NGC 6503
SAB:(s)bc[6]
EpochJ2000
Constellation nameDraco
Ra[1]
Dec[1]
Z0.000143[2]
H radial v28[3] km/s
Dist ly6.40 ± 0.66 Mpc[3]
Appmag v10.2[4]
Size v7.1 arcminute[5]
Names[2]

NGC 6503 is a field[7] dwarf spiral galaxy [dubious – discuss] in the northern constellation of Draco. It was discovered by German astronomer Arthur von Auwers on July 22, 1854.[4] The galaxy has an angular size of 7.1 arcminute[5] and an apparent visual magnitude of 10.2.[4] It is located at the distance of 18 million light years away from the Milky Way galaxy.[3] NGC 6503 may form the remote tip of a long chain of galaxies that extends out into the Local Void, forming a galaxy filament spanning 8 megaparsecs.[8]

The galactic plane of this galaxy is inclined at an angle of 78 ± 3 ° to the plane of the sky,[3] with the major axis of its oval profile being aligned along a position angle of 121°.[9] The morphological classification of NGC 6503 is SAB:(s)bc. This indicates a barred spiral galaxy (SAB:) with no inner ring structure (s) and moderately wound spiral arms (bc). However, the ':' notation indicates some uncertainty about the classification. Older works gave it a class of SA(s)bc; i.e. no bar.[6]

A possible bar system has been reported via infrared observations, being viewed end-on from the perspective of the Earth.[10][11] Ultraviolet observations show a young, inner star forming ring encircling the bar.[11] The ring has a radius between 1 and 2.5 kpc from the core.[12] There is a disk of neutral hydrogen that is larger in extent than the optical disk of the galaxy. This extra-planar gas is mostly the result of star formation activity, rather than cold gas that is being accreted.[13] There is evidence for a LINER-type or Seyfert 2 nucleus.[11]

NGC 6503 has one known satellite galaxy,[14] known as KK 242. With a stellar mass of about 3 million solar masses, KK 242 is on the border between a dwarf irregular galaxy (dIrr) and a dwarf spheroidal galaxy (dSph).[15]

References

  1. ^
  2. ^ "NGC 6503". Retrieved 2010-11-29.
  3. ^ Kourkchi, Ehsan et al. (October 23, 2020). "Cosmicflows-4: The Catalog of ∼10,000 Tully–Fisher Distances". The Astrophysical Journal. 902 (2): 145. arXiv:2009.00733. Bibcode:2020ApJ...902..145K. doi:10.3847/1538-4357/abb66b. ISSN 1538-4357
  4. ^ O'Meara, Stephen James (2007). Hidden Treasures. Cambridge University Press. p. 423. ISBN 978-1-139-46373-7.
  5. ^ Blanc, Guillermo A. et al. (2013). "The Virus-P Exploration of Nearby Galaxies (Venga): Survey Design, Data Processing, and Spectral Analysis Methods". The Astronomical Journal. 145 (5): 138. arXiv:1303.1552. Bibcode:2013AJ....145..138B. doi:10.1088/0004-6256/145/5/138. S2CID 119109864
  6. ^ Buta, Ronald J. et al. (2015). "A Classical Morphological Analysis of Galaxies in the Spitzer Survey of Stellar Structure in Galaxies (S4G)". The Astrophysical Journal Supplement Series. 217 (2): 32. arXiv:1501.00454. Bibcode:2015ApJS..217...32B. doi:10.1088/0067-0049/217/2/32. S2CID 119202943
  7. ^ Materne, J. (April 1979). "The structure of nearby groups of galaxies - Quantitative membership probabilities". Astronomy and Astrophysics. 74 (2): 235–243. Bibcode:1979A&A....74..235M
  8. ^ Karachentseva, Valentina E. et al. (October 2023). "The M 101 galaxy group as a node in a nearby cosmic filament". Astronomy & Astrophysics. 678: id. A16. arXiv:2308.01897. Bibcode:2023A&A...678A..16K. doi:10.1051/0004-6361/202347085
  9. ^ Bottema, Roelof & Gerritsen, Jeroen P. E. (October 1997). "An investigation of the structure and kinematics of the spiral galaxy NGC 6503". Monthly Notices of the Royal Astronomical Society. 290 (4): 585–597. arXiv:astro-ph/9704190. doi:10.1093/mnras/290.4.585
  10. ^ Kuzio de Naray, Rachel et al. (December 2012). "Searching for non-axisymmetries in NGC 6503: a weak end-on bar". Monthly Notices of the Royal Astronomical Society. 427 (3): 2523–2536. arXiv:1209.4653. Bibcode:2012MNRAS.427.2523K. doi:10.1111/j.1365-2966.2012.22126.x
  11. ^ Freeland, E.; Chomiuk, L.; Keenan, R.; Nelson, T. (March 2010). "Evidence for a Strong End-On Bar in the Ringed σ-Drop Galaxy NGC 6503". The Astronomical Journal. 139 (3): 865–870. arXiv:0912.0247. Bibcode:2010AJ....139..865F. doi:10.1088/0004-6256/139/3/865
  12. ^ Gouliermis, Dimitrios A. et al. (October 2015). "Hierarchical star formation across the ring galaxy NGC 6503". Monthly Notices of the Royal Astronomical Society. 452 (4): 3508–3528. arXiv:1506.03928. Bibcode:2015MNRAS.452.3508G. doi:10.1093/mnras/stv1325
  13. ^ Greisen, Eric W. et al. (June 2009). "Aperture Synthesis Observations of the Nearby Spiral NGC 6503: Modeling the Thin and Thick H I Disks". The Astronomical Journal. 137 (6): 4718–4733. arXiv:0902.0989. Bibcode:2009AJ....137.4718G. doi:10.1088/0004-6256/137/6/4718
  14. ^ Koda, Jin et al. (April 2015). "Discovery of New Dwarf Galaxy Near the Isolated Spiral Galaxy NGC 6503". The Astrophysical Journal Letters. 802 (2): id. L24. arXiv:1504.00674. Bibcode:2015ApJ...802L..24K. doi:10.1088/2041-8205/802/2/L24
  15. ^ Karachentsev, Igor D. et al. (2022). "KK 242, A Faint Companion to the Isolated SCD Galaxy NGC 6503". The Astronomical Journal. 163 (2): 51. arXiv:2111.14691. Bibcode:2022AJ....163...51K. doi:10.3847/1538-3881/ac3cbe. S2CID 244714422

Further reading