Hello everyone,
We don't usually relay our images in the forum, but we like this one so much that we're making an exception, hoping that it will allow as many people as possible to see it.
After all, it's not every day that an amateur astro image allows us to indulge in astrophysical or even cosmological considerations!
So this is our image of the "Cheshire cat", an object that allows us to travel to distances that are truly considerable, measured in billions of light-years:
https://astrob.in/nxqwzp/0/
Observable in Ursa Major constellation, the "Cheshire Cat" is a small galaxy cluster dominated by two very luminous and massive elliptical galaxies, surrounded by several arcs that give it its characteristic physiognomy.
The cluster's total mass is estimated at around 3.3 × 10^13 M⊙, i.e. 10 times more matter than our entire Local Galactic Group, but condensed into a volume whose radius is barely greater than the distance between the Milky Way and the Large Magellanic Cloud.
As predicted by Einstein's theory of general relativity, this great concentration of mass causes a deformation of space-time, whose curvature then acts like a "gravitational lens", distorting objects in the background while increasing their luminosity, enabling us to see objects that would otherwise be inaccessible.
[Note : The masses, distances and cosmological elements quoted here are taken from or based on the following article: [url]https://arxiv.org/pdf/1505.05501
Calculations were made using the following tool: https://astro.ucla.edu/~wright/DlttCalc.html (with cosmological parameters: Ho = 69.6 / OmegaM = 0.286).
Distances are expressed in terms of light time travel, but the redshift value (z) is less open to interpretation...
The enlarged version has been processed with 2x drizzle to preserve as much detail as possible.]
In this image, 3 arcs are visible (a 4th, fainter and visible in the Hubble telescope image, could not be detected). These arcs have no "physical" existence: they are distorted visions of galaxies located behind the "lens", "gravitational mirages".
While the cluster of galaxies is already located at the considerable distance of 4.5 billion light-years (z=0.43), the distorted galaxies visible in the form of arcs are even further away... and here we touch on totally insane cosmological dimensions (for amateur astronomers at least), since the "nearest" is 7.5 billion light-years away (z=0.96) and the "farthest"... 11.4 billion light-years (z=2.8)!
Here is the reference image of this object, obtained with the Hubble Space Telescope:
Note that the slight difference in redshift between the two giant "eye" galaxies corresponds to a speed difference of 1,800 km s-1. Astronomers predict that these two galaxies will collide and merge within the next billion years.
This object is obviously an atypical and difficult target: the "cat" as a whole has an apparent dimension of 23 arc-seconds (i.e. barely more than Saturn at opposition...) and the magnitude of the "eyes" is 22, while the arcs are even smaller... Nevertheless, we managed to highlight the 3 brightest arcs, with even a few "details" inside (essentially differences in brightness).
Nevertheless, we managed to highlight the 3 brightest arcs, with even a few "details" inside (essentially differences in brightness).
An image that gives us a vertigo that we hope is contagious! 🙂
We hope you'll find this little presentation interesting!
Team OURANOS
Jean-Baptiste Auroux, Mathieu Guinot, Jean-Claude Mario & Matthieu Tequi.
We don't usually relay our images in the forum, but we like this one so much that we're making an exception, hoping that it will allow as many people as possible to see it.
After all, it's not every day that an amateur astro image allows us to indulge in astrophysical or even cosmological considerations!
So this is our image of the "Cheshire cat", an object that allows us to travel to distances that are truly considerable, measured in billions of light-years:
https://astrob.in/nxqwzp/0/
Observable in Ursa Major constellation, the "Cheshire Cat" is a small galaxy cluster dominated by two very luminous and massive elliptical galaxies, surrounded by several arcs that give it its characteristic physiognomy.
The cluster's total mass is estimated at around 3.3 × 10^13 M⊙, i.e. 10 times more matter than our entire Local Galactic Group, but condensed into a volume whose radius is barely greater than the distance between the Milky Way and the Large Magellanic Cloud.
As predicted by Einstein's theory of general relativity, this great concentration of mass causes a deformation of space-time, whose curvature then acts like a "gravitational lens", distorting objects in the background while increasing their luminosity, enabling us to see objects that would otherwise be inaccessible.
[Note : The masses, distances and cosmological elements quoted here are taken from or based on the following article: [url]https://arxiv.org/pdf/1505.05501
Calculations were made using the following tool: https://astro.ucla.edu/~wright/DlttCalc.html (with cosmological parameters: Ho = 69.6 / OmegaM = 0.286).
Distances are expressed in terms of light time travel, but the redshift value (z) is less open to interpretation...
The enlarged version has been processed with 2x drizzle to preserve as much detail as possible.]
In this image, 3 arcs are visible (a 4th, fainter and visible in the Hubble telescope image, could not be detected). These arcs have no "physical" existence: they are distorted visions of galaxies located behind the "lens", "gravitational mirages".
While the cluster of galaxies is already located at the considerable distance of 4.5 billion light-years (z=0.43), the distorted galaxies visible in the form of arcs are even further away... and here we touch on totally insane cosmological dimensions (for amateur astronomers at least), since the "nearest" is 7.5 billion light-years away (z=0.96) and the "farthest"... 11.4 billion light-years (z=2.8)!
Here is the reference image of this object, obtained with the Hubble Space Telescope:
Note that the slight difference in redshift between the two giant "eye" galaxies corresponds to a speed difference of 1,800 km s-1. Astronomers predict that these two galaxies will collide and merge within the next billion years.
This object is obviously an atypical and difficult target: the "cat" as a whole has an apparent dimension of 23 arc-seconds (i.e. barely more than Saturn at opposition...) and the magnitude of the "eyes" is 22, while the arcs are even smaller... Nevertheless, we managed to highlight the 3 brightest arcs, with even a few "details" inside (essentially differences in brightness).
Nevertheless, we managed to highlight the 3 brightest arcs, with even a few "details" inside (essentially differences in brightness).
An image that gives us a vertigo that we hope is contagious! 🙂
We hope you'll find this little presentation interesting!
Team OURANOS
Jean-Baptiste Auroux, Mathieu Guinot, Jean-Claude Mario & Matthieu Tequi.
