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University of Sydney Facilities. Sydney University Stellar Interferometer (SUSI). Molonglo Radio Telescope (MOST/SKAMP). Used for research in both astronomy/astrophysics and instrumentation. Funded by external competitive grants. Important role in student training. Who’s involved?. - PowerPoint PPT Presentation
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17 Dec 2004 E.M. Sadler 1
University of Sydney Facilities
Sydney University Stellar Interferometer (SUSI)
Molonglo Radio Telescope (MOST/SKAMP)
Used for research in both astronomy/astrophysics and instrumentation. Funded by external competitive grants. Important role in student training.
17 Dec 2004 E.M. Sadler 2
Who’s involved?
SUSI: Peter Tuthill, John Davis, Mike Ireland, Andrew Jacob, Julian North, John O’Byrne, Steve Owens, Gordon Robertson, Bill Tango
MOST/SKAMP: Anne Green, Richard Hunstead, Elaine Sadler, Duncan Campbell-Wilson, Tim Adams, John Barry, Adrian Blake, John Bunton, Julia Bryant; David Crawford, Helen Johnston, Mike Kesteven, Greg Kingston, Martin Leung, Daniel Mitchell, Tom Mauch, Barbara Piestrzynska, Tony Turtle, Sergiy Vinogradov
Plus Australian and overseas collaborators
17 Dec 2004 E.M. Sadler 3
SUSI: A pictorial introduction
17 Dec 2004 E.M. Sadler 4
SUSI Science Programs
New red (500-900 nm) beam-combiner is now fully commissioned and science program underway
Single Stars• Diameters, Effective Temperature scale• Stellar atmosphere studies• Winds, shells, circumstellar matter• Rapid Rotators - Oblateness• Pulsating Stars, Cepheid distance scale
Binary Stars• Double-lined spectroscopic binaries give mass, distance• Ellipsoidal Variables – multiple distortions• Low Mass/Faint companions
17 Dec 2004 E.M. Sadler 5
Delta Canis Majoris at 700 nm
0.0
0.2
0.4
0.6
0.8
1.0
1.2
0 5 10 15 20 25 30 35 40 45 50
Projected Baseline (m)
Correlation
(Preliminary data processing)
Angular Diameter: CMa (F8 Ia)
Angular diameter = 3.471 +/- 0.022 mas
17 Dec 2004 E.M. Sadler 6
Angular Diameter of l Carinae against Phase
2.4
2.5
2.6
2.7
2.8
2.9
3.0
0.0 0.5 1.0 1.5Phase
Angular Diameter (mas)
SUSI 700nm UD Diameters (prelim)Repeated dataDay ticks
1 day intervals
Cepheid l Car: Diameter Variations
17 Dec 2004 E.M. Sadler 7
Molonglo Observatory Synthesis Telescope
Array of 600 cylinders, each 111 x 15 m (area 1650 m2)
Prototype: SKAMP (10,000 m2) operating to 1 GHz by 2007
1.6km cylindrical reflector, currently operating at 843 MHz. Largest radio telescope in the southern hemisphere.
17 Dec 2004 E.M. Sadler 8
Wide-field images of the radio sky
‘Radio Schmidt’ telescope: 2.7o field of view, excellent surface-brightness sensitivity
17 Dec 2004 E.M. Sadler 9
Sydney University Molonglo Sky Survey (SUMSS)
www.astrop.physics.usyd.edu.au/SUMSS
SUMSS: Imaging survey of the entire southern sky, at similar sensitivity and resolution to the northern NVSS. Now 95% complete: FITS images and catalogue released on the web.Key science:• Local radio source populations to z~0.3• Angular clustering at z~1• Radio galaxies at z>3
17 Dec 2004 E.M. Sadler 10
SUMSS and optical redshift surveys
Overlap with 2dF/6dF gives spectra of 10,000+ radio AGN and starburst galaxies.
Local radio luminosity functions and timescales; local benchmark for high-z studies.
