Can lensed stars be regarded as pointlike for microlensing by MACHOs?

Witt, Hans J.; Mao, Shude

doi:10.1086/174426

Cited by 315 publications

(342 citation statements)

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“…which agrees with the expression of Witt & Mao (1994). In principle, one could also compute the image centroid for the source including occultation (as done by Witt 1995).…”

Section: Extended Uniform Sourcesupporting

confidence: 73%

“…For a uniform source, the area can be computed by integrating over the image boundaries using Stokes' theorem (Gould & Gaucherel 1997;Dominik 1998). In the case of a point-mass lens, this integral can be solved analytically, as first shown by Witt & Mao (1994) for r l ¼ 0. For an extended source with normalized radius…”

Section: Extended Uniform Sourcementioning

confidence: 99%

“…There are several different cases to consider: (Witt & Mao 1994). 3. r s > 0, 1 > r l > 0.-Extended source, inner image may be partly occulted, outer image unocculted.…”

Section: Extended Uniform Sourcementioning

confidence: 99%

“…The expressions for l AE in each of these cases are summarized in Tables 1 and 2, where p, e, and o superscripts refer to the point-source magnification (Paczyń ski 1986), extendedsource magnification (Witt & Mao 1994), and occultedextended source magnification (below), respectively, and l ¼ jr À1 l À r l j. Each of the magnification expressions in Tables 1 and 2 is given in equations (5) and (17)- (25), with the range of the variables for which the functions apply given in the columns.…”

Section: Extended Uniform Sourcementioning

confidence: 99%

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Occultation and Microlensing

Agol

2002

ApJ

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Occultation and microlensing are different limits of the same phenomenon of one body passing in front of another body. We derive a general exact analytic expression that describes both microlensing and occultation in the case of spherical bodies with a source of uniform brightness and a nonrelativistic foreground body. We also numerically compute the case of a source with quadratic limb darkening. In the limit that the gravitational deflection angle is comparable to the angular size of the foreground body, both microlensing and occultation occur as the objects align. Such events can be used to constrain the size ratio of the lens and source stars, the limb-darkening coefficients of the source star, and the surface gravity of the lens star (if the lens and source distances are known). Application of these results to microlensing during transits in binaries and giant-star microlensing is discussed. These results unify the microlensing and occultation limits and should be useful for rapid model fitting of microlensing, eclipse, and '' micro-occultation '' events.

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“…which agrees with the expression of Witt & Mao (1994). In principle, one could also compute the image centroid for the source including occultation (as done by Witt 1995).…”

Section: Extended Uniform Sourcesupporting

confidence: 73%

Section: Extended Uniform Sourcementioning

confidence: 99%

“…There are several different cases to consider: (Witt & Mao 1994). 3. r s > 0, 1 > r l > 0.-Extended source, inner image may be partly occulted, outer image unocculted.…”

Section: Extended Uniform Sourcementioning

confidence: 99%

Section: Extended Uniform Sourcementioning

confidence: 99%

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Occultation and Microlensing

Agol

2002

ApJ

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“…This is the case of an optical system with a point-like lens and an extended circular source having radius r and constant surface brightness. The implementation uses the model proposed by Witt and Mao (Witt and Mao 1994).…”

Section: On-line and Off-line Analysismentioning

confidence: 99%