Credit: X-ray: NASA/CXC/Princeton Univ/C. Bambic et al.;
Optical: SDSS; Radio: NSF/NRAO/VLA/ESO;
Image processing: NASA/CXC/SAO/N.Wolk
This “H”-shaped structure is found in a detailed new X-ray map of the multimillion-degree gas around the galaxy Messier 84 (M84).
As gas is captured by the gravitational force of the black hole, some of it will fall into the abyss, never to be seen again. Some of the gas, however, avoids this fate and instead gets blasted away from the black hole in the form of jets of particles. These jets can push out cavities, in the hot gas surrounding the black hole. Given the orientation of the jets to Earth and the profile of the hot gas, the cavities in M84 form what appears to resemble the letter “H.” The H-shaped structure in the gas is an example of pareidolia, which is when people see familiar shapes or patterns in random data. Pareidolia can occur in all kinds of data from clouds to rocks and astronomical images.
Credit: X-ray: NASA/CXC/Princeton Univ/C. Bambic et al.;
Optical: SDSS; Radio: NSF/NRAO/VLA/ESO;
Image processing: NASA/CXC/SAO/N.Wolk
Credit: X-ray: NASA/CXC/Princeton Univ/C. Bambic et al.;
Optical: SDSS; Radio: NSF/NRAO/VLA/ESO;
Image processing: NASA/CXC/SAO/N.Wolk
The authors tested a model called Bondi accretion, where all of the matter within a certain distance from a black hole — effectively inside a sphere — is close enough to be affected by a black hole’s gravity and start falling inwards at the same rate from all directions. (The dashed circle in the close-up image is centered on the black hole and shows the approximate distance from the black hole where gas should start falling inwards.) This effect is named after the scientist Hermann Bondi, and “accretion” refers to matter falling toward the black hole. The new results show that Bondi accretion is not occurring in M84 because matter is not falling towards the black hole evenly from all directions.
M84 is a cousin of Messier 87 (M87), the galaxy containing the first
black hole imaged with the global Event Horizon Telescope network, and,
like M87, is also a member of the Virgo Cluster. The supermassive black
hole in M84, along with those in our galaxy, M87, NGC 3115, and NGC
1600, are the only ones close enough to Earth, or massive enough, for
astronomers to see details in Chandra images which are so near the black
hole that gas should be falling inwards. Like the black hole in M87,
the one in M84 is producing a jet of particles; however, the point
source of X-rays from material even closer to the black hole is over ten
times fainter for M84. This allows more detailed study of gas falling
towards the black hole in M84 that is farther out, preventing the faint
X-rays produced by this gas from being overwhelmed by the X-ray glare
from the point source.
A paper describing these results appears in The Monthly Notices of the Royal Astronomical Society and a preprint is available here.
The study was led by Christopher Bambic, a graduate student at
Princeton University. Other authors include Helen Russell (University of
Nottingham, United Kingdom), Christopher Reynolds (Institute of
Astronomy, Cambridge, UK; University of Maryland, College Park), Andy
Fabian (Institute of Astronomy), Brian McNamara (University of Waterloo,
Canada; Waterloo Centre for Astrophysics, Canada), and Paul Nulsen
(Center for Astrophysics | Harvard & Smithsonian).
Fast Facts for M84:
Scale: Image is about 9 arcmin (140,000 light-years) across.
Category: Normal Galaxies & Starburst Galaxies, Black Holes
Coordinates (J2000): RA 12h 25m 03.74s | Dec +12° 53´ 13.14"
Constellation: Virgo
Observation Dates: 26 observations from May 2000 through May 2019
Observation Time: 234 hours 39 minutes (9 days 18 hours 39 minutes)
Also Known As: NGC 4374
References: Bambic, C. et al. 2023, MNRAS,(accepted); arXiv:2301.11937
Color Code: X-ray: pink; Optical: red, green, blue; Radio: blue;
Distance Estimate: About 55 million light-years
