APOD: A View Toward M106 (2020 May 01)

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APOD: A View Toward M106 (2020 May 01)

Post by APOD Robot » Fri May 01, 2020 4:05 am

Image A View Toward M106

Explanation: Big, bright, beautiful spiral, Messier 106 dominates this cosmic vista. The nearly two degree wide telescopic field of view looks toward the well-trained constellation Canes Venatici, near the handle of the Big Dipper. Also known as NGC 4258, M106 is about 80,000 light-years across and 23.5 million light-years away, the largest member of the Canes II galaxy group. For a far far away galaxy, the distance to M106 is well-known in part because it can be directly measured by tracking this galaxy's remarkable maser, or microwave laser emission. Very rare but naturally occurring, the maser emission is produced by water molecules in molecular clouds orbiting its active galactic nucleus. Another prominent spiral galaxy on the scene, viewed nearly edge-on, is NGC 4217 below and right of M106. The distance to NGC 4217 is much less well-known, estimated to be about 60 million light-years, but the bright spiky stars are in the foreground, well inside our own Milky Way galaxy. Even the existence of galaxies beyond the Milky Way was questioned 100 years ago in astronomy's Great Debate.

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Re: APOD: A View Toward M106 (2020 May 01)

Post by Pit » Fri May 01, 2020 10:36 am

Wow, this is really a beatutiful shot!

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Re: APOD: A View Toward M106 (2020 May 01)

Post by orin stepanek » Fri May 01, 2020 12:53 pm

M106_ORG4_APOD1024c.jpg
There are those that say Earth is the only place where there is life! Why would there be so many galaxies; stars and planets if that were true? They are so far apart though!
8-) M106 and NGC 4217 very beautiful in this scene!
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Re: APOD: A View Toward M106 (2020 May 01)

Post by BDanielMayfield » Fri May 01, 2020 1:34 pm

This is truly a gorgeous APOD. What makes it so for me aren't mainly the galaxies however, it's the galaxies along with the three bright foreground stars and their awesome contrasting colors. Does anyone know the names of these stars?
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Re: APOD: A View Toward M106 (2020 May 01)

Post by rwlott » Fri May 01, 2020 1:51 pm

I'm curious about the faintly visible bluish galaxy at the right edge of the image, just right of the blue foreground star. Does this galaxy have a name/designation? Are there any larger images of it?

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Re: APOD: A View Toward M106 (2020 May 01)

Post by neufer » Fri May 01, 2020 2:28 pm

https://apod.nasa.gov/apod/astropix.html wrote:
<<M106 is about 80,000 light-years across and 23.5 million light-years away.>>
https://apod.nasa.gov/apod/ap130206.html wrote:
<<The well-measured distance to M106 is 23.5 million light-years,
making this [cropped] cosmic scene about 80,000 light-years across.>>
https://en.wikipedia.org/wiki/Messier_106 wrote:
<<Messier 106 is one of the largest and brightest nearby galaxies, similar in size [at 135,000 ly in diameter] and luminosity to the Andromeda Galaxy. It is at a distance of about 22 to 25 million light-years away from Earth.>>
Art Neuendorffer

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Re: APOD: A View Toward M106 (2020 May 01)

Post by johnnydeep » Fri May 01, 2020 5:39 pm

rwlott wrote:
Fri May 01, 2020 1:51 pm
I'm curious about the faintly visible bluish galaxy at the right edge of the image, just right of the blue foreground star. Does this galaxy have a name/designation? Are there any larger images of it?
Good eye! Don't know what that galaxy is, but there's another similar but fainter bluish one to the right and up from the bright foreground star near the bottom edge near the left side of the image.

