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

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.

1994 ◽  
Vol 161 ◽  
pp. 709-714
Author(s):  
G. Comte ◽  
C. Surace

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.


1989 ◽  
Vol 134 ◽  
pp. 400-401
Author(s):  
Gordon M. MacAlpine ◽  
John J. Salzer

For the University of Michigan (UM) survey, the Curtis Schmidt telescope at CTIO is used with Kodak IIIa-J plates and the 1.°8 objective prism to detect emission-line galaxies (ELGs) and quasars. Line emission is the primary selection criterion. The quasar sample has been investigated by Lewis, MacAlpine, and Weedman (1979) and by MacAlpine and Feldman (1982) while a study of the ELGs was begun by Lewis (1983). Here, we report on a more extensive analysis of the 172 ELG candidates in the UM Lists IV (MacAlpine and Lewis 1978) and V (MacAlpine and Williams 1981) areas.


1997 ◽  
Vol 159 ◽  
pp. 419-420
Author(s):  
Chulhee Kim

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.


1987 ◽  
Vol 121 ◽  
pp. 53-55
Author(s):  
M. Kalafi ◽  
A. Savage ◽  
A.R. Good ◽  
R.D. Cannon ◽  
M.G. Yates

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.


1986 ◽  
Vol 10 (3) ◽  
pp. 181-189
Author(s):  
Liu Ji-ying ◽  
Huang Yong-wei ◽  
Feng Xing-chun

1979 ◽  
Vol 47 ◽  
pp. 151-153
Author(s):  
T. D. Kinman

Four methods for finding emission-line galaxies have been compared. Method (a) uses the ultraviolet excess, as found either by filter photography (Haro 1956) or by objective prism spectra (Markarian 1967). glanco (1974) introduced a thin prism with the CTIO Schmidt (1740 Å mm-1 at Hβ) which with IIIa-J plates [Method (b)] gave enough resolution for Smith (1975) and MacAlpine et al. (1977a, 1977b) to detect and classify galaxies by strong emission lines. Following a suggestion by McCarthy that even higher dispersion might be useful, I have used the CTIO Schmidt with [Method (c)] the 4° prism, a GGl+55 filter and IIIa-J emulsion and with [Method (d)] the 10° prism, an RG630 filter and IIIa-F emulsion. These latter give about 400 Å mm-1 at Hβ and Hα respectively which improves the visibility of emission lines against the galaxy continuum so that [0111] 5007 and 4959 and Hβ can be seen on the green plates and Hα and [SII] 6725 can be seen on the red plates.


1991 ◽  
Vol 15 (2) ◽  
pp. 131-142
Author(s):  
Huang Yong-wei ◽  
Liu Ji-ying ◽  
Feng Xing-chun

1998 ◽  
Vol 15 (1) ◽  
pp. 152-154
Author(s):  
Alisher S. Hojaev

AbstractFrom a series of 4° objective-prism plates obtained on the 1 m Schmidt telescope of the Byurakan Astrophysical Observatory, 20 new Hα emission line stars were found. The intensity of Hα emission line was evaluated for these stars. An additional sample of probable Hα emission stars was also found. We present here details and some observational features of these stars. The total number of Hα emission line stars estimated for the surveyed area is about 80.


1978 ◽  
Vol 76 ◽  
pp. 64-64
Author(s):  
N. Sanduleak ◽  
D.J. MacConnell ◽  
A.G. Davis Philip

Very deep, blue and red-sensitive objective-prism plates, taken with the Curtis Schmidt telescope at the Cerro Tololo Inter-American Observatory, were used to survey both Magellanic Clouds for unresolved objects which could be classified as highly probable planetary nebulae. The high sensitivity of the baked Kodak IIIa-J emulsion at 5000 Å made it possible to detect the N1 and N2 lines of [OIII] in fainter objects than previously observed. A number of emission-line stars, compact HII regions, and very-low-excitation objects, formerly considered to be probable or possible planetaries, were recognized and excluded. The final lists contain 27 confirmed planetaries in the SMC and 100 in the LMC, a ratio equivalent to the estimated ratio of total mass in the two systems. As would be expected, most of these objects had been detected in previous objective-prism surveys but some apparently new planetaries were found.


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