We have identified 21 millisecond pulsars (MSPs) in globular cluster Terzan 5 by using the Green Bank Telescope, bringing the total of known MSPs in Terzan 5 to 24. These discoveries confirm fundamental predictions of globular cluster and binary system evolution. Thirteen of the new MSPs are in binaries, of which two show eclipses and two have highly eccentric orbits. The relativistic periastron advance for the two eccentric systems indicates that at least one of these pulsars has a mass 1.68 times greater than the mass of the Sun at 95% confidence. Such large neutron star masses constrain the equation of state of matter at or beyond the nuclear equilibrium density.
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http://dx.doi.org/10.1126/science.1108632 | DOI Listing |
Nature
January 2025
Perimeter Institute for Theoretical Physics, Waterloo, Ontario, Canada.
Science
January 2024
Osservatorio Astronomico di Cagliari, Istituto Nazionale di Astrofisica, I-09047 Selargius, Italy.
Some compact objects observed in gravitational wave events have masses in the gap between known neutron stars (NSs) and black holes (BHs). The nature of these mass gap objects is unknown, as is the formation of their host binary systems. We report pulsar timing observations made with the Karoo Array Telescope (MeerKAT) of PSR J0514-4002E, an eccentric binary millisecond pulsar in the globular cluster NGC 1851.
View Article and Find Full Text PDFPhys Rev Lett
October 2023
National Astronomical Observatories, Chinese Academy of Sciences, Beijing 100101, People's Republic of China.
Phys Rev Lett
August 2023
Department of Physics and Astronomy, University of Utah, Salt Lake City, Utah 84112, USA.
Over 10 years ago, Fermi observed an excess of GeV gamma rays from the Galactic Center whose origin is still under debate. One explanation for this excess involves annihilating dark matter, another requires an unresolved population of millisecond pulsars concentrated at the Galactic Center. In this work, we use the results from LIGO and Virgo's most recent all-sky search for quasimonochromatic, persistent gravitational-wave signals from isolated neutron stars, which is estimated to be about 20%-50% of the population, to determine whether unresolved millisecond pulsars could actually explain this excess.
View Article and Find Full Text PDFSensors (Basel)
August 2023
Department of Information Technologies and Communications, University of National and World Economy, 1700 Sofia, Bulgaria.
It is known that X-ray and gamma-ray pulsars can only be observed by spacecraft because signals from these pulsars are impossible to be detected on the Earth's surface due to their strong absorption by the Earth's atmosphere. The article is devoted to the theoretical aspects regarding the development of an autonomous radio navigation system for transport with a small receiving antenna, using radio signals from pulsars, similar to navigation systems for space navigation. Like GNSS systems (X-ray and radio), they use signals from four suitable pulsars to position the object.
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