Sign on

SAO/NASA ADS Astronomy Abstract Service


· Find Similar Abstracts (with default settings below)
· Full Refereed Journal Article (PDF/Postscript)
· Full Refereed Scanned Article (GIF)
· References in the article
· Citations to the Article (27) (Citation History)
· Refereed Citations to the Article
· NED Objects (1)
· Associated Articles
· Reads History
·
· Translate This Page
Title:
Planetary nebulae in local group galaxies. VI - an observational determination that M32 is in front of M31
Authors:
Ford, H. C.; Jacoby, G. H.; Jenner, D. C.
Affiliation:
AA(California, University, Los Angeles, Calif.), AB(California, University, Los Angeles, Calif.), AC(California, University, Los Angeles, Calif.)
Publication:
Astrophysical Journal, Part 1, vol. 223, July 1, 1978, p. 94-97. Research supported by the University of California (ApJ Homepage)
Publication Date:
07/1978
Category:
Astronomy
Origin:
STI
NASA/STI Keywords:
Andromeda Galaxy, Elliptical Galaxies, Local Group (Astronomy), Planetary Nebulae, Radio Astronomy, Astronomical Maps, Color, Gravitational Effects, Interstellar Extinction, Spectral Line Width
DOI:
10.1086/156239
Bibliographic Code:
1978ApJ...223...94F

Abstract

Twenty-one-centimeter integrated brightness maps of M31 are used to predict a color excess E(B - V) of approximately 0.5 if M32 is behind M31. A galactic cosecant law applied to M31 predicts a color excess between 0.5 and 0.6. It is concluded that M32 will be heavily reddened if it is behind M31. The predicted value of H-alpha/H-beta intensity ratio is 5.1 for a nebula in M32 if M32 is behind M31, whereas the predicted ratio is 3.2 if M32 is in front of M31. The observed ratio (2.96) in the planetary nebula M32-1 agrees with the latter value within the observational uncertainty. This is taken to be strong evidence that M32 is in front of M31. Additional arguments in favor of this conclusion are (1) the absence of dust clouds silhouetted against M32; (2) the absence of known visual absorption and color gradients across M32; and (3) the inconsistency of the intrinsic color of M32 and its integrated line strengths if it is behind M31. All considerations lead to the conclusion that M32 must be in front of M31. Byrd (1976) showed that gravitational perturbation by M32 can account for the velocity and morphological anomalies observed in M31. The encounter orbit which best reproduces the anomalies places M32 at the present time near to and in front of M31. It is concluded that the basic picture of gravitational perturbation of M31 by M32 is correct.

Associated Articles

Part  1     Part  2     Part  3     Part  4     Part  5     Part  6     Part  8     Part  7     Part  9    


Printing Options

Print whole paper
Print Page(s) through

Return 600 dpi PDF to Acrobat/Browser. Different resolutions (200 or 600 dpi), formats (Postscript, PDF, etc), page sizes (US Letter, European A4, etc), and compression (gzip,compress,none) can be set through the Printing Preferences



More Article Retrieval Options

HELP for Article Retrieval


Bibtex entry for this abstract   Preferred format for this abstract (see Preferences)


Find Similar Abstracts:

Use: Authors
Title
Keywords (in text query field)
Abstract Text
Return: Query Results Return    items starting with number
Query Form
Database: Astronomy
Physics
arXiv e-prints