arXiv subjects

Donald P. Schneider

Publications and source records attributed to Donald P. Schneider.

At least 235 records · Page 13Linked to original sources

arXiv2015

Cosmic Web Reconstruction through Density Ridges: Catalogue

We construct a catalogue for filaments using a novel approach called SCMS (subspace constrained mean shift; Ozertem & Erdogmus 2011; Chen et al. 2015). SCMS is a gradient-based method that detects filaments through density ridges (smooth curves tracing high-density regions). A great advantage of SCMS is its uncertainty measure, which allows an evaluation of the errors for the detected filaments. To detect filaments, we use data from the Sloan Digital Sky Survey, which consist of three galaxy samples: the NYU main galaxy sample (MGS), the LOWZ sample and the CMASS sample. Each of the three dataset covers different redshift regions so that the combined sample allows detection of filaments up to z = 0.7. Our filament catalogue consists of a sequence of two-dimensional filament maps at different redshifts that provide several useful statistics on the evolution cosmic web. To construct the maps, we select spectroscopically confirmed galaxies within 0.050 < z < 0.700 and partition them into 130 bins. For each bin, we ignore the redshift, treating the galaxy observations as a 2-D data and detect filaments using SCMS. The filament catalogue consists of 130 individual 2-D filament maps, and each map comprises points on the detected filaments that describe the filamentary structures at a particular redshift. We also apply our filament catalogue to investigate galaxy luminosity and its relation with distance to filament. Using a volume-limited sample, we find strong evidence (6.1$σ$ - 12.3$σ$) that galaxies close to filaments are generally brighter than those at significant distance from filaments.

astro-ph.CO↗

arXiv2015

Testing General Relativity with Growth rate measurement from Sloan Digital Sky Survey III Baryon Oscillations Spectroscopic Survey galaxies

The measured redshift ($z$) of an astronomical object is a combination of Hubble recession, gravitational redshift and peculiar velocity. The line of sight distance to a galaxy inferred from redshift is affected by the peculiar velocity component of galaxy redshift, which is observed as an anisotropy in the correlation function. This anisotropy allows us to measure the linear growth rate of matter ($fσ_8$). We measure the $fσ_8$ at $z=0.57$ using the CMASS sample from Data Release 11 of Sloan Digital Sky Survey III (SDSS III) Baryon Oscillations Spectroscopic Survey (BOSS). The galaxy sample consists of 690,826 massive galaxies in the redshift range 0.43-0.7 covering 8498 deg$^2$. Here we report the first simultaneous measurement of $fσ_8$ and background cosmological parameters using Convolution Lagrangian Perturbation Theory (CLPT) with Gaussian streaming model (GSRSD). We arrive at a constraint of $fσ_8=0.462\pm0.041$ (9\% accuracy) at effective redshift ($\bar{z}=0.57$) when we include Planck CMB likelihood while marginalizing over all other cosmological parameters. We also measure $bσ_8=1.19\pm0.03$, $H(z=0.57)=89.2\pm3.6$ km s$^{-1}$ Mpc$^{-1}$ and $D_A(z=0.57)=1401\pm23$ Mpc. Our analysis also improves the constraint on $Ω_c h^2=0.1196\pm0.0009$ by a factor of 3 when compared to the Planck only measurement($Ω_c h^2=0.1196 \pm 0.0031$). Our results are consistent with Planck $Λ$CDM-GR prediction and all other CMASS measurements, even though our theoretical models are fairly different. This consistency suggests that measurement of $fσ_8$ from Redshift space distortions at multiple redshifts will be a sensitive probe of the theory of gravity that is largely model independent, allowing us to place model-independent constraints on alternative models of gravity.

astro-ph.CO↗

arXiv2015

Now You See It, Now You Don't: The Disappearing Central Engine of the Quasar J1011+5442

