16 papers · 1 filter
21-cm Brightness Temperature in a Unified-Dark-Sector Horndeski Theory
Bertha Cuadros-Melgar, Thanasis Karakasis, Eleftherios Papantonopoulos +1
We investigate the impact of scalar-tensor theories on the 21cm brightness temperature. We consider a specific model in Horndeski scalar-tensor theory in which dark matter and dark…
Binary Black Hole Coalescence and the Dynamics of Scalar Hair in Einstein-Maxwell-Scalar Theory
Jean Pierre DÃaz, P. A. González, Eleftherios Papantonopoulos +1
We investigate the head-on coalescence of charged binary black holes in Einstein-Maxwell-Scalar (EMS) theory using numerical relativity. The binaries are built from charged punctur…
Thermal Stability and QNMs of a Hairy Black Hole in the Presence of a Monopole Field
George Koutsoumbas, Andri Machattou, Eleftherios Papantonopoulos
We study the stability of a generalization of the GHS-GM black hole in the presence of a dilaton and a monopole field. We find that the thermal behaviour of system depends on the s…
Formation of Bound States in Quintessence Alternative Theories
George Koutsoumbas, Andri Machattou, Eleftherios Papantonopoulos
We study the formation and behaviour of bound states formed outside the horizon of a black hole in the presence of quintessence matter. Calculating the Regge and Wheeler potential…
Observational Tests of Regular Black Holes with Scalar Hair and their Stability
P. A. González, Marco Olivares, Eleftherios Papantonopoulos +1
We study the geodesic structure and observable properties of asymptotically flat regular black holes sourced by a phantom scalar field characterized by a scalar charge . This pa…
Time Like Geodesics of Regular Black Holes with Scalar Hair
P. A. González, Marco Olivares, Eleftherios Papantonopoulos +1
We investigate timelike geodesics in asymptotically flat regular black holes supported by a phantom scalar field characterized by a scalar charge . This parameter removes the ce…