Hubble maps giant gas halo around Andromeda
Astronomers using the Hubble Space Telescope’s ability to observe in ultraviolet wavelengths have now mapped the giant halo of gas that surrounds the Andromeda galaxy 2.5 million light years away.
The work found that the halo appears to have both an inner and outer shell.
“We find the inner shell that extends to about a half million light-years is far more complex and dynamic,” explained study leader Nicolas Lehner of the University of Notre Dame in Indiana. “The outer shell is smoother and hotter. This difference is a likely result from the impact of supernova activity in the galaxy’s disk more directly affecting the inner halo.”
A signature of this activity is the team’s discovery of a large amount of heavy elements in the gaseous halo of Andromeda. Heavier elements are cooked up in the interiors of stars and then ejected into space—sometimes violently as a star dies. The halo is then contaminated with this material from stellar explosions.
The Andromeda galaxy, also known as M31, is a majestic spiral of perhaps as many as 1 trillion stars and comparable in size to our Milky Way. At a distance of 2.5 million light-years, it is so close to us that the galaxy appears as a cigar-shaped smudge of light high in the autumn sky. If its gaseous halo could be viewed with the naked eye, it would be about three times the width of the Big Dipper. This would easily be the biggest feature on the nighttime sky.
Though there is of course uncertainty here, this research is confirming earlier work, making its conclusions more robust.
A side note: Ultraviolet observations can only be done in space, as the atmosphere blocks it. Hubble I think is the only telescope in space right now with this capability. There used to be others, the most noteworthy of all being the International Ultraviolet Explorer, which functioned from 1978 to 1996 but was then decommissioned because neither NASA nor ESA were willing to fund its operation any longer.
No replacements have been launched because the budget for space astronomy has almost entirely been eaten by the overbudget and long delayed James Webb Space Telescope, with future budgets to be eaten similarly by the Roman.Space Telescope.
Readers!
I must unfortunately ask you for your financial support because I do not depend on ads and rely entirely on the generosity of readers to keep Behind the Black running. You can either make a one time donation for whatever amount you wish, or you sign up for a monthly subscription ranging from $2 to $15 through Paypal or $3 to $50 through Patreon.
Your support will allow me to continue covering science and culture as I have for the past twenty years, independent and free from any outside influence.
Your support is even more essential to me because I not only keep this site free from advertisements, I do not use the corrupt social media companies like Google, Twitter, and Facebook to promote my work. I depend wholly on the direct support of my readers.
You can provide that support to Behind The Black with a contribution via Patreon or PayPal. To use Patreon, go to my website there and pick one of five monthly subscription amounts, or by making a one-time donation. For PayPal click one of the following buttons:
If Patreon or Paypal don't work for you, you can support Behind The Black directly by sending your donation by check, payable to Robert Zimmerman, to
Behind The Black
c/o Robert Zimmerman
P.O.Box 1262
Cortaro, AZ 85652
Or you can donate by using Zelle through your bank. You will need to give my name and email address (found at the bottom of the "About" page). The best part of this electronic option is that no fees will be deducted! What you donate will be what I receive.
Astronomers using the Hubble Space Telescope’s ability to observe in ultraviolet wavelengths have now mapped the giant halo of gas that surrounds the Andromeda galaxy 2.5 million light years away.
The work found that the halo appears to have both an inner and outer shell.
“We find the inner shell that extends to about a half million light-years is far more complex and dynamic,” explained study leader Nicolas Lehner of the University of Notre Dame in Indiana. “The outer shell is smoother and hotter. This difference is a likely result from the impact of supernova activity in the galaxy’s disk more directly affecting the inner halo.”
A signature of this activity is the team’s discovery of a large amount of heavy elements in the gaseous halo of Andromeda. Heavier elements are cooked up in the interiors of stars and then ejected into space—sometimes violently as a star dies. The halo is then contaminated with this material from stellar explosions.
The Andromeda galaxy, also known as M31, is a majestic spiral of perhaps as many as 1 trillion stars and comparable in size to our Milky Way. At a distance of 2.5 million light-years, it is so close to us that the galaxy appears as a cigar-shaped smudge of light high in the autumn sky. If its gaseous halo could be viewed with the naked eye, it would be about three times the width of the Big Dipper. This would easily be the biggest feature on the nighttime sky.
Though there is of course uncertainty here, this research is confirming earlier work, making its conclusions more robust.
A side note: Ultraviolet observations can only be done in space, as the atmosphere blocks it. Hubble I think is the only telescope in space right now with this capability. There used to be others, the most noteworthy of all being the International Ultraviolet Explorer, which functioned from 1978 to 1996 but was then decommissioned because neither NASA nor ESA were willing to fund its operation any longer.
No replacements have been launched because the budget for space astronomy has almost entirely been eaten by the overbudget and long delayed James Webb Space Telescope, with future budgets to be eaten similarly by the Roman.Space Telescope.
I must unfortunately ask you for your financial support because I do not depend on ads and rely entirely on the generosity of readers to keep Behind the Black running. You can either make a one time donation for whatever amount you wish, or you sign up for a monthly subscription ranging from $2 to $15 through Paypal or $3 to $50 through Patreon.
Your support will allow me to continue covering science and culture as I have for the past twenty years, independent and free from any outside influence.
Your support is even more essential to me because I not only keep this site free from advertisements, I do not use the corrupt social media companies like Google, Twitter, and Facebook to promote my work. I depend wholly on the direct support of my readers.
You can provide that support to Behind The Black with a contribution via Patreon or PayPal. To use Patreon, go to my website there and pick one of five monthly subscription amounts, or by making a one-time donation. For PayPal click one of the following buttons:
If Patreon or Paypal don't work for you, you can support Behind The Black directly by sending your donation by check, payable to Robert Zimmerman, to
Behind The Black
c/o Robert Zimmerman
P.O.Box 1262
Cortaro, AZ 85652
Or you can donate by using Zelle through your bank. You will need to give my name and email address (found at the bottom of the "About" page). The best part of this electronic option is that no fees will be deducted! What you donate will be what I receive.
Readers: the rules for commenting!
No registration is required. I welcome all opinions, even those that strongly criticize my commentary.
However, name-calling and obscenities will not be tolerated. First time offenders who are new to the site will be warned. Second time offenders or first time offenders who have been here awhile will be suspended for a week. After that, I will ban you. Period.
Note also that first time commenters as well as any comment with more than one link will be placed in moderation for my approval. Be patient, I will get to it.