The Spectral Energy Distribution of the Z = 3 Quasar: HS 1946+7658

January 1995 • 1995ApJ...438..643K

Authors • Kuhn, O. • Bechtold, J. • Cutri, R. • Elvis, M. • Rieke, M.

Abstract • For the bright z = 3.02 radio-quiet quasar, HS 1946 + 7658, we have obtained radio to X-ray data within the past year: 5 GHz and 1415 MHz data from the VLA; IR photometry at J, H, K, L' (3.4 micron) and N; IR spectroscopy; UBVRI photometry; optical spectrophotometry and high- resolution spectra; and an X-ray spectrum from the ROSAT PSPC. The spectral energy distribution (SED) constructed from these data is compared to the mean SED for a set of low-redshift quasars, and while they appear generally similar, there are several differences. In relation to the low-redshift mean, the SED of HS 1946 + 7658 shows (1) only an upper limit at 10 microns (a rest wavelength of 2.5 microns), indicating that HS 1946 + 7658 does not have a strong near-IR excess such as hot dust would produce; (2) relatively weak Fe II and Balmer continuum emission at ~3000 A; and (3) a steeper turndown shortward of Lyα, even after correction for the Lyα forest absorption lines.

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