Leo Triplet (M 65, M 66, NGC 3628)

Leo Triplet
Leo Triplet: NGC 3628 (left), M 65 (top right) and M 66 (bottom right); 8" Meade SC LX200, Shapley lens + Canon EOS 10D; 13 x 300s, 1600 ISO; Langis, Glaubenberg; © 8. 2. 2005 Niklaus J. Imfeld, Eduard von Bergen

History

The galaxies M 65 and M 66 were discovered by Charles Messier on 1 March 1780. He noted on M 65: «Nebula discovered in the Lion; It is very weak and does not contain a star.» And to M 66: «Nebula discovered in the lion; very weak light & very close to the previous one [M 65]: Both appear in the same field of the telescope. The comet observed in 1773 and 1774 passed between these two nebulae from November 1st to 2nd, 1773. M. Messier undoubtedly did not see them then because of the light of the comet.» Many attribute the discovery of the galaxies to Messier's friend Pierre Méchain, but since Messier usually explicitly mentions Méchain discoveries, but not here, it really seems Messier to be the discoverer. [4, 196, 217, 281]

NGC 3628, the fainter third galaxy of the Leo triplet, was only discovered by Wilhelm Herschel on 8 April 1784, when he observed Messier's discoveries. [196, 217]

M 65, M 66, NGC 3628
M 65, M 66, NGC 3628: Leo triplet in visible light (SDSS9, left, color adjusted) and in infrared (allWISE, right) [147]

Halton Arp, who examined the photographic plates of the «Palomar Observatory Sky Survey» (POSS) for strange galaxies, lists M 66 as Arp 16 and the entire Leo triplet as Arp 317 in his 1966 «Atlas of Peculiar Galaxies» also the designations APG 16 and APG 317. [199]

Physical Properties

The three galaxies M 65, M 66 and NGC 3628 show gravitational interactions with one another, which mainly influenced the appearance of M 66. The dusty spiral arms are slightly asymmetrical and contain many clusters of bright stars. A weak spiral arm on the north side seems to have already detached itself, which can be seen particularly well in the illustration of the «Sloan Digitized Sky Survey» in Fig. 2. At NGC 3628 we are looking exactly on the edge at a dense band of dust. [196]

The heliocentric speeds of the three galaxies, measured by spectral redshift, range from around 700 km/s to 850 km/s. The distances of the galaxy group determined with different methods (redshift, Cepheids, Tully-Fischer relation) amount to about 7.3 Mpc to 14.6 Mpc (24 to 48 million light years). [145]

Messier 65
Messier 65: Galaxy in Leo-Triplet; 500 mm Cassegrain 5800 mm f/11.4; SBIG STL11K; 10 min L; Bernese Highlands; © 2005 Radek Chromik
Messier 66
Messier 66: Galaxy in Leo-Triplet; 500 mm Cassegrain 5800 mm f/11.4; SBIG STL11K; 60+10+10+10 min LRGB; Bernese Highlands; © 2005 Radek Chromik
NGC 3628
NGC 3628: Hamburger-Galaxy in Leo-Triplet; 500 mm Cassegrain 3625 mm f/7.2; SBIG STL11K; 60+10+10+10 min LRGB; Bernese Highlands; © 2011 Radek Chromik
M 65 and M 66
M 65 and M 66: Galaxy pair in Leo-Triplet; 500 mm Cassegrain 3625 mm f/7.2; SBIG STL11K; 60+10+10+10 min LRGB; Bernese Highlands; © 2011 Radek Chromik
M 65 and M 66
M 65 and M 66: Galaxy pair in Leo-Triplet; RC 500 on AOK Herkules V48 mount; FLI Proline 16803; -30 °C chip temperature, R/G/B unbinned: R 19×10 min, G 20×10 min, B 25×10 min; Son Bi Observatory, Mallorca; © 20.-22. 6. 2017 Beat Kohler, Hansjörg Wälchli
Revised+Historic NGC/IC, Version 22/9, © Dr. Wolfgang Steinicke [277]
NameRADecTypebMagvMagDimDreyer DescriptionIdentification, Remarks
NGC 362311 18 55.6+13 05 27Gx (Sa)10.39.39.8 × 2.9B, vL, mE 165° ±, gbMBNM 65, UGC 6328, MCG 2-29-18, IRAS 11163+1322, CGCG 67-54, VV 308, Arp 317
NGC 362711 20 15.1+12 59 24Gx (Sb)9.78.99.1 × 4.1B, vL, mE 150°, mbM, 2 st npM 66, UGC 6346, MCG 2-29-19, Arp 16, CGCG 67-57, ARAK 288, VV 308, Arp 317
NGC 362811 20 16.7+13 35 24Gx (Sb)10.39.513.1 × 3.1pB, vL, vmE 102°UGC 6350, MCG 2-29-20, CGCG 67-58, Arp 317, VV 308, IRAS 11176+1351

