Astrophysics

Astrophysics is an area concerning various physical ranging from planetary sized systems, to galactic scale systems and beyond, that intersects various disciplines such as Newtonian dynamics, relativistic physics and particle physics processes.

For our latest developments/activities in this area, please see the listing below at the end of this article.

Exoplanets

An exoplanet is a planet outside the Solar System. In the Milky Way galaxy, it is expected that there are many billions of planets (at least one planet, on average, orbiting around each star, resulting in 100–400 billion exoplanets), with many more free-floating planetary-mass bodies orbiting the galaxy directly.

We study the long-term dynamics of known multi-planet systems. This allow us to test the accuracy of the orbital parameters' determinations, as well as to understand how these systems evolved. We also look for the stable zones in the gaps between already-known planets in order to determine where is it possible to locate Earth-like planets.

See here a movie made by the PhD Animation on "Exoplanets Explained", for a review on the main observational methods used to detect exoplanets.


Latest Astrophysics Publications

Einstein-Maxwell-dilaton neutral black holes in strong magnetic fields: topological charge, shadows and lensing, Haroldo C. D. Lima Junior, Jian-Zhi Yang, Luís C. B. Crispino, Pedro V. P. Cunha and Carlos A. R. Herdeiro; Phys. Rev. D 105 (2022) 064070, arXiv:2112.10802 [gr-qc].

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Regular Articles
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Spinning gauged boson and Dirac stars: a comparative study, Carlos Herdeiro, Ilya Perapechka, Eugen Radu, Yakov Shnir, Phys. Lett. B 824 (2022) 136811, arXiv:2111.14475 [gr-qc].

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Regular Articles
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All-sky, all-frequency directional search for persistent gravitational-waves from Advanced LIGO's and Advanced Virgo's first three observing runs, LIGO Scientific, VIRGO and KAGRA Collaborations, R. Abbott et al. (includes N. Sanchis-Gual); arXiv:2110.09834 [gr-qc].

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Regular Articles
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Search for continuous gravitational waves from 20 accreting millisecond X-ray pulsars in O3 LIGO data; LIGO Scientific, VIRGO and KAGRA Collaborations, R. Abbott et al. (includes N. Sanchis-Gual); arXiv:2109.09255 [astro-ph.HE].

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Regular Articles
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Virial identities in relativistic gravity: 1D effective actions and the role of boundary terms, Carlos A. R. Herdeiro, João M. S. Oliveira, Alexandre M. Pombo, Eugen Radu; Phys. Rev. D 104 (2021) 104051, arXiv:2109.05027 [gr-qc].

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Regular Articles
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Latest Astrophysics News & Events

A waveform catalogue for Proca star collisions

The detection of gravitational waves has been one of the most exciting scientific developments of the XXIst century. These detections are theory-driven, they rely on the existence of waveform libraries, which have been constructed for binary black holes and neutron stars. Gr@v members have collaborated on the construction of the first waveform catalogue for exotic compact objects, an effort led by former Gr@v member Nicolas Sanchis Gual (now at the U. Valencia).

The fate of the light-ring instability

In the paper "The fate of the light-ring instability" Gr@v members P. Cunha, C. Herdeiro and E. Radu, together with former member, currently at the U. Valencia, N. Sanchis-Gual, have unveiled the mystery of the fate of a large class of horizonless ultracompact objects, that could be potential black hole foils.

 

 

A long standing intriguing possibility is if the astrophysical black hole candidates could be some other kind of mysterious objects but without event horizons, the defining property of black holes.