Removing imaging systematics from galaxy clustering measurements with Obiwan: application to the SDSS-IV extended Baryon Oscillation Spectroscopic Survey emission-line galaxy sample

ABSTRACT This work presents the application of a new tool, Obiwan, which uses image simulations to determine the selection function of a galaxy redshift survey and calculate three-dimensional (3D) clustering statistics. Obiwan relies on a forward model of the process by which images of the night sky are transformed into a 3D large-scale structure catalogue, and offers several advantages over more traditional map-based techniques – such as operating on individual exposures and adopting a maximum likelihood approach. The photometric pipeline automatically detects and models galaxies and then generates a catalogue of such galaxies with detailed information for each one of them, including their location, redshift, and so on. Systematic biases in the imaging data are therefore imparted into the catalogues and must be accounted for in any scientific analysis of their information content. Obiwan simulates this process for samples selected from the Legacy Surveys imaging data. This imaging data will be used to select target samples for the next-generation Dark Energy Spectroscopic Instrument (DESI) experiment. Here, we apply Obiwan to a portion of the SDSS-IV extended Baryon Oscillation Spectroscopic Survey emission-line galaxies (ELGs). Systematic biases in the data are clearly identified and removed. We compare the 3D clustering results to those obtained by the map-based approach applied to the complete eBOSS Data Release 16 (DR16) sample. We find the results are consistent, thereby validating the eBOSS DR16 ELG catalogues, which is used to obtain cosmological results.

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The Completed SDSS-IV extended Baryon Oscillation Spectroscopic Survey: measurement of the BAO and growth rate of structure of the emission line galaxy sample from the anisotropic power spectrum between redshift 0.6 and 1.1

Monthly Notices of the Royal Astronomical Society ◽

10.1093/mnras/staa3891 ◽

2020 ◽

Author(s):

Arnaud de Mattia ◽

Vanina Ruhlmann-Kleider ◽

Anand Raichoor ◽

Ashley J Ross ◽

Amélie Tamone ◽

...

Keyword(s):

Growth Rate ◽

Power Spectrum ◽

Emission Line ◽

Large Scale ◽

Sloan Digital Sky Survey ◽

Full Data ◽

Data Set ◽

Weak Preference ◽

Galaxy Sample ◽

Emission Line Galaxies

Abstract We analyse the large-scale clustering in Fourier space of emission line galaxies (ELG) from the Data Release 16 of the Sloan Digital Sky Survey IV extended Baryon Oscillation Spectroscopic Survey. The ELG sample contains 173,736 galaxies covering 1,170 square degrees in the redshift range 0.6 < z < 1.1. We perform a BAO measurement from the post-reconstruction power spectrum monopole, and study redshift space distortions (RSD) in the first three even multipoles. Photometric variations yield fluctuations of both the angular and radial survey selection functions. Those are directly inferred from data, imposing integral constraints which we model consistently. The full data set has only a weak preference for a BAO feature (1.4σ). At the effective redshift zeff = 0.845 we measure $D_{\rm V}(z_{\rm eff})/r_{\rm drag} = 18.33_{-0.62}^{+0.57}$, with DV the volume-averaged distance and rdrag the comoving sound horizon at the drag epoch. In combination with the RSD measurement, at zeff = 0.85 we find $f\sigma _8(z_{\rm eff}) = 0.289_{-0.096}^{+0.085}$, with f the growth rate of structure and σ8 the normalisation of the linear power spectrum, $D_{\rm H}(z_{\rm eff})/r_{\rm drag} = 20.0_{-2.2}^{+2.4}$ and DM(zeff)/rdrag = 19.17 ± 0.99 with DH and DM the Hubble and comoving angular distances, respectively. These results are in agreement with those obtained in configuration space, thus allowing a consensus measurement of fσ8(zeff) = 0.315 ± 0.095, $D_{\rm H}(z_{\rm eff})/r_{\rm drag} = 19.6_{-2.1}^{+2.2}$ and DM(zeff)/rdrag = 19.5 ± 1.0. This measurement is consistent with a flat ΛCDM model with Planck parameters.

