Objective-Prism Surveys of the Galaxy

1994 ◽  
pp. 467-469 ◽  
Author(s):  
O. Kurtanidze ◽  
M. Nikolashvili
Keyword(s):  
The Galaxy ◽  
Objective Prism

scholarly journals Determination of the C/M5+ Ratio in the Galactic Disk

1995 ◽  
Vol 148 ◽  
pp. 276-279
Author(s):  
Francisco J. Fuenmayor
Keyword(s):  
Near Infrared ◽  
Galactic Center ◽  
Galactic Disk ◽  
Mean Value ◽  
Galactocentric Distance ◽  
The Galaxy ◽  
Metal Abundance ◽  
Objective Prism ◽  
M Stars

AbstractA determination of the C/M5+ ratio, as a function of the galactocentric distance, in the galactic disk is presented. These results are based upon previous determinations of the space density for cool carbon stars and for late giant M stars in the Milky Way. Most of these results were obtained from objective-prism surveys in the near infrared using mainly Schmidt-type telescopes. The ratio C/M5+ appears to increase from 0.05 to 0.25 in the galactic disk, from the galactic center outwards. A mean value of 0.15 of this ratio for the Galaxy is suggested. Correlations between the C/M5+ ratio and currently known metal abundance gradients in the galactic disk are discussed.

scholarly journals Comments on the Detection and Classification of Compact Emission-Line Galaxies

1979 ◽  
Vol 47 ◽  
pp. 151-153
Author(s):  
T. D. Kinman
Keyword(s):  
Emission Line ◽  
Emission Lines ◽  
Ultraviolet Excess ◽  
Strong Emission ◽  
The Galaxy ◽  
Objective Prism ◽  
Emission Line Galaxies

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.

scholarly journals Objective-Prism Surveys of the Galaxy

1994 ◽  
Vol 161 ◽  
pp. 467-469 ◽  
Author(s):  
O. Kurtanidze ◽  
M. Nikolashvili
Keyword(s):  
Milky Way ◽  
Late Type ◽  
The Galaxy ◽  
Objective Prism ◽  
Low Dispersion

The main sources of data for low dispersion objective-prism surveys of the Milky Way undertaken in the last fifteen years for the study of the distribution of late type stars, namely M and C stars, are summarized in Table 1.

scholarly journals Planetary nebulae in the central region of the Galaxy

1964 ◽  
Vol 20 ◽  
pp. 41-45 ◽  
Author(s):  
L. Perek
Keyword(s):  
Central Region ◽  
Surface Brightness ◽  
Large Scale ◽  
Direct Determination ◽  
Planetary Nebulae ◽  
Galactic Centre ◽  
Large Numbers ◽  
The Galaxy ◽  
Objective Prism

Planetary nebulae are convenient objects for studying the large-scale structure of the Galaxy. Firstly, they are easily recognized up to considerable distances on plates taken through an objective prism, and secondly, methods have been devised by various authors to determine their distances from two observable quantities: angular diameter and surface brightness. The importance of the subsystem of planetary nebulae has been accentuated especially by the discoveries by Minkowski and Haro of large numbers of planetaries in the direction of the galactic centre. The distribution of planetaries on the sphere suggests that they are connected with the galactic nucleus, but no direct determination of their distances, which would either confirm or contradict this statement, is available. The most serious obstacle in studying the subsystem of planetaries is the lack of observing data. The aim of the reported paper (Perek 1963) is to give a tentative outline of the distribution of planetaries in space based on extensive new observing material.

scholarly journals Tracing Large-Scale Structure with Galaxy Objective-Prism Spectra

1988 ◽  
Vol 130 ◽  
pp. 525-525
Author(s):  
Q.A. Parker ◽  
H.T. Macgillivray ◽  
S.M. Beard
Keyword(s):  
Large Scale ◽  
Large Scale Structure ◽  
Scale Structure ◽  
Early Type ◽  
Galaxy Distribution ◽  
Large Numbers ◽  
The Galaxy ◽  
Measured Sample ◽  
Objective Prism ◽  
Low Dispersion

