scholarly journals An Emission-Line Galaxy Survey with the UK Schmidt Telescope

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.

scholarly journals An Objective-Prism Survey of Emission-Line Galaxies

1997 ◽  
Vol 159 ◽  
pp. 419-420
Author(s):  
Chulhee Kim
Keyword(s):  
Emission Line ◽  
Emission Feature ◽  
Schmidt Telescope ◽  
Objective Prism ◽  
Emission Line Galaxies ◽  
The Uk ◽  
Line Galaxy

AbstractIn order to discover emission-line galaxy (ELG) candidates towards the Hydra Void, an objective-prism survey was undertaken. As a first step, five fields were observed with the UK Schmidt Telescope, and we discovered a total of 33 candidates on a single prism plate through the [O III] λλ4959, 5007 emission feature.

An Emission-Line Galaxy Survey with the UK Schmidt Telescope

1987 ◽  
pp. 53-55
Author(s):  
M. Kalafi ◽  
A. Savage ◽  
A. R. Good ◽  
R. D. Cannon ◽  
M. G. Yates
Keyword(s):  
Emission Line ◽  
Schmidt Telescope ◽  
The Uk ◽  
Line Galaxy

scholarly journals Objective-Prism Galaxy Redshifts in Fields Around the South Galactic Pole

1984 ◽  
Vol 78 ◽  
pp. 405-408 ◽  
Author(s):  
Q.A. Parker ◽  
H.T. MacGillivray ◽  
R.J. Dodd ◽  
J.A. Cooke ◽  
S.M. Beard ◽  
...  
Keyword(s):  
Large Scale ◽  
Schmidt Telescope ◽  
The South ◽  
Large Numbers ◽  
Objective Prism ◽  
The Uk

AbstractMeasurements made with the COSMOS machine on deep objectiveprism photographs taken with the UK 1.2m Schmidt Telescope are being used to obtain approximate redshifts (accurate to ~ 0.01 in z) for large numbers of galaxies in fields near the South Galactic Pole. The data are suitable for investigations of the distribution of galaxies, such as the detection of large-scale density enhancements or voids.

scholarly journals An Automatic Approach for Selecting New HA Emission-Line Galaxies

1994 ◽  
Vol 161 ◽  
pp. 611-614
Author(s):  
O. Alonso ◽  
J. Zamorano ◽  
M. Rego ◽  
J. Gallego ◽  
A.G. Vitores
Keyword(s):  
Emission Line ◽  
Selection Criterion ◽  
Schmidt Telescope ◽  
Objective Prism ◽  
Emission Line Galaxies ◽  
Calar Alto ◽  
Observational Procedure

The most unambiguous way to discover new emission-line galaxies (ELGs) is directly by the presence of their lines, using objective-prism plates of adequate resolution. The first survey using this technique was developed by Smith in 1975 with the 0.6 m CTIO Curtis Schmidt Telescope. The Universidad Complutense de Madrid (UCM) is carrying out a survey of ELGs with the Schmidt Telescope at Calar Alto (Almería, Spain) using the presence of Ha in emission in IIIa-F prism plates as selection criterion. The observational procedure and results are described in Rego et al. 1989; Zamorano et al. 1990; Zamorano et al. 1993.

scholarly journals Deep Wide-field Hα Images of the Magellanic Clouds

1999 ◽  
Vol 190 ◽  
pp. 95-96
Author(s):  
D. H. Morgan ◽  
Q. A. Parker ◽  
S. Phillipps
Keyword(s):  
Emission Line ◽  
Magellanic Clouds ◽  
Wide Area ◽  
Wide Field ◽  
Schmidt Telescope ◽  
Preliminary Results ◽  
Fine Grained ◽  
The Uk

A new Hα survey of the Magellanic Clouds which is being carried out on fine-grained Tech-Pan emulsion with the UK 1.2m Schmidt Telescope will have the best combination of depth and resolution of any that cover such a wide area in and around the Magellanic Clouds. Preliminary results show that the films will provide identifications of new emission-line stars and nebulae.

