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Here, we study the microlensing of radially pulsating stars. Discerning and characterizing the properties of distant, faint pulsating stars is achievable through high-cadence microlensing observations. Combining stellar variability period…

Solar and Stellar Astrophysics · Physics 2020-04-22 Sedighe Sajadian , Richard Ignace

The idea that dark matter can be made of intermediate-mass primordial black holes in the $10M_\odot \lesssim M \lesssim 200M_\odot$ range has recently been reconsidered, particularly in the light of the detection of gravitational waves by…

Astrophysics of Galaxies · Physics 2017-02-22 E. Mediavilla , J. JimÉnez-Vicente , J. A. MuÑoz , H. Vives-Arias , J. CalderÓn-Infante

The detection of microlensing has opened the way for the development of new methods in galactic astronomy. This series of papers investigates what microlensing can teach us about the structure and shape of the dark halo. In this paper we…

The relationship between galaxies and dark matter can be characterized by the halo mass of the central galaxy and the fraction of galaxies that are satellites. Here we present observational constraints from the SDSS on these quantities as a…

There are now 10 firm time delay measurements in gravitational lenses. The physics of time delays is well understood, and the only important variable for interpreting the time delays to determine H_0 is the mean surface mass density <k> (in…

Astrophysics · Physics 2007-05-23 C. S. Kochanek , P. L. Schechter

We show how observations of multiply-imaged quasars at high redshift can be used as a probe of dark matter clumps (subhalos with masses ~ 10^9 solar masses) within the virialized extent of more massive lensing halos. A large abundance of…

Astrophysics · Physics 2015-06-24 R. Benton Metcalf , Piero Madau

Increasing evidences suggest that the Galactic halo is lumpy on kpc scales due to the accretion of at least a dozen small galaxies (LMC/SMC, Sgr, Fornax etc.). Faint stars in such lumpy structures can significant microlense a background…

Astrophysics · Physics 2009-10-30 HongSheng Zhao

Gravitational lensing is an invaluable probe of the nature of dark matter, and the structures it forms. Lensed gravitational waves in particular allow for unparalleled sensitivity to small scale structures within the lenses, due to the…

Cosmology and Nongalactic Astrophysics · Physics 2025-10-17 Luka Vujeva , Jose María Ezquiaga , Daniel Gilman , Srashti Goyal , Miguel Zumalacárregui

A nearby star having a near-transit of a galaxy will cause a time-dependent weak lensing of the galaxy. Because the effect is small, we refer to this as weak microlensing. This could provide a useful method to weigh low-mass stars and brown…

Solar and Stellar Astrophysics · Physics 2015-05-14 Jonathan Coles , Prasenjit Saha , Hans Martin Schmid

Extreme magnifications of distant objects by factors of several thousand have recently become a reality. Small very luminous compact objects, such as supernovae (SNe), giant stars at z=1-2, Pop III stars at z>7 and even gravitational waves…

Astrophysics of Galaxies · Physics 2019-05-22 Jose M. Diego

In the cold dark matter scenario, dark matter halos are assembled hierarchically from smaller subunits. Some of these subunits are disrupted during the merging process, whereas others survive temporarily in the form of subhalos. A…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-13 E. Zackrisson , T. Riehm

Microlensing started with the seminal paper by Paczy\'nski in 1986, first with observations towards the Large Magellanic Cloud and the galactic bulge. Since then many other targets have been observed and new applications have been found. In…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-15 Philippe Jetzer

The presence of brown dwarfs in the dark galactic halo could be detected through their gravitational lensing effect and experiments under way monitor about one million stars to observe a few lensing events per year. We show that if the…

Astrophysics · Physics 2007-05-23 Paul Baillon , Alain Bouquet , Yannick Giraud-Héraud , Jean Kaplan

We investigate the feasibility of extracting the gravitational nanolensing signal due to the presence of subsolar mass halos within galaxy-sized dark matter halos. We show that subsolar mass halos in a lensing galaxy can cause strong…

Cosmology and Nongalactic Astrophysics · Physics 2011-01-27 Jacqueline Chen , Savvas M. Koushiappas

We use the non-observation of strong lensing of gravitational waves (GWs) in the first three observation runs of LIGO-Virgo detectors to constrain the fraction of dark matter in the form of compact objects in the mass range…

General Relativity and Quantum Cosmology · Physics 2024-05-28 A. Barsode , S. J. Kapadia , P. Ajith

We study different models of dark matter distribution for the halo of our galaxy. In particular, we consider Eddington and King-Michie models, which [C[C, which include anisotropy in the velocity space, and compute in a self-consistent way…

Astrophysics · Physics 2009-10-28 F. De Paolis , G. Ingrosso , Ph. Jetzer

We report the discovery of a short-duration microlensing candidate in the northern field of the POINT-AGAPE pixel lensing survey towards M31. The full-width half-maximum timescale is very short, just 1.8 days. Almost certainly, the source…

We investigate microlensing amplification of faint stars in the dense stellar cluster in the Galactic Center (GC) by the super-massive black hole (BH). Such events would appear very close to the position of the radio source SgrA*, which is…

Astrophysics · Physics 2009-10-31 Tal Alexander , Amiel Sternberg

The microlensing surveys MACHO, EROS, MOA and OGLE (hereafter called MEMO) have searched for microlensing toward the Large Magellanic Cloud for a cumulated duration of 27 years. We study the potential of joining these databases to search…

Astrophysics of Galaxies · Physics 2018-10-19 Arash Mirhosseini , Marc Moniez

In microlensing of a Galactic star by a brown dwarf or other compact object, the amplified image really consists of two unresolved images with slightly different light-travel times. The difference (of order a microsecond) is GM/c^3 times a…

Instrumentation and Methods for Astrophysics · Physics 2019-05-08 Prasenjit Saha