Abstract
Using Hubble Space Telescope (HST) and Spitzer IRAC imaging, we report the discovery of a very bright strongly lensed Lyman break galaxy (LBG) candidate atz ∼ 7.6 in the field of the massive galaxy cluster Abell 1689 (z = 0.18). The galaxy candidate, which we refer to as A1689-zD1, shows a strong z 850 - J110 break of at least 2.2 mag and is completely undetected (<1 σ) in HST Advanced Camera for Surveys (ACS) g 475, r625, i775, and Z850 data. These properties, combined with the very blue J110 - H160 and H160 - [4.5 μ] colors, are exactly the properties of an z ∼ 7.6 LBG, and can only be reasonably fit by a star-forming galaxy at z = 7.6 ± 0.4 (χv2 = 1.1). Attempts to reproduce these properties with a model galaxy at z < 4 yield particularly poor fits (χv2 ≥ 25). A1689-zD1 has an observed (lensed) magnitude of 24.7 AB (8 σ) in the NICMOS H160 band and is ∼1.3 mag brighter than the brightest known z850-dropout galaxy. When corrected for the cluster magnification of ∼9.3 at z ∼ 7.6, the candidate has an intrinsic magnitude of H160 = 27.1 AB, or about an L* galaxy atz ∼ 7.6. The source-plane deprojection shows that the star formation is occurring in compact knots of size ≲300 pc. The best-fit stellar population synthesis models yield a median redshift of 7.6, stellar masses (1.6-3.9) × 109 M⊙, stellar ages 45-320 Myr, star formation rates ≲7.6 M⊙ yr_1, and low reddening with Av ≤; 0.3. These properties are generally similar to those of LBGs found atz ∼ 5-6. The inferred stellar ages suggest a formation redshift of z ∼ 8-10 (t ≲ 0.63 Gyr). A1689-zD1 is the brightest observed, highly reliable z > 7.0 galaxy candidate found to date.
| Original language | English (US) |
|---|---|
| Pages (from-to) | 647-654 |
| Number of pages | 8 |
| Journal | Astrophysical Journal |
| Volume | 678 |
| Issue number | 2 |
| DOIs | |
| State | Published - May 10 2008 |
| Externally published | Yes |
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Keywords
- Cosmology: observations
- Galaxies: evolution
- Galaxies: formation galaxies: high-redshift
ASJC Scopus subject areas
- Space and Planetary Science
Cite this
Discovery of a very bright strongly lensed galaxy candidate at z ≈ 7.6. / Bradley, L. D.; Bouwens, R. J.; Ford, H. C.; Illingworth, G. D.; Jee, M. J.; Benítez, N.; Broadhurst, T. J.; Franx, M.; Frye, Brenda Louise; Infante, L.; Motta, V.; Rosati, P.; White, R. L.; Zheng, W.
In: Astrophysical Journal, Vol. 678, No. 2, 10.05.2008, p. 647-654.Research output: Contribution to journal › Article
}
TY - JOUR
T1 - Discovery of a very bright strongly lensed galaxy candidate at z ≈ 7.6
AU - Bradley, L. D.
AU - Bouwens, R. J.
AU - Ford, H. C.
AU - Illingworth, G. D.
AU - Jee, M. J.
AU - Benítez, N.
AU - Broadhurst, T. J.
AU - Franx, M.
AU - Frye, Brenda Louise
AU - Infante, L.
AU - Motta, V.
AU - Rosati, P.
AU - White, R. L.
AU - Zheng, W.
