The C-Band All-Sky survey (C-BASS)

Proceedings of the 53rd Rencontres de Moriond, Cosmology 2018 ARISF (2018) 137-140

A Taylor

The C-Band All-Sky survey (C-BASS) is an experiment to image the whole sky in intensity and polarization at 5 GHz. The primary aim of C-BASS is to provide low-frequency all-sky maps of the Galactic emission which will enable accurate component separation analysis of both existing and future CMB intensity and polarization imaging surveys. Here we present an overview of the experiment and an update on the current status of observations. We present simulation results showing the expected improvement in the recovery of CMB and foreground signals when including C-BASS data as an additional low-frequency channel, both for intensity and polarization. We also present preliminary results from the northern part of the sky survey.

The C-Band All-Sky Survey (C-BASS): total intensity point source detection over the northern sky

Monthly Notices of the Royal Astronomical Society Oxford University Press (2020) staa1572

R Grumitt, A Taylor, L Jew, ME Jones, C Dickinson, A Barr, R Cepeda-Arroita, H Chiang, S Harper, H Heilgendorff, JL Jonas, JP Leahy, J Leech, TJ Pearson, MW Peel, ACS Readhead, J Sievers

We present a point source detection algorithm that employs the second order Spherical Mexican Hat Wavelet filter (SMHW2), and use it on C-BASS northern intensity data to produce a catalogue of point sources. The SMHW2 allows us to filter the entire sky at once, avoiding complications from edge effects arising when filtering small sky patches. The algorithm is validated against a set of Monte Carlo simulations, consisting of diffuse emission, instrumental noise, and various point source populations. The simulated source populations are successfully recovered. The SMHW2 detection algorithm is used to produce a $4.76\,\mathrm{GHz}$ northern sky source catalogue in total intensity, containing 1729 sources and covering declinations $\delta\geq-10^{\circ}$. The C-BASS catalogue is matched with the GB6 and PMN catalogues over their common declinations. From this we estimate the $90\%$ completeness level to be approximately $630\,\mathrm{mJy}$, with a corresponding reliability of $95\%$, when applying a Galactic mask covering $20\%$ of the sky. We find the C-BASS and GB6/PMN flux density scales to be consistent with one another to within $3\%$. The absolute positional offsets of C-BASS sources from matched GB6/PMN sources peak at approximately $3.5\,\mathrm{arcmin}$.

Updated Design of the CMB Polarization Experiment Satellite LiteBIRD


H Sugai, PAR Ade, Y Akiba, D Alonso, K Arnold, J Aumont, J Austermann, C Baccigalupi, AJ Banday, R Banerji, RB Barreiro, S Basak, J Beall, S Beckman, M Bersanelli, J Borrill, F Boulanger, ML Brown, M Bucher, A Buzzelli, E Calabrese, FJ Casas, A Challinor, V Chan, Y Chinone, J-F Cliche, F Columbro, A Cukierman, D Curtis, P Danto, P de Bernardis, T de Haan, M De Petris, C Dickinson, M Dobbs, T Dotani, L Duband, A Ducout, S Duff, A Duivenvoorden, J-M Duval, K Ebisawa, T Elleflot, H Enokida, HK Eriksen, J Errard, T Essinger-Hileman, F Finelli, R Flauger, C Franceschet, U Fuskeland, K Ganga, J-R Gao, R Genova-Santos, T Ghigna, A Gomez, ML Gradziel, J Grain, F Grupp, A Gruppuso, JE Gudmundsson, NW Halverson, P Hargrave, T Hasebe, M Hasegawa, M Hattori, M Hazumi, S Henrot-Versille, D Herranz, C Hill, G Hilton, Y Hirota, E Hivon, R Hlozek, D-T Hoang, J Hubmayr, K Ichiki, T Iida, H Imada, K Ishimura, H Ishino, GC Jaehnig, M Jones, T Kaga, S Kashima, Y Kataoka, N Katayama, T Kawasaki, R Keskitalo, A Kibayashi, T Kikuchi, K Kimura, T Kisner, Y Kobayashi, N Kogiso, A Kogut, K Kohri, E Komatsu, K Komatsu, K Konishi, N Krachmalnicoff, CL Kuo, N Kurinsky, A Kushino, M Kuwata-Gonokami, L Lamagna, M Lattanzi, AT Lee, E Linder, B Maffei, D Maino, M Maki, A Mangilli, E Martinez-Gonzalez, S Masi, R Mathon, T Matsumura, A Mennella, M Migliaccio, Y Minami, K Mistuda, D Molinari, L Montier, G Morgante, B Mot, Y Murata, JA Murphy, M Nagai, R Nagata, S Nakamura, T Namikawa, P Natoli, S Nerval, T Nishibori, H Nishino, Y Nomura, F Noviello, C O'Sullivan, H Ochi, H Ogawa, H Ogawa, H Ohsaki, I Ohta, N Okada, N Okada, L Pagano, A Paiella, D Paoletti, G Patanchon, F Piacentini, G Pisano, G Polenta, D Poletti, T Prouve, G Puglisi, D Rambaud, C Raum, S Realini, M Remazeilles, G Roudil, JA Rubino-Martin, M Russell, H Sakurai, Y Sakurai, M Sandri, G Savini, D Scott, Y Sekimoto, BD Sherwin, K Shinozaki, M Shiraishi, P Shirron, G Signorelli, G Smecher, P Spizzi, SL Stever, R Stompor, S Sugiyama, A Suzuki, J Suzuki, E Switzer, R Takaku, H Takakura, S Takakura, Y Takeda, A Taylor, E Taylor, Y Terao, KL Thompson, B Thorne, M Tomasi, H Tomida, N Trappe, M Tristram, M Tsuji, M Tsujimoto, C Tucker, J Ullom, S Uozumi, S Utsunomiya, J Van Lanen, G Vermeulen, P Vielva, F Villa, M Vissers, N Vittorio, F Voisin, I Walker, N Watanabe, I Wehus, J Weller, B Westbrook, B Winter, E Wollack, R Yamamoto, NY Yamasaki, M Yanagisawa, T Yoshida, J Yumoto, M Zannoni, A Zonca

