Chapter 3
Magnetars: A Short Review and Some
Sparse Considerations
Paolo Esposito, Nanda Rea, and Gian Luca Israel
Abstract We currently know about 30 magnetars: seemingly isolated neutron
stars whose properties can be (in part) comprehended only acknowledging that
they are endowed with magnetic fields of complex morphology and exceptional
intensity—at least in some components of the field structure. Although magnetars
represent only a small percentage of the known isolated neutron stars, there are
almost certainly many more of them, since most magnetars were discovered in
transitory phases called outbursts, during which they are particularly noticeable.
In outburst, in fact, a magnetar can be brighter in X-rays by orders of magnitude
and usually emit powerful bursts of hard-X/soft-gamma-ray photons that can be
detected almost everywhere in the Galaxy with all-sky monitors such as those
on board the Fermi satellite or the Neil Gehrels Swift Observatory. Magnetars
command great attention because the large progress that has been made in their
understanding is proving fundamental to fathom the whole population of isolated
neutron stars, and because, due to their extreme properties, they are relevant for
a vast range of different astrophysical topics, from the study of gamma-ray bursts
and superluminous supernovae, to ultraluminous X-ray sources, fast radio bursts,
and even to sources of gravitational waves. Several excellent reviews with different
P. Esposito ()
Scuola Universitaria Superiore IUSS Pavia, Pavia, Italy
INAF - Istituto di Astrofisica Spaziale e Fisica Cosmica di Milano, Milano, Italy
e-mail: paolo.esposito@iusspavia.it
N. Rea
Institute of Space Sciences (ICE, CSIC), Barcelona, Spain
Institut d’Estudis Espacials de Catalunya (IEEC), Barcelona, Spain
Astronomical Institute “Anton Pannekoek”, University of Amsterdam, Amsterdam,
The Netherlands
e-mail: rea@ice.csic.es
G. L. Israel
Osservatorio Astronomico di Roma, INAF, Monteporzio Catone, Rome, Italy
e-mail: gianluca@oa-roma.inaf.it
© Springer-Verlag GmbH Germany, part of Springer Nature 2021
T. M. Belloni et al. (eds.), Timing Neutron Stars: Pulsations, Oscillations
and Explosions, Astrophysics and Space Science Library 461,
https://doi.org/10.1007/978-3-662-62110-3_3
97
Magnetars: A Short Review and Some
Sparse Considerations
Paolo Esposito, Nanda Rea, and Gian Luca Israel
Abstract We currently know about 30 magnetars: seemingly isolated neutron
stars whose properties can be (in part) comprehended only acknowledging that
they are endowed with magnetic fields of complex morphology and exceptional
intensity—at least in some components of the field structure. Although magnetars
represent only a small percentage of the known isolated neutron stars, there are
almost certainly many more of them, since most magnetars were discovered in
transitory phases called outbursts, during which they are particularly noticeable.
In outburst, in fact, a magnetar can be brighter in X-rays by orders of magnitude
and usually emit powerful bursts of hard-X/soft-gamma-ray photons that can be
detected almost everywhere in the Galaxy with all-sky monitors such as those
on board the Fermi satellite or the Neil Gehrels Swift Observatory. Magnetars
command great attention because the large progress that has been made in their
understanding is proving fundamental to fathom the whole population of isolated
neutron stars, and because, due to their extreme properties, they are relevant for
a vast range of different astrophysical topics, from the study of gamma-ray bursts
and superluminous supernovae, to ultraluminous X-ray sources, fast radio bursts,
and even to sources of gravitational waves. Several excellent reviews with different
P. Esposito ()
Scuola Universitaria Superiore IUSS Pavia, Pavia, Italy
INAF - Istituto di Astrofisica Spaziale e Fisica Cosmica di Milano, Milano, Italy
e-mail: paolo.esposito@iusspavia.it
N. Rea
Institute of Space Sciences (ICE, CSIC), Barcelona, Spain
Institut d’Estudis Espacials de Catalunya (IEEC), Barcelona, Spain
Astronomical Institute “Anton Pannekoek”, University of Amsterdam, Amsterdam,
The Netherlands
e-mail: rea@ice.csic.es
G. L. Israel
Osservatorio Astronomico di Roma, INAF, Monteporzio Catone, Rome, Italy
e-mail: gianluca@oa-roma.inaf.it
© Springer-Verlag GmbH Germany, part of Springer Nature 2021
T. M. Belloni et al. (eds.), Timing Neutron Stars: Pulsations, Oscillations
and Explosions, Astrophysics and Space Science Library 461,
https://doi.org/10.1007/978-3-662-62110-3_3
97