APOD: Barred Spiral Galaxy NGC 1300 (2016 Jan 09)

[APOD Robot]

Barred Spiral Galaxy NGC 1300

Explanation: Big, beautiful, barred spiral galaxy NGC 1300 lies some 70 million light-years away on the banks of the constellation Eridanus. This Hubble Space Telescope composite view of the gorgeous island universe is one of the [url=http://hubblesite.org/newscenter/archive/releases/2005/01/image/a/warn/" >largest Hubble images ever made of a complete galaxy. <a href="http://heritage.stsci.edu/2005/01/fast_facts.html]NGC 1300[/url] spans over 100,000 light-years and the Hubble image reveals striking details of the galaxy's dominant central bar and majestic spiral arms. In fact, on close inspection the nucleus of this classic barred spiral itself shows a remarkable region of spiral structure about 3,000 light-years across. Like other spiral galaxies, including our own Milky Way, NGC 1300 is thought to have a supermassive central black hole.

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[Ann]

Happy eleventh birthday, Hubble Heritage Team, ESA, NASA picture of NGC 1300! The "composite view" link shows that this image was originally released on January 10, 2005. Okay, the birthday cake will have to wait for tomorrow.

Click to view full size image

Today's APOD is certainly a fantastic portrait of an iconic galaxy. Few galaxies are so shamelessly barred as this one. The first time I saw a picture of NGC 1300, I asked myself how a galaxy could possibly get so weirdly shaped. At least part of the answer to that question can be found if you look at the "bar ends", where the long bar suddenly turns into spiral arms. It is precisely at the bar ends that the NGC 1300 has most of its star formation. That is where you find most of the galaxy's pink nebulas and young blue stars. That is where the incubator of NGC 1300 hatches the majority of its new stars. That is where NGC 1300 is growing in size - at the ends of its bar. And that means, in fact, that the bar of NGC 1300 is getting longer to this day. It just keeps getting longer. As long as a barred galaxy has most of its star formation at the ends of its bar, the bar will keep getting longer.

Click to view full size image

NGC 1300. Credit: Nicole Bies and Esidro Hernandez/Adam Block/NOAO/AURA/NSF

Today's APOD is such an iconic portrait of NGC 1300 that when I first googled "NGC 1300 galaxy" and asked for pictures, I found no other pictures than the Hubble/ESA/NASA one! But I would like to show you another one, an old NOAO picture. In the NOAO picture you can see the outer arms of NGC 1300, which are invisible in the Hubble image.

But you can also see how faint the long bar of NGC 1300 really is. And you can see how brilliantly bright the nuclear region of NGC 1300 really is compared to the rest of the galaxy. Of course, this is quite typical of galaxies. They usually have bright or even brilliant nuclear regions, but most modern photography tries to "even out" the brightness profiles of the galaxies, in order to bring out more detail.

Click to view full size image

NGC 1365. Credit and copyright:
SSRO-South (R.Gilbert,D.Goldman,J.Harvey,D.Verschatse) - PROMPT (D.Reichart)

Finally I can't resist showing you another kind of very barred galaxy, NGC 1365. But while NGC 1300 and NGC 1365 are similarly barred, NGC 1300 has pulled its inner spiral arms in close to its bar, the spiral arms of NGC 1365 are flying high over its barred middle. My impression, which might be totally wrong, is that the bar (and central black hole?) of NGC 1300 is more massive than the bar (and black hole) of NGC 1365. NGC 1300 is "straitjacketing" its inner spiral arms, while NGC 1365 sends its spiral arms flying.

Ann

[Boomer12k]

Great image...."The Eye of the Storm"...so to speak...

:---[===] *

[ta152h0]

there must be some weird interactions in the Universe, completely unknown still. Maybe something similar to the Focke-Wulf Flitzer power train

[bmesser]

A really great image, but you've used the exact same image before and it's a big universe. Any chance of seeing NGC 1299 or 1301? Perhaps they aren't quite as impressive as NGC 1300 but at least they would be new.

[geckzilla]

A really great image, but you've used the exact same image before and it's a big universe. Any chance of seeing NGC 1299 or 1301? Perhaps they aren't quite as impressive as NGC 1300 but at least they would be new.

Welcome to the weekend. You'll notice there is nearly always a rerun to give the editors a little break and replay some great APODs for people who haven't seen them before. It's no accident that this has occurred.

