Richard Norman (Dick) Manchester

The early years

Richard Norman (Dick) Manchester was born in Greymouth on the West Coast of New Zealand on 5 June 1942, but grew up in a small town, Waimate, in South Canterbury on the east coast of the South Island. He retains New Zealand citizenship but became an Australian citizen in 2008.

His early education was at Waimate Primary School and Waimate High School. In 1960, he began an Engineering course at the University of Canterbury, Christchurch with a studentship from the New Zealand Post Office. However, after one year, he decided that a career in science looked more interesting and, much to his banker father’s chagrin, but also support in the form of a loan, paid back in full the money provided by the studentship. He went on to graduate in 1964 with First-Class Honours in Physics, receiving the Haydon Prize in Physics in 1962 and becoming a Senior Scholar of the University of Canterbury in 1963. In 1964, he was awarded a prestigious Internal Postgraduate Scholarship by the University of Canterbury and began a PhD in the ionospheric research group led by the then Reader in Physics, Dr CD Ellyett.

In February 1965, Dr Ellyett was appointed Professor of Physics at the University of Newcastle, Australia, and took with him to Newcastle five members of his research group, including Dick as its junior member. On arriving in Australia, Dick changed research topics to study geomagnetic micropulsations – tiny fluctuations in the Earth’s magnetic field at frequencies of about 1 Hz. These are generated by solar disturbances in the outer magnetoshphere propagating down to the auroral zones and then to mid-latitude and equatorial regions. Dick had the idea that the propagation away from the auroral zones was in a duct or waveguide formed by the F₂ region of the ionosphere. With support from the University of Newcastle, he set up recording stations near Hobart and near Newcastle and showed that the propagation northward was at the expected Alfvén velocity and, furthermore, that the measured delays were correlated with f₀F₂, the F₂-region critical frequency, thereby proving the hypothesis.

He graduated with a PhD in Physics from the University of Newcastle in 1969. Not long after his arrival in Newcastle, Dick met Barbara A Nicholson, then a student in the Science Faculty. Barbara went on to complete a BSc with First-Class Honours in Mathematics and an MSc in Theoretical Physics. They were married in February 1967 and have three children.

Postdoctoral Studies at CSIRO

Toward the end of his PhD, Dick was pondering his future and decided to investigate a career in radio astronomy. His interest in astronomy, and radio astronomy in particular, had been sparked by various Christmas and birthday presents from his uncle, then a senior engineer with the New Zealand Electricity Department. Aware that the CSIRO had a great reputation in radio astronomy, he and Barbara arranged to visit John Bolton at Parkes in November 1967, to investigate the possibility of an overseas postdoctoral position in astronomy. John was not particularly encouraging on that possibility, but then offered him a job at Parkes (see also Parkes radio telescope construction).

In early 1968, the Parkes laboratory was to take delivery of its first computer, a PDP-9, and the bargain was that they would teach him astronomy if he programed the new computer, and so it turned out. Dick and Barbara moved to Parkes in February 1968, staying at the Bolton’s house for the first couple of months (since John and his wife Letty were overseas at the time), and looking after their 20-year-old cat ‘Sweetie Pie’ who would eat nothing but chopped lamb kidneys and 3-day-old curdled milk.

The computer was delivered in April 1969, and Dick wrote assembler-language routines for reading in basic parameters like the telescope position and universal and sidereal time. He also wrote the first program for recording and analysing telescope data, measuring the position and flux density of radio sources from scans through their position.

By coincidence, the date of Dick’s commencement at Parkes was just 12 days before the announcement in Nature of the discovery of the first pulsar. Although he was present in the telescope control room on March 8 1968, when the first pulsar recordings were made (the best of which featured on the original Australian $50 note along with the telescope itself), he didn’t get much involved with pulsar astronomy until February 1969 when he helped V Radhakrishnan make observations of the Vela pulsar. These observations formed the genesis of the so-called ‘rotating vector model’ for pulsars and resulted in the discovery of the first known pulsar ‘glitch’, a sudden decrease in the pulsar period by about a part in a million.

Postdoctoral and faculty appointments in the USA

In July 1969, he took up a postdoctoral fellowship at the National Radio Astronomy Observatory (NRAO) in Charlottesville, Virginia, where he followed up the interest triggered by the Parkes observations, making the first large-scale measurements of pulsar polarisation and Faraday rotation.

