Whale galaxy
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. | |
AladinLite | |
Constellation | Hunting dogs |
Position equinox : J2000.0 , epoch : J2000.0 |
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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
- Panorama of the Whale Galaxy - Astronomy Picture of the Day of May 17, 2010.
- NGC 4631: The Whale Galaxy - Astronomy Picture of the Day of March 29, 2002 (English).
- Chandra
- The whale galaxy at SEDS
- Spektrum.de : Amateur recordings [1]
- ARP ATLAS OF PECULIAR GALAXIES
- Seligman Arp
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