by Ann » Fri Nov 12, 2021 5:34 am
Wow, that is a stunning portrait of the Triangulum Galaxy!
You will very rarely hear me complain that a picture is "too blue". Nevertheless, there is a lot of blue in this picture, and, well, I love it. Of course. There is also a lot of pink from Hα nebulas where brilliantly hot stars have just formed. What we really don't see in the "starry attire" of the galaxy is any yellow stuff! But the yellow stars are there - just look at the Hubble image below!
Well, that's the mysterious case of the color-changing galactic center, isn't it?
There can be no doubt that the small inner "bulge" of M33 - which probably isn't a bulge since it most likely isn't bulging, but you know what I mean - is yellow, today's APOD notwithstanding.
But today's APOD is so graceful! I love it! Look at the long graceful arms of our small Local Group spiral galaxy! And note the tiny, tiny little white nucleus. Astronomers say there is no central black hole there, at least not a supermassive one.
Wikipedia wrote:
The nucleus of this galaxy is an H II region, and it contains an ultraluminous X-ray source with an emission of 1.2 × 10
39 erg s
−1, which is the most luminous source of X-rays in the Local Group of galaxies. This source is modulated by 20% over a 106-day cycle. However, the nucleus does not appear to contain a supermassive black hole, as an upper limit of 3,000 solar masses is placed on the mass of a central black hole based upon the velocity of stars in the core region.
And then of course there is the giant site of star formation in M33,
NGC 604. But that is a matter for another day!
Ann
[float=left][attachment=0]M33_PS1_CROP_13x13[1].jpg[/attachment][/float]
[clear][/clear]
Wow, that is a stunning portrait of the Triangulum Galaxy! :D
You will very rarely hear me complain that a picture is "too blue". Nevertheless, there is a lot of blue in this picture, and, well, I love it. Of course. There is also a lot of pink from Hα nebulas where brilliantly hot stars have just formed. What we really don't see in the "starry attire" of the galaxy is any yellow stuff! But the yellow stars are there - just look at the Hubble image below!
[float=right][img3="The inner part of M33 that observed by Hubble, overlaid on a ground-based image. Credits: NASA, ESA, Digitized Sky Survey 2; acknowledgment: Davide De Martin"]https://www.nasa.gov/sites/default/files/styles/side_image/public/thumbnails/image/heic1901e.jpg?itok=6xNFRhlQ[/img3][/float][img3="The inner part of M33. Credits: NASA, ESA, and M. Durbin, J. Dalcanton and B. F. Williams (University of Washington)"]https://www.nasa.gov/sites/default/files/styles/full_width/public/thumbnails/image/heic1901a.jpg?itok=YLJUZyay[/img3]
[clear][/clear]
Well, that's the mysterious case of the color-changing galactic center, isn't it? 🕵️♀️ There can be no doubt that the small inner "bulge" of M33 - which probably isn't a bulge since it most likely isn't bulging, but you know what I mean - is yellow, today's APOD notwithstanding.
But today's APOD is so graceful! I love it! Look at the long graceful arms of our small Local Group spiral galaxy! And note the tiny, tiny little white nucleus. Astronomers say there is no central black hole there, at least not a supermassive one.
[quote][url=https://en.wikipedia.org/wiki/Triangulum_Galaxy#Structure]Wikipedia[/url] wrote:
The nucleus of this galaxy is an H II region, and it contains an ultraluminous X-ray source with an emission of 1.2 × 10[sup][size=85]39[/size][/sup] erg s[sup][size=85]−1[/size][/sup], which is the most luminous source of X-rays in the Local Group of galaxies. This source is modulated by 20% over a 106-day cycle. However, the nucleus does not appear to contain a supermassive black hole, as an upper limit of 3,000 solar masses is placed on the mass of a central black hole based upon the velocity of stars in the core region.[/quote]
[img3="NGC 604, giant site of star formation in M33. Photo: ESA/Hubble and NASA"]https://upload.wikimedia.org/wikipedia/commons/thumb/6/6a/M33.tif/lossy-page1-1254px-M33.tif.jpg[/img3]
[clear][/clear]
And then of course there is the giant site of star formation in M33, [url=https://en.wikipedia.org/wiki/NGC_604]NGC 604[/url]. But that is a matter for another day! :D
Ann