You are browsing the site archives for May 2025.
Spectroscopic study inspects blue straggler stars in NGC 3201 Using the Magellan Clay Telescope, astronomers have performed a spectroscopic study of blue straggler stars in the globular cluster NGC 3201. Results of the new study, published May 21 on the arXiv preprint server, could help us better understand the properties and chemical composition of this cluster. phys.org Go to SourceRead More →
Space Power Satellites at the Moon Could Keep a Base Warm Lunar exploration is gaining momentum, but one of the biggest challenges remains the Moon’s long, cold night, which lasts about two weeks. To address this, a team of researchers has proposed deploying a constellation of solar power satellites in lunar orbit. These satellites would beam energy wirelessly to a base on the Moon, providing a continuous supply of 1,600 kW of power, day or night. Their proposal includes launching 300 satellites by 2035, supporting long term plans for establishing permanent lunar bases. Universe Today Go to SourceRead More →
China’s Tianwen-2 is Off to Collect an Asteroid Sample China’s Tianwen-2 mission blasted off on Wednesday, embarking on an epic 8-year journey that will help to unlock the secrets of an asteroid and a comet before delivering the precious cargo back to Earth. The spacecraft will first hunt down Kamoʻoalewa (asteroid 2016 HO3) which it will study for a year, extracting samples from its surface. After returning the sample to Earth, Tianwen-2 will head back out into the Solar System taking another 7 years to intercept the main belt comet 311P/Pan-STARRS. It will undertake a flyby study of this object that has never been studiedRead More →
Synchrotron Circular Polarization in Gamma-Ray Burst Prompt Optical Emission: Relativistic Thermal Electron Contribution Kangfa Cheng, Jirong Mao, Xiaohong Zhao, Hongbang Liu, Zhegeng Chen, Gaojin Yu, Zhifu Chen arXiv:2504.19845v2 Announce Type: replace Abstract: Synchrotron circular polarization of a non-thermal power-law electron distribution in gamma-ray bursts (GRBs) has been studied. However, some numerical simulations have shown that the resulting distribution of electrons is a combination of a thermal component and a non-thermal power-law component. In this paper, we investigate synchrotron circular polarization using such a hybrid energy distribution of relativistic thermal and nonthermal electrons within a globally toroidal magnetic field in GRB prompt optical emission. Our resultsRead More →
A Bright Future? Prospects for Cosmological Tests of GR with Multimessenger Gravitational Wave Events Elena Colangeli, Konstantin Leyde, Tessa Baker arXiv:2501.05560v2 Announce Type: replace-cross Abstract: Further bright sirens – gravitational wave events with electromagnetic counterparts – are keenly awaited, but proving elusive. The exceptional event GW170817 had a profound impact on the landscape of viable cosmological extensions of General Relativity (GR); can we expect this kind of shift to be repeated in the next decade? In this work we will assess the potential constraints from bright sirens in the LIGO-Virgo-KAGRA O5 era and third generation detector era. We set up the statistical formalism for ourRead More →
Central kiloparsec region of Andromeda. I. Dynamical modelling Lucie Cros, Franc{c}oise Combes, Anne-Laure Melchior, Thomas Martin arXiv:2411.18460v2 Announce Type: replace Abstract: The Andromeda galaxy (M31) is the most nearby giant spiral galaxy, an opportunity to study with high resolution dynamical phenomena occurring in nuclear disks and bulges, able to explain star formation quenching, and galaxy evolution through collisions and tides. Multi-wavelength data have revealed in the central kpc of M31 strong dynamical perturbations, with an off-centered tilted disk and ring, coinciding with a dearth of atomic and molecular gas. Our goal to understand the origin of these perturbations is to propose a dynamical model, reproducingRead More →
How probable is the Lyman-$alpha$ damping wing in the spectrum of the redshift z = 5.9896 quasar ULAS J0148+0600? Fiona Sawyer, James S. Bolton, George D. Becker, Luke Conaboy, Martin G. Haehnelt, Laura Keating, Girish Kulkarni, Ewald Puchwein arXiv:2502.03085v2 Announce Type: replace Abstract: The shape of the Ly-$alpha$ transmission in the near zone of the redshift $z=5.9896$ quasar ULAS J0148$+$0600 (hereafter J0148) is consistent with a damping wing arising from an extended neutral hydrogen island in the diffuse intergalactic medium (IGM). Here we use simulations of late-ending reionisation from Sherwood-Relics to assess the expected incidence of quasars with Ly-$alpha$ and Ly-$beta$ absorption similar to theRead More →