[Guest]

Mind blowing view and well worth re-showing. I love the presence of a myriad of galaxies in the background, making sure we feel our insignificance.
Sadly, that doesn't seem to work with politicians, dictators, religious bigots etc.

[tomatoherd]

I counted at least 23 galaxies seen THROUGH this featured galaxy. And probably an order of magnitude greater if one could see every one out to the limit, or would there be more?
Guest: a feeling of insignificance alone does not inspire good stewardship of this spaceship planet or anything else. It also takes awe, respect, even love, and probably accountability to something greater than the law of man (a mutable, sometimes capricious law). And BTW, it doesn't work with non-religious bigots either.

[rstevenson]

Trying to see the full image, I got...

The image “http://imgsrc.hubblesite.org/hu/db/imag ... ll_jpg.jpg” cannot be displayed because it contains errors.

Rob

[bystander]

Trying to see the full image, I got...

The image “http://imgsrc.hubblesite.org/hu/db/imag ... ll_jpg.jpg” cannot be displayed because it contains errors.

Rob

I was getting that last night, but I just tried it and was able to load it with no problems. Maybe your browser is running out of available memory. Try downloading the image and opening it with another image viewer.

[Steve Dutch]

What's especially neat is that you can look THROUGH NGC 1300 to distant galaxies beyond it.

[neufer]

[b]M 83 (the Southern Pinwheel Galaxy) composite of the [color=#FF0000]radio light (neutral hydrogen in red)[/color] with [color=#0000FF]ultraviolet light (hot newly-formed stars)[/color]. Image credit: NASA / JPL-Caltech / VLA / MPIA.[/b]

---

<<Up to two-thirds of all spiral galaxies contain a bar. The current hypothesis is that the bar structure acts as a type of stellar nursery, fueling star birth at their centers. The bar is thought to act as a mechanism that channels gas inwards from the spiral arms through orbital resonance, in effect funneling the flow to create new stars. This process is also thought to explain why many barred spiral galaxies have active galactic nuclei, such as that seen in the Southern Pinwheel Galaxy.

The creation of the bar is generally thought to be the result of a density wave radiating from the center of the galaxy whose effects reshape the orbits of the inner stars. This effect builds over time to stars orbiting further out, which creates a self-perpetuating bar structure.

Bars are thought to be temporary phenomena in the lives of spiral galaxies; the bar structures decay over time, transforming galaxies from barred spirals to more "regular" spiral patterns. Past a certain size the accumulated mass of the bar compromises the stability of the overall bar structure. Barred spiral galaxies with high mass accumulated in their center tend to have short, stubby bars. Since so many spiral galaxies have bar structures, it is likely that they are recurring phenomena in spiral galaxy development. The oscillating evolutionary cycle from spiral galaxy to barred spiral galaxy is thought to take on the average about two billion years.

Recent studies have confirmed the idea that bars are a sign of galaxies reaching full maturity as the "formative years" end. A team led by Kartik Sheth of the Spitzer Science Center at the California Institute of Technology in Pasadena discovered that only 20 percent of the spiral galaxies in the distant past possessed bars, compared with nearly 70 percent of their modern counterparts.>>

<<The Chalmun's Cantina (often called the Mos Eisley Cantina) is a fictional bar of the Star Wars universe located in the "pirate city" of Mos Eisley on the planet Tatooine. It is the haunt of freight pilots and other dangerous characters of various alien races and contains booths, a bar counter, and some free-standing tables, and sometimes a band of musicians named Figrin D'an and the Modal Nodes. The establishment is extremely rough in nature, and the clientele and the management give incidents of deadly violence no more than a moment's attention. Droids are not allowed inside; a droid detector near the front door alerts the management of any entering droid.>>

<<Maz Kanata: A wise and perceptive figure operating a somewhat shady cantina on the peaceful forest planet, Takodana. J.J. Abrams said Kanata has "lived over a thousand years. She's had this watering hole … and it's like another bar that you'd find in a corner of the Star Wars universe." According to Abrams, the character was based on his former high school English teacher, Rose Gilbert, who lectured at the Palisades Charter High School from 1961 to 2013. "I mentioned Rose in an early story meeting as a sort of timeless, wise figure that I'd actually known in my life.">>

[Ann]

Wikipedia wrote:
Past a certain size the accumulated mass of the bar compromises the stability of the overall bar structure. Barred spiral galaxies with high mass accumulated in their center tend to have short, stubby bars.

