In a new study using data from the James Webb Space Telescope (JWST), Prof. Dasyra of the National and Kapodistrian University of Athens, Greece, and her team provided insights into how supermassive black holes affect galaxy evolution by driving interstellar gas out of galactic disks.
In a paper that was recently accepted for publication in The Astrophysical Journal, and is available on arXiv, the team presented cycle 1 JWST data of the nearby galaxy IC5063.
A supermassive black hole at the center of this fascinating nearby galaxy ejects jets, which are collimated beams of particles traveling at high velocities, near the speed of light. By employing JWST’s Mid-Infrared Instrument (MIRI), the researchers were able to capture high-resolution images and spectra from a region surrounding the center of IC5063 that spans a distance equivalent to ~1/3 of the distance between our sun and the center of our own galaxy.
One of the most striking outcomes of this research is the identification of more than 10 distinct regions with winds, nearly doubling the known areas where gas is being expelled from the galaxy’s nucleus following the impact of black-hole jets.
Some of these winds are moving at velocities that exceed what would be necessary to escape the galaxy’s gravitational pull—a result proving that black hole jets can delay star formation by depleting a galaxy from the gas that would be needed to collapse and form stars. These outflows also exhibit diverse structures and characteristics, such as differences in the temperature of the gas they entrain.
This study also sheds light on the past jet activity of IC5063. The researchers discovered gas in bow shocks, i.e., bow-shaped structures that form when jet particles plow through the interstellar medium at supersonic speeds, leading to the compression, heating, and acceleration of their surrounding gas. These shocks are analogous to the sonic booms produced by aircraft that exceed the sound speed in the Earth’s atmosphere.
The extent of the detected bow shocks is vast, spanning ~300 pc or 6 billion times the distance between the JWST and Earth. Surprisingly, their location is well beyond the region of the nucleus of IC5063 where the black hole jets are detected by their radio emissions. This finding indicates that jets may have interacted with the surrounding gas in the past and then faded away, in a recurrent activity of particle ejection from the vicinity of the supermassive black hole that continues to shape the galaxy today.
Intriguingly, the bow shocks were discovered thanks to their very bright molecular hydrogen (H₂) emission, reflecting the energy deposition from the jet to the dense gas. As the jets stir this gas, the associated turbulence and heating can both hinder and promote the collapse of clouds toward the birth of new stars.
Why does this matter? Over time, such phenomena can lead to significant changes in a galaxy’s structure. Studying them in galaxies like IC5063 gives scientists the opportunity to witness how black holes could have similarly altered the growth of galaxies in the past, during epochs when much larger quantities of gas existed in galaxies and the effect was more dramatic.
More information:
K. M. Dasyra et al, A case study of gas impacted by black-hole jets with the JWST: outflows, bow shocks, and high excitation of the gas in the galaxy IC5063, arXiv (2024). DOI: 10.48550/arxiv.2406.03218
Provided by
National and Kapodistrian University of Athens
Citation:
Webb observes winds driven by black hole jets in more than ten different regions of a nearby galaxy (2024, December 9)