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Re: APOD: A View Toward M106 (2020 May 01)

Post by johnnydeep » Fri May 01, 2020 6:16 pm

neufer wrote:
Fri May 01, 2020 2:28 pm
https://apod.nasa.gov/apod/astropix.html wrote:
<<M106 is about 80,000 light-years across and 23.5 million light-years away.>>
https://apod.nasa.gov/apod/ap130206.html wrote:
<<The well-measured distance to M106 is 23.5 million light-years,
making this [cropped] cosmic scene about 80,000 light-years across.>>
https://en.wikipedia.org/wiki/Messier_106 wrote:
<<Messier 106 is one of the largest and brightest nearby galaxies, similar in size [at 135,000 ly in diameter] and luminosity to the Andromeda Galaxy. It is at a distance of about 22 to 25 million light-years away from Earth.>>
Good observation of a conflict. Note 4 on the 135,000 ly figure from the wikipedia article points to https://freestarcharts.com/index.php/20 ... ral-galaxy, which confirms the 135,000 ly number, and also says that M106 is 19 arc minutes wide in the sky. At a distance of 23.5 Mly, that does in fact result in a diameter of about 130,000 ly: M106 diameter = 23.5e6 * 19 arc min / 3438(1) = 130,000 ly. I'm inclined to believe this result since the distance and width in the sky seem to be reliable.

(1) 3438 = 180 / pi * 60
Last edited by johnnydeep on Fri May 01, 2020 7:58 pm, edited 1 time in total.

palenoue

Re: APOD: A View Toward M106 (2020 May 01)

Post by palenoue » Fri May 01, 2020 6:28 pm

Why are those stars in the lower right corner so brightly colored?

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Re: APOD: A View Toward M106 (2020 May 01)

Post by johnnydeep » Fri May 01, 2020 7:29 pm

palenoue wrote:
Fri May 01, 2020 6:28 pm
Why are those stars in the lower right corner so brightly colored?
Probably image enhancement. The link to the author - https://blog.naver.com/omololee/221208161212 - run through google translate (https://translate.google.com/translate? ... 1208161212), reveals: "color adjustment, etc.: using Lightroom and Photoshop."

There's an almost identically framed picture at https://en.wikipedia.org/wiki/NGC_4217 that doesn't show the color differences so vividly.

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Re: APOD: A View Toward M106 (2020 May 01)

Post by Ann » Sat May 02, 2020 7:15 am

rwlott wrote:
Fri May 01, 2020 1:51 pm
I'm curious about the faintly visible bluish galaxy at the right edge of the image, just right of the blue foreground star. Does this galaxy have a name/designation? Are there any larger images of it?
Blue galaxy near blue star HD 106420 in M106 field Image Joonhwa Lee.png
Blue galaxy near blue star HD 106420 in M106 field Image Fabian Neyer.png
















A quick search turned up only one other picture of the blue galaxy you asked for, in an image by Fabian Neyer. My guess, for what it's worth, is that this tiny galaxy probably does have a designation, but I have no idea what it would be. The galaxy is very faint. How faint? Perhaps 16th magnitude? 17th?

Also note that while the little galaxy is blue in both images, its color is not as saturated or "deep" in Fabian Neyer's picture as it is in Joonhwa Lee's. We don't expect galaxies to be deeply blue in color. But this galaxy is definitely blue and therefore full of hot massive stars. Note that we can just barely make out a central bulge that appears bluish, but not as blue as the disk. There is an appreciable amount of old red stars in the bulge, but there are young stars there, too.

The blue disk "sticking out" from the bulge appears to be brightest at the ends. That is an interesting luminosity distribution.

Field of galaxies in Hercules around NGC 6050 Martin Pugh.png
Here is what I think might possibly be going on. Take a look at the image at right. It is a crop from an APOD by Ken Crawford (2014 June 25), and it shows a few galaxies in the Hercules Cluster of galaxies. At upper right, you can see the remarkable interacting trio NGC 6050/Arp 272 in an image by Hubble Legacy Archive/ Martin Pugh.

Below NGC 6050, you can see a blue ring galaxy. Actually, the ring is somewhat faint, but the bar inside the ring is bright. Can you see that the bar is bright blue at the ends?

