scholarly journals Solar System Ephemerides, Pulsar Timing, Gravitational Waves, & Navigation

2017 ◽  
Vol 13 (S337) ◽  
pp. 150-153 ◽  
Author(s):  
T. Joseph W. Lazio ◽  
S. Bhaskaran ◽  
C. Cutler ◽  
W. M. Folkner ◽  
R. S. Park ◽  
...  
Keyword(s):  
Solar System ◽  
Gravitational Waves ◽  
Time Of Arrival ◽  
Millisecond Pulsars ◽  
The Past ◽  
The North ◽  
Spacecraft Navigation ◽  
Pulsar Timing ◽  
Multiple Spacecraft ◽  
The Times

AbstractIn-spiraling supermassive black holes should emit gravitational waves, which would produce characteristic distortions in the time of arrival residuals from millisecond pulsars. Multiple national and regional consortia have constructed pulsar timing arrays by precise timing of different sets of millisecond pulsars. An essential aspect of precision timing is the transfer of the times of arrival to a (quasi-)inertial frame, conventionally the solar system barycenter. The barycenter is determined from the knowledge of the planetary masses and orbits, which has been refined over the past 50 years by multiple spacecraft. Within the North American Nanohertz Observatory for Gravitational Waves (NANOGrav), uncertainties on the solar system barycenter are emerging as an important element of the NANOGrav noise budget. We describe what is known about the solar system barycenter, touch upon how uncertainties in it affect gravitational wave studies with pulsar timing arrays, and consider future trends in spacecraft navigation.

scholarly journals Pulsar timing array projects

2009 ◽  
Vol 5 (S261) ◽  
pp. 228-233
Author(s):  
G. Hobbs
Keyword(s):  
Solar System ◽  
Gravitational Waves ◽  
Time Scales ◽  
Direct Detection ◽  
Atomic Clocks ◽  
Millisecond Pulsars ◽  
Pulsar Timing ◽  
The Stability ◽  
Pulsar Timing Array ◽  
The Universe

AbstractPulsars are amongst the most stable rotators known in the Universe. Over many years some millisecond pulsars rival the stability of atomic clocks. Comparing observations of many such stable pulsars may allow the first direct detection of gravitational waves, improve the Solar System planetary ephemeris and provide a means to study irregularities in terrestrial time scales. Here we review the goals and status of current and future pulsar timing array projects.

scholarly journals The Parkes Pulsar Timing Array Project

2009 ◽  
Vol 5 (H15) ◽  
pp. 233-233
Author(s):  
R. N. Manchester
Keyword(s):  
Solar System ◽  
Gravitational Waves ◽  
Time Scale ◽  
Millisecond Pulsars ◽  
Pulsar Timing ◽  
Pulsar Timing Array

AbstractThe Parkes Pulsar Timing Array project is timing 20 millisecond pulsars with the aims of detecting gravitational waves, establishing a time scale based on pulsar periods and improving solar-system ephemerides.

scholarly journals Manipuri Lores: Folktales, Cultural History and Anthologies

2021 ◽  
Vol 7 (3) ◽  
pp. 140-143
Author(s):  
Yaisna Rajkumari ◽  
Keyword(s):  
Cultural History ◽  
Direct Link ◽  
The Past ◽  
The North ◽  
North Eastern ◽  
Indian State ◽  
History Of ◽  
The Times

The paper will establish a connection between folktales and the cultural history of a region, particularly with respect to the Indian state of Manipur. It is premised on the belief that a study of folktales can alert us not only to the various interconnections between folktales and the cultural history of a place but also help analyse the dynamics of the publication of the anthologies of folktales in relation to this cultural history. The paper will include analyses of Meitei and tribal tales pertaining to the nationalist phase and contemporary period in the history of the North Eastern Indian state of Manipur and look at how in the past few years, compilers and translators have incorporated versions of tales different from the earlier anthologies, establishing a direct link between the tales and the times of their publication.

