We present a simple and efficient phenomenological model for the two-dimensional two-point galaxy correlation function that works well over a wide range of scales, from large scales down to scales as ...small as 25 h
−1 Mpc. Our model incorporates non-linear effects and a scale-dependent galaxy bias on small scales, and it allows the redshift-space distortions to be scale and direction dependent. We validate our model using LasDamas mock catalogues and apply it to the Sloan Digital Sky Survey (SDSS) Data Release Seven (DR7) luminous red galaxies (LRGs). Using only the monopole and quadrupole of the correlation function measured from the SDSS DR7 LRGs, we obtain improved measurements H(z)r
s
(z
d
)/c = 0.0433 ± 0.0042, D
A(z)/rs
(zd
) = 6.59 ± 0.46 and f (z)σ8(z) = 0.429 ± 0.089 at z = 0.35, using the scale range 25 < s < 120 h
−1 Mpc. We expect our results and model to be useful in tightening dark energy and gravity constraints from the full analysis of current and future galaxy clustering data.
We further develop the description of redshift-space distortions within the effective field theory of large scale structures. First, we generalize the counterterms to include the effect of baryonic ...physics and primordial non-Gaussianity. Second, we evaluate the IR resummation of the dark matter power spectrum in redshift space. This requires us to identify a controlled approximation that makes the numerical evaluation straightforward and efficient. Third, we compare the predictions of the theory at one loop with the power spectrum from numerical simulations up to ℓ=6. We find that the IR resummation allows us to correctly reproduce the baryon acoustic oscillation peak. The k reach-or, equivalently, the precision for a given k-depends on additional counterterms that need to be matched to simulations. Since the nonlinear scale for the velocity is expected to be longer than the one for the overdensity, we consider a minimal and a nonminimal set of counterterms. The quality of our numerical data makes it hard to firmly establish the performance of the theory at high wave numbers. Within this limitation, we find that the theory at redshift z=0.56 and up to ℓ=2 matches the data at the percent level approximately up to k∼0.13 hMpc−1 or k∼0.18 hMpc−1, depending on the number of counterterms used, with a potentially large improvement over former analytical techniques.
ABSTRACT
We present a method for measuring the Hubble parameter, H(z), and angular diameter distance, DA(z), from the two‐dimensional two‐point correlation function and validate it using LasDamas ...mock galaxy catalogues. Applying our method to the sample of luminous red galaxies from the Sloan Digital Sky Survey Data Release 7, we measure H(z=0.35)≡H(0.35)=82.1−4.9+4.8 km s−1 Mpc −1 and DA(z=0.35)≡DA(0.35)=1048−58+60 Mpc without assuming a dark energy model or a flat universe. We find that the derived measurements of H(0.35) rs(zd)/c and DA(0.35)/rs(zd) where rs(zd) is the sound horizon at the drag epoch are nearly uncorrelated, have tighter constraints and are more robust with respect to possible systematic effects. Our galaxy clustering measurements of {H(0.35)rs(zd)/c,DA(0.35)/rs(zd)}={0.0434±0.0018,6.60±0.26} (with the correlation coefficient r = 0.0604) can be used to combine with cosmic microwave background and any other cosmological data sets to constrain dark energy. Our results represent the first measurements of H(z) and DA(z) (or H(z) rs(zd)/c and DA(0.35)/rs(zd)) from galaxy clustering data. Our work has significant implications for future surveys in establishing the feasibility of measuring both H(z) and DA(z) from galaxy clustering data.
