# Course on Neutron Star Physics

Europe/Zurich
Sala de Xuntas bloque IV / Zoom (IGFAE)

### Sala de Xuntas bloque IV / Zoom

#### IGFAE

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Description

Neutron stars are probably the most exotic objects in the Universe: indeed, they present extreme and quite unique properties both in their macro- and micro-physics. Indeed, the physics of compact stars and of the stellar systems they form requires expertise from disciplines that are generally mostly disjointed, but now have to work sinergetically: high-energy astrophysics, gravitational physics, nuclear and hadronic physics, neutrino physics, QCD, superfluid hydrodynamics, plasma physics.

This course will offer a general and multi-disciplinar overview of the present understanding of the physics of neutron stars to master and PhD students, young scientists and established researchers.

This hybrid course will take place at IGFAE and online via Zoom. Online connection details will be distributed to the registered participants in due time.

Participants
• AKASH SINGH
• Alberto García Martín-Caro
• Alejandro Mata Ali
• Alexandre Brea Rodriguez
• Alicia Muñoz Ramos
• ALVAREZ POL HECTOR Not Supplied
• Ana Lorenzo Medina
• Andrzej Wereszczynski
• Andrés Bermúdez
• Antía Graña González
• Boris Betancourt
• Clara Landesa Gómez
• Damian Garcia-Castro
• David Castaño Bandín
• David García Allo
• Deepak Aryal
• Deepthi Godaba Venkata
• Diego Costas Rodríguez
• Eloi Pazos Rial
• Enrique Zas
• felix riehn
• Gabriel Garcia
• Helena Barreiro
• Imanol Corredoira
• Isabel Mª Vázquez Martínez
• Jaime Alvarez-Muniz
• Javier Mas Sole
• Jorge Castelo Mourelle
• Jose Luis Rodriguez Sanchez
• José Fernando Mandeur Díaz
• Juan Ammerman-Yebra
• Juan Lois Fuentes
• Lola Cortina
• Lorenzo Cazon
• Lukas Komisel
• Maria Jose Gomez Calero
• Martina Feijoo Fontán
• Martí Berenguer Mimó
• Marwan Yassir Ajoor
• Miguel Fernandez Gomez
• Miguel Huidobro
• Miguel Lozano González
• Miguel Ángel Escobedo Espinosa
• Praveen Kumar
• Ricardo Julio Rodríguez Fernández
• Roberto Guerrero Romero
• Sara Maggio
• Sergio Cabana Freire
• silvia gasparotto
• VAZQUEZ LOPEZ RICARDO ANTONIO Not Supplied
• Verónica Villa Ortega
• Xoán Mayo López
• Yago Lema Capeáns
• Ángel Morcillo Gómez
• Monday, November 15
• 1
Welcome
• Introduction to Neutron Stars
• 2
Introduction to neutron stars

n this lecture, I will cover the basics of neutron stars and pulsar as astrophysical objects and physics laboratories. Content of the lecture will brush off the following elements 1) a brief history of neutron stars and pulsars, 2) simple neutron star model (i.e. basic equation of state and structure), 3) simple pulsar model and observations (lighthouse model, P-Pdot/B-field/Edot, radio timing/searching), 4) physics laboratories (distance mapping, gravity/relativity tests, binary evolution).

Speaker: Rene Breton (The University of Manchester)
• Tuesday, November 16
• Observational characterization via EM emission
• 3
Basic observational aspects of pulsar classes

I will introduce pulsar classes and their relationships, focusing on how they are seen depending on what they do, and what they are.

Speaker: Dr Diego Torres (ICE-Barcelona)
• 4
High Energy emission of pulsars and their nebulae

I will focus on the high-energy emission of pulsars, trying to cover as well the basics on pulsar wind nebulae phenomenology, and in providing context for discussing the expectations coming with future observatories.

Speaker: Diego Torres ( IEEC / CSIC-ICE Barcelona)
• Dense nuclear matter
• 5
Baryon-baryon interactions and theoretical approaches to the nuclear EoS

In this part we will make an extensive reexamination of the baryon-baryon interaction discussing the different approaches that have been and are used in its construction. Then we will concentrate on several of the theoretical methods currently used to construct the nuclear EoS. We will illustrate both ab-inutio and phenomenological methods at zero and finite temperature and we will comfront them with the currently available data from both laboratory terrestial experiments and recent astrophysical observations.

Speaker: Dr Isaac Vidaña (INFN Sezione di Catania )
• Wednesday, November 17
• Dense nuclear matter
• 6
EoS and Neutron Star Structure

In this part we will analyze the importance of the nuclear EoS on the properties of neutron stars. We will discuss the main open challenges in the description of the EoS, mainly focussing on the limits of the current many-body techniques, the so-called "hyperon puzzle" and the dependence of cooling properties on the nuclar EoS.

Speaker: Isaac Vidaña (INFN Sezione di Catania )
• Nucleosynthesis during birth and death of neutron stars
• 7
Evolution of massive stars and core-collapse supernova.