At upper left, you can see a yellowish galaxy that is slightly similarly shaped, except it doesn't have a ring. It has a bright center, an elongated shape, and it is brighter at the ends of its disk (or bar?). So maybe the tiny blue galaxy in the APOD is actually a bright blue bar with a central yellowish bulge in the middle?



















The picture at left shows 11.3 magnitude galaxy NGC 4217 in a picture by Fabian Neyer. The small blue galaxy you asked about is located in the lower right corner. The picture at right shows 11.4 magnitude galaxy NGC 4424, and small 15.2 magnitude galaxy LEDA 213994. The small galaxy also has an IC designation, though: IC 3366.

So as you can see, the two larger galaxies in the two pictures are almost exactly equally bright, and there are two small edge-on background galaxies located close or relatively close to them in the sky. In my opinion, LEDA 213994/IC 3366 looks a lot brighter than the small blue galaxy you were asking for. So the blue galaxy is definitely not a 15th magnitude object. I don't think it's a 16th magnitude object either. So 17th magnitude? Maybe?

As you can see, IC 3366/LEDA 213994 appears to have a relatively bright surface brightness. It is also located where it might be moderately easy to spot, just at the visible edge of a relatively bright galaxy. By contrast, the small blue galaxy appears to have a lower surface brightness, and it is also smaller in size and located farther out in the "wilderness". It may have a designation, perhaps in the LEDA catalog, but I'm not inclined to look for it.

Let me say a few words about the foreground stars next to the small blue background galaxy in both Joonhwa Lee's and Fabian Neyer's images. The sharply blue-looking star really is quite blue as stars go. It is a star of spectral class B8, and it is much bluer than Sirius and Vega, and also bluer than Regulus or Alkaid at the end of the handle of the Big Dipper. It is bluer than any of the stars in the Pleiades. At a color index of -0.125, it is not as blue as the blue stars of Orion, but yes, it is blue. Eighth magnitude stars in the field of galaxies are rarely as blue as this.

As for the rather deeply orange star next to it, SAO 44089, it is a star of spectral class K5, and its B-V index is about +1.8. That is not as red as Betelgeuse, but yes, it is pretty red. So yes, these stars are colorful.

Ann
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GeoXXXXXX

Re: APOD: A View Toward M106 (2020 May 01)

Post by GeoXXXXXX » Sat May 02, 2020 11:03 am

rwlott wrote:
Fri May 01, 2020 1:51 pm
I'm curious about the faintly visible bluish galaxy at the right edge of the image, just right of the blue foreground star. Does this galaxy have a name/designation? Are there any larger images of it?
In the Principle Galaxies Catalogue it is designated PGC 2291939. Unfortunately I could locate no other data on it.

Eric

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Ann
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Re: APOD: A View Toward M106 (2020 May 01)

Post by Ann » Sat May 02, 2020 3:13 pm

GeoXXXXXX wrote:
Sat May 02, 2020 11:03 am
rwlott wrote:
Fri May 01, 2020 1:51 pm
I'm curious about the faintly visible bluish galaxy at the right edge of the image, just right of the blue foreground star. Does this galaxy have a name/designation? Are there any larger images of it?
In the Principle Galaxies Catalogue it is designated PGC 2291939. Unfortunately I could locate no other data on it.

Eric
Thanks for identifying the small blue galaxy, Eric!

You have undoubtedly checked the SIMBAD Astronomical Database to see if Simbad has any additional info on this tiny galaxy. But all Simbad offers us is the galaxy's PGC and LEDA designations, the galaxy's angular size, a small color picture of it and the correct coordinates for it. We are not even told what its magnitude is.

Ann
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GeoXXXXX

Re: APOD: A View Toward M106 (2020 May 01)

Post by GeoXXXXX » Sun May 03, 2020 11:59 am

Ann it’s quite frustrating isn’t it when you get curious about an object and there is just no info out there! I think the internet has spoiled us to where we now assume everything we could possibly want is just a mouse click away! :ssmile:

Eric