Messier Index/M33

Triangulum Galaxy 300px Amateur photograph of the Triangulum Galaxy w:J2000 w:Triangulum SA(s)cd 01 33 50.9NASA/IPAC Extragalactic Database Results for NGC 598 http://nedwww.ipac.caltech.edu/ 2006-12-01 +30 39 36 6.27 NGC 0598, MCG +05-04-069, 1ES 0131+303, RX J0133.8+3039, PGC 005818 The Triangulum Galaxy (also known as Messier 33 or NGC 598) is a w:spiral galaxy approximately 3 million light-years away in the w:constellation w:Triangulum. The galaxy is also sometimes informally referred to as the Pinwheel Galaxy by some amateur astronomy referencesS. J. O'Meara 1998 The Messier Objects Cambridge University Cambridge 0-521-55332-6 and in some public outreach websites.NASA Spitzer Telescope Reveals Pinwheel Galaxy's Hidden Wonders http://www.spaceref.com/news/viewpr.html?pid=14321 2007-04-07 However, the w:SIMBAD Astronomical Database, a professional astronomy database that contains formal designations for astronomical objects, indicates that the name "Pinwheel Galaxy" is used to refer to w:Messier 101,SIMBAD Astronomical Database http://simbad.u-strasbg.fr/simbad/ Results for Messier 101. 2007-04-07 and several other amateur astronomy resources and other public outreach websites also identify Messier 101 by that name.Messier Object 101 http://www.seds.org/messier/m/m101.html 2007-04-07Best of AOP: M101: Pinwheel Galaxy http://simbad.u-strasbg.fr/simbad/ 2007-04-07 It is the third largest galaxy in the w:Local Group, a w:group of galaxies that also contains the w:Milky Way Galaxy and the w:Andromeda Galaxy, and it may be a gravitationally bound companion of the Andromeda Galaxy. The w:Pisces Dwarf (LGS 3), one of the small Local Group member galaxies, is possibly a w:satellite of Triangulum. General information left|thumb|170px|Triangulum (M33) and Andromeda (M31) The Triangulum Galaxy can be seen with the naked eye under exceptionally good conditions. While the fainter and more distant galaxy w:Messier 81 has also been seen with the naked eye by very experienced observers. However, some amateur astronomers may confuse the object with the nearby w:NGC 752, an w:open cluster that is brighter than the Triangulum Galaxy. October 2007 No known pre-telescopic observer notes it, which is not surprising: given its indistinctness, it is not likely to be noticed as an object unless one already knows of its existence. The Triangulum Galaxy was probably discovered by w:Giovanni Batista Hodierna before 1654, who may have grouped it together with w:open cluster NGC 752. It was independently discovered by w:Charles Messier in 1764, who catalogued it as M33 on August 25. M33 was also catalogued independently by w:William Herschel on September 11, 1784 number H V.17. It was among the first "w:spiral nebulae" identified as such by Lord Rosse. left|thumb|170px|w:NGC 604 in the Triangulum Galaxy Herschel also cataloged The Triangulum Galaxy's brightest and largest w:H II region (diffuse w:emission nebula containing w:ionized w:hydrogen) as H III.150 separately from the galaxy itself, which eventually obtained NGC number 604. As seen from Earth NGC 604 is located northeast of the galaxy's central core, and is one of the largest H II regions known with a diameter of nearly 1500 w:light-years and a spectrum similar to the w:Orion Nebula. Herschel also noted 3 other smaller H II regions (NGC 588, 592 and 595). In 2005, using observations of two water masers on opposite sides of Triangulum via the w:VLBA, researchers were, for the first time, able to estimate the angular rotation and proper motion of Triangulum. A velocity of 190 ± 60 km/s relative to the Milky Way is computed which means Triangulum is moving towards Andromeda.Brunthaler, Andreas; Reid, Mark J.; Falcke, Heino; Greenhill, Lincoln J.; Henkel, Christian 2005 The Geometric Distance and Proper Motion of the Triangulum Galaxy (M33) Science 307 5714 1440–1443 