APOD: NGC 2442: Galaxy in Volans (2020 Aug 04)

Comments and questions about the APOD on the main view screen.
User avatar
APOD Robot
Otto Posterman
Posts: 4076
Joined: Fri Dec 04, 2009 3:27 am

APOD: NGC 2442: Galaxy in Volans (2020 Aug 04)

Post by APOD Robot » Tue Aug 04, 2020 4:06 am

Image NGC 2442: Galaxy in Volans

Explanation: Distorted galaxy NGC 2442 can be found in the southern constellation of the flying fish, (Piscis) Volans. Located about 50 million light-years away, the galaxy's two spiral arms extending from a pronounced central bar have a hook-like appearance in wide-field images. But this mosaicked close-up, constructed from Hubble Space Telescope and European Southern Observatory data, follows the galaxy's structure in amazing detail. Obscuring dust lanes, young blue star clusters and reddish star forming regions surround a core of yellowish light from an older population of stars. The sharp image data also reveal more distant background galaxies seen right through NGC 2442's star clusters and nebulae. The image spans about 75,000 light-years at the estimated distance of NGC 2442.

<< Previous APOD This Day in APOD Next APOD >>

User avatar
geckzilla
Ocular Digitator
Posts: 9133
Joined: Wed Sep 12, 2007 12:42 pm
Location: Modesto, CA

Re: APOD: NGC 2442: Galaxy in Volans (2020 Aug 04)

Post by geckzilla » Tue Aug 04, 2020 4:41 am

Huh, this galaxy has a common name: The Meathook. Guess it's too evocative for APOD.
Just call me "geck" because "zilla" is like a last name.

User avatar
Ann
4725 Å
Posts: 10820
Joined: Sat May 29, 2010 5:33 am

Re: APOD: NGC 2442: Galaxy in Volans (2020 Aug 04)

Post by Ann » Tue Aug 04, 2020 5:25 am

I'm so glad to see such a splendid picture of this spectacular galaxy become an APOD! Thank you, NASA/Hubble, ESO, Robert Gendler and Roberto Colombari! (And thank you, Robert Nemiroff!) :D


An aside: NGC 2442 is clearly chock full of star formation. Nevertheless, the galaxy's B-V and U-B indexes are not all that impressively blue. Obviously the reason for this relative lack of cerulean-ness is due to the high dust content of NGC 2442. I tried to find out the far infrared magnitude of "The Meathook", because a comparison between the B (blue) and the far infrared magnitude would have told us if this galaxy is indeed very dusty.

Well, never mind whether the far infrared magnitude of NGC 2442 has been officially measured. We can tell at a glance that this galaxy is full of dust!

Ann
Color Commentator

A vent

Re: APOD: NGC 2442: Galaxy in Volans (2020 Aug 04)

Post by A vent » Tue Aug 04, 2020 5:34 am

At what point do we start using hieroglyphics again? Grammar in any language is important. Nice post, just not proof read, if I had to say

Boomer12k
:---[===] *
Posts: 2691
Joined: Sun Apr 22, 2007 12:07 am

Re: APOD: NGC 2442: Galaxy in Volans (2020 Aug 04)

Post by Boomer12k » Tue Aug 04, 2020 8:54 am

Looking at wide angle shots it does not seem to be reacting with any other close galaxy... so I am thinking there was a merger...there is a very bright area in the right side of the bar... I am wondering if that is where the other nucleus is... or maybe there was a satellite galaxy and that caused some disruption as it fell inward...

:---[===] *

User avatar
orin stepanek
Plutopian
Posts: 5766
Joined: Wed Jul 27, 2005 3:41 pm
Location: Nebraska

Re: APOD: NGC 2442: Galaxy in Volans (2020 Aug 04)

Post by orin stepanek » Tue Aug 04, 2020 10:24 am

NGC2442_HstGendler_960.jpg

Meathook Galaxy! I like that Judy! 🤩
You do not have the required permissions to view the files attached to this post.
Orin

Smile today; tomorrow's another day!

