uncovering%the%firstgalaxies%in% the%frontier%fields · 12november2014...
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Yale Hubble Frontier Fields Workshop
Uncovering the First Galaxies in the Frontier Fields
Rachael Livermore University of Texas at Austin
12 November 2014 1
Yale Hubble Frontier Fields Workshop
The Problem: It is difficult to detect faint sources in the most magnified regions of cluster fields
Ishigaki+ 2014 Atek+ 2014
12 November 2014 2
Yale Hubble Frontier Fields Workshop
The Problem: It is difficult to detect faint sources in the most magnified regions of cluster fields
Ishigaki+ 2014 Atek+ 2014
Critical line at z=7 denotes region of
maximum magnification
12 November 2014 2
Yale Hubble Frontier Fields Workshop
The Problem: It is difficult to detect faint sources in the most magnified regions of cluster fields
Ishigaki+ 2014 Atek+ 2014
Critical line at z=7 denotes region of
maximum magnification
High-‐z sources concentrated around outskirts of cluster where magnification
➔ 1
12 November 2014 2
Yale Hubble Frontier Fields Workshop
The highly magnified regions represent the smallest volume…
…and the bright foreground galaxies and intracluster light limit the depth of the image in the central
regions
12 November 2014 3
Yale Hubble Frontier Fields Workshop
The highly magnified regions represent the smallest volume…
…and the bright foreground galaxies and intracluster light limit the depth of the image in the central
regions
12 November 2014 3
Yale Hubble Frontier Fields Workshop
The highly magnified regions represent the smallest volume…
…and the bright foreground galaxies and intracluster light limit the depth of the image in the central
regions
12 November 2014 3
Yale Hubble Frontier Fields Workshop12 November 2014 4
Wavelet Decomposition
Yale Hubble Frontier Fields Workshop12 November 2014 4
Wavelet Decomposition
Yale Hubble Frontier Fields Workshop12 November 2014 4
Wavelet Decomposition
Yale Hubble Frontier Fields Workshop12 November 2014 4
Wavelet Decomposition
Yale Hubble Frontier Fields Workshop12 November 2014 4
Wavelet Decomposition
Yale Hubble Frontier Fields Workshop12 November 2014 4
Wavelet Decomposition
Yale Hubble Frontier Fields Workshop12 November 2014 4
Wavelet Decomposition
Yale Hubble Frontier Fields Workshop12 November 2014 4
Wavelet Decomposition
Yale Hubble Frontier Fields Workshop12 November 2014 4
Wavelet Decomposition
Yale Hubble Frontier Fields Workshop12 November 2014 4
Wavelet Decomposition
Yale Hubble Frontier Fields Workshop12 November 2014 4
Wavelet Decomposition
Yale Hubble Frontier Fields Workshop12 November 2014 5
Wavelet Decomposition
Yale Hubble Frontier Fields Workshop12 November 2014 5
Wavelet Decomposition
Yale Hubble Frontier Fields Workshop12 November 2014 5
Wavelet Decomposition
Cluster modelWavelet-‐subtracted image
Yale Hubble Frontier Fields Workshop12 November 2014 6
Removing the foreground light makes it easier to detect small, faint objects behind the cluster
Yale Hubble Frontier Fields Workshop12 November 2014 7
Simulations show we recover more faint sources when wavelet-‐subtracted images
are used for detection
Fake source input magnitude
Fractio
n of so
urces recovered
Original (unsubtracted)
image
Increasingly aggressive subtraction
Yale Hubble Frontier Fields Workshop12 November 2014 7
Simulations show we recover more faint sources when wavelet-‐subtracted images
are used for detection
Fake source input magnitude
Fractio
n of so
urces recovered
Original (unsubtracted)
image
Increasingly aggressive subtraction
Bright sources are lost in the subtraction, but
fainter sources become easier to recover
Yale Hubble Frontier Fields Workshop12 November 2014 8
Wavelet subtraction improves depth across the field, particularly the crucial
central region
Original image
Yale Hubble Frontier Fields Workshop12 November 2014 8
Wavelet subtraction improves depth across the field, particularly the crucial
central region
Original image Subtraction scale 0
Yale Hubble Frontier Fields Workshop12 November 2014 8
Wavelet subtraction improves depth across the field, particularly the crucial
central region
Original image Subtraction scale 1
Yale Hubble Frontier Fields Workshop12 November 2014 8
Wavelet subtraction improves depth across the field, particularly the crucial
central region
Original image Subtraction scale 2
Yale Hubble Frontier Fields Workshop12 November 2014 8
Wavelet subtraction improves depth across the field, particularly the crucial
central region
Original image Subtraction scale 3
Yale Hubble Frontier Fields Workshop12 November 2014 8
