This composite image of the Whirlpool Galaxy and it’s nearby companion galaxy overlays radio astronomy data from the Very Large Array with optical data. The image in white shows how the galaxies appear to optical telescopes: one giant spiral galaxy with a smaller one hanging off an arm. The VLA sees a much bigger picture. The blue overlay reveals the the cast-off gases that were once in the outer spiral arms of these galaxies which have been pulled apart as the smaller galaxy has moved passed the larger one.
This video starts with a composite image of the Crab Nebula, a supernova remnant that was assembled by combining data from five telescopes spanning nearly the entire breadth of the electromagnetic spectrum: the Very Large Array, the Spitzer Space Telescope, the Hubble Space Telescope, the XMM-Newton Observatory, and the Chandra X-ray Observatory.
The video dissolves to the red-colored radio-light view that shows how a neutron star’s fierce “wind” of charged particles from the central neutron star energized the nebula, causing it to emit the radio waves. The yellow-colored infrared image includes the glow of dust particles absorbing ultraviolet and visible light. The green-colored Hubble visible-light image offers a very sharp view of hot filamentary structures that permeate this nebula. The blue-colored ultraviolet image and the purple-colored X-ray image shows the effect of an energetic cloud of electrons driven by a rapidly rotating neutron star at the center of the nebula.
This multi-colored haze is actually two colliding galaxy clusters that are forming a single object known as MACS J0416.1-2403 (or MACS J0416 for short). It’s located about 4.3 billion light-years from Earth. This image combines data from three different telescopes: the Hubble Space Telescope (showing the galaxies and stars), the Chandra X-ray Observatory (diffuse emission in blue), and the NRAO Very Large Array (diffuse emission in pink). Each telescope shows a different element of the cluster.
As with all galaxy clusters, MACS J0416 contains a significant amount of dark matter which leaves a detectable imprint in visible light by distorting the images of background galaxies. In this image the dark matter appears to align well with the blue-hued hot gas, suggesting that the two clusters have not yet collided. If the clusters had already merged, the dark matter and gas would have separated.
Image credit: NASA / ESA / CXC / NRAO-AUI-NSF /STScI / G. Ogrean (Stanford University)
This is Saturn, as seen by the Very Large Array (VLA) radio telescope. The bright disk of the planet gradually fades toward the edge, an effect called limb darkening. It’s caused by the gradual cooling moving outward in Saturn’s atmosphere. The rings are seen as emitters of energy outside the planet’s disk, but in front of the planet they absorb the radiation from the bright disk behind and appear as a dark band. That’s in contrast to their appearance in visible light where they reflect the incident sunlight. At radio wavelengths sunlight is much fainter, and we see the actual radio emissions from Saturn.
Hercules A, also known as 3C 348, lies around two billion light-years away. It is one of the brightest sources of radio emission outside our Galaxy. It’s the bright object at the middle of the frame, an elliptical galaxy. As seen in visible light by the Hubble Space Telescope it appears floating serenely in the inky blackness of space, but adding data from a radio telescope radically transforms the image. Jets of material can be seen billowing outwards from the galaxy when viewed at radio frequencies—jets that are completely undetectable in visible light. The image above combines data from the Very Large Array radio observatory in New Mexico with data from Hubble‘s Wide Field Camera 3.
The two jets are composed of hot, high-energy plasma that has been flung from Hercules A by a supermassive black hole lurking at the galaxy’s core. This black hole is roughly 2.5 billion times the mass of the Sun. That’s about a thousand times more massive than the black hole at the centre of the Milky Way.
Hercules A’s black hole accelerates the ejected material to nearly the speed of light, sending it flying out into intergalactic space. Eventually, the highly focused jets lose energy, slowing down and spreading out to form cloud-like blobs The multiple bright rings and knots seen within these blobs suggest that the black hole has sent out successive bursts of material. The jets stretch for around 1.5 million light-years, around 15 times the size of the Milky Way.
Seen in visible light and infrared, the galaxy known as M106 a a garden-variety spiral galaxy, but when it’s viewed at radio frequencies (purple) and x-rays (blue), additional arms appear. These are jets powered by matter falling into a massive black hole.