HUBBLE SPACE TELESCOPE/ADVANCED CAMERA FOR SURVEYS MORPHOLOGY OF Ly{alpha} EMITTERS AT REDSHIFT 5.7 IN THE COSMOS FIELD

Journal Article · Thu Aug 20 00:00:00 EDT 2009 · Astrophysical Journal

DOI:https://doi.org/10.1088/0004-637X/701/2/915; COUNTRY OF INPUT: INTERNATIONAL ATOMIC ENERGY AGENCY (IAEA)· OSTI ID:21319597

Taniguchi, Y; Nagao, T; Shioya, Y; Saito, T ^[1]; Murayama, T; Sasaki, S S ^[2]; Scoville, N Z; Capak, P; Salvato, M; Ellis, R S ^[3]; Ideue, Y; Nakajima, A; Matsuoka, K ^[4]; Sanders, D B ^[5]; Mobasher, B ^[6]; Aussel, H ^[7]; Koekemoer, A ^[8]; Carilli, C ^[9]; Cimatti, A ^[10]; Garilli, B ^[11]

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1. Research Center for Space and Cosmic Evolution, Ehime University, Bunkyo-cho 2-5, Matsuyama 790-8577 (Japan)
2. Astronomical Institute, Graduate School of Science, Tohoku University, Aramaki, Aoba, Sendai 980-8578 (Japan)
3. Department of Astronomy, MS 105-24, California Institute of Technology, Pasadena, CA 91125 (United States)
4. Graduate School of Science and Engineering, Ehime University, Bunkyo-cho, Matsuyama 790-8577 (Japan)
5. Institute for Astronomy, University of Hawaii, 2680 Woodlawn Drive, HI 96822 (United States)
6. Department of Physics and Astronomy, University of California, Riverside, CA 92521 (United States)
7. CEA/DSM-CNRS, Universite Paris Diderot, DAPNIA/SAp, Orme des Merisiers, 91191 Gif-sur-Yvette (France)
8. Space Telescope Science Institute, 3700 San Martin Drive, Baltimore, MD 21218 (United States)
9. National Radio Astronomy Observatory, P.O. Box 0, Socorro, NM 87801-0387 (United States)
10. Dipartamento di Astronmia, Universita di Bologna (Italy)
11. INAF, Istituto di Astrofisica Spaziale e Fisica Cosmica, Sezione di Milano, via Bassini 15, 20133 Milano (Italy)

We present detailed morphological properties of Ly{alpha} emitters (LAEs) at z {approx} 5.7 in the COSMOS field based on Hubble Space Telescope Advanced Camera for Surveys (ACS) data. The ACS imaging in the F814W filter covered 85 LAEs of the 119 LAEs identified in the full two square degree field, and 47 LAEs of them are detected in the ACS images. Nearly half of them are spatially extended with a size larger than 0.15 arcsec ({approx}0.88 kpc at z = 5.7) and up to 0.4 arcsec ({approx}2.5 kpc at z = 5.7). The others are nearly unresolved compact objects. Two LAEs show double-component structures indicating interaction or merging of building components to form more massive galaxies. By stacking the ACS images of all the detected sources, we obtain a Sersic parameter of n {approx} 0.7 with a half-light radius of 0.13 arcsec (0.76 kpc), suggesting that the majority of ACS detected LAEs have not spheroidal-like but disk-like or irregular light profiles. Comparing ACS F814W magnitudes (I {sub 814}) with Subaru/Suprime-Cam magnitudes in the NB816, i', and z' bands, we find that the ACS imaging in the F814W band mainly probes UV continuum rather than Ly{alpha} line emission. UV continuum sizes tend to be larger for LAEs with larger Ly{alpha} emission regions as traced by the NB816 imaging. The nondetection of 38 LAEs in the ACS images is likely due to the fact that their surface brightness is too low both in the UV continuum and Ly{alpha} emission. Estimating I {sub 814} for the ACS-undetected LAEs from the z' and NB816 magnitudes, we find that 16 of these are probably LAEs with a size larger than 0.15 arcsec in UV continuum. All these results suggest that our LAE sample contains systematically larger LAEs in UV continuum size than those previously studied at z {approx} 6.

• OSTI ID: 21319597
• Journal Information: Astrophysical Journal, Vol. 701, Issue 2; Other Information: DOI: 10.1088/0004-637X/701/2/915; Country of input: International Atomic Energy Agency (IAEA); ISSN 0004-637X
• Country of Publication: United States
• Language: English

Related Subjects

79 ASTROPHYSICS
COSMOLOGY AND ASTRONOMY
BRIGHTNESS
CAMERAS
COSMOLOGY
EMISSION
GALACTIC EVOLUTION
GALAXIES
IMAGES
RED SHIFT
TELESCOPES
UNIVERSE