The Power of Halometry

Code repository for the paper The Power of Halometry by Siddharth Mishra-Sharma, Ken Van Tilburg, and Neal Weiner.

A highly exaggerated illustration of induced astrometric lensing effects. The red arrows indicate the instantaneous induced velocity due to the two moving lenses, with arrow length proportional to the magnitude. Produced in this notebook.

Abstract

Astrometric weak gravitational lensing is a potentially powerful probe of the distribution of matter on sub-Galactic scales, which harbor important information about the fundamental nature of dark matter. We propose a novel method that utilizes angular power spectra to search for the correlated pattern of apparent motions of celestial objects induced from time-dependent lensing by a population of Galactic subhalos. Application of this method to upcoming astrometric datasets will allow for the direct measurement of the properties of Galactic substructure with implications for the underlying particle physics. We show that, with near-future astrometric observations, it may be possible to statistically detect populations of cold dark matter subhalos, compact objects, as well as density fluctuations sourced by scalar field dark matter. Additionally, currently-unconstrained parameter space characterizing enhanced primordial fluctuations on small scales will already be accessible using upcoming data from the ongoing Gaia mission.

Code

The dependencies of the code are listed in environments.yml.

The notebooks folder contains various Jupyter notebooks that reproduce the plots in the paper. These are linked to from the paper.

Authors

• Siddharth Mishra-Sharma; sm8383 at nyu dot edu
• Ken Van Tilburg; kvt at kitp dot ucsb dot edu
• Neal Weiner; neal dot weiner at nyu dot edu

Citation

If you use this code, please cite our paper:

@article{Mishra-Sharma:2020ynk,
    author = "Mishra-Sharma, Siddharth and Van Tilburg, Ken and Weiner, Neal",
    title = "{The Power of Halometry}",
    eprint = "2003.02264",
    archivePrefix = "arXiv",
    primaryClass = "astro-ph.CO",
    doi = "10.1103/PhysRevD.102.023026",
    journal = "Phys. Rev. D",
    volume = "102",
    number = "2",
    pages = "023026",
    year = "2020"
}