , G. Chabrier , R. Schaeffer

If stars at the lower end of the main sequence are responsible for the microlensing events observed in the Galactic bulge, then light from the lensing star contributes to the observed brightness. The background and lensing stars generally…

天体物理学 · 物理学 2009-10-22 Marc Kamionkowski

Gas in the interstellar matter is generally organized in filamentary structures, which may be also relevant for a complementary explanation of the dark matter in the Galactic halo. We examine the possibility that such structures may act as…

天体物理学 · 物理学 2009-11-10 V. Bozza , L. Mancini

A map of the projected density of the old stellar population of the Galactic Bulge region is reconstructed using 2MASS data. By making a combination of the H and K photometric bands, it is possible to overcome the effect of reddening, and…

天体物理学 · 物理学 2009-11-07 C. Alard

Disk-halo models of the Galaxy and LMC are constructed and used to analyse the microlensing data-set. Deflectors in the LMC bar, disk and halo provide an optical depth to microlensing of $\sim 2 \times 10^{-7}$. Deflectors in the Galactic…

天体物理学 · 物理学 2016-06-08 N. W. Evans

We consider a contribution of microlensing in X-ray variability of high-redshifted QSOs. Such an effect could be caused by stellar mass objects (SMO) located in a bulge or/and in a halo of this quasar as well as at cosmological distances…

天体物理学 · 物理学 2009-11-10 A. F. Zakharov , L. C. Popovic , P. Jovanovic

We discuss the tight interconnection between microlensing optical depths, flattening of dark haloes and low-to-intermediate redshift baryonic census. By analysing plots of the microlensing optical depth as a function of galactic coordinates…

天体物理学 · 物理学 2009-10-31 Srdjan Samurovic , Milan M. Cirkovic , Vesna Milosevic-Zdjelar

Microlensing results towards the LMC strongly depend on the properties of both the luminous and the dark matter distribution in the Galaxy. The two main sources of uncertainty come from the poor knowledge of the rotation curve at large…

天体物理学 · 物理学 2007-05-23 F. De Paolis , Ph. Jetzer , G. Ingrosso

In the context of this paper, microlenses present as oblate clusters of dark matter structures called massive astrophysical compact halo object(MACHO) in the galactic halo are considered. The NFW density profile [1] is derived from the…

宇宙学与河外天体物理 · 物理学 2023-11-20 Tabib Rayed Hossain , Prabir Kumar Haldar , Mehedi Kalam