Detecting dark compact objects in Gaia DR4:
A data analysis pipeline for transient astrometric lensing searches

Chen, I-Kai; Kongsore, Marius; Tilburg, Ken Van

doi:10.1088/1475-7516/2023/07/037

Cited by 5 publications

(2 citation statements)

References 144 publications

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“…This means that they will not be found using standard photometric microlensing event-finding algorithms or triggering criteria (e.g., Udalski et al 2015;Husseiniova et al 2021). Equivalent astrometric event-finding algorithms will have to be developed (e.g., Chen et al 2023) to process the GBTDS survey data to extract these events or to alert on astrometric microlensing anomalies in real time for the purpose of triggering follow-up (e.g., Hundertmark et al 2018;Hodgkin et al 2021).…”

Section: Discussionmentioning

confidence: 99%

“…In the wide lens-source separation and purely astrometric regime, Van Tilburg et al (2018) derived theoretical sets of spatially correlated astrometric observables. These lensing signals can act over many sources simultaneously (e.g., Gaudi & Bloom 2005;Di Stefano 2008), can be caused by subhalo dark matter, and are expected to be detectable by Gaia (Mishra- Sharma et al 2020;Chen et al 2023;Mondino et al 2023). Motivated by Gaia's unprecedented all-sky astrometric survey, Verma & Rentala (2023) predicted that Gaia will be sensitive to PBHs via astrometric microlensing in the range of (0.4-5 × 10 7 )M e probing to f DM ≈ 3 × 10 −4 .…”

Section: Introductionmentioning

confidence: 99%

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Astrometric Microlensing by Primordial Black Holes with the Roman Space Telescope

Fardeen,

McGill,

Perkins

et al. 2024

ApJ

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Primordial black holes (PBHs) could explain some fraction of dark matter and shed light on many areas of early-Universe physics. Despite over half a century of research interest, a PBH population has so far eluded detection. The most competitive constraints on the fraction of dark matter comprised of PBHs (f DM) in the (10−9–10)M ⊙ mass ranges come from photometric microlensing and bound f DM ≲ 10−2–10−1. With the advent of the Roman Space Telescope with its submilliarcsecond astrometric capabilities and its planned Galactic Bulge Time Domain Survey (GBTDS), detecting astrometric microlensing signatures will become routine. Compared with photometric microlensing, astrometric microlensing signals are sensitive to different lens masses–distance configurations and contain different information, making it a complimentary lensing probe. At submilliarcsecond astrometric precision, astrometric microlensing signals are typically detectable at larger lens–source separations than photometric signals, suggesting a microlensing detection channel of pure astrometric events. We use a Galactic simulation to predict the number of detectable microlensing events during the GBTDS via this pure astrometric microlensing channel. Assuming an absolute astrometric precision floor for bright stars of 0.1 mas for the GBTDS, we find that the number of detectable events peaks at ≈103 f DM for a population of 1M ⊙ PBHs and tapers to ≈10f DM and ≈100f DM at 10−4 M ⊙ and 103 M ⊙, respectively. Accounting for the distinguishability of PBHs from stellar lenses, we conclude the GBTDS will be sensitive to a PBH population at f DM down to ≈10−1–10−3 for (10−1–102)M ⊙ likely yielding novel PBH constraints.

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Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Astrometric Microlensing by Primordial Black Holes with the Roman Space Telescope

Fardeen,

McGill,

Perkins

et al. 2024

ApJ

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Primordial black holes from axion domain wall collapse

Dunsky,

Kongsore

2024

J. High Energ. Phys.

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The QCD axion can solve the Strong CP Problem and be the dark matter of our universe. If the PQ symmetry breaking scale associated with the axion is below the inflationary reheating temperature, axion strings and domain walls populate the universe. Most of these strings and walls decay away into axion dark matter, but a small subset of the walls will be self-enclosed surfaces that are not attached to any strings. These enclosed walls can collapse in on themselves, compressing a large amount of energy into a small volume and potentially forming primordial black holes (PBHs). We study the number density and dynamics of these self-enclosed walls, taking into account their size distribution, Hubble expansion, asphericities, and all stages of domain wall dynamics using a combination of semi-analytic and numerical approaches. We find that axion models with a high axion decay constant fa, such as those of interest in early matter-dominated cosmologies, yield a PBH abundance potentially observable by future gravitational lensing surveys. We note that the formalism developed here is also useful for predicting relic PBH abundances in other models that exhibit unstable domain walls.

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Astrometric weak lensing with Gaia DR3 and future catalogues: searches for dark matter substructure

Mondino,

Tsantilas,

Taki

et al. 2024

Monthly Notices of the Royal Astronomical Society

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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 Ml between 107 M⊙ and 109 M⊙ 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 fl ≳ 10−3 in the much lower mass range of 10 M⊙ ≲ Ml ≲ 3 × 103 M⊙. 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.

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Detecting dark compact objects in Gaia DR4: A data analysis pipeline for transient astrometric lensing searches

Cited by 5 publications

References 144 publications

Astrometric Microlensing by Primordial Black Holes with the Roman Space Telescope

Astrometric Microlensing by Primordial Black Holes with the Roman Space Telescope

Primordial black holes from axion domain wall collapse

Astrometric weak lensing with Gaia DR3 and future catalogues: searches for dark matter substructure

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