Title:	Microlensing light curves of stars in M31
DNr:	SNIC 2019/3-575
Project Type:	SNIC Medium Compute
Principal Investigator:	Ariel Goobar <ariel@fysik.su.se>
Affiliation:	Stockholms universitet
Duration:	2019-11-01 – 2020-02-01
Classification:	10305
Keywords:

Abstract

While cosmological observations are well explained by a concordance Lambda CDM model, the physical nature of the most abundant components dark energy and dark matter remain unknown. Of different origins theorized for dark matter, a few of them (for eg. Primordial Black Holes, relics of phase transitions) would comprise of relatively compact massive objects while others (for eg. WIMPS and BEC) would comprise of diffused distributions (halos) of low mass particles. If a fraction of the dark matter density was due to compact objects, stars in nearby galaxies such as the Andromeda (M31) could be statistically micro-lensed by intervening compact objects. The Zwicky Transient Facility (ZTF) is an ongoing time-domain astronomical survey with public and private data [1], with a large fraction of the images being processed at IPAC. We would like to search for signatures of microlensed stars in the M31 in this dataset. Since the standard processing of image subtraction provided by IPAC is challenging in crowded stellar fields like the Andromeda (M31), and not required for our goal, we wish to process these images differently. We use the pixels on the ZTF images to obtain time series of brightnesses at the location of stars in the M31 recorded in the publicly available dataset of resolved stars (but with no time sampling) from The Panchromatic Hubble Andromeda Treasury (PHAT) survey[2]. We are using our own code based on public packages in python. [1] The Zwicky Transient Facility: System Overview, Performance, and First Results, Bellm et al. 2019. [2] https://archive.stsci.edu/prepds/phat/