The Case low-dispersion Northern Sky Survey. VI - A-F stars in a region near the north Galactic pole

We present results of the optical identification of a spatially complete, flux limited sample of about 700 ROSAT All-Sky X-ray sources contained in 6 study areas north of δ = −9° with |bII|> 20° (including one region near the North Galactic pole (NGP), another one near the North Ecliptic pole (NEP)). Countrate limits are 0.01 cts s–1 near the NEP and 0.03 cts s–1 for the other areas. The optical observations were performed at the 2.15-m telescope of the Guillermo Haro Observatory, Mexico, using the Landessterwarte Faint Object Spectrograph Camera which allows to carry out direct CCD imaging and multi-object spectroscopy. The limiting magnitude is about 19m for spectroscopy and about 23m for B and R direct imaging. Our analysis shows a dependency of the ratio of ‘extragalactic’ (e.g., AGN, cluster of galaxies) to ‘stellar’ (e.g., coronal emitters, active binaries) counterparts on NH. In the area near the NGP (low NH) ‘extragalactic’ counterparts dominate, while in the area with the highest NH ‘stellar’ counterparts dominate.

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The Performance of Neural Networks in Astronomical Image Classification

Symposium - International Astronomical Union ◽

10.1017/s0074180900047380 ◽

1994 ◽

Vol 161 ◽

pp. 235-241

Author(s):

S.C. Odewahn

Keyword(s):

Neural Network ◽

Image Classification ◽

Sky Surveys ◽

Pattern Recognition Techniques ◽

The North ◽

Astronomical Image ◽

Sky Survey ◽

Network Pattern ◽

North Galactic

The use of neural network pattern recognition techniques in the field of astronomy is reviewed. In assessing the quality of image recognition derived from this method particular attention is given to the problem of star/galaxy discrimination in large digital sky surveys. A two color survey of 9 fields of the first epoch Palomar Sky Survey, centered on the North Galactic Pole, has been performed with the Minnesota Automated Plate Scanner. A set of neural network image classifiers are used to automatically perform star/galaxy discrimination. We assess the efficiency of image classification and sample completeness through comparisons with a variety of independent studies of the NGP area.

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The Frequency of Faint M Giant Stars at High Galactic Latitudes

Highlights of Astronomy ◽

10.1017/s153929960000294x ◽

1977 ◽

Vol 4 (2) ◽

pp. 35-36 ◽

Cited By ~ 3

Author(s):

N. Sanduleak

Keyword(s):

Main Sequence ◽

Galactic Plane ◽

Absolute Magnitude ◽

Main Sequence Stars ◽

Giant Stars ◽

The North ◽

Objective Prism ◽

M Stars ◽

Low Dispersion ◽

North Galactic

Based on the observations of M giant stars in the north galactic polar objective-prism survey of Upgren (1960) and the data summarized by Blanco (1965) the overall space density of all M-type giants as a function of distance from the galactic plane at the position of the sun can be approximated by,where z is in kpc and ρ(z) is the number of stars per 106 pc3. This relationship is derived from the observed fall-off in space densities up to a distance of about 2 kpc.The question arises as to the validity of extrapolation equation (1) to larger z distances so as to predict the number of faint M giants expected per unit area near the galactic poles. Adopting for the M giants a mean visual absolute magnitude of −1.0 (Blanco 1965), one finds that equation (1) predicts that less than one giant fainter than V~12 should be expected in a region of 200 square degrees. This expectation formed the hypothesis of a thesis study (Sanduleak 1965) in which it was assumed that the very faint M stars detected in a deep, infrared objective-prism survey at the NGP were main-sequence stars, since this could not be ascertained spectroscopically on the very low-dispersion plates used.

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The Case Low-Dispersion Northern Sky Survey. XIV - A-F stars in a region in southern Canes Venatici

The Astrophysical Journal Supplement Series ◽

10.1086/191786 ◽

1993 ◽

Vol 86 ◽

pp. 453 ◽

Cited By ~ 3

Author(s):

D. J. MacConnell ◽

C. B. Stephenson ◽

Peter Pesch

Keyword(s):

Sky Survey ◽

F Stars ◽

Low Dispersion

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Studies of A and F Stars in the Region of the North Galactic Pole-III Interstellar Reddening

Monthly Notices of the Royal Astronomical Society ◽

10.1093/mnras/176.1.175 ◽

1976 ◽

Vol 176 (1) ◽

pp. 175-180 ◽

Cited By ~ 8

Author(s):

R. W. Hilditch ◽

G. Hill ◽

J. V. Barnes

Keyword(s):

The North ◽

F Stars ◽

North Galactic

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Studies of A and F Stars in the Region of the North Galactic Pole

Highlights of Astronomy ◽

10.1007/978-94-010-1250-8_24 ◽

1977 ◽

pp. 71-71

Author(s):

R. W. Hilditch ◽

Graham Hill

Keyword(s):

The North ◽

F Stars ◽

North Galactic

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QSO Color Selection in the SDSS

Symposium - International Astronomical Union ◽

10.1017/s0074180900128815 ◽

1998 ◽

Vol 179 ◽

pp. 291-292

Author(s):

H. J. Newberg ◽

B. Yanny

Keyword(s):

Critical Path ◽

Color Space ◽

Sloan Digital Sky Survey ◽

Radio Sources ◽

Color Selection ◽

The North ◽

Point Spread ◽

Sky Survey ◽

Spread Function ◽

North Galactic

The Sloan Digital Sky Survey (SDSS) will image 10,000 square degrees in the north galactic cap in five filters. We hope to identify and obtain spectra for about 100,000 quasars brighter than 20th magnitude in this area. The selection will be primarily on the basis of point spread function and colors, but we will also identify quasars from a catalog of FIRST radio sources. The selection areas in color space must be determined during the testing period prior to the official start of the survey. This task may determine the length of the test period. In anticipation of this becoming the critical path, we have written a body of software that will allow us to quickly analyze a set of multicolor data and make a first cut at the selection limits.

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