Universe TodaySpace and astronomy news

Researchers have used the Chandra X-Ray Observatory to understand just how large supermassive black holes can get by performing a very detailed census of the mysterious objects. These are the gigantic black holes, with millions of times the mass of our Sun, that sit at the centre of almost every galaxy. The largest of them reach 100 million solar masses and gained this weight early – then they ran out of material to consume. The smaller holes, between 10 and 100 million solar masses, have been more frugal with the gas and dust they consume, and continue to grow to this day.

NASA’s Swift space observatory has seen its first Gamma-Ray Burst (GRB), probably the birth of a black hole. Swift detected the explosion on January 17, and turned to face it within 200 seconds – enough time to watch the explosion with its X-Ray telescope. This is the first time an X-Ray observatory has ever watched a GRB while it was bursting, and not just the afterglow. Swift is still in its checkout phase, so its Ultraviolet/Optical telescope wasn’t ready to image the GRB yet, but it should be ready by February 1.

Astronomers now believe that all large galaxies have a supermassive black hole at their centre, but it was believed that these black holes formed after the galaxy. The evidence is starting to point the other way, that these black holes formed soon after the Big Bang, and then the galaxies built up around them. New observations from the Chandra X-Ray Observatory show a distant quasar that formed less than a billion years after the Big Bang, and was already producing the same amount of energy as twenty trillion Suns.

A French/US team of astronomers have discovered a second black hole is lurking at the heart of our Milky Way galaxy, completely separate from the supermassive black hole that we’ve known about for years. This new object, IRS 13E, contains only 1,400 stellar masses, which is much less that the 4 million stellar masses of our supermassive black hole. IRS 13E probably used to be located far away from the galactic centre, where a cluster of stars could safely form. All that’s left now are a few massive stars whipping around the black hole as it spirals towards the centre of our galaxy.

Astronomers from the Harvard-Smithsonian Center for Astrophysics have found what they believe is an intermediate sized black hole at the heart of a nebula in a nearby galaxy. Since black holes themselves are invisible, they located it because a spot inside the nebula is emitting a tremendous amount of X-rays, and illuminating a 100 light-year swath. By calculating the amount of X-rays pouring out, astronomers estimate that the black hole has about 25-40 solar masses. It’s unknown how these intermediate-sized black holes form, since so few of them have ever been seen.

A team of European astronomers has used a virtual observatory to find 30 previously undiscovered black holes. The team combined images from several observatories (Hubble, Chandra, ESO) in many wavelengths of light (from infrared to X-ray) into a comprehensive computer catalog of the night sky. They uncovered these new black holes by looking at galaxies which are edge on, so the supermassive black holes at their centre are obscured by a cloud of gas and dust. By comparing between the different wavelengths of light, they were able to spot the new black holes.

Researchers from Penn State University have developed a computer model that describes the interaction of a binary black hole system; where two black holes orbit one another. Previous models have fallen apart because the gravity of the black holes distorts the surrounding space so dramatically, it’s almost impossible to calculate. This unusual situation could generate gravity waves detectable from Earth, which so far have only been theorized by mathematicians.

Astronomers from several US universities have developed a scenario where colliding black holes could be ejected from their galaxy. When two galaxies merge, their central supermassive black holes will orbit one another and eventually collide. When this merge happens, the radiation pressure is so large that it could theoretically knock the black hole out of the centre of the galaxy. Although it should be incredibly rare, it could be possible to spot a black hole in a recently merged galaxy which isn’t at the centre where it normally belongs.

Image credit: ESO A team of astronomers have spotted an otherwise normal star make a close pass with the supermassive black hole that lurks at the centre of our Milky Way Galaxy. At its closest approach, the star was only 17 light-hours away from the black hole (three times the distance of the Sun to […]