From X-ray Binaries to Gamma-ray bursts: the time-domain richness of transient phenomena
Abstract
Transient phenomena show diverse high-energy behaviour at different time scales. In the `faster' regime — from seconds to hours — high-energy monitoring has facilitated the follow up of electromagnetic counterparts to gravitational waves and (short) gamma-ray bursts (GRBs), whereas in the `slower' regime — from days to months — these kind of studies have yielded to the extension of our understanding of the X-ray binary phenomenology. None of this progress could have been made without the key role of the Swift, INTEGRAL, MAXI, XMM-Newton and Chandra observatories. In the `slow' time-domain scenario, I will present the results of our X-ray monitoring campaigns focused on studying the low-luminosity state of Be/X-ray transients, which harbour highly magnetized (B∼10 12-10 13 G) neutron stars (NSs). We have observed that, at such luminosities, these systems show different transient behaviour, which is potentially linked to the neutron-star spin period. I will discuss our results in the context of the physical processes that could explain most of the observed phenomena. However, limiting our studies to high energies constrains our knowledge to the compact object and its surroundings, and ignores any feedback from the companion and its environment. Therefore, comprehensive multi-wavelength studies of these systems will broaden our understanding of the physical processes behind the observed emission and will help clarify the origin of the observed outflows. In the `fast' time-domain scenario, I will present the results of our latest systematic and comprehensive X-ray study of short GRB afterglows at late times. I will introduce the most updated jet opening angle distribution of short GRBs, which is determined utilising all the available broad-band (from X-rays to radio) afterglow information. This result has direct implications on the true energy scales of short GRBs and progenitor (NS-NS merger) rates.
- Publication:
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44th COSPAR Scientific Assembly. Held 16-24 July
- Pub Date:
- July 2022
- Bibcode:
- 2022cosp...44.1906R