Australia Telescope 20 GHz survey (AT20G):Australia Telescope 20 GHz survey (AT20G):An UpdateAn Update

Ron Ekers (ATNF, PI),Sarah Burke(Haverford-Swinburne), Mark Calabretta (ATNF), Gianfranco De Zotti (Padua), Paul Hancock (U Sydney), Carole Jackson (ATNF), Michael Kesteven (ATNF), Marcella Massardi (SISSA-ATNF),

Tara Murphy (U Sydney), Katherine Newton-McGee (U Sydney), Chris Phillips (ATNF), Roberto Ricci (ATNF), Elaine Sadler (U Sydney), Lister Staveley-Smith (ATNF), Mark Walker (MAW Tech), Jasper Wall (UBC),

Warwick Wilson (ATNF)

http://www.atnf.csiro.au/research/AT20G - VSOP-2 09 Mar 2007

• CMB MissionsCMB Missions

• Calibrator manuals for radiotelescopesCalibrator manuals for radiotelescopes

ALMAALMA

ATCAATCA

SKASKA

• Radio Source population studiesRadio Source population studies

WMAP & PLANCKWMAP & PLANCK

MotivationsMotivations

100121612618 GHzRicci et al. 2004

AT20G

22.8 GHz

15 (33) GHz

15 GHz

Freq.

4015,288 38% sky4406AT20G

1000All sky 323Hinshaw et al. 2006 (WMAP3)

25520465Waldram et al. 2003 (9C)

20 6066Taylor et al.2001

Slim (mJy)Area (sq. deg.)Source no.Project

Existing Surveys at high frequencyExisting Surveys at high frequency

WBCORR WBCORR

Wide Band analogue correlatorWide Band analogue correlatorFrequency range 16-24 GHzBandwidth 8GHz (8 frequency channels)

All sky in 10(15)degree declination regionsAll sky in 10(15)degree declination regions includes galactic plane

No delay correction possibleNo delay correction possiblescan along the meridian

High scan rateHigh scan rate: 15 deg./min

Sky Coverage

Missing DataMissing Data

Combine the scans to make maps

Candidate Candidate SourcesSources

The SurveyThe Survey

Blind scan Calibration Map making Selection criteria LIST OFLIST OF

CANDIDATESCANDIDATES

Follow up Follow up @ 20GHz@ 20GHz

Observation of the candidates LIST OF SOURCESLIST OF SOURCES

Follow up @ Follow up @ 4.8 and 8.6 GHz4.8 and 8.6 GHz

low frequency observations of the confirmed sources

DATA ON EACH SOURCEDATA ON EACH SOURCE

PIPELINE PIPELINE of data analysisof data analysis

flagging calibration data reduction polarization analyses imaging

AT20G CATALOGUEAT20G CATALOGUE

Equal area sky maps of the AT20G follow-up sources (2004-2006)

4406 extragalactic sources detected in 15288 sq. deg.

Polar projection Aitoff projection

AT20G source counts

Integral source countsIntegral source countsNormalized differential countsNormalized differential counts

Spectral index from AT20G 2004-2006

3737 extragalactic sources3737 extragalactic sources 280 extragalactic sources 280 extragalactic sources

All AT20G sampleAll AT20G sample Bright Sample (SBright Sample (S20 20 > 0.5 Jy)> 0.5 Jy)

11%

53%

13%

22%

8% 20%

29% 43%

Massardi et al. 2007 in prep.Massardi et al. 2007 in prep.

AT20G Polarization Properties

5GHz 8GHz 18GHz

Mean 2.43% 2.63% 2.83%

Median 2.19% 2.18% 2.10%

Max 8.02% 9.38% 10.66%

• S20>500mJy; < -30º

• ~200 sources observed

5GHz5GHz 8GHz8GHz 18GHz18GHz

Burke et al. 2007 in preparationBurke et al. 2007 in preparation

Gravitational lens search

Spectral index (4.8-8.6 GHz)Spectral index (4.8-8.6 GHz)

-0.5-0.5 00

11

0.50.5

Am

p(6)

/Am

p(no

6)A

mp(

6)/A

mp(

no6)

0619-20540619-2054

1755-21441755-2144

PKS1830-211PKS1830-211

0711-19510711-1951

Plot courtesy of R.ChhetriPlot courtesy of R.Chhetri

•Clean-up follow-ups Clean-up follow-ups (C1049: -90°<dec< -15(C1049: -90°<dec< -15ºº))

•Follow-up of galactic objects Follow-up of galactic objects (UCHII: Murphy et al. 2007 in prep.)(UCHII: Murphy et al. 2007 in prep.)

•3mm follow-up 3mm follow-up (C1392: Sadler et al. 2007 in prep.)(C1392: Sadler et al. 2007 in prep.)

•Variability studies Variability studies (2002-2004: Sadler et al. 2006)(2002-2004: Sadler et al. 2006)

•Polarization studies Polarization studies (C1633: Burke et al. 2007 in prep.)(C1633: Burke et al. 2007 in prep.)

•Upcoming data release Upcoming data release (BSS: Massardi et al. 2007 in prep.)(BSS: Massardi et al. 2007 in prep.)

• Search for grav. lensesSearch for grav. lenses (CLASS in the South: Chhetri et al.)(CLASS in the South: Chhetri et al.)

• ......

The Future of AT20GThe Future of AT20G