Travel the universe with Dr. Ethan Siegel as he answers the biggest questions of all
How colliding galaxy clusters emit the most spectacular fireworks, if only you look beyond what your eyes can see!
“Every single time you make a merger, somebody is losing his identity. And saying something different is just rubbish.” –Carlos Ghosn
By collecting huge amounts of light from space, the Hubble Space Telescope discovers and images the Universe’s most massive, distant galaxy clusters.
Image credit: NASA / STScI, of cluster MACS J0717.5+3745 in the optical, courtesy of Hubble Frontier Fields.
Yet there’s more to these objects than merely stars, as revealed by visible light.
Image credit: NASA / STScI, of cluster MACS J0416.1–2403 in the optical, courtesy of Hubble Frontier Fields.
At the high-end of the energy spectrum, X-rays, as imaged by NASA'sChandra observatory, reveal superheated gas and plasma.
Image credit: NASA/CXC/SAO/G.Ogrean et al., of galaxy cluster MACS J0717.5+3745 in the X-ray, courtesy of Chandra.
When extremely high-velocity gas clouds collide, the density and temperature both spike, resulting in the emission of energetic X-rays.
Image credit: NASA/CXC/SAO/G.Ogrean et al., of galaxy cluster MACS J0416.1–2403 in the X-ray, courtesy of Chandra.
At the other end of the spectrum, low-energy emissions appear in the radio, as revealed by the Very Large Array here on Earth.
Image credit: NRAO/AUI/NSF, of galaxy cluster MACS J0416.1–2403 in the radio, with data from the Very Large Array (VLA).
While cluster MACS J0416.1–2403 (above, in the radio) showcases a simple collision in the early stages between two large galaxy clusters, MACS J0717.5+3745 (below) is much more complicated.
Image credit: NRAO/AUI/NSF, of galaxy cluster MACS J0717.5+3745 in the radio, with data from the Very Large Array (VLA).
With a total of four identified galaxy clusters colliding at once, this is one of the largest cosmic trainwrecks ever discovered.
Images credit: X-ray: NASA/CXC/SAO/G.Ogrean et al.; Optical: NASA/STScI; Radio: NRAO/AUI/NSF, of merging galaxy cluster in MACS J0717.5+3745.
By combining observations from all three wavelengths, astronomers can better understand matter’s evolution and distribution.
Images credit: X-ray: NASA/CXC/SAO/G.Ogrean et al.; Optical: NASA/STScI; Radio: NRAO/AUI/NSF, of merging galaxy cluster in MACS J0416.1–2403.
The final step will be to introduce gravitational lensing data.
Images credit: X-ray: NASA/ CXC/UVic./A.Mahdavi et al. Optical/Lensing: CFHT/UVic./A.Mahdavi et al. (top left); X-ray: NASA/CXC/UCDavis/W.Dawson et al.; Optical: NASA/STScI/UCDavis/ W.Dawson et al. (top right); ESA/XMM-Newton/F. Gastaldello (INAF/IASF, Milano, Italy)/CFHTLS (bottom left); X-ray: NASA, ESA, CXC, M. Bradac (University of California, Santa Barbara), and S. Allen (Stanford University) (bottom right). These four separate groups and clusters all show the separation between dark matter (blue) and normal matter (pink), where gravitational lensing and X-ray data are presented for the same colliding clusters.
By mapping starlight, X-rays, radio waves and mass, we’ll better comprehend how the largest structures grew and evolved in the Universe.
Mostly Mute Monday tells the story of a single astronomical phenomenon or object in pictures and other visuals, with no more than 200 words of text.
