The polarisation signature from microlensing of circumstellar envelopes in caustic crossing events

Abstract

The high gradient of magnification across the source during both small impact parameter events and caustic crossings offers a unique opportunity for determining the surface brightness profile of the source. Furthermore, models indicate that these events can also provide an appreciable polarisation signal -- arising from differential magnification across the otherwise symmetric source. In a previous paper, polarimetric variations from point lensing of a circumstellar envelope were considered, as would be suitable for an extended envelope around a red giant. In this work we examine the polarisation in the context of caustic crossing events, the scenario which represents the most easily accessible situation for actually observing a polarisation signal in Galactic microlensing.

accepted to MNRAS

References in corpus (6)

• Probing the atmosphere of a solar-like star by galactic microlensing at high magnification
• Probing the atmosphere of the bulge G5III star OGLE-2002-BUL-069 by analysis of microlense H alpha line
• Applications of Microlensing to Stellar Astrophysics
• Spatial/Spectral Resolution of a Galactic Bulge K3 Giant Stellar Atmosphere via Gravitational Microlensing
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Cited by in corpus (8)

• Polarization in microlensing towards the Galactic bulge
• Measuring Polarization in microlensing events
• Polarization in binary microlensing events
• Polarimetric microlensing of circumstellar disks
• Exoplanetary searches with gravitational microlensing: polarization issues
• Detecting the inner regions of discs around sources of microlensing with Roman Space Telescope
• Polarization in caustic-crossing binary microlensing events
• Measuring the stellar atmosphere parameters using follow-up polarimetry microlensing observations