1. Dick Plambeck UC Berkeley (for the CARMA consortium) www.mmarray.org

2. + UChicago SZA 8 3.5-m antennas
Berkeley-Illinois-Maryland Assn. array m diameter antennas
Caltech array m antennas
+ UChicago SZA m antennas

3. people
project manager: Tony Beasley
OVRO
D. Woody
S. Scott
J. Lamb
D. Hawkins
J. Carpenter
A. Sargent
G. Blake
N. Scoville
Berkeley
D. Plambeck
M. Wright
A. Bolatto
C. Kraybill
M. Fleming
L. Blitz
W.J. Welch
Maryland
M. Pound
P. Teuben
K. Rauch
S. Vogel
L. Mundy
A. Harris
Illinois
R. Plante
D. Mehringer
L. Snyder
R. Crutcher
L. Looney
+ programmers, engineers, technicians, postdocs, graduate students

4. antennas 3 different antenna diameters - a heterogeneous array
CARMA
CARMA + SZA
# antennas 15 23
# baselines
105
253
collecting area
773 m2
850 m2
3 different antenna diameters - a heterogeneous array
exploit new algorithms for mosaicing, high fidelity imaging
sensitive to wide range of spatial frequencies; image large objects

5. M33

6. BIMA mosaic of M33
CO GHz
759 pointing centers

7. BIMA mosaic of M33 148 GMCs detected
overlie HI filaments (HI image: Deul & van der Hulst 1987)

8. receiver bands freq (GHz) OVRO BIMA SZA for the 1mm and 3mm bands:
SIS
85-116
SIS (70-116)
MMIC
29-37
HEMT 22
for the 1mm and 3mm bands:
4 GHz bandwidth, 1 polarization at first light
continuum sensitivity: 2-3 mJy/beam, in 1 minute
230 GHz brightness sensitivity: 1 K for 1 km/sec channel, 1'' beam, in 1 hour

9. site selection and acquisition
requirements:
within 60 minute drive of existing OVRO infrastructure
elevation ft for good atmospheric transmission but low snow load
400-m diam flat area, + baselines to 2 km
avoid environmental battles
all such sites are in Inyo National Forest, require Environmental Impact Report

10. environmental studies done for 2 sites
Cedar Flat
Juniper Flat
OVRO

11. Juniper Flat – 7900’

12. Cedar Flat – 7300’

13. Cedar Flat: 20 min drive to OVRO on paved road, maintained (and plowed) by Caltrans
simulated antenna
Highway 168

14. 225 GHz
 Percentiles
25% < 0.12
50% < 0.16
75% < 0.28

15. array configurations 5 antenna configurations, approx 55 pads
2 km max baseline

16. Cedar Flat E-array (most compact) synth beam 4.5" at 230 GHz
Highway 168

17. D-array synth beam 1.8"

18. C-array synth beam 0.8"

19. B-array synth beam 0.32"

20. A-array synth beam 0.13"

21. A-array u,v coverage for declination –30 10-m antennas only (15 baselines)

22. u,v coverage for declination –30 10-m vs 10-m, 6-m vs 6-m antennas only (60 baselines)

23. u,v coverage for declination –30 correlate all antennas (105 baselines)

24. A-array synthesized beam, declination –30 0.26 × 0.14" FWHM
5% contours

25. BIMA detection of 86 GHz radio flare in Orion
20 Jan 2003
beam 0.9 x 0.5''
Bower et al 2003

26. 86 GHz flux increased from 40 mJy to 140 mJy in ~ 4 hrs
20 Jan UT
20 Jan UT

27. most compact array BIMA antennas within collision range
SZA provides even shorter spacings
combine with single dish measurements from 10.4-m antennas

28. antenna transporter avoid ‘custom’ vehicle
50% of weight on tow vehicle for traction

29. transporter tow vehicle: 6-wheel drive military truck (Oshkosh MTVR)

32. Current Concept
antenna transporter

34. fiberoptics
all communication with antennas via 8 singlemode optical fibers
length change with temperature is 1 part in 105 – need round trip phase measurement
based on existing BIMA system

35. diurnal changes in fiber length (BIMA data from July 2002)
fiber lengths
Sun hits fibers
135’ of fiber at outdoor air temp ( = 200 nsec)
 ~ 2 psec/C
 ~ 180°/C at 230 GHz
outdoor air temp

36. BIMA round trip phase measurement
synth
laser
TRX
cpl RX
MXR
phslck ref 
fiber 1
fiber 2
advantage: no electronics at the antenna, just a fiber coupler
disadvantage: lengths of fibers 1 and 2 must track with temperature and flexure (requires loose tube fiber)

37. fiber lengths in each cable track each other within fraction of picosecond
other cables
3 fibers in one cable

38. raw phases on 3c454.3 through sunrise

39. phases on 3c454.3 through sunrise after correction

40. Caltech Cobra correlator
based on FPGAs, not custom correlator chips
4 GHz bandwidth
256 channels, 20 MHz resolution
15 baselines

42. CARMA first light correlator
uses Cobra hardware design
15 telescopes, 105 baselines
8 independent sections:
may be positioned anywhere in 4 GHz IF band
choose 2, 8, 31, 62, 125, 250, or 500 MHz bandwidth
velocity resolution 0.04 to 40 km s-1/ channel at 1.3 mm
separate SZA correlator: antennas, 28 baselines, 8 GHz bandwidth

43. Cobra: each board handles 5 baselines, MHz/baseline, 32 chans/baseline CARMA: reprogram FPGAs to handle baselines, add spectral line capability

44. education and public outreach

45. graduate student training
John Carlstrom
Leslie Looney

46. BIMA summer school

47. public outreach

48. BIMA antenna move
build new antenna bases (compatible with pad design, transporter) at high site
dismantle antennas at Hat Creek, load onto trucks: 2 trucks/antenna
1 convoy = 2 trucks; travel time 4-5 days
entire antenna move approx 8 weeks

49. moving the BIMA antennas: keep dish and feed legs intact

50. OVRO antennas will be dismantled to pass through “the narrows”

51. timeline Jan 2003 draft environmental document submitted Mar 2003
Forest Service decision: Cedar Flat
Jun 2003
end of public comment period
Aug 2003
Forest Service record of decision
Oct 2003
appeals period ends
early 2004
SZA operational at high site
mid 2004
move OVRO and BIMA antennas to high site
2005
begin operation

52. Project Goal Build a new mm array emphasizing New science
Improved continuum/spectral-line sensitivity
Unique: Image on all angular scales: HR, Wide FOV
Operational flexibility
Student training - “hands-on”
New instrumentation & observational techniques
Public outreach

53. outline site antenna configurations antenna transporter correlator
fiberoptic LO distribution
scientific capabilities
timeline