NASA Chandra Observatory Discovers 84 Mysterious Cosmic Objects Across Galaxies

Chandra X-ray Observatory Data and M31 and M101 Galaxies

Using data openly available to the public in the Chandra archive, researchers identified 84 objects dubbed hypersoft X-ray sources across six different galaxies, as reported by NASA’s Chandra X-ray Observatory. The discovery encompasses two spiral galaxies—M31 (the Andromeda galaxy) and M101 (the Pinwheel galaxy)—alongside four elliptical galaxies. They found hypersoft X-ray sources both in regions of active star formation and areas where there are older stars.

Detecting Hypersoft X-Ray Sources in M31 and M101

The research team spotted the sources by finding objects that appeared in Chandra images taken at the lowest X-ray energies but vanished in higher-energy images. Because low-energy X-rays border energetic ultraviolet radiation on the electromagnetic spectrum, scientists deduced that these sources are producing large amounts of energetic ultraviolet radiation as well. Why were these hypersoft X-ray sources not found until now? In addition to the low-energy X-ray output, which is very difficult for X-ray telescopes to detect, the high-energy ultraviolet radiation is readily absorbed by helium and hydrogen gas that fills the space between the stars, creating a nearly impenetrable barrier to look through.

Rosanne Di Stefano and Mustafa Muhibullah on Hypersoft X-Ray Sources

By combing through the Chandra archive, we were able to eliminate what used to be a blind spot for telescopes, said co-author Rosanne Di Stefano of the Center for Astrophysics | Harvard & Smithsonian. That’s how we found what appears to be a new class of cosmic objects with remarkable qualities.

Mustafa Muhibullah, University of Alabama study leader

We’ve never encountered a group of objects that act like this, said Mustafa Muhibullah of the University of Alabama who led the study. Of course, the next step was to try to figure out what these things are. Muhibullah also noted: These clandestine X-ray sources are actually among the most energetic objects in galaxies, and they could be solving two cosmic mysteries at once. Astronomers think that the objects most likely involve a black hole, neutron star, or white dwarf pulling material from a companion star. The material pulled from the companion star is heated up to produce X-rays before falling onto the white dwarf or neutron star, or into the black hole. While such binary systems have been seen before, they have not been seen with such bright ultraviolet radiation and low-energy X-rays, suggesting that there may be large populations of binary systems with energetic ultraviolet radiation that have been undetected until now.

New Supernova Dataset Challenges Dark Energy Theory

Solving Cosmic Mysteries: Supernovae and Gas Ionization

Jimmy Irwin and University of Alabama Researchers

Astrophysicists suggest that these newly found hypersoft sources could simultaneously resolve two major puzzles in the field. Scientists think that some white dwarf systems pulling material from companion stars may eventually explode as a supernova—known as a Type Ia—that is critical for measuring the expansion of the universe. These supernovae played a key role in discovering that this expansion is accelerating, and astronomers have been looking for the stars that turn into Type Ia supernovae for many years, so far without success.

If we could find a way to spot these Type Ia supernova explosions before they go off, that would be really important, said co-author Jimmy Irwin, also of the University of Alabama. Right now, we study them after they’ve exploded, and astronomers have struggled to understand what is actually ignited.

Beyond stellar explosions, the other mystery these hypersoft X-ray sources might explain is what strips electrons from gas between the stars in some galaxies. This stripping of electrons is important to probe because it can affect how quickly stars form and influence the life cycles of galaxies. Hot, massive stars play a role, but they do not completely explain what is causing this stripping, meaning the intense levels of ultraviolet radiation from the hypersoft X-ray sources may play a vital role. Researchers said further observations are now planned to pinpoint the nature of the objects and test their role in shaping galaxies.