A multifrequency view of the bent jet in J1924-2914. Image Credit: VLBA (Hunt et al. 2021), GMVA (Issaoun et al. 2019), EHT (Issaoun, Wielgus, et al. 2022).
The Event Horizon Telescope (EHT) has released new observations that are once again at the cutting edge of science. The team that gave us the first image of our very own supermassive black hole has now revealed the most detailed radio image of a blazer, J1924-2914.
A blazar, not to be confused with a bright dinner jacket, is an active supermassive black hole whose jet is being shot towards us. The EHT has delivered observations with unprecedented angular resolution: it can resolve structures within 3 light-years of the black hole. Not bad given the host galaxy is located over 4 billion light-years from us.
Published in The Astrophysical Journal, the achievement is based on data conducted during the original observation campaign in April 2017 that gave us the first-ever image of a black hole. The team studied structures just a few light-years in size to hundreds of light-years wide thanks to the combination of multiple observatories around the world acting as one Earth-sized telescope.
The observations have revealed that the jet is helically bent, like a spiral staircase of plasma erupting from the vicinity of the black hole. The angular resolution of these observations is equivalent to seeing an orange on the surface of the Moon from Earth.
“Our images constitute the highest angular resolution images of polarized emission from a quasar ever obtained,” lead author Sara Issaoun, NHFP Einstein Fellow at the Harvard & Smithsonian Center for Astrophysics in Cambridge, said in a statement.
“We see interesting details in the strongly polarized innermost core of the source; the morphology of the polarized emission is hinting at the presence of a twisted magnetic field structure.”
The emission of the blazar being polarized means that light is oscillating in a particular direction. This is caused by the presence of a powerful magnetic field.
The emission from J1924-2914 was also used in the momentous observations of Sagittarius A* the supermassive black hole at the center of the Milky Way, whose first picture was shared by the EHT just a few months ago.
“J1924-2914 is our main calibrator for the Sagittarius A* studies – this means that we needed to understand it really well, so that we could use this knowledge to improve total intensity and polarimetric calibration of the more difficult, time-variable source that is Sagittarius A*” explain co-lead Maciek Wielgus, from the Max Planck Institute for Radio Astronomy.
There are many more observations that have been conducted by the EHT over the last few years, so there is much more to come; they are just getting started with this incredible science.