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Cited by 472

The DOI matches its Crossref record; 67 of the 67 references it cites were found in a registry or an index.

Testing the rotational nature of the supermassive object M87* from the circularity and size of its first image

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Bambi, Cosimo, Freese, Katherine, Vagnozzi, Sunny, Visinelli, Luca·2019·Physical Review D
DOI 10.1103/physrevd.100.044057
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Abstract

The Event Horizon Telescope (EHT) collaboration has recently released the first image of a black hole (BH), opening a new window onto tests of general relativity in the strong field regime. In this paper, we derive constraints on the nature of M87* (the supermassive object at the center of the galaxy M87), exploiting the fact that its shadow appears to be highly circular, and using measurements of its angular size. We first consider the simple case where M87* is assumed to be a Kerr BH. We find that the inferred circularity of M87* excludes Kerr BHs with observation angle ${\ensuremath{\theta}}_{\mathrm{obs}}\ensuremath{\gtrsim}45\ifmmode^\circ\else\textdegree\fi{}$ for dimensionless rotational parameter $0.95\ensuremath{\lesssim}{a}_{*}\ensuremath{\le}1$ whereas the observation angle is unbounded for ${a}_{*}\ensuremath{\lesssim}0.9$. We then consider the possibility that M87* might be a superspinar, i.e., an object described by the Kerr solution and spinning so fast that it violates the Kerr bound by having $|{a}_{*}|>1$. We find that, within certain regions of parameter space, the inferred circularity and size of the shadow of M87* do not exclude the possibility that this object might be a superspinar.

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Metadata

Authors
Bambi, C., Freese, K., Vagnozzi, S., & Visinelli, L.
Venue
Physical Review D
Publisher
American Physical Society (APS)
Published
2019-08-29
Volume
100
Issue
4
ISSN
  • 2470-0010 (ISSN-L)
  • 2470-0029
DOI
10.1103/physrevd.100.044057
OpenAlex
W2971100406
Cited by
472
References
67
FWCI
26.53
Type
journal article
Language
en
Open access
bronze

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CoChat. (2026). Citation check: Testing the rotational nature of the supermassive object M87* from the circularity and size of its first image. https://app.cochat.ai/papers/10.1103/physrevd.100.044057
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Bambi, C., Freese, K., Vagnozzi, S., & Visinelli, L. (2019). Testing the rotational nature of the supermassive object M87* from the circularity and size of its first image. Physical Review D. https://doi.org/10.1103/physrevd.100.044057

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