Portrait de Yashar Hezaveh

Yashar Hezaveh

Membre académique associé

Professeur adjoint, Université de Montréal, Département de physique

Biographie

Yashar Hezaveh est membre associé de Mila – Institut québécois d'intelligence artificielle et directeur de Ciela – Institut de Montréal pour l'analyse des données astrophysiques et l'apprentissage automatique. Il est professeur adjoint au Département de physique de l'Université de Montréal, titulaire d'une chaire de recherche du Canada en analyse de données astrophysiques et apprentissage automatique, membre associé de l'Institut spatial Trottier de l'Université McGill et chercheur invité au Center for Computational Astrophysics du Flatiron Institute (New York) et au Perimeter Institute. Auparavant, il a été chercheur au Flatiron Institute (2018-2019) et boursier Hubble de la NASA à l'Université de Stanford (2013-2018).

Il est un leader mondial dans l'analyse des données astrophysiques avec l'apprentissage automatique. Ses recherches actuelles portent principalement sur l'inférence bayésienne dans l'IA (par exemple, les modèles de diffusion) et visent à faire progresser les connaissances sur la distribution de la matière noire dans les galaxies fortement lenticulaires à l'aide de données provenant de grands relevés cosmologiques. Ses recherches sont soutenues par la Schmidt Futures Foundation et la Simons Foundation.

Étudiants actuels

Doctorat - Université de Montréal

Superviseur⋅e principal⋅e :

Laurence Perreault-Levasseur

andreas.filipp@mila.quebec

Antoine Bourdin

Stagiaire de recherche - McGill University

Superviseur⋅e principal⋅e :

Laurence Perreault-Levasseur

antoine.bourdin@mila.quebec

Postdoctorat - Université de Montréal

Superviseur⋅e principal⋅e :

Laurence Perreault-Levasseur

connor.stone@mila.quebec

Maîtrise recherche - McGill University

dhvani.doshi@mila.quebec

Stagiaire de recherche - Université de Montréal

Co-superviseur⋅e :

Laurence Perreault-Levasseur

etienne.collin@mila.quebec

Franco Del Balso

Stagiaire de recherche - Université de Montréal

franco.delbalso@mila.quebec

Maîtrise recherche - Université de Montréal

Superviseur⋅e principal⋅e :

hasti.nafisi@mila.quebec

Jenna Karcheski

Stagiaire de recherche - Université de Montréal

Co-superviseur⋅e :

Laurence Perreault-Levasseur

jenna.karcheski@mila.quebec

Stagiaire de recherche - Université de Montréal

Superviseur⋅e principal⋅e :

Laurence Perreault-Levasseur

laura.leuzzi@mila.quebec

Doctorat - Université de Montréal

Co-superviseur⋅e :

Laurence Perreault-Levasseur

michael.barth@mila.quebec

Maîtrise recherche - Université de Montréal

Superviseur⋅e principal⋅e :

Laurence Perreault-Levasseur

missael-gabriel.barco@mila.quebec

Maîtrise recherche - Université de Montréal

Co-superviseur⋅e :

Laurence Perreault-Levasseur

nicolas.payot@mila.quebec

Postdoctorat - Université de Montréal

Superviseur⋅e principal⋅e :

Laurence Perreault-Levasseur

pablo.lemos@mila.quebec

Parker Levesque

Maîtrise recherche - Université de Montréal

Superviseur⋅e principal⋅e :

Laurence Perreault-Levasseur

parker.levesque@mila.quebec

Doctorat - Université de Montréal

Co-superviseur⋅e :

Laurence Perreault-Levasseur

ronan.legin@mila.quebec

Sacha Perry-Fagant

Doctorat - Université de Montréal

Superviseur⋅e principal⋅e :

Laurence Perreault-Levasseur

sacha.perry-fagant@mila.quebec

Stagiaire de recherche - Université de Montréal

Co-superviseur⋅e :

