The Subaru FMOS galaxy redshift survey (FastSound). V. Intrinsic alignments of emission-line galaxies at z ∼ 1.4

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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FLAIR II Spectroscopy of Two DENIS J Band Galaxy Samples

Publications of the Astronomical Society of Australia ◽

10.1071/as01041 ◽

2001 ◽

Vol 18 (3) ◽

pp. 232-242 ◽

Cited By ~ 6

Author(s):

Gary A. Mamon ◽

Quentin A. Parker ◽

Dominique Proust

Keyword(s):

Uv Light ◽

Emission Lines ◽

Galactic Latitude ◽

Low Latitude ◽

High Galactic Latitude ◽

Cluster Of Galaxies ◽

Redshift Survey ◽

Galaxy Redshift ◽

Emission Line Galaxies ◽

Optical Surveys

AbstractAs a pilot survey for the forthcoming 6dF Galaxy Redshift Survey, spectroscopy of galaxies selected in the 1.2 micron J waveband with the DENIS imaging survey was performed at the UKST using the FLAIR II multi-object spectroscope. Sixty-nine galaxy redshifts were obtained in a high galactic latitude field and an additional 12 redshifts in a low galactic latitude (b = 17˚), obscured field. This spectroscopic followup of NIR selected galaxies illustrates the feasibility of obtaining redshifts with optical spectra on galaxies selected at much longer wavelengths. It validated a very preliminary algorithm for star/galaxy separation for high galactic latitude DENIS objects, with 99% reliability for J <13.9. The FLAIR II redshifts are in excellent agreement with those, previously published, of 20 common galaxies. However, the FLAIR II redshift determinations presented here required substantially longer integration times to achieve 90% completeness than expected from previous optical surveys at comparable depth. This is mainly due to a degradation in overall fibre throughput due to known problems with ageing of the prism–cement–fibre interface with exposure to UV light. In comparison to our high galactic latitude field, our low latitude (high extinction) field required 2.5 times more exposure time for less than 50% of successful redshift measurements.Among the J ≤ 13.9 galaxies with measured redshifts, only 376% display emission lines, in comparison with 60% of emission line galaxies in optical samples of comparable depth. These galaxies are, on average, half a magnitude bluer in B-J than galaxies of the same luminosity without emission lines. We confirm a previous optically-based result that the fraction of galaxies with emission lines increases rapidly with decreasing galaxy luminosity. The J band luminosity function is estimated. Our high latitude field displays a concentration of galaxies at cz ≲ 38 000 km s−1 suggesting a possible supercluster.A radial velocity is reported for a galaxy lying near the projected centre of the Abell 1434 cluster of galaxies, for which no cluster redshift is currently available.

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Kiss: A New Digital Survey for Emission-Line Objects

Symposium - International Astronomical Union ◽

10.1017/s0074180900128852 ◽

1998 ◽

Vol 179 ◽

pp. 302-304 ◽

Cited By ~ 1

Author(s):

A. Kniazev ◽

J. Salzer ◽

V. Lipovetsky ◽

T. Boroson ◽

J. Moody ◽

...

Keyword(s):

Emission Line ◽

Rest Frame ◽

Pilot Project ◽

The North ◽

Ccd Detector ◽

Redshift Survey ◽

Objective Prism ◽

Emission Line Galaxies ◽

Digital Survey ◽

North Galactic

We have initiated a major new survey for emission-line galaxies (ELGs) which we call the KPNO International Spectroscopic Survey (KISS). Survey observations began in March 1994 with the 0.61-m Burrell Schmidt telescope. The technique we employ combines the benefits of a traditional photographic objective-prism survey with the advantages of using a CCD detector. The field of view of our CCD is 1.1° square, and the prism employed provides a dispersion of 19 Å/pixel at 5000 Å. The spectral range covered (4800-5500 Å) is restricted by a specially designed filter that transmits from rest-frame Hβ to just shortward of the strong night-sky line at 5577 Å; this greatly reduces the sky background. We expect KISS to be sensitive to galaxies with magnitudes as faint as B = 20m–21m, much deeper than existing photographic surveys. Our initial pilot project covers 100 square degrees (Salzer et al. 1994) and overlaps the CfA/Dartmouth Century Redshift Survey (α = 8h30m–16h45m and δ = 29°–30°) in the North Galactic cap.

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