XgeoX
Ensign
Posts: 35
Joined: Tue Jun 30, 2020 12:57 pm
AKA: Idiot

Re: APOD: NGC 2442: Galaxy in Volans (2020 Aug 04)

Post by XgeoX » Tue Aug 04, 2020 11:05 am

A vent wrote:
Tue Aug 04, 2020 5:34 am
At what point do we start using hieroglyphics again? Grammar in any language is important. Nice post, just not proof read, if I had to say
Well hieroglyphic languages had grammar rules as well but I have to point out you left out the period at the end of your post! 😼

Eric

XgeoX
Ensign
Posts: 35
Joined: Tue Jun 30, 2020 12:57 pm
AKA: Idiot

Re: APOD: NGC 2442: Galaxy in Volans (2020 Aug 04)

Post by XgeoX » Tue Aug 04, 2020 11:26 am

I like how the little galaxy in the upper “hook” of 2442 looks very similar but hooks in the opposite direction.

Eric

User avatar
orin stepanek
Plutopian
Posts: 5766
Joined: Wed Jul 27, 2005 3:41 pm
Location: Nebraska

Re: APOD: NGC 2442: Galaxy in Volans (2020 Aug 04)

Post by orin stepanek » Tue Aug 04, 2020 12:08 pm

th.jpg

Or maybe the Seahorse Galaxy!!!!! :yes: :D
You do not have the required permissions to view the files attached to this post.
Orin

Smile today; tomorrow's another day!

User avatar
neufer
Vacationer at Tralfamadore
Posts: 17521
Joined: Mon Jan 21, 2008 1:57 pm
Location: Alexandria, Virginia

Re: APOD: NGC 2442: Galaxy in Volans (2020 Aug 04)

Post by neufer » Tue Aug 04, 2020 2:59 pm

geckzilla wrote:
Tue Aug 04, 2020 4:41 am

Huh, this galaxy has a common name: The Meathook. Guess it's too evocative for APOD.
https://en.wikipedia.org/wiki/Yesterday_and_Today wrote:

<<Yesterday and Today was the Beatles ninth album issued on Capitol Records and twelfth American release overall. It is remembered primarily for the controversy surrounding its original cover image. Known as the "butcher cover", it was taken by photographer Robert Whitaker and shows the band dressed in white coats and covered with decapitated baby dolls and pieces of raw meat. Although the photo was intended to be part of a larger work critiquing the adulation afforded the Beatles, the band members insisted it was a statement against the Vietnam War. Others interpreted it as the Beatles protesting the record company's policy of "butchering" their albums for the North American market. In response to outrage from record retailers, the LP was withdrawn and the cover replaced with a shot of the band posed around a steam trunk.

The album's title plays on that of the song "Yesterday". The original LP became a highly prized item among collectors. Since some of Capitol's pressing plants merely pasted the trunk image onto the existing LP covers, the album also encouraged a phenomenon of stripping back the top layer of artwork in the search for a banned butcher cover. Having been deleted from Capitol's catalogue in 1986, Yesterday and Today was reissued on CD in 2014.>>
https://en.wikipedia.org/wiki/Volans wrote:


<<Volans is a constellation in the southern sky. It represents a flying fish; its name is a shortened form of its original name, Piscis Volans. Volans was one of twelve constellations created by Petrus Plancius from the observations of Pieter Dirkszoon Keyser and Frederick de Houtman and it first appeared on a 35-cm diameter celestial globe published in 1597 (or 1598) in Amsterdam by Plancius with Jodocus Hondius. Plancius called the constellation Vliegendenvis (flying fish).

In 1603, Johann Bayer included the constellation in his star atlas Uranometria under the name Piscis Volans, the flying fish. John Herschel proposed shrinking the name to one word in 1844, noting that Lacaille himself had abbreviated his constellations thus on occasion. This was universally adopted. Volans represents a type of tropical fish that can jump out of the water and glide through the air on wings. In early celestial maps, the flying fish was often depicted as accompanying the ship Argo Navis, and being chased by the predatory fish represented by the adjoining constellation Dorado.>>
Art Neuendorffer

BDanielMayfield
Don't bring me down
Posts: 2495
Joined: Thu Aug 02, 2012 11:24 am
AKA: Bruce
Location: East Idaho

Re: APOD: NGC 2442: Galaxy in Volans (2020 Aug 04)

Post by BDanielMayfield » Tue Aug 04, 2020 3:22 pm

Boomer12k wrote:
Tue Aug 04, 2020 8:54 am
Looking at wide angle shots it does not seem to be reacting with any other close galaxy... so I am thinking there was a merger...there is a very bright area in the right side of the bar... I am wondering if that is where the other nucleus is... or maybe there was a satellite galaxy and that caused some disruption as it fell inward...

