APOD: Barred Spiral Galaxy NGC 1073 (2012 Feb 20)

[Wolf kotenberg]

I would guess, perhaps even advance, the idea thia thing started out, a really long time ago in a galaxy really far away, as a gamma ray burst creator that over galactic times evolved into a barred galaxy, or not !

[ricardelico]

The galaxy's core bar in this picture resembles itself a galaxy. Could it be that core bars are residuals of disrupted rotation planes?

[luigi]

This was a fantastic APOD and It brought to my mind the Large Magellan Cloud inmediately. I know the LMC is classified as an irregular galaxy but seeing this photo and the LMC I really think it's a barred galaxy (sans-spiral) but as I'm not familiar with galaxy classification parameters it probably isn't.

[Guest]

I apologize for having interrupted your scholarly forum earlier today.

I AM PROUD that during my lifetime, Man walked on the Moon.

Today belonged to John Glenn. Barred Spiral Galaxy NGC 1073 could have waited until tomorrow.

Charles

[Ann]

This was a fantastic APOD and It brought to my mind the Large Magellan Cloud inmediately. I know the LMC is classified as an irregular galaxy but seeing this photo and the LMC I really think it's a barred galaxy (sans-spiral) but as I'm not familiar with galaxy classification parameters it probably isn't.

There are definite similarities between NGC 1073 and the Large Magellanic Cloud, but there are also important differences.

Credit: Adam Block

The bar of NGC 1073 contains a bright central condensation, a nucleus. The ring around the bar of NGC 1073 is well established. NGC 1073 has moderately well-established arms.

NGC 1073 may not have an emission nebula as large as the Tarantula Nebula.

Credit: Eckhard Slawik

The bar of the LMC lacks a central brightening. There is no nucleus. There is an incipient ring structure, but it is not well established. There are no real arms.








Ann

[Chris Evans]

Light takes about 55 million years to reach us from NGC 1073. How do you know for absolute that light travels that way??? Why don't you say that current knowledge seems to say it takes 55 million years to get here?

Must you insist on proving that all those million years and billion years are true...

Admit it, you really don't know what your talking about!

[Christopher Evans]

i quote you now, "Light takes about 55 million years to reach us from NGC 1073"

Why do you not say that your guessing about light travel? Or say current knowledge seems to say your quote?

Just admit that you do not know.

i do not believe all those millions and billions stuff. Get to work and figure out what is really going on in Space please.

Thanks

[Christopher Evans]

Who lost the drive to understand Space? The 1960's are over now. What can you do today to get going. People are different( it's a new generation). Space is just as important as it ever was. We used it wrongly so far. Too many TV satellites. TV can be broadcast digitally on local towers with only a few satellites for free (except commercials).

Let's stop watching TV and start working on all the new data comming from Voyager I & II, and Hubble, etc...

Admit that current knowledge thinkis only partially true. Christopher Kraft believes and said in his Biography that the speed of light is not a limiting factor. He said that he believed that objects can travel faster than the speed of light. So stop all this billions and millions stuff and evolve stuff and figure out what is really going on please.


Thanks,

Please do not censure this post. Post immediatly.

[Christopher Evans]

i am sorry to say that the speed of light is not the speed limit. Why not figure out what is really happening?

Thanks,

Chris

[DavidLeodis]

Another great image from the Hubble Space Telescope. It still is a marvelous space observatory.

I have a couple of points though about the explanation to this APOD. The " Fortuitously the above image not only caught the X-ray bright star system IXO 5, visible on the upper left" (my underlining) seems to imply to me that IXO 5 would be at least visually obvious but I could not defintely make it out even in the enlarged version of the image. The explanation also refers to "red emission nebulas" but it is not obvious where they are even in the enlarged version. I wonder if anyone else has a problem seeing IXO 5 and the red emission nebulas in the image? The enlarged version does show some nice other galaxies.

[geckzilla]

i do not believe all those millions and billions stuff. Get to work and figure out what is really going on in Space please.

Why don't you "believe" in the millions and billions "stuff"? There is a lot of scientific evidence to backup the idea that objects are millions and even billions of light years away from us. If you feel compelled to believe otherwise, then why don't you present the evidence for your belief? Or did you have any?

[owlice]

I think this question kind of sums everything up (emphasis mine)....

Must you insist on proving that all those million years and billion years are true...

The answer, of course, is yes.

[Chris Peterson]

Space is just as important as it ever was. We used it wrongly so far. Too many TV satellites. TV can be broadcast digitally on local towers with only a few satellites for free (except commercials).

Hardly any TV is broadcast from satellites. The satellites distribute the signals to regional centers, where they are then carried by ground-based systems.

Christopher Kraft believes and said in his Biography that the speed of light is not a limiting factor. He said that he believed that objects can travel faster than the speed of light.

