Galaxies IC 4633/5 with Integrated Flux Nebula
History
The galaxies IC 4633 and IC 4635 were discovered by DeLisle Stewart on a photo plate taken on 17 August 1900 at Harvard's Arequipa Station in Peru. For IC 4633 (= D.S. 437) he noted: «Very faint, considerably large, considerably brighter middle, possible spiral.» And for IC 4635 (= D.S. 438) he noted: «Very faint, extremely small, considerably brighter in the middle.» [364]
Physical Properties
IC 4633 is a galaxy, located approximately 100 million light-years away. It rich in star-forming activity, as well as hosting an active galactic nucleus. Together with IC 4635 and ESO 44-10 (LEDA/PGC 60085) they form a gravitationally bound triplet. These galaxies are partially concealed by a stretch of dark dust, which is part of the Chamaeleon star-forming region in our own galaxy, only 500 light-years away. The cloud overlapping IC 4633 lies east of the well-known Cha I, II and III, and has been called MW9 or the South Celestial Serpent. It is classified as an integrated flux nebula (IFN) — a cloud of gas and dust in the Milky Way galaxy that’s not near to any single star, and is only faintly lit by the total light of all the galaxy’s stars. [715]
| Name | RA | Dec | Type | bMag | vMag | B-V | SB | Dim | PA | z | D(z) | MD | Dreyer Description | Identification, Remarks |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| IC 4633 | 17 13 47.1 | -77 32 09 | Gx (Sc) | 13.7 | 13.0 | 0.7 | 15.5 | 4 × 3 | 145 | 0.009800 | 41.39 | 42.460 | vF, cL, cbM, ? spir | ESO 44-3; FAIR 841; AM 1705-773; IRAS 17062-7728 |
| IC 4635 | 17 15 40.4 | -77 29 21 | Gx (SBb) | 14.8 | 14.0 | 0.8 | 14.7 | 3 × 0.7 | 165 | 0.009833 | 41.53 | 32.700 | vF, eS, cbM | ESO 44-5; IRAS 17080-7725 |
Finder Chart
The two galaxies IC 4633 and IC 4635 can be found on the southern celestial hemisphere, near the southern pole in the unconspiciuous constellation Apus. Around 10 June it is in opposition to the sun and therefore culminates at local midnight.
