Publications by Michael Jones


Permittivity and permeability of epoxy-magnetite powder composites at microwave frequencies

Journal of Applied Physics 127 (2020)

M Zannoni, T Ghigna, M Jones, A Simonetto

© 2020 Author(s). Radio, millimeter, and sub-millimeter astronomy experiments as well as remote sensing applications often require castable absorbers with well known electromagnetic properties to design and realize calibration targets. In this context, we fabricated and characterized two samples using different ratios of two easily commercially available materials: epoxy (Stycast 2850FT) and magnetite (F e 3 O 4) powder. We performed transmission and reflection measurements from 7 GHz up to 170 GHz with a vector network analyzer equipped with a series of standard horn antennas. Using an empirical model, we analyzed the data to extract complex permittivity and permeability from transmission data; then, we used reflection data to validate the results. In this paper, we present the sample fabrication procedure, analysis method, parameter extraction pipeline, and results for two samples with different epoxy-powder mass ratios.


The C-Band All-Sky Survey (C-BASS): constraining diffuse Galactic radio emission in the North Celestial Pole region

Monthly Notices of the Royal Astronomical Society Oxford University Press 485 (2019) 2844–2860-

C Dickinson, A Barr, HC Chiang, C Copley, RDP Grumitt, HM Heilgendorff, LRP Jew, JL Jonas, ME Jones, JP Leahy, J Leech, EM Leitch, SJC Muchovej, TJ Pearson, MW Peel, ACS Readhead, J Sievers, MA Stevenson, A Taylor

The C-Band All-Sky Survey (C-BASS) is a high sensitivity all-sky radio survey at an angular resolution of 45 arcmin and a frequency of 4.7 GHz. We present a total intensity map of the North Celestial Pole (NCP) region of sky, above declination >+80°, which is limited by source confusion at a level of ≈0.6 mK rms. We apply the template-fitting (cross-correlation) technique to WMAP and Planck data, using the C-BASS map as the synchrotron template, to investigate the contribution of diffuse foreground emission at frequencies ∼20–40 GHz. We quantify the anomalous microwave emission (AME) that is correlated with far-infrared dust emission. The AME amplitude does not change significantly (⁠<10 per cent⁠) when using the higher frequency C-BASS 4.7 GHz template instead of the traditional Haslam 408 MHz map as a tracer of synchrotron radiation. We measure template coefficients of 9.93 ± 0.35 and 9.52±0.34 K per unit τ353 when using the Haslam and C-BASS synchrotron templates, respectively. The AME contributes 55±2μK rms at 22.8 GHz and accounts for ≈60 per cent of the total foreground emission. Our results show that a harder (flatter spectrum) component of synchrotron emission is not dominant at frequencies ≳5 GHz; the best-fitting synchrotron temperature spectral index is β = −2.91 ± 0.04 from 4.7 to 22.8 GHz and β = −2.85 ± 0.14 from 22.8 to 44.1 GHz. Free–free emission is weak, contributing ≈7μK rms (⁠≈7 per cent⁠) at 22.8 GHz. The best explanation for the AME is still electric dipole emission from small spinning dust grains.


The C-Band All-Sky Survey (C-BASS): Simulated parametric fitting in single pixels in total intensity and polarization

Monthly Notices of the Royal Astronomical Society Oxford University Press 490 (2019) 2958–2975-

L Jew, AC Taylor, M Jones, A Barr, HC Chiang, C Dickinson, RDP Grumitt, HM Heilgendorff, J Hill-Valler, JL Jonas, JP Leahy, J Leech, TJ Pearson, MW Peel, ACS Readhead, J Sievers

The cosmic microwave background (CMB) B-mode signal is potentially weaker than the diffuse Galactic foregrounds over most of the sky at any frequency. A common method of separating the CMB from these foregrounds is via pixel-based parametric-model fitting. There are not currently enough all-sky maps to fit anything more than the most simple models of the sky. By simulating the emission in seven representative pixels, we demonstrate that the inclusion of a 5 GHz data point allows for more complex models of low-frequency foregrounds to be fitted than at present. It is shown that the inclusion of the C-BASS data will significantly reduce the uncertainties in a number of key parameters in the modelling of both the galactic foregrounds and the CMB. The extra data allow estimates of the synchrotron spectral index to be constrained much more strongly than is presently possible, with corresponding improvements in the accuracy of the recovery of the CMB amplitude. However, we show that to place good limits on models of the synchrotron spectral curvature will require additional low-frequency data.