Resolved observations at 31 GHz of spinning dust emissivity variations in rho Oph


C Arce-Tord, M Vidal, S Casassus, M Carcamo, C Dickinson, BS Hensley, R Genova-Santos, JR Bond, ME Jones, ACS Readhead, AC Taylor, JA Zensus

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 (OUP) (2019)

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

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


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

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


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 state-of-play of Anomalous Microwave Emission (AME) research

New Astronomy Reviews Elsevier (2018)

BT Draine, R Génova-Santos, Harper, B Hensley, JR Hill-Valler, T Hoang, FP Israel, L Jew, A Lazarian, JP Leahy, J Leech, CH López-Carabello, I McDonald, EJ Murphy, T Onaka, R Paladini, MW Peel, Y Perrott, F Poidevin, ACS Readhead, J-A Rubiño-Martín, AC Taylor, CT Tibbs, M Todorovic, M Vidal

Anomalous Microwave Emission (AME) is a component of diffuse Galactic radiation observed at frequencies in the range ≈10–60 GHz. AME was first detected in 1996 and recognised as an additional component of emission in 1997. Since then, AME has been observed by a range of experiments and in a variety of environments. AME is spatially correlated with far-IR thermal dust emission but cannot be explained by synchrotron or free–free emission mechanisms, and is far in excess of the emission contributed by thermal dust emission with the powerlaw opacity consistent with the observed emission at sub-mm wavelengths. Polarization observations have shown that AME is very weakly polarized ( ≲ 1 %). The most natural explanation for AME is rotational emission from ultra-small dust grains (“spinning dust”), first postulated in 1957. Magnetic dipole radiation from thermal fluctuations in the magnetization of magnetic grain materials may also be contributing to the AME, particularly at higher frequencies ( ≳ 50 GHz). AME is also an important foreground for Cosmic Microwave Background analyses. This paper presents a review and the current state-of-play in AME research, which was discussed in an AME workshop held at ESTEC, The Netherlands, June 2016.

A Herschel Space Observatory Spectral Line Survey of Local Luminous Infrared Galaxies from 194 to 671 Microns


N Lu, Y Zhao, T Diaz-Santos, C Kevin Xu, Y Gao, L Armus, KG Isaak, JM Mazzarella, PP van der Werf, PN Appleton, V Charmandaris, AS Evans, J Howell, K Iwasawa, J Leech, S Lord, AO Petric, GC Privon, DB Sanders, B Schulz, JA Surace

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


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


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>



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



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