We have created a variety of composite quasar spectra using a homogeneous data set of over 2200 spectra from the Sloan Digital Sky Survey (SDSS). The quasar sample spans a redshift range of 0.044 ¹ z ¹ 4.789 and an absolute r@ magnitude range of [18.0 to [26.5. The input spectra cover an observed wavelength range of 3800È9200 at a resolution of 1800. The median composite covers a rest-A wavelength range from 800 to 8555 and reaches a peak signal-to-noise ratio of over 300 per 1 A A resolution element in the rest frame. We have identiÐed over 80 emission-line features in the spectrum. Emission-line shifts relative to nominal laboratory wavelengths are seen for many of the ionic species. Peak shifts of the broad permitted and semiforbidden lines are strongly correlated with ionization energy, as previously suggested, but we Ðnd that the narrow forbidden lines are also shifted by amounts that are strongly correlated with ionization energy. The magnitude of the forbidden line shifts is [100 km s~1, compared with shifts of up to 550 km s~1 for some of the permitted and semiforbidden lines. At wavelengths longer than the Lya emission, the continuum of the geometric mean composite is well Ðtted by two power laws, with a break at B5000 The frequency power-law index, is [0.44 from B1300 A. a l , to 5000 and [2.45 redward of B5000 The abrupt change in slope can be accounted for partly by A A. host-galaxy contamination at low redshift. Stellar absorption lines, including higher order Balmer lines, seen in the composites suggest that young or intermediate-age stars make a signiÐcant contribution to the light of the host galaxies. Most of the spectrum is populated by blended emission lines, especially in the range 1500È3500 which can make the estimation of quasar continua highly uncertain unless large A , ranges in wavelength are observed. An electronic table of the median quasar template is available.

We present the first measurements of clustering in the Sloan Digital Sky Survey (SDSS) galaxy redshift survey. Our sample consists of 29,300 galaxies with redshifts 5700 km s À1 cz 39; 000 km s À1 , distributed in several long but narrow (2=5-5) segments, covering 690 deg 2. For the full, flux-limited sample, the redshiftspace correlation length is approximately 8 h À1 Mpc. The two-dimensional correlation function ðr p ; Þ shows clear signatures of both the small-scale, '' fingers-of-God '' distortion caused by velocity dispersions in collapsed objects and the large-scale compression caused by coherent flows, though the latter cannot be measured with high precision in the present sample. The inferred real-space correlation function is well described by a power law, ðrÞ ¼ ðr=6:1 AE 0:2 h À1 MpcÞ À1:75AE0:03 , for 0:1 h À1 Mpc r 16 h À1 Mpc. The galaxy pairwise velocity dispersion is 12 % 600 AE 100 km s À1 for projected separations 0:15 h À1 Mpc r p 5 h À1 Mpc. When we divide the sample by color, the red galaxies exhibit a stronger and steeper real-space correlation function and a higher pairwise velocity dispersion than do the blue galaxies. The relative behavior of subsamples defined by high/low profile concentration or high/low surface brightness is qualitatively similar to that of the red/blue subsamples. Our most striking result is a clear measurement of scale-independent luminosity bias at rd10 h À1 Mpc: subsamples with absolute magnitude ranges centered on M Ã À 1:5, M Ã , and M Ã þ 1:5 have real-space correlation functions that are parallel power laws of slope %À1.8 with correlation lengths of approximately 7.4, 6.3, and 4.7 h À1 Mpc, respectively.

In this paper, we present results from the complete set of cosmic microwave background (CMB) radiation temperature anisotropy observations made with the Arcminute Cosmology Bolometer Array Receiver (ACBAR) operating at 150 GHz. We include new data from the final 2005 observing season, expanding the number of detector-hours by 210% and the sky coverage by 490% over that used for the previous ACBAR release. As a result, the band-power uncertainties have been reduced by more than a factor of two on angular scales encompassing the third to fifth acoustic peaks as well as the damping tail of the CMB power spectrum. The calibration uncertainty has been reduced from 6% to 2.1% in temperature through a direct comparison of the CMB anisotropy measured by ACBAR with that of the dipole-calibrated WMAP5 experiment. The measured power spectrum is consistent with a spatially flat, ΛCDM cosmological model. We include the effects of weak lensing in the power spectrum model computations and find that this significantly improves the fits of the models to the combined ACBAR+WMAP5 power spectrum. The preferred strength of the lensing is consistent with theoretical expectations. On fine angular scales, there is weak evidence (1.1σ) for excess power above the level expected from primary anisotropies. We expect any excess power to be dominated by the combination of emission from dusty protogalaxies and the Sunyaev-Zel'dovich effect (SZE). However, the excess observed by ACBAR is significantly smaller than the excess power at ℓ > 2000 reported by the CBI experiment operating at 30 GHz. Therefore, while it is unlikely that the CBI excess has a primordial origin; the combined ACBAR and CBI results are consistent with the source of the CBI excess being either the SZE or radio source contamination.

During commissioning observations, the Sloan Digital Sky Survey (SDSS) has produced one of the largest existing galaxy redshift samples selected from CCD images. Using 11,275 galaxies complete to r^* = 17.6 over 140 square degrees, we compute the luminosity function of galaxies in the r^* band over a range -23 < M < -16 (for h=1). The result is well-described by a Schechter function with parameters phi_* = 0.0146 +/- 0.0012 h^3 Mpc^{-3}, M_* = -20.83 +/- 0.03, and alpha = -1.20 +/- 0.03. The implied luminosity density in r^* is j = (2.6 +/- 0.3) x 10^8 h L_sun Mpc^{-3}. The surface brightness selection threshold has a negligible impact for M < -18. We measure the luminosity function in the u^*, g^*, i^*, and z^* bands as well; the slope at low luminosities ranges from alpha=-1.35 to alpha=-1.2. We measure the bivariate distribution of r^* luminosity with half-light surface brightness, intrinsic color, and morphology. High surface brightness, red, highly concentrated galaxies are on average more luminous than low surface brightness, blue, less concentrated galaxies. If we synthesize results for R-band or b_j-band using the Petrosian magnitudes with which the SDSS measures galaxy fluxes, we obtain luminosity densities 2.0 times that found by the Las Campanas Redshift Survey in R and 1.4 times that found by the Two-degree Field Galaxy Redshift Survey in b_j. We are able to reproduce the luminosity functions obtained by these surveys if we also mimic their isophotal limits for defining galaxy magnitudes, which are shallower and more redshift dependent than the Petrosian magnitudes used by the SDSS. (Abridged)Comment: 49 pages, including 23 figures, accepted by AJ; some minor textual changes, plus an important change in comparison to LCR