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

2019 ◽  
Vol 490 (3) ◽  
pp. 3667-3678 ◽  
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.

scholarly journals Slitless Spectroscopy by Photographic and CCD Detectors Across Large Fields

1994 ◽  
Vol 161 ◽  
pp. 709-714
Author(s):  
G. Comte ◽  
C. Surace
Keyword(s):  
Emission Line ◽  
Emission Lines ◽  
Photographic Emulsion ◽  
Subsequent Reduction ◽  
Schmidt Telescope ◽  
Ccd Array ◽  
Objective Prism ◽  
Emission Line Galaxies ◽  
Ccd Detectors

We present a new survey of emission line galaxies, performed with the ESO 1 m Schmidt telescope equipped with the 4° objective prism using IIIa-J photographic emulsion. The plates are digitized with the MAMA microdensitometer. A subsequent reduction of the block scans gives redshifts with a mean accuracy of 160 km/s−1, and spectrophotometric measurements of the intensity and equivalent widths of the principal emission lines. A brief discussion is given of the possible extension of quantitative reduction of slitless spectroscopy to archive plates and future large CCD array frames.

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

2004 ◽  
Vol 128 (5) ◽  
pp. 2073-2079 ◽  
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

Fibre Optics at the UK Schmidt Telescope

1984 ◽  
Vol 5 (4) ◽  
pp. 579-580 ◽  
Author(s):  
F. G. Watson ◽  
J. A. Dawe
Keyword(s):  
Large Scale ◽  
Variable Stars ◽  
Schmidt Telescope ◽  
General Survey ◽  
Surface Distribution ◽  
Fibre Optics ◽  
Redshift Surveys ◽  
Information Advantage ◽  
The Uk ◽  
Very High

The four-fold advantage over a conventional 4 m reflector which naive information theory confers on the 1.2 m UK Schmidt telescope (Dawe and Watson 1982, Watson 1983) is only approachable in practice under certain rather specific conditions. These relate principally to the surface distribution on the sky of the object classes of interest, and the type of detection employed. Clearly, for general survey work with sky-limited photographic detection, the information advantage is high, but it can be demonstrated (Dawe and Watson 1983) that the relatively new technique of multi-object fibre-optics spectroscopy (eg Hill et al. 1980, 1982, Gray 1983, Lund and Enard 1983) with linear detectors offers very high potential in certain regimes of operation. In particular, the UK Schmidt telescope (UKST) equipped with 400 fibre channels has four times the effective light grasp (= number of fibres utilized × aperture) of a 4 m reflector (with a 1 deg field and equipped with any number of fibres) for target objects with surface densities between approximately 1 and 10 per square degree (Dawe and Watson 1983). Objects ranging from galactic variable stars to quasars lie within these limits, but of especial interest are galaxies, whose apparent luminosity function in this range of surface densities runs from magnitudes 15 to 17 (MacGillivray, private communication). Large-scale, medium accuracy (60 km s−1) redshift surveys of galaxies within this magnitude range promise to be extremely fruitful (Davis 1982) and are easily within the reach of the UKST fibre-coupled to a CCD spectrograph (Watson and Dawe 1984).

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

2020 ◽  
Vol 499 (3) ◽  
pp. 3943-3960 ◽  
Author(s):  
Hui Kong ◽  
Kaylan J Burleigh ◽  
Ashley Ross ◽  
John Moustakas ◽  
Chia-Hsun Chuang ◽  
...  
Keyword(s):  
Emission Line ◽  
Large Scale ◽  
Three Dimensional ◽  
Selection Function ◽  
Imaging Data ◽  
Scientific Analysis ◽  
Galaxy Sample ◽  
Systematic Biases ◽  
Redshift Survey ◽  
Emission Line Galaxies

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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