Jim Geach on behalf of the S2CLS consortium The SCUBA-2 Cosmology Legacy Survey.
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Transcript of Jim Geach on behalf of the S2CLS consortium The SCUBA-2 Cosmology Legacy Survey.
What is the SCUBA-2 Cosmology Legacy Survey?Largest of the JCMT Legacy Surveys: 65% of all SCUBA-2 time to be spent on JLS, over half this is spent on CLS
CLS (high redshift) 1778 hours 50.9%
GBS (local star formation) 412 hours 11.8%
SASSy (‘all/ambitious’ sky survey) 480 hours 13.8%
NGLS (nearby galaxies) 100 hours 2.9%
JPS (Galactic plane) 450 hours 12.9%
SONS (stars) 270 hours 7.7%
3490 hours 291 nights
What is the SCUBA-2 Cosmology Legacy Survey?
Simple two tier strategy covering well-known fields:
• Wide survey at 850um in grade 2-3 conditions • Target area 10 deg2 (probably get 50% of this)• Uniform coverage to 1sigma=1.2mJy. • PONG mapping. ~80% complete
• Deep survey at 450um + 850um in grade 1 conditions• Target area 0.25 deg2 • Uniform coverage 1sigma=1.2mJy @ 450um,
confusion limited at 850um. • DAISY mapping. ~50% complete
Science drivers• Comprehensive survey of SMGs detected at 850um
(N~104) over several ~degree scale fields
‣ measure clustering / halo properties‣ constrain bright-end counts‣ reliably probe properties of fainter SMGs (3-5mJy)‣ AGN/starburst connection, transition objects‣ ‘very’ high-z science (IR luminosity density at z>5, rare
objects)‣ cross-correlation studies
• ‘Keyhole’ confusion limited survey at 450+850um
‣ properties of 450um-selected SMGs below HSO confusion limit‣ resolving CIB at 450um (closer to peak)‣ probing very faint end of counts (P(D) analyses)‣ joint stellar/dust/gas morphologies (CANDELS overlap, ALMA)
Targets
‣ COSMOS (2 deg)‣ UKIDSS-UDS/SXDF (1 deg)‣ GOODS-N‣ Extended Groth Strip / AEGIS
‣ Akari-NEP‣ Lockman Hole Owen‣ SSA22
Including deep CANDELS
Other wide fields
S2CLS is a ‘factory’ for detecting dusty starbursts at z>1
Excellent ancillary data (e.g. CANDELS) probing stellar emission, redshifts, morphologies
ALMA offers HST-matched resolution: directly compare dust and gas to stellar emission on sub-galactic scales
Pinpoint counterparts with ~few asec accuracy
ULIRG
LIRG
JEG+Papadopoulos 12
Negative k-correction at 850um provides uniform luminosity selection at fixed flux limit out to z~10! Huge volume column.
At z>2, bulk of IR luminosity density is emitted by ULIRGs: epoch of formation of most massive galaxies today
Why are we doing this?Observed 850um flux density
Bethermin+11
First measurement of 450um number counts
JEG+ 2013
Directly resolve ~15% of CIB @ 450um
Recover ~50% with MIPS stack
Herschel
SCUBA-2
JEG+ 2013
Average sub-mm flux of Lyman Break GalaxiesCoppin, JEG+ 2014 arXiv:1407.6712
Stacked LBGs in SXDF at z=3, 4, 5 (850um)
Typical S850 ~ 0.2 - 1 mJy
Next steps…
Clear need to complete COSMOS field – tremendous legacy value in this field (including HSC UD). Would require at least another winter (probably two) to reach full CLS depth.
Complete the deep 450+850 mapping of CANDELS fields – progress has been severely hampered by poor weather. Complement to HSC UD.
Obvious continuation of CLS would be wider area –mapping of all HSC deep fields to ~30 deg2? Time investment would be ~1000s hours for useful depths.