During his two years at NRAO, Dick began a collaboration with Joe Taylor and Richard Huguenin, both then at the University of Massachusetts in Amherst. This led to his appointment to a faculty position at the University of Massachusetts in 1971, where he remained until 1974.

Return to CSIRO

In 1974, Dick returned to take up a Senior Research Scientist position at the CSIRO Division of Radiophysics, then just relocated at Epping. He spent much of the first year or so completing the book Pulsars, written in collaboration with Joe Taylor and published in 1977. This was the first monograph on pulsars and was a highly cited reference work for more than 30 years.

From 1980 to 1987, he held the position of Leader, Astrophysics Group, Division of Radiophysics. In 1989, he was elected a Fellow of the Australian Academy of Science and was promoted to the level of Chief Research Scientist at the Australia Telescope National Facility, CSIRO. He has been a Guest Professor at Peking University, China since 1997, was a Professorial Associate, School of Physics, University of Melbourne (1997-2000), an Adjunct Professor at Sydney University since 2001 and an Honorary Professor at the National Astronomical Observatories, Urumqi, China, since 2002.

From 2003-08, he was an ARC Federation Fellow at the ATNF and was appointed a CSIRO Fellow in 2007. Although Dick formally retired from the CSIRO at the end of his Federation Fellowship in 2008, with his CSIRO Fellowship and the support of the ATNF, he has continued to fulfill his desire to remain active in astrophysical research and the development of radio-astronomical instrumentation.

Research career at CSIRO

Pulsar surveys

With his close colleague Andrew Lyne of the Jodrell Bank Observatory, Dick has led a long series of searches for pulsars using the Parkes radio telescope. As a result of these searches, the Parkes telescope has found about twice as many pulsars as the rest of the world’s telescopes combined, a remarkable achievement. The first of the large-scale pulsar searches was the Second Molonglo Survey (Manchester et al., 1978) which discovered 155 pulsars using both the Molonglo and Parkes instruments, more than doubling the number of pulsars known at the time. This was followed by the discovery of 10 millisecond pulsars in the globular cluster 47 Tucanae (Manchester et al., 1991) and the first high-frequency survey of the southern Galactic plane (Johnston et al., 1992) which discovered 46 pulsars. The Parkes Southern Pulsar Survey (Manchester et al., 1996; Lyne et al. 1998) covered the whole southern sky and discovered 101 pulsars, including the nearest and brightest millisecond pulsar known (PSR J0437-4715). These surveys were all very successful but have now been surpassed by the Parkes Multibeam Pulsar Survey (Manchester et al., 2001; Lorimer et al., 2006), by far the most successful pulsar survey ever. The Multibeam survey commenced in 1997 and has now discovered nearly 800 pulsars, giving a magnificent sample for many different studies of pulsar properties and application to other investigations such as studies of the Galactic magnetic field. Whole new classes of pulsar were discovered, for example, pulsars with magnetic field strengths comparable to those of magnetars and the ‘RRATs’, pulsars which are only detectable through individual strong pulses emitted at intervals of minutes to days.

Many interesting individual pulsars have been discovered in these surveys, but without doubt, the most significant is the double-pulsar system, PSR J0737-3039A/B, the first such system ever detected (Burgay et al., 2003; Lyne et al., 2004). Not only is this the first double pulsar ever discovered but, with an orbital period of just 2.4 hours, it is also by far the most relativistic binary pulsar known, making it an exceptional system for tests of gravitational theories. Already five different ‘post-Keplerian’ effects, i.e. effects which require general relativity or a similar gravitational theory for interpretation, have been detected. These confirm that general relativity is accurate at the 0.05% level, which is currently the most precise test in the regime of strong gravity (Kramer et al., 2006). PSR J0737-3039A/B has a merger timescale less than one third that of any other known system and this, combined with the fact that it is relatively near to us in the Galaxy, significantly increases the predicted detection rate of the merger events detectable by gravitational-wave observatories such as LIGO. The double-pulsar system has another unique aspect that makes it even more interesting. Because of interactions between the relativistic winds from the two pulsars, the pulses from the B pulsar are strongly modulated with orbital phase. Also, fortuitously, the orbit is seen nearly edge-on. For the first time it is possible to directly probe the magneto-ionic properties of pulsar magnetospheres, making possible studies of an extreme plasma physics environment that cannot be investigated in terrestrial laboratories (McLaughlin et al., 2004).