We report the discovery of a new "changing-look" quasar, SDSS J101152.98+544206.4, through repeat spectroscopy from the Time Domain Spectroscopic Survey. This is an addition to a small but growing set of quasars whose blue continua and broad optical emission lines have been observed to decline by a large factor on a time scale of approximately a decade. The 5100 Angstrom monochromatic continuum luminosity of this quasar drops by a factor of > 9.8 in a rest-frame time interval of < 9.7 years, while the broad H-alpha luminosity drops by a factor of 55 in the same amount of time. The width of the broad H-alpha line increases in the dim state such that the black hole mass derived from the appropriate single-epoch scaling relation agrees between the two epochs within a factor of 3. The fluxes of the narrow emission lines do not appear to change between epochs. The light curve obtained by the Catalina Sky Survey suggests that the transition occurs within a rest-frame time interval of approximately 500 days. We examine three possible mechanisms for this transition suggested in the recent literature. An abrupt change in the reddening towards the central engine is disfavored by the substantial difference between the timescale to obscure the central engine and the observed timescale of the transition. A decaying tidal disruption flare is consistent with the decay rate of the light curve but not with the prolonged bright state preceding the decay, nor can this scenario provide the power required by the luminosities of the emission lines. An abrupt drop in the accretion rate onto the supermassive black hole appears to be the most plausible explanation for the rapid dimming.

astro-ph.GA↗

arXiv2015

Cold gas and a Milky Way-type 2175 Å bump in a metal-rich and highly depleted absorption system

We report the detection of a strong Milky Way-type 2175 Å$ $ extinction bump at $z$ = 2.1166 in the quasar spectrum towards SDSS J121143.42+083349.7 from the Sloan Digital Sky Survey (SDSS) Data Release 10. We conduct follow up observations with the Echelle Spectrograph and Imager (ESI) onboard the Keck-II telescope and the Ultraviolet and Visual Echelle Spectrograph (UVES) on the VLT. This 2175 Å$ $ absorber is remarkable in that we simultaneously detect neutral carbon (C I), neutral chlorine (Cl I), and carbon monoxide (CO). It also qualifies as a damped Lyman alpha system. The J1211+0833 absorber is found to be metal-rich and has a dust depletion pattern resembling that of the Milky Way disk clouds. We use the column densities of the C I fine structure states and the C II/C I ratio (under the assumption of ionization equilibrium) to derive the temperature and volume density in the absorbing gas. A Cloudy photoionization model is constructed, which utilizes additional atoms/ions to constrain the physical conditions. The inferred physical conditions are consistent with a canonical cold (T $\sim$ 100 K) neutral medium with a high density ($n$(H I) $\sim$ 100 cm$^{-3}$) and a slightly higher pressure than the local interstellar medium. Given the simultaneous presence of C I, CO, and the 2175 Å$ $ bump, combined with the high metallicity, high dust depletion level and overall low ionization state of the gas, the absorber towards J1211+0833 supports the scenario that the presence of the bump requires an evolved stellar population.

astro-ph.GA↗

arXiv2015

The Stripe 82 Massive Galaxy Project I: Catalog Construction

The Stripe 82 Massive Galaxy Catalog (S82-MGC) is the largest-volume stellar mass-limited sample of galaxies beyond z~1 constructed to date. Spanning 139.4 deg2, the S82-MGC includes a mass-limited sample of 41,770 galaxies with log Mstar > 11.2 to z~0.7, sampling a volume of 0.3 Gpc3, roughly equivalent to the volume of the Sloan Digital Sky Survey-I/II (SDSS-I/II) z < 0.15 MAIN sample. The catalog is built on three pillars of survey data: the SDSS Stripe 82 Coadd photometry which reaches r-band magnitudes of 23.5 AB, YJHK photometry at depths of 20th magnitude (AB) from the UK Infrared Deep Sky Survey (UKIDSS) Large Area Survey, and over 70,000 spectroscopic galaxy redshifts from SDSS-I/II and the Baryon Oscillation Spectroscopic Survey (BOSS). We describe the catalog construction and verification, the production of 9-band matched aperture photometry, tests of existing and newly estimated photometric redshifts required to supplement spectroscopic redshifts for 55% of the log Mstar > 11.2 sample, and geometric masking. We provide near-IR based stellar mass estimates and compare these to previous estimates. All catalog products are made publicly available. The S82-MGC not only addresses previous statistical limitations in high-mass galaxy evolution studies but begins tackling inherent data challenges in the coming era of wide-field imaging surveys.

astro-ph.GA↗

arXiv2015

The Biases of Optical Line-Ratio Selection for Active Galactic Nuclei, and the Intrinsic Relationship between Black Hole Accretion and Galaxy Star Formation

