J/MNRAS/494/228 The UTMOST pulsar timing programme - II (Lower+, 2020)
The UTMOST pulsar timing programme - II.
Timing noise across the pulsar population.
Lower M.E., Bailes M., Shannon R.M., Johnston S., Flynn C., Oslowski S.,
Gupta V., Farah W., Bateman T., Green A.J., Hunstead R., Jameson A.,
Jankowski F., Parthasarathy A., Price D.C., Sutherland A., Temby D.,
Venkatraman Krishnan V.
<Mon. Not. R. Astron. Soc., 494, 228-245 (2020)>
=2020MNRAS.494..228L 2020MNRAS.494..228L (SIMBAD/NED BibCode)
ADC_Keywords: Pulsars ; Stars, neutron ; Positional data ; Ephemerides ;
Radio sources
Keywords: methods: data analysis - astrometry - ephemerides - stars: neutron -
pulsars: general
Abstract:
While pulsars possess exceptional rotational stability, large-scale
timing studies have revealed at least two distinct types of
irregularities in their rotation: red timing noise and glitches. Using
modern Bayesian techniques, we investigated the timing noise
properties of 300 bright southern-sky radio pulsars that have been
observed over 1.0-4.8yr by the upgraded Molonglo Observatory Synthesis
Telescope (MOST). We reanalysed the spin and spin-down changes
associated with nine previously reported pulsar glitches, report the
discovery of three new glitches and four unusual glitch-like events in
the rotational evolution of PSR J1825-0935. We develop a refined
Bayesian framework for determining how red noise strength scales with
pulsar spin frequency (ν) and spin-down frequency (dν/dt), which
we apply to a sample of 280 non-recycled pulsars. With this new method
and a simple power-law scaling relation, we show that red noise
strength scales across the non-recycled pulsar population as
νa|dν/dt|b, where a=-0.84+0.47-0.49 and
b=0.97+0.16-0.19. This method can be easily adapted to utilize
more complex, astrophysically motivated red noise models. Lastly, we
highlight our timing of the double neutron star PSR J0737-3039, and
the rediscovery of a bright radio pulsar originally found during the
first Molonglo pulsar surveys with an incorrectly catalogued position.
Description:
The UTMOST project began with the backend upgrade to the refurbished
MOST (Bailes et al. 2017PASA...34...45B 2017PASA...34...45B). MOST is a Mills-Cross design
aperture synthesis telescope situated approximately 35km south-east of
Canberra, Australia. It is comprised of two 778m long east-west arms
that can be slewed in the north-south direction, and a static
north-south arm, that is being re-engineered as part of the UTMOST-2D
project (Day et al. in preparation). The telescope operates at a
central frequency of 835MHz covering a bandwidth of 31.25MHz. The
ring-shaped design of the antenna elements means the instrument is
mainly sensitive to right-hand circularly polarized emission.
We have performed an initial study of the rotational properties of 300
bright, southern-sky radio pulsars observed by UTMOST using the
Bayesian pulsar timing software TempoNest to characterize the
stochastic properties of our pulsar sample and to obtain unbiased
measurements of ν and dν/dt.
We list the measured astrometric and rotational parameters for each
pulsar in our sample in Table A1. The full list of the maximum
likelihood posterior values and associated 95 per cent confidence
intervals on the red noise parameters are presented in Appendix B.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
tablea1.dat 184 300 Astrometric and rotational parameters of all
pulsars analysed in this work
tableb1.dat 58 300 List of the preferred timing noise model, Bayes
factor and associated red noise parameters for
each pulsar in our data set
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See also:
J/MNRAS/484/3691 : UTMOST pulsar timing programme. I. (Jankowski+, 2019)
Byte-by-byte Description of file: tablea1.dat
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Bytes Format Units Label Explanations
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1- 11 A11 --- Name Pulsar name (JHHMM+DDMMA)
13- 14 I2 h RAh Right ascension (ICRS) at Ep=2015.7 (1)
16- 17 I2 min RAm Right ascension (ICRS) at Ep=2015.7 (1)
19- 26 F8.5 s RAs Right ascension (ICRS) at Ep=2015.7 (1)
28- 34 F7.5 s e_RAs Error on RAs (1σ)
36 A1 --- DE- Declination sign (ICRS) at Ep=2015.7 (1)
37- 38 I2 deg DEd Declination (ICRS) at Ep=2015.7 (1)
40- 41 I2 arcmin DEm Declination (ICRS) at Ep=2015.7 (1)
43- 49 F7.4 arcsec DEs Declination (ICRS) at Ep=2015.7 (1)
51- 56 F6.4 arcsec e_DEs Error on DEs (1σ)
58- 73 F16.12 Hz nu Pulsar spin frequency
75- 88 F14.12 Hz E_nu Upper error on nu (2)
90- 103 F14.12 Hz e_nu Lower error on nu (2)
105- 117 F13.6 10-15/s2 dnu/dt Pulsar spin-down frequency
119- 127 F9.6 10-15/s2 E_dnu/dt Upper error on dnu/dt (2)
129- 137 F9.6 10-15/s2 e_dnu/dt Lower error on dnu/dt (2)
139- 146 F8.4 10-24/s3 d2nu/dt2 ? Pulsar second spin-frequency derivative
148- 156 F9.3 10-24/s3 E_d2nu/dt2 ? Upper error on d2nu/dt2
158- 165 F8.3 10-24/s3 e_d2nu/dt2 ? Lower error on d2nu/dt2
167- 170 I4 --- NTOA Number of time of arrivals (TOAs)
172- 177 F6.2 yr T Observation time span
179- 184 A6 --- Flag Flag on the pulsar (3)
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Note (1): The positions are given in epoch MJD 57600
Note (2): Uncertainties on nu and dnu/dt represent the 95 per cent confidence
intervals scaled to the last digit
Note (3): Note as follows:
PPTA = Pulsar is observed as part of the Parkes Pulsar Timing Array project
(Manchester et al. 2013PASA...30...17M 2013PASA...30...17M)
B = Pulsar is a binary
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Byte-by-byte Description of file: tableb1.dat
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Bytes Format Units Label Explanations
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1- 11 A11 --- Name Pulsar name (JHHMM+DDMMA)
13- 14 A2 --- f_Name Flag on Name (1)
16- 22 A7 --- Model Preferred timing noise model (2)
24- 29 F6.1 [-] lnB ? Natural logarithm of the Bayes factor (3)
31- 35 F5.1 [-] logA ? Logarithm of the amplitude of the red noise
power law (in yr3/2) (4)
37- 39 F3.1 [-] E_logA ? Upper error on logA (in yr3/2) (5)
41- 43 F3.1 [-] e_logA ? Lower error on logA (in yr3/2) (5)
45- 48 F4.1 --- beta ? Spectral index of the red noise power law (4)
50- 53 F4.1 --- E_beta ? Upper error on beta (5)
55- 58 F4.1 --- e_beta ? Lower error on beta (5)
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Note (1): Flag as follows:
a = Millisecond pulsar
b = Clock reference pulsar
Note (2): Model as follows:
WTN = White timing noise model
PLRN = Power-law red noise model
PLRN+F2 = Power-law red noise with frequency turnover model
Note (3): The listed Bayes factor is taken as being the difference in evidences
between the best model and the next simplest model
Note (4): See section 3.1 of the article for more details
Note (5): Errors indicate the 95 per cent confidence intervals
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History:
From electronic version of the journal
References:
Jankowski et al., Paper I 2019MNRAS.484.3691J 2019MNRAS.484.3691J, Cat. J/MNRAS/484/3691
(End) Ana Fiallos [CDS] 16-May-2023