Wide Field Astronomy from Space

Steven Beckwith

Space Telescope Science Institute

January 9, 2002

1/9/2002 2

Limits:

Space advantages:Space advantages: Low BLow B Small Small over FOV over FOV PSF stabilityPSF stability Photometric stabilityPhotometric stability Full sky coverageFull sky coverage 24 hr operation24 hr operation

Ground advantagesGround advantages Large area telescopesLarge area telescopes Upgradable detectors Upgradable detectors

(increase/repair FOV)(increase/repair FOV) High survey speed at BLIPHigh survey speed at BLIP

0.1

1

10

100

1000

10000

100000

0 0.5 1 1.5 2 2.5

Wavelength (m)

Bac

kgro

un

d (

g se

c-1)

Zodiacal light

Paranal sky

S/N = t1/2A h

F

(F + B)1/2

1/2( )

D = 6.5 m = 0.3”

D = 2 m = /D

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GOODs Legacy & Treasury Programs ObservationsObservations

300 arcmin300 arcmin22 in two fields: HDF-N, CDF-S in two fields: HDF-N, CDF-S SIRTF: 3.6-24 µm (IRAC+MIPS), 600 hoursSIRTF: 3.6-24 µm (IRAC+MIPS), 600 hours HST: 4 bands, 500 orbits ACS, near HDF depthHST: 4 bands, 500 orbits ACS, near HDF depth Chandra: 2x10Chandra: 2x1066 sec imaging; XMM: ~5x10 sec imaging; XMM: ~5x1055 sec imaging sec imaging

North South

ScienceScience Evolution of galaxies, 1 < z < 6Evolution of galaxies, 1 < z < 6 SN Ia detection via schedulingSN Ia detection via scheduling AGN morphologiesAGN morphologies Potential upgrades: wider fields for AGN, weak-lensing, DEEP fieldsPotential upgrades: wider fields for AGN, weak-lensing, DEEP fields

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All sky surveys

Space advantages:Space advantages: Low BLow B Small Small over large FOV over large FOV PSF stabilityPSF stability Photometric stabilityPhotometric stability Full sky coverageFull sky coverage 24 hr operation24 hr operation

(m) 10 mag t(sec) 4(days) 10 Mag t(sec) 4(days)0.35 26.4 3.0 1.4 30.7 223 1070.45 27.0 3.0 1.4 28.9 72 340.55 26.1 3.0 1.4 28.1 53 250.70 25.3 3.0 1.4 27.3 41 190.90 25.1 3.0 1.4 26.8 42 201.22 20.0 3.0 1.4 24.9 59 281.65 17.9 3.0 1.4 24.4 108 522.10 16.5 3.0 1.4 23.9 176 84

6.5m Ground 2m Space

Ground advantagesGround advantages Large area telescopesLarge area telescopes Upgradable detectors Upgradable detectors

(large FOV)(large FOV) High survey speed at BLIPHigh survey speed at BLIP

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Ideal limiting magnitudes

15

20

25

30

35

0 1 2 3

Wavelength (m)

Lim

itin

g M

ag

nit

ud

e

2m spacetelescope

6.5m LSST

Space-survey science:Space-survey science: Earth-crossing asteroids (Earth-crossing asteroids (sens.sens.)) Kuiper-belt objects (Kuiper-belt objects (sens., sens., )) Transient sourcesTransient sources

Supernovae (e.g. SN Ia) (Supernovae (e.g. SN Ia) (sens.sens.))Micro-lensing sources (Micro-lensing sources (# stars# stars))

Dwarf stars: white, brown (Dwarf stars: white, brown (senssens.).) Quantify weak lensing in distant Quantify weak lensing in distant

galaxies (galaxies (small small , stable PSF, stable PSF)) Parallaxes of faint stars (Parallaxes of faint stars (sens.sens.)) Rare objects (survey to Rare objects (survey to R ~ 27R ~ 27mm)) Eclipses of exo-planets (Eclipses of exo-planets (photometric photometric

stabilitystability))

High z SN

DMT 8.4m

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-40 0 40 80 120

t (days)

28

27

26

25

24

23

I (mag)

z = 1.7

z = 1.4

z = 1.0

SN Ia Detection rate

WFPC2: 2 orbit

ACS: 2 orbit

LSST 4

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SN 1998ff

A. Riess, F. Boffi & SNaZ Team

0.080”

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HD 209458b: Exoplanet eclipse

3 hours

Ingress Eclipse Egress

1σ ~ 2x10-4

5x10-4

Kepler selected as Discovery-class Mission

courtesy Brown et al. (2001)

1/9/2002 10

• Has a metallicity (abundance of elements heavier than helium) about one third that of the sun

HST/WFPC2

DSS

Globular Cluster Globular Cluster 47 Tucanae47 Tucanae

Contains about 106 stars, at ~11 Gyr

courtesy R. Gilliland et al. (2001)

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NEO Hazardcourtesy DMT consortiumhttp://dmtelescope.org/science.html

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Cumulative Distribution of NEAs

12 14 16 18 20 22

10

100

1000

10000

100000

# of NEAs largerthan 1km

5km 200m1km

Cu

mu

lati

ve #

of

NE

As

larg

er

tha

n H

H

All Known NEAs LINEAR Discoveries (43%) Min theory (500) Max theory (2100) Known (424)

300m

4,000 –77,000

Follow-up problem ?

courtesy DMT consortiumhttp://dmtelescope.org/science.html

1/9/2002 13

Planned surveys with spacecraft Galaxy, AGN evolutionGalaxy, AGN evolution

HST/ACS, NGSTHST/ACS, NGST Supernovae, Supernovae,

HST/ACS+NICMOS, SNAPHST/ACS+NICMOS, SNAP Eclipsing extra-solar planetary systemsEclipsing extra-solar planetary systems

KeplerKepler Astrometric surveysAstrometric surveys

Hipparcos, SIM, GAIAHipparcos, SIM, GAIA

~ /DB ~ Zodiacal lightFOV ~ optics limit

(m) 10 Mag t(sec)

0.35 30.7 2230.45 28.9 720.55 28.1 530.70 27.3 410.90 26.8 421.22 24.9 591.65 24.4 1082.10 23.9 176

2m Space