We use 317,000 emission-line galaxies from the Sloan Digital Sky Survey to investigate line-ratio selection of active galactic nuclei (AGNs). In particular, we demonstrate that "star formation dilution" by HII regions causes a significant bias against AGN selection in low-mass, blue, star-forming, disk-dominated galaxies. This bias is responsible for the observed preference of AGNs among high-mass, green, moderately star-forming, bulge-dominated hosts. We account for the bias and simulate the intrinsic population of emission-line AGNs using a physically-motivated Eddington ratio distribution, intrinsic AGN narrow line region line ratios, a luminosity-dependent Lbol/L[OIII] bolometric correction, and the observed Mbh-sigma relation. These simulations indicate that, in massive (log(M*/Msun) > 10) galaxies, AGN accretion is correlated with specific star formation rate but is otherwise uniform with stellar mass. There is some hint of lower black hole occupation in low-mass (log(M*/Msun) < 10) hosts, although our modeling is limited by uncertainties in measuring and interpreting the velocity dispersions of low-mass galaxies. The presence of star formation dilution means that AGNs contribute little to the observed strong optical emission lines (e.g., [OIII] and Ha) in low-mass and star-forming hosts. However the AGN population recovered by our modeling indicates that feedback by typical (low- to moderate-accretion) low-redshift AGNs has nearly uniform efficiency at all stellar masses, star formation rates, and morphologies. Taken together, our characterization of the observational bias and resultant AGN occupation function suggest that AGNs are unlikely to be the dominant source of star formation quenching in galaxies, but instead are fueled by the same gas which drives star formation activity.

astro-ph.GA↗

arXiv2015

The Sloan Digital Sky Survey Reverberation Mapping Project: Post-Starburst Signatures in Quasar Host Galaxies at z < 1

Quasar host galaxies are key for understanding the relation between galaxies and the supermassive black holes (SMBHs) at their centers. We present a study of 191 broad-line quasars and their host galaxies at z < 1, using high signal-to-noise ratio (SNR) spectra produced by the Sloan Digital Sky Survey Reverberation Mapping project. Clear detection of stellar absorption lines allows a reliable decomposition of the observed spectra into nuclear and host components, using spectral models of quasar and stellar radiations as well as emission lines from the interstellar medium. We estimate age, mass (M*), and velocity dispersion (sigma*) of the host stars, the star formation rate (SFR), quasar luminosity, and SMBH mass (Mbh), for each object. The quasars are preferentially hosted by massive galaxies with M* ~ 10^{11} Msun characterized by stellar ages around a billion years, which coincides with the transition phase of normal galaxies from the blue cloud to the red sequence. The host galaxies have relatively low SFRs and fall below the main sequence of star-forming galaxies at similar redshifts. These facts suggest that the hosts have experienced an episode of major star formation sometime in the past billion years, which was subsequently quenched or suppressed. The derived Mbh - sigma* and Mbh - M* relations agree with our past measurements and are consistent with no evolution from the local Universe. The present analysis demonstrates that reliable measurements of stellar properties of quasar host galaxies are possible with high-SNR fiber spectra, which will be acquired in large numbers with future powerful instruments such as the Subaru Prime Focus Spectrograph.

astro-ph.GA↗

arXiv2015

The SDSS-IV extended Baryonic Oscillation Spectroscopic Survey: Luminous Red Galaxy Target Selection

We describe the algorithm used to select the Luminous Red Galaxy (LRG) sample for the extended Baryon Oscillation Spectroscopic Survey (eBOSS) of the Sloan Digital Sky Survey IV (SDSS-IV) using photometric data from both the SDSS and the Wide-Field Infrared Survey Explorer (WISE). LRG targets are required to meet a set of color selection criteria and have z-band and i-band MODEL magnitudes z < 19.95 and 19.9 < i < 21.8, respectively. Our algorithm selects roughly 50 LRG targets per square degree, the great majority of which lie in the redshift range 0.6 < z < 1.0 (median redshift 0.71). We demonstrate that our methods are highly effective at eliminating stellar contamination and lower-redshift galaxies. We perform a number of tests using spectroscopic data from SDSS-III/BOSS to determine the redshift reliability of our target selection and its ability to meet the science requirements of eBOSS. The SDSS spectra are of high enough signal-to-noise ratio that at least 89% of the target sample yields secure redshift measurements. We also present tests of the uniformity and homogeneity of the sample, demonstrating that it should be clean enough for studies of the large-scale structure of the universe at higher redshifts than SDSS-III/BOSS LRGs reached.

astro-ph.CO↗

arXiv2015

The Sloan Digital Sky Survey Reverberation Mapping Project: Ensemble Spectroscopic Variability of Quasar Broad Emission Lines

