Photon Rings and Shadow Size for General Integrable Spacetimes
| dc.contributor.author | Salehi, Kiana | |
| dc.date.accessioned | 2023-08-08T14:17:11Z | |
| dc.date.available | 2023-08-08T14:17:11Z | |
| dc.date.issued | 2023-08-08 | |
| dc.date.submitted | 2023-07-27 | |
| dc.description.abstract | According to the no-hair theorem, the unique characteristics of astrophysical black holes are their masses and spins. However, recent observations from the Event Horizon Telescope (EHT) images of M87 and Sgr A* have allowed us to place constraints on possible deviations from this theory. To interpret these observations and compare them to other near horizon scale observations, we introduce a model-agnostic framework that explores deviations while maintaining generality. We start by considering a general spherically symmetric metric, which effectively applies for a polar observer in the slow rotation limit and then follow by relaxing these constraints to axi-symmetric and stationary spacetimes. We propose a nonperturbative, nonparametric spacetime-domain characterization of shadow size and related measurements that makes explicit the nature and power (or lack thereof) of shadow-size-based constraints, and facilitates comparisons among observations and targets. Furthermore, we demonstrate that relying solely on shadow size measurements does not impose a direct limitations on the value of the gtt component of the metric. However, in the case of spherically symmetric spacetime, it can impose a constraint on the radial derivative of gtt, while a more intricate constraint arises for the axi-symmetric spacetime. Moreover, the measurement of shadows and potential future observations of multiple photon rings do not provide any valuable information concerning the ergo-region and frame-dragging in axi-symmetric spacetime. | en |
| dc.identifier.uri | http://hdl.handle.net/10012/19656 | |
| dc.language.iso | en | en |
| dc.pending | false | |
| dc.publisher | University of Waterloo | en |
| dc.subject | Gravity | en |
| dc.title | Photon Rings and Shadow Size for General Integrable Spacetimes | en |
| dc.type | Master Thesis | en |
| uws-etd.degree | Master of Science | en |
| uws-etd.degree.department | Physics and Astronomy | en |
| uws-etd.degree.discipline | Physics | en |
| uws-etd.degree.grantor | University of Waterloo | en |
| uws-etd.embargo.terms | 0 | en |
| uws.contributor.advisor | Broderick, Avery | |
| uws.contributor.affiliation1 | Faculty of Science | en |
| uws.peerReviewStatus | Unreviewed | en |
| uws.published.city | Waterloo | en |
| uws.published.country | Canada | en |
| uws.published.province | Ontario | en |
| uws.scholarLevel | Graduate | en |
| uws.typeOfResource | Text | en |