NGC 2775

NGC 2775
NGC 2775 as taken by Hubble Space Telescope
Observation data (J2000 epoch)
ConstellationCancer
Right ascension09h 10m 20.112s[1]
Declination+07° 02′ 16.53″[1]
Redshift1,316.4±13.4 km/s[2]
Distance67 Mly (20.5 Mpc)[3]
Apparent magnitude (V)10.4[4]
Characteristics
TypeSAa[5] or SA(r)ab[6]
Apparent size (V)4.3′ × 3.3′[6]
Other designations
UGC 4820,[7] PGC 25861,[8] Caldwell 48
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NGC 2775, also known as Caldwell 48, is a spiral galaxy in the constellation Cancer. It is 67 million light-years (20.5 megaparsecs)[3] away from the Milky Way. It was discovered by William Herschel in 1783. NGC 2775 belongs to the Antlia-Hydra Cluster[9] of galaxies and is the most prominent member of the NGC 2775 Group, a small galaxy group in the Virgo Super-cluster, along with the Local Group. Other members of the NGC 2775 Group include NGC 2777 and UGC 4781.[10]

This object has a morphological classification of SA(r)ab,[6] which indicates an unbarred spiral galaxy (SA) with a prominent ring structure (r) and flocculent,[11] tightly wound spiral arms (ab).[12] The galaxy is inclined by an angle of 44° to the line of sight from the Earth.[6] The galactic nucleus is not active[2] and the large nuclear bulge, which extends out to an angular radius of 0.4′,[12] is relatively gas free.[11] An explanation for the latter could be a high supernova rate.[6] Although star formation is taking place in the dusty outer ring,[12] NGC 2775 does not display any current starburst activity,[13] and the galactic nucleus is virtually free of any star formation whatsoever.[11]

The galaxy's hydrogen tail feature indicates a past interaction with a faint companion.[6] A satellite galaxy appears to have orbited NGC 2775 multiple times, losing mass as it does so and creating faint, shell-like structures.[12] Nearby irregular galaxy NGC 2777 displays a tidal tail of hydrogen gas that points back to NGC 2775, suggesting the two may be linked.[14]

SN1993z is the only supernova known to have occurred in NGC 2775. It was detected on September 23, 1993, at a magnitude of 13.9, and was classified as a Type Ia supernova.[15] By September 25, spectral analysis showed that it had peaked four weeks earlier.[16]

  1. ^ a b Cite error: The named reference Skrutskie2006 was invoked but never defined (see the help page).
  2. ^ a b Cite error: The named reference Bosch2015 was invoked but never defined (see the help page).
  3. ^ a b Cite error: The named reference Cappellari2011 was invoked but never defined (see the help page).
  4. ^ Cite error: The named reference Finlay2006 was invoked but never defined (see the help page).
  5. ^ Cite error: The named reference Ann2015 was invoked but never defined (see the help page).
  6. ^ a b c d e f Cite error: The named reference Hogg2001 was invoked but never defined (see the help page).
  7. ^ Cite error: The named reference SIMBAD was invoked but never defined (see the help page).
  8. ^ Cite error: The named reference ned was invoked but never defined (see the help page).
  9. ^ Cite error: The named reference O'Meara2002 was invoked but never defined (see the help page).
  10. ^ Cite error: The named reference atlas was invoked but never defined (see the help page).
  11. ^ a b c Cite error: The named reference NASA2020 was invoked but never defined (see the help page).
  12. ^ a b c d Cite error: The named reference König2017 was invoked but never defined (see the help page).
  13. ^ Cite error: The named reference Shapiro2003 was invoked but never defined (see the help page).
  14. ^ Cite error: The named reference Arp1991 was invoked but never defined (see the help page).
  15. ^ Cite error: The named reference IAU1993 was invoked but never defined (see the help page).
  16. ^ Cite error: The named reference IAU5870 was invoked but never defined (see the help page).