scholarly journals The International Pulsar Timing Array: second data release

2019 ◽  
Vol 490 (4) ◽  
pp. 4666-4687 ◽  
Author(s):  
B B P Perera ◽  
M E DeCesar ◽  
P B Demorest ◽  
M Kerr ◽  
L Lentati ◽  
...  
Keyword(s):  
Gravitational Waves ◽  
High Precision ◽  
Noise Analysis ◽  
Low Frequency ◽  
The North ◽  
Pulsar Timing ◽  
Data Release ◽  
Timing Data ◽  
Noise Models ◽  
Pulsar Timing Array

ABSTRACT In this paper, we describe the International Pulsar Timing Array second data release, which includes recent pulsar timing data obtained by three regional consortia: the European Pulsar Timing Array, the North American Nanohertz Observatory for Gravitational Waves, and the Parkes Pulsar Timing Array. We analyse and where possible combine high-precision timing data for 65 millisecond pulsars which are regularly observed by these groups. A basic noise analysis, including the processes which are both correlated and uncorrelated in time, provides noise models and timing ephemerides for the pulsars. We find that the timing precisions of pulsars are generally improved compared to the previous data release, mainly due to the addition of new data in the combination. The main purpose of this work is to create the most up-to-date IPTA data release. These data are publicly available for searches for low-frequency gravitational waves and other pulsar science.

scholarly journals High-Precision Timing of Millisecond Pulsars and Precision Astrometry

1995 ◽  
Vol 166 ◽  
pp. 163-171 ◽  
Author(s):  
V. M. Kaspi
Keyword(s):  
Solar System ◽  
High Precision ◽  
Reference Frames ◽  
Millisecond Pulsar ◽  
Millisecond Pulsars ◽  
Pulsar Timing ◽  
Solar System Objects ◽  
Optical Reference ◽  
Precision Astrometry

We present the technique of long-term, high-precision timing of millisecond pulsars as applied to precision astrometry. We provide a tutorial on pulsars and pulsar timing, as well as up-to-date results of long-term timing observations of two millisecond pulsars, PSRs B1855+09 and B1937+21. We consider the feasibility of tying the extragalactic and optical reference frames to that defined by solar system objects, and we conclude that precision astrometry from millisecond pulsar timing has a bright future.

scholarly journals Pulsar Timing Arrays: Status and Techniques

2012 ◽  
Vol 8 (S291) ◽  
pp. 165-170 ◽  
Author(s):  
George Hobbs
Keyword(s):  
Solar System ◽  
Gravitational Waves ◽  
Quality Data ◽  
Data Sets ◽  
High Quality ◽  
High Quality Data ◽  
Pulsar Timing ◽  
Time Standard ◽  
Near Future

AbstractThree pulsar timing arrays are now producing high quality data sets. As reviewed in this paper, these data sets are been processed to 1) develop a pulsar-based time standard, 2) search for errors in the solar system planetary ephemeris and 3) detect gravitational waves. It is expected that the data sets will significantly improve in the near future by combining existing observations and by using new telescopes.

scholarly journals Pulsar Timing at the Deep Space Network

2016 ◽  
Vol 05 (04) ◽  
pp. 1641013 ◽  
Author(s):  
J. Kocz ◽  
W. Majid ◽  
L. White ◽  
L. Snedeker ◽  
M. Franco
Keyword(s):  
Space Station ◽  
Time Of Arrival ◽  
Deep Space ◽  
Short Term ◽  
Deep Space Network ◽  
Millisecond Pulsars ◽  
Space Network ◽  
Pulsar Timing ◽  
Initial Results

The 70-m DSN’s Deep Space Station antenna 14 (DSS-14) at Goldstone has recently been outfitted with instrumentation to enable pulsar searching and timing operation. Systems capable of similar operations are undergoing installation at DSS-63, and are planned for DSS-43. The Goldstone system is the first of these to become operational with a 640[Formula: see text]MHz bandwidth stretching from 1325–1965[Formula: see text]MHz. Initial results from the pulsar timing pipeline show short-term residuals of [Formula: see text][Formula: see text]ns for pulsar B1937+21. Commissioning observations at DSS-14 to obtain a baseline set of time of arrival (TOA) measurements on several millisecond pulsars (MSPs) are currently underway.