:---[===] *
The first thing I also did after seeing this APOD was look for the other galaxy. I came to the first idea Boomer expressed. Clearly NGC 2442 is a very distorted spiral, so something massive must have caused all this distortion. I suggest as he did that the core of the second galaxy is the large bright blob behind the southern arm of NGC 2442's sharply curving dust band, and that some of the dim white star field mostly above that arm could be a tidal stream of stars pulled from the second galaxy.

Bruce
Just as zero is not equal to infinity, everything coming from nothing is illogical.

User avatar
johnnydeep
Science Officer
Posts: 247
Joined: Sun Feb 20, 2011 8:57 pm

Re: APOD: NGC 2442: Galaxy in Volans (2020 Aug 04)

Post by johnnydeep » Tue Aug 04, 2020 4:11 pm

APOD Robot wrote:
Tue Aug 04, 2020 4:06 am
Image NGC 2442: Galaxy in Volans

Explanation: Distorted galaxy NGC 2442 can be found in the southern constellation of the flying fish, (Piscis) Volans. Located about 50 million light-years away, the galaxy's two spiral arms extending from a pronounced central bar have a hook-like appearance in wide-field images. But this mosaicked close-up, constructed from Hubble Space Telescope and European Southern Observatory data, follows the galaxy's structure in amazing detail. Obscuring dust lanes, young blue star clusters and reddish star forming regions surround a core of yellowish light from an older population of stars. The sharp image data also reveal more distant background galaxies seen right through NGC 2442's star clusters and nebulae. The image spans about 75,000 light-years at the estimated distance of NGC 2442.
So how many background galaxies can we find? I've got 4 so far:
InkedNGC2442_HstGendler_2400_LI_small.jpg
You do not have the required permissions to view the files attached to this post.
"To Boldly Go......Beyond The Fields We Know."

User avatar
Ann
4725 Å
Posts: 10820
Joined: Sat May 29, 2010 5:33 am

Re: APOD: NGC 2442: Galaxy in Volans (2020 Aug 04)

Post by Ann » Tue Aug 04, 2020 5:39 pm

BDanielMayfield wrote:
Tue Aug 04, 2020 3:22 pm
Boomer12k wrote:
Tue Aug 04, 2020 8:54 am
Looking at wide angle shots it does not seem to be reacting with any other close galaxy... so I am thinking there was a merger...there is a very bright area in the right side of the bar... I am wondering if that is where the other nucleus is... or maybe there was a satellite galaxy and that caused some disruption as it fell inward...

:---[===] *
The first thing I also did after seeing this APOD was look for the other galaxy. I came to the first idea Boomer expressed. Clearly NGC 2442 is a very distorted spiral, so something massive must have caused all this distortion. I suggest as he did that the core of the second galaxy is the large bright blob behind the southern arm of NGC 2442's sharply curving dust band, and that some of the dim white star field mostly above that arm could be a tidal stream of stars pulled from the second galaxy.

Bruce
I don't get that, Bruce, and I don't see any sign of a second nucleus. What large bright blob is "behind" the southern arm of NGC 2442's sharply curving dust band?

And where do you see a rather dim "white" star field?

Tadpole galaxy with intruder galaxy.png
Let's compare NGC 2442 with the Tadpole Galaxy. This is what NASA wrote about their picture of the Tadpole Galaxy, also known as Arp 188:
NASA wrote:

Scientists believe that a more compact intruder galaxy crossed in front of Arp 188 - from left to right in this view - and was slung around behind the Tadpole via gravitational attraction. During the close encounter, tidal forces drew out the galaxy's stars, gas, and dust forming the spectacular tail. The intruder galaxy itself, estimated to lie about 300 thousand light-years behind the Tadpole, can be seen through foreground spiral arms at the upper left.
NGC 2442 by ESO with possible intruder.png



I really can't say that I can see anything similar in NGC 2442, with the possible, possible exception of the blob that I have marked with a ring. (Or possibly, possibly the even smoother blob to the left of the feature I have marked, immediately to the right of the dust lane in the upper arm?)

The photo of NGC 2442 at right is the original ESO image that Robert Gendler and Roberto Colombari used (along with Hubble space data) when they processed the image that became today's APOD.

