Publications
Radio Surveys
Radio astronomy surveys since the 1950s have significantly advanced our understanding of celestial objects and cosmic phenomena. These surveys, conducted by observatories worldwide—including Jodrell Bank, Green Bank, Parkes, Arecibo, VLA, Molonglo, GMRT, LOFAR, and SKA—have cataloged vast numbers of radio sources, pulsars, and neutral hydrogen regions across the electromagnetic spectrum. Key contributions include the 3C survey from Cambridge, the Drift-Scan Survey for pulsars at Green Bank, and the extensive HI Parkes All-Sky Survey. Advanced projects like LOFAR's LoTSS, LOTAAS, and MSSS programs, along with SKA precursors (ASKAP, MWA, MeerKAT, HERA), have pushed boundaries in low-frequency radio observations, revealing new insights into radio galaxies, pulsars, and the structure of the universe. These surveys utilize cutting-edge telescopes and synthesis techniques to map the sky with unprecedented sensitivity and resolution.
Measuring pulsar profile variations with 2D Gaussian process regression
Researchers using advanced Gaussian process regression techniques have identified significant pulsar profile variations in 21 out of 26 observed pulsars, with 11 showing previously documented correlations to spin-down rates and seven exhibiting new evidence of such correlations. The study, conducted at Jodrell Bank Observatory, employed a computationally efficient 2D Gaussian process model to enhance sensitivity by simultaneously tracking time- and phase-correlated signals in pulsar magnetospheres. Notably, PSR B0740–28 displayed complex profile shape changes that switch between quasi-stable states, challenging current understanding of the underlying physical processes.
Observation of discontinuities in the periodic modulation of PSR B1828−11
Researchers at Jodrell Bank Observatory have identified discontinuities in the periodic modulation of PSR B1828−11, a radio pulsar, challenging previous explanations involving planetary companions or precession. The study, using a high-resolution dataset spanning over 500 days, found significant shifts in modulation amplitude, frequency, and phase occurring before a glitch—a sudden increase in rotation frequency. These changes are statistically supported with a Bayes factor of 1486, suggesting complex dynamics in the pulsar's magnetosphere or precession. The findings offer new insights into neutron star rotational behavior and rule out planetary companions as the sole cause of observed modulations.
RHINO: a large horn antenna for detecting the 21 cm global signal
RHINO, a novel experiment at Jodrell Bank Observatory, introduces a large horn antenna designed to detect the faint 21 cm global signal from neutral hydrogen, a critical probe of the intergalactic medium's thermal state during Cosmic Dawn and Reionization. The signal, measuring tens to hundreds of millikelvin, is spectrally smooth but challenging to isolate due to foreground radio emissions and instrumental noise. RHINO leverages the high characterizability and environmental shielding of horn antennas, alongside a continuous wave calibration source to monitor gain fluctuations without rapid switching. Initial simulations demonstrate its potential for recovering physical signal parameters despite bandwidth limitations. A scaled-down prototype is currently under construction, marking a significant step toward advancing our understanding of the early universe's thermal history.
A Cacophony of Echoes from Daily Monitoring of the Crab Pulsar at Jodrell Bank
Researchers analyzing archival data from the Jodrell Bank Observatory's 42-foot telescope have discovered that echoes—delayed pulses caused by intervening material redirecting emission toward Earth—are significantly more common than previously thought. These echoes, observed in the Crab pulsar's giant pulses between 2012 and 2016, suggest highly anisotropic structures with specific dimensions (lengths >4 au, widths ~0.1 au, depths ~5 au) likely originating from substructures within the nebular filaments of the Crab nebula. The study implies that such echoes may arise from offshoot features of larger nebular filaments, providing new insights into the pulsar's emission mechanisms and the surrounding environment.
Communications Satellites
A pioneering experiment in 1964 demonstrated the feasibility of using passive communications satellites to relay signals between distant locations, marking a significant milestone in global telecommunications. The study, conducted collaboratively by the U.S., USSR, and the University of Manchester's Jodrell Bank Observatory, involved transmitting signals from Jodrell Bank to Zimenki, Russia, via the Echo 2 satellite. Despite limitations such as the satellite's programmed altitude precluding simultaneous visibility between the U.S. and USSR, the experiment successfully established long-distance communication links, paving the way for future advancements in satellite-based telecommunications.
