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Near Infrared Observations of a Redshift 4.92 Galaxy: Evidence for Significant Dust Absorption

B. T. Soifer·G. Neugebauer·M. Franx·K. Matthews·G. Illingworth
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Abstract

Near-infrared imaging and spectroscopy have been obtained of the gravitationally lensed galaxy at z=4.92 discovered in HST images by Franx et al. (1997). Images at 1.2, 1.6 and 2.2 microns show the same arc morphology as the HST images. The spectrum with resolution λ/ Δλ~ 70 shows no emission lines with equivalent width stronger than 100 A in the rest frame wavelength range 0.34 to 0.40 microns. In particular, [OII]3727 A and [NeIII]3869 A are not seen. The energy distribution is quite blue, as expected for a young stellar population with the observed Ly alpha flux. The spectral energy distribution can be fit satisfactorily for such a young stellar population when absorption by dust is included. The models imply a reddening 0.1 mag < E(B-V) < 0.4 mag. The stellar mass of the lensed galaxy lies in the range of 2 to 16 x 10^9 Msun. This is significantly higher than estimates based on the HST data alone. Our data imply that absorption by dust is important to redshifts of ~5.

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B. T. Soifer, G. Neugebauer, M. Franx, K. Matthews, G. Illingworth. 1998-05-16. Near Infrared Observations of a Redshift 4.92 Galaxy: Evidence for Significant Dust Absorption. https://doi.org/10.1086/311462

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