Did you think of this feature when you talked about an intruder galaxy, or did you refer to another feature in NGC 2442?

Ann
You do not have the required permissions to view the files attached to this post.
Color Commentator

BDanielMayfield
Don't bring me down
Posts: 2495
Joined: Thu Aug 02, 2012 11:24 am
AKA: Bruce
Location: East Idaho

Re: APOD: NGC 2442: Galaxy in Volans (2020 Aug 04)

Post by BDanielMayfield » Tue Aug 04, 2020 7:02 pm

Ann wrote:
Tue Aug 04, 2020 5:39 pm
BDanielMayfield wrote:
Tue Aug 04, 2020 3:22 pm
Boomer12k wrote:
Tue Aug 04, 2020 8:54 am
Looking at wide angle shots it does not seem to be reacting with any other close galaxy... so I am thinking there was a merger...there is a very bright area in the right side of the bar... I am wondering if that is where the other nucleus is... or maybe there was a satellite galaxy and that caused some disruption as it fell inward...

:---[===] *
The first thing I also did after seeing this APOD was look for the other galaxy. I came to the first idea Boomer expressed. Clearly NGC 2442 is a very distorted spiral, so something massive must have caused all this distortion. I suggest as he did that the core of the second galaxy is the large bright blob behind the southern arm of NGC 2442's sharply curving dust band, and that some of the dim white star field mostly above that arm could be a tidal stream of stars pulled from the second galaxy.

Bruce
I don't get that, Bruce, and I don't see any sign of a second nucleus. What large bright blob is "behind" the southern arm of NGC 2442's sharply curving dust band?

And where do you see a rather dim "white" star field?

Tadpole galaxy with intruder galaxy.png
Let's compare NGC 2442 with the Tadpole Galaxy. This is what NASA wrote about their picture of the Tadpole Galaxy, also known as Arp 188:
NASA wrote:

Scientists believe that a more compact intruder galaxy crossed in front of Arp 188 - from left to right in this view - and was slung around behind the Tadpole via gravitational attraction. During the close encounter, tidal forces drew out the galaxy's stars, gas, and dust forming the spectacular tail. The intruder galaxy itself, estimated to lie about 300 thousand light-years behind the Tadpole, can be seen through foreground spiral arms at the upper left.
NGC 2442 by ESO with possible intruder.png



I really can't say that I can see anything similar in NGC 2442, with the possible, possible exception of the blob that I have marked with a ring. (Or possibly, possibly the even smoother blob to the left of the feature I have marked, immediately to the right of the dust lane in the upper arm?)

The photo of NGC 2442 at right is the original ESO image that Robert Gendler and Roberto Colombari used (along with Hubble space data) when they processed the image that became today's APOD.

Did you think of this feature when you talked about an intruder galaxy, or did you refer to another feature in NGC 2442?

Ann
No. To find the bright white blob that Boomer and I think might be the core of a second interacting galaxy draw a line from your green circle though the center of the main galaxy and continue down about the same distance to the bottom edge of your cropped image. (Your image has cropped off most of it.) This 'blob' is much larger than what you circled, and it is crossed by the dust band of the larger galaxy's lower spiral arm. In fact this blob of white starlight is larger than the yellower extended core of the main galaxy. The shape of this blob is very elliptical. It could even be an Elliptical galaxy with zero star formation going on. A possible dim white tidal tail of stars from this proposed intruder could be behind and mostly above the main lower arm.

That's all 3D speculation based on a 2D snapshot though. What's really needed is a view from Andromeda and/or Triangulum! :lol2:
Just as zero is not equal to infinity, everything coming from nothing is illogical.

User avatar
Ann
4725 Å
Posts: 10820
Joined: Sat May 29, 2010 5:33 am

Re: APOD: NGC 2442: Galaxy in Volans (2020 Aug 04)

Post by Ann » Tue Aug 04, 2020 8:19 pm

BDanielMayfield wrote:
Tue Aug 04, 2020 7:02 pm

No. To find the bright white blob that Boomer and I think might be the core of a second interacting galaxy draw a line from your green circle though the center of the main galaxy and continue down about the same distance to the bottom edge of your cropped image. (Your image has cropped off most of it.) This 'blob' is much larger than what you circled, and it is crossed by the dust band of the larger galaxy's lower spiral arm. In fact this blob of white starlight is larger than the yellower extended core of the main galaxy. The shape of this blob is very elliptical. It could even be an Elliptical galaxy with zero star formation going on. A possible dim white tidal tail of stars from this proposed intruder could be behind and mostly above the main lower arm.

