APOD: NGC 2683: Edge On Spiral Galaxy (2014 Feb 05)

[APOD Robot]

NGC 2683: Edge On Spiral Galaxy

Explanation: Does spiral galaxy NGC 2683 have a bar across its center? Being so nearly like our own barred Milky Way Galaxy, one might guess it has. Being so nearly edge-on, however, it is hard to tell. Either way, this gorgeous island universe, cataloged as NGC 2683, lies a mere 20 million light-years distant in the northern constellation of the Cat (Lynx). NGC 2683 is seen nearly edge-on in this cosmic vista combining data and images from the ground-based Subaru telescope and the space-based Hubble Space Telescope. More distant galaxies are seen scattered in the background. Blended light from a large population of old yellowish stars forms the remarkably bright galactic core. Starlight silhouettes the dust lanes along winding spiral arms, dotted with the telltale blue glow of young star clusters in this galaxy's star forming regions.

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[Ann]

I'm always glad to see a picture of Robert Gendler here. As always, he has done the data given to him splendid justice.

NGC 2683 has been called the UFO galaxy, and it really has a shape reminiscent of a classic flying saucer.

For me, with my specific hangups, NGC 2683 looks a bit bland. This galaxy is somewhat bland and poor in star formation. Or, to put it somewhat differently, this flying saucer lacks its red nebulae brake lights.

Ann

[Boomer12k]

I do not observe well defined spiral arms with any defining space between....if there IS a Bar in the hub...it seems it would be very small...

I used to use this image for my Tablets Home Screen wallpaper....SWEET...

:---[===] *

[Sinan İpek]

What is the aproximate exposition time for an image like this? For Hubble? For Subaru? And for both of them combined?

[Cousin Ricky]

The other day on another forum, someone asked if there were any atheists who lent credence to astrology. Of course, the answer is “yes” (however few). If you look at my avatar, you’ll know what my astrological (tropical?) sign is. However, you’ll also know what I think of astrology.

Someone mentioned Chinese astrology, and I responded that if I had a Chinese background, I might use an image of Lepus, although it wouldn’t have the built-in clever pun. But I found myself wondering what constellation I would use if my background were Vietnamese.

Today’s APOD possibly answers that question.

[neufer]

NGC 2683: Edge On Spiral Galaxy

Does spiral galaxy NGC 2683 have a bar across its center?
Being so nearly like our own barred Milky Way Galaxy, one might guess it has.

• . http://www.criticalcommons.org/Members/ ... e-iv-a-new

NGC 2683 has been called the UFO galaxy, and it really has a shape reminiscent of a classic flying saucer.

[Tumbleweed]

A very slow clockwise tumble to this galaxy.

[Beyond]

The other day on another forum, someone asked if there were any atheists who lent credence to astrology. Of course, the answer is “yes” (however few). If you look at my avatar, you’ll know what my astrological (tropical?) sign is. However, you’ll also know what I think of astrology.

Someone mentioned Chinese astrology, and I responded that if I had a Chinese background, I might use an image of Lepus, although it wouldn’t have the built-in clever pun. But I found myself wondering what constellation I would use if my background were Vietnamese.

Today’s APOD possibly answers that question.

When i first saw your avatar, i didn't know what it was. After what you've just said, i still don't. At least I'm consistent.

[Tumbleweed]

A very slow clockwise tumble to this galaxy.

P.S. Comparing the mass of the galaxy, the rate of tumble, and the deflection of the leading and trailing edges will give the density of the medium the galaxy is tumbling in. Mathematicians, do your stuff.

[rstevenson]

A very slow clockwise tumble to this galaxy.

P.S. Comparing the mass of the galaxy, the rate of tumble, and the deflection of the leading and trailing edges will give the density of the medium the galaxy is tumbling in. Mathematicians, do your stuff.

Er, um, ... Tumbling? Medium?

Rob

[MarkBour]

. . . This galaxy is somewhat bland and poor in star formation. Or, to put it somewhat differently, this flying saucer lacks its red nebulae brake lights.

Ann --
Just wondering. Do edge-on galaxies show us less nebulae in general, or can we see them fine in most edge-on galaxies? I'm wondering if this galaxy is perhaps more rich in them than we can see, just that the dust lanes block our view.

[geckzilla]

. . . This galaxy is somewhat bland and poor in star formation. Or, to put it somewhat differently, this flying saucer lacks its red nebulae brake lights.

