NGC 3631 explained

NGC 3631
Epoch:J2000
Type:SA(s)c [1]
Dist Ly:33.7 ± 17.7 Mly (10.3 ± 5.4 Mpc)
Z:1.156 ± 1 km/s
Appmag V:10.1
Size V:5.0 × 4.8
Constellation Name:Ursa Major
Names:UGC 6360, Arp 27, MCG +09-19-047, VV 363, PGC 34767

NGC 3631 is a spiral galaxy located in the constellation Ursa Major. It is located at a distance of about 35 million light years from Earth, which, given its apparent dimensions, means that NGC 3631 is about 60,000 light years across. It was discovered by William Herschel on April 14, 1789.[2] It is a grand design spiral galaxy seen face on.

Characteristics

NGC 3631 is a grand design spiral galaxy and features two principal spiral arms, which begin near the center. The two main arms branch into secondary arms with lower surface brightness. The galaxy shows moderate-to-high star formation rate and bright HII regions are present in all the arms.[3] The star formation rate of the galaxy is 4.6 per year.[4] Halton Arp observed "straight arms", and an "absorption tube crossing from inside to outside of southern arm" and added the galaxy to his Atlas of Peculiar Galaxies.[5] At inclination of 17 degrees,[5] the galaxy is seen nearly face on.

The HI imaging shows the spiral arms distinguished well and HI is also detected in most of the interarm regions. The atomic hydrogen is detected mostly within the limits of the optical disc but also extends one and a half times the radius of the optical disk. The hydrogen forms streaming motions near the spiral arms.[6] The gas features two anticyclonic and four cyclonic vortices, rotating with the spiral pattern. The anticyclones are caused by the differential rotation and the cyclones are the result of a high amplitude in the density wave. The centres of the anticyclones are located between the observed spiral arms and the cyclones lie close to the observed spirals.[5]

NGC 3631 has weak diffuse X-ray emission.[7] There are six candidates ultraluminous X-ray sources in disk of the galaxy, two which have an optical counterpart.[8] The nucleus of the galaxy hosts a supermassive black hole with mass 107.4 (25 million), based on Ks bulge luminosity.[9]

Supernovae

Four supernovae have been discovered in NGC 3631: SN 1964A (mag. 17[10]), SN 1965L (mag. 15.95[11]), SN 1996bu, and SN 2016bau. SN 1996bu was a type II supernova discovered on November 14, 1996 and reached peak visual magnitude 17.3.[12] SN 2016bau was a type Ib supernova discovered before maximum light.[13] It was also observed in radio waves by the VLA as a radio source with a flux density of 1.0 ± 0.03 mJy at 8.6 GHz.[14]

Nearby galaxies

NGC 3631 forms a small group with NGC 3657,[15] which is part of the north Ursa Major groups, part of the Virgo Supercluster.[16]

