APOD: M104: The Sombrero Galaxy (2019 Mar 29)

Comments and questions about the APOD on the main view screen.
User avatar
APOD Robot
Otto Posterman
Posts: 5459
Joined: Fri Dec 04, 2009 3:27 am

APOD: M104: The Sombrero Galaxy (2019 Mar 29)

Post by APOD Robot » Fri Mar 29, 2019 4:06 am

Image M104: The Sombrero Galaxy

Explanation: The striking spiral galaxy M104 is famous for its nearly edge-on profile featuring a broad ring of obscuring dust lanes. Seen in silhouette against an extensive central bulge of stars, the swath of cosmic dust lends a broad brimmed hat-like appearance to the galaxy suggesting a more popular moniker, The Sombrero Galaxy. Hubble Space Telescope data have been used to to create this sharp view of the well-known galaxy. The processing results in a natural color appearance and preserves details often lost in overwhelming glare of M104's bright central bulge when viewed with smaller ground-based telescopes. Also known as NGC 4594, the Sombrero galaxy can be seen across the spectrum and is host to a central supermassive black hole. About 50,000 light-years across and 28 million light-years away, M104 is one of the largest galaxies at the southern edge of the Virgo Galaxy Cluster.

<< Previous APOD This Day in APOD Next APOD >>

User avatar
Ann
4725 Å
Posts: 13614
Joined: Sat May 29, 2010 5:33 am

Re: APOD: M104: The Sombrero Galaxy (2019 Mar 29)

Post by Ann » Fri Mar 29, 2019 5:11 am

Today's APOD is strikingly beautiful.

M104 in visual light. Photo: Lowell Observatory.
M104 in infrared light. Photo: Spitzer Space Telescope.






















M104 is a mysterious galaxy. In the picture at left, you can see how this galaxy got its name, "The Sombrero Galaxy". In old visual-light photographs, M104 really used to look like a hat. The huge bright bulge really looked like the crown of a hat, while the surrounding disk looked like a broad brim.

Infrared photography has revealed unexpected structures inside M104.
Elizabeth Howell of Space.com wrote:

Examination of the galaxy in recent years revealed that it had a sort of "split personality," NASA said on another website, showing that is a large elliptical galaxy that has a disk galaxy embedded inside of it. The reason this happened is still poorly understood.
Jason Major of Spitzer wrote:

In addition, Spitzer discerned that the flat disk within the galaxy is made up of two sections — an inner disk composed almost entirely of stars with no dust, and an outer ring containing both dust and stars.
...
Although it might seem that the Sombrero is the result of a collision between two separate galaxies, that’s actually not thought to be the case. Such an event would have destroyed the disk structure that’s seen today; instead, it’s thought that the Sombrero accumulated a lot of extra gas billions of years ago when the Universe was populated with large clouds of gas and dust. The extra gas fell into orbit around the galaxy, eventually spinning into a flattened disk and forming new stars.
As for today's APOD, one thing that makes it so beautiful is the colors of M104, including appreciable amounts of blue.

I must say, however, that I doubt the suggestion that there are many blue stars in M104 at all. NASA's now defunct ultraviolet space telescope GALEX photographed M104 and found very little ultraviolet light in it.

Check out this page. It shows you a GALEX poster of 196 galaxies, with ultraviolet-rich galaxies on the left side and ultraviolet-poor galaxies on the right side. Galaxies that are shown in blue are rich in hot stars, and yellow galaxies mostly lack them. (More specifically: Blue light in GALEX pictures means far ultraviolet light, emitted by hot stars, and yellow light means near ultraviolet light, emitted by modest intermediate-temperature stars like the Sun.)

You can download the poster from that page. WARNING!!! The small 56 KB picture is mostly useless, and the large one (21.3 MB!!!) takes forever to download, and it is so big that you lose your bearings. Also there are no captions identifying the galaxies, so you will have to download another big page to see a list of names of the galaxies.

