CLASH: Extreme Emission-line Galaxies and Their Implication on Selection of High-redshift Galaxies

Abstract

We utilize the Cluster Lensing And Supernova survey with Hubble observations of 25 clusters to search for extreme emission-line galaxies (EELGs). The selections are carried out in two central bands: F105W (Y_(105)) and F125W (J_(125)), as the flux of the central bands could be enhanced by the presence of [O III] λλ4959, 5007 at redshifts of ~0.93-1.14 and 1.57-1.79, respectively. The multiband observations help to constrain the equivalent widths (EWs) of emission lines. Thanks to cluster lensing, we are able to identify 52 candidates down to an intrinsic limiting magnitude of 28.5 and to a rest-frame [O III] λλ4959, 5007 EW of ≃ 3700 Å. Our samples include a number of EELGs at lower luminosities that are missed in other surveys, and the extremely high EW can only be found in such faint galaxies. These EELGs can mimic a dropout feature similar to that of high-redshift galaxies and contaminate the color-color selection of high-redshift galaxies when the signal-to-noise ratio is limited or the band coverage is incomplete.

Additional Information

© 2015 American Astronomical Society. Received 2014 July 6; accepted 2014 December 22; published 2015 February 25. The CLASH program (GO-12065) is based on observations made with the NASA/ESA Hubble Space Telescope. The Space Telescope Science Institute is operated by the Association of Universities for Research in Astronomy, Inc., under NASA Contract NAS 5-26555. J.X.W. acknowledges support from Chinese NSF (grant Nos. 11233002 and 11421303) and the Strategic Priority Research Program "The Emergence of Cosmological Structures" of the Chinese Academy of Sciences (Grant XDB09000000). Facility: HST (ACS,WFC3)

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Published - 0004-637X_801_1_12.pdf

Submitted - 1412.7909v1.pdf

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