http://adsabs.harvard.edu/cgi-bin/nph-bib_query?bibcode=2005Sci...307.1440B 10.1126/science.1108342 15746420 In 2007, a black hole about 15.7 times the mass of the Sun was detected in the galaxy using data from the w:Chandra X-ray Observatory. The black hole, named M33 X-7, orbits a companion star which it eclipses every 3.5 days.Morcone, Jennifer, Heaviest Stellar Black Hole Discovered in Nearby Galaxy, w:Chandra X-ray Observatory press release, 2007-10-17 mdy The galaxy has an H II nucleus. Ho Luis C. Filippenko Alexei V. Sargent Wallace L. W. A Search for "Dwarf" Seyfert Nuclei. III. Spectroscopic Parameters and Properties of the Host Galaxies 1997 October 1997 Astrophysical Journal Supplement 112 315–390 http://adsabs.harvard.edu/cgi-bin/nph-bib_query?bibcode=1997ApJS..112..315H 10.1086/313041 Ho, Luis C. The Astrophysical Journal Supplement Series Distance At least three techniques have been used to measure distances to M 33. Using the w:Cepheid variable method, an estimate of 2.77 ± 0.13 Mly (850 ± 40 kpc) was achieved in 2004.I. D. Karachentsev, V. E. Karachentseva, W. K. Hutchmeier, D. I. Makarov A Catalog of Neighboring Galaxies Astronomical Journal 2004 127 2031–2068 http://adsabs.harvard.edu/abs/2004AJ....127.2031K 10.1086/382905Karachentsev, I. D.; Kashibadze, O. G. Masses of the local group and of the M81 group estimated from distortions in the local velocity field Astrophysics 2006 49 1 3–18 http://adsabs.harvard.edu/cgi-bin/nph-bib_query?bibcode=2006Ap.....49....3K 10.1007/s10511-006-0002-6 Also 2004, the w:Tip of the Red Giant Branch (TRGB) method was used to derive a distance estimate of 2.59 ± 0.08 Mly (794 ± 23 kpc). http://adsabs.harvard.edu/abs/2004MNRAS.350..243M Determining the location of the tip of the red giant branch in old stellar populations: M33, Andromeda I and II 2004 May 2004 Monthly Notices of the Royal Astronomical Society 350 1 250 10.1111/j.1365-2966.2004.07637.x McConnachie, A. W.; Irwin, M. J.; Ferguson, A. M. N.; Ibata, R. A.; Lewis, G. F.; Tanvir, N. In 2006, a group of astronomers announced the discovery of an eclipsing binary star in the Triangulum Galaxy. By studying the eclipses of the stars, the astronomers were able to measure their sizes. Knowing the sizes and temperatures of the stars they were able to measure the w:absolute magnitude of the stars. When the visual and absolute magnitudes are known, the distance to the star can be measured. The stars lie at the distance of 3.1 ± 0.2 Mly (940 ± 70 kpc).Bonanos, A. Z.; Stanek, K. Z.; Kudritzki, R. P.; Macri, L.; Sasselov, D. D.; Kaluzny, J.; Bersier, D.; Bresolin, F.; Matheson, T.; Mochejska, B. J.; Przybilla, N.; Szentgyorgyi, A. H.; Tonry, J.; Torres, G. 2006 The First DIRECT Distance to a Detached Eclipsing Binary in M33 Astrophysics and Space Science Online First 207 http://adsabs.harvard.edu/cgi-bin/nph-bib_query?doi=10.1007%2Fs10509-006-9112-1 10.1007/s10509-006-9112-1 average(850 ± 40, 794 ± 23, 940 ± 70) = ((850 + 794 + 940) / 3) ± ((40² + 23² + 70²)0.5 / 3) = 861 ± 28 Averaged together, all these distance measurements give a combined distance estimate of 2.81 ± 0.09 Mly (861 ± 28 kpc). References in fiction Galaxies in fiction In the episode "w:Where No One Has Gone Before" of the first season of w:Star Trek: The Next Generation, the Enterprise is hurled into the far side of M33 by an alien visitor known only as "The Traveler". In the TV series Andromeda, Triangulum Galaxy is one of the three galaxies forming the Systems Commonwealth, along with The Milky Way and Andromeda. In the 2007 computer game w:Crysis, the alien antagonists of the game are said to have originated from the galaxy M33. In the comic-book series w:Yoko Tsuno, the Vineans originated from M33, with the first mention of it being in the sixth album w:Les Trois soleils de Vinéa (The Three Suns of Vinea). References 2 External links Messier 33, SEDS Messier pages M33 at ESA/Hubble Triangulum Galaxy High In Northern Skies