The z~10 Universe seen with the HST Pascal Oesch (Hubble Fellow, UC Santa Cruz) G.D. Illingworth, R. Bouwens, HUDF09 Team:V. Gonzalez, D. Magee, I. Labbé, M. Trenti, C.M. Carollo, P. van Dokkum, M. Franx, M. Stiavelli
CINC 11
P. Oesch, UCSC UCO/Lick Observatory
UC Davis, October 2011
The Reionization Epoch with HST
Hubble can now see out to z~10 CINC, UC Davis, October 2011
P. Oesch, UCSC UCO/Lick Observatory
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Installation of WFC3 on HST
6.5x larger field-of-view than previous NIR camera (NICMOS) 3-4x more sensitive than before 2x higher spatial resolution
➡ ~40x more efficient to explore the high-redshift universe CINC, UC Davis, October 2011
P. Oesch, UCSC UCO/Lick Observatory
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Evolution of UV LF to z~8 Bouwens et al. 2011b
Main Evolution: only in M* (0.33 mag per unit z) Faint-end Slopes are extremely steep (α ~ -2) CINC, UC Davis, October 2011
P. Oesch, UCSC UCO/Lick Observatory
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Pushing the Frontier to z~10
B435 V606
i775 z850 Y105
J125
H160
z~9.5 LBG 2
0.4
0.6
0.8
1 1.2 h [Angstrom]
1.4
1.6
1.8 4 x 10
Very challenging: z~10 galaxies expected to be extremely faint single band detections low-z dusty galaxies can exhibit similar colors
J125ïH160
logfi, thpt [arb. units]
At z~8: neutral IGM starts affecting J125 Can select z>9.5 galaxies as J-dropouts based on red J125-H160 colors
1.5
SF dustïfree SF E(BïV)=0.15
J125ïH160>1.2
1 0.5 0 ï0.5 0
CINC, UC Davis, October 2011
SSP 1Gyr Sbc Scd Irr
P. Oesch, UCSC UCO/Lick Observatory
2
4
z
6
8
10 5
Requirements on Data 24
mag [AB]
26
HUDF Limits ERS Limits ty
s u d .7
28
z=2
z=10 LBG
30 32
2m limits
0.5
1
Non-detection required
h [µm]
2
4
6
Non-detection required
deep J125 and H160 deeper data shortward of Lyα break CINC, UC Davis, October 2011
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The z~10 Search Fields
CDFS offers perfect data for z~10 search Large amount of public optical (ACS) and NIR (WFC3) data HUDF09 ERS CANDELS (Deep & Wide)
Total of 160 arcmin2 Reach to 26.9 - 29.4 AB mag We use 6 epoch CANDELS Deep data obtained until August 6 2011
CINC, UC Davis, October 2011
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Excluding Low-Redshift Contaminants ACS
IRAC
WFC3/IR
17 sources are found satisfying our HST selection criteria 16 out of these are dusty/evolved sources at intermediate redshift (z~2-4) These are identified by strong Spitzer IRAC detections (H160-[3.6]>2) z~2-4 interlopers
survey limits CANDELS/ERS
Surface Density [#/mag/arcmin2]
0.1 0.08 0.06 0.04 0.02 0 23
CINC, UC Davis, October 2011
24
25
H160,AB
26
27
Such red intermediate redshift sources appear to have a peaked LF Therefore: only one z~10 candidate found in the full WFC3/IR data over the CDFS! 28
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Bouwens et al. Nature, January 2011
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processing and pipeline generation for the WFC3/IR data. Author Information Reprints and permissions information is available at www.nature.com/reprints. The authors declare no competing financial interests. Readers are welcome to comment on the online version of this article at www.nature.com/nature. Correspondence and requests for materials should be addressed to R.J.B. (
[email protected]).
The z~10 Candidate in the HUDF
UDFj-39546284 H=28.9 J-H>2.0 Y
V+i+z
Year 2
28
H
3.6
4.5
Very faint: HAB=28.8±0.2 Small chance of being spurious:
6284
ear 1
J
25
Year 1
Epoch 1
50% random 13
Epoch 2
1st Year 13
It is detected at ~6σ It is visible at >2.5σ in 4 independent splits of the data
Year 2
Epoch 3
Epoch 4
Blue UV continuum: not detected in very deep IRAC data
50% random 2nd Year 13 14
Figure 1. Optical and near-infrared images of the candidate z ≈ 10 galaxy, UDFj-39546284, from the HUDF. Top row: the leftmost panel shows the HUDF ACS (V606 i775 z850 ) data26 ; the next
1 p(z)
zphot = 10.4±0.4 Small (<~10%) chance of being a low-z contaminant Planned HST data might help to further strengthen the high-z solution
mAB
25
0.5 0 0 2.5 5 7.5 10 12.5 z
27.5
30 HUDFjï39546284 0.5
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1
2 h [µm]
4
6
8 10
Constraints on z~10 LF 1.4
dNexp/0.25 mag
1.2 1 0.8
Expected # of z~10 Sources Total: 6.4 HUDF09: 3.4 HUDF09ï1: 1.1 HUDF09ï2: 1.3 WIDE Fields: 0.5
extrapolation to z~10
0.6 0.4 0.2 0 25
25.5
26
26.5
27
27.5 28 HH [mag] AB AB
Extrapolate low-z LF trends to z~10: expect to see 6 sources Even including cosmic variance: chance of finding one when expecting 6 is only ~6%
CINC, UC Davis, October 2011
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28.5
➡
29
29.5
30
Accelerated evolution of UV LF detected at ~2σ
11
Constraints on z~10 LF (II) ï1
10
ï2
10
ï3
10
ï4
LF
4 ~ z
ati l o p a extr
z~ o t on
6
10
ï5
z~
log q [magï1Mpcï3]
10
10
z~
8
z ~ 10 ï6
10
ï22
Wide Area
ï21
Three Wide Fields: limits are below z~8 CINC, UC Davis, October 2011
ï20
HUDF09ïP
ï19 MUV
HUDF
ï18
ï17
ï16
Three HUDF09 Fields: z~10 limits are below extrapolation P. Oesch, UCSC UCO/Lick Observatory
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26.5
JWST era
26 25.5
emp iric
>0.06L*(z=3)
th
25
eo r
al e
xtra
y
pol
atio n
24.5 24 23.5 3
4
5
6
7 8 Redshift
9
10
11
theory: Lacey+11, Trenti+11
log Luminosity Density [erg/s/Hz/Mpc3]
Accelerated Evolution of the UV Luminosity
12
Rapid build-up of UV luminosity in galaxies within only 170 Myr But: result is still uncertain (due to only 1 detection) needs confirmation with future deeper data (JWST!) CINC, UC Davis, October 2011
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Summary HST has detected a plausible z~10 candidate in the HUDF 6 sources were expected to be found in current WFC3/IR data over CDFS The upper limits on the z~10 UV LF are significantly below extrapolation of observed trends Indicates accelerated evolution of UV LF at M<-18 at z>8, at 2σ significance, including cosmic variance. The 170 Myr from z~10 to z~8 appears to be a time of rapid change in the galaxy population. Need JWST to robustly constrain accelerated evolution. z>9 is JWST territory. ➡ Save the JWST!
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