Tuesday, 13 January 2015

A New Year & New Results from the Hubble Space Telescope

Mural of  HST composite image of a section of M31, the Andromeda galaxy, on display at the AAS meeting. The galaxy's centre is at the left and spiral arms extend to the right.  Chris Gainor photo.

Every year just after New Year's Day, there is a flurry of news about astronomy that issues from the winter meeting of the American Astronomical Society. The 2015 AAS meeting took place last week in Seattle, and I attended as part of my work on the history of the Hubble Space Telescope.

This year marks the 25th anniversary of Hubble's launch, and HST is working as well as it ever has. So it was no surprise that there was no shortage of news relating to HST at the AAS meeting.

One was a re-release of the famous "Pillars of Creation" image that Hubble captured in 1995 of the Eagle Nebula. Today HST is equipped with better camera than it was twenty years ago, and the re-release included an image that covers a larger area in greater resolution than the 1995 version, and another haunting image in near infrared light.

The Space Telescope Science Institute and NASA also released the highest definition image ever taken of the Andromeda Galaxy, a gigantic composite image made up of 12,834 smaller HST images obtained over 39 months. A high-definition bandwidth-testing version can be downloaded from hubblesite.org (and the Eagle Nebula images can be found there too).

But to mark the publication of this composite image from the Panchromatic Hubble Andromeda Treasury (PHAT), a mural of the image was erected at the AAS meeting. The 61,000 light-year-long section of Andromeda was printed out at 150 light years per inch, and individual stars can be made out when one walks up to the mural, as shown in the image below.

Closeup of a small section of the mural based on the Andromeda HST composite image. Chris Gainor photo.

Andromeda is a large spiral galaxy that is only two million light years away from Earth, a short distance  on the galactic scale. Andromeda is a popular target for amateur astronomers like me, and in fact it can be seen with the naked eye from dark sky locations outside of cities.  One day in the distant future it will collide with our Milky Way galaxy. 

The composite image obtained by Hubble will be a valuable resource for years to come for astronomers studying the structure and contents of galaxies. Because  it is difficult for us to study the structure of our own galaxy in detail because we are inside it, high definition images of our neighbouring galaxy will be a most useful resource.

Investigators at the University of Washington have already called on citizen scientists to look through this imagery to search for star clusters as part of the Andromeda Project. More information on this effort is available at http://www.andromedaproject.org 

The images from the Eagle Nebula and Andromeda were only two of the many sets of results from Hubble data that were presented at the AAS. New Hubble data were used in, amongst other things, presentations on planets orbiting other stars, on clouds of gas blowing out from our Milky Way galaxy, and on Eta Carinae, the strange double star system visible from the southern hemisphere.

Perhaps the most exciting thing about events such as the AAS meeting is that HST is just one of the many telescopes on Earth and in space that are currently collecting new information that is revolutionizing our view of the universe we live in.

Hubble Space Telescope near infrared image of M16, the Eagle Nebula. Space Telescope Science Institute image.

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