PY - 2008/5/10
Y1 - 2008/5/10
N2 - Using Hubble Space Telescope (HST) and Spitzer IRAC imaging, we report the discovery of a very bright strongly lensed Lyman break galaxy (LBG) candidate atz ∼ 7.6 in the field of the massive galaxy cluster Abell 1689 (z = 0.18). The galaxy candidate, which we refer to as A1689-zD1, shows a strong z 850 - J110 break of at least 2.2 mag and is completely undetected (<1 σ) in HST Advanced Camera for Surveys (ACS) g 475, r625, i775, and Z850 data. These properties, combined with the very blue J110 - H160 and H160 - [4.5 μ] colors, are exactly the properties of an z ∼ 7.6 LBG, and can only be reasonably fit by a star-forming galaxy at z = 7.6 ± 0.4 (χv2 = 1.1). Attempts to reproduce these properties with a model galaxy at z < 4 yield particularly poor fits (χv2 ≥ 25). A1689-zD1 has an observed (lensed) magnitude of 24.7 AB (8 σ) in the NICMOS H160 band and is ∼1.3 mag brighter than the brightest known z850-dropout galaxy. When corrected for the cluster magnification of ∼9.3 at z ∼ 7.6, the candidate has an intrinsic magnitude of H160 = 27.1 AB, or about an L* galaxy atz ∼ 7.6. The source-plane deprojection shows that the star formation is occurring in compact knots of size ≲300 pc. The best-fit stellar population synthesis models yield a median redshift of 7.6, stellar masses (1.6-3.9) × 109 M⊙, stellar ages 45-320 Myr, star formation rates ≲7.6 M⊙ yr_1, and low reddening with Av ≤; 0.3. These properties are generally similar to those of LBGs found atz ∼ 5-6. The inferred stellar ages suggest a formation redshift of z ∼ 8-10 (t ≲ 0.63 Gyr). A1689-zD1 is the brightest observed, highly reliable z > 7.0 galaxy candidate found to date.
AB - Using Hubble Space Telescope (HST) and Spitzer IRAC imaging, we report the discovery of a very bright strongly lensed Lyman break galaxy (LBG) candidate atz ∼ 7.6 in the field of the massive galaxy cluster Abell 1689 (z = 0.18). The galaxy candidate, which we refer to as A1689-zD1, shows a strong z 850 - J110 break of at least 2.2 mag and is completely undetected (<1 σ) in HST Advanced Camera for Surveys (ACS) g 475, r625, i775, and Z850 data. These properties, combined with the very blue J110 - H160 and H160 - [4.5 μ] colors, are exactly the properties of an z ∼ 7.6 LBG, and can only be reasonably fit by a star-forming galaxy at z = 7.6 ± 0.4 (χv2 = 1.1). Attempts to reproduce these properties with a model galaxy at z < 4 yield particularly poor fits (χv2 ≥ 25). A1689-zD1 has an observed (lensed) magnitude of 24.7 AB (8 σ) in the NICMOS H160 band and is ∼1.3 mag brighter than the brightest known z850-dropout galaxy. When corrected for the cluster magnification of ∼9.3 at z ∼ 7.6, the candidate has an intrinsic magnitude of H160 = 27.1 AB, or about an L* galaxy atz ∼ 7.6. The source-plane deprojection shows that the star formation is occurring in compact knots of size ≲300 pc. The best-fit stellar population synthesis models yield a median redshift of 7.6, stellar masses (1.6-3.9) × 109 M⊙, stellar ages 45-320 Myr, star formation rates ≲7.6 M⊙ yr_1, and low reddening with Av ≤; 0.3. These properties are generally similar to those of LBGs found atz ∼ 5-6. The inferred stellar ages suggest a formation redshift of z ∼ 8-10 (t ≲ 0.63 Gyr). A1689-zD1 is the brightest observed, highly reliable z > 7.0 galaxy candidate found to date.
KW - Cosmology: observations
KW - Galaxies: evolution
KW - Galaxies: formation galaxies: high-redshift
UR - http://www.scopus.com/inward/record.url?scp=43949083005&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=43949083005&partnerID=8YFLogxK
U2 - 10.1086/533519
DO - 10.1086/533519
M3 - Article
AN - SCOPUS:43949083005
VL - 678
SP - 647
EP - 654
JO - Astrophysical Journal
JF - Astrophysical Journal
SN - 0004-637X
IS - 2
ER -