Simulation of a strategy for the pixel lensing of M87 using the Hubble Space Telescope

TL;DR

This paper proposes an optimized pixel-lensing observation strategy for M87 with HST, significantly increasing high-magnification event detection and exploring mini-halo dark matter observation possibilities.

Contribution

It introduces a new intensive observation strategy for HST that enhances detection efficiency of microlensing events in M87, supported by Monte-Carlo simulations.

Findings

High-magnification events increase by over tenfold with the new strategy.

Expected detection rate of 4.2 events per day.

Potential to observe mini-halo dark matter structures.

Abstract

In this work, we propose a new strategy for the pixel-lensing observation of M87 in the Virgo cluster using the {\it Hubble Space Telescope} (HST). In contrast to the previous observational strategy by Baltz et al., we show that a few days intensive observation with the duration of $\sim 90 $min in each HST orbit will increase the observational efficiency of the high-magnification events by more than one order of magnitude. We perform a Monte-Carlo simulation for this strategy and we show that the number of high magnification microlensing events will increase at the rate of 4.2 event per day with a typical transit time scale of 16 h. We also examine the possibility of observing mini-halo dark matter structures using pixel lensing.