NGC 4631

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NGC 4631
NGC 4631 HST.jpg
An image of NGC 4631 taken with Hubble Space Telescope
Observation data (J2000 epoch)
Constellation Canes Venatici [1]
Right ascension 12h 42m 08.0s [2]
Declination +32° 32′ 29″ [2]
Redshift 606 ± 3 km/s [2]
Distance 30 Mly
Apparent magnitude  (V)9.8 [2]
Characteristics
Type SB(s)d [2]
Apparent size  (V)15′.5 × 2′.7 [2]
Notable featuresedge-on
Other designations
Whale Galaxy, [3] Arp 281, UGC 7865, PGC 42637, [2] Caldwell  32

NGC 4631 (also known as the Whale Galaxy or Caldwell 32) is a barred spiral galaxy in the constellation Canes Venatici about 30 million light years away from Earth. It was discovered on 20 March 1787 by German-British astronomer William Herschel. [4] This galaxy's slightly distorted wedge shape gives it the appearance of a herring or a whale, hence its nickname. [3] Because this nearby galaxy is seen edge-on from Earth, professional astronomers observe this galaxy to better understand the gas and stars located outside the plane of the galaxy.

Contents

Starburst and superwind

NGC 4631 mosaic of two HST images; 7.2'x2' view NGC 4631 Hubble mosaic.jpg
NGC 4631 mosaic of two HST images; 7.2′x2′ view

NGC 4631 contains a central starburst, which is a region of intense star formation. The strong star formation is evident in the emission from ionized hydrogen [5] and interstellar dust heated by the stars formed in the starburst. [6] The most massive stars that form in star formation regions only burn hydrogen gas through fusion for a short period of time, after which they explode as supernovae. So many supernovae have exploded in the center of NGC 4631 that they are blowing gas out of the plane of the galaxy. This superwind can be seen in X-rays [7] and in spectral line emission. [5] The gas from this superwind has produced a giant, diffuse corona of hot, X-ray emitting gas around the whole galaxy. [8]

Although no supernovae have been observed in NGC 4631 yet, a luminous red nova, designated AT 2021biy, was discovered on 29 January 2021 (type LRN, mag. 18.1). [9]

Nearby galaxies and galaxy group

NGC 4631 has a nearby companion dwarf elliptical galaxy, NGC 4627. NGC 4627 and NGC 4631 together were listed in the Atlas of Peculiar Galaxies as an example of a "double galaxy" or a galaxy pair. [10]

NGC 4631 and NGC 4627 are part of the NGC 4631 Group, a group of galaxies that also includes the interacting galaxies NGC 4656 and NGC 4657. [11] [12] [13] [14] However, exact group identification is problematic because this galaxy and others lie in a part of the sky that is relatively crowded. Estimates of the number of galaxies in this group range from 5 [11] to 27, [14] and all studies identify very different member galaxies for this group.

See also

Related Research Articles

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<span class="mw-page-title-main">Messier 81</span> Spiral galaxy in the constellation Ursa Major

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<span class="mw-page-title-main">Messier 90</span> Galaxy in the constellation Virgo

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<span class="mw-page-title-main">Messier 95</span> Galaxy in the constellation Leo

Messier 95, also known as M95 or NGC 3351, is a barred spiral galaxy about 33 million light-years away in the zodiac constellation Leo. It was discovered by Pierre Méchain in 1781, and catalogued by compatriot Charles Messier four days later. In 2012 its most recent supernova was discovered.

<span class="mw-page-title-main">Messier 108</span> Galaxy in the constellation Ursa Major

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<span class="mw-page-title-main">NGC 3227</span> Galaxy in the constellation Leo

NGC 3227 is an intermediate spiral galaxy that is interacting with the dwarf elliptical galaxy NGC 3226. The two galaxies are one of several examples of a spiral with a dwarf elliptical companion that are listed in the Atlas of Peculiar Galaxies. Both galaxies may be found in the constellation Leo. It is a member of the NGC 3227 Group of galaxies, which is a member of the Leo II Groups, a series of galaxies and galaxy clusters strung out from the right edge of the Virgo Supercluster.

<span class="mw-page-title-main">NGC 4565</span> Galaxy in the constellation Coma Berenices

NGC 4565 is an edge-on spiral galaxy about 30 to 50 million light-years away in the constellation Coma Berenices. It lies close to the North Galactic Pole and has a visual magnitude of approximately 10. It is known as the Needle Galaxy for its narrow profile. First recorded in 1785 by William Herschel, it is a prominent example of an edge-on spiral galaxy.

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<span class="mw-page-title-main">NGC 1566</span> Galaxy in the constellation Dorado

NGC 1566, sometimes known as the Spanish Dancer, is an intermediate spiral galaxy in the constellation Dorado, positioned about 3.5° to the south of the star Gamma Doradus. It was discovered on May 28, 1826 by Scottish astronomer James Dunlop. At 10th magnitude, it requires a telescope to view. The distance to this galaxy remains elusive, with measurements ranging from 6 Mpc up to 21 Mpc.

<span class="mw-page-title-main">NGC 1808</span> Galaxy in the constellation Columba

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<span class="mw-page-title-main">NGC 3169</span> Galaxy in the constellation Sextans

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<span class="mw-page-title-main">NGC 613</span> Galaxy in the constellation of Sculptor

NGC 613 is a barred spiral galaxy located 67 million light years away in the southern constellation of Sculptor. This galaxy was discovered in 1798 by German-English astronomer William Herschel, then re-discovered and catalogued by Scottish astronomer James Dunlop. It was first photographed in 1912, which revealed the spiral form of the nebula. During the twentieth century, radio telescope observations showed that a linear feature in the nucleus was a relatively strong source of radio emission.