Notes and References

  1. Web site: NASA/IPAC Extragalactic Database . Results for NGC 3631 . 2016-01-18 .
  2. http://cseligman.com/text/atlas/ngc36.htm#3631 NGC 3631
  3. Sandage, A., Bedke, J. (1994) The Carnegie Atlas of Galaxies. Volume I, Carnegie Institution of Washington
  4. Mineo. S.. Gilfanov. M.. Lehmer. B. D.. Morrison. G. E.. Sunyaev. R.. X-ray emission from star-forming galaxies – III. Calibration of the LX-SFR relation up to redshift z ≈ 1.3. Monthly Notices of the Royal Astronomical Society. 11 January 2014. 437. 2. 1698–1707. 10.1093/mnras/stt1999. free . 1207.2157. 2014MNRAS.437.1698M. 119190124.
  5. Fridman. A. M.. Khoruzhii. O. V.. Polyachenko. E. V.. Zasov. A. V.. Sil'Chenko. O. K.. Moiseev. A. V.. Burlak. A. N.. Afanasiev. V. L.. Dodonov. S. N.. Knapen. J. H.. Gas motions in the plane of the spiral galaxy NGC 3631. Monthly Notices of the Royal Astronomical Society. 21 May 2001. 323. 3. 651–662. 10.1046/j.1365-8711.2001.04218.x. free . astro-ph/0012116. 2001MNRAS.323..651F. 119517678 .
  6. Knapen. J. H.. Atomic hydrogen in the spiral galaxy NGC 3631. Monthly Notices of the Royal Astronomical Society. 1 April 1997. 286. 2. 403–414. 10.1093/mnras/286.2.403. free . astro-ph/9612137. 1997MNRAS.286..403K. 13901223.
  7. Mineo. S.. Gilfanov. M.. Sunyaev. R.. X-ray emission from star-forming galaxies - II. Hot interstellar medium. Monthly Notices of the Royal Astronomical Society. 1 November 2012. 426. 3. 1870–1883. 10.1111/j.1365-2966.2012.21831.x. free . 1205.3715. 2012MNRAS.426.1870M. 85507925.
  8. Smith. Beverly J.. Swartz. Douglas A.. Miller. Olivia. Burleson. Jacob A.. Nowak. Michael A.. Struck. Curtis. ChAInGeS: The Chandra Arp Interacting Galaxies Survey. The Astronomical Journal. 1 June 2012. 143. 6. 144. 10.1088/0004-6256/143/6/144. 1204.3194. 2012AJ....143..144S. 17427760.
  9. Dong. X. Y.. De Robertis. M. M.. Low-Luminosity Active Galaxies and Their Central Black Holes. The Astronomical Journal. March 2006. 131. 3. 1236–1252. 10.1086/499334. astro-ph/0510694. 2006AJ....131.1236D. 17630682.
  10. Web site: 1964A - The Open Supernova Catalog. sne.space. 2017-10-17. 2017-10-18. https://web.archive.org/web/20171018072709/https://sne.space/sne/1964A/. dead.
  11. Web site: 1965L - The Open Supernova Catalog. sne.space. 2017-10-17. 2017-10-18. https://web.archive.org/web/20171018072658/https://sne.space/sne/1965L/. dead.
  12. Web site: 1996bu - The Open Supernova Catalog. sne.space. 2017-10-17. 2017-10-18. https://web.archive.org/web/20171018072615/https://sne.space/sne/1996bu/. dead.
  13. Asiago spectroscopic and photometric observations of AT2016bau. The Astronomer's Telegram. 8818. 1. March 15, 2016. 2016ATel.8818....1G. Granata. V.. Benetti. S.. Cappellaro. E.. Elias-Rosa. N.. Pastorello. A.. Tomasella. L.. Nascimbeni. V.. Ochner. P.. Tartaglia. L.. Terreran. G.. Turatto. M..
  14. VLA observations of SN 2016bau of Type Ib in NGC 3631. The Astronomer's Telegram. 8911. 1. April 5, 2016. 2016ATel.8911....1K. Kamble. Atish. Margutti. Raffaella. Alexander. Kate. Berger. Edo. Cantiello. Matteo. Challis. Pete. Chomiuk. Laura. Guidorzi. Christiano. Kirshner. Robert. Milisavljevic. Danny. De Mink. Selma. Selma de Mink. Parrent. Jerod. Soderberg. Alicia. Alicia M. Soderberg. Zapartas. Emmanouil. Zauderer. Ashley.
  15. Makarov. Dmitry. Karachentsev. Igor. Galaxy groups and clouds in the local (z~ 0.01) Universe. Monthly Notices of the Royal Astronomical Society. 21 April 2011. 412. 4. 2498–2520. 10.1111/j.1365-2966.2010.18071.x. free . 2011MNRAS.412.2498M. 1011.6277. 119194025.
  16. Web site: The Ursa Major Groups. www.atlasoftheuniverse.com.