Evidence against a redshift z > 6 for the galaxy STIS123627+621755

Article

关键词: LUMINOSITY DENSITY;    WHITE-DWARF;    FIELD;    UNIVERSE;   

DOI  :  10.1038/35046027

来源: SCIE

【 摘 要 】

The identification of galaxies at extreme distances provides the most direct information about the earliest phases of galaxy formation. But at redshifts z>5 even the most luminous galaxies appear faint; the interpretation of low signal-to-noise ratio data is difficult and misidentifications do occur. Here we report optical and near-infrared observations of the source STIS123627+621755, which was previously suggested to be at a redshift of 6.68 (ref. 1). At that redshift, and with the reported 1 spectral energy distribution, the galaxy should be essentially invisible at wavelengths less than 9,300 Angstrom, because the intervening intergalactic medium absorbs almost all light energetic enough to ionize neutral hydrogen-that is, with wavelengths less than the redshifted Lyman limit of lambda = (1 + z) x 912 Angstrom. At near-infrared wavelengths, however, the galaxy should be relatively bright. Here we report a detection of the galaxy at 6,700 Angstrom and a non-detection at a wavelength of 1.2 mum, contrary to expectations for z approximate to 6.68. The data conservatively require that STIS123627+621755 has a redshift z< 6.

【 授权许可】

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