Tootfinder

An interview with Gaia Marcus, director of the UK-based think tank Ada Lovelace Institute, on AI regulation in the UK and Europe, AI safety, bias, and more (Melissa Heikkilä/Financial Times)

Ada Lovelace Institute’s Gaia Marcus: regulation would increase people’s comfort with AI
The head of the UK-based think-tank talks about her hopes and fears for future oversight of AI

No certainty of a Milky Way–#Andromeda collision: https://www.nature.com/articles/s41550-025-02563-1 -> Hubble and Gaia revisit fate of our galaxy: https://www.esa.int/Science_Exploration/Space_Science/Hubble_and_Gaia_revisit_fate_of_our_galaxy / Apocalypse When? Hubble Casts Doubt on Certainty of Galactic Collision: https://science.nasa.gov/missions/hubble/apocalypse-when-hubble-casts-doubt-on-certainty-of-galactic-collision/

Evidence of Gaia Enceladus experiencing at least two passages around the Milky Way
\'Asa Sk\'ulad\'ottir, Heitor Ernandes, Diane K. Feuillet, Alice Mori, Sofia Feltzing, Romain E. R. Lucchesi, Paola Di Matteo
https://arxiv.org/abs/2506.00409

Evidence of Gaia Enceladus experiencing at least two passages around the Milky Way
One of the major recent breakthroughs has been the discovery of the last Major Merger to happen in the history of the Milky Way. Around 10 Gyr ago the galaxy Gaia Enceladus, with estimated ~10% of the Milky Way mass, fell into its potential, bringing a large amount of stars which can be identified through their unique chemical and kinematic signatures. Simulations have long predicted that a galaxy of this size should experience several passages through the disk of the Milky Way before eventuall…

This https://arxiv.org/abs/2503.04672 has been replaced.
initial toot: https://mastoxiv.page/@arXiv_…

Finding White Dwarfs' Hidden Companions using an Unsupervised Machine Learning Technique
White dwarfs (WD) with main-sequence (MS) companions are crucial probes of stellar evolution. However, due to the significant difference in their luminosities, the WD is often outshined by the MS star. The aim of this work is to find hidden companions in Gaia's sample of WD candidates. Our methodology involves applying an unsupervised machine learning algorithm for dimensionality reduction and clustering, known as Self-Organizing Map (SOM), to Gaia BP/RP (XP) spectra. This strategy allows us to…

This https://arxiv.org/abs/2505.22205 has been replaced.
initial toot: https://mastoxiv.page/@arXiv_…

The Gaia spectroscopic catalogue of exoplanets and host stars
Complete, accurate, and precise catalogues of exoplanet host star (EHS) properties are essential to deriving high-quality exoplanet parameters. This paper aims at homogeneously parameterising EHS and their exoplanets, using Gaia and GSP-spec data. For 2573 EHS, we computed their L*, R*, and M*, with no prior assumption from stellar evolution models. Their Galactic positions, kinematic and orbital properties were derived. We re-scaled Mp and Rp of 3556 exoplanets, fully consistently with the ste…

Local dark matter density from Gaia DR3 K-dwarfs using Gaussian processes
Laurin S\"oding, Ruben Bartel, Philipp Mertsch
https://arxiv.org/abs/2506.02956

Local dark matter density from Gaia DR3 K-dwarfs using Gaussian processes
Modern astrophysical surveys have produced a wealth of data on the positions and velocities of stars in the Milky Way with varying accuracies. An ever-increasing detail in observational data calls for more complex physical models and in turn more sophisticated statistical methods to extract information. We perform a vertical Jeans analysis, including a local approximation of the tilt term, using a sample of $200\,000$ K-dwarf stars from the Gaia DR3 catalogue. After combination with the Survey-…

This https://arxiv.org/abs/2412.14844 has been replaced.
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Astrometry-Only Detection of Microlensing Events with Gaia
Astrometric microlensing events occur when a massive object passes between a distant source and the observer, causing a shift of the light centroid. The precise astrometric measurements of the Gaia mission provide an unprecedented opportunity to detect and analyze these events, revealing properties of lensing objects such as their mass and distance. We develop and test the Gaia Astrometric Microlensing Events (GAME) Filter, a software tool to identify astrometric microlensing events and derive …

Main belt asteroid mass estimation from high-precision astrometry: #Asteroid Masses: https://eos.org/articles/the-late-great-gaia-helps-reveal-asteroid-masses - astronomers are using data from the recently decommissioned star-mapping satellite to help determine masses and more accurate orbits of celestial bodies closer to home.

Eighteen Exoplanet Host Stars from the NPOI Data Archive
Ellyn K. Baines, Jeremy Jones, James H. Clark III, Henrique R. Schmitt, Jordan M. Stone
https://arxiv.org/abs/2506.02934

Eighteen Exoplanet Host Stars from the NPOI Data Archive
During the course of publishing angular diameters from the Navy Precision Optical Interferometer data archive, we found we had data on 17 confirmed exoplanet host stars and one exoplanet candidate (HD 20902/alpha Per). Here, we update our previously published stellar radii with more precise Gaia parallaxes when available, and use our radius and effective temperature measurements to fit each star's mass and age using MIST models. The mass changed by more than 10% for 9 of the 18 stars. Combining…

