The SIRTF SWIRE Survey SWIRE is a shallow/moderate depth survey of ~70 sq. degrees in all 7 SIRTF imaging bands

5 sensitivities:

17.5 mJy160 m

2.75 mJy70 m

0.45 mJy24 m

32.5 Jy8.0 m

27.5 Jy5.8 m

9.7 Jy4.5 m

7.3 Jy3.6 m SIRTF is ideally designed for detailed study of the history of star formation

MIPS is optimized for star-forming galaxies and AGN

IRAC is optimized for old and/or reddened stellar populations

SWIRE Science Goals

To enable fundamental studies of cosmology and galaxy evolution in the Mid- and Far-IR for 0.5<z<2.5:

• Evolution of star-forming and passively evolving galaxies with time in the context of structure formation models

• Spatial distribution and clustering of evolved galaxies, starbursts and AGN, and the evolution of their clustering

• Evolutionary relationship between galaxies and AGN, and the contribution of AGN accretion energy to the cosmic backgrounds

SWIRE Survey Design

• The 1<z<2.5 universe is less well studied than the z>3 universe

• Galaxy evolution must be studied in the context of environment

SWIRE will sample:

– Several hundred >100 Mpc co-moving volumes

– Redshift range 0.5<z<2.5

– 7 target fields to combat cosmic variance

The SIRTF SWIRE Survey

Plotting only every 10th galaxy

SFRs for galaxies; compared to integrated SFH (which is normalized by volume)

SWIRE

Lockman Hole (preliminary pointing)

Simulated Image; Shupe, Fang & Xu

The Power of the Mid-IR

As the 7.7m PAH feature redshifts into the 24m filter

feature in the predicted f24m< 2mJy counts.

Gordon et al.

IRAC Observation Plan

For a 10 sq deg area, need 24 AORs for two coverages

• Each AOR: 1.75º x 30

6 columns by 21 rows, grid spacing 300

two cycling dithers at each map grid point

• Total coverage: 4x30 sec per point

MIPS Observation Plan

• Optimization at 24 and 70m due to confusion limit at 160m.

• Medium scan rate: 4 second exposures

– 10x redundancy at 24 and 70 microns

– filled 160 m map

• Two epochs

– redundancy

– asteroid/transient removal; destriping

The Importance of Field Selection:

Schlegel et al. 1998 DIRBE-calibrated IRAS 100m map

B100 Contours at 1 and 2 MJy/sr

||=45 contours

Cirrus/NH/extinction must be minimized

Seb Oliver

SWIRE Field Selection

FIELD RA

J2000

Dec ISSA

MJy/sr

E(B-V) Size

Sq. deg

ELAIS-S1 00h38m30s -44d00m00s <0.4 0.008 15

XMM-LSS 02h21m00s 05d00m00s 1.1 0.027 10

Chandra-S 03h32m00s -28d16m00s  <0.4 0.001 5

Lockman Hole 10h45m00s +58d00m00s <0.4 0.006 15

Lonsdale Hole 14h38m00s   +59d15m00s <0.4 0.012 10

ELAIS-N1 16h13m30s   +55d16m00s <0.4 0.007 10

ELAIS-N2 16h36m48s   +41d01m45s <0.4 0.007 5

Sensitivity, Cirrus and Confusion Noise

Table A-2: Expected SWIRE Performance: Noise and Sensitivity Wavelength Cirrus noise, 1 #

(1 Mjy/sr at 100 m) Extragalactic* Confusion noise, 1

SWIRE photometric sensitivity, 1

3.6 m 18 nJy 35 nJy 1.4 Jy 4.5m 40 nJy 33 nJy 1.9 Jy 5.8 m 60 nJy 31 nJy 5.5 Jy 8.0 m 300 nJy 43 nJy 6.5 Jy 24m 2.0 Jy 4.8 Jy 0.09 mJy 70m 0.1 mJy 1.3 mJy 0.55 mJy 160m 2.0 mJy 19 mJy 3.5 mJy

Bold: dominant noise term # model of Gautier * derived from Xu et al. model confusion distribution

Supporting Observations

Optical, NIR: NOAO, ESO, Palomar, INT, 2dF, Keck

Three Tiers:

r' 25 70 sq deg

g'r'i'Ks 26 / 25 / 24 / 19.5 12+

g'r'i' 27 / 26 / 25 3+

Supporting Observations

Radio: Median predicted flux is 43Jy

Too deep for large area coverage

Selected very deep VLA in small areas:

• 3 @ 3Jy rms

• 3@ 7.5Jy rms

X-ray: Selection wrt existing/planned deep Xray surveys:

Lockman Hole

Chandra-S

ELAIS

XMM-LSS

Anticipated Early SWIRE Results

BRK magnitude distributions

observations: Cohen et al. 2000, Hogg et al. 2000

ISO 15m sample of Aussel et al. (1999).

Photometric Redshifts

Examples of Additional Science made possible

• Hundreds of field brown dwarfs, especially T (“methane”) dwarfs

• 50-60 circumstellar debris disks (to 100 pc), and HR4796A analogs to 1kpc

•Thermal emission at 8 and 24m from main belt asteroids as small as 1km

• Serendipitous discoveries; rare objects to 1-in-104 to 1-in-106

Identifying SIRTF Sources

Confusion and cirrus noise dominate FIR/submm observations

Good complement comes from deep radio surveys to locate the UV-O-NIR counterparts

– median SWIRE 20cm depth is ~ 75 Jy

– impossible for VLA over large areas

– the Square Kilometer Array can map:

1 sq deg

10 nJy rms, 24 hours or 1 Jy rms, 2 minutes

10-30 mas beam

large scale structures

14Gyr – galaxy evolution – 2 GyrAGN

starburstsmergers

SWIRE:

– 105-106 galaxies

– 104-105 AGN

– hundreds of 100 Mpc-scale cells

swireKauffmann et al