A new and promising use of galaxy objective-prism spectra as a means of highlighting features in the large scale galaxy distribution has been recently reported by Parker et al. (1987). The technique relies on the property that galaxies with identifiable 4000Å features in low dispersion objective-prism spectra are mostly ellipticals (Cooke, 1980), and that early type galaxies seem to delineate structure and clumpiness in the galaxy distribution (e.g. Giovanelli and Haynes, 1982). The effect is most striking when large numbers of objective-prism galaxy spectra are considered. Figure 1 gives the X-Y plot for 1539 galaxies with 4000Å features to Bj=18.7 in one UKST field out of a manually measured sample of 2903 galaxy prism spectra. Substantial clumpiness is evident. This technique can trace structure in the galaxy distribution across many UKST fields to depths of 400 h−1Mpc.

scholarly journals A Low-Dispersion, Near-Infrared Survey for Galactic M Supergiants

1986 ◽  
Vol 116 ◽  
pp. 123-124
Author(s):  
D. J. MacConnell ◽  
R. F. Wing ◽  
E. Costa
Keyword(s):  
Interstellar Dust ◽  
Near Infrared ◽  
Galactic Plane ◽  
Galactocentric Distance ◽  
The Galaxy ◽  
Red Supergiants ◽  
Objective Prism ◽  
Low Dispersion ◽  
Infrared Survey

While there have been many surveys for luminous, blue galactic stars and their numbers can be considered somewhat complete, such is not the case for red supergiants (see e.g. Humphreys and McElroy 1984). One result of this incompleteness is that the ratios B/R and WR/R, often used as diagnostics for evolutionary models of massive stars and the variation of the ratios with galactocentric distance, are not well known for the Galaxy. In an attempt to improve the statistics, the first author began an objective-prism survey within 6 deg of the southern galactic plane using I-N plates. The dispersion is 3400 A/mm at the A-band, and the spectra cover the range 6800–8800 A; the deepest plates reach ir mag ∼13. The detection of possible M supergiants on such plates was first discussed by Nassau, et al. (1954) and depends on the presence of TiO at 7054 A and a spectrum sharply tapered to the blue. For supergiants, this shape results from integration of interstellar dust over a long path-length, but any sample of red stars with tapered spectra contains M giants in heavily-obscured regions and S stars; thus follow-up observations of the candidate stars are necessary.

scholarly journals Recent Developments in the Work on Automated Spectral Classification by Means of Objective Prism Spectra

1994 ◽  
Vol 161 ◽  
pp. 253-254
Author(s):  
V. Malyuto ◽  
T. Shvelidze
Keyword(s):  
Spectral Classification ◽  
Proper Motions ◽  
Stellar Spectra ◽  
Meridional Section ◽  
Spectrometric Data ◽  
Software Packages ◽  
The Galaxy ◽  
Recent Developments ◽  
Objective Prism

Some years ago a complex programme of studying the main meridional section of the Galaxy was started by astronomers of Kiev, Tartu, Abastumani and Vilnius Observatories with the aim of improving our knowledge of spatial and kinematic characteristics of stellar populations. Characteristic to the programme is the use of absolute proper motions of stars together with automated quantitative spectral classification for large stellar-statistical samples. The data are gathered in areas lying within 30° of the main meridional section of the Galaxy. To classify stars, objective prism stellar spectra of intermediate dispersion (166 å/mm at Hγ), obtained with the 70 cm meniscus telescope at the Abastumani Astrophysical Observatory, are used. The field diameter is 4° 50′, and the limiting photographical stellar magnitude is about 12 m . Our system of automated quantitative spectral classification of F-K stars applies criteria evaluation and is mainly based on two software packages: the SDR package for spectrometric data reduction and the CTATEC-2 package determining the linear regression model used for classification (Malyuto & Shvelidze 1989; Malyuto, Pelt & Shvelidze 1993).

