APOD: Arp 188 and the Tadpole's Tail (2012 Nov 08)

[APOD Robot]

Arp 188 and the Tadpole's Tail

Explanation: In this stunning vista, based on image data from the Hubble Legacy Archive, distant galaxies form a dramatic backdrop for disrupted spiral galaxy Arp 188, the Tadpole Galaxy. The cosmic tadpole is a mere 420 million light-years distant toward the northern constellation Draco. Its eye-catching tail is about 280 thousand light-years long and features massive, bright blue star clusters. One story goes that a more compact intruder galaxy crossed in front of Arp 188 - from right to left in this view - and was slung around behind the Tadpole by their gravitational attraction. During the close encounter, tidal forces drew out the spiral 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 right. Following its terrestrial namesake, the Tadpole Galaxy will likely lose its tail as it grows older, the tail's star clusters forming smaller satellites of the large spiral galaxy.

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[Ann]

This is so fascinating! And it is a great APOD! The original Hubble image is several years old, but the processed, improved-looking image is new.

If you look at the main galaxy itself, you can see a "tail" of stars hanging down from the lower left side of the disk, pointing slightly to the right. Could the intruder galaxy have come this way, leaving a tail of stars behind? And then it was caught by the larger galaxy's gravity and was slung back and to the right. The intruder galaxy is peeking through at about two o'clock, to the right of some massive bright blue clusters in the larger galaxy. The small galaxy forms an "X" with one of the larger galaxy's bright spiral arms, but you can see the dust lane of the disk of the intruder galaxy.

Really fascinating! Thanks!

Ann

[muehlner]

This photo seems to be presented as a mirror image, according to http://hubblesite.org/newscenter/archiv ... 1/image/a/ .
If that is the case then "upper left" would really mean upper right in the shown image and make more sense as the location of the other colliding galaxy.

[bystander]

APOD Collection: Peculiar Galaxies (Arp)

[bystander]

This photo seems to be presented as a mirror image, according to http://hubblesite.org/newscenter/archiv ... 1/image/a/.
If that is the case then "upper left" would really mean upper right in the shown image and make more sense as the location of the other colliding galaxy.

Yes, thank you. The text was adapted from previous APODs and that got overlooked. The PTBs have been informed and the text fixed here.

[starsurfer]

This has been one of my alltime favourite HST images and it's great to see it in a new light. In this version, I particularly notice another galaxy with a tidal tail seen near bottom right. I think this might be a companion of Arp 188 that has also been affected by the encounter.

[Haydon]

If I was a conspiracy theorist, I'd be asking what was covered up on the lower right side of the image using the duplicate tool / copy/paste.

[neufer]

[b][color=#0000FF]Tadpole stage of Haswell's frog[/color][/b]

---

<<A tadpole is the larval stage in the life cycle of an amphibian, particularly that of a frog or toad. They are usually wholly aquatic, though some species have tadpoles that are terrestrial. The name "tadpole" is from Middle English taddepol, made up of the elements tadde, "toad", and pol, "head" (modern English "poll"). Similarly, "polliwog" is from Middle English polwygle, made up of the same pol, "head" and wiglen, "to wiggle". .

During the tadpole stage of the amphibian life cycle, most respire by means of autonomous external or internal gills. They do not usually have arms or legs until the transition to adulthood, and typically have dorsal or fin-like appendages and a tail with which they swim by lateral undulation, similar to most fish. As a tadpole matures, it most commonly metamorphosizes by gradually growing limbs (usually the legs first, followed by the arms) and then (most commonly in the case of frogs) outwardly absorbing its tail by apoptosis. Lungs develop around the time of leg development, and tadpoles late in development will often be found near the surface of the water, where they breathe air. During the final stages of external metamorphosis, the tadpole's mouth changes from a small, enclosed mouth at the front of the head to a large mouth the same width as the head. The intestines shorten to accommodate the new diet. Most tadpoles are herbivorous, subsisting on algae and plants. Some species are omnivorous, eating detritus and when available, smaller tadpoles.

Despite their soft-bodied nature and lack of mineralised hard parts, fossil tadpoles (around 10 cm in length) have been recovered from Upper Miocene strata. They are preserved by virtue of biofilms, with more robust structures (the jaw & bones) preserved as a carbon film. In Miocene fossils from Libros, Spain, the brain case is preserved in calcium carbonate, and the nerve cord in calcium phosphate. Other parts of the tadpoles' bodies exist as organic remains and bacterial biofilms, with sedimentary detritus present in the gut. Tadpole remains with telltale external gills are also known from several of the Labyrinthodont groups.>>

[jimbo48]

If I was a conspiracy theorist, I'd be asking what was covered up on the lower right side of the image using the duplicate tool / copy/paste.

I noticed this obvious copy/paste also. Anyone have a link to the original Hubble archive photo so we can see what was "pasted over" by Bill Snyder (the processor, http://billsnyderastrophotography.com/?page_id=2464 )?

Nevermind, here's a link to the archive original. Easy to see that the processor just copied a section to create a square frame for his finished print.
http://hla.stsci.edu/cgi-bin/display?im ... 20UGC10214

[emc]

Naming this galactic merger “Tadpole” is a tad polarizing.

[orin stepanek]

Beautiful photo; and a lot of background galaxies as a bonus!

[Craine]

I am also curious about the galaxy at the bottom-center. It looks like it has two jets coming out of its center.

Does anybody know this galaxy's designation by any chance?