This https://arxiv.org/abs/2505.18378 has been replaced.
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Metallicities of old open clusters: a new Galactic map
Old open clusters can constrain the chemical evolution of the Galactic disc through their metallicity gradients and age-metallicity relation but they suffer from low statistics. This work aims to determine precise and homogeneous metallicities for a number of old ($\geq$ 500 Myr) clusters from all-sky catalogues of stellar parameters leveraging Gaia spectrophotometry. Our purpose was to revisit the metallicity distribution of the oldest open clusters as a function of their Galactic position and…

This https://arxiv.org/abs/2412.13727 has been replaced.
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Open Superclusters II. Discovery of an Inactive Supercluster Including a New Star Cluster in the Solar Neighborhood
The number of known star clusters, associations, and moving groups in the vicinity of the Sun has increased significantly due to the use of Gaia data. We investigated the existence and properties of open superclusters (OSC) within 500 pc of the Sun, with a particular focus on a newly identified OSC, designated HC8. Using advanced Gaia-derived astrometric data and star cluster catalogs, we identify and analyze member stars of various clusters, deriving key parameters such as ages, distances, ext…

The Gaia spectroscopic catalogue of exoplanets and host stars
Patrick de Laverny, Roxanne Ligi, Aur\'elien Crida, Alejandra Recio-Blanco, Pedro A. Palicio
https://arxiv.org/abs/2505.22205

The Gaia spectroscopic catalogue of exoplanets and host stars
Complete, accurate, and precise catalogues of exoplanet host star (EHS) properties are essential to deriving high-quality exoplanet parameters. This paper aims at homogeneously parameterising EHS and their exoplanets, using Gaia and GSP-spec data. For 2573 EHS, we computed their L*, R*, and M*, with no prior assumption from stellar evolution models. Their Galactic positions, kinematic and orbital properties were derived. We re-scaled Mp and Rp of 3556 exoplanets, fully consistently with the ste…

Hydrodynamic simulations of black hole evolution in AGN discs I: orbital alignment of highly inclined satellites
Connar Rowan, Henry Whitehead, Gaia Fabj, Philip Kirkeberg, Martin E. Pessah, Bence Kocsis
https://arxiv.org/abs/2505.23739

Hydrodynamic simulations of black hole evolution in AGN discs I: orbital alignment of highly inclined satellites
The frequency of compact object interactions in AGN discs is naturally tied to the number of objects embedded within it. We investigate the evolution of black holes in the nuclear stellar cluster on inclined orbits to the AGN disc by performing adiabatic hydrodynamical simulations of isolated black hole disc crossings over a range of disc densities and inclinations $i\in[2^\circ,15^\circ]$. We find radiation dominates the pressure in the wake that forms around the BH across the full inclination…

The chemical and spatial variations of the bulge's velocity ellipsoids
Luis M. San Martin Fernandez, Steven Gough-Kelly, Victor P. Debattista, Oscar A. Gonzalez, Ilin Lazar, Alvaro Rojas-Arriagada, Leandro Beraldo e Silva
https://arxiv.org/abs/2506.02876

The chemical and spatial variations of the bulge's velocity ellipsoids
We study the velocity ellipsoids in an $N$-body$+$SPH simulation of a barred galaxy which forms a bar with a BP bulge. We focus on the 2D kinematics, and quantify the velocity ellipses by the anisotropy, $β_{ij}$, the correlation, $ρ_{ij}$, and the vertex deviation, $l_{\rm v}$. We explore the variations in these quantities based on stellar age within the bulge and compare these results with the Milky Way's bulge using data from APOGEE DR16 and {\it Gaia} DR3. We first explore the variation o…

This https://arxiv.org/abs/2410.17312 has been replaced.
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Chemical Abundances in the Leiptr Stellar Stream: A Disrupted Ultra-faint Dwarf Galaxy?
Chemical abundances of stellar streams can be used to determine the nature of a stream's progenitor. Here we study the progenitor of the recently discovered Leiptr stellar stream, which was previously suggested to be a tidally disrupted halo globular cluster. We obtain high-resolution spectra of five red giant branch stars selected from the Gaia DR2 STREAMFINDER catalog with Magellan/MIKE. One star is a clear non-member. The remaining four stars display chemical abundances consistent with those…

Pan-tropical plant functional trait variation from space
David Schimel, Andres Baresch, Adam Chlus, Phil Townsend, Fabian Schneider, Gaia Vaglio Laurin, Ben Poulter
https://arxiv.org/abs/2505.19199

Pan-tropical plant functional trait variation from space
Plant functional trait variation in tropical forests is central to predicting ecosystem responses to change. Informaiton on traits is limited relative to the diversity of climate, landforms, disturbance regimes and species present. These traits are central to modeled predictions of ecosystem change. We used a new spaceborne imagining spectrometer from the Italian Space Agency to sample roughly 1% of the tropical moist forest biome for traits along the Leaf Economics Spectrum, as well as data to…

The stellar population in the SARAO MeerKAT Galactic Plane Survey
Okwudili D. Egbo, David A. H. Buckley, Paul J. Groot, Francesco Cavallaro, Patrick A. Woudt, Mark A. Thompson, Mubela Mutale, Michael Bietenholz
https://arxiv.org/abs/2505.22139

The stellar population in the SARAO MeerKAT Galactic Plane Survey
We report on optically selected stellar candidates of SARAO MeerKAT 1.3 GHz radio continuum survey sources of the Galactic plane. Stellar counterparts to radio sources are selected by cross-matching the MeerKAT source positions with \textit{Gaia} DR3, using two approaches. The first approach evaluated the probability of chance alignments between the radio survey and \textit{Gaia} sources and used AllWISE infrared colour-colour information to select potential stellar candidates. The second appro…