Early Science with AMI

Jonathan Zwartjtlz2@mrao.cam.ac.uk

19 March 2006 Jonathan Zwart, Cavendish Astrophysics 2

Overview

• Case Study: Abell 1914

• Observing strategy & science goals– Early cluster targets– Survey plans

19 March 2006 Jonathan Zwart, Cavendish Astrophysics 3

A1914: 228 Hours with Ryle

19 March 2006 Jonathan Zwart, Cavendish Astrophysics 4

A1914: 34 Hours with AMI

Long baselines Short baselines

(after radio sources removed)

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• Only 7 (/10) antennas

• 18 point sources subtracted Need for source subtraction

• astro-ph/0509215 (MNRAS accepted)

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Observing Strategy

• Known clusters

• Initial blind surveys

• Surveys of equatorial fields (need LA)

• Joint fields (AMiBA, SZA, UKIDSS…)

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Early Cluster Targets

• Abell (optical) & NORAS (X-ray)

• MACS (X-ray, Ebeling et al. 2000)

• High-z candidates

Ryle source survey (2004–):

4 days for each of ~ 100 ‘lucky’ targets

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NORAS-Selected Clusters

Selection criteria:– LX > 6.8×1044 erg s-1

– z > 0.1

Calibrate scaling relations L–T, M, etc

+X-ray g, H0

A263: 10 hours; z = 0.3; (Natasha Hurley-Walker)

19 March 2006 Jonathan Zwart, Cavendish Astrophysics 10

MACS-Selected Clusters

Selection criteria:– LX > 1045 erg s-1

– z > 0.5

Evolution of scaling relations with z

+X-ray g (z), H0, q0

MACS 0717+37: 8 hours; z = 0.545

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Blind Surveys

• ‘Wedding cake’:– 10 □° deep survey (1 year)– 100 □° shallow survey (6 months)

• Evolution of cluster population, N(m,z)

– Some experimenting with z from SZ alone– But for now obtain redshifts independently…

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Deep Survey – Optical Fields

• ~ 10 sq. deg. on CFHT

• R = 24.5, z’ = 23.5 (AB)

• WFCAM K = 21.0 (AB)

• Clusters out to z ~ 1.5

• Feedback on SZ selection function

• Red Cluster Sequence (e.g. Gladders & Yee)

• Voronoi tessellation (Culverhouse)

• Full Bayesian analysis (Zwart & Hobson)

• Spectroscopy

0.96

°

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Other Science

• CMB power spectrum at high angular scales (ℓ > 3000, cf VSA)

• Other non-Gaussian features, e.g. cosmic strings, ionization regions

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Summary

• AMI has started obs of known clusters (astro-ph/0509215)

• Shallow blind survey of optical fields begins summer 2006

• Deep survey as soon as LA commissioned

• Open to guest observers