The C-Band All-Sky Survey (C-BASS): digital backend for the northern survey

Monthly Notices of the Royal Astronomical Society Oxford University Press 484 (2019) 5377–5388-

MA Stevenson, TJ Pearson, M Jones, CJ Copley, C Dickinson, JJ John, OG King, SJC Muchovej, A Taylor

The C-Band All-Sky Survey (C-BASS) is an all-sky full-polarization survey at a frequency of 5 GHz, designed to provide data complementary to the all-sky surveys of WMAP and Planck and future CMB B-mode polarization imaging surveys. We describe the design and performance of the digital backend used for the northern part of the survey. In particular, we describe the features that efficiently implement the demodulation and filtering required to suppress contaminating signals in the time-ordered data, and the capability for real-time correction of detector non-linearity and receiver balance.


Gain stabilization for radio intensity mapping using a continuous-wave reference signal

Monthly Notices of the Royal Astronomical Society Oxford University Press 489 (2019) 548-554

A Pollak, CM Holler, ME Jones, AC Taylor

Stabilizing the gain of a radio astronomy receiver is of great importance for sensitive radio intensity mapping. In this paper we discuss a stabilization method using a continuous-wave reference signal injected into the signal chain and tracked in a single channel of the spectrometer to correct for the gain variations of the receiver. This method depends on the fact that gain fluctuations of the receiver are strongly correlated across the frequency band, which we can show is the case for our experimental set-up. This method is especially suited for receivers with a digital back-end with high spectral resolution and moderate dynamic range. The sensitivity of the receiver is unaltered except for one lost frequency channel. We present experimental results using a new 4–8.5 GHz receiver with a digital back-end that shows substantial reduction of the 1/f noise and the 1/f knee frequency.


A compact quad-ridge orthogonal mode transducer with wide operational bandwidth

IEEE Antennas and Wireless Propagation Letters Institute of Electrical and Electronics Engineers 17 (2018) 422-425

A Pollak, ME Jones

We present the design and the measured performance of a compact quad-ridge orthomode transducer (OMT) operating in C-band with more than 100% fractional bandwidth. The OMT comprises two sets of identical orthogonal ridges mounted in a circular waveguide. The profile of these ridges was optimised to reduce significantly the transition length, while retaining the wide operational bandwidth of the quad-ridge OMT. In this letter, we show that the optimised compact OMT has better than -15dB return loss with the cross-polarisation well below -40dB in the designated 4.0-8.5GHz band.


The C-Band All-Sky Survey (C-BASS): design and capabilities

Monthly Notices of the Royal Astronomical Society Oxford University Press 480 (2018) 3224–3242-

M Jones, A Taylor, M Aich, CJ Copley, HC Chiang, RJ Davis, C Dickinson, R Grumitt, Y Hafez, HM Heilgendorff, CM Holler, MO Irfan, L Jew, J John, J Jonas, OG King, JP Leahy, J Leech, EM Leitch, SJC Muchovej, TJ Pearson, MW Peel, ACS Readhead, J Sievers, MA Stevenson

The C-Band All-Sky Survey (C-BASS) is an all-sky full-polarization survey at a frequency of 5 GHz, designed to provide complementary data to the all-sky surveys of WMAP and Planck, and future CMB B-mode polarization imaging surveys. The observing frequency has been chosen to provide a signal that is dominated by Galactic synchrotron emission, but suffers little from Faraday rotation, so that the measured polarization directions provide a good template for higher frequency observations, and carry direct information about the Galactic magnetic field. Telescopes in both northern and southern hemispheres with matched optical performance are used to provide all-sky coverage from a ground-based experiment. A continuous-comparison radiometer and a correlation polarimeter on each telescope provide stable imaging properties such that all angular scales from the instrument resolution of 45 arcmin up to full sky are accurately measured. The northern instrument has completed its survey and the southern instrument has started observing. We expect that C-BASS data will significantly improve the component separation analysis of Planck and other CMB data, and will provide important constraints on the properties of anomalous Galactic dust and the Galactic magnetic field.