Cultural Heritage of Observatories
Astronomical observatories, though evolving in architecture and instruments, hold significant cultural heritage value. While their dynamic nature may preclude UNESCO World Heritage status, they can be recognized as 'Outstanding Astronomical Heritage' by the IAU for their scientific achievements. This study highlights the transformation of observatories from Baroque to modern designs, noting that their evolution reflects shifts from classical astronomy to astrophysics and beyond. Examples like La Plata and Hamburg observatories illustrate this transition, while contemporary structures such as the ESO Very Large Telescope or Jodrell Bank Observatory represent a departure from traditional dome shapes. The paper advocates for broadening UNESCO's Astronomy & World Heritage initiative to encompass broader scientific and technological heritage, including educational sites like the Gottorf Globe or Eise Eisinga Planetarium, which have played pivotal roles in science popularization.
Making an impact
A significant surge in student recruitment to physics and astronomy degrees, particularly at the University of Manchester, was attributed to the 'Cox Effect,' sparked by Professor Brian Cox's high-impact BBC science series. These programs, including 'Wonders of the Solar System' and 'Stargazing Live,' captivated global audiences, boosting the university's reputation and student applications. Jodrell Bank Observatory emerged as a central hub for astronomical outreach, further reinforced by its UNESCO World Heritage Site status and the annual bluedot festival. This study explores how media engagement, particularly through Cox's presentations, drove this educational impact.
Measuring glitch recoveries and braking indices with Bayesian model selection
Pulsars with large spin-up glitches typically exhibit braking indices greater than 3, indicating that internal torques dominate their rotational evolution between glitches. Researchers analyzed 157 glitches from 35 pulsars monitored by the Jodrell Bank Observatory using Bayesian model selection to determine post-glitch recovery parameters. They found strong correlations between glitch-induced spin-down rate changes and pulsar spin parameters, including a notable link between interglitch braking indices and spin-down rates. The study also suggests that the ratio of glitch-induced spin-down rate change to the second frequency derivative can estimate glitch recurrence times for certain pulsars. For younger pulsars (less than 10,000 years), external torques, such as electromagnetic dipole radiation, may dominate the observed braking indices, which could approach 3.
Observations of giant pulses from B0531+21 at the Institute of Applied Astronomy
A high-precision monitoring service for giant pulses from the Crab Nebula pulsar (B0531+21) has been established, achieving period determination accuracy comparable to global standards. Over 1.5 years of observations using RT-13 telescopes in Russia's Quasar-KVO network revealed that timing main pulses and interpulses separately yields a root mean square deviation of just 7 picoseconds—on par with Jodrell Bank Observatory's data. The study demonstrates the feasibility of domestic VLBI-based pulsar monitoring, leveraging specialized software for real-time ephemeris computation in S, X, and Ka bands.
SKAO telescope control system design and status
The Square Kilometre Array Observatory (SKAO) is developing a sophisticated Telescope Control System to manage its two cutting-edge radio telescope arrays, the SKA Low Frequency Telescope and the SKA Mid Frequency Telescope. Located in Western Australia and South Africa respectively, these telescopes will operate across a broad frequency range, from 50 MHz to 15 GHz, with up to 131,072 antennas and 197 dishes spanning vast distances. The control system is designed to support incremental development, enabling early functionality during construction to facilitate integration and verification of other systems. This paper provides an overview of the system's design patterns, technology choices, achievements, and lessons learned, highlighting its role in advancing astronomical observations and data processing capabilities.
