Whale galaxy

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Galaxy
whale galaxy / NGC 4631
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Image of the elongated galaxy NGC 4631 and the smaller, overlying galaxy NGC 4627 (Arp 281) with a 60 cm telescope.
Image of the elongated galaxy NGC 4631 and the smaller, overlying galaxy NGC 4627 (Arp 281) with a 60 cm telescope.
AladinLite
Constellation Hunting dogs
Position
equinox :  J2000.0 , epoch : J2000.0
Right ascension 12 h 42 m 08.0 s
declination + 32 ° 32 ′ 29 ″
Appearance
Morphological type SB (s) d / HII  
Brightness  (visual) 9.0 mag
Brightness  (B-band) 9.7 likes
Angular expansion 15.2 ′ × 2.8 ′
Position angle 86 °
Surface brightness 12.9 mag / arcmin²
Physical data
Affiliation NGC-4631 group
(LGG 291)  
Redshift 0.002021 ± 0.000010  
Radial velocity (606 ± 3) km / s  
Stroke distance
v rad  / H 0 		(28 ± 2)  x  10 6  ly
(8.58 ± 0.6)  Mpc 
diameter 115,000 ly
history
discovery Wilhelm Herschel
Discovery date March 20, 1787
Catalog names
NGC  4631 • UGC  7865 • PGC  42637 • CGCG  188-016 • MCG  + 06-28-20 • IRAS  12396 + 3249 • KUG  1239 + 328B • 2MASX  J12420800 + 3232294 • Arp  part of 281 • GC  3165 • H  V 42 • h  1397 • KCPG 350A • Stile 442A

The Whale Galaxy or NGC 4631 , sometimes also known as the Herring Galaxy , is a bar-spiral galaxy about 28 million light years away from the Milky Way . Its apparent visual brightness is 9.0  mag , its angular extent 15.2 '× 2.8'.

NGC 4627 is a companion galaxy to the whale galaxy and is approximately 2.6 'northwest of its center; the two galaxies are listed together in the Arp catalog as Arp 281. The small neighboring galaxy NGC 4627 causes a certain deformation of the whale galaxy. In addition, it seems to have come close to the neighboring galaxy NGC 4656/57 more often in the past , as is still evident today from hydrogen and other gas residues that are located between the two galaxies. Halton Arp organized his catalog of unusual galaxies into groups according to purely morphological criteria. This galaxy pair belongs to the class double galaxies with inflow and attraction .

The whale galaxy is about the size of the Milky Way and was discovered by William Herschel on March 20, 1787 .

Of particular interest is the hot gas halo that surrounds the galaxy and extends up to 25,000 light years from the galactic plane. High-resolution images of the X-ray emission of the halo were obtained from the research satellite Chandra . It is believed that the Milky Way galaxy is also surrounded by a similar halo.

Web links

Commons : NGC 4631  - collection of images, videos, and audio files

literature

  • Jeff Kanipe and Dennis Webb: The Arp Atlas of Peculiar Galaxies - A Chronicle and Observer's Guide , Richmond 2006, ISBN 978-0-943396-76-7

Individual evidence

  1. ↑ a b c d e NASA / IPAC EXTRAGALACTIC DATABASE
  2. ↑ a b c d e SEDS : NGC 4631
  3. ↑ Seligman