OCRA: the One Centimetre Receiver Array Mike Peel Jodrell Bank - PowerPoint PPT Presentation

OCRA: the One Centimetre Receiver Array Mike Peel Jodrell Bank Centre for Astrophysics, University of Manchester On behalf of the OCRA collaboration

Collaboration • Torun Centre for Astronomy Roman Feiler, Dr Marcin Gawronski, Dr Bartosz Lew, Prof. Andrzej Kus, Bogna Pazderska, Eugeniusz Pazderski, Dr Boud Roukema • University of Bristol Abdulaziz Alareedh, Prof. Mark Birkinshaw, (Dr Katy Lancaster) • University of Manchester Dr Richard Battye, Prof. Ian Browne, Prof. Richard Davis, Dr Mike Peel, Prof. Peter Wilkinson, (Dr Stuart Lowe) • Jodrell Bank Observatory (engineering) Colin Baines, Eddie Blackhurst, John Edgley, Dr Danielle Kettle, John Kitching, Don Lawson, Jason Marshall, Neil Roddis, Frank Winder

OCRA Image credit: S. Lowe Image credit: M. Peel Image credit: M. Peel

OCRA observations Horns FEM Hybrid LNAs Phase switches Hybrid BEM LNAs BEM Filters Detectors Video amps Cross-scans of strong sources DAQ (over 150 mJy)

OCRA observations Cal On-offs of weak sources Integration on SZ sources (3-150mJy) (0.2-3mJy)

Radio source studies • Strong sample (293 sources): Lowe et al. (2007) , A&A, 474, 673, arXiv:0707.3368 “30 GHz flux density measurements of the Caltech-Jodrell flat- spectrum sources with OCRA-p” • Intermediate sample (605 sources at north Ecliptic pole): Peel et al. (2011) , MNRAS, 410, 2690, arXiv:1007.5242 “One Centimetre Receiver Array-prototype observations of the CRATES sources at 30 GHz” • Weak sample (121 sources; 57 > 5mJy - AMI 15GHz selection): Gawronski et al. (2010) , MNRAS, 406, 1853, arXiv:0909.1189 “30 GHz observations of sources in the Very Small Array fields”

Radio source studies • No unexpected source population found at 30GHz • 30GHz 10mJy source density 2.2 ± 0.4 deg -2 • Fewer flat spectrum sources at low 30GHz flux density (more steep spectrum) • Number of GPS sources identified 42 in CJF sample 38 + 29 possibles in CRATES sample • Variable sources (J1849+6705, J1852+4855, J2006+6424 increased more than a factor of 2; J0954+7435 down by factor of 7) • Clear Eddington bias in WMAP source catalogue • Strong Gamma ray-Radio correlation (best to date?)

Radio source studies 10 Number of sources in bin (complete at 15GHz) 10 8 WMAP flux density [Jy] 6 1 4 2 0.1 0 0.1 1 10 -1.5 -1 -0.5 0 0.5 1 OCRA CRATES flux density [Jy] Spectral index between 1.4 and 30 GHz 50 1e-10 Fermi photon flux density [photon/cm 2 /MeV/s] 40 1e-11 Number of sources in bin 30 1e-12 ρ =0.71 1e-13 20 agn agu 1e-14 10 bzb bzq other Best fit line 1e-15 0 10 100 1000 10000 -1.5 -1 -0.5 0 0.5 1 30GHz flux density [mJy] Spectral index between 1.4 and 33 GHz

Planetary nebulæ • Pazderska et al. (2009) , A&A, 498, 463, arXiv:0902.3945 “Survey of planetary nebulae at 30 GHz with OCRA-p” • 442 PNes observed; 93 detected at 30GHz • No evidence for anomalous microwave emission (AME) Only free-free emission needed to fit spectra to 30GHz (Subsample of 41 sources with sufficient ancillary data) S 30GHz 1 18 16 14 0.5 12 log(S obs /S mod ) 10 N 0 8 6 -0.5 4 2 0 -1 0 200 400 600 800 1000 1200 1400 1600 0 0.5 1 1.5 2 2.5 3 3.5 4 4.5 flux densities [mJy] log(T b )

