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The Rest-Frame Optical Spectrum of MS 1512-cB58

H. I. Teplitz·I. S. McLean·E. E. Becklin·D. F. Figer·A. M. Gilbert·J. R. Graham·J. E. Larkin·N. A. Levenson·M. K. Wilcox
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Abstract

Moderate resolution, near-IR spectroscopy of MS1512-cB58 is presented, obtained during commissioning of the the Near IR Spectrometer (NIRSPEC) on the Keck II telescope. The strong lensing of this z=2.72 galaxy by the foreground cluster MS1512+36 makes it the best candidate for detailed study of the rest-frame optical properties of Lyman Break Galaxies. A redshift of z=2.7290+/-0.0007 is inferred from the emission lines, in contrast to the z=2.7233 calculated from UV observations of interstellar absorption lines. Using the Balmer line ratios, we find an extinction of E(B-V)=0.27. Using the line strengths, we infer an SFR=620+/-18 Msun/yr (H_0=75, q_0=0.1, Lambda =0), a factor of 2 higher than that measured from narrow-band imaging observations of the galaxy, but a factor of almost 4 lower than the SFR inferred from the UV continuum luminosity. The width of the Balmer lines yields a mass of M_vir=1.2x10^10 Msun. We find that the oxygen abundance is 1/3 solar, in good agreement with other estimates of the metallicity. However, we infer a high nitrogen abundance, which may argue for the presence of an older stellar population.

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H. I. Teplitz, I. S. McLean, E. E. Becklin, D. F. Figer, A. M. Gilbert, J. R. Graham, J. E. Larkin, N. A. Levenson, M. K. Wilcox. 2000-02-28. The Rest-Frame Optical Spectrum of MS 1512-cB58. https://doi.org/10.1086/312595

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