A Short, Nonplanetary, Microlensing Anomaly: Observations and Light‐Curve Analysis of MACHO 99‐BLG‐47

Albrow, M. D.; An, J.; Beaulieu, J. P.; Caldwell, J. A. R.; Depoy, D. L.; Dominik, M.; Gaudi, B. Scott; Gould, Andrew; Greenhill, J.; Hill, K. M.; Kane, Stephen R.; Martin, R.; Menzies, John; Pogge, Richard W.; Pollard, K. R.; Sackett, P. D.; Sahu, Kailash C.; Vermaak, P.; Watson, R.; Williams, A.

doi:10.1086/340310

Cited by 31 publications

(36 citation statements)

References 31 publications

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“…A close binary approximates a Chang & Refsdal (1979, 1984 lens with sheer ¼ ½d=(q 1=2 þ q À1=2 ) 2 , where d is the angular separation of the two components in units of E and q is their mass ratio (Dominik 1999;Albrow et al 2002). These have caustics of full angular width 4 E , which, if traversed, would give rise to obvious deviations from a point-lens light curve.…”

Section: Limits On Close Binariesmentioning

confidence: 99%

The Mass of the MACHO‐LMC‐5 Lens Star

Gould

Bennett

Alves

2004

ApJ

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We combine the available astrometric and photometric data for the 1993 microlensing event MACHO-LMC-5 to measure the mass of the lens, M ¼ 0:097 AE 0:016 M . This is the most precise direct mass measurement of a single star other than the Sun. In principle, the measurement error could be reduced as low as 10% by improving the trigonometric parallax measurement using, for example, the Space Interferometry Mission. Further improvements might be possible by rereducing the original photometric light curve using image subtraction or by obtaining new, higher precision baseline photometry of the source. We show that the current data strongly limit scenarios in which the lens is a dark (i.e., brown dwarf ) companion to the observed M dwarf rather than being the M dwarf itself. These results set the stage for a confrontation between mass estimates of the M dwarf obtained from spectroscopic and photometric measurements and a mass measurement derived directly from the star's gravitational influence. This would be the first such confrontation for any isolated star other than the Sun.

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Section: Limits On Close Binariesmentioning

confidence: 99%

The Mass of the MACHO‐LMC‐5 Lens Star

Gould

Bennett

Alves

2004

ApJ

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“…4. If these deviations are not simply due to systematic photometric errors, they are suggestive of a parallax effect (Alcock et al 1997) and/or a close caustic approach (Albrow et al 2002).…”

Section: Pa-99-n2mentioning

confidence: 99%

The POINT-AGAPE survey: 4 high signal-to-noise microlensing candidates detected towards M 31

Paulin-Henriksson

Baillon

Bouquet

et al. 2003

A&A

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Abstract.We have carried out a survey of the Andromeda galaxy for unresolved microlensing (pixel lensing). We present a subset of four short timescale, high signal-to-noise microlensing candidates found by imposing severe selection criteria: the source flux variation exceeds the flux of an R = 21 magnitude star and the full width at half maximum timescale is less than 25 days. Remarkably, in three out of four cases, we have been able to measure or strongly constrain the Einstein crossing time of the event. One event, which lies projected on the M 31 bulge, is almost certainly due to a stellar lens in the bulge of M 31. The other three candidates can be explained either by stars in M 31 and M 32 or by MACHOs.

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“…This actually could have constituted the first detection of a planet orbiting a star other than the Sun, ahead of 51 Pegasi b [5], were there not a rather complete degeneracy in the mass ratio between the binarylens constituents. Apart from lack of constraints due to sparse sampling, the mapping between features in the light curve for binary lenses and the model parameters comes with some intrinsic ambiguities, and in particular events with less prominent features can be affected by a larger degree of ambiguities and degeneracies, some of which are however well-known [29,34,35,88,[90][91][92][93], and also involve other false positives such as source binaries.…”

Section: First Resultsmentioning

confidence: 99%

Studying planet populations by gravitational microlensing

Dominik

2010

Gen Relativ Gravit

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The 'most curious' effect of the bending of light by the gravity of stars has evolved into a successful technique unlike any other for studying planets within the Milky Way and even other galaxies. With a sensitivity to cool planets around low-mass stars even below the mass of Earth, gravitational microlensing fits in between other planet search techniques to form a complete picture of planet parameter space, which is required to understand their origin in general, that of habitable planets more particularly, and that of planet Earth especially. Current campaigns need to evolve from first detections to obtaining a sample with well-understood selection bias that allows to draw firm conclusions about the planet populations. With planetary signals being a transient phenomenon, gravitational microlensing is a driver for new technologies in scheduling and management of non-proprietary heterogeneous telescope networks, and can serve to demonstrate forefront science live to the general public.

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A Short, Nonplanetary, Microlensing Anomaly: Observations and Light‐Curve Analysis of MACHO 99‐BLG‐47

Cited by 31 publications

References 31 publications

The Mass of the MACHO‐LMC‐5 Lens Star

The Mass of the MACHO‐LMC‐5 Lens Star

The POINT-AGAPE survey: 4 high signal-to-noise microlensing candidates detected towards M 31

Studying planet populations by gravitational microlensing

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