This is an artistic depiction of multiphase AGN-powered winds, demonstrating the diverse stages and scales at play during an outflow. The wind spreads from the core engine (< 1 pc; a), via the encompassing ISM (1 pc–1 kpc; b), extending to the perimeters of the host galaxy (> 10 kpc; c). The SUBWAYS project aims to study the outflow at its inception phase, during which the gas is extremely ionized and the existence of rapidly moving matter can be unveiled in X-rays. (Figure adapted from Cicone et al. 2018, Nat. As. 2, 176). Credit: University of Bologna
Named “UFOs” – but unrelated to extraterrestrial life – these are ultra-fast outflows: cosmic winds originating from the vicinity of supermassive black holes and accelerating nearly at light speed. An international team of researchers has delved into this somewhat mysterious event, in search of these gas discharges which are key to comprehending the regulating mechanisms of active-phase supermassive black holes.
The research initiative, SUBWAYS (SUper massive Black hole Winds in the x-rAYS), has published its initial findings in two papers in the Astronomy & Astrophysics journal. The first paper, primarily based on data gathered by the ESA’s XMM-Newton space telescope, is led by academics from the University of Bologna and INAF.
The researchers analyzed 22 active galactic nuclei (AGN), the areas encircling supermassive black holes at the center of galaxies. These nuclei radiate massive amounts of energy across the entire electromagnetic spectrum when the black holes are active. The study found that approximately 30% of the AGN inspected host space winds reaching speeds between 10% and 30% of the speed of light.
“These findings permit us to assert with more confidence that a substantial number of active galactic nuclei house ultra-fast winds known as UFOs,” explains Marcella Brusa, professor at the University of Bologna and INAF associate, and the coordinator of the SUBWAYS project. “We confirmed that the force of these gas outflows is sufficient to substantially modify their galaxies’ ecosystems.”
There exists a profound reciprocal relationship between a supermassive black hole and its surrounding galaxy that significantly influences their formation and evolution. The mechanisms that drive this mutual interaction are yet not fully understood, but one critical component could be the ultra-fast winds emitted by active galactic nuclei. These potent outflows occur when part of the gas in the accretion disk is propelled outward, transferring matter and energy to the interstellar space, which plays a crucial role in controlling star formation.
To identify UFOs, scientists analyze X-ray band-emitted spectra, looking for absorption caused by highly ionized elements like iron. This is due to the extreme temperatures – reaching tens of millions of degrees – generated near supermassive black holes. Armed with this knowledge, SUBWAYS scientists successfully procured 1.6 million seconds of observation time (more than eighteen days) with the ESA XMM-Newton X-ray Space Telescope. They scrutinized 17 active galactic nuclei in the relatively local universe (ranging about 1.5 to 5 billion light-years away), and added data from 5 more AGN from prior observations.
“These observations have provided new independent verification of the presence of highly ionized matter being ejected from the innermost regions of active galactic nuclei at near-light speeds,” says Gabriele Matzeu, a researcher at the University of Bologna, INAF associate, and the primary author of the paper documenting the results on UFOs statistics. “These findings have enhanced our understanding of these ultra-fast winds and their role in molding the evolutionary process of galaxies.”
A second paper, complementing the study, has also been published in Astronomy & Astrophysics, presenting a study of lower-velocity and lower-ionization gas flows observable in the ultraviolet band courtesy of the HST satellite.
References: “Supermassive Black Hole Winds in X-rays: SUBWAYS – I. Ultra-fast outflows in quasars beyond the local Universe” by G. A. Matzeu et al., 28 February 2023, Astronomy & Astrophysics.
DOI: 10.1051/0004-6361/202245036
“Supermassive Black Hole Winds in X-rays: SUBWAYS – II. HST UV spectroscopy of winds at intermediate redshifts” by M. Mehdipour et al., 28 February 2023, Astronomy & Astrophysics.
DOI: 10.1051/0004-6361/202245047
Table of Contents
Frequently Asked Questions (FAQs) about Ultra-Fast Outflows (UFOs)
What are UFOs mentioned in the text?
UFOs in this context refer to ultra-fast outflows, which are high-speed cosmic winds originating from the vicinity of supermassive black holes.
How do these ultra-fast outflows impact galactic evolution?
The ultra-fast outflows, or UFOs, play a significant role in shaping the evolution of galaxies. They transfer matter and energy produced by supermassive black holes to the interstellar space, affecting processes such as star formation and modifying the ecosystem of their host galaxies.
How were these UFOs detected and studied?
Researchers analyzed data obtained from ESA’s XMM-Newton space telescope and conducted observations in the X-ray and ultraviolet bands. They analyzed spectra emitted in the X-ray band, looking for absorptions caused by highly ionized materials such as iron. Additionally, they used the HST satellite to study lower-velocity and lower-ionization gas flows in the ultraviolet band.
What are active galactic nuclei (AGN)?
Active galactic nuclei are the regions surrounding supermassive black holes at the centers of galaxies. They emit enormous amounts of radiation across the entire electromagnetic spectrum when the black holes are in their active phase.
What is the SUBWAYS project?
The SUBWAYS (SUper massive Black hole Winds in the x-rAYS) project aims to investigate and understand ultra-fast outflows and their impact on the behavior of supermassive black holes in their active phase. It involves analyzing data from various telescopes, including the XMM-Newton space telescope and the HST satellite, to study active galactic nuclei and their associated phenomena.
More about Ultra-Fast Outflows (UFOs)
- SUBWAYS Project: Official Website
- ESA XMM-Newton: Mission Page
- Hubble Space Telescope (HST): Official Website
- Astronomy & Astrophysics Journal: Official Website
- University of Bologna: Official Website
5 comments
AGN, UFOs, X-rays, HST, so many acronyms! but seriously, this research is crucial to understand the dynamics of supermassive black holes. the SUBWAYS project is doing an amazing job uncovering the mysteries of these ultra-fast outflows. can’t wait for more papers!
these results confirm the existence of UFOs in galaxies! they found out that these winds can travel at speeds close to light. i’m blown away by the impact they have on star formation and the ecosystem of galaxies. space is full of surprises!
omg i never knew black holes could blow cosmic winds, that’s mindblowing! SUBWAYS project is awesome, they’re like hunting for these gas emissions and finding out how they shape galaxies. can’t wait for more discoveries!
wow, these UFOs are crazy! they are like super fast outflows from black holes and they change galaxies! amazing research project btw, i want to learn more about those supermassive black holes.
ultra-fast outflows, or UFOs as they call them, have a major impact on galactic evolution. it’s like a cosmic dance between black holes and galaxies. these scientists used cool telescopes like XMM-Newton and HST to study them. fascinating stuff!