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Credit: David Champion/MPIfR.
Dark matter is composed of particles that do not reflect, emit, or absorb light, and is predicted to make up the majority of matter in the universe. However, due to the lack of interaction with light, it cannot be directly detected using traditional experimental methods.
Physicists have been trying to devise alternative ways to detect and study dark matter for decades, but many questions about its nature and its presence in our galaxy remain unanswered. The Pulsar Timing Array (PTA) experiment searches for the presence of so-called ultralight dark matter particles by studying the timing of the assembly of galactic millisecond radio pulsars (that is, objects that emit regular, millisecond-long radio pulses). I’m about to try.
The European Pulsar Timing Array, a multinational team of researchers based in various institutions that uses six radio telescopes across Europe to observe specific pulsars, recently I analyzed the waves. their paperswas announced in physical review lettersets tighter constraints on the existence of ultralight dark matter within the Milky Way.
“This paper is basically the result of my first PhD project,” Clemente Smara, a co-author of the paper, told Phys.org. “The idea arose when I asked my supervisor if we could carry out research focused on gravitational wave science from a particle physics perspective.The main purpose of this project was to The aim was to suppress the presence of so-called ultralight dark matter in galaxies.”
Ultralight dark matter is a hypothetical dark matter candidate composed of very light particles that could potentially address long-standing mysteries in the field of astrophysics. A recent study by Smara and colleagues aimed to explore the possibility of this type of dark matter existing in our galaxy through data collected by the European Pulsar Timing Array.
“We look forward to our previous efforts in this area, especially The work of Polaiko and his collaborators“Thanks to the longer duration and improved accuracy of our dataset, we are now able to place tighter constraints on the presence of ultralight dark matter in the Milky Way,” Smara said.
A recent paper by the European Pulsar Timing Array makes different assumptions than those made in other studies conducted in the past. Instead of investigating the interactions between dark matter and ordinary matter, we assume that these interactions occur only due to the effects of gravity.
“We hypothesized that dark matter interacts with ordinary matter only through gravitational interactions,” Smara explained. “This is a pretty solid claim. In fact, the only thing we know for sure about dark matter is that it interacts gravitally. In short, dark matter is a pulsar radio beam generates potential wells for passage through. However, the depth of these wells is periodic in time, so the travel time of the radio beam from the pulsar to Earth also varies with a unique periodicity. .”
By looking for this particular effect in the second wave of data released by the European Pulsar Timing Array, Smara and his colleagues were able to set new constraints on the existence of ultralight dark matter around pulsars. The European Pulsar Timing Array has been collecting this data for almost 25 years using his six high-performance radio telescopes located across Europe.
“Based on our analysis, we can rule out the possibility that ultralight particles in a certain mass range make up the entire amount of dark matter,” Smara said. “So even if they were there, we would need something else to explain what we are seeing. And the only thing we know for sure is This result is quite robust because we focused on the gravitational interaction of dark matter.”
A recent study by the European Pulsar Timing Array found that ultralight particles with masses 10−24.0 eV≲m≲10−23.3 eV cannot constitute 100% of the measured local dark matter density, and at most ρ≲0.3 This shows that it is possible to have a local density of . GeV/cm3. These new constraints may guide further research in this field and may inform future searches for this elusive dark matter candidate.
“I now plan to investigate whether there are signatures in pulsars that can tell us anything more about dark matter,” Smara added. “Furthermore, I am interested in PTA science in general, and therefore the astrophysics of supermassive black hole binary systems, which are thought to be a plausible explanation for the stochastic gravitational wave background that we have recently observed. I also want to try modeling.”
For more information:
Clemente Smarra et al., Second Data Release from the European Pulsar Timing Array: Challenging the Ultralight Dark Matter Paradigm, physical review letter (2023). DOI: 10.1103/PhysRevLett.131.171001
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