The STRIP instrument of the Large Scale Polarization Explorer: microwave eyes to map the Galactic polarized foregrounds

MILLIMETER, SUBMILLIMETER, AND FAR-INFRARED DETECTORS AND INSTRUMENTATION FOR ASTRONOMY IX 10708 (2018) ARTN 107081G

C Franceschet, S Realini, A Mennella, G Addamo, A Bau, PM Battaglia, M Bersanelli, B Caccianiga, S Caprioli, F Cavaliere, KA Cleary, F Cuttaia, F Del Torto, V Fafone, Z Farooqui, RTG Santos, TC Gaier, M Gervasi, T Ghigna, F Incardona, S Iovenitti, M Jones, P Kangaslahti, R Mainini, D Maino, M Maris, P Mena, R Molina, G Morgante, A Passerini, MDR Perez-de-Taoro, OA Peverini, F Pezzotta, C Pincella, N Reyes, A Rocchi, JAR Martin, M Sandri, S Sartor, M Soria, V Tapia, L Terenzi, M Tomasi, E Tommasi, DM Vigano, F Villa, G Virone, A Volpe, B Watkins, A Zacchei, M Zannoni


The Low Frequency Receivers for SKA1-Low: Design and Verification

2017 XXXIIND GENERAL ASSEMBLY AND SCIENTIFIC SYMPOSIUM OF THE INTERNATIONAL UNION OF RADIO SCIENCE (URSI GASS) (2017)

P Benthem, M Gerbers, JGB de Vaate, S Wijnholds, J Bast, T Booler, T Colgate, B Crosse, D Emrich, P Hall, B Juswardy, D Kenney, F Schlagenhaufer, M Sokolowski, A Sutinjo, D Ung, R Wayth, A Williams, M Alderighi, P Bolli, G Comoretto, A Mattana, J Monari, G Naldi, F Perini, G Pupillo, S Rusticelli, M Schiaffino, F Schilliro, A Aminei, R Chiello, M Jones, J Baker, R Bennett, R Halsall, G Kaligeridou, M Roberts, H Schnetler, J Abraham, EDL Acedo, A Faulkner, N Razavi-Ghods, D Cutajar, A DeMarco, A Magro, KZ Adami, IEEE


HIPSR: A digital signal processor for the Parkes 21-cm multibeam receiver

Journal of Astronomical Instrumentation World Scientific Publishing 5 (2016)

DC Price, L Staveley-Smith, M Bailes, E Carretti, A Jameson, M Jones, W van Straten, SW Schediwy

HIPSR (HI-Pulsar) is a digital signal processing system for the Parkes 21-cm Multibeam Receiver that provides larger instantaneous bandwidth, increased dynamic range, and more signal processing power than the previous systems in use at Parkes. The additional computational capacity enables finer spectral resolution in wideband HI observations and real-time detection of Fast Radio Bursts during pulsar surveys. HIPSR uses a heterogeneous architecture, consisting of FPGA-based signal processing boards connected via high-speed Ethernet to high performance compute nodes. Low-level signal processing is conducted on the FPGA-based boards, and more complex signal processing routines are conducted on the GPU-based compute nodes. The development of HIPSR was driven by two main science goals: to provide large bandwidth, high-resolution spectra suitable for 21-cm stacking and intensity mapping experiments; and to upgrade the Berkeley–Parkes–Swinburne Recorder (BPSR), the signal processing system used for the High Time Resolution Universe (HTRU) Survey and the Survey for Pulsars and Extragalactic Radio Bursts (SUPERB).