Evolving from the work on pulsar surveys, Dick and his group have established the Australia Telescope National Facility Pulsar Catalogue (Manchester et al., 2005). ATNF Pulsar Catalogue web interface allows access to a wide range of pulsar parameters, gives full bibliographic information and is internationally recognised as the best available pulsar catalogue.

Understanding pulsars

Dick has continued his interests in pulsar polarisation and its implications for the pulsar emission process. After returning to CSIRO in 1974 he collaborated with Peter McCulloch and Pip Hamilton of the University of Tasmania and Jon Ables of CSIRO Radiophysics on studies of pulsar polarisation. In the late 1980s these studies were continued in collaboration with colleagues from Peking University, initiating what has become a long-standing association with Chinese astronomers and astronomy. In 1988, he published with Andrew Lyne what has become a highly cited paper on pulsar polarisation and its implications for the beaming of radio emission from pulsars (Lyne & Manchester, 1988). More recently he has worked with Jinlin Han of the National Astronomical Observatories, Beijing, on studies of the Galactic magnetic field using observations of pulsar Faraday rotation (Han et al., 2006, 2018).

With the recent launch of the Fermi Gamma-ray Observatory, Dick has been involved in collaborations with the Fermi team, using Parkes radio timing data to enable searches for gamma-ray emission from known pulsars. The gamma-ray emission from pulsars and its relationship to the radio emission provides important diagnostics on conditions in the pulsar magnetosphere. A surprising result from this work is the detection of strong gamma-ray pulses from many millisecond pulsars.

The Parkes pulsar timing array project

In 2003, Dick was awarded an Australian Research Council Federation Fellowship. This enabled establishment of the Parkes Pulsar Timing Array (PPTA) project which has the principal goal of using precision timing of millisecond pulsars to make a direct detection of gravitational waves. Although the double-neutron-star binary systems provide strong evidence for the existence of gravitational waves, up to now there had been no direct detection of these waves despite many years of effort. PPTA data are also being used to look for instabilities in the terrestrial standard of time (which is based on a world-wide network of atomic clocks), to improve our knowledge of Solar-system objects, for example, the mass of Jupiter, and numerous other investigations. To achieve these goals will require timing of a large sample of millisecond pulsars with pulse time-of-arrival precisions of order 100 nanoseconds and data spans of at least 10 years. The project is a collaborative effort with contributions from scientists and engineers at the ATNF and from the group at Swinburne University led by Matthew Bailes. Gravitational wave bursts from the coalescence of binary black-hole systems and a double-neutron-star system have now been directly detected by the international LIGO-Virgo consortium (Abbott et al., 2016, 2017, 2018) leading to the establishment of a new branch of astrophysics. These signals have a very different origin to those that the pulsar timing arrays are sensitive to, and so the searches are largely complementary. The PPTA has achieved world-leading status in the quality and quantity of its data sets, leading to the publication of two paper in Science (Shannon et al., 2013, 2015) that set new limits on the strength of a gravitational-wave background from binary super-massive black holes in distant galaxies, thereby placing constraints on ideas about merging of galaxies and the formation and evolution of the super-massive black holes at their core.

International collaboration is an important aspect of the project. There are active collaborations with colleagues, especially Bill Coles from the University of California, San Diego, that add greatly to the theoretical and interpretative aspects of the project. In addition, the PPTA collaborates with similar projects in Europe (EPTA) and North America (NANOGrav) to form an International Pulsar Timing Array (IPTA), sharing data and resources to improve the ultimate sensitivity to gravitational waves and to help with achieving other goals.

