Showing papers by "Richard Dodson published in 2021"
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Curtin University1, San Diego State University2, Monash University, Clayton campus3, University of Birmingham4, Australian Research Council5, Chinese Academy of Sciences6, Texas Tech University7, Smithsonian Institution8, University of Amsterdam9, Korea University of Science and Technology10, Korea Astronomy and Space Science Institute11, University of Western Australia12, University of Tübingen13, Joint Institute for Nuclear Research14, Instituto Geográfico Nacional15, Commonwealth Scientific and Industrial Research Organisation16, University of Southampton17, University of Oxford18, New York University Abu Dhabi19, University of Alberta20, University of Erlangen-Nuremberg21
TL;DR: In this paper, the authors used radio astrometry to refine the distance to the black hole X-ray binary Cygnus X-1, which was found to be 2.22 − 0.17 + 0.18 kiloparsecs.
Abstract: The evolution of massive stars is influenced by the mass lost to stellar winds over their lifetimes. These winds limit the masses of the stellar remnants (such as black holes) that the stars ultimately produce. We use radio astrometry to refine the distance to the black hole X-ray binary Cygnus X-1, which we find to be 2.22 − 0.17 + 0.18 kiloparsecs. When combined with archival optical data, this implies a black hole mass of 21.2 ± 2.2 solar masses, higher than previous measurements. The formation of such a high-mass black hole in a high-metallicity system (within the Milky Way) constrains wind mass loss from massive stars.
106 citations
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TL;DR: In this article, the authors explore the population of small-amplitude, rapid rotational changes in the Vela pulsar and determine the rate of occurrence and sizes of its smallest glitches.
Abstract: Context. Glitches are sudden increases in the rotation rate ν of neutron stars, which are thought to be driven by the neutron superfluid inside the star. The Vela pulsar presents a comparatively high rate of glitches, with 21 events reported since observations began in 1968. These are amongst the largest known glitches (17 of them have sizes Δν /ν ≥ 10−6 ) and exhibit very similar characteristics. This similarity, combined with the regularity with which large glitches occur, has turned Vela into an archetype of this type of glitching behaviour. The properties of its smallest glitches, on the other hand, are not clearly established.Aims. We explore the population of small-amplitude, rapid rotational changes in the Vela pulsar and determine the rate of occurrence and sizes of its smallest glitches. This will help advance our understanding of the actual distribution of glitch sizes and inter-glitch waiting times in this pulsar, which has implications for theoretical models of the glitch mechanism.Methods. High-cadence observations of the Vela pulsar were taken between 1981 and 2005 at the Mount Pleasant Radio Observatory. An automated systematic search was carried out that investigated whether a significant change of spin frequency ν and/or the spin-down rate takes place at any given time.Results. We find two glitches that have not been reported before, with respective sizes Δν /ν of (5.55 ± 0.03) × 10−9 and (38 ± 4) × 10−9 . The latter is followed by an exponential-like recovery with a characteristic timescale of 31 d. In addition to these two glitch events, our study reveals numerous events of all possible signatures (i.e. combinations of Δν and signs), all of them small with |Δν |/ν , which contribute to the Vela timing noise.Conclusions. The Vela pulsar presents an under-abundance of small glitches compared to many other glitching pulsars, which appears genuine and not a result of observational biases. In addition to typical glitches, the smooth spin-down of the pulsar is also affected by an almost continuous activity that can be partially characterised by small step-like changes in ν , or both. Simulations indicate that a continuous wandering of the rotational phase, following a red spectrum, could mimic such step-like changes in the timing residuals.
13 citations
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Curtin University1, San Diego State University2, University of Birmingham3, Monash University4, Chinese Academy of Sciences5, Texas Tech University6, Smithsonian Institution7, University of Amsterdam8, Korea Astronomy and Space Science Institute9, University of Western Australia10, University of Tübingen11, Jive Software12, Commonwealth Scientific and Industrial Research Organisation13, University of Southampton14, University of Oxford15, New York University Abu Dhabi16, University of Alberta17, University of Erlangen-Nuremberg18
TL;DR: In this paper, the authors used radio astrometry to refine the distance to the black hole X-ray binary Cygnus X-1, which was found to be $2.22 − 0.18 − 0.17 − 1.2
Abstract: The evolution of massive stars is influenced by the mass lost to stellar winds over their lifetimes. These winds limit the masses of the stellar remnants (such as black holes) that the stars ultimately produce. We use radio astrometry to refine the distance to the black hole X-ray binary Cygnus X-1, which we find to be $2.22^{+0.18}_{-0.17}$ kiloparsecs. When combined with previous optical data, this implies a black hole mass of $21.2\pm2.2$ solar masses, higher than previous measurements. The formation of such a high-mass black hole in a high-metallicity system constrains wind mass loss from massive stars.
2 citations