If Kraft said that, he's wrong. In any case, he really isn't qualified to make such an assertion in the first place.

[neufer]

[url=http://www.chris-craft.org/index.php][b][size=150]Chris-Craft[/size][/b][/url][b][color=#0000FF][size=150] traveling faster than light[/color][/b][/size] :!:

---

Christopher Kraft believes and said in his Biography that the speed of light is not a limiting factor. He said that he believed that objects can travel faster than the speed of light.

If Kraft said that, he's wrong. In any case, he really isn't qualified to make such an assertion in the first place.

[Ann]

Another great image from the Hubble Space Telescope. It still is a marvelous space observatory.

I have a couple of points though about the explanation to this APOD. The " Fortuitously the above image not only caught the X-ray bright star system IXO 5, visible on the upper left" (my underlining) seems to imply to me that IXO 5 would be at least visually obvious but I could not defintely make it out even in the enlarged version of the image. The explanation also refers to "red emission nebulas" but it is not obvious where they are even in the enlarged version. I wonder if anyone else has a problem seeing IXO 5 and the red emission nebulas in the image? The enlarged version does show some nice other galaxies.

It is likely that IXO-5 is not particularly bright in optical light. The compact source may be a black hole of about ten solar masses or less. It could also be a neutron star, whose mass might be as low as about 1.4 solar masses. A black hole will not emit any optical light at all, and a neutron star will emit extremely little optical light.

The accretion disk will obviously emit some optical light, but the accretion disk will be small, which in itself will make it relatively faint.

Most of the optical light from the system, therefore, will come from the "normal star component" of the X-ray binary. This normal star could be big, bright and massive, but it could also be relatively small. Consider Algol. It consists of a blue main sequence star of spectral class B8 and a K-type "emaciated giant". The blue star has stolen so much mass from the yellow component that the blue star now dominates the light of this binary, and the K-type giant probably shines no brighter than 10-15 Suns.

If the optical component of IXO-5 is in any way similar to the K-type component of Algol, then the optical light that is emitted by IXO-5 will be rather faint. Still, Hubble was able to see two possible candidate stars. The reason why scientists can't say which of the stars inside the circle is IXO-5 is because the Chandra X-ray Telescope, which discovered IXO-5, can't pinpoint the location of the X-ray source with enough precision for Hubble to irrefutably match the X-ray source with just one optical source.

David Leodis, you also wondered why the red emission nebulae don't look red in this image. That is because of the filters used for this image. The filters used were one blue filter, centered at 435 nm, and one orange filter, centered at 606 nm. However, according to Chris Peterson, the orange filter is really a "clear filter" that detects most optical light from green to red.

But what about the red emission nebulae? They glow red because they emit Ha light at 656 nm. However, they also emit aqua-blue light at 486 nm.

The 606 nm filter used for this image detected the 656 nm Ha light. The blue filter detected the 486 nm Hβ light. A pseudo-green filter was created by adding the light passed by the 606 nm filter to the light passed by the 435 nm filter.

The result was that the blue filter detected the aqua-blue light at 486 nm, which was mapped as blue. The clear filter detected the red light at 656 nm, which was shown as red. The pseudo-green filter detected both the red Ha and the aqua-blue Hβ light, whose combined light was mapped as green.

This means that the red emission nebulae were clearly detected by all the filters used for this image, and the nebulae therefore look mostly white.

Ann

[DavidLeodis]

Thank you Ann for that explanation as to why the red nebulae were not red in the image that the explanation to the APOD seems to imply they would be. Your help is appreciated.

[Beyond]

Thank you Ann for that explanation as to why the red nebulae were not red in the image that the explanation to the APOD seems to imply they would be. Your help is appreciated.

Very nice post, David. Do you realize that according to the rules, after you post your next post, you will be declared offically insane
But it does give you the benefit of choosing a rank for yourself, if it's not too outrageous. Hint, captain is already taken.(twice)

[Chris Peterson]

I have a couple of points though about the explanation to this APOD. The " Fortuitously the above image not only caught the X-ray bright star system IXO 5, visible on the upper left" (my underlining) seems to imply to me that IXO 5 would be at least visually obvious but I could not defintely make it out even in the enlarged version of the image. The explanation also refers to "red emission nebulas" but it is not obvious where they are even in the enlarged version. I wonder if anyone else has a problem seeing IXO 5 and the red emission nebulas in the image? The enlarged version does show some nice other galaxies.

I'm going to offer a somewhat different explanation than that given by Ann.

