Galaxy-cluster gravitational lenses can magnify background galaxies by a total factor of up to ∼ 50. Here we report an image of an individual star at redshift z = 1.49 (dubbed “MACS J1149 Lensed Star 1 (LS1)”) magnified by > 2000. A separate image, detected briefly 0.2600 from LS1, is likely a counterimage of the first star demagnified for multiple years by a & 3 M object in the cluster. For reasonable assumptions about the lensing system, microlensing fluctuations in the stars' light curves can yield evidence about the mass function of intracluster stars and compact objects, including binary fractions and specific stellar evolution and supernova models. Dark-matter subhalos or massive compact objects may help to account for the two images' long-term brightness ratio.
|Original language||English (US)|
|State||Published - Jun 30 2017|
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