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A 16 deg2 survey of emission-line galaxies at z < 1.6 from HSC-SSP PDR2 and CHORUS

Publications of the Astronomical Society of Japan ◽

10.1093/pasj/psaa076 ◽

2020 ◽

Vol 72 (5) ◽

Author(s):

Masao Hayashi ◽

Rhythm Shimakawa ◽

Masayuki Tanaka ◽

Masato Onodera ◽

Yusei Koyama ◽

...

Keyword(s):

Emission Line ◽

Large Scale ◽

Formation Rate ◽

Imaging Data ◽

Star Forming ◽

Public Data ◽

Wide Range ◽

Comprehensive Survey ◽

Strategic Program ◽

Emission Line Galaxies

Abstract We have conducted a comprehensive survey of emission-line galaxies at z ≲ 1.6 based on narrow-band (NB) imaging data taken with Hyper Suprime-Cam (HSC) on the Subaru telescope. In this paper, we update the catalogs of Hα, [O iii], and [O ii] emission-line galaxies using the data from the second Public Data Release (PDR2) of the Subaru Strategic Program (SSP) of the HSC and Cosmic HydrOgen Reionization Unveiled with Subaru (CHORUS) survey along with the spectroscopic redshifts for 2019 emission-line galaxies selected with the PDR1 data. The wider effective coverage of NB816 and NB921, 16.3 deg2 and 16.9 deg2, respectively, are available in the Deep and UltraDeep layers of HSC-SSP from the PDR2. The CHORUS survey provides us with data with additional three NBs (NB527, NB718, and NB973) in the COSMOS field in the UltraDeep layer (1.37 deg2). The five NB datasets allow us to investigate the star-forming galaxies presenting emission-lines at 14 specific redshifts ranging from z ∼ 1.6 down to z ∼ 0.05. We revisit the distribution of large-scale structures and luminosity functions (LFs) for the emission-line galaxies with the large samples of 75377 emission-line galaxies selected. The redshift revolution of LFs shows that the star formation rate densities (SFRDs) decreases monotonically from z ∼ 1.6, which is consistent with the cosmic SFRD known to-date. Our samples of emission-line galaxies covering a sufficiently large survey volume are useful to investigate the evolution of star-forming galaxies since the cosmic noon in a wide range of environments including galaxy clusters, filaments, and voids.

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The completed SDSS-IV extended Baryon Oscillation Spectroscopic Survey: GLAM-QPM mock galaxy catalogues for the emission line galaxy sample

Monthly Notices of the Royal Astronomical Society ◽

10.1093/mnras/staa2571 ◽

2020 ◽

Vol 498 (4) ◽

pp. 5251-5262 ◽

Cited By ~ 5

Author(s):

Sicheng Lin ◽

Jeremy L Tinker ◽

Anatoly Klypin ◽

Francisco Prada ◽

Michael R Blanton ◽

...

Keyword(s):

Emission Line ◽

Large Scale ◽

Small Scale ◽

Selection Function ◽

Number Density ◽

Acoustic Oscillations ◽

Systematic Analysis ◽

Galaxy Sample ◽

Halo Occupation Distribution ◽

Line Galaxy

ABSTRACT We present 2000 mock galaxy catalogues for the analysis of baryon acoustic oscillations (BAOs) in the Emission Line Galaxy (ELG) sample of the extended Baryon Oscillation Spectroscopic Survey Data Release 16 (eBOSS DR16). Each mock catalogue has a number density of $6.7 \times 10^{-4} h^3 \rm Mpc^{-3}$, covering a redshift range from 0.6 to 1.1. The mocks are calibrated to small-scale eBOSS ELG clustering measurements at scales of $\lesssim 30\, h^{-1}$Mpc. The mock catalogues are generated using a combination of GaLAxy Mocks (GLAM) simulations and the quick particle-mesh (QPM) method. GLAM simulations are used to generate the density field, which is then assigned dark matter haloes using the QPM method. Haloes are populated with galaxies using a halo occupation distribution. The resulting mocks match the survey geometry and selection function of the data, and have slightly higher number density that allows room for systematic analysis. The large-scale clustering of mocks at the BAO scale is consistent with data and we present the correlation matrix of the mocks.