Instrumental development

Right through his career in radio astronomy, Dick has had a strong interest in developing instrumentation to support his research objectives. This has included both the low-noise receivers used on telescopes and the signal processing systems used to record and analyse the data. He and colleague Andrew Lyne installed 88 new preamplifiers on the Molonglo radio telescope before undertaking the Second Molonglo Pulsar Survey. This more than doubled the sensitivity of the telescope for pulsar searches and enabled the discovery of 154 pulsars, more than doubling the number known at the time (1978). From the late 1990s, he led the development of the dual-band “10/50cm” receiver and the FPGA-based digital filter-bank systems, both of which were installed on the Parkes telescope in 2003. These systems have provided the backbone for the precision pulsar timing programs for the PPTA and the Double Pulsar, and also other pulsar studies such as investigations of pulse polarisation and scintillation. After 15 years of service, the 10/50cm receiver and the digital filter-banks are now being retired and replaced by the Ultra-Wideband receiver and signal-processing systems based on Graphics Processor Units (GPUs). Dick provided the conceptual design of the Ultra-Wideband receiver and has been a strong advocate for its development since 2011.

Other successes

From soon after his return to Australia in 1974, Dick was part of a small group advocating of the development of a synthesis array to complement the Parkes telescope. He was a member of the Design Study Group for the ‘Australian Synthesis Telescope’ from 1975 to 1981, Chairman of the Australia Telescope Scientific Objectives Committee/Users Committee from 1982 to 1991, and a member of the Australia Telescope Steering Committee from 1991 to 1995. He worked with Jon Ables at Parkes on development of the Two-Element Synthesis Telescope (TEST) from 1979 to 1982. TEST was designed mainly to test out ideas for a larger array, but it also produced useful science, mapping the neutral hydrogen and radio continuum in several galaxies.

The Australia Telescope Compact Array was ultimately funded in 1983 and completed in 1988. Dick initiated one of the first projects on the ATCA, a study of Supernova 1987a, the brightest supernova in more than 400 years. The supernova, which is located in the Large Magellanic Cloud, our nearest neighbour galaxy, has resulted in the formation of a supernova remnant as the debris from the explosion ploughs into the surrounding gas. With colleagues, Dick has used the Australia Telescope Compact Array to study the development of the radio remnant, including the first images at 12-mm wavelength which have comparable resolution to those obtained by the Hubble Space Telescope at optical wavelengths. He has also made many searches at both radio and optical wavelengths for a central pulsar in the remnant, so far without success.

Beginning with a first visit in 1986, Dick has a strong and continuing relationship with Chinese radio astronomy, supervising students, working with colleagues and assisting with instrumental development, initially at Peking University but subsequently with other groups in Beijing and groups in Shanghai and Guanzhou. In 1996, Dick began a collaboration with Urumqi Astronomical Observatory in Xinjiang Province, north-western China. He assisted in the development of a pulsar timing system at the Observatory and has since made roughly annual visits to work with colleagues and students on pulsar-related projects. In 2005, he served on an International Advisory Committee for the FAST radio telescope in China, the recently commissioned 500-m diameter reflector  in Guizhou Province. He continues to assist with development of the receiving systems for the telescope. He is also supporting the development of a large steerable telescope in Xinjiang, known as the QiTai Telescope, chairing international design study advisory groups in 2013 and 2017. In 2017, with a Xinjiang Observatory student and the Observatory Director (Dick’s ex-student Na Wang) he published a new model for the distribution of free electrons in the Galactic interstellar medium which is now a world standard for estimation of pulsar distances from the observed dispersion of their pulses.

Publications and mentoring

Dick has been a mentor to many students and younger colleagues over the years. He has co-supervised more than 20 PhD students, most of whom are now well established as astronomers, some leaders in their field.

He has an outstanding publication record, with more than 730 publications, including 470 in refereed journals. Many of his papers are highly cited, with more than 31,900 citations in total, and his Hirsch index is 90. He was named as an ISI Citation Laureate in 2001. He has given many invited talks and colloquia, including the Inaugural Hewish Lecture at the Cavendish Laboratory, Cambridge University in 2008 and a 2015 lecture in the Tsinghau University (Beijing) Distinguished Lectures in Astrophysics series.

Honours and awards

Dick Manchester has received many honours and awards for his contributions to radio astronomy. He was President of the Astronomical Society of Australia from 2001 to 2003, President of IAU Commission 31 Time from 2009 to 2012 and a member of the International Pulsar Timing Array Steering Committee from 2011 to 2013 and its Chair in 2012. Other honours and awards include:

Fellowships

Awards

Named lectures

Selected committee memberships

Source

• Manchester RN, 2009, Personal communication.