skip to main content
OSTI.GOV title logo U.S. Department of Energy
Office of Scientific and Technical Information

Title: THE INFLUENCE OF GAS DYNAMICS ON MEASURING THE PROPERTIES OF THE BLACK HOLE IN THE CENTER OF THE MILKY WAY WITH STELLAR ORBITS AND PULSARS

Abstract

Observations of stars and pulsars orbiting the black hole in the center of the Milky Way offer the potential of measuring not only the mass of the black hole but also its spin and quadrupole moment, thereby providing observational verification of the no-hair theorem. The relativistic effects that will allow us to measure these higher moments of the gravitational field, however, are very small and may be masked by drag forces that stars and pulsars experience orbiting within the hot, tenuous plasma that surrounds the black hole. The properties of this plasma at large distances from the central object have been measured using observations of the extended X-ray emission that surrounds the point source. At distances comparable to the black hole event horizon, the properties of the accretion flow have been constrained using observations of its long-wavelength emission and polarization, as well as of the size of the emitting region at 1.3 mm. I use models of the plasma density and temperature at various distances from the black hole to investigate the effect of hydrodynamic drag forces on future measurements of the higher moments of its gravitational field. I find that hydrodynamic drag does not preclude measurements of the blackmore » hole spin and quadrupole moment using high-resolution observations of stars and pulsars that orbit within a few thousand gravitational radii from its horizon.« less

Authors:
 [1]
  1. Astronomy Department, University of Arizona, 933 N. Cherry Ave., Tucson, AZ 85721 (United States)
Publication Date:
OSTI Identifier:
22086365
Resource Type:
Journal Article
Journal Name:
Astrophysical Journal
Additional Journal Information:
Journal Volume: 759; Journal Issue: 2; Other Information: Country of input: International Atomic Energy Agency (IAEA); Journal ID: ISSN 0004-637X
Country of Publication:
United States
Language:
English
Subject:
79 ASTROPHYSICS, COSMOLOGY AND ASTRONOMY; ACCRETION DISKS; ASTRONOMY; ASTROPHYSICS; BLACK HOLES; DISTANCE; GRAVITATIONAL FIELDS; MASS; MILKY WAY; ORBITS; PHOTON EMISSION; PLASMA; PLASMA DENSITY; POLARIZATION; PULSARS; QUADRUPOLE MOMENTS; RELATIVISTIC RANGE; SPIN; STARS; X RADIATION

Citation Formats

Psaltis, Dimitrios. THE INFLUENCE OF GAS DYNAMICS ON MEASURING THE PROPERTIES OF THE BLACK HOLE IN THE CENTER OF THE MILKY WAY WITH STELLAR ORBITS AND PULSARS. United States: N. p., 2012. Web. doi:10.1088/0004-637X/759/2/130.
Psaltis, Dimitrios. THE INFLUENCE OF GAS DYNAMICS ON MEASURING THE PROPERTIES OF THE BLACK HOLE IN THE CENTER OF THE MILKY WAY WITH STELLAR ORBITS AND PULSARS. United States. doi:10.1088/0004-637X/759/2/130.
Psaltis, Dimitrios. Sat . "THE INFLUENCE OF GAS DYNAMICS ON MEASURING THE PROPERTIES OF THE BLACK HOLE IN THE CENTER OF THE MILKY WAY WITH STELLAR ORBITS AND PULSARS". United States. doi:10.1088/0004-637X/759/2/130.
@article{osti_22086365,
title = {THE INFLUENCE OF GAS DYNAMICS ON MEASURING THE PROPERTIES OF THE BLACK HOLE IN THE CENTER OF THE MILKY WAY WITH STELLAR ORBITS AND PULSARS},
author = {Psaltis, Dimitrios},
abstractNote = {Observations of stars and pulsars orbiting the black hole in the center of the Milky Way offer the potential of measuring not only the mass of the black hole but also its spin and quadrupole moment, thereby providing observational verification of the no-hair theorem. The relativistic effects that will allow us to measure these higher moments of the gravitational field, however, are very small and may be masked by drag forces that stars and pulsars experience orbiting within the hot, tenuous plasma that surrounds the black hole. The properties of this plasma at large distances from the central object have been measured using observations of the extended X-ray emission that surrounds the point source. At distances comparable to the black hole event horizon, the properties of the accretion flow have been constrained using observations of its long-wavelength emission and polarization, as well as of the size of the emitting region at 1.3 mm. I use models of the plasma density and temperature at various distances from the black hole to investigate the effect of hydrodynamic drag forces on future measurements of the higher moments of its gravitational field. I find that hydrodynamic drag does not preclude measurements of the black hole spin and quadrupole moment using high-resolution observations of stars and pulsars that orbit within a few thousand gravitational radii from its horizon.},
doi = {10.1088/0004-637X/759/2/130},
journal = {Astrophysical Journal},
issn = {0004-637X},
number = 2,
volume = 759,
place = {United States},
year = {2012},
month = {11}
}