Long Baseline Radar Bistatic Measurements of Geostationary Satellites
A novel approach to enhance the sensitivity of radar sensors for tracking geostationary satellites has been demonstrated using bistatic measurements. This method leverages large aperture radio telescopes as receivers, addressing the challenges posed by the extreme distance of 36,000 km and the small radar cross-section of modern satellites. The study successfully employed the Millstone Hill Radar (MHR) in the USA alongside three European receivers—the Sardinia Radio Telescope (SRT), Westerbork Synthesis Radio Telescope (WSRT), and Jodrell Bank Observatory (JBO)—to achieve long-baseline bistatic radar measurements. This technique offers a promising solution for improving the detection of small satellites in geosynchronous orbits, which are increasingly prevalent but difficult to track with conventional monostatic radar systems.
The specifics of pulsar radio emission
Pulsars exhibit highly stable periodic radio emissions, but observations reveal irregularities such as pulse timing variations, shape changes, emission switching, and rotation discontinuities. These phenomena are primarily attributed to magnetospheric processes. A notable finding is the confirmed link between radio pulse scattering and pulsar dispersion measure, observed through collaborative efforts at Jodrell Bank Observatory and Pushchino Radio Astronomy Observatory. The study suggests that these variations arise from pulsar eclipses by dense plasma clouds with electron density fluctuations far exceeding those in the interstellar medium. Additionally, it explores potential connections between glitches, pulse scattering, and gamma-ray flares, offering insights into complex pulsar behavior.
Diagnostics of interstellar medium parameters on non-discrete timing irregularities of pulsars
A strong correlation exists between interstellar medium (ISM) parameters—dispersion measure (DM) and rotation measure (RM)—and pulsar timing irregularities, with coefficients exceeding 0.60 in a large sample of Jodrell Bank Observatory radio pulsars. This finding suggests that ISM conditions significantly influence the stability and fluctuations observed in pulsar timing over decades. The study analyzed long-term timing data (spanning 40 years) to assess parameters such as timing activity, rotational stability, and fluctuation absorption, revealing consistent relationships between these metrics and DM/RM. These insights provide new diagnostic tools for understanding ISM effects on pulsar behavior.
Pulsar B0531 + 21 in the Crab Nebula
A strong correlation between the scattering time scale of radio pulses and the dispersion measure of pulsar B0531 + 21 in the Crab Nebula has been confirmed, providing deeper insights into the pulsar's plasma environment. Observations conducted at the Pushchino Radio Astronomy Observatory reveal that variations in pulse scattering are linked to dense plasma clouds eclipsing the pulsar, with electron density fluctuations far exceeding those in the interstellar medium. The study also explores potential connections between pulsar glitches, dispersion measure changes, radio pulse scattering, and gamma-ray flares, suggesting complex interactions within this dynamic astrophysical system.
Limits on absorption from a 332-MHz survey for fast radio bursts
A 58-day survey at Jodrell Bank Observatory using the Lovell Telescope at 332 MHz detected no fast radio bursts (FRBs), setting a 90% upper limit of 5,500 FRBs per day across the sky above a fluence threshold of 46 Jy ms. The study suggests that absorption, likely from a combination of Induced Compton Scattering and Free-Free Absorption, may explain the lack of detections at low frequencies (<800 MHz). Simulations indicate that these mechanisms could account for the non-detections, with electron density constraints aligning with expectations in superluminous supernovae environments. This research provides new insights into FRB absorption models and their potential progenitors.
On Strong Correlations between Timing Irregularities and Surface Magnetic Field of Rotation-Powered Pulsars
A strong correlation exists between timing irregularities and the surface magnetic field of rotation-powered pulsars, with pulsars exhibiting significant timing noise also showing up to five orders of magnitude higher magnetic fields. This finding emerges from an analysis of a large, homogeneous sample of pulsars observed at Jodrell Bank Observatory (JBO), combining data from the ATNF catalogue. Regression analysis revealed statistically significant correlations (r ≥ 0.80) between these parameters, suggesting a fundamental relationship that could deepen our understanding of pulsar behavior and magnetic field dynamics.
