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7. FUTURE DEVELOPMENTS IN SUBMM COSMOLOGY

During the last 4 years, the first steps have been taken towards investigating the Universe using direct submm-wave surveys. The technologies of the class of detectors that made these initial surveys possible are still developing rapidly. Many instrumentation projects are underway, which will allow us to increase the sizes of samples of distant submm galaxies, and to study known examples in more detail; some of their key features are outlined in Tables 1-3.

Table 1. Wavelengths lambda, sensitivities (as noise equivalent flux density-NEFD), fields of view (FOV), and confusion limits due to galaxies and the ISM (in brackets) for existing and future ground-based and airborne instruments.


Name lambda NEFD FOV Confusion
(µm) (mJy / (Hz)1/2) (arcmin2) (mJy)

SCUBA 850 80 1.7 0.12 (9 × 10-4)
450 160 1.7 0.053 (3 × 10-3)
MAMBO1,2 1250 95 1.0 0.05 (7× 10-5)
SCUBA-II 850 28 64 0.12 (9 × 10-4)
450 90 64 0.053 (3 × 10-3)
HAWC-SOFIA 200 408 9.0 1.2 (0.30)
BOLOCAM-CSO 1100 42 44 0.32 (2 × 10-3)
BOLOCAM-LMT 1100 2.8 2.5 6 × 10-3 (4 × 10-5)
BLAST 750 115 appeq 10 3.9 (0.25)
450 130 appeq 10 6.8 (0.7)
300 150 appeq 10 7.8 (1.1)
SMA 850 170 0.2 < 10-7 ( < 10-6)
450 1700 0.05 < 10-8 ( < 10-4)
ALMA 870 1.9 0.050 < 10-7 ( < 10-6)
450 11 0.013 < 10-8 ( < 10-4)
Extended VLA 20.5 cm 0.40 700 ~ 0 (~ 0)
SKA 20.5 cm ~ 10-2 TBD ~ 0 (~ 0)

An estimate of the speed of a survey down to a chosen depth can be obtained by multiplying the FOV by the the square of the NEFD value. The approximate extragalactic confusion noise values are the flux density at which there is one brighter source per beam (Blain et al., 1998; Fig. 13). This corresponds approximately to the width of peak in the non-Gaussian confusion noise distribution (see Fig. 12). The expected ISM confusion noise (in brackets) is calculated for a 100-µm surface brightness B0=1 MJy sr-1 (Helou and Beichman, 1990), and scales as B01.5. Other instruments under development, which have not published detailed performance estimates include the 350-µm SHARC-II camera for the CSO. The FOV and NEFD values are chosen to provide the correct results for making a fully-sampled image of the sky, not measuring the flux from a single galaxy. Updated from Table 1 in Blain (1999b). Relevant references are listed in Table 3. TBD: to be decided.
1 Note that the FOV of MAMBO is expanded by a factor of 3 for the winter of 2001/2002, with a 117-bolometer detector array.
2 A similar device SIMBA is being commissioned at SEST.

Table 2. The equivalent to Table 1 for space-borne instrumentation.

Name lambda NEFD FOV Confusion
(µm) (mJy / [(Hz)1/2]) (arcmin2) (mJy)

Herschel-SPIRE 500 114 40 2.9 (0.16)
350 90 40 2.6 (0.12)
250 84 40 1.6 (0.24)
Herschel-PACS 170 24 6.1 0.80 (0.16)
90 24 6.1 0.03 (0.01)
SIRTF-MIPS 160 18 2.5 6.6 (3.1)
70 4.5 25 0.28 (0.07)
24 1.8 25 6 × 10-4 (2 × 10-4)
SIRTF-IRAC 8.0 0.15 26 8 × 10-2 (~ 10-6)
Planck Surveyor 350 26 All-sky 50 (70)
550 19 All-sky 22 (12)
850 16 All-sky 8.1 (1.6)
SPECS testbed 250 0.17 4 ~ 10-5 (~ 10-3)
SPIRIT

Note that the values listed for Planck Surveyor apply to an all-sky survey. Another instrument under development, which has not published detailed performance estimates is the 50-200-µm sky survey from the Japanese ASTRO-F/IRIS satellite sky survey.

Table 3. References to instruments listed in Tables 1 and 2.

Name Information

SCUBA Holland et al. (1999)
MAMBO Kreysa et al. (1998)
SCUBA-II www.jach.hawaii.edu/JACpublic/JCMT/Continuum_ observing/SCUBA-2/home.html
SOFIA Davidson et al. (1999); sofia.arc.nasa.gov
BOLOCAM Glenn et al. (1998); www-lmt.phast.umass.edu/ins/continuum/bolocam.html
BLAST Devlin (2001); http://chile1.physics.upenn.edu/blastpublic/
SMA Ho (2000); http://sma-www.harvard.edu/
ALMA Wootten (2001); www.alma.nrao.edu
SKA www.astron.nl/p/skaframe.htm
Herschel-SPIRE www.ssd.rl.ac.uk/spire
Herschel-PACS pacs.ster.kuleuven.ac.be
SIRTF-MIPS & IRAC sirtf.caltech.edu
Planck Surveyor astro.estec.esa.nl/Planck
SPECS / SPIRIT Mather et al. (1998); space.gsfc.nasa.gov/astro/specs

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