Quasars around Galaxy NGC 3628

NGC 3628 + Quasare
NGC 3628 + Quasare: Galaxie NGC 3628 in Leo-Triplet mit Quasaren; Cassegrain 400 mm f/9, STL11000M + Canon EOS 20Da; L 75 min + RGB 60 min; Obwalden; © 2021 Eduard von Bergen

Scientific work on the galaxy NGC 3628 and the gas surrounding it brought some quasars to light. A closer look at the image of the galaxy NGC 3628 in the constellation of Leo reveals not only the X-ray flag but also very distant quasars. Five quasars with a light transit time of approx. 7.4 to 10.5 GLy with a corresponding redshift can be made out around the galaxy NGC 3628. The record in the picture is held by Quasar Wee 52 with a z of 2.43 or a large redshift. [395]

— 14. 6. 2021, Eduard von Bergen

Finder Chart

The galaxy group is located in the constellation Leo, roughly in the middle between the two stars Chertan (θ Leonis) and ι Leonis. The best observation time here is January to May.

Chart Leo Triplet (M 65, M 66, NGC 3628)
Leo Triplet (M 65, M 66, NGC 3628) in constellation Leo. Chart created using SkySafari 6 Pro and STScI Digitized Sky Survey. [149, 160]

Visual Observation

The two Messier galaxies M65 and M66 already show the first details in small instruments. However, it is interesting to look at the central dust band of the galaxy NGC3628 visible from the edge in middle telescopes. The photo in Fig. 1, obtained on an 8 "SC LX200 Meade telescope, roughly reproduces the visually visible richness of detail in a larger amateur telescope. [192]

— 8. 2. 2005 Eduard von Bergen

762 mm aperture: The visual impression can be reproduced with a MallinCam video camera and an integration time of around three seconds. A tracking 30" f/3.3 SlipStream Dobsonian was used. The resulting image comes very close to visual vision with a 13 mm Tele Vue Ethos eyepiece.

— 14. 3. 2012, Eduard von Bergen

Messier 65
Messier 65: EAA, roughly represents visual impression; 30" SlipStream Dobson f/3.3 + MallinCam Video camera; ca. 3s; Hasliberg; © 14. 3. 2012 Eduard von Bergen
Messier 66
Messier 66: EAA, roughly represents visual impression; 30" SlipStream Dobson f/3.3 + MallinCam Video camera; ca. 3s; Hasliberg; © 14. 3. 2012 Eduard von Bergen
NGC 3628
NGC 3628: EAA, roughly represents visual impression; 30" SlipStream Dobson f/3.3 + MallinCam Video camera; ca. 3s; Hasliberg; © 14. 3. 2012 Eduard von Bergen

More Objects Nearby (±15°)

References

4«Burnham's Celestial Handbook: An Observer's Guide to the Universe Beyond the Solar System» by Robert Burnham; Dover Publications, Inc.; Voume I: ISBN 0-486-23567-X; Volume II: ISBN 0-486-23568-8; Volume III: ISBN 0-486-23673-0
145SIMBAD astronomical database; simbad.u-strasbg.fr/simbad
147Aladin Lite; aladin.u-strasbg.fr/AladinLite (2020-12-23)
149SkySafari 6 Pro, Simulation Curriculum; skysafariastronomy.com
160The STScI Digitized Sky Survey; archive.stsci.edu/cgi-bin/dss_form
192Deep-Sky Guide; fernrohr.ch/1d_deep-sky-guide.html (2020-12-25)
196Celestial Atlas by Curtney Seligman; cseligman.com/text/atlas.htm (2020-12-28)
199«Atlas Of Peculiar Galaxies», Halton Arp, 1966; Astrophysical Journal Supplement, vol. 14, p.1 (1966); DOI:10.1086/190147; Bibcode:1966ApJS...14....1A
217The Messier Catalog (SEDS); messier.seds.org (2021-01-01)
277«Historische Deep-Sky Kataloge» von Dr. Wolfgang Steinicke; klima-luft.de/steinicke (2021-02-17)
281«Catalogue Nébuleuses et des Amas D'Étoiles» Observées à Paris, par M. Messier, à l'Observatoire de la Marine, hôtel de Clugni, rue des Mathurins. «Connoissance des temps ou connoissance des mouvements célestes, pour l'année bissextile 1784 » Page 227; gallica.bnf.fr/ark:/12148/bpt6k6514280n/f235 (2021-02-21)
395«NGC 3628: Ejection activity associated with quasars» H. Arp, E. M. Burbidge, Y. Chu, E. Flesch, F. Patat and G. Rupprecht; A&AVolume 391, Number 3, September I 2002, Pages 833 - 840; DOI:10.1051/0004-6361:20020828