I guess the bar of NGC 1300 isn't that massive, then, since it hasn't collapsed under its own weight. It does have a very low surface brightness.

And what about the central black hole of NGC 1300?

According to Supermassive black hole mass measurements for NGC 1300 and NGC2748 based on HST emission-line gas kinematics the central black hole of NGC 1300 most likely has a mass of around 66 million solar masses. That's a lot, more than ten times the mass of the central black hole of the Milky Way, but it is very, very far from being any sort of record holder. In fact the central black hole of Andromeda might be heavier.

Ann

[neufer]

And what about the central black hole of NGC 1300?

Color Commentators aren't authorized to discuss black holes...out of their jurisdiction.

[Chris Peterson]

And what about the central black hole of NGC 1300?

Color Commentators aren't authorized to discuss black holes...out of their jurisdiction.

Black is the new blue.

[Beyond]

Yes, if you get to close to a black hole, you could end up very black and blue!

[Nitpicker]

I suppose Ann is still able to be thrilled by all the blue light that is captured by black holes. It is a conceptual thing.

[ta152h0]

How can you tell the difference between blue light due to red shift or actual blue emissions ?

[geckzilla]

How can you tell the difference between blue light due to red shift or actual blue emissions ?

By knowing how far away what you're looking at is.

[Chris Peterson]

How can you tell the difference between blue light due to red shift or actual blue emissions ?

By visual inspection, you can't for sure. You may know something about what the object should look like, and therefore recognize of there is a large redshift, but you can't count on that. From the standpoint of scientific analysis, you can tell the difference because you aren't looking at "color", but at the spectral structure of the light. In most cases, that means identifying specific spectral lines (like those of hydrogen) that are measured at a different wavelength than we know they are actually at. From that the precise red (or blue) shift can be determined. In other cases, the spectrum shows a particular shape (such as a blackbody curve) that will be uniquely shifted- in such cases it is possible to measure the shift by looking at the intensity ratios of two or more parts of the spectrum.

Visually, redshifted objects are not necessarily redder, and blueshifted objects are not necessarily bluer than they would otherwise appear (although in many cases they are, especially for fairly small shifts).

[Ann]

I suppose Ann is still able to be thrilled by all the blue light that is captured by black holes. It is a conceptual thing.

Actually, no. When it comes to astronomy, I get my biggest kicks out of seeing blue objects that I know (or believe) are blue for real. If I know that an image is a false-color (or mapped color) one, seeing blue objects in it doesn't make me happy, because then I know that the blue objects aren't blue for real.

I remember reading about cool white dwarfs that get bluer again as they keep cooling. I was horribly disappointed when I found that these white dwarfs, instead of actually getting bluer as they get cooler, are becoming less infrared than they "should" be when they have reached a certain temperature. The energy that ought to have been emitted by the white dwarf as certain wavelengths of infrared light instead gets shifted into the red part of the visual spectrum. So these stars become considerably brighter in red light yet fainter in infrared light as they get cooler. And because red is a "bluer" color than infrared - that is, it is a more short-wave color than infrared - these stars actually get "blue" again when they get red again! I was horribly disappointed!

But of course, if a mapped color image like in the High Energy Andromeda APOD shows a lot of yellow sources and one blue one, then I'd like to know why that "blue" object is differently colored than the rest of them, and what real, physical properties it has that sets it apart from the others.

Ann

[quigley]

Thank you Ann and Neufer for the great explanations of the origins of galactic bars. Upon viewing this image, the first question that came to mind was, "What causes such distinctive formations to occur?" You answered that. So the spiral arms "peel" off stars from the ends of the bars over time?

[Ann]

Thank you Ann and Neufer for the great explanations of the origins of galactic bars. Upon viewing this image, the first question that came to mind was, "What causes such distinctive formations to occur?" You answered that. So the spiral arms "peel" off stars from the ends of the bars over time?

Again, I'm not the best person to elaborate, but...

