We present distance scale measurements from the baryon acoustic oscillation signal in the constant stellar mass and low-redshift sample samples from the Data Release 12 of the Baryon Oscillation ...Spectroscopic Survey. The total volume probed is 14.5 Gpc3, a 10 per cent increment from Data Release 11. From an analysis of the spherically averaged correlation function, we infer a distance to z = 0.57 of
$D_V(z)r^{\rm fid}_{\rm d}/r_{\rm d} = 2028\pm 21$
Mpc and a distance to z = 0.32 of
$D_V(z)r^{\rm fid}_{\rm d}/r_{\rm d} = 1264\pm 22$
Mpc assuming a cosmology in which
$r^{\rm fid}_{\rm d} = 147.10$
Mpc. From the anisotropic analysis, we find an angular diameter distance to z = 0.57 of
$D_{\rm A}(z)r^{\rm fid}_{\rm d}/r_{\rm d} = 1401\pm 21$
Mpc and a distance to z = 0.32 of 981 ± 20 Mpc, a 1.5 and 2.0 per cent measurement, respectively. The Hubble parameter at z = 0.57 is
$H(z)r_{\rm d}/r^{\rm fid}_{\rm d} = 100.3\pm 3.7$
km s−1 Mpc−1 and its value at z = 0.32 is 79.2 ± 5.6 km s−1 Mpc−1, a 3.7 and 7.1 per cent measurement, respectively. These cosmic distance scale constraints are in excellent agreement with a Λ cold dark matter model with cosmological parameters released by the recent Planck 2015 results.
We present an algorithm to photometrically calibrate wide-field optical imaging surveys, which simultaneously solves for the calibration parameters and relative stellar fluxes using overlapping ...observations. The algorithm decouples the problem of "relative" calibrations from that of "absolute" calibrations; the absolute calibration is reduced to determining a few numbers for the entire survey. We pay special attention to the spatial structure of the calibration errors, allowing one to isolate particular error modes in downstream analyses. Applying this to the SDSS imaging data, we achieve similar to 1% relative calibration errors across 8500 deg super(2) in griz; the errors are similar to 2% for the u band. These errors are dominated by unmodeled atmospheric variations at Apache Point Observatory. These calibrations, dubbed "ubercalibration," are now public with SDSS Data Release 6 and will be a part of subsequent SDSS data releases.
We describe the automated spectral classification, redshift determination, and parameter measurement pipeline in use for the Baryon Oscillation Spectroscopic Survey (BOSS) of the Sloan Digital Sky ...Survey UI (SDSS-III) as of the survey's ninth data release (DR9), encompassing 831,000 moderate-resolution optical spectra. We give a review of the algorithms employed, and describe the changes to the pipeline that have been implemented for BOSS relative to previous SDSS-I/II versions, including new sets of stellar, galaxy, and quasar redshift templates. We test the accuracy of these statistical redshift error estimates using repeat observations, finding them underestimated by a factor of 1.19-1.34 for galaxies and by a factor of two for quasars. We assess the impact of sky-subtraction quality, signal-to-noise ratio, and other factors on galaxy redshift success. Finally, we document known issues with the BOSS DR9 spectroscopic data set and describe directions of ongoing development
The spectroscopic Sloan Digital Sky Survey (SDSS) Data Release 7 (DR7) galaxy sample represents the final set of galaxies observed using the original SDSS target selection criteria. We analyse the ...clustering of galaxies within this sample, including both the luminous red galaxy and main samples, and also include the 2-degree Field Galaxy Redshift Survey data. In total, this sample comprises 893 319 galaxies over 9100 deg2. Baryon acoustic oscillations (BAO) are observed in power spectra measured for different slices in redshift; this allows us to constrain the distance–redshift relation at multiple epochs. We achieve a distance measure at redshift z= 0.275, of rs(zd)/DV(0.275) = 0.1390 ± 0.0037 (2.7 per cent accuracy), where rs(zd) is the comoving sound horizon at the baryon-drag epoch, DV(z) ≡(1 +z)2D2Acz/H(z)1/3, DA(z) is the angular diameter distance and H(z) is the Hubble parameter. We find an almost independent constraint on the ratio of distances DV(0.35)/DV(0.2) = 1.736 ± 0.065, which is consistent at the 1.1σ level with the best-fitting Λ cold dark matter model obtained when combining our z= 0.275 distance constraint with the Wilkinson Microwave Anisotropy Probe 5-year (WMAP5) data. The offset is similar to that found in previous analyses of the SDSS DR5 sample, but the discrepancy is now of lower significance, a change caused by a revised error analysis and a change in the methodology adopted, as well as the addition of more data. Using WMAP5 constraints on Ωbh2 and Ωc h2, and combining our BAO distance measurements with those from the Union supernova sample, places a tight constraint on Ωm= 0.286 ± 0.018 and H0= 68.2 ± 2.2 km s−1 Mpc−1 that is robust to allowing Ωk≠ 0 and w≠−1. This result is independent of the behaviour of dark energy at redshifts greater than those probed by the BAO and supernova measurements. Combining these data sets with the full WMAP5 likelihood constraints provides tight constraints on both Ωk=−0.006 ± 0.008 and w=−0.97 ± 0.10 for a constant dark energy equation of state.
