Shadows of Sgr A$$^{*}$$ black hole surrounded by superfluid dark matter halo
Kimet Jusufi, Mubasher Jamil, Tao Zhu
Abstract
Abstract In this paper we construct a black hole solution surrounded by superfluid dark matter and baryonic matter, and study their effects on the shadow images of the Sgr A $$^{*}$$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:msup><mml:mrow/><mml:mrow><mml:mrow/><mml:mo>∗</mml:mo></mml:mrow></mml:msup></mml:math> black hole. To achieve this goal, we have considered two density profiles for the baryonic matter described by the spherical exponential profile and the power law profile including a special case describing a totally dominated dark matter galaxy. Using the present values for the parameters of the superfluid dark matter and baryonic density profiles for the Sgr A $$^{*}$$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:msup><mml:mrow/><mml:mrow><mml:mrow/><mml:mo>∗</mml:mo></mml:mrow></mml:msup></mml:math> black hole, we find that the effects of the superfluid dark matter and baryonic matter on the size of shadows are almost negligible compared to the Kerr vacuum black hole. In addition, we find that by increasing the baryonic mass the shadow size increases considerably. This result can be linked to the matter distribution in the galaxy, namely the baryonic matter is mostly located in the galactic center and, therefore, increasing the baryonic matter can affect the size of black hole shadow compared to the totally dominated dark matter galaxy where we observe an increase of the angular diameter of the Sgr A $$^{*}$$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:msup><mml:mrow/><mml:mrow><mml:mrow/><mml:mo>∗</mml:mo></mml:mrow></mml:msup></mml:math> black hole of the magnitude $$10^{-5}\,\upmu $$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mrow><mml:msup><mml:mn>10</mml:mn><mml:mrow><mml:mo>-</mml:mo><mml:mn>5</mml:mn></mml:mrow></mml:msup><mml:mspace/><mml:mi>μ</mml:mi></mml:mrow></mml:math> arcsec.