Possible Association of Two Stellar Bowshocks with Unidentified Fermi Sources

Authors
Sánchez Ayaso, Estrella; Del Valle, María V.; Martí, Josep; Romero, Gustavo Esteban; Luque Escamilla, Pedro L.
Publication Year
2018
Language
English
Format
article
Status
Published version
Description
The bowshocks of runaway stars had been theoretically proposed as gamma-ray sources. However, this hypothesis has not been confirmed by observations to date. In this paper, we present two runaway stars (λ Cep and LS 2355) whose bowshocks are coincident with the unidentified Fermi gamma-ray sources 3FLG J2210.1+5925 and 3FGL J1128.7-6232, respectively. After performing a cross-correlation between different catalogs at distinct wavelengths, we found that these bowshocks are the most peculiar objects in the Fermi position ellipses. Then we computed the inverse Compton emission and fitted the Fermi data in order to test the viability of both runaway stars as potential counterparts of the two high-energy sources. We obtained very reasonable values for the fitted parameters of both stars. We also evaluated the possibility for the source 3FGL J1128.7-6232, which is positionally coincident with a H ii region, to be the result of background cosmic-ray protons interacting with the matter of the cloud, as well as the probability of a pure chance association. We conclude that the gamma rays from these Fermi sources might be produced in the bowshocks of the considered runaway stars. In such a case, these would be the first sources of this class ever detected at gamma rays.
Fil: Sánchez Ayaso, Estrella. Universidad de Jaén; España
Fil: Del Valle, María V.. Universitat Potsdam; Alemania
Fil: Martí, Josep. Universidad de Jaén; España
Fil: Romero, Gustavo Esteban. Provincia de Buenos Aires. Gobernación. Comisión de Investigaciones Científicas. Instituto Argentino de Radioastronomía. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto Argentino de Radioastronomía; Argentina. Universidad Nacional de La Plata. Facultad de Ciencias Astronómicas y Geofísicas; Argentina
Fil: Luque Escamilla, Pedro L.. Universidad de Jaén; España
Subject
OUTFLOWS
STARS: WINDS
Astronomía
Ciencias Físicas
CIENCIAS NATURALES Y EXACTAS
Access level
Open access
License
https://creativecommons.org/licenses/by-nc-sa/2.5/ar/
Repository
CONICET Digital (CONICET)
Institution
Consejo Nacional de Investigaciones Científicas y Técnicas
OAI Identifier
oai:ri.conicet.gov.ar:11336/82420