Detecting Luminous Gravitational Microlenses Using Spectroscopy

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dc.creatorMao, S.
dc.creatorReetz, J.
dc.creatorLennon, D. L.
dc.date1998-06-17
dc.date.accessioned2026-07-07T02:27:13Z
dc.date.available2026-07-07T02:27:13Z
dc.descriptionWe propose a new method to detect the gravitational lenses in the ongoing microlensing experiments using medium and high resolution spectroscopy (resolution > 6000). Since the radial velocity of the lens and lensed source typically differs by ~100km/s, the spectral lines from the lens and source will be shifted relative to each other by (1-2)A in the optical. We simulate realistic composite spectra assuming different spectral types for the lens and source and study the lens detectability as a function of the signal-to-noise ratio, spectral resolution and lens-to-source light ratio. We show that it is possible to measure the difference in radial velocity from an unequivocal signature in the difference of cross- and auto-correlation functions calculated from two spectra obtained at different magnifications. If the lens is brighter than 10% of the unmagnified source we find that a spectral resolution of ~6000 and a signal-to-noise of 50 (at magnification maximum) are sufficient to determine the relative radial velocity of the lens. At resolution ~40000, the spectral resolution of high resolution spectrographs of 8-10m class telescopes, the lens could even be detected at a brightness of ~3% of the source. Radial velocities higher than 50km/s can be measured with an accuracy of a few km/s. Practical difficulties and observation strategies are also discussed.
dc.description11 pages, 3 figures, A&A, in press
dc.identifierhttps://arxiv.org/abs/astro-ph/9806231
dc.identifierhttp://arxiv.org/abs/astro-ph/9806231
dc.identifier.urihttp://salesiana.dossiersoluciones.com/handle/123456789/12601
dc.subjectAstrophysics
dc.titleDetecting Luminous Gravitational Microlenses Using Spectroscopy
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