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Spitzer Space Telescope Observations of the Aftermath of Microlensing Event MACHO-LMC-5

Hien Trong Nguyen·Nitya Kallivayalil·Michael Werner·Charles Alcock·Brian Patten·Daniel Stern
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Abstract

We have carried out photometry of the microlensing event MACHO-LMC-5 with Spitzer's IRAC ten years after the magnification of the LMC source star was recorded. This event is unique in the annals of gravitational microlensing: the lensing star itself has been observed using HST (once with WFPC2 and twice with ACS/HRC). Since the separation between the source and lens at the epoch of the Spitzer observations was $\sim0.24''$, the two stars cannot be resolved in the Spitzer images. However, the IRAC photometry clearly establishes that the lens is a M5 dwarf star from its infrared excess, which in turn yields a mass of $\sim0.2 M_{\odot}$. This demonstrates the potential of Spitzer to detect the lenses in other gravitational microlensing events.

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Hien Trong Nguyen, Nitya Kallivayalil, Michael Werner, Charles Alcock, Brian Patten, Daniel Stern. 2004-06-01. Spitzer Space Telescope Observations of the Aftermath of Microlensing Event MACHO-LMC-5. https://arxiv.org/abs/astro-ph/0406040

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