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- Nestor Ortiz

My research focuses on the strong field regime of classical gravity within the framework of Einstein's theory of General Relativity, as well as certain alternative theories of gravity. Part of my interests involves fundamental aspects of the theoretical framework, whereas other part incorporates applications to astrophysics, which usually require a combination of analytical and numerical techniques. A particular problem that I have extensively explored is the validity of the Cosmic Censorship Conjecture for the gravitational collapse of a spherical dust star, first identifying and characterizing the conditions on the initial data leading to the formation of globally naked singularities, and then studying the stability of the associated Cauchy horizon under several classes of perturbations. I am also interested on the observational features of such naked singularities, which could potentially probe the Cosmic Censorship Conjecture.

Other ongoing projects involve: imprints of tidal deformation of slowly rotating neutron stars in gravitational wave signals; quasinormal modes of highly compact neutron stars in scalar-tensor gravity; emission of gamma-rays from coalescing binary neutron stars as electromagnetic counterparts of gravitational waves.

- National Researcher Level I. Mexican National Agency for Science and Technology.

- "Extended I-Love relations for slowly rotating neutron stars", Jeremie Gagnon-Bischoff, Stephen R. Green, Philippe Landry, and Nestor Ortiz. Physical Review D 97, 064042 (2018).
- "Cauchy horizon stability in a collapsing spherical dust cloud. II: Energy bounds for test fields and odd-parity gravitational perturbations", Nestor Ortiz and Olivier Sarbach. Classical and Quantum Gravity 35, 025010 (2017).
- "Fixing extensions to general relativity in the nonlinear regime", Juan Cayuso, Nestor Ortiz, and Luis Lehner. Physical Review D 96, 084043 (2017).
- "Global Crustal Dynamics of Magnetars in Relation to their Bright X-ray Outbursts", Christopher Thompson, Huan Yang, and Nestor Ortiz. The Astrophysical Journal, 841 1 (2017).
- "Highly compact neutron stars in scalar-tensor theories of gravity: spontaneous scalarization versus gravitational collapse", Raissa Mendes and Nestor Ortiz. Physical Review D 93, 124035 (2016).
- "Observational distinction between black holes and naked singularities: the role of the redshift function", Nestor Ortiz, Olivier Sarbach, and Thomas Zannias. Classical and Quantum Gravity 32, 247001 (2015).
- "Shadow of a naked singularity", Nestor Ortiz, Olivier Sarbach, and Thomas Zannias. Physical Review D 92, 044035 (2015).
- "Gravitational redshift of photons traversing a collapsing dust cloud and observable consequences", Nestor Ortiz and Olivier Sarbach. Physical Review D 90, 124058 (2014).
- "New class of quasinormal modes of neutron stars in scalar-tensor gravity", Raissa Mendes and Nestor Ortiz. arXiv: 1802.07847 (2018).
- "On the behaviour of non-radial null geodesics in self-similar Tolman-Bondi collapse", Nestor Ortiz, Olivier Sarbach, and Thomas Zannias. arXiv: 1503.08344 (2015).

- "The role of neutron stars in the era of gravitational wave astronomy", Gravity and Field Theory Seminar, Institute for Nuclear Sciences, Autonomous University of Mexico. (2018)
- "Tidal forces in neutron stars", Gravity Seminar, University of Michoacan, Morelia, Mexico. (2017)
- "On the stability of naked singularities arising from collapsing spherical dust stars", Seminar at Fluminense Federal University. Niteroi, Brasil. (2017)
- "Spontaneous scalarization of neutron stars in the unconstrained parameter regime of scalar- tensor theories", Annual NewCompStar Conference. Polish Academy of Sciences. Warsaw, Poland. (2017)
- "Gamma-ray emission from the coalescence of binary neutron stars: an electromagnetic counterpart of gravitational radiation", Invited talk at School on General Relativity and Gravitational Waves. Guadalajara, Mexico. (2016)
- "Spontaneous scalarization of neutron stars in the unconstrained parameter regime of scalar- tensor theories", Colloquium at Guanajuato State University. Leon, Mexico. (2016)
- "Spontaneous scalarization of neutron stars in the unconstrained parameter regime of scalar- tensor theories", 21st International Conference on General Relativity and Gravitation. New York, US. (2016)
- "On the observational distinction between black holes and naked singularities", PI-CITA Day. Canadian Institute for Theoretical Astrophysics, Toronto, Canada. (2015)
- "The shadow of a naked singularity", Midwest Relativity Meeting. Northwestern University, Evanston, US. (2015)
- "Light curves from binary neutron star coalescence", American Physical Society APR15 Meeting. Baltimore, US. (2015)
- "The shadow of a naked singularity", Cosmology Group Meeting.
- "On the stability of naked singularities arising from spherical dust collapse", Cosmology Group Meeting.

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