With the largest spectroscopic galaxy survey volume drawn from the SDSS-III Baryon Oscillation Spectroscopic Survey (BOSS), we can extract cosmological constraints from the measurements of redshift ...and geometric distortions at quasi-linear scales (e.g. above 50 h
−1 Mpc). We analyse the broad-range shape of the monopole and quadrupole correlation functions of the BOSS Data Release 12 (DR12) CMASS galaxy sample, at the effective redshift z = 0.59, to obtain constraints on the Hubble expansion rate H(z), the angular- diameter distance D
A
(z), the normalized growth rate f(z)σ8(z), and the physical matter density Ωm h
2. We obtain robust measurements by including a polynomial as the model for the systematic errors, and find it works very well against the systematic effects, e.g. ones induced by stars and seeing. We provide accurate measurements {D
A
(0.59)r
s,fid/r
s
, H(0.59)r
s
/r
s,fid, f(0.59)σ8(0.59), Ωm h
2} = {1427 ± 26 Mpc, 97.3 ± 3.3 km s−1 Mpc−1, 0.488 ± 0.060, 0.135 ± 0.016}, where r
s
is the comoving sound horizon at the drag epoch and r
s,fid = 147.66 Mpc is the sound scale of the fiducial cosmology used in this study. The parameters which are not well constrained by our galaxy clustering analysis are marginalized over with wide flat priors. Since no priors from other data sets, e.g. cosmic microwave background (CMB), are adopted and no dark energy models are assumed, our results from BOSS CMASS galaxy clustering alone may be combined with other data sets, i.e. CMB, SNe, lensing or other galaxy clustering data to constrain the parameters of a given cosmological model. The uncertainty on the dark energy equation of state parameter, w, from CMB+CMASS is about 8 per cent. The uncertainty on the curvature fraction, Ω
k
, is 0.3 per cent. We do not find deviation from flat ΛCDM.
We use the observed anisotropic clustering of galaxies in the Baryon Oscillation Spectroscopic Survey Data Release 11 CMASS sample to measure the linear growth rate of structure, the Hubble expansion ...rate and the comoving distance scale. Our sample covers 8498 deg2 and encloses an effective volume of 6 Gpc3 at an effective redshift of
. We find fσ8 = 0.441 ± 0.044, H = 93.1 ± 3.0 km s−1 Mpc−1 and D
A = 1380 ± 23 Mpc when fitting the growth and expansion rate simultaneously. When we fix the background expansion to the one predicted by spatially flat Λ cold dark matter (ΛCDM) model in agreement with recent Planck
results, we find fσ8 = 0.447 ± 0.028 (6 per cent accuracy). While our measurements are generally consistent with the predictions of ΛCDM and general relativity, they mildly favour models in which the strength of gravitational interactions is weaker than what is predicted by general relativity. Combining our measurements with recent cosmic microwave background data results in tight constraints on basic cosmological parameters and deviations from the standard cosmological model. Separately varying these parameters, we find w = −0.983 ± 0.075 (8 per cent accuracy) and γ = 0.69 ± 0.11 (16 per cent accuracy) for the effective equation of state of dark energy and the growth rate index, respectively. Both constraints are in good agreement with the standard model values of w = −1 and γ = 0.554.
ABSTRACT We present a recalibration of the Sloan Digital Sky Survey (SDSS) photometry with new flat fields and zero points derived from Pan-STARRS1. Using point-spread function (PSF) photometry of 60 ...million stars with 16 < r < 20, we derive a model of amplifier gain and flat-field corrections with per-run rms residuals of 3 millimagnitudes (mmag) in griz bands and 15 mmag in u band. The new photometric zero points are adjusted to leave the median in the Galactic north unchanged for compatibility with previous SDSS work. We also identify transient non-photometric periods in SDSS ("contrails") based on photometric deviations co-temporal in SDSS bands. The recalibrated stellar PSF photometry of SDSS and PS1 has an rms difference of {9, 7, 7, 8} mmag in griz, respectively, when averaged over 15′ regions.
