Jul 5 – 10, 2021
Europe/Rome timezone

Shadows of hairy Kerr black holes and constraints from M87*

Jul 6, 2021, 6:55 AM
Talk in the parallel session Theoretical and observational studies of astrophysical black holes Theoretical and Observational Studies of Astrophysical Black Holes


Sushant Ghosh (Jamia millia Islamia)


We take on an extensive study of the rotating hairy Kerr black holes, which encompasses, in particular cases, the Kerr black hole ($\alpha=0$). We investigate ergosphere and shadows of the black holes to infer that their size and shape are affected due to the $l_0$ and are found to harbour a richer chaotic structure. In particular, the hairy Kerr black holes possess smaller size but more distorted shadows when compared with Kerr black holes. We also estimate the parameters $l_0$ and $a$ associated with hairy Kerr black holes using the shadow observables. The inferred circularity deviation $\Delta C \leq 0.1$ for the M87* black hole is satisfied, whereas shadow angular diameter $\theta_{d}=42 \pm 3 \mu as$, within $1 \sigma$ region, for a given choice of $\alpha$, places bounds on the parameters $a$ and $l_0$. Interestingly, the shadow axial ratio obeying $1< D_x \lesssim 4/3$ is in agreement with the EHT results and thus eventuates in the hairy Kerr black holes being suitable candidates for astrophysical black holes.

Primary authors

Sushant Ghosh (Jamia millia Islamia) Ms Misba Afrin (Centre for Theoretical Physics, Jamia Millia Islamia)

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