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

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

Dec 12, 2023 169 likes •352 views

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

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OCRA: the One Centimetre Receiver Array

Mike Peel

Jodrell Bank Centre for Astrophysics, University of Manchester On behalf of the OCRA collaboration

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SLIDE 2

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

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SLIDE 3

OCRA

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

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SLIDE 4

OCRA observations

DAQ Horns Hybrid LNAs Phase switches Hybrid LNAs Filters Detectors Video amps FEM BEM BEM

Cross-scans of strong sources (over 150 mJy)

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SLIDE 5

OCRA observations

Cal

On-offs of weak sources

(3-150mJy)

Integration on SZ sources

(0.2-3mJy)

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SLIDE 6

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”

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SLIDE 7

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?)
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SLIDE 8

Radio source studies

2 4 6 8 10

  • 1.5
  • 1
  • 0.5

0.5 1 Number of sources in bin (complete at 15GHz) Spectral index between 1.4 and 30 GHz

10 20 30 40 50

  • 1.5
  • 1
  • 0.5

0.5 1 Number of sources in bin Spectral index between 1.4 and 33 GHz 1e-15 1e-14 1e-13 1e-12 1e-11 1e-10 10 100 1000 10000 Fermi photon flux density [photon/cm2/MeV/s] 30GHz flux density [mJy] agn agu bzb bzq

  • ther

Best fit line

ρ=0.71

0.1 1 10 0.1 1 10 WMAP flux density [Jy] OCRA CRATES flux density [Jy]

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SLIDE 9

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)

2 4 6 8 10 12 14 16 18 200 400 600 800 1000 1200 1400 1600 N flux densities [mJy] S30GHz

  • 1
  • 0.5

0.5 1 0.5 1 1.5 2 2.5 3 3.5 4 4.5 log(Sobs/Smod) log(Tb)

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SZ observations

  • Lancaster et al. (2007), MNRAS, 378, 673, arXiv:0705.3336

“Preliminary Sunyaev-Zel'dovich observations of galaxy clusters with OCRA-p”

  • Observations of

4 clusters: CL0016, MS0541 MS1054, A2218

  • All detected at

4-6σ level in 10.5-13.5 hours

0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1
  • 0.1
  • 0.05
0.05 0.1 Fraction of points Double difference signal (microvolts) Cl0016+16 Target Field Trail field

(a) Cl 0016+16

0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1
  • 0.1
  • 0.05
0.05 0.1 Fraction of points Double difference signal (microvolts) MS0451.5-0305 Target Field Trail field

(b) MS 0451.6-0305

0.2 0.4 0.6 0.8 1 1.2
  • 0.1
  • 0.05
0.05 0.1 Fraction of points Double difference signal (microvolts) MS1054.4-0321 Target Field Trail field

(c) MS 1054.4-0321

0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1
  • 0.1
  • 0.05
0.05 0.1 Fraction of points Double difference signal (microvolts) A2218 Target Field Trail field

(d) A2218

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SLIDE 11

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 >3σ

  • SZ-X-ray scaling relations in

good agreement with self-similar models

  • Sample will be extended to

33 clusters in future paper.

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SZ observations

2 4 6 8 10 4 6 8 10 y0(x104)/E(z) Tx/keV Robust points S/N < 3 Source > 10mJy Fit, slope = 1.81 +/- 0.72 Self similar model, slope = 1.5

(a) X-ray temperature

2 4 6 8 10 1 2 3 y0(x104)/E(z)1/4 LX/1045 erg s-1 Robust points S/N < 3 Source > 10mJy Fit, slope = 0.77 +/- 0.21 Self similar model, slope = 0.75

(b) X-ray luminosity

1 2 4 6 8 10 0.2 0.4 0.6 0.8 1 2 y0(x104)/E(z)8/5 YX/1015 Msol keV Robust points S/N < 3 Source > 10mJy Fit, slope = 0.65 +/- 0.21 Self similar, slope = 0.6

(c) YX parameter

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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)
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SLIDE 14

Transient sources

V407 Cyg at 30GHz

April 2010 October 2010

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SLIDE 15

Transient sources

Sept 2010 Jan 2011

B2 0619+33 at 30GHz

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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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SLIDE 17

Fun with foam...