The Young Astronomers
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The Eagle Nebula is one of the most well known regions in the universe having been snapped many times over the years by several telescopes including Hubble.
The latest images of the region come from the ESA’s Hershel Infrared Space Observatory and the XXM-Newton X-ray Observatory.
The Eagle Nebula seen by Hershel and XXM-Newton Credits: far-infrared: ESA/Herschel/PACS/SPIRE/Hill, Motte, HOBYS Key Programme Consortium; X-ray: ESA/XMM-Newton/EPIC/XMM-Newton-SOC/Boulanger
This image spans approximately 75 light years across the entirety of the nebula.
This image is a combination of data from both telescopes of the dense central region of the nebula. We can learn more about the information the image displays if we separate the data from each observatory, first lets have a look at the XXM-Newton X-ray data.
XXM data of the Eagle Nebula Credits: ESA/XMM-Newton/EPIC/XMM-Newton-SOC/Boulanger
Each individual dot on the image is an X-ray source with the various colours indicating the energy of the X-rays being emitted by the source, red being the lowest energy (0.3-1keV) working up through medium energy sources shown in green (1-2keV) to the highest energy sources displayed in blue (2-8keV).
The XXM was observing the area to help determine the source of the Eagle Nebula’s strong emission. One theory suggests that a hidden supernova remnant could be supplying the nebula with large quantities of energy whilst remaining obscured by the nebula’s dense cloud. To help determine if this theory is valid the XXM is scouring the area in an attempt to detect any sign of a faint X-ray emission extending from the central region. The scientists believe that if the XXM doesn’t detect any more emitting material than has already been identified by previous searches using Sptizer and Chandra this will be strong support of the hidden SNR explanation.
Now lets examine the Hershel data:
Hershel's view of the Eagle Nebula Credits: ESA/Herschel/PACS/SPIRE/Hill, Motte, HOBYS Key Programme Consortium
This displays the nebula in infra red wavelengths with 70 microns displayed in blue, 160 microns in green (both of these wavelengths were captured using filters in the PACS – Photodetector Array Camera - instrument) and finally 250 microns in red(images by SPIRE - Spectral and Photometric Imaging Receiver).
All these wavelengths are associated with very cold gas, indeed any gas displayed in blue here is just 40K above absolute zero down to that displayed in red which is a chilly 10K.
The twisted gas tendrils are still collapsing and will continue to form the next generation of stars for quite some time yet before the nebula finally disperses. Perhaps the most famous region within the nebula are the ‘Pillars of Creation’ which are in the above images which can be viewed just below the central point in the image (the eagle for which the nebula is named is located half way up the image on the left hand side, with its head pointing inwards). Indeed the Pillars are the central feature in one of the most recognisable image in all of astronomy:
The Pillars of Creation as seen by Hubble Credits: NASA/ESA/STScI, Hester & Scowen (Arizona State University)
The image was taken by Hubble in visible light using filters that isolate emission from excited hydrogen (Hα), singly ionised sulphur (SII) and doubly ionised oxygen (OIII). For scale, the tallest pillar is approximately four light years in height.
Now if we look at the same region in the infra red part of the spectrum (this time the data is provided by the ESO‘s, VLT’s ANTU telescope using the ISAAC instrument – yes that is quite a lot of acronyms), it looks completely different.
The Pillars of Creation as seen by ANTU Credits: VLT/ISAAC/McCaughrean & Andersen/AIP/ESO
At these wavelengths all but the densest regions of the Pillars are virtually transparent allowing us to gaze in wonder at the clumps of stars forming at the tips.
I leave you with this composite image, containing X-ray, visible and infra red data, enjoy.
Composite image of the Eagle Nebula Credits: far-infrared: ESA/Herschel/PACS/SPIRE/Hill, Motte, HOBYS Key Programme Consortium; ESA/XMM-Newton/EPIC/XMM-Newton-SOC/Boulanger; optical: MPG/ESO; near-infrared: VLT/ISAAC/McCaughrean & Andersen/AIP/ESO
You can read more about this fantastic collection of images here.
Today’s image comes from the ESO’s Very Large Telescope (VLT) and displays the Omega Nebula in astonishingly fine detail.
The Omega Nebula Credit: ESO
It is well worth clicking the image for a larger version.
The Omega nebula has been called many things since its discovery, The Swan Nebula, The Horseshoe Nebula. It was first discovered in 1745 by Swiss astronomer Philippe Loys de Chéseaux and was entered into Charles Messier’s famous catalogue in 1764 as Messier 17.
It is located between 5000 and 6000 light years from Earth towards the centre of the Milky Way – The constellation Sagittarius.
