Prospects of cosmic superstring detection through microlensing of extragalactic point-like sources

• The existence of cosmic superstrings may be probed by astronomical time domain surveys. When crossing the line of sight to point-like sources, strings produce a distinctivemicrolensing signature. We consider two avenues to hunt for a relic population of superstring loops: frequent monitoring of (1) stars in Andromeda, lensed by loops in the haloes of the Milky-Way and Andromeda and (2) supernovae at cosmological distances, lensed by loops in the intergalactic medium. We assess the potential of such experiments to detect and/or constrain strings with a range of tensions, 10(-15) less than or similar to G mu/c(2) less than or similar to 10(-6). The practical sensitivity is tied to cadence of observations which we explore in detail. We forecast that high-cadence monitoring of similar to 10(5) stars on the far side of Andromeda over a year-long period will detect microlensing events if G mu/c(2) similar to 10(-13), while similar to 10(6) stars will detect events if 10(-13.5) < G mu/c(2) < 10(-11.5); the upper and lower bounds of the accessible tension range continue to expand as the number of stars rises. We also analyse the ability to reject models in the absence of fluctuations. While challenging, these studies are within reach of forthcoming time-domain surveys. Supernova observations can hypothetically constrain models with 10(-12) < G mu/c(2) < 10(-6) without any optimization of the survey cadence. However, the event rate forecast suggests it will be difficult to reject models of interest. As a demonstration, we use observations from the Pantheon Type Ia supernova cosmology data set to place modest constraints on the number density of cosmic superstrings in a poorly tested region of the parameter space.

Ämnesord

NATURVETENSKAP  -- Fysik -- Astronomi, astrofysik och kosmologi (hsv//swe)

NATURAL SCIENCES  -- Physical Sciences -- Astronomy, Astrophysics and Cosmology (hsv//eng)

Nyckelord

gravitational lensing: micro

methods: observational

supernovae: general

cosmology: theory

Theoretical Physics

teoretisk fysik

Publikations- och innehållstyp

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