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The VVV microlensing search has recently surveyed the region of the Galactic plane at b=0 within -10.00 < l < 10.44 deg. in the near-infrared (IR), discovering hundreds of microlensing events. In this paper we explore the microlensing…

Solar and Stellar Astrophysics · Physics 2020-10-14 Maria Gabriela Navarro , Dante Minniti , Rodrigo Contreras Ramos

We present the largest ground-based catalogue of M-dwarf flares to date, comprising 1,229 time-resolved events identified in Zwicky Transient Facility Data Release 17. Using high-cadence ZTF observations collected between April 2018 and…

Solar and Stellar Astrophysics · Physics 2026-03-04 A. D. Lavrukhina , B. Demkov , K. Malanchev , M. V. Pruzhinskaya , E. E. O. Ishida

We search for microlensing events in fields along the Galactic minor axis, ranging from the Galactic center to -3.7<b< 3.9 deg., using the VVV survey near-IR photometry. The new search is made across VVV tiles b291, b305, b319, b347, b361…

Solar and Stellar Astrophysics · Physics 2020-02-05 Maria Gabriela Navarro , Dante Minniti , Joyce Pullen , Rodrigo Contreras Ramos

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

Following the suggestion of Gould and Depoy (1998) we investigate the feasibility of studying the brightest microlensing events towards the Galactic bulge using a small aperture (~10 cm) telescope. We used one of the HAT telescopes to…

Astrophysics of Galaxies · Physics 2009-05-01 D. M. Nataf , K. Z. Stanek , G. A. Bakos

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…

Earth and Planetary Astrophysics · Physics 2021-09-08 Naoki Koshimoto , David P. Bennett , Daisuke Suzuki , Ian A. Bond

Ongoing microlensing surveys have already yielded more than five hundred microlensing events, most of which have been identified in real-time. In this review I present the basic theory and observational status of these surveys. I highlight…

Astrophysics · Physics 2007-05-23 Shude Mao

The Zwicky Transient Facility (ZTF) has been observing the entire northern sky since the start of 2018 down to a magnitude of 20.5 ($5 \sigma$ for 30s exposure) in $g$, $r$, and $i$ filters. Over the course of two years, ZTF has obtained…

The VISTA Variables in the Via Lactea (VVV) survey and its extension, have been monitoring about 560 square degrees of sky centred on the Galactic bulge and inner disc for nearly a decade. The photometric catalogue contains of order 10$^9$…

Astrophysics of Galaxies · Physics 2021-07-14 Andrea Husseiniova , Peter McGill , Leigh C. Smith , N. Wyn Evans

We determine the microlensing event rate distribution, $\Gamma(t_{E})$, that is properly normalized by the first year MACHO group observations (Alcock et al. 1997). By comparing the determined $\Gamma(t_{E})$ with various MF models of lens…

Astrophysics · Physics 2007-05-23 Cheongho Han , Seunghun Lee

We describe a real-time spectroscopic program to observe bright gravitational microlensing events toward the Galactic Bulge. The program is carried out using the NTT at ESO. We present the preliminary analysis of the microlensing events we…

Astrophysics · Physics 2007-05-23 D. Lennon , S. Mao , J. Reetz , T. Gehren , L. Yan , A. Renzini

We search for microlensing events in the highly reddened areas surrounding the Galactic center using the near-IR observations with the VISTA Variables in the V\'ia L\'actea Survey (VVV). We report the discovery of 182 new microlensing…

Solar and Stellar Astrophysics · Physics 2017-12-22 María Gabriela Navarro , Dante Minniti , Rodrigo Contreras Ramos

We analyze an ensemble of microlensing events from the 2015 Spitzer microlensing campaign, all of which were densely monitored by ground-based high-cadence survey teams. The simultaneous observations from Spitzer and the ground yield…

When planning a survey for astronomical transients, many factors such as cadence, filter choice, sky coverage, and depth of observations need to be balanced in order to optimize the scientific gain of the survey. Here we present a software…

Instrumentation and Methods for Astrophysics · Physics 2019-10-09 Ulrich Feindt , Jakob Nordin , Mickael Rigault , Valéry Brinnel , Suhail Dhawan , Ariel Goobar , Marek Kowalski

We estimate the rate of near-field microlensing events expected from all-sky surveys and investigate the properties of these events. Under the assumption that all lenses are composed of stars, our estimation of the event rate ranges from…

Astrophysics · Physics 2009-11-13 Cheongho Han

The Wide Field Infrared Survey Telescope (WFIRST) will monitor $\sim 2$ deg$^2$ toward the Galactic bulge in a wide ($\sim 1-2~\mu$m) W149 filter at 15-minute cadence with exposure times of $\sim$50s for 6 seasons of 72 days each, for a…

Optical microlensing surveys are restricted from detecting events near the Galactic plane and center, where the event rate is thought to be the highest, due to the high optical extinction of these fields. In the near-infrared (NIR),…

Earth and Planetary Astrophysics · Physics 2017-01-18 Y. Shvartzvald , G. Bryden , A. Gould , C. B. Henderson , S. B. Howell , C. Beichman

Thousands of active artificial objects are orbiting around Earth along with much more non-operational ones -- derelict satellites or rocket bodies, collision debris, or spacecraft payloads, significant part of them being uncatalogued. They…

Instrumentation and Methods for Astrophysics · Physics 2022-02-14 Sergey Karpov , Julien Peloton

A new type of gravitational microlensing experiment toward a field where stars are not resolved is being developed observationally and theoretically: pixel lensing. When the experiment is carried out toward the M31 bulge area, events may be…

Astrophysics · Physics 2009-10-28 Cheongho Han , Andrew Gould

We analyze the first-year MACHO collaboration observations of microlensing towards the Galactic center using a new direct likelihood technique that is sensitive to the distribution of the events on the sky. We consider the full set of 41…

Astrophysics · Physics 2007-05-23 Geza Gyuk