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Dec 9, 2024 | 
eurekalert.org | Astroparticle Physics
In short: “We exist, therefore the universe is made to host us”: the anthropic principle has sparked intense debate in cosmology since its first formulation. A new paper published in JCAP proposes a way to test it.
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Oct 4, 2024 | 
eurekalert.org | Astroparticle Physics
One of the great challenges of modern cosmology is to reveal the nature of dark matter. We know it exists (it constitutes over 85% of the matter in the Universe), but we have never seen it directly and still do not know what it is. A new study published in JCAP has examined traces of antimatter in the cosmos that could reveal a new class of never-before-observed particles, called WIMP (Weakly Interacting Massive Particles), which could make up dark matter.
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Aug 28, 2024 | 
link.aps.org | Astroparticle Physics |Kimberly K. Boddy |Tristan Smith |Jonathan Nay
We investigate the use of harmonic analysis techniques to perform measurements of the angular power spectrum on mock pulsar timing data for an isotropic stochastic gravitational-wave background (SGWB) with a dimensionless strain amplitude Agw=2×10−15 and spectral index γgw=13/3. We examine the sensitivity of our harmonic analysis to the number of pulsars (50, 100, and 150) and length of pulsar observation time (10, 20, and 30 years) for an isotropic distribution of pulsars.
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Jul 4, 2024 | 
academic.oup.com | Instituto de Astronomia |Optica y Electronica |Astroparticle Physics
In this work, we present the results of a detailed X-ray spectral analysis of the brightest AGNs detected in the XMM-Newton 1.75 Ms Ultra Narrow Deep Field. We analyzed 23 AGNs that have a luminosity range of in the energy band, redshifts up to 2.66, and ∼10, 000 X-ray photon counts in the energy band.
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May 1, 2024 | 
eurekalert.org | Astroparticle Physics
A group of researchers at the University of Waterloo and the University of British Columbia have discovered a potential “cosmic glitch” in the universe’s gravity, explaining its strange behaviour on a cosmic scale. For the last 100 years, physicists have relied upon Albert Einstein’s theory of “general relativity” to explain how gravity works throughout the universe.
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Apr 19, 2024 | 
eurekalert.org | Astroparticle Physics
Thanks to the dizzying growth of cosmic observations and measurement tools and some new advancements (primarily the “discovery” of what we call dark matter and dark energy) all against the backdrop of General Relativity, the early 2000s were a time when nothing seemed capable of challenging the advancement of our knowledge about the cosmos, its origins, and its future evolution.
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Mar 28, 2024 | 
academic.oup.com | Astroparticle Physics |Argelander-Institut für Astronomie |Universität Bonn
We present observations of the central 9 kpc of the Antennae merger (NGC 4038/9) at 55 pc resolution in the CO (2–1) line obtained with the Atacama Large Millimeter/submillimeter Array (ALMA). We use a pixel-based analysis to compare the gas properties in the Antennae to those in 70 nearby spiral galaxies from the PHANGS-ALMA survey, as well as the merger and nearest luminous infrared galaxy NGC 3256.
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Nov 20, 2023 | 
academic.oup.com | Astroparticle Physics
We examine the properties of ∼50, 000 rotational variables from the ASAS-SN survey using distances, stellar properties, and probes of binarity from Gaia DR3 and the SDSS APOGEE survey. They have higher amplitudes and span a broader period range than previously studied Kepler rotators. We find they divide into three groups of main sequence stars (MS1, MS2s, MS2b) and four of giants (G1/3, G2, G4s, and G4b).
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May 27, 2023 | 
academic.oup.com | Astroparticle Physics
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Apr 11, 2023 | 
link.aps.org | Astroparticle Physics
Abstract We propose a novel and simple scenario to explain baryon asymmetry and dark matter (DM) by utilizing an early matter-dominated era (EMDE) caused by a heavy metastable particle. Within the EMDE, lack of pressure enhances the formation of primordial black holes (PBHs) which can then contribute to the relic abundance of DM. The eventual decay of heavy metastable particle that has baryon number and CP-violating interactions reheats the Universe and gives rise to baryon asymmetry.