<span class="mw-page-title-main">NGC 2782</span> Galaxy in the constellation Lynx

NGC 2782 is a peculiar spiral galaxy that formed after a galaxy merger in the constellation Lynx. The galaxy lies 75 million light years away from Earth, which means, given its apparent dimensions, that NGC 2782 is approximately 100,000 light years across. NGC 2782 has an active galactic nucleus and it is a starburst and a type 1 Seyfert galaxy. NGC 2782 is mentioned in the Atlas of Peculiar Galaxies in the category galaxies with adjacent loops.

<span class="mw-page-title-main">Coma I</span> Galaxy cluster in constellation Coma Berenices

The Coma I Group is a group of galaxies located about 14.5 Mpc (47.3 Mly) away in the constellation Coma Berenices. The brightest member of the group is NGC 4725. The Coma I Group is rich in spiral galaxies while containing few elliptical and lenticular galaxies. Coma I lies in the foreground of the more distant Coma and Leo clusters and is located within the Virgo Supercluster.

<span class="mw-page-title-main">NGC 3367</span> Spiral galaxy in the constellation Leo

NGC 3367 is a barred spiral galaxy located in the constellation Leo. It is located at a distance of about 120 million light years from Earth, which, given its apparent dimensions, means that NGC 3367 is about 85,000 light years across. It was discovered by William Herschel on March 19, 1784.

<span class="mw-page-title-main">NGC 5965</span> Spiral galaxy in the constellation Draco

NGC 5965 is a spiral galaxy located in the constellation Draco. It is located at a distance of circa 150 million light years from Earth, which, given its apparent dimensions, means that NGC 5965 is about 260,000 light years across. It was discovered by William Herschel on May 5, 1788.

<span class="mw-page-title-main">NGC 4302</span> Galaxy in the constellation Coma Berenices

NGC 4302 is an edge-on spiral galaxy located about 55 million light-years away in the constellation Coma Berenices. It was discovered by astronomer William Herschel on April 8, 1784 and is a member of the Virgo Cluster.

References

  1. ↑ R. W. Sinnott, ed. (1988). The Complete New General Catalogue and Index Catalogue of Nebulae and Star Clusters by J. L. E. Dreyer. Sky Publishing Corporation and Cambridge University Press. ISBN   978-0-933346-51-2.
  2. 1 2 3 4 5 6 7 "NASA/IPAC Extragalactic Database". Results for NGC 4631. Retrieved 2006-11-21.
  3. 1 2 "NGC 4631". SIMBAD . Centre de données astronomiques de Strasbourg . Retrieved 2006-08-22.
  4. ↑ Seligman, Courtney. "New General Catalogue Objects: NGC 4631". Celestial Atlas. Retrieved 4 September 2024.
  5. 1 2 R. J. Rand; S. R. Kulkarni; J. J. Hester (1992). "Warm ionized gas in the edge-on galaxies NGC 4565 and NGC 4631". Astrophysical Journal. 396: 97–103. Bibcode:1992ApJ...396...97R. doi: 10.1086/171699 .
  6. ↑ G. J. Bendo; D. A. Dale; B. T. Draine; C. W. Engelbracht; et al. (2006). "The Spectral Energy Distribution of Dust Emission in the Edge-on Spiral Galaxy NGC 4631 as Seen with Spitzer and the James Clerk Maxwell Telescope". Astrophysical Journal. 652 (1): 283–305. arXiv: astro-ph/0607669 . Bibcode:2006ApJ...652..283B. doi:10.1086/508057. S2CID   119419587.
  7. ↑ Q. D. Wang; R. A. S. Walterbos; M. F. Steakley; C. A. Norman; et al. (1994). "ROSAT detection of diffuse hot gas in the edge-on galaxy NGC 4631". Astrophysical Journal. 439: 176–184. Bibcode:1995ApJ...439..176W. doi:10.1086/175162. hdl: 2060/19950011081 . S2CID   121407361.
  8. ↑ Q. D. Wang; S. Immler; R. Walterbos; J. T. Lauroesch; et al. (2001). "Chandra Detection of a Hot Gaseous Corona around the Edge-on Galaxy NGC 4631". Astrophysical Journal. 555 (2): L99–L102. arXiv: astro-ph/0105541 . Bibcode:2001ApJ...555L..99W. doi:10.1086/323179. S2CID   15558867.
  9. ↑ Transient Name Server entry for AT 2021biy. Retrieved 10 November 2023.
  10. ↑ H. Arp (1966). "Atlas of Peculiar Galaxies". Astrophysical Journal Supplement. 14: 1–20. Bibcode:1966ApJS...14....1A. doi:10.1086/190147.
  11. 1 2 R. B. Tully (1988). Nearby Galaxies Catalog. Cambridge: Cambridge University Press. ISBN   978-0-521-35299-4.
  12. ↑ P. Fouque; E. Gourgoulhon; P. Chamaraux; G. Paturel (1992). "Groups of galaxies within 80 Mpc. II - The catalogue of groups and group members". Astronomy and Astrophysics Supplement. 93: 211–233. Bibcode:1992A&AS...93..211F.
  13. ↑ A. M. Garcia (1993). "General study of group membership. II - Determination of nearby groups". Astronomy and Astrophysics Supplement. 100: 47–90. Bibcode:1993A&AS..100...47G.
  14. 1 2 G. Giuricin; C. Marinoni; L. Ceriani; A. Pisani (2000). "Nearby Optical Galaxies: Selection of the Sample and Identification of Groups". Astrophysical Journal. 543 (1): 178–194. arXiv: astro-ph/0001140 . Bibcode:2000ApJ...543..178G. doi:10.1086/317070. S2CID   9618325.
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