English
Related papers

Related papers: Microlensing near macro-caustics

200 papers

The first investigations of the response of the microlensing magnification pattern (at an optical depth of order unity) to the mass function of the microlenses found that the resulting statistics depend only on the mean microlens mass <m>.…

Astrophysics · Physics 2009-10-31 J. S. B. Wyithe , E. L. Turner

Optical and X-ray observations of strongly gravitationally lensed quasars (especially when four separate images of the quasar are produced) determine not only the amount of matter in the lensing galaxy but also how much is in a smooth…

We estimate the bias on weak lensing mass measurements of shear-selected galaxy cluster samples. The mass bias is expected to be significant because constructions of cluster samples from peaks in weak lensing mass maps and measurements of…

Astrophysics of Galaxies · Physics 2020-03-25 Kai-Feng Chen , Masamune Oguri , Yen-Ting Lin , Satoshi Miyazaki

We show that quasar microlensing magnification statistics induced by a population of point microlenses distributed according to a mass-spectrum can be very well approximated by that of a single-mass, "monochromatic", population. When the…

Cosmology and Nongalactic Astrophysics · Physics 2020-12-09 A. Esteban-Gutiérrez , N. Agües-Paszkowsky , E. Mediavilla , J. Jiménez-Vicente , J. A. Muñoz , S. Heydenreich

Dark matter may be in the form of non-baryonic structures such as compact subhalos and boson stars. Structures weighing between asteroid and solar masses may be discovered via gravitational microlensing, an astronomical probe that has in…

Cosmology and Nongalactic Astrophysics · Physics 2020-04-15 Djuna Croon , David McKeen , Nirmal Raj

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

Several gravitationally lensed quasars are observed with anomalous magnifications in pairs of images that straddle a critical curve. Simple theoretical arguments suggest that the magnification of these images should be approximately…

Astrophysics · Physics 2009-11-13 Nicholas F. Bate , Rachel L. Webster , Stuart Wyithe

Over the past decade, microlensing has developed into a powerful tool to study stellar astrophysics, especially stellar atmospheres, stellar masses, and binarity. I review this progress. Stellar atmospheres can be probed whenever the source…

Astrophysics · Physics 2016-08-30 Andrew Gould

The passage of stars through the beam of a lensed quasar can induce violent fluctuations in its apparent brightness. The fluctuations observed in the Huchra lens, (2237+0305), are taken to be the first evidence of this ``microlensing''…

Astrophysics · Physics 2015-06-24 G. F. Lewis , M. J. Irwin

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…

Astrophysics · Physics 2020-11-25 David Valls-Gabaud

The observations of microlensing events in the Large Magellanic Cloud suggest that a sizable fraction ($\sim$ 50%) of the galactic halo is in the form of MACHOs (Massive Astrophysical Compact Halo Objects) with an average mass $\sim 0.27…

Astrophysics · Physics 2007-05-23 F. De Paolis , Ph. Jetzer , G. Ingrosso , M. Roncadelli

Stars in globular clusters can act either as sources for MACHOs (Massive Astrophysical Compact Halo Objects) located along the line of sight or as lenses for more distant background stars. Although the expected rate of microlensing events…

Astrophysics · Physics 2007-05-23 P. Jetzer , M. Strässle , U. Wandeler

The mm-wave continuum sources (MCS) in Ophiuchus have mutual collision rates less than their collapse rates by a factor of 10 to 100, suggesting most will form stars without further interactions. However, this ratio of rates would have…

Astrophysics · Physics 2009-11-07 Bruce G. Elmegreen , Mohsen Shadmehri

Microlensing by stars within distant galaxies acting as strong gravitational lenses of multiply-imaged quasars, provides a unique and direct measurement of the internal structure of the lensed quasar on nano-arcsecond scales. The…

Many recent observational and theoretical studies suggest that globular clusters (GCs) host compact object populations large enough to play dominant roles in their overall dynamical evolution. Yet direct detection, particularly of black…

Astrophysics of Galaxies · Physics 2022-04-13 Fulya Kıroğlu , Newlin C. Weatherford , Kyle Kremer , Claire S. Ye , Giacomo Fragione , Frederic A. Rasio

We investigate gravitational microlensing of point-like lenses surrounded by diffuse gas clouds. Besides gravitational bending, one must also consider refraction and absorption phenomena. According to the cloud density, the light curves may…

Astrophysics · Physics 2009-11-07 V. Bozza , Ph. Jetzer , L. Mancini , G. Scarpetta

Cosmic superstrings are produced towards the end of the brane inflation. If the string tension is low enough, loops tend to be relatively long-lived. The resultant string network is expected to contain many loops which are smaller than…

Astrophysics · Physics 2007-09-10 David F. Chernoff , S. -H. Henry Tye

It is shown that a significant amount of detectable gravitational microlensing events that could potentially be found by MAssively Parallel Photometry (MAPP) projects (such as the MACHO, EROS and OGLE collaborations) will occur for stars…

Astrophysics · Physics 2009-10-22 Robert J. Nemiroff

Once only accessible in nearby galaxies, we can now study individual stars across much of the observable universe aided by galaxy-cluster gravitational lenses. When a star, compact object, or multiple such objects in the foreground…

Gravitational microlensing is a new technique for studying the surfaces of distant stars. A point mass lens, usually a low-mass star from the disk, will typically resolve the surface of a red giant in the Galactic bulge, as well as amplify…

Astrophysics · Physics 2007-05-23 Dimitar D. Sasselov