SZ observations • Lancaster et al. (2007) , MNRAS, 378, 673, arXiv:0705.3336 “Preliminary Sunyaev-Zel'dovich observations of galaxy clusters with OCRA-p” Cl0016+16 MS0451.5-0305 1 1 • Observations of 0.9 0.9 0.8 0.8 4 clusters: 0.7 0.7 Fraction of points Fraction of points 0.6 0.6 CL0016, MS0541 0.5 0.5 0.4 0.4 MS1054, A2218 0.3 0.3 0.2 0.2 0.1 0.1 • Target Field Target Field Trail field Trail field All detected at 0 0 -0.1 -0.05 0 0.05 0.1 -0.1 -0.05 0 0.05 0.1 Double difference signal (microvolts) Double difference signal (microvolts) (a) Cl 0016+16 (b) MS 0451.6-0305 4-6 σ level in MS1054.4-0321 A2218 1.2 1 10.5-13.5 hours 0.9 1 0.8 0.7 0.8 Fraction of points Fraction of points 0.6 0.6 0.5 0.4 0.4 0.3 0.2 0.2 0.1 Target Field Target Field Trail field Trail field 0 0 -0.1 -0.05 0 0.05 0.1 -0.1 -0.05 0 0.05 0.1 Double difference signal (microvolts) Double difference signal (microvolts) (c) MS 1054.4-0321 (d) A2218

SZ observations • Lancaster et al. (2011) , MNRAS (submitted) “Sunyaev Zel’dovich observations of a statistically complete sample of galaxy clusters with OCRA-p” • 18 most X-ray luminous clusters at z>0.2 (ROSAT) 13 detected at >3 σ • SZ-X-ray scaling relations in good agreement with self-similar models • Sample will be extended to 33 clusters in future paper.

SZ observations 10 8 6 4 y 0 (x10 4 )/E(z) 2 10 8 6 Robust points S/N < 3 Source > 10mJy Fit, slope = 1.81 +/- 0.72 Self similar model, slope = 1.5 4 y 0 (x10 4 )/E(z) 8/5 4 6 8 10 T x /keV (a) X-ray temperature 2 10 Robust points 8 S/N < 3 Source > 10mJy Fit, slope = 0.65 +/- 0.21 6 Self similar, slope = 0.6 1 0.2 0.4 0.6 0.8 1 2 Y X /10 15 M sol keV y 0 (x10 4 )/E(z) 1/4 4 (c) Y X parameter 2 Robust points S/N < 3 Source > 10mJy Fit, slope = 0.77 +/- 0.21 Self similar model, slope = 0.75 1 2 3 L X /10 45 erg s -1 (b) X-ray luminosity

Transient sources • Eyers et al. (2009), MNRAS, 395, 1533 “Double radio peak and non-thermal collimated ejecta in RS Ophiuchi following the 2006 outburst” Incorporating OCRA-p monitoring of RS Oph. • ATels 2511 & 2905: “OCRA monitoring of V407 Cyg at 30GHz” • Observed V407 Cyg from Apr-Oct 2010 Peak at 50mJy in mid Jun • V407 Cyg was interesting as it also flared in gamma-ray ( Fermi ) • Others ongoing; e.g. B2 0619+33 (gamma-ray flare from blazar)

Transient sources V407 Cyg at 30GHz April 2010 October 2010

Transient sources B2 0619+33 at 30GHz Sept 2010 Jan 2011

Ongoing • Surveys of WMAP and Planck ERCSC sources • Fermi source monitoring • KNoWS follow-up / confirmation observations • Survey of Extragalactic Nuclear Spectral Energies (SENSE) • Transient source follow-up • Additional SZ observations • OCRA-F commissioning (taking rather longer than expected...) • Blind point source and SZ surveys • Mapping of extended surveys

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