Particle acceleration and radio emission for SGRs/AXPs as white dwarf pulsars

37th Brazilian Meeting on Nuclear Physics

Lobato, R.V.^1 ; Coelho, Jaziel^2 ; Malheiro, M.^1

Departamento de Física, Instituto Tecnológico de Aeronáutica, Vila das Acácias, São José dos Campos, SP

12228-900, Brazil^1

Dipartimento di Fisica and ICRA, Sapienza Università di Roma, P.le Aldo Moro, 5, Rome

I-00185, Italy^2

关键词: Electron-positron pairs;    Magnetic field line;    Model-based OPC;    Pair production;    Particle acceleration;    Soft gamma repeaters;    Strong magnetic fields;    Surface magnetic field;   

Others  :  https://iopscience.iop.org/article/10.1088/1742-6596/630/1/012015/pdf
DOI  :  10.1088/1742-6596/630/1/012015

来源: IOP

【 摘 要 】

Recently, an alternative model based on white dwarfs pulsars has been proposed to explain a class of pulsars known as Soft Gamma Repeaters (SGR) and Anomalus X-Ray Pulsars (AXP) [6][4], usually named as magnetars. In this model the magnetized white dwarfs can have surface magnetic field B ∼ 107- 1010G and rotate very fast with frequencies ω ∼ 1 rad/s, allowing them to produce large electromagnetic (EM) potentials and generate electron-positron pairs. These EM potentials are comparable with the ones of neutron stars pulsars with strong magnetic fields. In our study we consider two possible processes associated with the particle acceleration: in one we have the pair production near to the star polar caps i.e., inside the light cylinder where magnetic-field lines are closed, on the other the creation of pair is in the Outer Magnetosphere i.e., far away of the star surface where magnetic field are open [1]. This analysis of the possibility of radio emission was done for all the 23 SGRs/AXPs of the McGill Online Magnetar Catalog [7] that contains the current information available on these sources. Our work is a first attempted to find an explanation for the puzzle why for all the SGRs/AXPs was expected radio emission, but it was observed in only four of them.