[{"id":20,"title":"The Galactic Astigmatism: Constraining the Milky Way Dark Matter Halo Using Ultra-Weak Lensing","sha":"86fd4606f693acf5f94c2808e69804d1","user_id":14,"state":"published","body":"An astigmatism is defined as an asymmetry of the front of the eye, causing light to not focus on a single point. Because the Sun is located ~8kpc off-center in the Milky Way, the integrated mass density of galactic dark matter varies significantly along different lines of sight. As a result, the Milky Way's own DM halo will act as a gravitational lens, magnifying background sources more along lines of sight toward the bulge, and less towards the anti-center. While such lensing may be very weak, it is decidedly non-zero. This ultra-weak lensing may be detected in the number density or apparent brightness of (for example) distant galaxies.\r\n\r\nI note also, this effect has been mentioned only once in the literature that I am aware of, by [Xu and Wu (1987)](http://adsabs.harvard.edu/abs/1987IAUS..124..771X), who speculate the brightness amplification signal may as large as 1e-6 to 1e-5, and possibly detectable in precision CMB data.","created_at":"2015-02-04T22:08:51.143Z","updated_at":"2018-02-19T06:00:28.098Z","zenodo_id":21481,"doi":"http://dx.doi.org/10.5281/zenodo.14841","subject":null,"tags":["astronomy","galaxies","darkmatter","speculation"],"vote_count":13,"view_count":1,"score":13.1,"deleted":false,"muted":false,"tweeted":true,"attachment_file_name":null,"attachment_content_type":null,"attachment_file_size":null,"attachment_updated_at":null}]