Astrophysics – Page 2 – Kavli Institute Pre-Print Publications

Extracting Multimodal Learngene in CLIP: Unveiling the Multimodal Generalizable Knowledge

Posted by dbos June 20, 2025June 23, 2025Peking, This Week: Astrophysics

Kavli Affiliate: Jing Wang | First 5 Authors: Ruiming Chen, Junming Yang, Shiyu Xia, Xu Yang, Jing Wang | Summary: CLIP (Contrastive Language-Image Pre-training) has attracted widespread attention for its multimodal generalizable knowledge, which is significant for downstream tasks. However, the computational overhead of a large number of parameters and large-scale pre-training poses challenges of […]

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Disentangling Metallicity Effects in Hot Jupiter Occurrence Across Galactic Birth Radius and Phase-Space Density

Posted by dbos June 19, 2025June 23, 2025MIT, This Week: Astrophysics

Kavli Affiliate: Andrew Vanderburg | First 5 Authors: Rayna Rampalli, Melissa K. Ness, Elisabeth R. Newton, Andrew Vanderburg, Tobias Buck | Summary: We explore how the correlation between host star metallicity and giant planets shapes hot Jupiter occurrence as a function of Galactic birth radius (rbirth) and phase-space density in the Milky Way disk. Using […]

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A Bimodal Metallicity Distribution Function in the Ultra-Faint Dwarf Galaxy Reticulum II

Posted by dbos June 19, 2025June 23, 2025MIT, This Week: Astrophysics

Kavli Affiliate: Anna Frebel | First 5 Authors: Alice M. Luna, Alexander P. Ji, Anirudh Chiti, Joshua D. Simon, Daniel D. Kelson | Summary: Star formation in ultra-faint dwarf galaxies (UFDs, $M_* <10^5M_odot$) is suppressed by reionization, but may not be completely quenched. The metallicity distribution function (MDF) of stars in ultra-faint dwarf galaxies could […]

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Cosmic-ray and Interstellar Gas Properties in the Solar Neighborhood Revealed by Diffuse Gamma Rays

Posted by dbos June 19, 2025June 23, 2025Stanford, This Week: Astrophysics

Kavli Affiliate: Igor V. Moskalenko | First 5 Authors: Tsunefumi Mizuno, Katsuhiro Hayashi, Hinako Ochi, Igor V. Moskalenko, Elena Orlando | Summary: To investigate the interstellar medium (ISM) and Galactic cosmic rays (CRs) in the solar neighborhood, we analyzed ${gamma}$-ray data by Fermi Large Area Telescope (LAT) for five nearby molecular cloud regions. Our data […]

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Background Measurements and Simulations of the ComPair Balloon Flight

Posted by dbos June 18, 2025June 23, 2025Stanford, This Week: Astrophysics

Kavli Affiliate: Sven Herrmann | First 5 Authors: Zachary Metzler, Nicholas Kirschner, Lucas Smith, Nicholas Cannady, Makoto Sasaki | Summary: ComPair, a prototype of the All-sky Medium Energy Gamma-ray Observatory (AMEGO), completed a short-duration high-altitude balloon campaign on August 27, 2023 from Fort Sumner, New Mexico, USA. The goal of the balloon flight was the […]

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Observing Leptogenesis in Action with Gravitational Waves

Posted by dbos June 18, 2025June 23, 2025This Week: Astrophysics, Tokyo

Kavli Affiliate: Hitoshi Murayama | First 5 Authors: Hitoshi Murayama, Bea Noether, Jan Schütte-Engel, , | Summary: Leptogenesis is arguably the best motivated theory of baryogenesis given the discovery of finite neutrino masses, yet its experimental test is elusive given its high energy scale. We discuss gravitational waves (GWs) produced via graviton bremsstrahlung in right-handed […]

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Dense SAE Latents Are Features, Not Bugs

Posted by dbos June 18, 2025June 23, 2025MIT, This Week: Astrophysics

Kavli Affiliate: Max Tegmark | First 5 Authors: Xiaoqing Sun, Alessandro Stolfo, Joshua Engels, Ben Wu, Senthooran Rajamanoharan | Summary: Sparse autoencoders (SAEs) are designed to extract interpretable features from language models by enforcing a sparsity constraint. Ideally, training an SAE would yield latents that are both sparse and semantically meaningful. However, many SAE latents […]

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Chemical Abundances in the Metal-Poor Globular Cluster ESO 280-SC06: A Formerly Massive, Tidally Disrupted Globular Cluster

Posted by dbos June 18, 2025June 23, 2025Chicago, This Week: Astrophysics

Kavli Affiliate: Alexander P. Ji | First 5 Authors: Sam A. Usman, Alexander P. Ji, Jandrie Rodriguez, Jeffrey D. Simpson, Sarah L. Martell | Summary: We present the first high-resolution abundance study of ESO 280-SC06, one of the least luminous and most metal-poor gravitationally bound Milky Way globular clusters. Using Magellan/MIKE spectroscopy for ten stars, […]

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Proper Actions and Representation Theory

Posted by dbos June 18, 2025June 23, 2025This Week: Astrophysics, Tokyo

Kavli Affiliate: Toshiyuki Kobayashi | First 5 Authors: Toshiyuki Kobayashi, , , , | Summary: This exposition presents recent developments on proper actions, highlighting their connections to representation theory. It begins with geometric aspects, including criteria for the properness of homogeneous spaces in the setting of reductive groups. We then explore the interplay between the […]

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Procedures for Constraining Robotic Fiber Positioning for Highly Multiplexed Spectroscopic Surveys: The Case of FPS for SDSS-V

Posted by dbos June 18, 2025June 23, 2025Chicago, This Week: Astrophysics

Kavli Affiliate: Alexander Ji | First 5 Authors: Ilija Medan, Tom Dwelly, Kevin R. Covey, Eleonora Zari, Michael R. Blanton | Summary: One crucial aspect of planning any large scale astronomical survey is constructing an observing strategy that maximizes reduced data quality. This is especially important for surveys that are rather heterogeneous and broad-ranging in […]

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