The Extragalactic Background Light (EBL) captures the total integrated emission from stars and galaxies throughout the cosmic history. The amplitude of the near-infrared EBL from space absolute photometry observations has been controversial and depends strongly on the modeling and subtraction of the Zodiacal light foreground. We report the first measurement of the diffuse background spectrum at 0.8-1.7 µm from the CIBER experiment. The observations were obtained with an absolute spectrometer over two flights in multiple sky fields to enable the subtraction of Zodiacal light, stars, terrestrial emission, and diffuse Galactic light. After subtracting foregrounds and accounting for systematic errors, we find the nominal EBL brightness, assuming the Kelsall Zodiacal light model, is 42.7 +11.9 −10.6 nW m −2 sr −1 at 1.4 µm. We also analyzed the data using the Wright Zodiacal light model, which results in a worse statistical fit to the data and an unphysical EBL, falling below the known background light from galaxies at λ <1.3 µm. Using a model-independent analysis based on the minimum EBL brightness, we find an EBL brightness of 28.7+5.1 −3.3 nWm −2 sr −1 at 1.4 µm. While the derived EBL amplitude strongly depends on the Zodiacal light model, we find that we cannot fit the spectral data to Zodiacal light, Galactic emission, and EBL from solely integrated galactic light from galaxy counts. The results require a new diffuse component, such as an additional foreground or an excess EBL with a redder spectrum than that of Zodiacal light.

We report measurements of the diffuse galactic light (DGL) spectrum in the near-infrared, spanning the wavelength range 0.95-1.65 μm by the Cosmic Infrared Background ExpeRiment. Using the low-resolution spectrometer calibrated for absolute spectro-photometry, we acquired long-slit spectral images of the total diffuse sky brightness toward six high-latitude fields spread over four sounding rocket flights. To separate the DGL spectrum from the total sky brightness, we correlated the spectral images with a 100 μm intensity map, which traces the dust column density in optically thin regions. The measured DGL spectrum shows no resolved features and is consistent with other DGL measurements in the optical and at near-infrared wavelengths longer than 1.8 μm. Our result implies that the continuum is consistently reproduced by models of scattered starlight in the Rayleigh scattering regime with a few large grains.

Autosomal dominant spinocerebellar ataxias (SCAs) are clinically and genetically a heterogeneous group of neurodegenerative disorders. Recently, mild CAG repeat expansion in the alpha1A voltage-dependent calcium channel gene has been found to be associated with a type of autosomal dominant SCA (SCA6). We analyzed 98 Japanese families with autosomal dominant SCAs, for whom CAG repeat expansions of the SCA1, SCA2, Machado-Joseph disease/SCA3, and dentatorubral-pallidoluysian atrophy genes were excluded, and 5 apparently sporadic cases of cortical cerebellar atrophy. The diagnosis of SCA6 was confirmed in 30 families (31%) comprising 47 affected individuals and 1 sporadic case. The size of expanded CAG repeats ranged from 21 to 26 repeat units and was found to be correlated inversely with age at onset. We identified 2 SCA6 patients homozygous for expanded CAG repeats, whose ages at onset were earlier than the 95% lower confidence level, suggesting the presence of a gene dosage effect of expanded CAG repeat. Ataxia is the most common initial symptom found in 45 of the 48 patients. Patients with a prolonged disease course showed other accompanying clinical features including dystonic postures, involuntary movements, and abnormalities in tendon reflexes.