6dFGS spectra
17 Dec 2004 E.M. Sadler 11
Clustering studies with SUMSS
Angular (two-point) correlation function: w() = A
(Blake et al. 2004)
3-D clustering studies now in progress using SUMSS/NVSS/6dFGS (Mauch & Rawlings 2005 )
17 Dec 2004 E.M. Sadler 12
SKA Molonglo Prototype (SKAMP)
Goal: To equip the Molonglo telescope with new feeds, low-noise amplifiers, digital filterbank and FX correlator with the joint aims of:
(i) developing and testing SKA-relevant technologies and
(ii) providing a powerful new facility for low-frequency radio astronomy in Australia
A$1.9 million funding from 2001 MNRF grant, ARC Linkage program and University of Sydney: timescale 2002-2007, PI Anne Green
International technology demonstrator for the cylindrical reflector SKA concept (one of six SKA designs currently being evaluated)
17 Dec 2004 E.M. Sadler 13
From MOST to SKAMP:A three-stage approach
I. 2004-5: Narrowband continuum correlator (843 MHz, 4 MHz bandwidth, 88+2 stations = 4,000 baselines) [In parallel with SUMSS]
II. 2005-6: Increase bandwidth and add spectral capability (830-860 MHz, 4,000 baselines, 2,000 frequency channels) [Uses existing linefeed]
III. 2006-7: New linefeed + enhanced correlator (300-1420 MHz, >50 MHz bandwidth, 4,000 baselines, 2,000 frequency channels) [New wide-band linefeed for ~10% of collecting area is funded under MNRF; additional ~$1 million would equip full 18,000 m2 collecting area with new line feeds and new mesh]
17 Dec 2004 E.M. Sadler 14
Stage I correlator: high-dynamic range continuum imaging
2004: Stage I correlator will allow use of self-calibration methods on MOST
Current MOST imaging dynamic range is 100-200:1 (similar to intrinsic dynamic range of VLA)
Use of self-calibration on VLA enabled imaging dynamic ranges of 105-106:1
Current imaging dynamic range of MOST limits imaging of faint sources (eg young supernova remnants) near
bright sources (eg Galactic Centre)
(MGPS Green et. al.)
17 Dec 2004 E.M. Sadler 15
Stage II: FX correlator, spectral-line capability
2005-2006: 2,000 spectral channel FX correlator operating at 830-860 MHz enables, eg:• Measurements of HI absorption at z = 0.7 to 0.8 that capitalise on the large collecting area of MOST• OH megamaser emission surveys at z~1• Observing recombination lines of C and H, which set constraints on physical conditions in the ISM (Anantharamaiah & Kantharia 1999)
Stage II enables absorption-line measurements at z = 0.7 to 0.8, where
existing methods work poorly
(Lane 2000)
(Lane and Briggs 2001)
17 Dec 2004 E.M. Sadler 16
Stage III Target Specifications
Parameter 1420 MHz 300 MHz
Frequency Coverage 300–1420 MHz
Instantaneous Bandwidth >50 MHz
Resolution ( < -30°) 26" x 26" csc|| 123" x 123" csc||
Imaging field of view 1.5° x 1.5° csc|| 7.7° x 7.7° csc||
uv coverage Fully sampled
Tsys < 50K < 150K
System noise (1) 12hr8 min
11 Jy/beam100 Jy/beam
33 Jy/beam 300 Jy/beam
Polarisation Dual Linear
Correlator Full Stokes
Frequency resolution 120–1 kHz (FXF mode down to 1 Hz)
17 Dec 2004 E.M. Sadler 17
SKAMP III science example: HI emission from distant galaxies
8
9
10
11
0 0.05 0.1 0.15 0.2 0.25 0.3
Redshift z
HIPASS (500s)
SKAMP III (10x12 h)
(12 h)
log 10
Mli
m (
HI)
(M
sun)
Typical bright spiral
HI in the nearby Circinus galaxy (Jones et al. 1999)
SKAMP should reach HI mass limits typical of bright spiral galaxies at z=0.2 (lookback time ~3 Gyr), allowing a direct measurement of evolution in the HI mass function.
17 Dec 2004 E.M. Sadler 18
Summary
SUSI: Now fully-operational. Unique capabilities as a visible-light interferometer, and science program likely to continue for at least five years. Could also be used as a technology testbed for Antarctic interferometers.
Molonglo: SUMSS survey 95% complete; new science program from 2006 using spectral-line capability.
SKAMP: Vital pathfinder to aspects of SKA technology [cylindrical antennas; software beam-forming; high dynamic-range imaging with fully-sampled uv plane], and hence an important partner to other efforts such as NTD. Modest additional funding (~$1 million) could provide a powerful science instrument with complementary strengths to xNTD.
17 Dec 2004 E.M. Sadler 19
Binary star system: Cen
-30
-25
-20
-15
-10
-5
0
5
10
-15 -10 -5 0 5 10 15 20 25 30
y (mas)
x (mas)
1995 MAPPIT Observation
1997 SUSI Observations
1998 SUSI Observations
1999 SUSI Observations
2000 SUSI Observations
Fitted Orbit
E
N
Period: 357.0±0.3 daysInclination: 67.5±0.4 degSemi-major axis: 25.3±0.2 mas