We explore the variability of quasars in the MgII and Hbeta broad emission lines and UV/optical continuum emission using the Sloan Digital Sky Survey Reverberation Mapping project (SDSS-RM). This is the largest spectroscopic study of quasar variability to date: our study includes 29 spectroscopic epochs from SDSS-RM over $6$ months, containing 357 quasars with MgII and 41 quasars with Hbeta . On longer timescales, the study is also supplemented with two-epoch data from SDSS-I/II. The SDSS-I/II data include an additional $2854$ quasars with MgII and 572 quasars with Hbeta. The MgII emission line is significantly variable ($Δf/f$ 10% on 100-day timescales), a necessary prerequisite for its use for reverberation mapping studies. The data also confirm that continuum variability increases with timescale and decreases with luminosity, and the continuum light curves are consistent with a damped random-walk model on rest-frame timescales of $\gtrsim 5$ days. We compare the emission-line and continuum variability to investigate the structure of the broad-line region. Broad-line variability shows a shallower increase with timescale compared to the continuum emission, demonstrating that the broad-line transfer function is not a $δ$-function. Hbeta is more variable than MgII (roughly by a factor of $1.5$), suggesting different excitation mechanisms, optical depths and/or geometrical configuration for each emission line. The ensemble spectroscopic variability measurements enabled by the SDSS-RM project have important consequences for future studies of reverberation mapping and black hole mass estimation of $1<z<2$ quasars.

astro-ph.GA↗

arXiv2015

Constraint on the time variation of the fine-structure constant with the SDSS-III/BOSS DR12 quasar sample

From the Sloan Digital Sky Survey (SDSS) Data Release 12, which covers the full Baryonic Oscillation Spectroscopic Survey (BOSS) footprint, we investigate the possible variation of the fine-structure constant over cosmological time-scales. We analyse the largest quasar sample considered so far in the literature, which contains 13175 spectra (10363 from SDSS-III/BOSS DR12 + 2812 from SDSS-II DR7) with redshift $z<\,$1. We apply the emission-line method on the [O III] doublet (4960, 5008 A) and obtain $Δα/α= \left(0.9 \pm 1.8\right)\times10^{-5}$ for the relative variation of the fine-structure constant. We also investigate the possible sources of systematics: misidentification of the lines, sky OH lines, H$\,β$ and broad line contamination, Gaussian and Voigt fitting profiles, optimal wavelength range for the Gaussian fits, chosen polynomial order for the continuum spectrum, signal-to-noise ratio and good quality of the fits. The uncertainty of the measurement is dominated by the sky subtraction. The results presented in this work, being systematics limited, have sufficient statistics to constrain robustly the variation of the fine-structure constant in redshift bins ($Δz\approx$ 0.06) over the last 7.9 Gyr. In addition, we study the [Ne III] doublet (3870, 3969 A) present in 462 quasar spectra and discuss the systematic effects on using these emission lines to constrain the fine-structure constant variation. Better constraints on $Δα/α $ ($<$10$^{-6}$) using the emission-line method would be possible with high-resolution spectroscopy and large galaxy/qso surveys.

astro-ph.CO↗

arXiv2015

The BOSS-WiggleZ overlap region I: Baryon Acoustic Oscillations

We study the large-scale clustering of galaxies in the overlap region of the Baryon Oscillation Spectroscopic Survey (BOSS) CMASS sample and the WiggleZ Dark Energy Survey. We calculate the auto-correlation and cross-correlation functions in the overlap region of the two datasets and detect a Baryon Acoustic Oscillation (BAO) signal in each of them. The BAO measurement from the cross-correlation function represents the first such detection between two different galaxy surveys. After applying density-field reconstruction we report distance-scale measurements $D_V r_s^{\rm fid} / r_s = (1970 \pm 47, 2132 \pm 67, 2100 \pm 200)$ Mpc from CMASS, the cross-correlation and WiggleZ, respectively. We use correlated mock realizations to calculate the covariance between the three BAO constraints. The distance scales derived from the two datasets are consistent, and are also robust against switching the displacement fields used for reconstruction between the two surveys. This approach can be used to construct a correlation matrix, permitting for the first time a rigorous combination of WiggleZ and CMASS BAO measurements. Using a volume-scaling technique, our result can also be used to combine WiggleZ and future CMASS DR12 results. Finally, we use the cross-correlation function measurements to show that the relative velocity effect, a possible source of systematic uncertainty for the BAO technique, is consistent with zero for our samples.

