lba calibrator survey
DESCRIPTION
LBA Calibrator Survey. Chris Phillips eVLBI Project Scientist 23 July 2009. The LBA. ASKAP. ATCA. Mopra. Ceduna. Perth. Parkes. Sydney. Tidbinbilla. Melbourne. Hobart. The LBA. 6 telescopes within Australia Parkes, 64m ATCA, 5x22m phased array Mopra, 22m Hobart, 26m - PowerPoint PPT PresentationTRANSCRIPT
LBA Calibrator Survey
Chris Phillips
eVLBI Project Scientist
23 July 2009
ATCA
Hobart
Sydney
Ceduna
ASKAP
The LBA
Perth
Melbourne
Tidbinbilla
Mopra
Parkes
The LBA
• 6 telescopes within Australia• Parkes, 64m• ATCA, 5x22m phased array• Mopra, 22m• Hobart, 26m• Ceduna, 30m• Tidbinbilla, 34m&70m
• Also • Hart, Kokee, TIGO, O’Higgins, Shanghai, Kashima
• 1-20 GHz • Data rates up to 1 Gbps
• LBADR recording system (Mark5b mode)• eVLBI up to 1 Gbps
• Pa, At, Mp, Ho (64-128 Mbps)
CSIRO. eVLBI-Aus
LBA Operations
• Coordinated VLBI for 3 weeks/year• 3-4 dedicated sessions/year
• Fixed schedule• Actual schedule depends on experiment request
and TAC grading
• Correlated using DiFX• Correlation contracted to Curtin University
(Steve Tingay, Cormac Reynolds, Hayley Bignall)
CSIRO. eVLBI-Aus
LBA - Future
• Wide band DAS• 1-2 GHz• ATCA CABB commissioned• DFB3 Pulsar Backend for Parkes/ATCA
• AuScope• 3x12m for geodesy• WA, NT and Tasmania• S/X only• No operational funds for astronomy
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ASKAP
• Number of dishes 36 • Dish diameter 12m• Max baseline 6km• Resolution 30 • Sensitivity 65 m2/K
• Observing frequency 700 – 1800 MHz• Field of View 30 deg2
• Processed Bandwidth 300 MHz
• Multiple VLBI beams• Up to 30, requested at least 2
• Combined with cluster-cluster VLBI at other stations
• Parkes multibeam, ATCA array, Hobart 12mCSIRO. eVLBI-Aus
LBA Astrometry
• Adam Deller’s PhD Thesis• Parallaxes to 7 pulsars
• J0437-4715: Most accurate pulsar distance to date
• 1E 1547.0–5408 magnetar propermotion• 6.7 GHz methanol maser parallax
• H20 maser proper motion in LMC
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LBA Astrometry – The Problem
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AT20G
• All Southern sky 20 GHz survey• South of Dec 0
• 8 GHz bandwidth• Analog correlator
• 3 antenna• Sensitivity limit ~50 mJy
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Survey Design
• Wideband (8 GHz) analogue correlator
• Fast scan rate: 15°/min at meridian
• Follow-ups at 4.8, 8.6 & 20 GHz to confirm detection and for spectral info
Survey Parameters
SurveyFrequency
(GHz)Source
#Area
(sq. Deg.)Slim(mJy)
Taylor et al. 2001 15 66 60 20
9C (Waldram et al. 2003 - 2007)
15 (22, 43) 465 520 25
WMAP (Wright et al. 2008) 23, 33, 41, 61, 94
390 Full Sky (40000)
1000
AT20G 20 (4.8,8.6) 5800 ½ Sky (20000) 50
LBA Calibrator Survey
• Using AT20G as a basis for sample to increase density of Southern calibrators
• σ > -0.55• S(8.4 GHz) > 190 mJy• Dec < -40
• Correlated at Bonn• Native Mark5A, Mark5B, translated Mark5b
shipped electronically• Processed with CALC/Solve by Leonid Petrov
• 8 GHz only – limited by LBA DAS• 4x 24hr observed
• 3x 24hr correlated/analyzed
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LBA Calibrator Survey - Results
• 422 new sources observed• 326 processed• 317 detections
• 97.2% detection rate
• 4 more epochs proposed
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Results
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BeforeNowFinal
Results
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Probability of Close Calibrator
Zone [-90, -40] [+40, +90]
Jan 2008 Now 2010 Now
2deg radius 21.2% 57.8% 78.0% 73.4%
3deg radius 41.2% 84.4% 96.2% 95.0%
4deg radius 60.5% 96.0% 99.5% 99.6%
# objects 163 517 1000 721
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Results – Formal Errors
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Compactness
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Contact UsPhone: 1300 363 400 or +61 3 9545 2176
Email: [email protected] Web: www.csiro.au
Thank you
ATNFChris PhillipseVLBI Project Scientist
Phone: +61 2 93724608Email: [email protected]: www.atnf.csiro.au/vlbi