[Boomer12k]

They must have a really interesting view of their sky over there...awesome picture, post processing can really improve a shot....take my M27 for example. Astrophotographer Tony Hallas gave me some good, simple advise.



:---[===] *

[ddorn777]

Neat picture! But it brings up a question I've had in my mind for a while. Would a star system existing in a small cluster (maybe even VERY small) separate from a "galaxy" environment (either orbiting a galaxy or separate) be more or less likely to harbour life? Would the cosmic radiation background be more or less? Would orbit stability affect the chances? What other factors would be involved?

Okay, maybe that's more than one question, but essentially, would the probability of life be higher or lower, out there in the open?

[RJN]

This photo seems to be presented as a mirror image, according to http://hubblesite.org/newscenter/archiv ... 1/image/a/.
If that is the case then "upper left" would really mean upper right in the shown image and make more sense as the location of the other colliding galaxy.

Yes, thank you. The text was adapted from previous APODs and that got overlooked. The PTBs have been informed and the text fixed here.

Thanks everyone. The text has now been made "right". - RJN

[Fafers]

I am also curious about the galaxy at the bottom-center. It looks like it has two jets coming out of its center.
Does anybody know this galaxy's designation by any chance?

I noticed it too. Jets or the telltale sign of another colision/merger?

[Craine]

I am also curious about the galaxy at the bottom-center. It looks like it has two jets coming out of its center.
Does anybody know this galaxy's designation by any chance?

I noticed it too. Jets or the telltale sign of another colision/merger?

Not sure. The galaxy seems fairly flat and undisturbed. If it is a merger then it is can't be much more then a dwarf galaxy going through the disc. And the 'jets' seem to aim directly at the center, which would be quite a coincidence for a merger.

[Ann]

I am also curious about the galaxy at the bottom-center. It looks like it has two jets coming out of its center.

Does anybody know this galaxy's designation by any chance?

Maybe possibly maybe that galaxy is PGC 57108. If it is, then its B magnitude is 15.5, very faint indeed. All that my software tells me about this galaxy is its B magnitude and its position. All right, it does say two other things, too. It says that the major axis of this galaxy is the same length as the minor axis, which suggests a face-on spiral or an elliptical, very different from the galaxy in today's APOD. All right, this estimate was probably made before there were any good pictures of the galaxy, which may well have looked like a blurry smudge to the people who originally classified it. But my software also says that the surface brightness of this galaxy is quite high, which actually suggests an edge-on spiral like the one we can see in today's APOD.

Whether or not the galaxy we see is actually PGC 57108, I would say that the "tail" emanating from the center of it is almost certainly some sort of tidal tail, produced by interaction with another (perhaps quite small) galaxy. Perhaps, indeed, the small bright "clump" sitting almost in the middle of this tail may be the culprit. If so the long stellar stream may come from the very small dwarf, not from the larger edge-on spiral.

Ann

[Mr. Toad]

I am also curious about the galaxy at the bottom-center. It looks like it has two jets coming out of its center.

Does anybody know this galaxy's designation by any chance?

Whether or not the galaxy we see is actually PGC 57108, I would say that the "tail" emanating from the center of it is almost certainly some sort of tidal tail, produced by interaction with another (perhaps quite small) galaxy. Perhaps, indeed, the small bright "clump" sitting almost in the middle of this tail may be the culprit. If so the long stellar stream may come from the very small dwarf, not from the larger edge-on spiral.

Ann

It looks to me as if the tail is a disconnected portion of the downward extending tail from the "intruder" galaxy and that it is in the foreground of the more distant flat spiral galaxy "PGC 57108".

[austinjuan]

what is the single biggest galaxy there is right now known to science and how many milky ways (not candy bars) would fit in it?

[neufer]

what is the single biggest galaxy there is right now known to science and how many milky ways (not candy bars) would fit in it?

• Elliptical galaxy IC 1011 "is 60 times larger than the Milky Way"

<<IC 1011 is a galaxy described as a compact elliptical galaxy with apparent magnitude of 14.7, and with a redshift of z=0.02564 (SIMBAD) or 0.025703 (NASA), yielding a distance of 100 to 120 Megaparsecs. Its light has taken 349.5 million years to travel to Earth. IC 1011's calculated age is approximately 12.95 billion years. The IC designation comes from the Index Catalogue.>>

[neufer]

would the probability of life be higher or lower, out there in the open?

• Yes it would.

[Anthony Barreiro]

would the probability of life be higher or lower, out there in the open?

• Yes it would.

Lol (inspiring a raised eyebrow from my coworker across the hall). This is another moment when I wish starship asterisk had a like button.

It's really hard to calculate probabilities when your sample of planets known to harbor life is n=1.

By the way, this is a beautiful photo, and a masterfully clear caption. I've seen pictures of this galaxy before, but I never understood the path of the wandering galaxy, and never imagined it could be seen lurking behind Arp 188 in the opposite direction from the tidal tail. That's pretty sneaky!

[Chris Peterson]

It's really hard to calculate probabilities when your sample of planets known to harbor life is n=1.

So true. That said, however, we can actually calculate the stability of planetary systems given different interstellar environments, and stars that are in more thinly populated regions almost certainly have much longer lived planetary systems... which we might reasonably suggest increases the odds of them supporting advanced life. What it increases those odds from, of course, is anybody's guess.

[Wadsworth]

Am I the only one that is still unclear as to where the 'intruder' galaxy is?