Travel the universe with Dr. Ethan Siegel as he answers the biggest questions of all
Over 300,000 light years long, a new record!
“Mozart’s music is like an X-ray of your soul — it shows what is there, and what isn’t.” –Isaac Stern
From 500 million light years away, the Chandra X-ray telescope has mapped out a 300,000 light year-long jet coming from the galaxy Pictor A.
A composite view of the galaxy Centaurus A, the nearest active galaxy to the Milky Way. Image credit: ESO/WFI (Optical); MPIfR/ESO/APEX/A.Weiss et al. (Submillimetre); NASA/CXC/CfA/R.Kraft et al. (X-ray).
Like many active galaxies, it’s powered by a supermassive black hole many millions or even billions of times the mass of our Sun.
A black hole more than a billion times the mass of the Sun powers this X-ray jet that’s many thousands of light years long. Image credit: NASA / Hubble / STScI / Wikisky tool, of the nearby giant elliptical galaxy, M87.
Some of these black holes accelerate and spit out infalling matter, giving rise to intense emissions.
X-ray emission from the jet in Pictor A. Image credit: “Deep Chandra observations of Pictor A”, M.J. Hardcastle et al. (2015), from http://arxiv.org/abs/1510.08392.
These span the spectrum from high-energy X-rays down into the low-energy radio.
The X-ray (B&W) and radio (red contours) emissions from the galaxy Pictor A. Image credit: “Deep Chandra observations of Pictor A”, M.J. Hardcastle et al. (2015), from http://arxiv.org/abs/1510.08392.
The radio lobes of gas provide a medium for these high-energy X-rays to interact with, creating an intense shock wave where the electrons exceed the speed of sound in the gas.
An annotated version of the X-ray/radio composite image of Pictor A, showing the counterjet, the Hot Spot and more. Image credit: X-ray: NASA/CXC/Univ of Hertfordshire/M.Hardcastle et al., Radio: CSIRO/ATNF/ATCA.
The “hot spot” at the end is the culmination of this jet, which is caused by electrons being continuously accelerated by the galaxy’s magnetic field.
Other explanations, such as high-energy electrons boosting a CMB photon into the X-ray, apply to some very distant galaxies, but are ruled out here.
The most distant X-ray jet in the Universe, from quasar GB 1428, located 12.4 billion light years from Earth. This jet comes from electrons heating CMB photons, but that mechanism is ruled out for Pictor A. Image credit: X-ray: NASA/CXC/NRC/C.Cheung et al; Optical: NASA/STScI; Radio: NSF/NRAO/VLA.
The lack of good optical or ultraviolet data mean we still don’t know whether this is a spiral or an elliptical galaxy.
The galaxy Pictor A in the optical (main) and the ultraviolet (inset), where its morphology is not discernible. Images credit: Digitized Sky Survey 2 (main); NASA/GALEX (inset).
Despite these unknowns, Pictor A possesses the largest single X-ray jet in the known Universe.
Mostly Mute Monday tells the story of a single astronomical phenomenon or object primarily in visuals, with no more than 200 words of text.