Wavelet subtraction improves depth across the field, particularly the crucial
central region
Original image Subtraction scale 4
Yale Hubble Frontier Fields Workshop12 November 2014 8
Wavelet subtraction improves depth across the field, particularly the crucial
central region
Original image Subtraction scale 5
Yale Hubble Frontier Fields Workshop12 November 2014 9
Up to scale 5, flux recovery remains robust if the original image is used for
photometry
Fake source input magnitude
Inpu
t – Recovered
magnitude
Yale Hubble Frontier Fields Workshop
Candidate selection in Abell 2744
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Yale Hubble Frontier Fields Workshop
z ~ 7
Candidate selection in Abell 2744
12 November 2014 10
Yale Hubble Frontier Fields Workshop
z ~ 7z ~ 8
Candidate selection in Abell 2744
12 November 2014 10
Yale Hubble Frontier Fields Workshop
z ~ 7z ~ 8z ~ 9
Candidate selection in Abell 2744
12 November 2014 10
Yale Hubble Frontier Fields Workshop
z ~ 7z ~ 8z ~ 9
Candidate selection in Abell 2744
12 November 2014 10
We find 53 galaxies at z ≥ 7: 34 at z ≈ 7 16 at z ≈ 8 3 at z ≈ 9
Yale Hubble Frontier Fields Workshop
Candidate selection in MACS0416
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Yale Hubble Frontier Fields Workshop
z ~ 7
Candidate selection in MACS0416
12 November 2014 11
Yale Hubble Frontier Fields Workshop
z ~ 7z ~ 8
Candidate selection in MACS0416
12 November 2014 11
Yale Hubble Frontier Fields Workshop
z ~ 7z ~ 8z ~ 9
Candidate selection in MACS0416
12 November 2014 11
Yale Hubble Frontier Fields Workshop
z ~ 7z ~ 8z ~ 9
Candidate selection in MACS0416
12 November 2014 11
We find 23 galaxies at z ≥ 7: 7 at z ≈ 7 8 at z ≈ 8 8 at z ≈ 9
Yale Hubble Frontier Fields Workshop
Observed number counts at z ≥ 7
z ≈ 7
Observed mag
n
z ≈ 8 z ≈ 9
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Yale Hubble Frontier Fields Workshop
Observed number counts at z ≥ 7
z ≈ 7
Observed mag
n
z ≈ 8 z ≈ 9
12 November 2014 12
Yale Hubble Frontier Fields Workshop
Observed number counts at z ≥ 7
z ≈ 7
Observed mag
n
z ≈ 8 z ≈ 9
12 November 2014 12
Yale Hubble Frontier Fields Workshop
Observed number counts at z ≥ 7
z ≈ 7
Observed mag
n
z ≈ 8 z ≈ 9
12 November 2014 12
Wavelet subtraction enables us to detect more faint
galaxies
Yale Hubble Frontier Fields Workshop
Observed magnitudes of z>7 candidates
12 November 2014 13
Abell 2744 MACS 0416
H-‐band mag (observed)H-‐band mag (observed)
n n
z ~ 7z ~ 8z ~ 9
Yale Hubble Frontier Fields Workshop
Observed magnitudes of z>7 candidates
12 November 2014 13
Abell 2744 MACS 0416
H-‐band mag (observed)H-‐band mag (observed)
n n
z ~ 7z ~ 8z ~ 9
Yale Hubble Frontier Fields Workshop
Observed magnitudes of z>7 candidates
12 November 2014 13
Abell 2744 MACS 0416
H-‐band mag (observed)H-‐band mag (observed)
n n
z ~ 7z ~ 8z ~ 9
Yale Hubble Frontier Fields Workshop
Magnification
12 November 2014 14
Yale Hubble Frontier Fields Workshop
Magnification
12 November 2014 14
Yale Hubble Frontier Fields Workshop
Magnification
12 November 2014 14
CATS
Yale Hubble Frontier Fields Workshop
Magnification
12 November 2014 14
Bradac
Yale Hubble Frontier Fields Workshop
Magnification
12 November 2014 14
Merten
Yale Hubble Frontier Fields Workshop
Magnification
12 November 2014 14
Sharon
Yale Hubble Frontier Fields Workshop
Magnification
12 November 2014 14
Williams
Yale Hubble Frontier Fields Workshop
Magnification
12 November 2014 14
Zitrin-‐LTM
Yale Hubble Frontier Fields Workshop
Magnification
12 November 2014 14
Zitrin-‐NFW
Yale Hubble Frontier Fields Workshop
Magnification
12 November 2014 14
Zitrin-‐NFW
The photo-‐z is the dominant source of error on the
magnification, but model uncertainties are important at
high magnification
Yale Hubble Frontier Fields Workshop
Intrinsic magnitudes of z ≥ 7 candidates
12 November 2014 15
Abell 2744 MACS 0416
H-‐band mag (intrinsic)H-‐band mag (intrinsic)
n n
Yale Hubble Frontier Fields Workshop
Intrinsic magnitudes of z ≥ 7 candidates
12 November 2014 15
Abell 2744 MACS 0416
H-‐band mag (intrinsic)H-‐band mag (intrinsic)
n n
Yale Hubble Frontier Fields Workshop
Intrinsic magnitudes of z ≥ 7 candidates
12 November 2014 15
Abell 2744 MACS 0416
H-‐band mag (intrinsic)H-‐band mag (intrinsic)
n n
Yale Hubble Frontier Fields Workshop
Summary
• We are using wavelet decomposition to remove foreground cluster light
!• We find this increases the depth of the image without impacting the
photometry !• Early results indicate 78 lensed z ≥ 7 galaxies in the first two clusters
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