scholarly journals A Search for Galactic Carbon Stars

1988 ◽  
Vol 108 ◽  
pp. 48-49
Author(s):  
Hideo Mabhara
Keyword(s):  
Galactic Plane ◽  
Carbon Star ◽  
Spectral Features ◽  
Spectral Classification ◽  
Carbon Stars ◽  
Schmidt Telescope ◽  
Infrared Wavelength ◽  
V Band ◽  
The Galaxy ◽  
Objective Prism

The carbon star is one of the best probes for the galactic study; (1)it is intrinsically bright (Mbol = − 2 to − 6) especially in the red and infrared wavelength regions,(2)it has spectral features readily detectable on objective prism plates due to their strong carbon molecular bands,(3)it is an evolved star distributed abundantly (∼1 star per square degree) along the galactic plane.We can detect it in the Galaxy up to several kpc from the sun on objective prism plates of the Schmidt telescope.We have been making survey observations of faint cool carbon stars using the Kiso 105-cm Schmidt telescope. Kodak IN and 103aF plates are respectively taken behind the 4-degree objective prism (700 Åmm−1 at Hα) for the detection and for the spectral classification. V-band plates are utilized to obtain the position and the brightness of the stars detected.The survey areas are distributed along the northern galactic plane. Seven fields in the Cassiopeia region (l = 115° to 133° and eight fields in the Taurus-Auriga-Gemini region (i = 170° to 188°) have been observed and processed up to now (Maehara and Soyano 1987a,b).

scholarly journals A Deep Survey for Faint Galactic Wolf-Rayet Stars

1991 ◽  
Vol 143 ◽  
pp. 591-594 ◽  
Author(s):  
M.M. Shara ◽  
M. Potter ◽  
A.F.J. Moffat ◽  
L.F. Smith
Keyword(s):  
Milky Way ◽  
Massive Stars ◽  
Mass Function ◽  
Initial Mass Function ◽  
Initial Mass ◽  
The Galaxy ◽  
Deep Survey ◽  
Visual Magnitude ◽  
Objective Prism

Surveys of the Galaxy for Wolf-Rayet (WR) stars are mostly based on objective prism searches, and are generally complete to only about 13th visual magnitude. We are using direct narrowband and broadband Schmidt plates to survey large areas of the southern Milky Way for WR stars to 17-18th magnitude. We expect to find more than 50 new WR stars. The newly detected stars should be among the most distant and/or reddened known in the Galaxy. The survey is also designed to test the completeness of previous bright WR star surveys, and thus to help settle debates over the Initial Mass Function of the most massive stars. We have now located 13 new WR stars in a 40 square degree region in Carina where 24 WR stars were already known. A 25% incompleteness in detection of WR stars as close as 2-3 kpc is suggested.

scholarly journals Is NGC 2242 a New Planetary Nebula?

1989 ◽  
Vol 131 ◽  
pp. 62-62
Author(s):  
Liu Jiying ◽  
Huang Yongwei ◽  
Feng Xingchun
Keyword(s):  
Planetary Nebula ◽  
Emission Lines ◽  
Schmidt Telescope ◽  
Master List ◽  
The Galaxy ◽  
Interesting Object ◽  
Objective Prism

An interesting object was found on the IIIaJ objective prism plate SP1270, taken on Jan. 12.6 UT, 1983 with the Beijing Observatory 60/90-cm Schmidt telescope plus 5°.3 objective prism with a dispersion of 580 A/mm at Hγ. The emission lines [O III]λλ4959+5007 and Hβ were extremely strong. The lines Hγ—Hδ and [O II]λ3727, all in emission, were broad and conspicuous. Two prominent emissions were tentatively identified as He II λ4686 and He II λ4542. Of all these lines none showed any noticeable redshift. It belongs to the Galaxy. The overall spectrum looked like that of a planetary nebula. But on the POSS overlay this object was designated as RNGC 2242 and ZWG 204.005. It was listed as a galaxy either in ZWG, or in A Master List of Nonstellar Optical Astronomical Objects, but it was absent from any previous catalogues of the planetary nebula.

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