High-energy processes in starburst-driven winds

Müller, Ana L.; Romero, Gustavo E.; Roth, M.

doi:10.1093/mnras/staa1720

Cited by 26 publications

(19 citation statements)

References 52 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The next generation of telescopes with better angular resolution and sensitivity will allow unravelling the morphology of the diffuse non-thermal emitting region in SFGs, possibly resolving the emission coming from the disc from that originated in the halo or wind (see e.g. Romero et al 2018;Müller et al 2020;Peretti et al 2021). The panchromatic view of the SFRluminosity correlations in SFGs is a key to assess the physical processes that govern the non-thermal emission of these sources.…”

Section: Discussionmentioning

confidence: 99%

Exploring the physics behind the non-thermal emission from star-forming galaxies detected in gamma rays

Kornecki,

Peretti,

del Palacio

et al. 2021

Preprint

View full text Add to dashboard Cite

Context. Star-forming galaxies emit non-thermal radiation from radio to γ-rays. Observations show that their radio and γ-ray luminosities scale with their star formation rates, supporting the hypothesis that non-thermal radiation is emitted by cosmic rays produced by their stellar populations. However, the nature of the main cosmic-ray transport processes that shape the emission in these galaxies is still poorly understood, especially at low star formation rates. Aims. We aim to investigate the main mechanisms of global cosmic-ray transport and cooling in star-forming galaxies. The way they contribute in shaping the relations between non-thermal luminosities and star formation rates could shed light onto their nature, and allow to quantify their relative importance at different star formation rates. Methods. We develop a model to compute the cosmic-ray populations of star-forming galaxies, taking into account their production, transport and cooling. The model is parameterised only through global galaxy properties, and describes the non-thermal emission in both radio (at 1.4 GHz and 150 MHz) and γ-rays (in the 0.1-100 GeV band). We focus on the role of diffusive and advective transport by galactic winds, either driven by turbulent or thermal instabilities. We compare model predictions to observations, for which we compile a homogeneous set of luminosities in these radio bands, and update those available in γ rays. Results. Our model reproduces reasonably well the observed relations between the γ-ray or 1.4 GHz radio luminosities and the star formation rate, assuming a single power-law scaling of the magnetic field with the latter with index β = 0.3, and winds blowing either at Alfvenic speeds (∼ tens of km s −1 , for 5 M yr −1 ) or typical starburst wind velocities (∼ hundreds of km s −1 , for 5 M yr −1 ). Escape of cosmic rays is negligible for 30 M yr −1 . A constant ionisation fraction of the interstellar medium fails to reproduce the 150 MHz radio luminosity throughout the whole star formation rate range. Conclusions. Our results reinforce the idea that galaxies with high star formation rate are cosmic-ray calorimeters, and that the main mechanism driving proton escape is diffusion, whereas electron escape also proceeds via wind advection. They also suggest that these winds should be cosmic-ray or thermally-driven at low and intermediate star formation rates, respectively. Our results globally support that magnetohydrodynamic turbulence is responsible for the dependence of the magnetic field strength on the star formation rate and that the ionisation fraction is strongly disfavoured to be constant throughout the whole range of star formation rate.

show abstract

Section: Discussionmentioning

confidence: 99%

Exploring the physics behind the non-thermal emission from star-forming galaxies detected in gamma rays

Kornecki,

Peretti,

del Palacio

et al. 2021

Preprint

View full text Add to dashboard Cite

show abstract

“…If the length scale of the medium is higher than the thermal cooling length, the shock is adiabatic, otherwise it is radiative. A detailed discussion of the nature of shocks and their ability to accelerate particles is given in Müller et al (2020). The thermal cooling length of the wind is given by (McCray and Snow 1979):…”

Section: Particle Accelerationmentioning

confidence: 99%

Equatorial outflows driven by jets in Population III microquasars

Checa

Romero

Bosch‐Ramon

2021

Astrophys Space Sci

View full text Add to dashboard Cite

Binary systems of Population III can evolve to microquasars when one of the stars collapses into a black hole. When the compact object accretes matter at a rate greater than the Eddington rate, powerful jets and winds driven by strong radiation pressure should form. We investigate the structure of the jet-wind system for a model of Population III microquasar on scales beyond the jet-wind formation region. Using relativistic hydrodynamic simulations we find that the ratio of kinetic power between the jet and the disk wind determines the configuration of the system. When the power is dominated by the wind, the jet fills a narrow channel, collimated by the dense outflow. When the jet dominates the power of the system, part of its energy is diverted turning the wind into a quasi-equatorial flow, while the jet widens. From the results of our simulations, we implement semi-analytical calculations of the impact of the quasi-equatorial wind on scales of the order of the size of the binary system. Our results indicate that Population III microquasars might inject gamma rays and relativistic particles into the early intergalactic medium, contributing to its reionization at large distances from the binary system.

show abstract

“…The net result of such a strong energy release in a compact region is the growth of local temperature and pressure resulting eventually in a large-scale outflow expanding through the galactic halo. The power of the wind can range over several orders of magnitude, from 10 39 erg s −1 up to 10 45 erg s −1 , making this system unique for particle acceleration and multimessenger emission [4][5][6][7][8][9][10].…”

Section: Introductionmentioning

confidence: 99%