Here is the spectrum captured by the two filters used. As noted, the green channel was then synthesized by adding the other two. Ionized hydrogen regions typically only emit one strong line, the 656 nm hydrogen alpha wavelength (shown on the graph). In the final image, that "color" will be a mix of red and green only, as the F435W filter has no transmittance there. Equal amounts of red and green produce yellow, but the amounts are unlikely to be quite the same because it is customary to weight each color channel differently, to account for differences in sensor response, exposure time, and even aesthetics. Slightly scaling down the green component pushes the yellow towards orange. In addition, there is some continuum light from the stars embedded in the nebulas, which is basically white, and which acts to desaturate the orange of Ha. And in fact, if you look in the galaxy arms, you can see nebulous regions by their structure, and those regions are moderately desaturated orange.

While ionized hydrogen regions also emit the 486 nm hydrogen beta line, it is much weaker than the hydrogen alpha line. The resultant cyan color (blue + green) in the final image may be strong enough to further desaturate the orange Ha somewhat, but I doubt it shifts the color much.

[DavidLeodis]

Thank you Ann for that explanation as to why the red nebulae were not red in the image that the explanation to the APOD seems to imply they would be. Your help is appreciated.

Very nice post, David. Do you realize that according to the rules, after you post your next post, you will be declared offically insane
But it does give you the benefit of choosing a rank for yourself, if it's not too outrageous. Hint, captain is already taken.(twice)

This post will therefore make me officially insane but I doubt anyone will spot anything new! 'Insane in the mainframe' is a particularly fond episode of mine in Futurama.

Edit added moments after posting. Thanks Chris for your help which came in when I was typing my original message.

[gilgamorph]

An inspiring APOD!

Any help on the nomencalture involved?

An hour of browsing found lots of catalogue abbreviations (HD,BD,GC,SHO,HR,PPM,NGC,etc) but I was unable to locate a link that would decifer the references. Obviously QSO designates a Quasi Stellar Object and PKS is probably a catalog of radio sources (although I couldn't confirm this or expand the acronym). VV96 is probably a designation for a variable star, but in what catalog? The J024333.6 reference eludes me, but since the numbers associated with the objects are so similiar I'm assuming they are coordinates. (RA+dec ?)

Thanks for all your elucidating efforts !!!

(addendum) IXO =? intense x-ray object why the differing format for dec?

[Chris Peterson]

An hour of browsing found lots of catalogue abbreviations (HD,BD,GC,SHO,HR,PPM,NGC,etc) but I was unable to locate a link that would decifer the references. Obviously QSO designates a Quasi Stellar Object and PKS is probably a catalog of radio sources (although I couldn't confirm this or expand the acronym).

PKS refers to the Parkes Radio Sources catalog.

VV96 is probably a designation for a variable star, but in what catalog?

VV refers to the Vorontsov-Velyaminov Interacting galaxies catalog and to the Vatican Observatory Variable star catalog.

The J024333.6 reference eludes me, but since the numbers associated with the objects are so similiar I'm assuming they are coordinates. (RA+dec ?)

Correct. JRA+dec is a standard notation used by many catalogs.

Bottom line, there are hundreds of catalogs, many of which use ambiguous identifiers, or for which more than one identifier is used, and many objects are in a dozen or more catalogs. It can be pretty confusing.

[Christopher Evans]

I am not so sure that billions of years ago the universre formed. Isn't there a simpler explanation available?

[Christopher Evans]

i do not believe all those millions and billions stuff. Get to work and figure out what is really going on in Space please.

Why don't you "believe" in the millions and billions "stuff"? There is a lot of scientific evidence to backup the idea that objects are millions and even billions of light years away from us. If you feel compelled to believe otherwise, then why don't you present the evidence for your belief? Or did you have any?

Space is curved. Perhaps light can travel in different ways that we don't understand. Your entrenched in your belief and i in mine and so the challenge is to try to see who is right. i have no knowledge to prove that i am right but only a gut feeling. You scientist used to say that nobody could go faster than the speed of sound but that was proved wrong. So will your assertions about light speed be proved wrong also.

[owlice]

I am not so sure that billions of years ago the universre formed. Isn't there a simpler explanation available?

Sure, but there's no science to back up "simpler" explanations. You don't like where the science leads. Okay, but this is a science forum; please don't expect it to be something else just because you want a "simpler" explanation.

[Ann]

Chris Evans wrote:
i have no knowledge to prove that i am right but only a gut feeling. You scientist used to say that nobody could go faster than the speed of sound but that was proved wrong. So will your assertions about light speed be proved wrong also.

I am most certainly not a moderator of this forum, but I believe, nevertheless, that you are allowed to express a lot of opinions about the Astronomy Pictures of the Day that are posted here. As for whether or not anything can go faster than light, the question is far from settled. In any case, if anything can go faster than light, it almost certainly only refers to ultra-light particles like neutrinos.

Fine. But you apparently want an argument, Chris. As owlice said, this is a science forum. If you don't have any sort of scientific argument, but only a gut feeling, then you don't have a case at a science forum like this one.

Ann