For all of that, please take a look at the page I directed you to, which is quite safe to open. Even with the tiny sizes of the galaxies, you should be able to spot Centaurus A in the sixth row from the top, as number four from the right side. Cen A looks big and dramatic, with a blue-white dust lane curving dramatically over a yellow elliptical galaxy. Surely you can see it.

Now that you have identified Cen A, go one row down and one step to the right. That galaxy is M104. You may think twice about downloading the poster so that you can see M104 better, but take it from me: There is very little ultraviolet light in M104. And because there is so little ultraviolet light in M104, there are also very few hot main sequence or giant stars in M104. So you should probably think of the bluest parts of M104 in today's APOD as parts that are moderately rich in F-type stars like Procyon.

I'll try to attach the GALEX picture of M104 at the bottom of this post.

M104 GALEX.png
You do not have the required permissions to view the files attached to this post.
Color Commentator

Boomer12k
:---[===] *
Posts: 2691
Joined: Sun Apr 22, 2007 12:07 am

Re: APOD: M104: The Sombrero Galaxy (2019 Mar 29)

Post by Boomer12k » Fri Mar 29, 2019 9:34 am

Very good image... and you can see how sparse and thin the inner region is.

My 104 from May 2017... my focus wasn't so good.

:---[===] *
You do not have the required permissions to view the files attached to this post.

De58te
Commander
Posts: 584
Joined: Mon Sep 30, 2013 6:35 pm

Re: APOD: M104: The Sombrero Galaxy (2019 Mar 29)

Post by De58te » Fri Mar 29, 2019 10:23 am

Elizabeth Howell said, it is a large elliptical galaxy with a disk galaxy embedded inside of it. This confuses me because I think I see the disk surrounding the elliptical?? If it was embedded inside you wouldn't see the disc in front. Also, Ann said it takes forever to download the large image. It took me about 5 seconds. That's not too long a wait. You really need to get a faster internet speed. I think I get 5 MB a second and it costs less now than what I paid for 1 MB ten years ago. By the way that is a cool test for my internet speed. At 5 MB a second it would have taken just over 4 seconds to download 21 MB which is about what I got since I didn't really put a stop watch timer to it.

User avatar
orin stepanek
Plutopian
Posts: 8200
Joined: Wed Jul 27, 2005 3:41 pm
Location: Nebraska

Re: APOD: M104: The Sombrero Galaxy (2019 Mar 29)

Post by orin stepanek » Fri Mar 29, 2019 11:31 am

Sombrero' very beautiful galaxy! 8-) Reminds me of an overcooked pancake; but still wets my appetite! :wink:
Orin

Smile today; tomorrow's another day!

User avatar
Ann
4725 Å
Posts: 13614
Joined: Sat May 29, 2010 5:33 am

Re: APOD: M104: The Sombrero Galaxy (2019 Mar 29)

Post by Ann » Fri Mar 29, 2019 2:48 pm

De58te wrote: Fri Mar 29, 2019 10:23 am Elizabeth Howell said, it is a large elliptical galaxy with a disk galaxy embedded inside of it. This confuses me because I think I see the disk surrounding the elliptical?? If it was embedded inside you wouldn't see the disc in front. Also, Ann said it takes forever to download the large image. It took me about 5 seconds. That's not too long a wait. You really need to get a faster internet speed. I think I get 5 MB a second and it costs less now than what I paid for 1 MB ten years ago. By the way that is a cool test for my internet speed. At 5 MB a second it would have taken just over 4 seconds to download 21 MB which is about what I got since I didn't really put a stop watch timer to it.
M104 in infrared with an inner disk.
Photo: Spitzer Space Telescope.

Well, the disk Elizabeth Howell was talking about is really inside the spherical body, the elliptical galaxy. Take a look at the Spitzer infrared image of M104 at right. Can you see that there is a small, light blue disk inside the red ring of the galaxy? The red ring is the "brim" of the "sombrero hat", seen in infrared. It is the dust in this part of the Sombrero galaxy that looks red in the Spitzer image, while "pure" starlight looks blue. Can you see, too, that there is a darker blue ring surrounding the light blue disk? The dark blue ring almost looks like a gap between the inner disk and the outer, red-colored, dusty disk.

