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arXiv 1104.2035astro-ph.CO
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透过镜子:Abell 1703背后z~7的明亮高磁星系候选者

Through the Looking Glass: Bright, Highly Magnified Galaxy Candidates at z~7 Behind Abell 1703

L. D. Bradley, R. J. Bouwens, A. Zitrin, R. Smit, D. Coe, H. C. Ford, W. Zheng, G. D. Illingworth, N. Benítez, T. J. Broadhurst

摘要:

报道了哈勃空间望远镜(HST)WFC 3对Abell 1703的成像结果,发现了7个z~7的强透镜莱曼破裂星系(LBG)候选星系。最亮的候选星系被称为A1703-zD 1,在WFC 3/IR F160 W波段的观测(透镜)星等为24.0 AB(26 sigma),比最近报道的子弹星系团后面的z_850-dropout候选星系亮0.2等,比之前最亮的已知z~7.6星系A1689-zD 1亮0.7等。星团放大率约为9,这个源的内禀星等为H_160 = 26.4 AB,有一个1.7等的强z_850 - J_125折点,光度红移为z~6.7。此外,我们还发现了其他六个明亮的LBG候选者,其H_160带的幅度为24.9-26.4,光度红移z~6.4 - 8.8,放大倍率μ ~3-40。A1703-zD 1和A1703-zD 4的恒星星族与ACS、WFC 3/IR和\Spitzer /IRAC数据拟合后得到的恒星质量为(0.7 - 3.0)x 10^{9} M太阳,恒星年龄为5- 1.8亿年,恒星形成速率约为7.8 M太阳/年,红化程度较低,A_V <= 0.7。异常明亮的候选者A1703-zD 1的源平面重建显示出一个扩展的结构,在z~6.7源平面上跨越~ 4kpc,并显示出三个半径为r~ 0.4kpc的恒星形成结。

英文摘要:

We report the discovery of seven strongly lensed Lyman break galaxy (LBG) candidates at z~7 detected in Hubble Space Telescope (HST) Wide Field Camera 3 (WFC3) imaging of Abell 1703. The brightest candidate, called A1703-zD1, has an observed (lensed) magnitude of 24.0 AB (26 sigma) in the WFC3/IR F160W band, making it 0.2 magnitudes brighter than the z_850-dropout candidate recently reported behind the Bullet Cluster and 0.7 magnitudes brighter than the previously brightest known z~7.6 galaxy, A1689-zD1. With a cluster magnification of ~9, this source has an intrinsic magnitude of H_160 = 26.4 AB, a strong z_850 - J_125 break of 1.7 magnitudes, and a photometric redshift of z~6.7. Additionally, we find six other bright LBG candidates with H_160 band magnitudes of 24.9-26.4, photometric redshifts z~6.4 - 8.8, and magnifications mu~3-40. Stellar population fits to the ACS, WFC3/IR, and \Spitzer/IRAC data for A1703-zD1 and A1703-zD4 yield stellar masses (0.7 - 3.0) x 10^{9} M_sun, stellar ages 5-180 Myr, and star-formation rates ~7.8 M_sun/yr, and low reddening with A_V <= 0.7. The source-plane reconstruction of the exceptionally bright candidate A1703-zD1 exhibits an extended structure, spanning ~4 kpc in the z~6.7 source plane, and shows three resolved star-forming knots of radius r~0.4 kpc.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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