The sizes of z ∼ 6–8 lensed galaxies from the Hubble Frontier Fields Abell 2744 data

Journal Article · Sun May 10 04:00:00 EDT 2015 · Astrophysical Journal

DOI:https://doi.org/10.1088/0004-637X/804/2/103· OSTI ID:22883221

Kawamata, Ryota; Shimasaku, Kazuhiro ^[1]; Ishigaki, Masafumi; Oguri, Masamune ^[2]; Ouchi, Masami ^[3]

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1. Department of Astronomy, Graduate School of Science, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033 (Japan)
2. Department of Physics, Graduate School of Science, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033 (Japan)
3. Institute for Cosmic Ray Research, The University of Tokyo, 5-1-5 Kashiwanoha, Kashiwa, Chiba 277-8582 (Japan)

We investigate the sizes of z ∼ 6–8 dropout galaxies using the complete data of the Abell 2744 cluster and parallel fields in the Hubble Frontier Fields program. By directly fitting light profiles of observed galaxies with lensing-distorted Sérsic profiles on the image plane with the glafic software, we accurately measure intrinsic sizes of 31 z ∼ 6–7 and 8 z∼8 galaxies, including those as faint as M{sub UV}≃−16.6. We find that half-light radii r{sub e} positively correlates with UV luminosity at each redshift, although the correlation is not very tight. The largest (r{sub e}>0.8 kpc) galaxies are mostly red in UV color while the smallest (r{sub e}<0.08 kpc) ones tend to be blue. We also find that galaxies with multiple cores tend to be brighter. Combined with previous results at 2.5≲z≲12, our result confirms that the average r{sub e} of bright ((0.3–1)L{sub z=3}{sup ∗}) galaxies scales as r{sub e}∝(1+z){sup −m} with m=1.24±0.1. We find that the ratio of r{sub e} to virial radius is virtually constant at 3.3 ± 0.1% over a wide redshift range, where the virial radii of hosting dark matter halos are derived based on the abundance matching. This constant ratio is consistent with the disk formation model by Mo et al. with j{sub d}∼m{sub d}, where j{sub d} and m{sub d} are the fractions of the angular momentum and mass within halos confined in the disks. A comparison with various types of local galaxies indicates that our galaxies are most similar to circumnuclear star-forming regions of barred galaxies in the sense that a sizable amount of stars are forming in a very small area.

• OSTI ID: 22883221
• Journal Information: Astrophysical Journal, Journal Name: Astrophysical Journal Journal Issue: 2 Vol. 804; ISSN ASJOAB; ISSN 0004-637X
• Country of Publication: United Kingdom
• Language: English

Related Subjects

79 ASTRONOMY AND ASTROPHYSICS
ANGULAR MOMENTUM
COMPARATIVE EVALUATIONS
COMPUTERIZED SIMULATION
GALACTIC EVOLUTION
GRAVITATIONAL LENSES
LUMINOSITY
MASS
MILKY WAY
NONLUMINOUS MATTER
PHOTOMETRY
RED SHIFT
STARS