The strong electromagnetic environment near a black hole can accelerate particles to a large fraction of the speed of light, sending them along jets extending from each pole of the object. In the case of supermassive black holes found at the centers of galaxies, these jets are truly massive, with material exploding not only from outside the galaxy, but perhaps from the galaxy’s entire neighborhood.
But this week, scientists explained how jets are also doing strange things inside galaxies. A study of galaxy M87 showed that nova explosions appear to occur at an unusually high frequency near one of the jets from the galaxy’s central black hole. However, there is no mechanism at all to explain why this happens, and there is no indication that it is happening with jets flying in the opposite direction.
Further observations may be needed to see if this effect is real and if we can come up with an explanation for it.
Novus and Wedge
M87 is one of them. bigger galaxy Located in a localized part of the universe, the central black hole has active jets. During early routine observations, the Hubble Space Telescope discovered that stellar explosions called novae appeared to cluster around jets.
This makes little sense. Novaes occur in systems with large hydrogen-rich stars and nearby orbiting white dwarfs. Over time, the white dwarf pulls hydrogen from the surface of its companion star until it reaches a critical surface mass. At that point, a thermonuclear explosion blows the remaining material out of the white dwarf and the cycle is reset. The rate of mass transfer tends to be fairly stable, so novae within a star system often repeat at regular intervals. And it’s not at all clear why a black hole’s jet changes its regularity.
So some of the people involved in the original study took time to return to Hubble and take another look. Then, every five days for the better part of a year, Hubble was able to point toward M87 and catch the nova before it disappeared. Overall, it detected 94 novae that originated near the center of the galaxy. Combined with the 41 identified in previous research, this left a collection of 135 novae in the galaxy. The researchers then plotted these compared to a black hole and its jets.
The region containing the jet (top right) produces far more novae than the rest of the galaxy’s center.
Lessing et al. Al.
The researchers divided the region near the center of the galaxy into 10 equal parts and counted the number of novae that formed in each region. In the nine jet-free segments on the galactic side facing Earth, the average number of novae was 12. In the segment that included jets, that number was 25. Another way to look at this is that the maximum number of non-jet segments was only 16, and that was the segment right next to the segment containing jets. The researchers calculate that the chance of this arrangement occurring randomly is about 1 in 1,310, or less than 0.1 percent.
To get another measure of how unusual this is, the researchers placed 8 million novae around the galaxy’s center. Although the distribution is random, it is biased to match the brightness of galaxies, under the assumption that novae occur more frequently in star-rich regions. . We then used this to estimate how often novae could be expected in each of these segments. Next, they used different wedges. “We averaged the results for wedges between 30 and 45 degrees wide to reduce noise and avoid hacking when selecting wedge sizes.”
Overall, as you might expect, reinforcement near the jet was low for both very narrow and very wide wedges. A narrow wedge cuts out more of the area affected by the jet, while a wider wedge contains more space for the normal effect. background rate. The peak occurs in the region of a 25 degree wide wedge, and the enrichment near the jet is approximately 2.6 times. So this seems real.