Operating the Square Kilometre Array: the world’s most data intensive telescope
The Square Kilometre Array (SKA), the world's largest radio observatory, will generate unprecedented data volumes when fully operational. This study outlines its operational model, highlighting challenges for globally distributed operations and workforce requirements for engineering maintenance. The SKA consists of two telescopes—one in Australia (50-350 MHz) and another in South Africa (0.35-15 GHz)—with Jodrell Bank Observatory serving as the global headquarters. Researchers modeled staffing needs to ensure efficient telescope operation, emphasizing collaboration with a network of Regional Centres to support scientific users. This work provides critical insights for managing one of the most data-intensive research infrastructures globally.
Spectrotemporal Analysis of a Sample of Bursts from FRB 121102
Researchers at Jodrell Bank Observatory have identified the shortest time separation between two individual fast radio bursts (FRBs) from FRB 121102, a repeating source of these mysterious cosmic signals. The study, using the Lovell telescope, detected a precursor burst just 17 milliseconds before the main burst, offering new insights into the spectrotemporal characteristics of FRBs. By analyzing a sample of bursts, the team compared their findings with data from other observatories, contributing to the broader understanding of these enigmatic phenomena. The study also provides open access to all detected bursts during this campaign, advancing research on the origin and behavior of repeating FRBs.
New long-term braking index measurements for glitching pulsars using a glitch-template method
Research at Jodrell Bank Observatory reveals that young glitching pulsars, including PSR B1800-21 and PSR B1823-13, exhibit long-term braking indices (n ≤ 2), suggesting they may be older than previously estimated. This challenges established evolutionary models by introducing a new trend in the P-P' diagram. The study employed a glitch-template method to mitigate timing noise and post-glitch recovery effects, enabling precise measurements for five pulsars, including updated data for Vela. Short-term inter-glitch braking indices (n_ig > 10) were also observed, indicating possible short-term re-coupling and long-term decoupling of superfluid dynamics in these stars. This work sheds light on the complex spin evolution of glitching pulsars and their potential connection to supernova remnants.
Neutron star glitches have a substantial minimum size
Neutron star glitches, sudden spin-up events that disrupt the steady slowdown of pulsars, exhibit a substantial minimum size, contrary to previous assumptions. Analyzing 29 years of daily observations from Jodrell Bank Observatory, researchers uncovered the full glitch size distribution for the Crab pulsar, revealing a rapid decline in smaller glitches below approximately 0.05 microhertz. This finding suggests that glitches involve the motion of billions of superfluid vortices and provides a new observable to identify their trigger mechanisms. Additionally, glitches were distinct from other rotational irregularities, supporting the notion that they originate differently from timing noise.
The Northern High Time Resolution Universe pulsar survey – I. Setup and initial discoveries
Scientists have discovered 15 new radio pulsars, including a rare millisecond pulsar with high eccentricity and a pulsar with a characteristic age of approximately 18,000 years, through the Northern High Time Resolution Universe (NHTRU) survey. This groundbreaking effort, conducted using the 100-meter Effelsberg radio telescope, marks the first comprehensive northern sky survey at high radio frequencies in two decades. The survey employs a novel 7-beam receiver system and advanced polyphase filterbank, enabling unprecedented sensitivity to millisecond pulsars and fast transients, particularly in dense galactic regions where previous surveys faced limitations due to dispersive smearing. By optimizing observation times based on Galactic latitude, the team has uncovered significant new astronomical data, including potential supernova remnant associations for one of the discovered pulsars.
A blind H i survey in the Ursa Major region★
A groundbreaking blind Hi survey, conducted using the Lovell Telescope at Jodrell Bank Observatory, uncovered 166 previously uncatalogued gas-rich objects in the Ursa Major region. This first-of-its-kind survey covered 480 square degrees and a velocity range from 300 to 1900 km/s, identifying Hi masses ranging from 10^7 to 10^10.5 solar masses. Notably, 10 of these detections were new, with optical counterparts identified for 99% of the sources. The study also highlighted a rare Hi source without an optical counterpart, confirmed through follow-up observations using the Green Bank Telescope. This research sheds light on the distribution and properties of gas-rich objects in the nearby spiral-rich Ursa Major region, providing insights into galaxy interactions and tidal dynamics.
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