An artist's illustration of a supermassive black hole (SMBH.) The JWST has revealed SMBHs in the early Universe that are much more massive than our scientific models can explain. Could primordial black holes have acted as "seeds" for these massive SMBHs? Image Credit: ESA
Not long ago, the James Webb Space Telescope (JWST) peered into Cosmic Dawn, the cosmological period when the first galaxies formed less than one billion years after the Big Bang. In the process, it discovered something rather surprising. Not only were there more galaxies (and brighter ones, too!) than expected, but these galaxies had supermassive black holes (SMBH) much larger than cosmological models predicted. For astronomers and cosmologists, explaining how these galaxies and their SMBHs (aka. quasars) could have grown so large less than a billion years after the Big Bang has become a major challenge.
Several proposals have been made, ranging from optical illusions to Dark Matter accelerating black hole growth. In a recent study, an international team led by researchers from the National Institute for Astrophysics (INAF) analyzed a sample of 21 quasars, among the most distant ever discovered. The results suggest that the supermassive black holes at the center of these galaxies may have reached their surprising masses through very rapid accretion, providing a plausible explanation for how galaxies and their SMBHs grew and evolved during the early Universe.
This collection of images was released to commemorate the 25th anniversary of Chandra. Image credit: NASA / CXC / SAO.
It’s not always possible to observe the night sky from the surface of the Earth. The blocking effects of the atmosphere mean we sometimes need to put telescopes out into space. The Chandra X-Ray Observatory is one such telescopes and it has just completed its 25th year of observations. To celebrate, NASA have just released 25 never-before-seen images of various celestial objects in x-rays. The collection includes images showing the region around black holes, giant clouds of hot gas and extreme magnetic fields. Sadly though, NASA is planning on shutting down the mission to save budget so best to enjoy the images while you can.
The US Government budget announcement in March left NASA with two billion dollars less than it asked for. The weeks that followed have left NASA with some difficult decisions forcing cuts across the agency. There will be a number of cuts across the agency but one recent decision came as quite a shock to the scientific community. NASA have just announced they are no longer going to support the Chandra X-Ray Observatory which has been operational since 1999 and made countless discoveries.
Artist impression of an X-ray binary system. This one is called MAXI J1820+070 containing a black hole (small black dot at the center of the gaseous disk) and a companion star. A narrow jet is directed along the black hole spin axis, which is strongly misaligned from the rotation axis of the orbit. Image produced with Binsim (credit: R. Hynes).
The planets in our Solar System all rotate on axes that roughly match the Sun’s rotational axis. This agreement between the axes of rotation is the typical arrangement in any system in space where smaller objects orbit a larger one.
But in one distant binary system, the large central object has an axis of rotation tilted about 40 degrees compared to its smaller satellite. This situation is even more strange because the main body isn’t a star but a black hole.
Hundreds of millions of light years away, a supermassive black hole sits in the center of a galaxy cluster named Ophiuchus. Though black holes are renowned for sucking in surrounding material, they sometimes expel material in jets. This black hole is the site of an almost unimaginably powerful explosion, created when an enormous amount of material was expelled.
That's the case with NGC 2207 and IC 2163, which are located about 130 million light-years from Earth, in the constellation of Canis Major. Image credit: NASA/CXC/SAO/STScI/JPL-Caltech
At this time of year, festive displays of light are to be expected. This tradition has clearly not been lost on the galaxies NHC 2207 and IC 2163. Just in time for the holidays, these colliding galaxies, which are located within the Canis Major constellation (some 130 million light-years from Earth,) were seen putting on a spectacular lights display for us folks here on Earth!
And while this galaxy has been known to produce a lot of intense light over the years, the image above is especially luminous. A composite using data from the Chandra Observatory and the Hubble and Spitzer Space Telescopes, it shows the combination of visible, x-ray, and infrared light coming from the galactic pair.
In the past fifteen years, NGC 2207 and IC 2163 have hosted three supernova explosions and produced one of the largest collections of super bright X-ray lights in the known universe. These special objects – known as “ultraluminous X-ray sources” (ULXs) – have been found using data from NASA’s Chandra X-ray Observatory.
While the true nature of ULXs is still being debated, it is believed that they are a peculiar type of star X-ray binary. These consist of a star in a tight orbit around either a neutron star or a black hole. The strong gravity of the neutron star or black hole pulls matter from the companion star, and as this matter falls toward the neutron star or black hole, it is heated to millions of degrees and generates X-rays.
The core of galaxy Messier 82 (M82), where two ultraluminous X-ray sources, or ULXs, reside (X-1 and X-2). Credit: NASA
Data obtained from Chandra has determined that – much like the Milky Way Galaxy – NGC 2207 and IC 2163 are sprinkled with many star X-ray binaries. In the new Chandra image, this x-ray data is shown in pink, which shows the sheer prevalence of x-ray sources within both galaxies.
Meanwhile, optical light data from the Hubble Space Telescope is rendered in red, green, and blue (also appearing as blue, white, orange, and brown due to color combinations,) and infrared data from the Spitzer Space Telescope is shown in red.
The Chandra observatory spent far more time observing these galaxies than any previous ULX study, roughly five times as much. As a result, the study team – which consisted of researchers from Harvard University, MIT, and Sam Houston State University – were able to confirm the existence of 28 ULXs between NGC 2207 and IC 2163, seven of which had never before been seen.
In addition, the Chandra data allowed the team of scientists to observe the correlation between X-ray sources in different regions of the galaxy and the rate at which stars are forming in those same regions.
The Mice galaxies, seen here well into the process of merging. Credit: Hubble Space Telescope
As the new Chandra image shows, the spiral arms of the galaxies – where large amounts of star formation is known to be occurring – show the heaviest concentrations of ULXs, optical light, and infrared. This correlation also suggests that the companion star in the star X-ray binaries is young and massive.
This in turn presents another possibility which has to do with star formation during galactic mergers. When galaxies come together, they produce shock waves that cause clouds of gas within them to collapse, leading to periods of intense star formation and the creation of star clusters.
The fact that the ULXs and the companion stars are young (the researchers estimate that they are only 10 million years old) would seem to confirm that they are the result of NGC 2207 and IC 2163 coming together. This seem a likely explanation since the merger between these two galaxies is still in its infancy, which is attested to by the fact that the galaxies are still separate.
They are expected to collide soon, a process which will make them look more like the Mice Galaxies (pictured above). In about one billion years time, they are expected to finish the process, forming a spiral galaxy that would no doubt resemble our own.