scholarly journals Pulsars and solar-system ephemerides

1996 ◽  
Vol 172 ◽  
pp. 105-112
Author(s):  
J.F. Chandler
Keyword(s):  
Solar System ◽  
Time Of Arrival ◽  
Lunar Laser Ranging ◽  
Basic Part ◽  
Orbital Parameters ◽  
Long Span ◽  
Long Run ◽  
Pulsar Timing ◽  
Timing Data ◽  
Spacecraft Tracking

The analysis of pulsar time-of-arrival data is intimately bound up with planetary ephemerides. Highly accurate ephemerides are required for Earth and Moon and, to a lesser degree, for the other planets, in order to make full use of the timing data for millisecond-class pulsars. These data, in turn, present an opportunity for improving planetary ephemerides in a variety of ways. Fitting the Earth and Moon orbital parameters to the timing data is the obvious first step, though it is less valuable in the short term for many applications than using the current accumulation of spacecraft-tracking and lunar laser ranging data. By themselves, the pulsar timing data convey no information on the orientation of Earth's orbit, since each pulsar's position on the sky must be determined from those same data. However, independent pulsar position measurements by VLBI, in combination with the timing-derived positions, can serve to fix the orientation of Earth's orbit with respect to the radio reference frame and thereby link the planetary and radio frames. In the long run, the acquisition of timing data over increasing time spans and with improving precision should prove to be an important factor in determining the shape, as well as the orientation, of Earth's orbit. In addition, pulsar timing over a sufficiently long span can directly measure a planet mass through the reaction of the rest of the solar system. The effect must be observed for a major fraction of the orbital period of the planet in question so that the signature can be separated from that of the ordinary spin-down of each pulsar. Finally, pulsar timing can be used to probe gravitational physics, a field with far-reaching consequences and a basic part of the framework for constructing the ephemerides.

scholarly journals Pulsar timing with the DFB at Nanshan

2012 ◽  
Vol 8 (S291) ◽  
pp. 574-576
Author(s):  
J. P. Yuan ◽  
N. Wang ◽  
Z. Y. Liu ◽  
J. B. Wang
Keyword(s):  
Radio Telescope ◽  
Gamma Ray ◽  
Millisecond Pulsars ◽  
The Past ◽  
Pulsar Timing

AbstractPulsar timing observations are being carried out with the Nanshan 25-metre radio telescope since 2000. We observe about 300 pulsars, including nine millisecond pulsars, at 1.5 GHz with a cryogenic receiver and digital filterbank. Frequent observations at Nanshan revealed 50 glitches. We detect nine more glitches in the past two years. Timing solutions obtained with the Nanshan telescope for eight radio loud Gamma ray pulsars are presented.

scholarly journals Timing of binary pulsars and the search for the low-frequency gravitational waves

2009 ◽  
Vol 5 (H15) ◽  
pp. 234-234
Author(s):  
Vladimir A. Potapov ◽  
Sergei M. Kopeikin
Keyword(s):  
Gravitational Waves ◽  
Standard Procedure ◽  
Low Frequency ◽  
Correlated Noise ◽  
Binary Pulsars ◽  
Stochastic Fluctuations ◽  
Pulsar Timing ◽  
Timing Data ◽  
Long Time ◽  
The Times

AbstractMillisecond and binary pulsars are the most stable natural standards of astronomical time giving us a unique opportunity to search for gravitational waves (GW) and to test General Relativity. GWs from violent events in early Universe and from the ensemble of galactic and extragalactic objects perturb propagation of radio pulses from a pulsar to observer bringing about stochastic fluctuations in the times of arrival of the pulses (TOA). If one observes the pulsar over a sufficiently long time span, the fluctuations will be registered as a low-frequency, correlated noise affecting the timing residuals in the frequency range 10−12 ÷ 10−7 Hz. This work demonstrates how the standard procedure of processing of the pulsar timing data can bias the estimate of the upper limit on the density of the GW background (GWB).

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