view Abstract Citations (2) References (32) Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS A General Relativistic Hydrostatic Model for a Galaxy Hojman, Roberto ; Pena, Leda ; Zamorano, Nelson Abstract A general relativistic, hydrostatic, and asymptotically flat model for a galaxy is studied. It considers four spherically symmetric regions, properly matched and with a specific profile density assigned to each one of them. We assume that the galaxy is dominated by the dark mass everywhere except at the nucleus, where the visible matter prevails. In our model, the luminous matter located outside the nucleus of the galaxy behaves as test particles orbiting in a dark matter bath and its orbital velocity grows slowly with distance. The end of the galaxy is marked by the vanishing of the pressure. In our model, this condition generates a jump in the density at the outer region of the galaxy and, as a consequence, a change in the slope of the orbital velocity of test particles there. The specific shape of this bump depends on the model used. In our case, the inner structure of the galaxy is constructed following the observational data and the existence of this outer overdensity is proved on general grounds. This feature of the model seems to exist in a set of galaxies that displays a bump in the orbital velocity at the farthest end of their observed region. This effect, if it exists, may be difficult to single out from the background noise of the data. The sudden jump in the density introduced by this model is proposed here as a possible source for the γ-ray bursts detected by the Burst and Transient Source Experiment (BATSE). In this case, the overdensity would contain, eventually, a halo of neutron stars lying at the edge of our Galaxy. The model is scale-invariant and for this reason can be applied to other cases of physical interest. We have also compared our results with those obtained with the Newtonian isothermal sphere. Publication: The Astrophysical Journal Pub Date: July 1993 DOI: 10.1086/172856 Bibcode: 1993ApJ...411..541H Keywords: Astronomical Models; Dark Matter; Galactic Nuclei; Galactic Structure; Hydrostatics; Relativistic Theory; Asymptotic Methods; Galactic Mass; Gamma Ray Bursts; Mass To Light Ratios; Spiral Galaxies; Astrophysics; GALAXIES: KINEMATICS AND DYNAMICS; GALAXIES: NUCLEI; RELATIVITY full text sources ADS | data products SIMBAD (7)