A model for the non-thermal emission of the very massive colliding-wind binary HD 93129A

Context. Recently, the colliding-wind region of the binary stellar system HD 93129A was resolved for the first time using Very Large Baseline Interferometry. This system, one of the most massive known binaries in our Galaxy, presents non-thermal emission in the radio band, which can be used to infer...

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Autores principales: Palacio, Santiago del, Bosch Ramon, Valentí, Romero, Gustavo Esteban, Benaglia, Paula
Formato: Articulo
Lenguaje:Inglés
Publicado: 2016
Materias:
Acceso en línea:http://sedici.unlp.edu.ar/handle/10915/85730
Aporte de:
id I19-R120-10915-85730
record_format dspace
institution Universidad Nacional de La Plata
institution_str I-19
repository_str R-120
collection SEDICI (UNLP)
language Inglés
topic Ciencias Astronómicas
Acceleration of particles
outflows
Radiation mechanisms: non-thermal
Stars: massive
Stars: winds
spellingShingle Ciencias Astronómicas
Acceleration of particles
outflows
Radiation mechanisms: non-thermal
Stars: massive
Stars: winds
Palacio, Santiago del
Bosch Ramon, Valentí
Romero, Gustavo Esteban
Benaglia, Paula
A model for the non-thermal emission of the very massive colliding-wind binary HD 93129A
topic_facet Ciencias Astronómicas
Acceleration of particles
outflows
Radiation mechanisms: non-thermal
Stars: massive
Stars: winds
description Context. Recently, the colliding-wind region of the binary stellar system HD 93129A was resolved for the first time using Very Large Baseline Interferometry. This system, one of the most massive known binaries in our Galaxy, presents non-thermal emission in the radio band, which can be used to infer the physical conditions in the system, and make predictions for the high-energy band. Aims. We intend to constrain some of the unknown parameters of HD 93129A through modeling the non-thermal emitter. We also aim to analyse the detectability of this source in hard X-rays and γ-rays. Finally, we want to predict how the non-thermal emission will evolve in the future, when the stars approach periastron. Methods. A broadband radiative model for the wind-collision region (WCR) has been developed taking into account the evolution of the accelerated particles streaming along the shocked region, the emission by different radiative processes, and the attenuation of the emission propagating through the local matter and radiation fields. We reproduce the available radio data, and make predictions of the emission in hard X-rays and γ-rays under different assumptions. Results. From the analysis of the radio emission, we find that the binary HD 93129A is more likely to have a low inclination and a high eccentricity, with the more massive star being currently closer to the observer. The minimum energy of the non-thermal electrons seems to be between ∼20-100 MeV, depending on the intensity of the magnetic field in the WCR. The latter can be in the range ∼20-1500 mG. Conclusions. Our model is able to reproduce the observed radio emission, and predicts that the non-thermal radiation from HD 93129A will increase in the near future. With instruments such as <i>NuSTAR</i>, <i>Fermi</i>, and CTA, it will be possible to constrain the relativistic particle content of the source, and other parameters such as the magnetic field strength in the WCR which, in turn, can be used to obtain upper-limits of the magnetic field on the surface of the very massive stars, thereby inferring whether magnetic field amplification is taking place in the particle acceleration region.
format Articulo
Articulo
author Palacio, Santiago del
Bosch Ramon, Valentí
Romero, Gustavo Esteban
Benaglia, Paula
author_facet Palacio, Santiago del
Bosch Ramon, Valentí
Romero, Gustavo Esteban
Benaglia, Paula
author_sort Palacio, Santiago del
title A model for the non-thermal emission of the very massive colliding-wind binary HD 93129A
title_short A model for the non-thermal emission of the very massive colliding-wind binary HD 93129A
title_full A model for the non-thermal emission of the very massive colliding-wind binary HD 93129A
title_fullStr A model for the non-thermal emission of the very massive colliding-wind binary HD 93129A
title_full_unstemmed A model for the non-thermal emission of the very massive colliding-wind binary HD 93129A
title_sort model for the non-thermal emission of the very massive colliding-wind binary hd 93129a
publishDate 2016
url http://sedici.unlp.edu.ar/handle/10915/85730
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