Laurence Perreault-Levasseur

yung-hsin.lee@mila.quebec

Publications

TEMPLATES: Characterization of a Merger in the Dusty Lensing SPT0418-47 System

Jared Cathey

Anthony H. Gonzalez

Sidney Lower

Kedar A. Phadke

Justin Spilker

Manuel Aravena

Matthew Bayliss

Jack E. Birkin

Simon Birrer

Scott Chapman

Håkon Dahle

Christopher C. Hayward

Ryley Hill

Taylor A. Hutchison

Keunho J. Kim

Guillaume Mahler

Daniel P. Marrone

Desika Narayanan

Alexander Navarre … (voir 7 de plus)

Cassie Reuter

Jane R Rigby

Keren Sharon

Manuel Solimano

Nikolaus Sulzenauer

Joaquin Vieira

David Vizgan

2024-05-13

The Astrophysical Journal (publié)

Interpretable Machine Learning for Finding Intermediate-mass Black Holes

Mario Pasquato

Piero Trevisan

Abbas Askar

Pablo Lemos

Gaia Carenini

Michela Mapelli

2024-04-09

The Astrophysical Journal (publié)

Searching for Strong Gravitational Lenses

Cameron Lemon

Frederic Courbin

Anupreeta More

Paul Schechter

Raoul Cañameras

Ludovic Delchambre

Calvin Leung

Yiping Shu

Chiara Spiniello

Jonas Klüter

Richard G. McMahon

2024-02-21

Space Science Reviews (publié)

PQMass: Probabilistic Assessment of the Quality of Generative Models using Probability Mass Estimation

Pablo Lemos

Sammy N. Sharief

Nikolay Malkin

Laurence Perreault-Levasseur

2024-02-06

ArXiv (prépublication)

On Diffusion Modeling for Anomaly Detection

Victor Livernoche

Vineet Jain

Siamak Ravanbakhsh

Known for their impressive performance in generative modeling, diffusion models are attractive candidates for density-based anomaly detectio… (voir plus)n. This paper investigates different variations of diffusion modeling for unsupervised and semi-supervised anomaly detection. In particular, we find that Denoising Diffusion Probability Models (DDPM) are performant on anomaly detection benchmarks yet computationally expensive. By simplifying DDPM in application to anomaly detection, we are naturally led to an alternative approach called Diffusion Time Estimation (DTE). DTE estimates the distribution over diffusion time for a given input and uses the mode or mean of this distribution as the anomaly score. We derive an analytical form for this density and leverage a deep neural network to improve inference efficiency. Through empirical evaluations on the ADBench benchmark, we demonstrate that all diffusion-based anomaly detection methods perform competitively for both semi-supervised and unsupervised settings. Notably, DTE achieves orders of magnitude faster inference time than DDPM, while outperforming it on this benchmark. These results establish diffusion-based anomaly detection as a scalable alternative to traditional methods and recent deep-learning techniques for standard unsupervised and semi-supervised anomaly detection settings.

2024-01-16

ICLR.cc/2024/Conference (spotlight)

Extended Lyman-alpha emission towards the SPT2349-56 protocluster at $z=4.3$

Yordanka Apostolovski

Manuel Aravena

Timo Anguita

Matthieu Béthermin

James R. Burgoyne

Scott Chapman

C. Breuck

Anthony R Gonzalez

Max Gronke

Lucia Guaita

Ryley Hill

Sreevani Jarugula

E. Johnston

M. Malkan

Desika Narayanan

Cassie Reuter

Manuel Solimano

Justin Spilker

Nikolaus Sulzenauer … (voir 5 de plus)

