Multifrequency Behaviour of High Energy Cosmic Sources in the GW Era

Abstract

We will discuss the importance of the "Multifrequency Astrophysics" as a pillar of an interdisciplinary approach for the knowledge of the physics of our Universe. Indeed, as largely demonstrated in the last decades, only with the multifrequency observations of cosmic sources it is possible to get near the whole behaviour of a source and then to approach the physics governing the phenomena that originate such a behaviour. In spite of this, a multidisciplinary approach in the study of each kind of phenomenon occurring in each kind of cosmic source is even more powerful than a simple "astrophysical approach". A clear example of a multidisciplinary approach is that of "The Bridge between the Big Bang and Biology". This bridge can be described by using the competences of astrophysicists, planetary physicists, atmospheric physicists, geophysicists, volcanologists, biophysicists, biochemists, and astrobiophysicists. The unification of such competences can provide the intellectual framework that will better enable an understanding of the physics governing the formation and structure of cosmic objects, apparently uncorrelated with one another, that on the contrary constitute the steps necessary for the life (e.g. Giovannelli, 2001). Indeed, a lot of the future research in astrophysics will be focussed on the discovery of exoplanets and on the possibility to detect signals for alien life somewhere in the Galaxy. An extension to a multidisciplinary approach is coming from the use of historical news reported in "old chronicle" that are a fundamental source for the newborn "archaeoastronomy". There are many problems in performing Simultaneous Multifrequency, Multisite, Multiinstrument, Multiplatform Measurements due to: (i) objective technological difficulties; (ii) sharing common scientific objectives; (iii) problems of scheduling and budgets; (iv) politic management of science. All these kind of measurements converge in what is now called Multimessenger Astrophysics, after the detection of gravitational wave events (GWEs) and the search for the electromagnetic counterparts of such events. A part of this paper is a summary of an updated version of the book "The Impact of the Space Experiments on Our Knowledge of the Physics of the Universe" published in 2004 by the Kluwer Academic Publishers, reprinted from the review paper by Giovannelli, F. & Sabau-Graziati, L.: 2004, Space Sci. Rev. 112, 1-443 (GSG2004), and subsequent considered lucubrations. In this paper we will provide several example that marked the continuous evolution on the knowledge of the physics of our Universe.

A Journey to Understand Our Universe

“…Among these, the system A 0535+26/HDE 245770 -HDE 245770 was nicknamed Flavia' star by Giovannelli & Sabau-Graziati (1992) -is the best known thanks to concomitant favorable causes, which rendered possible forty six years of coordinated multifrequency observations, most of them discussed in the past by e.g. Giovannelli & Sabau-Graziati (1992), Burger et al (1996), Piccioni et al (1999), and by Giovannelli & Sabau-Graziati (2011) and Giovannelli et al (2015a,b). Accretion powered X-ray pulsars usually capture material from the optical companion via stellar wind, since this primary star generally does not fill its Roche lobe.…”

“…After the first historical Frascati 1984 Workshop about "Multifrequency Behaviour of Galactic Accreting Sources" (Giovannelli, 1985), it is important to remind the long biennial series of the Frascati Workshops about "Multifrequency Behaviour of High Energy Cosmic Sources" started in 1995, whose refereed proceedings can be found in Giovannelli & Sabau-Graziati (1996).…”

The Golden Age of Cataclysmic Variables and Related Objects (some critical comments)

“…In my opinion, another open question is that about the nature of SS Cyg: NMCV or MCV (IP). There are many papers that discuss such a problem, like those by Giovannelli ( , 1996 (1999, 2012a,b). In particular in the latter two papers (2012a,b) a deep discussion of the pro and contra about the IP nature of SS Cyg is reported.…”

“…Briefly, SGRs and AXPs are a class of compact objects that show interesting observational properties (e.g. Mereghetti, 2008;Giovannelli & Sabau-Graziati, 2019), namely: rotational periods, P, in the range 5.5 − 11.8 s -contrary to the larger spread of those of HMXBs (0.069-few ×10 3 s -and spin-down ratesṖ in the range (0.05 -10) ×10 −11 s s −1 , larger than those of 'ordinary pulsars' (Ṗ ∼ 10 −15 s s −1 ); strong outbursts of energies in the range ∼ 10 41 -10 43 erg, and…”

“…The Golden Age of CVs Franco Giovannelli the system. Several proofs have been shown and discussed many times by Giovannelli's group in order to demonstrate the Intermediate Polar nature of it (e.g., Giovannelli, 1996, and references therein; Giovannelli & Sabau-Graziati, 1998; 2012a); indeed, SS Cygni shows characteristics of a NMCV, as well as those of IP and sometimes even those of polars, although its position in the log P spin -log P orb plane is very close to the line where IPs lie. Important results are coming from the SPITZER space telescope with the detection of an excess (3)(4)(5)(6)(7)(8) µm emission from MCVs, due to dust (Howell et al, 2006;Brinkworth et al, 2007).…”