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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):
- in near-CVZ area of low cirrus at 16h20m+54d30m, where I(100um) =
0.4 MJy/sr, or
- 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.
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