MULTIMESSENGER ASTROPHYSICS
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- Versione italiana
- Academic year
- 2022/2023
- Teacher
- CRISTIANO GUIDORZI
- Credits
- 6
- Didactic period
- Secondo Semestre
- SSD
- FIS/05
Training objectives
- The epochal discovery of the first merger of a binary neutron star system in 2017 with both gravitational and electromagnetic waves heralded the birth of so-called multimessenger astronomy and opened yet unexplored channels to investigate the Universe. This course reviews some of the hottest topics in this newborn field. Special attention is paid to some of the most powerful astrophysical transients that play a crucial role in the evolution of the Universe, such as gamma-ray bursts, mergers of binary systems of compact objects as sources of gravitational waves, fast radio bursts, supernovae explosions, as well as their mutual connections. These phenomena are the subject of cutting-edge research. Particular emphasis is given to the classes of transients, that have recently been discovered in different windows of the electromagnetic spectrum and/or through the detection of gravitational waves and/or high-energy neutrinos. Not only are these sources per se interesting for the physics itself that is responsible for the observed highly energetic processes (strong gravity regime, implications on stellar evolution, jet formation, explosive stellar nucleosynthesis and origin of elements, relativistic shock physics, cosmic ray acceleration) but thanks to their luminosity they also represent unique probes of the Universe at different cosmological distances, out to the reionization epoch. These novel fields of research are bubbling with new findings and are the focus of worldwide scientific communities. The course also outlines the current and future dedicated experiments.
The student will be supplied with the formal rigour and will show their abilities in properly formulating and addressing problems concerning the treated subjects, required to undertake any research activity in the related fields. Prerequisites
- The course requires familiarity with the following topics: special and general relativity, classical electromagnetism, general physics, classical and quantum mechanics, stellar structure and evolution, statistical physics, radiative transport and radiative processes, dynamics of astrophysical fluids and shock waves, particle acceleration mechanisms.
Course programme
- Main topics: Supernovae classification and basic physics (12 hours). Gamma-ray bursts (12 hours). Gravitational waves from binary systems (12 hours). Fast-radio bursts (8 hours). Sources of high-energy neutrinos (2). Current and forthcoming experiments in the field of multimessenger astrophysics (8).
Detailed topics: stellar explosions. Supernovae: hydrodynamics of a SN. Observational and physical classification. Thermonuclear and core-collapse SNe. SN light curve interpretation and modelling: photospheric and nebular phases. Shock break-out. Superluminous SNe: observed properties and proposed mechanisms. Gamma-ray bursts: classification and interpretations. Compactness problem and evidence for ultra-relativistic outflow. GRB afterglows and jets. Long GRB progenitors: core-collapse of hydrogen-stripped massive stars. Short GRB progenitors: mergers of binary neutron star systems. Gravitational wave emission: binary neutron star systems and the Hulse-Taylor pulsar. Gravitational waves from coalescing binaries. Gravitational wave detection through interferometers and results from the first runs of the LIGO-Virgo experiments. The first merger of a binary neutron star system detected with both gravitational and electromagnetic waves: GW170817 and GRB170817A and the birth of multimessenger astronomy. Kilonova. The novel phenomenon of fast radio bursts, along with some possible interpretations. Cosmic high-energy neutrinos: discovery of TeV-PeV neutrinos from extragalactic sources at cosmological distances. Multimessenger observations of a flaring blazar coincident with a high-energy neutrino and implications. Review of current and future experiments in the multimessenger study of the transient sky: wide-field, high-cadence surveys in different windows of the electromagnetic spectrum (ZTF; VRO -former LSST-; SKA; CTA), current (LIGO-Virgo) and future generation (2G, 3G) gravitational wave interferometers, high-energy neutrino observatories (IceCube and next generation experiments). Didactic methods
- The lectures are delivered through slides that the teacher makes available on the web soon after they have been presented and discussed. During classes the teacher very often intersperses slides with calculations of the relevant quantities, which are estimated by means of specific examples and exercises. This way, the student becomes very familiar with the kind of exam and the sort of questions he/she will be expected to address in the oral exam, as well as with the evaluation criteria adopted by the teacher.
Learning assessment procedures
- During classes the teacher occasionally assigns exercises along with the numerical values of the solutions to motivate the students to practice and test the knowledge they are expected to acquire on the topics presented by the teacher. A detailed step-by-step solution is available on request to the students in the following weeks. The final exam consists of a unique oral session with a typical duration of 45 to 60 minutes, during which the student is asked both general questions about theory and more specific problems. These, in particular, will test the student's capability of properly addressing the problems. To this aim, the student will have to know the values of the fundamental constants and how to use them to estimate the requested astrophysical quantities.
The exam aims at assessing the expertise acquired by the student, their ability to establish connections between the different topics and aspects of the course, as well as the formal mathematical rigour demanded by each topic. Reference texts
- Slides are made available. The first four textbooks listed below are the main source of reference for the course. The remaining textbooks are additional sources for a more in-depth study.
1. H. Bradt, "Astrophysics Processes", Cambridge
2. D. Branch, J.C. Wheeler, "Supernova Explosions", Springer.
3. S. Weinberg, "Lectures on Astrophysics", Cambridge University Press.
4. D. Arnett, "Supernovae and Nucleosynthesis", Princeton.
5. J. José, "Stellar Explosions - Hydrodynamics and Nucleosynthesis", CRC Press.
6. K. Thorne, R. Blandford, "Modern Classical Physics", Princeton.
7. M. Longair, "High Energy Astrophysics", Cambridge University Press.
8. G.B. Rybicki, A.P. Lightman, "Radiative Processes in Astrophysics", Wiley
9. M. Vietri, "Astrofisica delle Alte Energie", Bollati Boringhieri.
10. Recent and forthcoming review papers published in peer-review journals.