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The completed SDSS-IV extended baryon oscillation spectroscopic survey: growth rate of structure measurement from anisotropic clustering analysis in configuration space between redshift 0.6 and 1.1 for the emission-line galaxy sample

Monthly Notices of the Royal Astronomical Society ◽

10.1093/mnras/staa3050 ◽

2020 ◽

Vol 499 (4) ◽

pp. 5527-5546 ◽

Cited By ~ 6

Author(s):

Amélie Tamone ◽

Anand Raichoor ◽

Cheng Zhao ◽

Arnaud de Mattia ◽

Claudio Gorgoni ◽

...

Keyword(s):

Growth Rate ◽

Correlation Function ◽

Emission Line ◽

Sloan Digital Sky Survey ◽

Linear Growth Rate ◽

Angular Diameter Distance ◽

Consensus Values ◽

Galaxy Sample ◽

Emission Line Galaxies ◽

Anisotropic Clustering

ABSTRACT We present the anisotropic clustering of emission-line galaxies (ELGs) from the Sloan Digital Sky Survey IV (SDSS-IV) extended Baryon Oscillation Spectroscopic Survey (eBOSS) Data Release 16 (DR16). Our sample is composed of 173 736 ELGs covering an area of 1170 deg2 over the redshift range 0.6 ≤ z ≤ 1.1. We use the convolution Lagrangian perturbation theory in addition to the Gaussian streaming redshift space distortions to model the Legendre multipoles of the anisotropic correlation function. We show that the eBOSS ELG correlation function measurement is affected by the contribution of a radial integral constraint that needs to be modelled to avoid biased results. To mitigate the effect from unknown angular systematics, we adopt a modified correlation function estimator that cancels out the angular modes from the clustering. At the effective redshift, zeff = 0.85, including statistical and systematical uncertainties, we measure the linear growth rate of structure fσ8(zeff) = 0.35 ± 0.10, the Hubble distance $D_ H(z_{\rm eff})/r_{\rm drag} = 19.1^{+1.9}_{-2.1}$, and the comoving angular diameter distance DM(zeff)/rdrag = 19.9 ± 1.0. These results are in agreement with the Fourier space analysis, leading to consensus values of: fσ8(zeff) = 0.315 ± 0.095, $D_H(z_{\rm eff})/r_{\rm drag} = 19.6^{+2.2}_{-2.1}$, and DM(zeff)/rdrag = 19.5 ± 1.0, consistent with ΛCDM model predictions with Planck parameters.

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An Emission-Line Galaxy Survey with the UK Schmidt Telescope

Symposium - International Astronomical Union ◽

10.1017/s0074180900154907 ◽

1987 ◽

Vol 121 ◽

pp. 53-55

Author(s):

M. Kalafi ◽

A. Savage ◽

A.R. Good ◽

R.D. Cannon ◽

M.G. Yates

Keyword(s):

Emission Line ◽

Large Scale ◽

Preliminary Investigation ◽

Schmidt Telescope ◽

Large Area ◽

Number Magnitude ◽

Emission Line Galaxies ◽

Galaxy Populations ◽

The Uk ◽

Line Galaxy

The use of objective prisms in conjunction with the large area coverage afforded by Schmidt telescopes provides a very powerful means of detecting large numbers of emission-line galaxies, and allows one to study their large scale distribution. An important question that has yet to be fully addressed is the relationship between the number-magnitude distributions of the normal field galaxy and emission-line galaxy populations. A comparison such as this would effectively probe the evolution with time of these active objects. For example, study of the distant (z = 0.458) cluster of galaxies associated with 3C 295 (Dressler & Gunn 1983) indicates that emission-line objects may have been far more numerous in the past than at present. As a preliminary investigation in advance of a larger project, we report here on a search for emission-line galaxies in four United Kingdom 1.2m Schmidt Telescope (UKST) objective prism fields.