astro-ph.CO↗

arXiv2015

Clustering of intermediate redshift quasars using the final SDSS III-BOSS sample

We measure the two-point clustering of spectroscopically confirmed quasars from the final sample of the Baryon Oscillation Spectroscopic Survey (BOSS) on comoving scales of 4 < s < 22 Mpc/h. The sample covers 6950 deg^2 (~ 19 (Gpc/h)^3) and, over the redshift range 2.2 < z < 2.8, contains 55,826 homogeneously selected quasars, which is twice as many as in any similar work. We deduce b_Q = 3.54 +/- 0.10 ; the most precise measurement of quasar bias to date at these redshifts. This corresponds to a host halo mass of ~ 2 x 10^12 ~ M_sun/h with an implied quasar duty cycle of ~1 percent. The real-space projected correlation function is well-fit by a power law of index -2 and correlation length r0 = (8.12 +/- 0.22), Mpc/h over scales of 4 < rp < 25 ~ Mpc/h. To better study the evolution of quasar clustering at moderate redshift, we extend the redshift range of our study to z ~ 3.4 and measure the bias and correlation length of three subsamples over 2.2 < z < 3.4. We find no significant evolution of r0 or bias over this range, implying that the host halo mass of quasars decreases somewhat with increasing redshift. We find quasar clustering remains similar over a decade in luminosity, contradicting a scenario in which quasar luminosity is monotonically related to halo mass at z ~ 2.5. Our results are broadly consistent with previous BOSS measurements, but they yield more precise constraints based upon a larger and more uniform data set.

astro-ph.CO↗

arXiv2015

Near-ultraviolet Spectroscopy of Star-forming Galaxies from eBOSS: Signatures of Ubiquitous Galactic-scale Outflows

We present the rest-frame near-ultraviolet (NUV) spectroscopy of star-forming galaxies (SFGs) at 0.6 0.6. We use the data from the pilot observations of this program, including 8620 spectra of SFGs at 0.6<z<1.2. The median composite spectra of these SFGs at 2200 Ang < λ< 4000 Ang feature asymmetric, preferentially blueshifted non-resonant emission, Fe II*, and blueshifted resonant absorption, e.g., Fe II and Mg II, indicating ubiquitous outflows driven by star formation at these redshifts. For the absorption lines, we find a variety of velocity profiles with different degrees of blueshift. Comparing our new observations with the literature, we do not observe the non-resonant emission in the small-aperture (<40 pc) spectra of local star-forming regions with the Hubble Space Telescope, and find the observed line ratios in the SFG spectra to be different from those in the spectra of local star-forming regions, as well as those of quasar absorption-line systems in the same redshift range. We introduce an outflow model that can simultaneously explain the multiple observed properties and suggest that the variety of absorption velocity profiles and the line ratio differences are caused by scattered fluorescent emission filling in on top of the absorption in the large-aperture eBOSS spectra. We develop an observation-driven, model-independent method to correct the emission-infill to reveal the true absorption profiles. Our results show that eBOSS and future dark-energy surveys (e.g., DESI and PFS) will provide rich datasets of NUV spectroscopy for astrophysical applications.

astro-ph.GA↗

arXiv2015

The Stripe 82 Massive Galaxy Project II: Stellar Mass Completeness of Spectroscopic Galaxy Samples from the Baryon Oscillation Spectroscopic Survey

The Baryon Oscillation Spectroscopic Survey (BOSS) has collected spectra for over one million galaxies at $0.15 11.6$ only in the narrow redshift range $z=[0.51,0.61]$. The low redshift LOWZ sample is 80% complete at $\log_{10}(M_*/M_{\odot}) >11.6$ for $z=[0.15,0.43]$. To construct mass complete samples at lower masses, spectroscopic samples need to be significantly supplemented by photometric redshifts. This work will enable future studies to better utilize the BOSS samples for galaxy-formation science.

astro-ph.GA↗

arXiv2015

Probing Galactic Structure with the Spatial Correlation Function of SEGUE G-dwarf Stars