We measure and analyse the bispectrum of the final data release 12 (DR12), galaxy sample provided by the Baryon Oscillation Spectroscopic Survey, splitting by selection algorithm into LOWZ and CMASS ...galaxies. The LOWZ sample contains 361 762 galaxies with an effective redshift of z sub( LOWZ) = 0.32, and the CMASS sample contains 777 202 galaxies with an effective redshift of z sub( CMASS) = 0.57. Combining the power spectrum, measured relative to the line of sight, with the spherically averaged bispectrum, we are able to constrain the product of the growth of structure parameter, f, and the amplitude of dark matter density fluctuations, ..., along with the geometric Alcock-Paczynski parameters, the product of the Hubble constant and the comoving sound horizon at the baryon drag epoch, H(z)r sub( s)(z sub( d)), and the angular distance parameter divided by the sound horizon, D sub( A)(z)/r sub( s)(z sub( d)). After combining pre-reconstruction RSD analyses of the power spectrum monopole, quadrupole and bispectrum monopole with post-reconstruction analysis of the BAO power spectrum monopole and quadrupole, we find f(z sub( LOWZ))...(z sub( LOWZ)) = 0.427 plus or minus 0.056, D sub( A)(z sub( LOWZ))/r sub( s)(z sub( d)) = 6.60 plus or minus 0.13, H(z sub( LOWZ))r sub( s)(z sub( d)) = (11.55 plus or minus 0.38)10 super( 3) km s super( -1) for the LOWZ sample, and f(z sub( CMASS))...(z sub( CMASS)) = 0.426 plus or minus 0.029, D sub( A)(z sub( CMASS))/r sub( s)(z sub( d)) = 9.39 plus or minus 0.10, H(z sub( CMASS))r sub( s)(z sub( d)) = (14.02 plus or minus 0.22)10 super( 3) km s super( -1) for the CMASS sample. We find general agreement with previous Baryon Oscillation Spectroscopic Survey DR11 and DR12 measurements. Combining our data set with Planck15 we perform a null test of General Relativity through the ...-parametrization finding ...=0.733..., which is ~2.7... away from the General Relativity predictions. (ProQuest: ... denotes formulae/symbols omitted.)
We present a new methodology to generate mock halo or galaxy catalogues, which have accurate clustering properties, nearly indistinguishable from full N-body solutions, in terms of the one-point, ...two-point, and three-point statistics. In particular, the agreement is remarkable, within 1 per cent up to k = 0.55 h Mpc... and down to r = 10 h... Mpc, for the power spectrum and two-point correlation function, respectively, while the bispectrum agrees in general within 20 per cent for different scales and shapes. Our approach is based on the Zel'dovich approximation, however, effectively including with the simple prescriptions the missing physical ingredients, and stochastic scale-dependent, non-local, and non-linear biasing contributions. The computing time and memory required to produce one mock is similar to that using the lognormal model. With high accuracy and efficiency, the effective Zel'dovich approximation mocks (EZmocks) provide a reliable and practical method to produce massive mock galaxy catalogues for the analysis of large-scale structure measurements. (ProQuest: ... denotes formulae/symbols omitted.)
We measure and analyse the clustering of the Baryon Oscillation Spectroscopic Survey (BOSS) relative to the line of sight (LOS), for LOWZ and CMASS galaxy samples drawn from the final Data Release ...12. The LOWZ sample contains 361 762 galaxies with an effective redshift of z
lowz = 0.32, and the CMASS sample 777 202 galaxies with an effective redshift of z
cmass = 0.57. From the power spectrum monopole and quadrupole moments around the LOS, we measure the growth of structure parameter f times the amplitude of dark matter density fluctuations σ8 by modelling the redshift-space distortion signal. When the geometrical Alcock–Paczynski effect is also constrained from the same data, we find joint constraints on fσ8, the product of the Hubble constant and the comoving sound horizon at the baryon-drag epoch H(z)r
s(z
d), and the angular distance parameter divided by the sound horizon D
A(z)/r
s(z
d). We find f(z
lowz)σ8(z
lowz) = 0.394 ± 0.062, D
A(z
lowz)/r
s(z
d) = 6.35 ± 0.19, H(z
lowz)r
s(z
d) = (11.41 ± 0.56) 103 km s− 1 for the LOWZ sample, and f(z
cmass)σ8(z
cmass) = 0.444 ± 0.038, D
A(z
cmass)/r
s(z
d) = 9.42 ± 0.15, H(z
cmass)r
s(z
d) = (13.92 ± 0.44) 103 km s− 1 for the CMASS sample. We find general agreement with previous BOSS DR11 measurements. Assuming the Hubble parameter and angular distance parameter are fixed at fiducial Λcold dark matter values, we find f(z
lowz)σ8(z
lowz) = 0.485 ± 0.044 and f(z
cmass)σ8(z
cmass) = 0.436 ± 0.022 for the LOWZ and CMASS samples, respectively.
