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In the era of large language models, model merging is a promising way to combine multiple task-specific models into a single multitask model without extra training. However, two challenges remain: (a) interference between different models…

Computation and Language · Computer Science 2024-10-15 Zhenyi Lu , Chenghao Fan , Wei Wei , Xiaoye Qu , Dangyang Chen , Yu Cheng

We present a machine learning (ML) approach for the prediction of galaxies' dark matter halo masses that achieves an improved performance over conventional methods. We train three ML algorithms (\texttt{XGBoost}, Random Forests, and neural…

Astrophysics of Galaxies · Physics 2019-10-16 Victor F. Calderon , Andreas A. Berlind

Estimates of galaxy merger rates based on counts of close pairs typically assume that most of the observed systems will merge within a few hundred Myr (for projected pair separations <25 kpc/h). Here we investigate these assumptions using…

Astrophysics · Physics 2009-11-13 Manfred G. Kitzbichler , Simon D. M. White

We present a dataset built for machine learning applications consisting of galaxy photometry, images, spectroscopic redshifts, and structural properties. This dataset comprises 286,401 galaxy images and photometry from the Hyper-Suprime-Cam…

Cosmology and Nongalactic Astrophysics · Physics 2024-10-02 Tuan Do , Bernie Boscoe , Evan Jones , Yun Qi Li , Kevin Alfaro

We study dynamical mass measurements of galaxy clusters contaminated by interlopers and show that a modern machine learning (ML) algorithm can predict masses by better than a factor of two compared to a standard scaling relation approach.…

Cosmology and Nongalactic Astrophysics · Physics 2016-11-09 M. Ntampaka , H. Trac , D. J. Sutherland , S. Fromenteau , B. Poczos , J. Schneider

The observation of our home galaxy, the Milky Way (MW), is made difficult by our internal viewpoint. The Gaia survey that contains around 1.6 billion star distances is the new flagship of MW structure and can be combined with other…

Astrophysics of Galaxies · Physics 2020-12-15 David Cornu

Due to an exponential increase in the number of cyber-attacks, the need for improved Intrusion Detection Systems (IDS) is apparent than ever. In this regard, Machine Learning (ML) techniques are playing a pivotal role in the early…

Cryptography and Security · Computer Science 2021-05-31 Kathryn-Ann Tait , Jan Sher Khan , Fehaid Alqahtani , Awais Aziz Shah , Fadia Ali Khan , Mujeeb Ur Rehman , Wadii Boulila , Jawad Ahmad

Model merging is an effective strategy to merge multiple models for enhancing model performances, and more efficient than ensemble learning as it will not introduce extra computation into inference. However, limited research explores if the…

Computer Vision and Pattern Recognition · Computer Science 2025-05-19 Hu Wang , Ibrahim Almakky , Congbo Ma , Numan Saeed , Mohammad Yaqub

We use stripped-down versions of three semi-analytic galaxy formation models to study the influence of different assumptions about gas cooling and galaxy mergers. By running the three models on identical sets of merger trees extracted from…

Cosmology and Nongalactic Astrophysics · Physics 2011-09-07 Gabriella De Lucia , Michael Boylan-Kolchin , Andrew J. Benson , Fabio Fontanot , Pierluigi Monaco

We investigate machine learning (ML) techniques for predicting the number of galaxies (N_gal) that occupy a halo, given the halo's properties. These types of mappings are crucial for constructing the mock galaxy catalogs necessary for…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-15 Xiaoying Xu , Shirley Ho , Hy Trac , Jeff Schneider , Barnabas Poczos , Michelle Ntampaka

We explore three different methods based on weak lensing to extract cosmological constraints from the large-scale structure. In the first approach (method I), small-scale galaxy lensing measurements of their halo mass provide a constraint…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-05 Jaiyul Yoo , Uros Seljak

The Canada-France Imaging Survey (CFIS) will consist of deep, high-resolution r-band imaging over ~5000 square degrees of the sky, representing a first-rate opportunity to identify recently-merged galaxies. Due to the large number of…

This paper presents direct evidence for hierarchical galaxy assembly out to redshifts z ~ 3. We identify major mergers using the model-independent CAS (concentration, asymmetry, clumpiness) physical morphological system on galaxies…

Weak gravitational lensing is a powerful probe for constraining cosmological parameters, but its success relies on accurate shear measurements. In this paper, we use image simulations to investigate how a joint analysis of high-resolution…

Cosmology and Nongalactic Astrophysics · Physics 2025-10-22 Shiyang Zhang , Shun-Sheng Li , Henk Hoekstra

We develop a galaxy assignment scheme that populates dark matter halos with galaxies by tracing the most bound member particles (MBPs) of simulated halos. Several merger-timescale models based on analytic calculations and numerical…

Astrophysics of Galaxies · Physics 2016-08-11 Sungwook E. Hong , Changbom Park , Juhan Kim

Modern cosmological hydrodynamical galaxy simulations provide tens of thousands of reasonably realistic synthetic galaxies across cosmic time. However, quantitatively assessing the level of realism of simulated universes in comparison to…

Non-parametric morphology measures are a powerful tool for identifying galaxy mergers at low redshifts. We employ cosmological zoom simulations using Gizmo with the Mufasa feedback scheme, post-processed using 3D dust radiative transfer…

Astrophysics of Galaxies · Physics 2018-03-08 Matthew W. Abruzzo , Desika Narayanan , Romeel Davé , Robert Thompson

We present a deep machine learning (ML)-based technique for accurately determining $\sigma_8$ and $\Omega_m$ from mock 3D galaxy surveys. The mock surveys are built from the AbacusCosmos suite of $N$-body simulations, which comprises 40…

Cosmology and Nongalactic Astrophysics · Physics 2020-02-12 Michelle Ntampaka , Daniel J. Eisenstein , Sihan Yuan , Lehman H. Garrison

Model merging and task arithmetic have emerged as promising scalable approaches to merge multiple single-task checkpoints to one multi-task model, but their applicability is reduced by significant performance loss. Previous works have…

Machine Learning · Computer Science 2024-05-14 Ke Wang , Nikolaos Dimitriadis , Guillermo Ortiz-Jimenez , François Fleuret , Pascal Frossard

Membership analysis is an important tool for studying star clusters. There are various approaches to membership determination, including supervised and unsupervised machine learning (ML) methods. We perform membership analysis using the…

Astrophysics of Galaxies · Physics 2024-09-25 A. Bissekenov , M. Kalambay , E. Abdikamalov , X. Pang , P. Berczik , B. Shukirgaliyev
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