Great Balls of Fire: Star Formation in Gas Clouds Accelerated by a Hot Wind

Fuente: arXiv
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Auteurs principaux: Tonnesen, Stephanie, Smith, Rory, Poggianti, Bianca, Vulcani, Benedetta, Akerman, Nina, Gullieuszik, Marco, Giunchi, Eric, Marasco, Antonino, Ignesti, Alessandro
Format: Preprint
Publié: 2026
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author Tonnesen, Stephanie
Smith, Rory
Poggianti, Bianca
Vulcani, Benedetta
Akerman, Nina
Gullieuszik, Marco
Giunchi, Eric
Marasco, Antonino
Ignesti, Alessandro
author_facet Tonnesen, Stephanie
Smith, Rory
Poggianti, Bianca
Vulcani, Benedetta
Akerman, Nina
Gullieuszik, Marco
Giunchi, Eric
Marasco, Antonino
Ignesti, Alessandro
contents Satellite galaxies undergo ram pressure stripping, in which their gas is directly removed by a hydrodynamical interaction with the surrounding host halo gas. In clusters, ram pressure stripped tails of gas have been observed to be multiphase, even forming stars within the stripped material. Some observations find a specific age gradient along the tail, with old stars closer to the galaxy disk, and a ``fireball'' toy model has been proposed in which a gas cloud being accelerated away from a galaxy continuously forms stars. In this paper, we simulate individual gas clouds (with masses of ~10$^6$ M$_\odot$ and radii of a few-100 pc) interacting with an intracluster medium wind, and include star formation. We find that our accelerating clouds do generally produce a stellar age gradient with younger stars formed farther along the wind direction and with higher velocities. However, our simulations are more physically accurate than an empirical model of monolithic cloud acceleration, leading to strongly nonmonotonic age gradients. First, the evolution of the gas cloud, both from cloud compression and collapse as well as from the shredding of cloud material into downwind filaments, can lead to stars formed simultaneously at a range of heights and velocities. Second, the gravity from the gas and stars of the cloud can lead to velocity evolution of newly-formed stars. We conclude that the most distinct fireball stellar age gradients are formed from star-forming clouds that are rapidly accelerated and shredded by their surroundings.
format Preprint
id arxiv_https___arxiv_org_abs_2603_26899
institution arXiv
publishDate 2026
record_format arxiv
spellingShingle Great Balls of Fire: Star Formation in Gas Clouds Accelerated by a Hot Wind
Tonnesen, Stephanie
Smith, Rory
Poggianti, Bianca
Vulcani, Benedetta
Akerman, Nina
Gullieuszik, Marco
Giunchi, Eric
Marasco, Antonino
Ignesti, Alessandro
Astrophysics of Galaxies
Satellite galaxies undergo ram pressure stripping, in which their gas is directly removed by a hydrodynamical interaction with the surrounding host halo gas. In clusters, ram pressure stripped tails of gas have been observed to be multiphase, even forming stars within the stripped material. Some observations find a specific age gradient along the tail, with old stars closer to the galaxy disk, and a ``fireball'' toy model has been proposed in which a gas cloud being accelerated away from a galaxy continuously forms stars. In this paper, we simulate individual gas clouds (with masses of ~10$^6$ M$_\odot$ and radii of a few-100 pc) interacting with an intracluster medium wind, and include star formation. We find that our accelerating clouds do generally produce a stellar age gradient with younger stars formed farther along the wind direction and with higher velocities. However, our simulations are more physically accurate than an empirical model of monolithic cloud acceleration, leading to strongly nonmonotonic age gradients. First, the evolution of the gas cloud, both from cloud compression and collapse as well as from the shredding of cloud material into downwind filaments, can lead to stars formed simultaneously at a range of heights and velocities. Second, the gravity from the gas and stars of the cloud can lead to velocity evolution of newly-formed stars. We conclude that the most distinct fireball stellar age gradients are formed from star-forming clouds that are rapidly accelerated and shredded by their surroundings.
title Great Balls of Fire: Star Formation in Gas Clouds Accelerated by a Hot Wind
topic Astrophysics of Galaxies
url https://arxiv.org/abs/2603.26899