High-energy neutrinos from Population III Microquasars

CARULLI, AGUSTÍN MATÍAS; REYNOSO, MATÍAS M.

Ciudad Autónoma de Buenos Aires

Congreso; The 15th International Conference On The Dark Side Of The Universe; 2019

INSTITUTO DE FISICA DE BUENOS AIRES (IFIBA) ; (CONICET - UBA)

Microquasars (MQs) are binary systems composed by a star which feeds mass to a compact object through an accretion disk. The compact object, usually a black hole (BH), launches oppositely directed jets which are typically observed in our galaxy through their broadband electromagnetic emission. MQs could have also been formed by the first generations of stars in the universe, i.e., Population III (Pop III) stars. Such PopIII MQs could have been essential contributors to the intergalactic medium ionization procceses that took place during the period known as ?cosmic reionization?. Unlike gamma rays, which would have been absorbed in their cosmic travelling through the long distances involved, the neutrinos produced in these sources may plausibly leave their trail in present detectors such as the IceCube Neutrino Observatory.In the present work, we develop a model that accounts for the main particle processes occuring within Pop III MQs jets, with the purpose of obtaining a diffuse neutrino flux that may be observed from the Earth, and comparing the results with IceCube data.We define different zones within the Pop III MQ jets where particle interactions can occur, and we inject primary particles (i.e protons and electrons) in each of them. A transport equation is proposed for each zone, which contains the information of the particle energy loss due to radiative, acceleration, and escape processes. Once primary particles distributions are obtained in each zone, pions and muons distributions can be computed, as well as the neutrino output produced by their decays. Finally, adopting a rate of generation of Pop III MQs based on previous works, it is possible to obtain the diffuse neutrino flux by integration over the redshift z, the line-of-sight angle and the MQs lifetime.We find that for a set of parameters suitable for Pop III MQ jets, the most relevant sites for neutrino production in the jets are the jet base zone and the conical jet zone. The diffuse neutrino flux obtained by adding all the contributions are found to reach the level of a significant part of IceCube data.