We present the power spectrum of the reconstructed halo density field derived from a sample of luminous red galaxies (LRGs) from the Sloan Digital Sky Survey (SDSS) Seventh Data Release (DR7). The ...halo power spectrum has a direct connection to the underlying dark matter power for k≤ 0.2 h Mpc−1, well into the quasi-linear regime. This enables us to use a factor of ∼8 more modes in the cosmological analysis than an analysis with kmax= 0.1 h Mpc−1, as was adopted in the SDSS team analysis of the DR4 LRG sample. The observed halo power spectrum for 0.02 < k < 0.2 h Mpc−1 is well fitted by our model: χ2= 39.6 for 40 degrees of freedom for the best-fitting Λ cold dark matter (ΛCDM) model. We find Ωmh2(ns/0.96)1.2= 0.141+0.010−0.012 for a power-law primordial power spectrum with spectral index ns and Ωbh2= 0.022 65 fixed, consistent with cosmic microwave background measurements. The halo power spectrum also constrains the ratio of the comoving sound horizon at the baryon-drag epoch to an effective distance to z= 0.35: rs/DV(0.35) = 0.1097+0.0039−0.0042. Combining the halo power spectrum measurement with the Wilkinson Microwave Anisotropy Probe (WMAP) 5 year results, for the flat ΛCDM model we find Ωm= 0.289 ± 0.019 and H0= 69.4 ± 1.6 km s−1 Mpc−1. Allowing for massive neutrinos in ΛCDM, we find eV at the 95 per cent confidence level. If we instead consider the effective number of relativistic species Neff as a free parameter, we find Neff= 4.8+1.8−1.7. Combining also with the Kowalski et al. supernova sample, we find Ωtot= 1.011 ± 0.009 and w=−0.99 ± 0.11 for an open cosmology with constant dark energy equation of state w. The power spectrum and a module to calculate the likelihoods are publicly available at http://lambda.gsfc.nasa.gov/toolbox/lrgdr/.
We examine a sample of low-redshift (10 h super(-1) Mpc < d< 150 h super(-1) Mpc) field galaxies including galaxies with luminosities as low as M sub(r) - 5 log h 6 -12.5, selected from the Sloan ...Digital Sky Survey Data Release 2 (SDSS DR2). The sample is unique in containing galaxies of extremely low luminosities in a wide range of environments, selected with uniform and well-understood criteria. We present the luminosity function, as well as the broadband properties, of low-luminosity galaxies in this sample. A Schechter function is an insufficient parameterization of the r-band luminosity function; there is an upturn in the slope for M sub(r) - 5 log h > -18. The resulting slope at low luminosities in this sample is a sub(2) 6 -1.3. However, we almost certainly miss a large number of galaxies at very low luminosities due to low surface brightness selection effects, and we estimate that the true low-luminosity slope may be as steep as or steeper than a sub(2) 6 -1.5. The results here are consistent with previous SDSS results and, in the g band, roughly consistent with the results of the Two Degree Field Galaxy Redshift Survey. Extremely low luminosity galaxies are predominantly low surface brightness, exponential disks, the majority of which are red.
Abstract
We conducted a deep spectroscopic survey, named SSA22-HIT, in the SSA22 field with the DEep Imaging MultiObject Spectrograph (DEIMOS) on the Keck telescope, designed to tomographically map ...high-
z
H
i
gas through analysis of Ly
α
absorption in background galaxies’ spectra. In total, 198 galaxies were spectroscopically confirmed at 2.5 <
z
< 6 with a few low-
z
exceptions in the 26 × 15 arcmin
2
area, of which 148 were newly determined in this study. Our redshift measurements were merged with previously confirmed redshifts available in the 34 × 27 arcmin
2
area of the SSA22 field. This compiled catalog containing 730 galaxies of various types at
z
> 2 is useful for various applications, and it is made publicly available. Our SSA22-HIT survey has increased by approximately twice the number of spectroscopic redshifts of sources at
z
> 3.2 in the observed field. From a comparison with publicly available redshift catalogs, we show that our compiled redshift catalog in the SSA22 field is comparable to those among major extragalactic survey fields in terms of a combination of wide area and high surface number density of objects at
z
> 2. About 40% of the spectroscopically confirmed objects in SSA22-HIT show reasonable quality of spectra in the wavelengths shorter than Ly
α
when a sufficient amount of smoothing is adopted. Our data set enables us to make the H
i
tomographic map at
z
≳ 3, which we present in a parallel study.
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