Ann --
Just wondering. Do edge-on galaxies show us less nebulae in general, or can we see them fine in most edge-on galaxies? I'm wondering if this galaxy is perhaps more rich in them than we can see, just that the dust lanes block our view.

Puffs of hydrogen alpha typically extend beyond dust lanes, ballooning out over time. I'm not sure they're not there. I think this image may simply lack narrowband data.

[Cousin Ricky]

The other day on another forum, someone asked if there were any atheists who lent credence to astrology. Of course, the answer is “yes” (however few). If you look at my avatar, you’ll know what my astrological (tropical?) sign is. However, you’ll also know what I think of astrology.

Someone mentioned Chinese astrology, and I responded that if I had a Chinese background, I might use an image of Lepus, although it wouldn’t have the built-in clever pun. But I found myself wondering what constellation I would use if my background were Vietnamese.

Today’s APOD possibly answers that question.

When i first saw your avatar, i didn't know what it was. After what you've just said, i still don't. At least I'm consistent.

The Hyades and the Pleiades didn't give it away? (OK, maybe the bits of Auriga and Orion in the field might be confusing.)

[rgendler]

. . . This galaxy is somewhat bland and poor in star formation. Or, to put it somewhat differently, this flying saucer lacks its red nebulae brake lights.

Ann --
Just wondering. Do edge-on galaxies show us less nebulae in general, or can we see them fine in most edge-on galaxies? I'm wondering if this galaxy is perhaps more rich in them than we can see, just that the dust lanes block our view.

Puffs of hydrogen alpha typically extend beyond dust lanes, ballooning out over time. I'm not sure they're not there. I think this image may simply lack narrowband data.

Yep, neither Subaru or Hubble had any narrowband h-alpha. After studying many other images on the web I decided that the HII clouds were so few and bland it wasn't worth the trouble.

[FloridaMike]

NGC 2683: Edge On Spiral Galaxy

Explanation: Does spiral galaxy NGC 2683 have a bar across its center? Being so nearly like our own barred Milky Way Galaxy, one might guess it has. Being so nearly edge-on, however, it is hard to tell.....

If we can detect a bar in our own galay which is almost perfectly edge-on why is it hard to tell if near edge-on NGC 2683 has a bar?

conversely...

If we cannot tell if near edge-on NGC 2683 has a bar how do we detect a bar in our own galaxy which is almost perfectly edge-on ?

[neufer]

If we can detect a bar in our own galay which is almost perfectly edge-on why is it hard to tell if near edge-on NGC 2683 has a bar?

conversely...

If we cannot tell if near edge-on NGC 2683 has a bar how do we detect a bar in our own galaxy which is almost perfectly edge-on ?

Astronomers can determine the distances of certain bright stars to within ~10%.

This is just sufficient to detect a bar like structure in the Milky Way
though not so for the more distant NGC 2683

http://asterisk.apod.com/viewtopic.php? ... 82#p216382

<<The nature of the Milky Way's bar which extends across the Galactic Center is actively debated, with estimates for its half-length and orientation spanning between 1–5 kpc (short or a long bar) and 10–50°. Certain authors advocate that the Milky Way features two distinct bars, one nestled within the other. The bar is delineated by red-clump stars (see also red giant), however, RR Lyr variables do not trace a prominent Galactic bar. The bar may be surrounded by a ring called the "5-kpc ring" that contains a large fraction of the molecular hydrogen present in the Milky Way, as well as most of the Milky Way's star formation activity. Viewed from the Andromeda Galaxy, it would be the brightest feature of the Milky Way.>>

[geckzilla]

Yes, what Art said, and for galaxies like NGC 2683 the stars stop becoming measurable when they blob together. If you can figure out what isovelocity contours and kinematics are you might be able to understand the paper linked to in the APOD description. Hmm, what are these mystical and arcane words? Astronomers are a little magical.

[Anthony Barreiro]

The other day on another forum, someone asked if there were any atheists who lent credence to astrology. Of course, the answer is “yes” (however few). If you look at my avatar, you’ll know what my astrological (tropical?) sign is. However, you’ll also know what I think of astrology.

Someone mentioned Chinese astrology, and I responded that if I had a Chinese background, I might use an image of Lepus, although it wouldn’t have the built-in clever pun. But I found myself wondering what constellation I would use if my background were Vietnamese.

Today’s APOD possibly answers that question.