The mass of a star defines the maximum temperature that can be reached in the stellar core and hence the possible burning products. Massive stars are able to follow all burning processes and produce an Iron core that finally collapses and leading to a core-collapse supernova explosion. The low mass limit defines what are the lowest mass neutron
stars that can be formed. Similarly there should be an upper mass limit such as the collapse leads to the formation of a black hole. Ascentaining those limits and its dependence on nuclear reactions is important to understand the population of stellar mass black holes and neutron stars that is accessible to gravitational wave interferometers.

Speaker: Prof. Gabriel Martínez-Pinedo (Technische Universitat Darmstadt - GSI)
• Dense nuclear matter
• 8
Perturbative QCD at high densities.

The lectures will detail the high-density cold quark-matter equation
of state (EoS) as described by perturbative Quantum Chromodynamics (pQCD), and
how this can constrain the Neutron Star EoS at lower densities. Topics covered
will include: (i) framework of relativistic thermal and high-density
perturbation theory, (ii) infrared problems in thermal field theory and their
resolution for the EoS, (iii) the general structure of the pQCD EoS and (iv)
current status of theoretical calculations.

Speaker: Dr Tyler Gorda (Technische Universitat Darmstadt)
• Thursday, November 18
• Present and future of neutron star physics using gravitational waves
• 9
Physics from binary neutron star mergers

On August 17, 2017, the LIGO and Virgo collaborations measured gravitational waves from the inspiral of two neutron stars in a galaxy 40 Mpc away. This spectacular event GW170817 was subsequently observed across the electromagnetic spectrum. This first multi-messenger binary neutron star observation provided new insights into the nuclear equation of state of matter, the nucleosynthesis of heavy elements, our understanding of gamma-ray bursts and jet physics, the speed of gravity, and cosmology, among many other things. But this event was also just the tip of the iceberg in terms of what we hope to learn with future gravitational-wave and electromagnetic observations. I will review what we learned from GW170817, and what we hope to learn in the future with the current- and next-generation of gravitational-wave instruments.

• Nucleosynthesis during birth and death of neutron stars
• 10
Nucleosynthesis in neutron star mergers.

Neutron star mergers constitute an important target for gravitational wave interferometers. Differently to black hole mergers they are expected to produce electromagnetic radiation. Such emission provides complementary information about the dynamics of the system to gravitational waves. An important source of electromagnetic emission is the radioactive decay of freshly synthesized heavy nuclei, the so
called kilonova electromagnetic transient. This emission was detected for the first time in the gravitational wave event GW170817 confirming that the r-process nucleosynthesis takes places in the ejecta of neutron star mergers. It provides an unique opportunity to learn about the "in situ" operation of the r-process.

Speaker: Gabriel Martínez Pinedo (GSI Darmstadt)
• Present and future of neutron star physics using gravitational waves
• 11
Multi-Messenger Studies of Binary Neutron Star Systems

We discuss how one can use numerical-relativity simulations to derive gravitational-wave and electromagnetic models describing the binary neutron star coalescence. Such models can be used to perform multi-messenger studies in which the gravitational wave signals GW170817, GW190425, and the observed electromagnetic signals AT2017gfo and GRB170817A are analyzed. We combine the obtained information with an analysis of X-ray and radio observations of single neutron stars, nuclear theory computations, and information from heavy-ion collisions. In general, nuclear physics - multi-messenger astronomy studies provide new constraints on the neutron-star equation of state and the Hubble constant.

Speaker: Tim Dietrich (Nikhef)
• Friday, November 19
• Present and future of neutron star physics using gravitational waves
• 12
The search for continuous gravitational waves in LIGO and Virgo detectors: methods, recent results and perspectives

Continuous gravitational waves (CWs) are emitted by sources with a mass quadrupole moment varying in time in a periodic or nearly-periodic manner. The emission of CWs is expected from spinning neutron stars, if asymmetric with respect to the rotation axis, or by more exotic sources, like those involving ultra-light bosons, which could be a component of dark matter. CWs have not been detected so far, due to their weakness with respect to the well-known coalescing compact binaries, and are subject of intense research worldwide. Given their persistent nature, the detection of CWs would revolutionise gravitational wave astronomy, providing a true laboratory’’ for astrophysics and fundamental physics. In this lecture, I will discuss some expected astrophysical sources of CWs, I will present the main data analysis techniques used for their search, the most relevant results obtained so far in the analysis of LIGO and Virgo data, and their astrophysical interpretation. I will conclude with future perspectives in this field.

Speaker: Dr Cristiano Palomba
• Neutron stars in the lab
• 13
Neutron stars in the lab

Because of their extreme density, neutron stars are made of unique states of matter that are difficult, or even impossible, to create on Earth. Extremely neutron-rich nuclei, nuclear superfluids, strange matter, deconfined quarks and colour condensate are some examples. Despite this difficulty, an important number of accelerator-based experiments try to reproduce some of these exotic matter states, or to provide micro-physics inputs required in neutron star modelization. Moreover, accreting neutron stars and neutron star mergers are responsible for the nucleosynthesis of heavy chemical elements in the Universe. In this talk I will review some of the experiments investigating the properties of neutron-rich nuclei, the equation of state of asymmetric nuclear matter, the role of short-range correlations in the formation of superfluid nucleon-nucleon pairs or the characterization of baryon-hyperon interaction.

Speaker: Jose Benlliure (University of Santiago de Compostela)