13 Giant Nearby Galaxies

[glenc]

“All bright galaxies within 20 million light years, including us, are organized in a ‘Local Sheet’ 34-million light years across and only 1.5-million light years thick,” says McCall. “The Milky Way and Andromeda are encircled by twelve large galaxies arranged in a ring about 24-million light years across – this ‘Council of Giants’ stands in gravitational judgment of the Local Group by restricting its range of influence.”
http://www.ras.org.uk/news-and-press...ncil-of-giants (http://www.ras.org.uk/news-and-press/news-archive/254-news-2014/2419-milky-way-amidst-a-council-of-giants)

The full text document is at
http://mnras.oxfordjournals.org/cont...8/mnras.stu199 (http://mnras.oxfordjournals.org/content/early/2014/02/28/mnras.stu199)
The 12 large nearby ‘Council of Giants’ galaxies are Cen A, NGC4945, M83, M64, M94, M81, M82, IC342, Maffei 1 & 2, NGC253 and Circinus.

[Weltevreden SA]

Yikes what a tour de force. Boggling reseach for a one-man paper. From the data I expected scads of co-authors and an army of MA interns beavering away anonymously in the physics library. This paper is sure to spawn a lot of re-examinations and additional detailed local studies. I hope globular, dwarf galaxy, and dark matter studies soon follow from other authors, as these will add a significant body of detail where it is most needed. I notice in Fig 3 that all the massive Gxx except for the MW-M31 group lie near the rim, making it more like a torus. There's also a pronounced binarism, most of it aligned radially to the Council's centre. I can't quite tell if the centre point in Fig 3 is the centre of mass or the volumetric centre; the text isn't specific. Mr. McCall doesn't say much about dark matter distribution—understandable considering all the rest of his detail. I wonder if the DM centre of mass is coincident with the Council's centre of mass or whether the DM distribution is clumpy. Looks to be clumpy. The centre of luminosity is a fair remove from the centre of the diagram; also an interesting anomaly counterintuitive to what one would expect. I would love to see detailed follow-ups about the 3D volumes of dwarf galaxies arrayed around the major groups, since the Local Group's dwarf structure is cylindrical rather than toroidal, and at a high incidence angle from the MW-M31 3d axis. The LG dwarfs additionally have significant mass distribution anomalies, with the dSphs lying within the DM tidal radius of the Local Groups and the dIrrs well outside. Dwarfs have roughly 10 times the DM mass per baryon mass than luminous galaxies. I sure hope Robert weighs in on this thread, as he eats this kind of paper for breakfast. Thanks again for bringing this to our attention, Glen.

I also notice with dismay the author's line in the Acknowledgments, "Particular gratitude is expressed to. . . whose attention to the author’s health allowed this work to be completed."

Hope for the best.

=Dana

[glenc]

An overview of the local galaxies
https://www.youtube.com/watch?feature=player_embedded&v=VzL7xGzfNlU
https://www.youtube.com/watch?v=VzL7xGzfNlU&feature=player_detailpage#t=61
and the music score
https://www.youtube.com/watch?v=ywEn5Ov5v7U&feature=player_detailpage

[Weltevreden SA]

Gee, Glen, my music sounds more like frogs and crickets. Sure wish my croaker cantata could upgrade to YouTube quality! =Dana

[glenc]

One of the 13 large nearby galaxies is mag 10.5 Circinus.
The attached image shows alpha and beta Centauri at the top with alpha Circinus below alp Cen and the Circinus galaxy 3.1 degrees to the right of alpha Cir.

[madbadgalaxyman]

I hope I can get a "Round Tuit" and look at McCall's paper. Unfortunately, all of my Tuits are square at the moment, as I happen to have got about 12 hrs per day of paid work for the following two months!

