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Open Astronomy

formerly Baltic Astronomy

Editor-in-Chief: Barbuy, Beatriz

IMPACT FACTOR 2017 (Baltic Astronomy): 0.417
5-year IMPACT FACTOR (Baltic Astronomy): 0.486

CiteScore 2017: 0.16

SCImago Journal Rank (SJR) 2017: 0.131
Source Normalized Impact per Paper (SNIP) 2017: 0.109

ICV 2017: 121.03

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Volume 25, Issue 4


Unusual Objects in the Spiral Galaxy NGC 6946

Yu. N. Efremov
  • Sternberg Astronomical Institute, M. V. Lomonosov Moscow State University, Universitetskij pr. 13, Moscow 119899, Russian Federation
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Published Online: 2017-03-09 | DOI: https://doi.org/10.1515/astro-2017-0255


Several strange objects in the spiral galaxy NGC 6946 are described. One of these objects is the giant stellar complex noted long ago; we suggested that its sharp semicircular western edge is a result of the ram pressure, arising owing to motion of this complex through the HI halo of NGC 6946. We found another enigmatic object, proposing for it the name Red Ellipse; it is located within the isolated Northern arm of the galaxy. The enormous size of this Ellipse, and especially the spectroscopic data obtained recently with the 6-m reflector of the Special Astrophysical Observatory, made us to conclude that this object could not be a supernova remnant. The excellent image of NGC 6946 obtained with the Subaru 8-m telescope also shows a strange region with several regular crossed dark lanes, connected with a black spot.

Keywords: galaxies: individual: NGC 6946; galaxies: spiral; galaxies: star formation


About the article

Received: 2016-11-22

Accepted: 2016-12-14

Published Online: 2017-03-09

Published in Print: 2016-12-01

Citation Information: Open Astronomy, Volume 25, Issue 4, Pages 369–376, ISSN (Online) 2543-6376, DOI: https://doi.org/10.1515/astro-2017-0255.

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© 2016 Yu. N. Efremov, published by De Gruyter Open. This work is licensed under the Creative Commons Attribution-NonCommercial-NoDerivatives 3.0 License. BY-NC-ND 3.0

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