We examine the images and shadows of thin accretion disks around rotating hairy black holes characterized by two non-trivial, time-periodic scalar fields, whose target space possesses non-flat Gaussian curvature. These black holes represent a viable alternative to the Kerr solution, exhibiting a significantly richer geodesic structure that influences both the accretion disk images and their associated shadows. By investigating how variations in scalar hair - quantified by a normalized charge - and the underlying curvature affect the observable features of the system, we identify distinct regimes in the visual appearance of both the disks and their shadows. For high values of the normalized charge, approaching the boson star limit, the shadow regions display chaotic patterns with numerous small, disconnected components across all curvatures. At moderately high levels of scalar hair, the chaotic nature of the shadows persists, yet a dominant central dark region begins to emerge, whose size and shape are strongly dependent on the Gaussian curvature. The accretion disk images reflect this transition: in low curvature target space, the disk appears highly distorted and fragmented, while increasing curvature leads to more coherent, symmetric, and stable configurations. As the normalized charge decreases further, both the disk and shadow images gradually converge toward those typical of the Kerr black hole, with the influence of the curvature becoming progressively less significant.
Visual Signatures of Scalar Hair in the Images of Accretion Disks and Shadows of Rotating Hairy Black Holes
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Black Hole Workshops
Next workshop:
XVIII Black Holes Workshop, Lisbon, 2025
18-19 December 2025
Previous workshops in the series:
I Black Holes Workshop, Porto, 2008
II Black Holes Workshop, Lisbon, 2009
III Black Holes Workshop, Minho, 2010
IV Black Holes Workshop, Aveiro, 2011
V Black Holes Workshop, Lisbon, 2012
VI Black Holes Workshop, Minho 2013
VII Black Holes Workshop, Aveiro 2014
VIII Black Holes Workshop, Lisbon 2015
IX Black Holes Workshop, Minho 2016
X Black Holes Workshop, Aveiro 2017
XI Black Holes Workshop, Lisbon, 2018
XII Black Holes Workshop, Minho, 2019
XIII Black Holes Workshop, Lisbon, 2020
XIV Black Holes Workshop, Aveiro, 2021
XV Black Holes Workshop, Lisbon, 2022
XVI Black Holes Workshop, Porto, 2023
XVII Black Holes Workshop, Aveiro, 2024
Numerical data
NewFunFICO network
Our group coordinates the Marie Sklodowska Curie Staff Exchange NewFunFiCO network (Jan 2023- Dec 2026)
More info here
FunFiCO Network
Our group coordinates the Marie Curie RISE FunFiCO network (Dec 2017- Dec 2023)
More info here
EuCAPT Consortium
GWVerse COST
StronGrHEP Network
Our group was part of the RISE StronGrHEP network (2016-2019)
Meetings:
Paris, 12-13 May 2016
Azores, 3-8 July 2017
Osaka, 4-8 September 2017
NRHEP Network Meetings
Our group coordinated the "Numerical Relativity and High Energy Physics" IRSES network (2012-2015). Here is a list of the global network meetings organized:
First Meeting:
9-13 July 2012, Aveiro, Portugal
Second Meeting:
11-14 March 2013, Lisbon, Portugal
Third Meeting:
6-10 January 2014, Mississippi, USA
Fourth Meeting:
7-10 July 2015, Rome, Italy
Fifth Meeting:
28 Sep-2 Oct 2015, Belém, Brazil
Ph.D. and Post-doctoral opportunities
Contact us If you are interested in pursuing graduate studies/research in our group.
Information for prospective Ph.D. students can be found here.
Past Ph.D. theses from our group can be found here.
Working as a researcher in Portugal - a quick guide.