Astrometric Weak Lensing with Gaia DR3 and Future Catalogs: Searches for Dark Matter Substructure

Fuente: arXiv
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Hauptverfasser: Mondino, Cristina, Tsantilas, Andreas, Taki, Anna-Maria, Van Tilburg, Ken, Weiner, Neal
Format: Preprint
Veröffentlicht: 2023
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author Mondino, Cristina
Tsantilas, Andreas
Taki, Anna-Maria
Van Tilburg, Ken
Weiner, Neal
author_facet Mondino, Cristina
Tsantilas, Andreas
Taki, Anna-Maria
Van Tilburg, Ken
Weiner, Neal
contents Small-scale dark matter structures lighter than a billion solar masses are an important probe of primordial density fluctuations and dark matter microphysics. Due to their lack of starlight emission, their only guaranteed signatures are gravitational in nature. We report on results of a search for astrometric weak lensing by compact dark matter subhalos in the Milky Way with Gaia DR3 data. Using a matched-filter analysis to look for correlated imprints of time-domain lensing on the proper motions of background stars in the Magellanic Clouds, we exclude order-unity substructure fractions in halos with masses $M_{l}$ between $10^{7} \, M_{\odot}$ and $10^{9} \, M_{\odot}$ and sizes of one parsec or smaller. We forecast that a similar approach based on proper accelerations across the entire sky with data from Gaia DR4 may be sensitive to substructure fractions of $f_{l} \gtrsim 10^{-3}$ in the much lower mass range of $10 \, M_{\odot} \lesssim M_{l} \lesssim 3 \times 10^{3} \, M_{\odot}$. We further propose an analogous technique for stacked star-star lensing events in the regime of large impact parameters. Our first implementation is not yet sufficiently sensitive but serves as a useful diagnostic and calibration tool; future data releases should enable average stellar mass measurements using this stacking method.
format Preprint
id arxiv_https___arxiv_org_abs_2308_12330
institution arXiv
publishDate 2023
record_format arxiv
spellingShingle Astrometric Weak Lensing with Gaia DR3 and Future Catalogs: Searches for Dark Matter Substructure
Mondino, Cristina
Tsantilas, Andreas
Taki, Anna-Maria
Van Tilburg, Ken
Weiner, Neal
Cosmology and Nongalactic Astrophysics
Astrophysics of Galaxies
High Energy Physics - Phenomenology
Small-scale dark matter structures lighter than a billion solar masses are an important probe of primordial density fluctuations and dark matter microphysics. Due to their lack of starlight emission, their only guaranteed signatures are gravitational in nature. We report on results of a search for astrometric weak lensing by compact dark matter subhalos in the Milky Way with Gaia DR3 data. Using a matched-filter analysis to look for correlated imprints of time-domain lensing on the proper motions of background stars in the Magellanic Clouds, we exclude order-unity substructure fractions in halos with masses $M_{l}$ between $10^{7} \, M_{\odot}$ and $10^{9} \, M_{\odot}$ and sizes of one parsec or smaller. We forecast that a similar approach based on proper accelerations across the entire sky with data from Gaia DR4 may be sensitive to substructure fractions of $f_{l} \gtrsim 10^{-3}$ in the much lower mass range of $10 \, M_{\odot} \lesssim M_{l} \lesssim 3 \times 10^{3} \, M_{\odot}$. We further propose an analogous technique for stacked star-star lensing events in the regime of large impact parameters. Our first implementation is not yet sufficiently sensitive but serves as a useful diagnostic and calibration tool; future data releases should enable average stellar mass measurements using this stacking method.
title Astrometric Weak Lensing with Gaia DR3 and Future Catalogs: Searches for Dark Matter Substructure
topic Cosmology and Nongalactic Astrophysics
Astrophysics of Galaxies
High Energy Physics - Phenomenology
url https://arxiv.org/abs/2308.12330