NASA’s Chandra Unveils Mysterious X-Ray Objects

X-ray: NASA/CXC/Univ. of Alabama/M. Muhibullah et al.; Optical: NASA/ESA/STScI; Image Processing: NASA/CXC/SAO/N. Wolk

Using NASA’s Chandra X-ray Observatory, scientists have discovered a new class of objects behaving unlike any they have seen before. Astronomers suggest these newly spotted objects in other galaxies may help solve not one, but two long-standing questions in astrophysics.

These mysterious objects give off unusually low-energy X-rays but intense levels of ultraviolet radiation. This discovery is featured in a paper published Wednesday in Nature Astronomy.

“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.” 

M101 with illustrated circles calling out seven of the newly-discovered objects.

X-ray: NASA/CXC/Univ. of Alabama/M. Muhibullah et al.; Optical: NASA/ESA/STScI; Image Processing: NASA/CXC/SAO/N. Wolk 

The researchers found a total of 84 of these “hypersoft X-ray sources” – so named because they give such low-energy X-rays – in the six different galaxies they searched, using data openly available to the public in the Chandra archive. Two of the galaxies are spirals, M31 (the Andromeda galaxy) and M101 (the Pinwheel galaxy), while the other four are ellipticals. They found hypersoft X-ray sources both in regions of active star formation and areas where there are older stars.

The 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. That means these objects give off far more low-energy X-rays than high-energy ones. Because low-energy X-rays border energetic ultraviolet radiation on the electromagnetic spectrum, the researchers determined that these sources are producing large amounts of energetic ultraviolet radiation as well.

It is unclear what types of objects are responsible for these low-energy X-rays and intense ultraviolet radiation. The team thinks they 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. Such binary systems have been seen before, but not with such bright ultraviolet radiation and low-energy X-rays.

The discovery suggests that there may be large populations of binary systems with energetic ultraviolet radiation that have been undetected until now.

“These clandestine X-ray sources are actually among the most energetic objects in galaxies, and they could be solving two cosmic mysteries at once,” said Muhibullah.

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. 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.”

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. The intense levels of ultraviolet radiation from the hypersoft X-ray sources may play a vital role.

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.

“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.”

NASA's Marshall Space Flight Center in Huntsville, Alabama, manages the Chandra program. The Smithsonian Astrophysical Observatory's Chandra X-ray Center controls science operations from Cambridge, Massachusetts, and flight operations from Burlington, Massachusetts.

Read more from NASA’s Chandra X-ray Observatory

To learn more about NASA’s Chandra mission, visit: https://www.nasa.gov/chandra 

Source: NASA’s Chandra Unveils Mysterious X-Ray Objects - NASA Science

Cord Blood Could Turn Into an Off-the-Shelf Cancer Weapon, UCLA Study Suggests

Personalized cell therapies have transformed cancer treatment for some patients, but they share a common problem: each dose has to be custom-built from that patient’s own cells, a process that can take weeks and cost hundreds of thousands of dollars. A team at UCLA thinks they’ve found a way around that bottleneck, by starting not with mature immune cells, but with stem cells taken from donated cord blood.

Going a Step Deeper Than CAR-T

The therapy relies on T cell receptor (TCR) engineering, a cousin of the better-known CAR-T approach. CAR-T cells can only recognize proteins sitting on the outer surface of a cancer cell. TCR-based cells go further: they can spot fragments of proteins made inside a tumor cell and later displayed on its surface like an identifying tag. That distinction matters a lot for solid tumors, where many of the telltale molecular changes never make it to the cell’s exterior.

The catch has always been manufacturing. Personalized TCR therapy requires processing each patient’s own cells individually. Ready-made versions built from donor T cells exist too, but they carry a serious risk: graft-versus-host disease, in which the transplanted immune cells attack the recipient’s healthy tissue.

Starting Earlier in the Cell’s Life

Instead of engineering mature donor T cells, the UCLA team, led by Lili Yang, with co-first author Yichen (John) Zhu and co-senior author Yanruide (Charlie) Li, started with blood stem cells pulled from cord blood. These cells haven’t yet committed to becoming any particular immune cell type. The researchers inserted a gene for a receptor that recognizes NY-ESO-1, a protein found across many solid tumor types, and then let the engineered stem cells mature into T cells in the lab.

Because the receptor is added before the cells differentiate, the resulting T cells don’t carry the random grab-bag of natural receptors that mature donor T cells do, which is exactly what causes graft-versus-host disease in the first place. Every resulting cell, called an AlloESO-T cell, homes in on the same target.

A Second Way to Catch Cancer

Solid tumors are notoriously good at slipping past single-target therapies, some cancer cells simply stop displaying the marker a treatment is designed to find, a phenomenon called antigen escape. To hedge against that, the AlloESO-T cells were also built to carry natural killer cell receptors that respond to general stress signals many tumor cells give off, giving the cells a backup way to identify and kill cancer even if it stops presenting NY-ESO-1.

What Happened in Mice

In mouse models of ovarian cancer and melanoma, a single dose of AlloESO-T cells produced durable tumor control and longer survival — while cells engineered from conventional mature donor T cells only partially controlled tumors and triggered graft-versus-host disease. After infusion, the AlloESO-T cells expanded roughly 100-fold, migrated into tumors, and stayed active for weeks while largely sparing healthy organs, a marked contrast to the donor-derived cells, which built up in the liver and lungs and caused toxicity.

Why Scale Matters

Because stem cells can be expanded so extensively, the manufacturing math changes dramatically. The team estimates that a small starting batch of cord blood stem cells could be turned into trillions of therapeutic cells, enough for thousands of doses, in about six weeks, at a projected cost of roughly $5,000 per dose. That’s a steep drop from the six-figure price tags attached to today’s personalized cell therapies.

The researchers also frame AlloESO-T as a platform rather than a one-off product: any validated receptor for a given cancer antigen could, in principle, be built into the same stem-cell-based system to generate T cells against a different target. UCLA has already partnered with its Center for Advanced Biotherapies to manufacture clinical-grade cells for a related program, and hopes to lean on that same infrastructure to move AlloESO-T toward clinical testing.

It’s worth underlining that these results are preclinical, the therapy has only been tested in mice so far, not in human trials, and hasn’t been evaluated by the FDA. But as a proof of concept for cheaper, faster, off-the-shelf cell therapy against solid tumors, it’s a compelling one. The study was published in Cell Reports Medicine.

Sources

·         UCLA Health press release: Scientists engineer ready-to-use cancer-fighting T cells for solid tumors

·         Original paper: Zhu et al., “Scalable generation of hematopoietic stem cell-engineered off-the-shelf mono-specific cytotoxic T cells targeting solid tumors,” Cell Reports Medicine, 2026

Source: Cord Blood Could Turn Into an Off-the-Shelf Cancer Weapon, UCLA Study Suggests