My computer also downloads the GALEX image pretty fast. But you see, I once posted that 21 MB GALEX image here at Starship Asterisk*, and people were really mad! Several complained that the picture took way too long to download. That is why I always post a warning these days before I ask people to download a large image.

Ann
Color Commentator

User avatar
Cousin Ricky
Science Officer
Posts: 456
Joined: Mon Aug 26, 2013 4:08 pm
Location: St. Thomas, U.S. Virgin Islands (+18.3, -64.9)

Re: APOD: M104: The Sombrero Galaxy (2019 Mar 29)

Post by Cousin Ricky » Fri Mar 29, 2019 4:38 pm

APOD Robot wrote: Fri Mar 29, 2019 4:06 am About 50,000 light-years across and 28 million light-years away, M104 is one of the largest galaxies at the southern edge of the Virgo Galaxy Cluster.
How is M104 part of a cluster that’s 50 million plus light years away when it’s only 28 million light years away? This has been asked before, but I don’t recall a resolution.

User avatar
Chris Peterson
Abominable Snowman
Posts: 18401
Joined: Wed Jan 31, 2007 11:13 pm
Location: Guffey, Colorado, USA

Re: APOD: M104: The Sombrero Galaxy (2019 Mar 29)

Post by Chris Peterson » Fri Mar 29, 2019 4:44 pm

Cousin Ricky wrote: Fri Mar 29, 2019 4:38 pm
APOD Robot wrote: Fri Mar 29, 2019 4:06 am About 50,000 light-years across and 28 million light-years away, M104 is one of the largest galaxies at the southern edge of the Virgo Galaxy Cluster.
How is M104 part of a cluster that’s 50 million plus light years away when it’s only 28 million light years away? This has been asked before, but I don’t recall a resolution.
M104 is not a member of the Virgo Cluster. It is simply positioned near it in the sky.
Chris

*****************************************
Chris L Peterson
Cloudbait Observatory
https://www.cloudbait.com

User avatar
neufer
Vacationer at Tralfamadore
Posts: 18805
Joined: Mon Jan 21, 2008 1:57 pm
Location: Alexandria, Virginia

South of the Ecliptic...down Corvus way.

Post by neufer » Fri Mar 29, 2019 7:59 pm

Click to play embedded YouTube video.
Chris Peterson wrote: Fri Mar 29, 2019 4:44 pm
Cousin Ricky wrote: Fri Mar 29, 2019 4:38 pm
APOD Robot wrote: Fri Mar 29, 2019 4:06 am
About 50,000 light-years across and 28 million light-years away,
M104 is one of the largest galaxies at the southern edge of the Virgo Galaxy Cluster.
How is M104 part of a cluster that’s 50 million plus light years away when it’s only 28 million light years away?
M104 is not a member of the Virgo Cluster.

It is simply positioned near it in the sky.
https://en.wikipedia.org/wiki/Sombrero_Galaxy wrote:
<<The Sombrero Galaxy lies within a complex, filament-like cloud of galaxies that extends to the south of the Virgo Cluster. However, it is unclear whether the Sombrero Galaxy is part of a formal galaxy group. Hierarchical methods for identifying groups, which determine group membership by considering whether individual galaxies belong to a larger aggregate of galaxies, typically produce results showing that the Sombrero Galaxy is part of a group that includes NGC 4487, NGC 4504, NGC 4802, UGCA 289, and possibly a few other galaxies. However, results that rely on the percolation method (i.e. the "friends-of-friends" method), which links individual galaxies together to determine group membership, indicate that either the Sombrero Galaxy is not in a group or that it may only be part of a galaxy pair with UGCA 287.>>
Art Neuendorffer

bls0326
Science Officer
Posts: 127
Joined: Tue Mar 26, 2013 10:18 pm
Location: USA, Texas, Amarillo

Re: APOD: M104: The Sombrero Galaxy (2019 Mar 29)

Post by bls0326 » Fri Mar 29, 2019 9:49 pm

Ann - Thanks for the GALEX image link. I downloaded both the images and the names files.

Brian