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相关论文: Microlensing Optical Depth towards the Galactic Bu…

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A large number of microlensing events have been observed in the direction of the Galactic bulge, with a measured optical depth in the range 2 - 3 x 10^{-6}. It has been shown that most of these events are due to bulge stars being lensed by…

天体物理学 · 物理学 2009-10-30 Vibhat Nair , Jordi Miralda-Escude

We present detailed maps of the microlensing optical depth and event density over an area of 195 sq. deg towards the Galactic bulge. The maps are computed from synthetic stellar catalogues generated from the Besancon Galaxy Model, which…

天体物理学 · 物理学 2015-05-13 E. Kerins , A. C. Robin , D. J. Marshall

We present an re-analysis of the longest timescale gravitational microlensing event discovered to date: MACHO-99-BLG-22/OGLE-1999-BUL-32, which was discovered by both the MACHO and OGLE microlensing alert systems. Our analysis of this…

天体物理学 · 物理学 2007-05-23 D. P. Bennett , A. C. Becker , J. J. Calitz , B. R. Johnson , C. Laws , J. L. Quinn , S. H. Rhie , W. Sutherland

The MACHO Project is searching for galactic dark matter in the form of massive compact halo objects (Machos). Millions of stars in the Large Magellanic Cloud (LMC), Small Magellanic Cloud (SMC), and Galactic bulge are photometrically…

Aims. We seek to probe the Galactic bulge IMF starting from microlensing observations. Methods. We analyse the recent results of the microlensing campaigns carried out towards the Galactic bulge presented by the EROS, MACHO and OGLE…

天体物理学 · 物理学 2009-06-23 S. Calchi Novati , F. De Luca , Ph. Jetzer , L. Mancini , G. Scarpetta

The primary goal of this paper is to provide the evidence that can either prove or falsify the hypothesis that dark matter in the Galactic halo can clump into stellar-mass compact objects. If such objects existed, they would act as lenses…

Perhaps as many as 30 parallax microlensing events are known, thanks to the efforts of the MACHO, OGLE, EROS and MOA experiments monitoring the bulge. Using Galactic models, we construct mock catalogues of microlensing light curves towards…

天体物理学 · 物理学 2009-11-11 M. C. Smith , V. Belokurov , N. W. Evans , S. Mao , J. H. An

Microlensing campaigns have a long history of observations covering the Galactic bulge, where thousands of detections have been obtained, including many exoplanetary systems. The Euclid Galactic Bulge Survey represents a unique opportunity…

If the massive compact halo object (MACHO) fraction of the Galactic dark halo is f ~ 20% as suggested by some microlensing experiments, then about 1.2% of lensing events toward the Galactic bulge are due to MACHOs. For the 40% of these that…

天体物理学 · 物理学 2009-11-10 Andrew Gould

The analysis of the first two years of OGLE data revealed 9 microlensing events of the galactic bulge stars, with the characteristic time scales in the range $ 8.6 < t_0 < 62 $ days, where $ t_0 = R_E / V $. The optical depth to…

天体物理学 · 物理学 2008-12-18 B. Paczynski , K. Z. Stanek , A. Udalski , M. Szymanski , J. Kaluzny , M. Kubiak , M. Mateo , W. Krzeminski

Four microlensing collaborations are presently searching for compact matter in the Galaxy and all have detected possible candidates. Using the detection efficiencies recently published by the MACHO and OGLE collaborations, we present…

天体物理学 · 物理学 2015-06-24 Eamonn J. Kerins

We have monitored 8.6 million stars in the Large Magellanic Cloud for 1.1 years and have found 3 events consistent with gravitational microlensing. We place strong constraints on the Galactic halo content in the form of compact lensing…

In the third part of the series presenting the Optical Gravitational Lensing Experiment (OGLE) microlensing studies of the dark matter halo compact objects (MACHOs) we describe results of the OGLE-III monitoring of the Large Magellanic…

We present microlensing calculations for a Galactic model based on Han & Gould (2003), which is empirically normalised by star counts. We find good agreement between this model and data recently published by the MACHO and OGLE…

天体物理学 · 物理学 2009-11-13 Alexander Wood , Shude Mao

The nature and the location of the lenses discovered in the microlensing surveys done so far towards the LMC remain unclear. Motivated by these questions we compute the optical depth and particularly the number of expected events for…

天体物理学 · 物理学 2009-11-07 Ph. Jetzer , L. Mancini , G. Scarpetta

We completed the search for microlensing events in the zero latitude area of the Galactic bulge using the VVV Survey near-IR data obtained between 2010 and 2015. We have now a total sample of N = 630 events Using the near-IR Color-Magnitude…

星系天体物理 · 物理学 2018-09-26 María Gabriela Navarro , Dante Minniti , Rodrigo Contreras Ramos

The EROS-2 project has been designed to search for microlensing events towards any dense stellar field. The densest parts of the Galactic spiral arms have been monitored to maximize the microlensing signal expected from the stars of the…

In this fourth part of the series presenting the Optical Gravitational Lensing Experiment (OGLE) microlensing studies of the dark matter halo compact objects (MACHOs) we describe results of the OGLE-III monitoring of the Small Magellanic…

We examine the left-right asymmetry in the cleaned COBE/DIRBE near-infrared data of the inner Galaxy and show (i) that the Galactic bar is probably not seen very nearly end-on, and (ii) that even if it is, it is not highly elongated. The…

天体物理学 · 物理学 2015-06-24 N. Bissantz , P. Englmaier , J. Binney , O. Gerhard