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The JCMT in the ALMA Era

The JCMT in the ALMA Era. Surveying the Sub-millimetre Sky (Canada / Netherlands / Great Britain). Doug Johnstone NRC/HIA. A New Suite of Instruments. Faster bolometer array (SCUBA2) Continuum mapping at multiple wavelengths Ancillary devices (polarimeter, FTS)

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The JCMT in the ALMA Era

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  1. The JCMT in the ALMA Era Surveying the Sub-millimetre Sky (Canada / Netherlands / Great Britain) Doug Johnstone NRC/HIA

  2. A New Suite of Instruments • Faster bolometer array (SCUBA2) • Continuum mapping at multiple wavelengths • Ancillary devices (polarimeter, FTS) • Magnetic fields, line- and SED-fitting • Heterodyne Receiver Array (HARP-B) • 16 receivers @350 GHz (CO 3-2 etc) • Submillimetre array (eSMA)

  3. SCUBA2The Future of Sub-Millimetre Mapping • >100 times faster than present instruments • Survey large regions of the sky quickly • Square degrees per hour • Survey to the point-source confusion limit • Allow for ‘complete’ source counts • Finding chart for ALMA • Beam size 15", centroid to a few arcseconds

  4. Focal plane layout ~8 arcmin (~100mm) SCUBA2 Key Features • A large 7x7 arcminute field-of-view • Fully sampled - Nyquist at 850m • Sensitivity governed by the sky background • Simultaneous imaging at 850m & 450m • No chopping required • Greater sensitivity to large-scale structure

  5. Estimated performance m m 450 m 850 m Parameter SCUBA SCUBA-2 SCUBA SCUBA-2 Per-pixel NEFD 400 75 90 32 Ö (mJy/ Hz) Point-source NEFD 400 107 90 22 Ö (mJy/ Hz) Point source flux 1 10 1 12 Extraction speed Large area mapping 1 810 1 980 speed

  6. JCMT/SCUBA-2 (450m) 7 arcsec resolution : 64 arcmin2 field-of-view (simulation by Governato et al.) Herschel/SPIRE (350m) 25 arcsec : 16 arcmin2 (simulation by Hughes & Gaztanaga) JCMT/SCUBA (850m) 14 arcsec : 5 arcmin2 (HDF image from Hughes et al. 1998) Compact ALMA (450m) 0.01 arcsec : 0.02 arcmin2 Large-scale surveys SCUBA-2 will map large areas of sky at least 10 times faster than ALMA to the same S/N...

  7. Deep extragalactic surveys A 50-hr observation with SCUBA Deep imaging? It would take SCUBA-2 ~50 hours to map 1 deg2 area of sky to the confusion limit (0.5 mJy) at 850m

  8. Wide-field Galactic surveys SCUBA Galactic Centre Survey ~15 shifts (or 120 hrs) of telescope time Galactic Plane SCUBA-2 could map the entire area shown left in just a couple of hours to the same S/N... Full moon All sky survey? It would take SCUBA-2 ~500 hours to map the entire Mauna Kea sky to the depth of the SCUBA Galactic Centre image

  9. Ophiuchus – JCMT 2003 In 2003 observed 4 sq. degrees to 40 mJy/bm as part of the COMPLETE Project. Took 40 hours! Largest SCUBA map to date Expect 100’s of new compact sources Found only 2!

  10. Ancillary Instruments • Polarimeter • Measure polarized emission and orientation • Importance of magnetic fields (especially in regions of star formation) • Study the properties of dust • Fourier Transform Spectrometer • Moderate-resolution spectrum • Quickly obtain strong emission lines (e.g. CO) • Hot core diagnostics • Low-resolution spectrum • SED shape - temperature and dust emissivity

  11. Polarimetry of the Orion Ridge

  12. When and How? • SCUBA2 on the telescope by end of 2005 • Full functionality in 2006 • Legacy Surveys being determined NOW! • Likely 50% of telescope time • Still time to forward ideas to JCMT members • Tri-Partate agreement for JCMT expires 2009 • Future of the JCMT beyond 2009 open to ideas • There will still be a great deal of sky to map! • Partenership Opportunities

  13. Canadian SCUBA-2 Consortium SCUBA-2 Website: http://www.roe.ac.uk/ukatc/projects/scubatwo

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