In A Galaxy, Very, Very Far Away...

Just, beyond a galaxy - far, far away....lie, two other galaxies, in a galaxy group that, the three - have all to themselves. The little group is called the "Leo Triplet" but it is actually likely part of a larger group of galaxies called the "Leo-I" ('Leo One') group.

Moreover, like most things 'cosmological', the connections don't end there: gas-streamer bridges connecting one galaxy or group of galaxies to another group - ultimately, ending in "super-clusters"; i.e., a cluster of clusters of galaxies - the largest, single structures in the universe!

The proximity of the Leo Triplet puts it roughly between our own "Local Group" of galaxies and the Leo-I group; "galaxy-group neighbors", so to speak - or numerically: only, around 30-35mly (million light-years) distant. How far away is that? Well, about 300 times the diameter of the Milky Way galaxy, which is ~120kly (~120,000ly), across.

The "Leo Triplet" consists of galaxies NGC 3628 (left), M65 (upper right), and M66 (lower right). Image provided by the author using Insight Observatory's 16" f/3.7 astrograph reflector, ATEO-1.

  
This tiny distant galaxy group features two spiral galaxies M-65 and M-66 discovered by French amateur astronomer Charles Messier; a comet-hunter by avocation. He tallied a list of small, dim objects in the night sky that appeared to be comets but he soon found we were not as they didn't move from their positions over long periods of time. They were permanent entities. He kept this list only to avoid these objects in future comet searches which he performed in the years around 1773.

The third galaxy, NGC-3628, another spiral saw edge-on; that is inclined 90° from our galactic perspective was discovered by German sister, and brother amateur astronomers William and Caroline Herschel back in the middle 1800s.

M-65, is a 'barless spiral, at 35mly. It is slightly warped, and, there has been some recent star birth activity in one of its gaseous H-II regions.

Of the three M-66 is closest at 31mly with a diameter of about 95kly. It is the brightest of the three but it is missing a large portion of one of its spiral arms. The missing mass from that arm was gravitationally removed by one or both of the other galaxies in the trio.

M-66, has a weak bar feature, extending from its core, and in this way is reminiscent of our own barred-spiral galaxy, the Milky Way. As of 2018 five supernovae have been observed in M-66: SN-2016cok, 2009hd, 1997bs, SN-1989B, and 1973R. SN-1989B was discovered independently by amateur astronomers Mike Petrasko and Dale Alan Bryant - one, cold, still morning in Feb of that same year.

Lastly, NGC-3628, the edge-on galaxy in this trio is also known as the "hamburger" galaxy. (Yes - it does indeed look like a "quarter-pounder" - viewed from the side!) Its disk spans 90tly and sits at 35mly away. The galaxy is composed mostly of older stars and like the other two is easily visible in amateur-class telescopes (4+ inches of aperture diameter). NGC-3628 also sports a 300tly-long, 'tidal tail', connecting the other two galaxies. It is the most distant of the three at 35mly. Its disk is around 100tly across.

Since there has been so much supernovae activity within at least one of the galaxies in this trio, I've decided it would be a good idea to begin an extra-galactic supernova search program using these three 'island universes.

So, here's the plan: take images of the three galaxies all within a single frame at some periodic interval (time series). Using an image of the three together that is known to be "supernova-free" - I can then compare subsequent images over time to the SN-free frame using a sort of 'blink comparator.

A blink-comparator is a device that was used frequently by astronomers to compare images of the same area of sky or objects within the same field of view of a telescope or camera over a specified interval. It involves the rapid sequencing back-and-forth of two images - one against the other. (In the distant, remote, ancient past - (*chuckle*: 1980's), I used two Kodak carousel slide projectors one stacked on the other projecting both slides at the same time onto a screen and then using a sheet of cardboard manually to alternately project the slide images one at a time in rapid succession onto the screen.

Currently, I'll use the two images in an animated, ".GIF", file, and "blink" them, that way. In this fashion, I can set the "blink" rate, and interval, for optimal comparison. In this way, any deviation from the standard field (used as a sort of, 'control group'), such as a blinking spot, line, or another anomaly, will stand out as extraneous data. This was how, Dr. Clyde W. Tombaugh, discovered the dwarf planet Pluto back in 1930. I'll be looking for any supernova activity within the three galaxies.

This is something that anyone using one of Insight Observatory's, remote telescopes can do on their own! It's a good way to involve oneself self in a Citizen Science project - of their own design!

I'll let you know if I find any action! -- you let me know what you find too!!

Dale Alan Bryant
Senior Contributing Science Writer

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Searching for Extragalactic Supernovae

I'll soon be doing an extragalactic supernova search, monitoring a small group of 5 or 6 spiral galaxies, similar in structure, to our Milky Way, barred-spiral galaxy - in the Virgo galaxy cluster.

