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相关论文: Microlensing towards different Galactic targets

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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 computed the optical depth for the different intervening populations and the number…

天体物理学 · 物理学 2007-05-23 Philippe Jetzer

Gravitational microlensing constraints on non-standard compact objects are conventionally derived assuming lenses trace the dark matter halo with velocities following a Maxwell-Boltzmann distribution centered around $10^{-3}c$. However, a…

宇宙学与河外天体物理 · 物理学 2026-05-06 Manish Tamta , Nirmal Raj , Himanshu Verma

We investigate the chances that neutron stars act as the lense in a gravitational microlensing event towards the galactic bulge or a spiral arm. The observation of neutron stars by means of gravitational microlensing would allow the…

天体物理学 · 物理学 2009-11-07 Dominik J. Schwarz , Dirk Seidel

Systematic uncertainties in the mass measurement of galaxy clusters limit the cosmological constraining power of future surveys that will detect more than $10^5$ clusters. Previously, we argued that aperture masses can be inferred more…

宇宙学与河外天体物理 · 物理学 2022-08-03 Stijn N. B. Debackere , Henk Hoekstra , Joop Schaye

Using eight dark matter haloes extracted from fully-self consistent cosmological N-body simulations, we perform microlensing experiments. A hypothetical observer is placed at a distance of 8.5 kpc from the centre of the halo measuring…

天体物理学 · 物理学 2009-11-11 Janne Holopainen , Chris Flynn , Alexander Knebe , Stuart P. Gill , Brad K. Gibson

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…

天体物理学 · 物理学 2007-05-23 A. Udalski , K. Zebrun , M. Szymanski , M. Kubiak , G. Pietrzynski , I. Soszynski , P. Wozniak

We investigate the effect of blending in future gravitational microlensing surveys by carrying out simulation of Galactic bulge microlensing events to be detected from a proposed space-based lensing survey. From this simulation, we find…

天体物理学 · 物理学 2008-11-26 Cheongho Han , Byeong-Gon Park , Ho-Il Kim , Kyongae Chang

We present a catalog of 450 high signal-to-noise microlensing events observed by the MACHO collaboration between 1993 and 1999. The events are distributed throughout our fields and, as expected, they show clear concentration toward the…

Galactic model plays an important role in the microlensing field, not only for analyses of individual events but also for statistics of the ensemble of events. However, the Galactic models used in the field varies, and some are…

星系天体物理 · 物理学 2021-02-24 Hongjing Yang , Shude Mao , Weicheng Zang , Xiangyu Zhang

We present measurements of the microlensing optical depth and event rate toward the Galactic bulge using the dataset from the 2006--2014 MOA-II survey, which covers 22 bulge fields spanning ~42 deg^2 between -5 deg < l < 10 deg and -7 deg <…

We provide a status report on our search for dark matter in our Galaxy in the form of massive compact halo objects (or Machos), using gravitational microlensing of background stars. This search uses a very large format CCD camera on the…

By monitoring a large number of stars in the Local Group galaxies, we can detect nanolensing events by sub-lunar mass compact objects (SULCOs) such as primordial black holes (PBHs) and rogue (free-floating) dwarf planets in the Milky Way…

宇宙学与河外天体物理 · 物理学 2020-05-27 Kaiki Taro Inoue

Gravitational lensing of gravitational waves provides a potential new probe of dark matter structures. In this work, we consider the microlensing effect on gravitational wave signals from black hole binaries induced by low-mass dark matter…

宇宙学与河外天体物理 · 物理学 2023-07-14 Malcolm Fairbairn , Juan Urrutia , Ville Vaskonen

We discuss whether the Gaussian is a reasonable approximation of the velocity distribution of stellar systems that are not spherically distributed. By using a non-Gaussian velocity distribution to describe the sources in the Large…

星系天体物理 · 物理学 2012-01-10 Luigi Mancini

The detection of microlensing events from stars in the Large Magellanic Cloud and in the Galactic bulge raise important constraints on the distribution of dark matter and on galactic structure, although some events may be due to a new type…

天体物理学 · 物理学 2020-11-25 David Valls-Gabaud

The EROS microlensing survey has monitored nearly 100 million stars for seven years, to search for halo brown dwarfs and compact objects in the Galactic disk. In this paper, we review the various EROS observation programs and the…

天体物理学 · 物理学 2007-05-23 R. Ansari

We build a stellar-dynamical model of the Milky Way barred bulge and disk, using a newly implemented adaptive particle method. The underlying mass model has been previously shown to match the Galactic near-infrared surface brightness as…

天体物理学 · 物理学 2009-11-10 Nicolai Bissantz , Victor P. Debattista , Ortwin Gerhard

We estimate the fraction of mass that is composed of compact objects in gravitational lens galaxies. This study is based on microlensing measurements (obtained from the literature) of a sample of 29 quasar image pairs seen through 20 lens…

宇宙学与河外天体物理 · 物理学 2014-11-20 E. Mediavilla , J. A. Munoz , E. Falco , V. Motta , E. Guerras , H. Canovas , C. Jean , A. Oscoz , A. M. Mosquera

We show that the statistical error, $\sigma_{\tau}$, in estimating the optical depth, $\tau$, due to microlensing is substantially higher than the naive Poisson estimate: $\sigma_{\tau} = \sqrt{\eta / N} \tau$, where $N$ is the number of…

天体物理学 · 物理学 2009-10-22 Cheongho Han , Andrew Gould

We present the analysis of the first two years of a search for microlensing of stars in the Small Magellanic Cloud with the EROS (Exp\'erience de Recherche d'Objets Sombres) project. A single event is detected, already present in the first…

天体物理学 · 物理学 2012-08-27 EROS Collaboration