Starship Asterisk*

M51: X-Rays from the Whirlpool

Explanation: What if we X-rayed an entire spiral galaxy? This was done (again) recently by NASA's Chandra X-ray Observatory for the nearby interacting galaxies known as the Whirlpool (M51). Hundreds of glittering x-ray stars are present in the above Chandra image of the spiral and its neighbor. The image is a conglomerate of X-ray light from Chandra and visible light from the Hubble Space Telescope. The number of luminous x-ray sources, likely neutron star and black hole binary systems within the confines of M51, is unusually high for normal spiral or elliptical galaxies and suggests this cosmic whirlpool has experienced intense bursts of massive star formation. The bright cores of both galaxies, NGC 5194 and NGC 5195 (right and left respectively), also exhibit high-energy activity. In this false-color image where X-rays are depicted in purple, diffuse X-ray emission typically results from multi-million degree gas heated by supernova explosions.

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Great APOD.

I nearly missed the hover image of visible light, though. I was scouring the links before I thought to hover over the image.

This is also a good example of an object where it makes sense (IMHO) to rotate its image so that North is left (as in this APOD), not up (as is conventional and as is presented on the Chandra website). With North left, the image is in landscape format, which better suits most computer screens.

Except for persons using their screens in vertical format.

geckzilla wrote:Except for persons using their screens in vertical format.

Yes, there are always a few weirdos and other tablet/phone viewers. (Calling them "persons" makes you sound like a cop. I'm not sure I'd call it a crime.)

I had an English teacher who insisted it was wrong to use people as the plural form of person.

I had a French teacher with a thick Scottish accent. No one can understand me if I try to speak French (including my French wife and inlaws).

geckzilla wrote:I had an English teacher who insisted it was wrong to use people as the plural form of person.

To me, people is more of a collective noun, while persons indicates a group of individual entities.

bystander wrote:

geckzilla wrote:I had an English teacher who insisted it was wrong to use people as the plural form of person.

To me, people is more of a collective noun, while persons indicates a group of individual entities.

A people of persons?

APOD Robot wrote:Hundreds of glittering x-ray stars are present in the above Chandra image of the spiral and its neighbor.

But back on topic (sort of) ... I take it that these x-rays glitter and not twinkle, because they are absorbed by the atmosphere. Or maybe the editors just have a soft spot for these soft x-rays. I can't imagine hard x-rays being described as glittering. Or perhaps I'm just not romantic enough.

Nitpicker wrote:Great APOD.

I nearly missed the hover image of visible light, though. I was scouring the links before I thought to hover over the image.

Thanks, Nitpicker, me too! This is a GREAT APOD. I was lucky to work with Herb Friedman in the early X-ray days. What a thrill to see this fabulous image!

Nitpicker wrote:

APOD Robot wrote:
Hundreds of glittering x-ray stars are present in the above Chandra image of the spiral and its neighbor.

I take it that these x-rays glitter and not twinkle, because they are absorbed by the atmosphere. Or maybe the editors just have a soft spot for these soft x-rays. I can't imagine hard x-rays being described as glittering. Or perhaps I'm just not romantic enough.

Hard x-rays gleam:
--------------------------------------------------------
Gleam, v. i. [OE. glem, gleam, AS. glæm, prob. akin to E. glimmer, and perh. to Gr. warm, to warm.] To shoot or dart, as rays of light.

• 1. To shine; to cast light.
  2. To flash; to spread a flood of light.
  3. Among falconers, to disgorge filth, as a hawk.

--------------------------------------------------------
Glitter, v. i. [OE. gliteren; akin to Sw. glittra, Icel. glitra, glita, AS. glitenian, OS. glītan, OHG. glīzzan, G. gleissen, Goth. glitmunjan, and also to E. glint, glisten, and prob. glance, gleam.]

• 1. To sparkle with light; to shine with a brilliant and broken light or showy luster; to gleam; as, a glittering sword.
  
