Screened modified gravity is inherently elusive: screening mechanisms suppress the propagation of additional gravitational degrees of freedom in typical astrophysical scenarios, allowing these theories to avoid constraints coming from weak field observations.
Following the first observation of gravitational waves from merging black holes in 2015, we have now observed gravitational wave signals from over 50 binary mergers. In this talk, I will review the most recent observations from the first half of the third LIGO and Virgo observing run. I will highlight some of the most novel events and will discuss the impacts of th
Ultralight bosonic fields are compelling dark-matter candidates and arise in a variety of beyond-Standard-Model scenarios. These fields can tap energy and angular momentum from spinning black holes through superradiant instabilities, during which a macroscopic bosonic condensate develops around the black hole.
Can a black hole be different from the Kerr paradigm depending on its spin? In paper to publishd in Physical Review Letters, Gr@v members C. Herdeiro and E. Radu, in collaboration with H. Silva and N. Yunes (U. Illinois at Urbana-Champaigne, US) and T. Sotirou (U. Nottingham, UK), show that the phenomenon of spontaneous scalarisation can lead to non-Kerr black holes, only if they spin fast enough.
João Oliveira successfully defended his Ph.D. thesis on Friday 20th November 2020. The committee, presided by Prof. A. Botelho and composed by Profs. D. Astefanesi, M. Zilhão, M. Piedade Ramos, E. Radu and C. Herdeiro (advisor) unanimously approved the thesis entitled "Aspects of Einstein-Maxwell-scalar models: Solitons, Duality and Scalarisation". Congratulations João!
Abstract: The bright blazar OJ 287 is the best-known candidate for hosting a supermassive black hole binary (SMBHB) in the present observable universe.
The 2020 FCT call for Scientific Research & Technological Development projects had 5847 applications, of which 3317 were considered eligible and 312 recommended for funding. In the Physical Sciences panel there were 139 applications; Gr@v's project, led by C.Herdeiro, a synergy between the different expertise of the group (strong gravity, astrophysics and high energy physics) was ranked first.
Pedro Cunha was one of the 7 selected researchers for a junior grant, nationwide, within 76 applicants in the Physical Sciences panel, in the third individual call for scientific employment stimulus, promoted by FCT. Pedro (re)joined our group as a post-doc in October 2020, after being a post-doctoral researcher at the Max Planck institute for gravitational physics in Golm, Germany. Congratulations Pedro!
Four new research students have joined Gr@v this fall: Jenzhi Yang, Ivo Sengo, Vasileios Vatellis and João Pino. Welcome!