Lucky for McCall that he has access to a massive collection of existing data about the galaxies with 11 Mpc, the so called "Local Volume" Sample.
A sizeable part of this can be found in the Updated Nearby Galaxy Catalog:

http://heasarc.gsfc.nasa.gov/W3Browse/all/neargalcat.html

Also, the Local Volume galaxies have now been surveyed at many and various wavelengths (e.g. HI, Ha, near-infrared, UV, etc), so there is lots of data about.

Most of Marshall L. McCall's work revolves around the nearby galaxies. Not that he is one of the names who immediately comes to mind as one of the 'movers and shakers' of the field; perhaps because he doesn't publish frequently.
(other astronomers resort to putting their names on work which is done by vast multi-person teams or work that records only the most minute and tiny advance on existing knowledge. This is just like advertising.....the hope is that if you hear someone's name a lot, as co-author of hundreds of pathetic papers, the name will stick in your mind)

[glenc]

The 12 large nearby ‘Council of Giants’ galaxies are Cen A, NGC4945, M83, M64, M94, M81, M82, IC342, Maffei 1 & 2, NGC253 and Circinus.

I have seen 9 of these.
I have not seen IC342 and Maffei 1 & 2.

William Denning found IC342 in 1892 with a 10" reflector from Bristol, UK.
http://www.klima-luft.de/steinicke/ngcic/persons/denning.htm

Maffei 1 & 2 were named (http://en.wikipedia.org/wiki/Galaxies_named_after_people) after Paolo Maffei (http://en.wikipedia.org/wiki/Paolo_Maffei), who discovered them in 1967 via their infrared (http://en.wikipedia.org/wiki/Infrared_radiation) emissions.
Their wikisky org images are attached.

Page 23 of this document describes the discovery of Maffei 1 and 2.
http://sait.oat.ts.astro.it/MSAIt740103/Memsait2003_V74n1PDF/vol74n1p19.pdf
This link shows Two Micron All Sky Survey images of Maffei 1 & 2
http://www.ipac.caltech.edu/2mass/gallery/showcase/maffei/enlarged.html

Circinus is a spiral galaxy like our own Milky Way galaxy, located near the direction of the pointers to the southern cross constellation but 12 million light years away. The galaxy was discovered only in 1977 when Professor Ken Freeman at Mt Stromlo and Siding Spring Observatory noticed a smudge on a photographic plate. http://www.uq.edu.au/news/article/1998/06/scientists-discover-galactic-mystery
http://cdsads.u-strasbg.fr/abs/1977A%26A....55..445F

[madbadgalaxyman]

Thanks for these historical nuggets, Glen.

Our estimable IIS member, sjastro, has produced a really excellent Near infrared image of the Circinus Galaxy.

Here is a link to his image:
http://members.iinet.net.au/~sjastro/circinusnew.jpg (http://members.iinet.net.au/%7Esjastro/circinusnew.jpg)

[glenc]

Thanks Robert. That image is excellent.
I saw the core of Circinus this morning after the moon set at 5:10am.
I also saw N4945, N5128, M83 and M64, five of the 12 giants.

[glenc]

The Heart and Soul nebulae are seen in this infrared mosaic from NASA’s Wide-field Infrared Survey Explorer, or WISE.
Also visible near the bottom of this image are two galaxies, Maffei 1 and Maffei 2.
Maffei 1 is the bluish elliptical object (R) and Maffei 2 is the spiral galaxy (L). All four infra-red detectors aboard WISE were used to make this image.
Colour is representational: blue and cyan represent infra-red light at wavelengths of 3.4 and 4.6 microns, which is dominated by light from stars. Green and red represent light at 12 and 22 microns, which is mostly light from warm dust.
https://upload.wikimedia.org/wikiped...ul_nebulae.jpg (https://upload.wikimedia.org/wikipedia/commons/a/ad/Heart_and_Soul_nebulae.jpg)

[glenc]

The Local Giant Galaxies

http://mnras.oxfordjournals.org/content/early/2014/02/28/mnras.stu199/F3.large.jpg