Observations of Galactic star-forming regions with the Cosmic Background Imager at 31 GHz

MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY 453 (2015) 2082-2093

C Demetroullas, C Dickinson, D Stamadianos, SE Harper, K Cleary, ME Jones, TJ Pearson, ACS Readhead, AC Taylor


C-Band All-Sky Survey: a first look at the Galaxy

Monthly Notices of the Royal Astronomical Society Oxford University Press 448 (2015) 3572-3586

MO Irfan, C Dickinson, RD Davies, C Copley, RJ Davis, P Ferreira, CM Holler, JL Jonas, M Jones, OG King, JP Leahy, J Leech, EM Leitch, SJC Muchovej, TJ Pearson, MW Peel, ACS Readhead, MA Stevenson, D Sutton, A Taylor, J Zuntz

<p style="text-align:justify;"> We present an analysis of the diffuse emission at 5 GHz in the first quadrant of the Galactic plane using two months of preliminary intensity data taken with the C-Band All-Sky Survey (C-BASS) northern instrument at the Owens Valley Radio Observatory, California. Combining C-BASS maps with ancillary data tomake temperature-temperature plots, we find synchrotron spectral indices of β = -2.65 ± 0.05 between 0.408 and 5 GHz and β = -2.72 ± 0.09 between 1.420 and 5 GHz for -10° &gt; |b| &gt; -4°, 20° &gt; l &gt; 40°. Through the subtraction of a radio recombination line free-free template, we determine the synchrotron spectral index in the Galactic plane (|b|&gt;4°) to be β =-2.56±0.07 between 0.408 and 5 GHz, with a contribution of 53±8 per cent from free-free emission at 5 GHz. These results are consistent with previous low-frequency measurements in the Galactic plane. By including C-BASS data in spectral fits, we demonstrate the presence of anomalous microwave emission (AME) associated with the HII complexes W43, W44 and W47 near 30 GHz, at 4.4Σ, 3.1Σ and 2.5Σ, respectively. The CORNISH (Co-Ordinated Radio 'N' Infrared Survey for High mass star formation) VLA 5-GHz source catalogue rules out the possibility that the excess emission detected around 30 GHz may be due to ultracompact HII regions. Diffuse AME was also identified at a 4Σ level within 30° &gt; l &gt; 40°, -2° &gt; b &gt; 2° between 5 and 22.8 GHz.</p>


THE Q/U IMAGING EXPERIMENT: POLARIZATION MEASUREMENTS OF THE GALACTIC PLANE AT 43 AND 95 GHz

ASTROPHYSICAL JOURNAL 811 (2015) ARTN 89

TM Ruud, U Fuskeland, IK Wehus, M Vidal, D Araujo, C Bischoff, I Buder, Y Chinone, K Cleary, RN Dumoulin, A Kusaka, R Monsalve, SK Naess, LB Newburgh, RA Reeves, JTL Zwart, L Bronfman, RD Davies, R Davis, C Dickinson, HK Eriksen, T Gaier, JO Gundersen, M Hasegawa, M Hazumi, KM Huffenberger, ME Jones, CR Lawrence, EM Leitch, M Limon, AD Miller, TJ Pearson, L Piccirillo, SJE Radford, ACS Readhead, D Samtleben, M Seiffert, MC Shepherd, ST Staggs, O Tajima, KL Thompson, QUIET Collaboration


THE Q/U IMAGING EXPERIMENT: POLARIZATION MEASUREMENTS OF RADIO SOURCES AT 43 AND 95 GHz

ASTROPHYSICAL JOURNAL 806 (2015) ARTN 112

KM Huffenberger, D Araujo, C Bischoff, I Buder, Y Chinone, K Cleary, A Kusaka, R Monsalve, SK Naess, LB Newburgh, R Reeves, TM Ruud, IK Wehus, JTL Zwart, C Dickinson, HK Eriksen, T Gaier, JO Gundersen, M Hasegawa, M Hazumi, AD Miller, SJE Radford, ACS Readhead, ST Staggs, O Tajima, KL Thompson, QUIET Collaboration


Astronomical receiver modelling using scattering matrices

Monthly Notices of the Royal Astronomical Society Oxford University Press (OUP) 446 (2015) 1252-1267

OG King, ME Jones, C Copley, RJ Davis, JP Leahy, J Leech, SJC Muchovej, TJ Pearson, AC Taylor


Astronomical receiver modelling using scattering matrices

MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY 446 (2015) 1252-1267

OG King, ME Jones, C Copley, RJ Davis, JP Leahy, J Leech, SJC Muchovej, TJ Pearson, AC Taylor


The C-Band All-Sky Survey (C-BASS): design and implementation of the northern receiver

Monthly Notices of the Royal Astronomical Society Oxford University Press (OUP) 438 (2014) 2426-2439