The Virgo Cluster of galaxies is (around) 30-50 million light-years from the "Local Group" - the Milky Way's home, galactic cluster. The Virgo galactic cluster contains a spiral galaxy, M66, in the constellation Leo. It is some 35+ million light-years distant.

Back on 11 February 1989, at around 02:15am EST, Insight Observatory Managing Member and Project Developer, Michael Petrasko, and I, independently co-discovered a supernova (SN1989b), within one of the outer spiral arms of M66 (Michael, was the actual discoverer; I just "looked"!).

The Local Group and other galaxy cluster groups. Graphic by Dale Alan Bryant.

Supernova events within any given galaxy are estimated to occur only two or three times in a century. I'll see if I can refine that estimate, somewhat, over the course of a few months of nightly or bi-nightly photographic time-exposures of the group, using one of Insight Observatory's remote astrographs (photographic telescope) - ATEO-1, or ATEO-2A. The instruments are situated in the western New Mexico region, respectively - some of the clearest and darkest skies in the world.

Typically, an SN burst is so energetic that its brilliance, temporarily, outshines the combined light of all of the billions of stars within a given galaxy. Any SN event will stand out as a tiny, bright, dot, superimposed against the overall, dim, oval blur of light of the main body of the galaxy. It is during a supernova burst that the heavy elements of our universe are forged (iron, nickel, and other heavy metals). From there, the energy of the blast disperses the elemental metals into the surrounding space including any nearby molecular clouds which ultimately condense and become planetary systems (such was the case in our "Solar" system).

This is the history of the metallic content of Earth's mantle and crust, and, its solid iron core.

Dale Alan Bryant
Senior Contributing Science Writer

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M81 and M82 - "The Odd Couple"

Think of the perfect example of a "well-behaved", spiral galaxy, and M81 comes to mind, as, utter perfection. In the opposite direction, think of a galactic, "wild and crazy guy" - and it's M82. Now think of them, as a pair. Talk about an "Odd Couple"!

We are extremely fortunate to have this pair, as nearby as they are, at roughly, 12 light-years. The two, are members of the Ursa Major galactic cluster - a knot, in the Virgo Super-cluster of galaxies, as is our own, "Local Group", of galaxies.

M81, Bode's Galaxy (left), and M82, The Cigar Galaxy (right) in Ursa Major imaged on ATEO-1, the 16" f/3.7 astrograph reflector. Image data were acquired by Muir Evenden and processed by Utkarsh Mishra.

M81 and M82, are among the finest targets for the amateur astronomer with, even, a medium-sized telescope (6"-12"), their magnitude being, approximately, 7th, and 9th, respectively. But they can be detected in smaller scopes, and even, in a good pair of binoculars*, under good sky transparency conditions.

Let's separate the pair out for some analyses:

M81 is a type Sa spiral galaxy. It's, well - perfect. So much so, that it shares the distinctive title of, relatively few galaxies, as a "Grand Design Spiral". Now, that's something to boast about. And I do!

At a diameter of 90,000 light-years, and a distance of 12 million light-years, its relatively large size, and brightness, make it a "stunning" find in the eyepiece. In medium-sized scopes (12+"), the uniformity of its, "oh!-so-homogenous" spiral-arm structure, is notable.

And then, there was M82...

Well; if ever a galaxy looked like it was exploding - M82 - is it. In fact, for a very long time, that's just what astronomers thought was happening. However, there's a little more to it: what's really going on there, is, a massive outburst of star formation - to the point, that, in a sense it is "exploding" - with new stars! Our, Milky Way galaxy (BTW: a barred spiral, or, Sb-type), has a stellar generation rate of about 3, new stars, per year. M81's rate of star formation is something like 33 times that, of ours! (Whew!)

Because of the intense gravitational interaction between M81 and M82 - as well as, nearby, Ursa Major group member, NGC3077 - a small, disrupted, elliptical galaxy - both, M82 and NGC3077 are undergoing, intense, star formation periods in a very short span of time, as galaxies go. Tidal, and other, interruptions are causing large volumes of gases between the three galaxies, to fall inward, toward the cores of M82 and NGC3077. (M81 is, seemingly, immune to this sort of thing, of course!) But, all, three galaxies, are enveloped within interactive streams of gases. Both, M81 and M82, have hosted fairly recent supernovae activity; SN1993-J, in 1993 in M81 - and, SN2014-J, in 2014 in M82.

* Some, experienced, advanced amateurs have been able to detect both of these galaxies, under extremely good transparency conditions using only the unaided eye!

Dale Alan Bryant
Senior Contributing Science Writer

24 hours of Luminance, Red, Green, and Blue image data of M81 and M82 are available for download from Insight Observatory's deep-sky image repository, Starbase. 

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