Source:http: //www.astro-tom.com/technical_data/elliptical_orbits.htm

I think that basically two things are happening. First and most importantly, the orbits of the stars near the center of the galaxy start following elliptical (elongated) orbits around the center of the galaxy. They then synchronize their orbits so that all or most stars in that part of the galaxy follow more or less the same elliptical orbit. Think of it like this. An elliptical orbit could be "lying down" or "standing up". To get a bar, all or most of the stars in the bar must orbit in the same direction, "lying down" or "standing up". The stars do indeed synchronize their orbits.

Click to view full size image

NGC 1097. ESA/Hubble & NASA

Another very important thing about barred galaxies is that they have dust lanes running from a little ring in their centers out along the bar all the way to the first spiral arm. On one side, the dust lane is running "above" the bar (not really, but sort of) and on the other side, it is running "below" the bar. Personally I don't understand math, but I will hazard a guess that the dust lanes along the bar are "shepherding" the stars in the bar along their elliptical orbits.

I believe that the dust lanes also move starmaking material like gas and dust into two places in a barred galaxy: it is sent into the ring around the nucleus, where we often find a lot of star formation in barred galaxies. And it is sent to the ends of the bar. Here we often find star formation, too. I believe that star formation at the ends of a bar will make that bar grow in size.

Click to view full size image

NGC 936. Photo: SDSS.

So what happens when a barred galaxy stops making new stars? That happens when the galaxy has used up its available gas and dust, or when the gas and dust becomes too turbulent to settle down into star making. Well, for one thing, the dust lanes probably disappear from the bar, because the dust lanes are the mechanisms for funneling star making material into the ring around the nucleus and to the ends of the bar.

NGC 936 is a barred galaxy that gave up star formation long ago. It is a very "red and dead" galaxy. But you can still see a "ring" around its nucleus, and you can see that there used to be quite a lot of star formation at the ends of the bar. The bar ends are bright.

And that's what I can say about the formation of bars, I think.

Ann

[Chris Peterson]

I think that basically two things are happening. First and most importantly, the orbits of the stars near the center of the galaxy start following elliptical (elongated) orbits around the center of the galaxy. They then synchronize their orbits so that all or most stars in that part of the galaxy follow more or less the same elliptical orbit.

A couple of points. First, a slightly pedantic one- all closed orbits are elliptical (including perfectly circular ones). What you're discussing is eccentricity. Second, I'm doubtful that the stars, particularly in the center of a galaxy, have very eccentric orbits. There are dynamical mechanisms that work to circularize orbits in dense regions. Perturbations may briefly increase eccentricity, but the orbits will probably circularlize rather quickly, with a new orbital radius (or semimajor axis). The density structure that we call a bar suggests orbital resonances, but not what I'd call a synchronization of eccentricities in any way.

[Ann]

I think that basically two things are happening. First and most importantly, the orbits of the stars near the center of the galaxy start following elliptical (elongated) orbits around the center of the galaxy. They then synchronize their orbits so that all or most stars in that part of the galaxy follow more or less the same elliptical orbit.

A couple of points. First, a slightly pedantic one- all closed orbits are elliptical (including perfectly circular ones). What you're discussing is eccentricity. Second, I'm doubtful that the stars, particularly in the center of a galaxy, have very eccentric orbits. There are dynamical mechanisms that work to circularize orbits in dense regions. Perturbations may briefly increase eccentricity, but the orbits will probably circularlize rather quickly, with a new orbital radius (or semimajor axis). The density structure that we call a bar suggests orbital resonances, but not what I'd call a synchronization of eccentricities in any way.

Wikipedia wrote:
In 1991 Tod R. Lauer used WFPC, then on board the Hubble Space Telescope, to image M31's inner nucleus. The nucleus consists of two concentrations separated by 1.5 parsecs (4.9 ly). The brighter concentration, designated as P1, is offset from the center of the galaxy. The dimmer concentration, P2, falls at the true center of the galaxy and contains a black hole measured at 3–5 × 107 M☉ in 1993,[73] and at 1.1–2.3 × 108 M☉ in 2005.[74] The velocity dispersion of material around it is measured to be ≈ 160 km/s.[75]

Scott Tremaine has proposed that the observed double nucleus could be explained if P1 is the projection of a disk of stars in an eccentric orbit around the central black hole.[76] The eccentricity is such that stars linger at the orbital apocenter, creating a concentration of stars.

Ann