OG King, ME Jones, EJ Blackhurst, C Copley, RJ Davis, C Dickinson, CM Holler, MO Irfan, JJ John, JP Leahy, J Leech, SJC Muchovej, TJ Pearson, MA Stevenson, AC Taylor


SKA synergy with microwave background studies

in , 9-13-June-2014 (2014)

C Burigana, P Alexander, C Baccigalupi, D Barbosa, A Blanchard, AD Rosa, G De Zotti, F Finelli, A Gruppuso, M Jones, S Matarrese, A Melchiorri, D Molinari, M Negrello, D Paoletti, F Perrotta, R Scaramella, T Trombetti

© Copyright owned by the author(s) under the terms of the Creative Commons Attribution-NonCommercial-ShareAlike Licence. The extremely high sensitivity and resolution of the Square Kilometre Array (SKA) will be useful for addressing a wide set of themes relevant for cosmology, in synergy with current and future cosmic microwave background (CMB) projects. Many of these themes also have a link with future optical-IR and X-ray observations. We discuss the scientific perspectives for these goals, the instrumental requirements and the observational and data analysis approaches, and identify several topics that are important for cosmology and astrophysics at different cosmic epochs.


The cosmic dawn and epoch of reionization with the square kilometre array

Proceedings of Science 9-13-June-2014 (2014)

LVE Koopmans, J Pritchard, G Mellema, F Abdalla, J Aguirre, K Ahn, R Barkana, I Van Bemmel, G Bernardi, A Bonaldi, F Briggs, AG De Bruyn, TC Chang, E Chapman, X Chen, B Ciardi, KK Datta, P Dayal, A Ferrara, A Fialkov, F Fiore, K Ichiki, IT Illiev, S Inoue, V Jelić, M Jones, J Lazio, U Maio, S Majumdar, KJ Mack, A Mesinger, MF Morales, A Parsons, UL Pen, M Santos, R Schneider, B Semelin, RS De Souza, R Subrahmanyan, T Takeuchi, C Trott, H Vedantham, J Wagg, R Webster, S Wyithe

© Copyright owned by the author(s) under the terms of the Creative Commons Attribution-NonCommercial-ShareAlike Licence. Concerted effort is currently ongoing to open up the Epoch of Reionization (z ∼15-6) for studies with IR and radio telescopes. Whereas IR detections have been made of sources (Lyman-a emitters, quasars and drop-outs) in this redshift regime in relatively small fields of view, no direct detection of neutral hydrogen, via the redshifted 21-cm line, has yet been established. Such a direct detection is expected in the coming years, with ongoing surveys, and could open up the entire universe from z ∼6-200 for astrophysical and cosmological studies, opening not only the Epoch of Reionization, but also its preceding Cosmic Dawn (z ∼30-15) and possibly even the later phases of the Dark Ages (z ∼200-30). All currently ongoing experiments attempt statistical detections of the 21-cm signal during the Epoch of Reionization, with limited signal-to-noise. Direct imaging, except maybe on the largest (degree) scales at lower redshifts, as well as higher redshifts will remain out of reach. The Square Kilometre Array (SKA) will revolutionize the field, allowing direct imaging of neutral hydrogen from scales of arc-minutes to degrees over most of the redshift range z ∼6-28 with SKA1-LOW, and possibly even higher redshifts with the SKA2-LOW. In this SKA will be unique, and in parallel provide enormous potential of synergy with other upcoming facilities (e.g. JWST). In this chapter we summarize the physics of 21-cm emission, the different phases the universe is thought to go through, and the observables that the SKA can probe, referring where needed to detailed chapters in this volume. This is done within the framework of the current SKA1 baseline design and a nominal CD/EoR straw-man survey, consisting of a shallow, medium-deep and deep survey, the latter probing down to ∼1mK brightness temperature on arc-minute scales at the end of reionization. Possible minor modifications to the design of SKA1 and the upgrade to SKA2 are discussed, in addition to science that could be done already during roll-out when SKA1 still has limited capabilities and/or core collecting area.


Increased SKA-Low Science Capability through Extended Frequency Coverage

SKA Organisation (2013) 149

DC Price, D Sinclair, J Hickish, ME Jones

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