Bulletin of the American Physical Society
APS April Meeting 2010
Volume 55, Number 1
Saturday–Tuesday, February 13–16, 2010; Washington, DC
Session H14: Black Holes |
Hide Abstracts |
Sponsoring Units: GGR Chair: Clifford Will, Washington University in St. Louis Room: Washington 4 |
Sunday, February 14, 2010 10:45AM - 10:57AM |
H14.00001: Simulating the emission from shocked disks and black hole--neutron star mergers Matthew Anderson, Luis Lehner, David Neilsen, Miguel Megevand Astrophysical systems that radiate strongly in both electromagnetic and gravitational wave bands are of particular interest for study since the combined information can provide access to a number of rich phenomena. We simulate the possible electromagnetic emission from two scenarios: a disk perturbed by a recoiling super-massive black hole and the post-merger remnant disk from a black hole--neutron star merger. We present radiation transfer results from several configurations of these systems using different radiation models. [Preview Abstract] |
Sunday, February 14, 2010 10:57AM - 11:09AM |
H14.00002: A Numerical Study of Skyrmion Collisions Benjamin Gutierrez We present results on numerical experiments on the relativistic scattering of skyrmions and domain walls in $2+1$ and $3+1$ dimensions. Parallel adaptive mesh refinement is implemented to study the collisions of spherically symmetric (hedgehog) skyrmion configurations. We investigate reported numerical instabilities and the hyperbolic nature of the system in the relativistic limit. [Preview Abstract] |
Sunday, February 14, 2010 11:09AM - 11:21AM |
H14.00003: Over-spinning a black hole with a test body Ted Jacobson, Thomas Sotiriou A black hole of a given mass has a maximum possible spin. For greater spin, the corresponding solution to the Einstein equation has a naked singularity. Thus the question: can one spin up a black hole and expose a naked singularity? It has long been known that a {\it maximally} spinning black hole can not be over-spun by tossing in a test body. However, we find that if instead the black hole starts out with below maximal spin, then over-spinning can be achieved. We find that the requirements on the size and internal structure of the test body can be met if the body carries in either orbital or spin angular momentum. Our analysis neglects radiative and self-force effects, which may of course prevent the over-spinning. [Preview Abstract] |
Sunday, February 14, 2010 11:21AM - 11:33AM |
H14.00004: Gravitational and Electromagnetic Signatures from the Tidal Disruption of a White Dwarf by an Intermediate Mass Black Hole Roland Haas, Tanja Bode, Pablo Laguna Observations of the gravitational and electromagnetic radiation from the tidal disruption of a white dwarf by an intermediate mass black hole (IMBH) could provide evidence for the existence of IMBHs. During the inspiral and violent disruption of the star, the system will emit both gravitational waves and possibly X-ray radiation from the remnant accretion disk around the IMBH, which together will allow both the system's location and internal parameters to be measured. We present results for the first fully general relativistic hydrodynamics simulations of these encounters focusing not only on the gravitational wave emission not but also the electromagnetic signatures during the disruption and subsequent accretion. Our code uses the successful puncture recipe as implemented in an enhanced version our vacuum MayaKranc code coupled to the hydrodynamics code Whisky. [Preview Abstract] |
Sunday, February 14, 2010 11:33AM - 11:45AM |
H14.00005: Using Strong Field Images near Sgr A* to Probe Extra Dimensions Amitai Bin-Nun In recent years, theories of uncompactified extra dimensions have been the subject of much study. As of now, there are few observational tests of extra dimensions. Now, building on recent work in calculating the magnitudes of images in the strong-field of gravity, I use metrics for black holes in the Randall-Sundrum (RS) braneworld and apply them to the class of S-stars near Sgr A*. Using a modified lens equation to account for the strong field nature of the lensing and using data from surveys of the Galactic Center, I calculate differences in magnification between a black hole in a 3+1 model and in a RS-braneworld scenario. In ideal cases, this difference in magnification can be detected in next generational surveys and serve as an experimental verification of extra dimensions. [Preview Abstract] |
Sunday, February 14, 2010 11:45AM - 11:57AM |
H14.00006: Is the central object in the galaxy a black hole? Laleh Sadeghian, Clifford Will The spin and quadrupole moment of the supermassive black hole at the Galactic center can in principle be measured by studying the precessions of the orbital planes of stars in high-eccentricity orbits within milliparsec distance of the black hole [1]. Measuring these precessions could yield a test of the black hole no-hair theorem, and thus verify if the central object in the Galaxy is really a black hole. Other factors that might perturb these orbits include a population of other stars orbiting the black hole, a distribution of dark matter near the black hole and tidal distortions of the stars as they pass near the black hole at perihelion. We calculate the effects of these perturbing factors analytically by using standard orbital perturbation theory, and compare them with the relativistic precessions. \\[4pt] [1] C. M. Will, Astrophys. J. Lett. 674, L25 (2008) [Preview Abstract] |
Sunday, February 14, 2010 11:57AM - 12:09PM |
H14.00007: A simple non-singular black hole model Manasse Mbonye We present a new and simple model of a non-singular black hole
(NSBH) as an end result of gravitational collapse. The matter
density grows from ?$_{m}$=0, at the matter boundary surface R
inside the Schwarzschild horizon, to a maximum ?=?$_{max}$ at a
well defined position 0$ |
Sunday, February 14, 2010 12:09PM - 12:21PM |
H14.00008: Kerr-Schild Method and the Geodesic Structure in a Codimension-2 Brane Black Holes Nelson Zamorano, Susana Aguilar, Bertha Cuadros Melgar In this work we consider black hole solutions in a five-dimensional gravity. We include a Gauss-Bonnet term in the bulk and an induced gravity term on a 2-brane of codimension-2. Applying the Kerr-Schild method\footnote{A. H. Taub, Ann. of Phys. \textbf{220}, 326 (1981).} to a background known solution\footnote{B. Cuadros--Melgar, E. Papatonopoulos, M. Tsoukalas and V. Zamarias, \textit{Phys. Rev. Lett.} \textbf{100, }221601 (2008).} we have been able to generate additional solutions which include charge, angular momentum and a scalar field. In an effort to understand the geometric structure of these new spacetimes, we display a set of relevant geodesic families generated in these geometries. [Preview Abstract] |
Sunday, February 14, 2010 12:21PM - 12:33PM |
H14.00009: A Practical Foundation for Mapping Black Hole Spacetimes Sarah Vigeland, Scott Hughes Observations have shown that the universe contains many compact and massive objects that are believed to be black holes. Precise observations of orbital motion near candidate black holes have the potential to determine if they have the spacetime structure predicted by general relativity. We propose to compare strong-field observations of compact objects with the spacetime of bumpy black holes: objects whose multipolar structure is almost, but not quite, equal to that of the Kerr spacetime. We build bumpy black hole spacetimes by adding a perturbation onto a Kerr black hole, and we show how to map the perturbation onto changes in the multipole moments. The perturbation results in changes to the orbital frequencies which we calculate using Hamilton-Jacobi techniques. [Preview Abstract] |
Follow Us |
Engage
Become an APS Member |
My APS
Renew Membership |
Information for |
About APSThe American Physical Society (APS) is a non-profit membership organization working to advance the knowledge of physics. |
© 2024 American Physical Society
| All rights reserved | Terms of Use
| Contact Us
Headquarters
1 Physics Ellipse, College Park, MD 20740-3844
(301) 209-3200
Editorial Office
100 Motor Pkwy, Suite 110, Hauppauge, NY 11788
(631) 591-4000
Office of Public Affairs
529 14th St NW, Suite 1050, Washington, D.C. 20045-2001
(202) 662-8700