Yes, Western astrology uses the tropical zodiac. And Tauruses never believe in astrology. I believe traditional Vietnamese culture used the Chinese system of dividing the sky into 28 lunar mansions, and the 12-year cycle of Jupiter through the zodiac to give us the 12 animals. I don't understand what flying saucers have to do with Vietnamese skylore, nor what connection you have to Vietnam.

[Chris Peterson]

If we can detect a bar in our own galay which is almost perfectly edge-on why is it hard to tell if near edge-on NGC 2683 has a bar?

Keep in mind that being barred isn't a binary option. There are galaxies that are obviously barred, there are galaxies that are obviously unbarred, and there is a range in between- including a region where it's pretty arbitrary what classification to apply.

[Chris Peterson]

A very slow clockwise tumble to this galaxy.

P.S. Comparing the mass of the galaxy, the rate of tumble, and the deflection of the leading and trailing edges will give the density of the medium the galaxy is tumbling in. Mathematicians, do your stuff.

Galaxies move in the intergalactic medium, which is far too tenuous to have any effect on the motion of any part of any galaxy. So there's nothing to see along the edges, and galaxies don't tumble at all.

[FloridaMike]

To a tumbleweed, the entire universe tumbles....

[Nitpicker]

Yes, what Art said, and for galaxies like NGC 2683 the stars stop becoming measurable when they blob together. If you can figure out what isovelocity contours and kinematics are you might be able to understand the paper linked to in the APOD description. Hmm, what are these mystical and arcane words? Astronomers are a little magical.

I haven't looked at the paper, but "isovelocity contours" sounds like redundant nomenclature. Contours of a velocity component are, by definition, iso-velocities, but maybe they are talking about velocity vector-potential, aka streamlines, showing the direction of motion (I'm probably wrong about what they are talking about). Kinematics is merely the study/description of motion without respect to the forces causing the motion. It is a general term.

[BDanielMayfield]

... you might be able to understand the paper linked to in the APOD description. Hmm, what are these mystical and arcane words?

Here’s what I think Geckzilla might mean by “mystical and arcane words”, with one exception:

We present optical long-slit and SparsePak Integral Field Unit emission line spectroscopy along with optical broadband and near-IR images of the edge-on spiral galaxy NGC 2683. We find a multi-valued, figure-of-eight velocity structure in the inner 45'' of the long-slit spectrum and twisted isovelocity contours in the velocity field. We also find, regardless of wavelength, that the galaxy isophotes are boxy. We argue that taken together, these kinematic and photometric features are evidence for the presence of a bar in NGC 2683. We use our data to constrain the orientation and strength of the bar.

Yes, I would say that that abstract is quite, well, abstract. Except for the word “boxy” which is quite understandable.

My apologies to Kuzio de Naray et al, the authors of Kinematic and Photometric Evidence for a Bar in NGC 2683.

Bruce

[Tumbleweed]

A very slow clockwise tumble to this galaxy.

P.S. Comparing the mass of the galaxy, the rate of tumble, and the deflection of the leading and trailing edges will give the density of the medium the galaxy is tumbling in. Mathematicians, do your stuff.

Galaxies move in the intergalactic medium, which is far too tenuous to have any effect on the motion of any part of any galaxy. So there's nothing to see along the edges, and galaxies don't tumble at all.

So you don't believe that the vast majority of the universe (Dark Matter) through which the galaxies move, or in which the galaxies move, is a reality?

Tumbling Galaxies: http://adsabs.harvard.edu/full/1984ApJ...286...53D

Tumbling Galaxies: http://ned.ipac.caltech.edu/level5/Marc ... la4_2.html

Tumbling Galaxies: http://www.researchgate.net/publication ... e_Sequence

Tumbling Galaxies: http://www.cosmicastronomy.com/motions.htm

Tumbling Galaxies: https://www.google.ca/search?q=tumbling ... B350%3B322

[Chris Peterson]

So you don't believe that the vast majority of the universe (Dark Matter) through which the galaxies move, or in which the galaxies move, is a reality?

Dark matter and ordinary matter are gravitationally bound. There's nothing to suggest that galaxies are moving through larger fields of dark matter. The exception is in galaxy clusters, where the entire cluster supports a dark matter halo. But I've seen nothing to suggest any morphological impact on the galaxies within those clusters (e.g. warped edges or tumbling).

And while galaxies might (and it's far from certain) show motion on more than a single axis, I wouldn't characterize them as tumbling, and I'd certainly not associate it with the influence of any intergalactic medium.