Editing Caelum (section)

=== Deep-sky objects ===
Due to its small size and location away from the plane of the [[Milky Way]], Caelum is rather devoid of deep-sky objects, and contains no [[Messier object]]s. The only [[deep-sky object]] in Caelum to receive much attention is [[HE0450-2958]], an unusual [[Seyfert galaxy]]. Originally, the jet's host galaxy proved elusive to find, and this jet appeared to be emanating from nothing.<ref name="Magain">{{Cite journal | last1 = Magain | first1 = P. | last2 = Letawe | first2 = G. R. | last3 = Courbin | first3 = F. D. R. | last4 = Jablonka | first4 = P. | last5 = Jahnke | first5 = K. | last6 = Meylan | first6 = G. | last7 = Wisotzki | first7 = L. | doi = 10.1038/nature04013 | title = Discovery of a bright quasar without a massive host galaxy | journal = Nature | volume = 437 | issue = 7057 | pages = 381–384 | year = 2005 | pmid =  16163349|arxiv = astro-ph/0509433 |bibcode = 2005Natur.437..381M | s2cid = 4303895 }}</ref> Although it has been suggested that the object is an ejected [[supermassive black hole]],<ref name="Hahenelt">{{Cite journal | last1 = Haehnelt | first1 = M. G. | last2 = Davies | first2 = M. B. | last3 = Rees | first3 = M. J. | title = Possible evidence for the ejection of a supermassive black hole from an ongoing merger of galaxies | doi = 10.1111/j.1745-3933.2005.00124.x | journal = Monthly Notices of the Royal Astronomical Society: Letters | volume = 366 | issue = 1 | pages = L22–L25 | year = 2006 | doi-access = free |arxiv = astro-ph/0511245 |bibcode = 2006MNRAS.366L..22H | s2cid = 18433710 }}</ref> the host is now agreed to be a small galaxy that is difficult to see due to light from the jet and a nearby [[starburst galaxy]].<ref name="Feain">{{Cite journal | last1 = Feain | first1 = I. J. | last2 = Papadopoulos | first2 = P. P. | last3 = Ekers | first3 = R. D. | last4 = Middelberg | first4 = E. | title = Dressing a Naked Quasar: Star Formation and Active Galactic Nucleus Feedback in HE 0450−2958 | doi = 10.1086/518027 | journal = The Astrophysical Journal | volume = 662 | issue = 2 | pages = 872 | year = 2007 |arxiv = astro-ph/0703101 |bibcode = 2007ApJ...662..872F | s2cid = 15556375 }}</ref>

The 13th magnitude [[planetary nebula]] PN G243-37.1 is also in the eastern regions of the constellation. It is one of only a few planetary nebulae found in the galactic halo, being {{val|20000|14000}} light-years below the Milky Way's 1000 light-year-thick disk.<ref>{{Cite Gaia DR2}}</ref>

Galaxies [[NGC 1595]], [[NGC 1598]], and the [[Carafe galaxy]] are known as the Carafe group. The Carafe galaxy is a Seyfert galaxy with ring. Its location is 4:28 / -47°54' (2000.0).<ref>Sky Catalogue 2000.0, Volume 2: Double Stars, Variable Stars and Nonstellar Objects (edited by Alan Hirshfeld and Roger W. Sinnott, 1985). Chapter 3: Glossary of Selected Astronomical Names.</ref><ref>Hugh C. Maddocks, Deep-Sky Name Index 2000.0 (Foxon-Maddocks Associates, 1991).</ref>