  2. To be showy, specious, or striking, and hence attractive; as, the glittering scenes of a court.

--------------------------------------------------------
Twinkle, v. i. [OE. twinklen, AS. twinclian; akin to OE. twinken to blink, wink, G. zwinken, zwinkern, and perhaps to E. twitch.]

• 1. To open and shut the eye rapidly; to blink; to wink.
  • The owl fell a moping and twinkling. L' Estrange.
  2. To shine with an intermitted or a broken, quavering light; to flash at intervals; to sparkle; to scintillate.
  • These stars [do] not twinkle when viewed through telescopes that have large apertures. Sir I. Newton.

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What I find interesting is some, in the upper left, are outside the galactic disc....pulled away by the passing of the other galaxy....and I would expect increased star formation as gas and dust are more gravitationally agitated...

It seems that some would be Supernova Remnants then....and it seems to have many...the light dims but the Radiation Lingers....

Awesome to put the two images together.

:---[===] *

It makes sense that a galaxy with episodes of intense starburst activity also has experienced lots of supernovae. Other galaxies that have had a high rate of supernovae such as NGC 6946 and M83 also have a lot of HII regions and emission nebulae.

The shape, luminosity distribution and color of M51 is fairly unusual. It is no coincidence that M51 was the first galaxy that was found to be spiral in shape.

When a galaxy has such well-formed, bright and blue arms, it is no surprise that the galaxy has been affected by tidal forces for a long time and, presumably, has undergone repeated episodes of high-mass star formation. Then it is no wonder that it has formed a lot of black holes and neutron stars, either.

On the other hand, the star forming days of NGC 5195 are long past. Most likely it did form a lot of stars when it first interacted with M51, and black hole remnants of those once mighty blue stars now pump out X-rays from all over the luminous bulge and beyond from this small yellow galaxy.

Ann

geckzilla wrote:I had an English teacher who insisted it was wrong to use people as the plural form of person.

Some English teachers are like that.

Spectacular. What a wonderful Universe!

I watc hed a video of a person claiming to create x-rays using a vacuum tube. Isn't that a little bit on the dangerous side for all you know, what else is being created in that vacuum.

Two great images in one APOD. Thank you!

geckzilla wrote:I had an English teacher who insisted it was wrong to use people as the plural form of person.

OK people, everyone, please take a seat on the right. Now will the following persons, please move the the seats on the left.

Ann wrote:The shape, luminosity distribution and color of M51 is fairly unusual. It is no coincidence that M51 was the first galaxy that was found to be spiral in shape.

When a galaxy has such well-formed, bright and blue arms, it is no surprise that the galaxy has been affected by tidal forces for a long time and, presumably, has undergone repeated episodes of high-mass star formation. Then it is no wonder that it has formed a lot of black holes and neutron stars, either.

On the other hand, the star forming days of NGC 5195 are long past. Most likely it did form a lot of stars when it first interacted with M51, and black hole remnants of those once mighty blue stars now pump out X-rays from all over the luminous bulge and beyond from this small yellow galaxy.

Ann

One of the reasons that M51 was one of the first galaxies where spiral structure was detected is also due to its brightness.

starsurfer wrote:

Ann wrote:The shape, luminosity distribution and color of M51 is fairly unusual. It is no coincidence that M51 was the first galaxy that was found to be spiral in shape.

When a galaxy has such well-formed, bright and blue arms, it is no surprise that the galaxy has been affected by tidal forces for a long time and, presumably, has undergone repeated episodes of high-mass star formation. Then it is no wonder that it has formed a lot of black holes and neutron stars, either.

On the other hand, the star forming days of NGC 5195 are long past. Most likely it did form a lot of stars when it first interacted with M51, and black hole remnants of those once mighty blue stars now pump out X-rays from all over the luminous bulge and beyond from this small yellow galaxy.

Ann

One of the reasons that M51 was one of the first galaxies where spiral structure was detected is also due to its brightness.

Yes, that's what I meant when I talked about the luminosity distribution of M51. I meant that its arms are very bright as galactic spiral arms go.

Ann