That's all 3D speculation based on a 2D snapshot though. What's really needed is a view from Andromeda and/or Triangulum! :lol2:
I see what you mean, Bruce, but I don't agree.

Past star formation in NGC 2442 with arrow.png
NGC 5395 in the Heron Galaxy with arrow.png

The diffuse white "arc" that smoothly follows the bend of the spiral arm of NGC 2442 is the remnant of extremely vigorous star formation in this spiral arm in the past. Compare the white arc of NGC 2442 with the very similar (but even more extreme) white arc in galaxy NGC 5395.

Take a look at the picture at right of M51, and take a good look at the spiral arm near the bottom of the image.

You can see that red emission nebulas surrounding massive hot newborn stars of spectral class O and B have been born typically near the outer edge of the massive dark dust lane of this spiral arm. But note that outside this line of red emission nebulas, we can see scattered supergiant stars of different colors set against a relatively smooth background of bluish stars of (I'd say) late B, A and F-type stars, mixed with a huge number of fainter stars of spectral class G (and still more still fainter stars that are even cooler).

Note that this "outer arc" of stars follows the shape of the inner, starforming dust lane perfectly. Note that the color of it is much less blue than the bluest, youngest stars in the bright star clusters, but it is much bluer than the brownish "inter-arm" regions near the center of the galaxy.

This is the remnant of vigorous star formation in the past. The brightest, hottest products of that burst of star formation have died since then, and cooler, less blue and ultraviolet stars remain. In time, this remnant of vigorous star formation will grow ever less blue and also (over time) fainter.

So, in short, that white arc in NGC 2442 is the remnant of past star formation and not the remnant of another galaxy.

Ann
You do not have the required permissions to view the files attached to this post.
Color Commentator

BDanielMayfield
Don't bring me down
Posts: 2495
Joined: Thu Aug 02, 2012 11:24 am
AKA: Bruce
Location: East Idaho

Re: APOD: NGC 2442: Galaxy in Volans (2020 Aug 04)

Post by BDanielMayfield » Tue Aug 04, 2020 9:12 pm

I follow your well explained points Ann. You are very likely correct.
Just as zero is not equal to infinity, everything coming from nothing is illogical.

User avatar
neufer
Vacationer at Tralfamadore
Posts: 17521
Joined: Mon Jan 21, 2008 1:57 pm
Location: Alexandria, Virginia

Re: APOD: NGC 2442: Galaxy in Valens (2020 Aug 04)

Post by neufer » Wed Aug 05, 2020 2:56 am

Click to play embedded YouTube video.

Last edited by neufer on Wed Aug 05, 2020 12:19 pm, edited 1 time in total.
Art Neuendorffer

A vent

Re: APOD: NGC 2442: Galaxy in Volans (2020 Aug 04)

Post by A vent » Wed Aug 05, 2020 3:14 am

I was just making a point.

User avatar
Case
Commander
Posts: 602
Joined: Sat Jun 09, 2007 10:08 pm
Location: (52°N, 06°E)

Re: APOD: NGC 2442: Galaxy in Volans (2020 Aug 04)

Post by Case » Wed Aug 05, 2020 9:37 am

A nice ‘S’ for the galactic alphabet.

User avatar
neufer
Vacationer at Tralfamadore
Posts: 17521
Joined: Mon Jan 21, 2008 1:57 pm
Location: Alexandria, Virginia

Re: APOD: NGC 2442: Galaxy in Volanſ (2020 Aug 04)

Post by neufer » Wed Aug 05, 2020 12:39 pm

Case wrote:
Wed Aug 05, 2020 9:37 am

A nice ‘S’ for the galactic alphabet.
Click to play embedded YouTube video.
https://en.wikipedia.org/wiki/S#Long_s wrote:
<<The minuscule form ſ, the long s, developed in the early medieval period, within the Visigothic and Carolingian hands, with predecessors in the half-uncial and cursive scripts of Late Antiquity. It remained standard in western writing throughout the medieval period and was adopted in early printing with movable types. It existed alongside minuscule "round" or "short" s, which was at the time only used at the end of words.>>
Art Neuendorffer