Real-time difference imaging analysis of MOA Galactic bulge observations during 2000

Abstract

A B S T R A C TWe describe observations carried out by the MOA group of the Galactic bulge during 2000 that were designed to detect efficiently gravitational microlensing of faint stars in which the magnification is high and/or of short duration. These events are particularly useful for studies of extrasolar planets and faint stars. Approximately 17 deg 2 were monitored at a sampling rate of up to six times per night. The images were analysed in real time using a difference imaging technique. 20 microlensing candidates were detected, of which eight were alerted to the microlensing community whilst in progress. Approximately half of the candidates had high magnifications (*10), at least one had very high magnification (*50), and one exhibited a clear parallax effect. The details of these events are reported here, together with details of the on-line difference imaging technique. Some nova-like events were also observed and these are described, together with one asteroid.

Reanalyses of Anomalous Gravitational Microlensing Events in the Ogle-Iii Early Warning System Database With Combined Data

“…Except for the event OGLE-2007-BLG-491, we use extra data in addition to the data from the OGLE survey. These additional data were taken from the survey conducted by the Microlensing Observations in Astrophysics (MOA: Bond et al 2001;Sumi et al 2003) group and the follow-up observation conducted by the Microlensing Follow-up Network (μFUN: Gould et al 2006), Probing Lensing Anomalies NETwork (PLANET: Beaulieu et al 2006), and RoboNet (Tsapras et al 2009). We note that the OGLE data used in the OGLE Anomaly Catalog were based on the online data processed by automatic pipeline.…”

List of Figures. List of Tables

“…Three groups are observing microlensing events when alerted by the survey groups: GMAN (Pratt et al, 1995), MPS (Rhie et al, 2000), and PLANET (Albrow et al, 2000). MOA (Bond et al, 2001) is focused to detect planets using microlensing. In the future astrometric microlensing experiments measuring the change of the center of light of the unresolvable image pair are planned using astrometric satellites like FAME, GAIA, and SIM 45 .…”

Detection of Variable Stars in the Open Cluster M11 Using Difference Image Analysis Pipeline

“…Taking advantage of this, the DIA is frequently used in the variable star detection in dense region through time series analysis. It shows an excellent result as it is also applied to the large data processing of the recent microlensing experiments by optical gravitational lensing experiment (OGLE; Udalski 2003) and microlensing observations in astrophysics (MOA; Bond et al 2001) research groups. One of the significant elements of the DIA is to calculate the kernel between the reference image and the observed image rapidly and accurately.…”