The gas clouds are ionised by an open cluster of stars within the nebula, giving it the characteristic red and pink hues of excited hydrogen.
The enitrilty of the nebula is calculated to contain about 800 solar masses and is around 15 light years across
You can read more about the image here.
The galaxy cluster Abell 2052 is in a bit of a swirl.
Abell 2052 Credit: X-ray: NASA/CXC/BU/E.Blanton; Optical: ESO/VLT
The cluster is located at 489 million light years from Earth (z=0.03549)[1] in the direction of the constellation Serpens – The Serpent. Abell 2052 contains many galaxies with the brightest being UGC 9799, that also has a Seyfert 2 class AGN.[2]
UGC 9799 Credit: SDSS
The main image is a combination of X-ray data obtained by NASA’s Chandra Space Observatory and optical data from the ESO’s VLT.
X-ray data is displayed in blue, and shows hot gas at temperatures of around 30 million Kelvin, optical information is displayed in gold.
The large spiral of this superheated material in the centre of the image, which spans over one million light years in reality, was produced when a smaller galaxy cluster collided with the larger main cluster, throwing gas and dust outwards whilst heating it.
The smaller cluster passed through the main cluster several times under the action of gravity, with a spiral pattern being formed as the collisions were off centre – a perfectly lined up series of collisions would have produced a collisional ring.
The disturbance of the material has several effects on the galaxies:
- Cooler, denser gas is thrown outwards – this limits the ability of the material left in the core to cool and contract, thus limiting star formation
- Heavier elements such as Iron, Nitrogen and Oxygen are distributed throughout the region perhaps helping to stimulate the production of planets, and further down the line, life
You can read more here
[1] A description of how to interpret the z variable is pending. The distance estimate used in the post was calculated using WolframAlpha
[2] A detailed explanation on the various types of AGN is pending. Data for UGC 9799 was obtained using SIMBAD
This week’s image is of two galaxies located around 50 million light years from Earth in the direction of the Zodiac constellation Virgo – The Virgin
NGC 4438 and NGC 4435 Credit: ESO/Gems project
Nicknamed ‘The Eyes’ due to their appearance through an medium sized telescope, NGC 4438 (top) and NGC 4435 (bottom right-hand corner) are in reality a pair of interacting galaxies sitting about 100,000 light years apart.
NGC 4435 has had virtually all gas and dust stripped from its grasp. Astronomers believe this is partially explained by a collision it suffered with Messier 86 (not visible in this image) around 100 million years ago. The incriminating evidence for this takes the form of tendrils of ionised hydrogen linking the two. Pointing to a close gravitational attraction teasing out large volumes of gas from the pair helping to explain the barren nature of NGC 4435.
NGC 4438 on the other hand is rich in both gas and dust, highlighted by its intricate dust lane. NGC 4438 and NGC 4435 had a close gravitational encounter 100,000 years ago, passing just 16,000 light years from each other. This disrupted the once ordered spiral structure of NGC 4438 and removed any free material NGC 4435 had been clinging on to.
The image was produced as part of the ESO’s Gems project for public outreach, using data obtained from the VLT’s FORS2 instrument.
You can read more here.
As one of the most recognised galaxy groups in the sky the Leo Triplet (a trio of interacting galaxies) has been the subject of many beautiful images over the years, though few compare to this stunning new image from the ESO.
The Leo Triplet Credit: ESO/INAF-VST/OmegaCAM. Acknowledgement: OmegaCen/Astro-WISE/Kapteyn Institute
At around 35 million light years from Earth, in the direction of, you guessed it, Leo – The Lion. Such a distance my seem large though it is a stone’s throw on terms of the universe.
All three members of the Triplet are in fact spiral galaxies not dissimilar to our own Milky Way. They each appear so different as they are visible to us from different angles. NGC 3628 is seen edge on at the left of the image whereas M 65 (in the top right hand corner) and M66 (in the bottom right) are closer to being face on and so allow us to peer at their spiral structures unhindered.
The image also contains many other galaxies that lie much further away from us. Along with many stars that lie within our own Milky Way as well as a few asteroid streaks produced by small objects in our Solar System.
The image was captured using the ESO’s VLT Survey Telescope (sometimes shortened to VST), it large field of view (twice the area of the full moon) allows it so see large tracts of the sky at once making it a valuable tool for astronomers. One of its objectives is to search for faint objects such as Brown Dwarfs and Black Holes within the Milky Way’s halo, objects normally to small and dim to be picked out but can be identified through gravitational microlensing. It will also peer deep into the universe to help expand our knowledge of the illusive dark matter.
You can read more here
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