Joaquin Vieira

Joaquin Daniel Vieira

David Vizgan

Axel Wei

Axel Weiß

Deep spectroscopic surveys with the Atacama Large Millimeter/submillimeter Array (ALMA) have revealed that some of the brightest infrared so… (voir plus)urces in the sky correspond to concentrations of submillimeter galaxies (SMGs) at high redshift. Among these, the SPT2349-56 protocluster system is amongst the most extreme examples given its high source density and integrated star formation rate. We conducted a deep Lyman-alpha line emission survey around SPT2349-56 using the Multi-Unit Spectroscopic Explorer (MUSE) at the Very Large Telescope (VLT) in order to characterize this uniquely dense environment. Taking advantage of the deep three-dimensional nature of this survey, we performed a sensitive search for Lyman-alpha emitters (LAEs) toward the core and northern extension of the protocluster, which correspond to the brightest infrared regions in this field. Using a smoothed narrowband image extracted from the MUSE datacube around the protocluster redshift, we searched for possible extended structures. We identify only three LAEs at

2023-12-20

Astronomy & Astrophysics (publié)

Improving Gradient-guided Nested Sampling for Posterior Inference

Pablo Lemos

Will Handley

Nikolay Malkin

Laurence Perreault-Levasseur

We present a performant, general-purpose gradient-guided nested sampling algorithm, …

2023-12-06

ArXiv (preprint)

Active learning meets fractal decision boundaries: a cautionary tale from the Sitnikov three-body problem

Nicolas Payot

Mario Pasquato

Alessandro A. Trani

Laurence Perreault-Levasseur

Chaotic systems such as the gravitational N-body problem are ubiquitous in astronomy. Machine learning (ML) is increasingly deployed to pred… (voir plus)ict the evolution of such systems, e.g. with the goal of speeding up simulations. Strategies such as active Learning (AL) are a natural choice to optimize ML training. Here we showcase an AL failure when predicting the stability of the Sitnikov three-body problem, the simplest case of N-body problem displaying chaotic behavior. We link this failure to the fractal nature of our classification problem's decision boundary. This is a potential pitfall in optimizing large sets of N-body simulations via AL in the context of star cluster physics, galactic dynamics, or cosmology.

2023-11-29

ArXiv (prépublication)

Bayesian Imaging for Radio Interferometry with Score-Based Priors

No'e Dia

M. J. Yantovski-Barth

Alexandre Adam

Micah Bowles

Pablo Lemos

A. Scaife

Laurence Perreault-Levasseur

U. Montŕeal

Ciela Institute

Flatiron Institute

2023-11-29

ArXiv (prépublication)

Echoes in the Noise: Posterior Samples of Faint Galaxy Surface Brightness Profiles with Score-Based Likelihoods and Priors

Alexandre Adam

Connor Stone

Connor Bottrell

Ronan Legin

Laurence Perreault-Levasseur

Examining the detailed structure of galaxy populations provides valuable insights into their formation and evolution mechanisms. Significant… (voir plus) barriers to such analysis are the non-trivial noise properties of real astronomical images and the point spread function (PSF) which blurs structure. Here we present a framework which combines recent advances in score-based likelihood characterization and diffusion model priors to perform a Bayesian analysis of image deconvolution. The method, when applied to minimally processed \emph{Hubble Space Telescope} (\emph{HST}) data, recovers structures which have otherwise only become visible in next-generation \emph{James Webb Space Telescope} (\emph{JWST}) imaging.

2023-11-29

ArXiv (prépublication)

Learning an Effective Evolution Equation for Particle-Mesh Simulations Across Cosmologies

Nicolas Payot

Pablo Lemos

Laurence Perreault-Levasseur

Carolina Cuesta-lazaro

C. Modi

2023-11-29

ArXiv (prépublication)

The search for the lost attractor

Mario Pasquato

Syphax Haddad

Pierfrancesco Di Cintio

Alexandre Adam

Pablo Lemos

No'e Dia

Mircea Petrache

Ugo Niccolo Di Carlo

Alessandro A. Trani

Laurence Perreault-Levasseur

2023-11-27

ArXiv (prépublication)