ABSTRACT
We perform a simulation with Galacticus, a semi-analytical galaxy formation model, to predict the number counts of H α and O iii emitting galaxies. With a state-of-the-art N-body simulation, ...UNIT, we first calibrate Galacticus with the current observation of H α luminosity function. The resulting model coupled with a dust attenuation model, can reproduce the current observations, including the H α luminosity function from HiZELS and number density from WISP. We extrapolate the model prediction to higher redshift and the result is found to be consistent with previous investigations. We then use the same galaxy formation model to predict the number counts for O iii emitting galaxies. The result provides further validation of our galaxy formation model and dust model. We present number counts of H α and O iii emission line galaxies for three different line flux limits: 5 × 10−17erg s−1 cm−2, 1 × 10−16 erg s−1 cm−2 (6.5σ nominal depth for WFIRST GRS), and 2 × 10−16 erg s−1 cm−2 (3.5σ depth of Euclid GRS). At redshift 2 < z < 3, our model predicts that WFIRST can observe hundreds of O iii emission line galaxies per square degree with a line flux limit of 1 × 10−16 erg s−1 cm−2. This will provide accurate measurement of large-scale structure to probe dark energy over a huge cosmic volume to an unprecedented high redshift. Finally, we compare the flux ratio of H α/O iii within the redshift range of 0 < z < 3. Our results show the known trend of increasing H α/O iii flux ratio with H α flux at low redshift, which becomes a weaker trend at higher redshifts.
Abstract
We present the UNIT N-body cosmological simulations project, designed to provide precise predictions for non-linear statistics of the galaxy distribution. We focus on characterizing ...statistics relevant to emission line and luminous red galaxies in the current and upcoming generation of galaxy surveys. We use a suite of precise particle mesh simulations (fastpm) as well as with full N-body calculations with a mass resolution of ${\sim } 1.2\times 10^9\, h^{-1}$M⊙ to investigate the recently suggested technique of Angulo and Pontzen to suppress the variance of cosmological simulations. We study redshift-space distortions, cosmic voids, higher order statistics from z = 2 down to 0. We find that both two- and three-point statistics are unbiased. Over the scales of interest for baryon acoustic oscillations and redshift-space distortions, we find that the variance is greatly reduced in the two-point statistics and in the cross-correlation between haloes and cosmic voids, but is not reduced significantly for the three-point statistics. We demonstrate that the accuracy of the two-point correlation function for a galaxy survey with effective volume of 20 (h−1Gpc)3 is improved by about a factor of 40, indicating that two pairs of simulations with a volume of 1 (h−1Gpc)3 lead to the equivalent variance of ∼150 such simulations. The N-body simulations presented here thus provide an effective survey volume of about seven times the effective survey volume of Dark Energy Spectroscopic Instrument or Euclid. The data from this project, including dark matter fields, halo catalogues, and their clustering statistics, are publicly available.
We investigate the anisotropic clustering of the Baryon Oscillation Spectroscopic Survey (BOSS) Data Release 12 sample, which consists of 1198 006 galaxies in the redshift range 0.2 < z < 0.75 and a ...sky coverage of 10 252 deg2. We analyse this data set in Fourier space, using the power-spectrum multipoles to measure redshift-space distortions simultaneously with the Alcock-Paczynski effect and the baryon acoustic oscillation scale. We include the power-spectrum monopole, quadrupole and hexadecapole in our analysis and compare our measurements with a perturbation-theory-based model, while properly accounting for the survey window function. To evaluate the reliability of our analysis pipeline, we participate in a mock challenge, which results in systematic uncertainties significantly smaller than the statistical uncertainties. While the high-redshift constraint on fs8 at zeff = 0.61 indicates a small (~1.4s) deviation from the prediction of the Planck ...CDM (... cold dark matter) model, the low-redshift constraint is in good agreement with Planck ...CDM. This paper is part of a set that analyses the final galaxy clustering data set from BOSS. The measurements and likelihoods presented here are combined with others in Alam et al. to produce the final cosmological constraints from BOSS. (ProQuest: ... denotes formulae/symbols omitted.)