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Prediction of H α and [O iii] emission line galaxy number counts for future galaxy redshift surveys

Monthly Notices of the Royal Astronomical Society ◽

10.1093/mnras/stz2844 ◽

2019 ◽

Vol 490 (3) ◽

pp. 3667-3678 ◽

Cited By ~ 1

Author(s):

Zhongxu Zhai ◽

Andrew Benson ◽

Yun Wang ◽

Gustavo Yepes ◽

Chia-Hsun Chuang

Keyword(s):

Emission Line ◽

Galaxy Formation ◽

Luminosity Function ◽

Large Scale ◽

High Redshift ◽

Flux Ratio ◽

Formation Model ◽

Line Flux ◽

Emission Line Galaxies ◽

Number Counts

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.

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N-body Simulations to Test the Reliability of Two-point Correlation Functions of Galaxies

Highlights of Astronomy ◽

10.1017/s1539299600010108 ◽

1992 ◽

Vol 9 ◽

pp. 703-704

Author(s):

Yasushi Suto

Keyword(s):

Correlation Functions ◽

Large Scale ◽

Sample Volume ◽

Limited Data ◽

Observable Universe ◽

Large N ◽

The Galaxy ◽

Point Correlation ◽

Systematic Biases ◽

Redshift Survey

The shape and amplitude of the galaxy – galaxy correlation functions, ξgg(r), are among the most widely used measures of the large-scale structure in the universe (Totsuji & Kihara 1969). The estimates, however, might be seriously affected by the limited size of the sample volume, or equivalently, the limited number of available galaxies. In fact, while the observable universe extends c/H0 ~ 3000h-1Mpc, most observational works to map the distribution of galaxies so far have been mainly applied to samples within ~ 100h-1Mpc from us. Thus a CfA redshift survey slice, for example, of 8h < α < 17h, 26.5° < δ < 32.5°, and cz ≾ 15000km/sec (de Lapparent et al. 1986, 1988) represents merely ~ 2 x 10-5 of the total volume of the observable universe. This clearly illustrates the importance of examining possible systematic biases and variations in the estimates of two-point correlation functions from instrinsically limited data. We studied such sample-to-sample variations by analysing subsamples extracted from large N-body simulation data.

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Large-Scale Structure of Emission-Line Galaxies atz = 3.1

The Astronomical Journal ◽

10.1086/424935 ◽

2004 ◽

Vol 128 (5) ◽

pp. 2073-2079 ◽

Cited By ~ 143

Author(s):

Tomoki Hayashino ◽

Yuichi Matsuda ◽

Hajime Tamura ◽

Ryosuke Yamauchi ◽

Toru Yamada ◽

...

Keyword(s):

Emission Line ◽

Large Scale ◽

Large Scale Structure ◽

Scale Structure ◽

Emission Line Galaxies

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Properties of Galaxies in Low Density Regions

Symposium - International Astronomical Union ◽

10.1017/s0074180900038985 ◽

1983 ◽

Vol 104 ◽

pp. 207-209

Author(s):

N. Brosch

Keyword(s):

Emission Line ◽

Local Density ◽

Three Dimensional ◽

Average Density ◽

Active Galaxies ◽

Nuclear Activity ◽

Isolated Galaxies ◽

Dimensional Distribution ◽

Mass Profile ◽

Emission Line Galaxies

Isolated galaxies seem to have more nuclear activity and less disk activity than nonisolated objects. This is interpreted as an expression of the mass-profile in their halos.The discovery of voids in the three-dimensional distribution of galaxies has rapidly been followed by claims that in at least one such void some objects, like Markarian and emission-line galaxies, are present. Why are only active galaxies found in these voids? Should we also expect the opposite to be true, namely that active galaxies ought to be found more often in voids, or in regions of the Universe with lower-than-average density? There are indications that this seems to be the case, as Gisler (1978) found that emission-line galaxies, Markarians and possibly Seyferts avoid environments of dense clusters. Differences between “field” and “cluster” populations are probably due more to the enhanced local density of galaxies than to the nature of the overall environment.

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