We measure the two-point correlation function of G-dwarf stars within 1-3 kpc of the Sun in multiple lines-of-sight using the Schlesinger et al. G-dwarf sample from the SDSS SEGUE survey. The shapes of the correlation functions along individual SEGUE lines-of-sight depend sensitively on both the stellar-density gradients and the survey geometry. We fit smooth disk galaxy models to our SEGUE clustering measurements, and obtain strong constraints on the thin- and thick-disk components of the Milky Way. Specifically, we constrain the values of the thin- and thick-disk scale heights with 3% and 2% precision, respectively, and the values of the thin- and thick-disk scale lengths with 20% and 8% precision, respectively. Moreover, we find that a two-disk model is unable to fully explain our clustering measurements, which exhibit an excess of clustering at small scales (< 50 pc). This suggests the presence of small-scale substructure in the disk system of the Milky Way.

astro-ph.GA↗

arXiv2015

The power spectrum and bispectrum of SDSS DR11 BOSS galaxies II: cosmological interpretation

We examine the cosmological implications of the measurements of the linear growth rate of cosmological structure obtained in a companion paper from the power spectrum and bispectrum monopoles of the Sloan Digital Sky Survey III Baryon Oscillation Spectroscopic Survey Data, Release 11, CMASS galaxies. This measurement was of $f^{0.43}σ_8$, where $σ_8$ is the amplitude of dark matter density fluctuations, and $f$ is the linear growth rate, at the effective redshift of the survey, $z_{\rm eff}=0.57$. In conjunction with Cosmic Microwave Background (CMB) data, interesting constraints can be placed on models with non-standard neutrino properties and models where gravity deviates from general relativity on cosmological scales. In particular, the sum of the masses of the three species of the neutrinos is constrained to $m_ν<0.49\,{\rm eV}$ (at 95\% confidence level) when the $f^{0.43}σ_8$ measurement is combined with state-of-the-art CMB measurements. Allowing the effective number of neutrinos to vary as a free parameter does not significantly change these results. When we combine the measurement of $f^{0.43}σ_8$ with the complementary measurement of $fσ_8$ from the monopole and quadrupole of the two-point correlation function we are able to obtain an independent measurements of $f$ and $σ_8$. We obtain $f=0.63\pm0.16$ and $σ_8=0.710\pm0.086$ (68\% confidence level). This is the first time when these parameters have been able to be measured independently using the redshift-space power spectrum and bispectrum measurements from galaxy clustering data only.

astro-ph.CO↗

arXiv2015

Improved Spectrophotometric Calibration of the SDSS-III BOSS Quasar Sample

We present a model for spectrophotometric calibration errors in observations of quasars from the third generation of the Sloan Digital Sky Survey (SDSS-III) Baryon Oscillation Spectroscopic Survey (BOSS) and describe the correction procedure we have developed and applied to this sample. Calibration errors are primarily due to atmospheric differential refraction and guiding offsets during each exposure. The corrections potentially reduce the systematics for any studies of BOSS quasars, including the measurement of baryon acoustic oscillations using the Lyman-$α$ forest. Our model suggests that, on average, the observed quasar flux in BOSS is overestimated by $\sim 19\%$ at 3600 Å and underestimated by $\sim 24\%$ at 10,000 Å. Our corrections for the entire BOSS quasar sample are publicly available.

astro-ph.IM↗

arXiv2015

The BOSS-WiggleZ overlap region II: dependence of cosmic growth on galaxy type

The anisotropic galaxy 2-point correlation function (2PCF) allows measurement of the growth of large-scale structures from the effect of peculiar velocities on the clustering pattern. We present new measurements of the auto- and cross- correlation function multipoles of 69,180 WiggleZ and 46,380 BOSS-CMASS galaxies sharing an overlapping volume of ~0.2 (Gpc/h)^3. Analysing the redshift-space distortions (RSD) of galaxy 2-point statistics for these two galaxy tracers, we test for systematic errors in the modelling depending on galaxy type and investigate potential improvements in cosmological constraints. We build a large number of mock galaxy catalogues to examine the limits of different RSD models in terms of fitting scales and galaxy type, and to study the covariance of the measurements when performing joint fits. For the galaxy data, fitting the monopole and quadrupole of the WiggleZ 2PCF on scales 24<s<80 Mpc/h produces a measurement of the normalised growth rate $fσ_8$(z=0.54)=0.409$\pm$0.059, whereas for the CMASS galaxies we found a consistent constraint of $fσ_8$(z=0.54)=0.466$\pm$0.074. When combining the measurements, accounting for the correlation between the two surveys, we obtain $fσ_8$(z=0.54)=0.413$\pm$0.054, in agreement with the LCDM-GR model of structure growth and with other survey measurements.

astro-ph.CO↗