FLS: Extragalactic Component Requirements

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The extragalactic component of the FLS was designed to meet these requirements:

A 5 square degree imaging survey with IRAC and MIPS to a shallow depth of about one minute per pixel on the sky.
- A total of 4 square degrees within the Spitzer Continuous Viewing Zone (CVZ), in an area where IR cirrus is low: 17h10m+61d, where I(100um) = 1-2 MJy/sr
- A separate 1 square degree region whose location will depend on the sky visibility at the end of In-Orbit Checkout (IOC):
  1. in near-CVZ area of low cirrus at 16h20m+54d30m, where I(100um) = 0.4 MJy/sr, or
  2. within the CVZ, if area in (a) is not accessible at the conclusion of IOC.
- MIPS Shallow Survey: 5 passes at fast speed, incorporating three bands
  - Total T(int) = 75 sec per point (24 and 70 um), 15 sec (160 um)
  - Depth reached is 1.3 mJy at 24 um; confusion-limited at 160 um
  - Scan rate = 1 sq.deg. per 3 hours, plus 30% overheads
  - Following estimates for a 5 square degree, 20-hour survey
    
    wavelength
    (µm) Flux Limit
    (mJy, 5-sigma) Gain over
    Past Source
    Counts
    
    24 1.3 ~ 100 ~ 400
    
    70 4.5 ~ 50 ~ 1500
    
    160 27.0 ~ 8* ~ 2500
    
    * ISO covered a few square degrees
- IRAC Shallow Survey: 4 bands simultaneously
  - Total T(int) = 5x12 sec per point
  - Requires ~ 5 hours per sq.deg., including overheads
  - Following estimates for a 5 square degree, 20-hour survey
    
    wavelength
    (µm) Flux Limit
    (mJy, 5-sigma) Gain over
    Past Source
    Counts mean z for L* elliptical
    
    3.6/4.5 0.04 >> 1 stars + ? ~ 1
    
    5.8 0.04 ~ 1* stars + ? ~ 0.4
    
    8.0 0.06 ~ 1* ~ 1500 ~ 0.3
    
    * ISO covered a few square arcminutes
Within the above area, a MIPS/IRAC verification survey of 0.25 square degree or less, with ten times the integration time.
- Should fit within ~30% of time dedicated to shallow survey
Incorporation of ancillary data recommended, primarily for identification purposes.
- Deep R-band or I-band survey, to R(5-sigma) ~ 25.5 mag
- Near-infrared K-band survey to K ~ 18 mag
- Radio survey at 1.4 GHz to 5-sigma sensitivity of ~ 90 micro-Janskys
Conservative experimental design, emphasizing reliability at the expense of sensitivity.