Galactic transient sources with the Cherenkov Telescope Array Observatory Cherenkov Telescope Array Observatory Consortium arXiv:2405.04469v2 Announce Type: replace Abstract: A wide variety of Galactic sources show transient emission at soft and hard X-ray energies: low- and high-mass X-ray binaries containing compact objects, isolated neutron stars exhibiting extreme variability as magnetars as well as pulsar-wind nebulae. Although most of them can show emission up to MeV and/or GeV energies, many have not yet been detected in the TeV domain by Imaging Atmospheric Cherenkov Telescopes. In this paper, we explore the feasibility of detecting new Galactic transients with the Cherenkov Telescope Array Observatory (CTAO) and the prospectsRead More →
A multi-dimensional view of a unified model for TDEs Edward J. Parkinson, Christian Knigge, Lixin Dai, Lars Lund Thomsen, James H. Matthews, Knox S. Long arXiv:2408.16371v2 Announce Type: replace Abstract: Tidal disruption events (TDEs) can generate non-spherical, relativistic and optically thick outflows. Simulations show that the radiation we observe is reprocessed by these outflows. According to a unified model suggested by these simulations, the spectral energy distributions (SEDs) of TDEs depend strongly on viewing angle: low [high] optical-to-X-ray ratios (OXRs) correspond to face-on [edge-on] orientations. Post-processing with radiative transfer codes have simulated the emergent spectra, but have so far been carried out only in aRead More →
Stealing galaxies from galaxy clusters Majda Smole, Miroslav Micic, Ana Mitrav{s}inovi’c arXiv:2505.21629v1 Announce Type: new Abstract: We investigate galaxy groups that reside in the field but have been previously processed by galaxy clusters. Observationally, they would appear to have the same properties as regular field groups at first glance. However, one would expect to find quantifiable differences in processed groups as dynamical interactions within clusters perturb them. We use IllustrisTNG300 simulation to statistically quantify that processed groups of galaxies show different properties compared to regular field groups. Our analysis encompasses a broad range of groups with total masses between $8 times 10^{11} Msun$ and $7Read More →
Gravitational wave signatures of primordial black hole accretion during early matter domination Rouzbeh Allahverdi, James B. Dent, Ngo Phuc Duc Loc, Tao Xu arXiv:2505.21885v1 Announce Type: cross Abstract: We present a scenario in which primordial black holes (PBHs) form in a post-inflationary radiation-dominated (RD) phase and then experience significant accretion during a phase of early matter dominated (EMD). We show that PBH masses could grow by up to two orders of magnitude. Restricting to the linear perturbation regime, we compute the gravitational wave (GW) spectrum that features two peaks. The high-frequency peak is associated with the PBH formation in the RD phase, while the low-frequencyRead More →
The Three Hundred Project: Modeling Baryon and Hot-Gas Fraction Evolution in Simulated Clusters Elena Rasia, Roberta Tripodi, Stefano Borgani, Veronica Biffi, Camille Avestruz, Weiguang Cui, Marco De Petris, Klaus Dolag, Dominique Eckert, Stefano Ettori, Massimo Gaspari arXiv:2505.21624v1 Announce Type: new Abstract: The baryon fraction of galaxy clusters is a powerful tool to inform on the cosmological parameters while the hot-gas fraction provides indications on the physics of the intracluster plasma and its interplay with the processes driving galaxy formation. Using cosmological hydrodynamical simulations from The Three Hundred collaboration of about 300 simulated massive galaxy clusters with median mass $M_{500}approx7 times 10^{14}$M$_{odot}$ at $z=0$, we modelRead More →
Exocomets of $beta$ Pictoris I: Exocomet destruction, sodium and disk line variability in 17 years of HARPS observations H. J. Hoeijmakers, K. P. Jaworska, B. Prinoth arXiv:2505.21625v1 Announce Type: new Abstract: The young $beta$ Pictoris system has been monitored with high-resolution optical spectrographs for decades. These observations have revealed strongly variable absorption in the Ca II H&K lines attributed to in-falling cometary bodies. Since 2003, over 9000 HARPS observations of $beta$ Pictoris have been taken and many of these have not yet been used for exocomet studies. We search these spectra for new exocomet phenomenology enabled by the long time coverage and large volume ofRead More →
DAWN JWST Archive: Morphology from profile fitting of over 340,000 galaxies in major fields Aur’elien Genin, Marko Shuntov, Gabe Brammer, Natalie Allen, Kei Ito, Georgios Magdis, Jasleen Matharu, Pascal A. Oesch, Sune Toft, Francesco Valentino arXiv:2505.21622v1 Announce Type: new Abstract: To better understand how galaxies assemble their structure and evolve over cosmic time, we present a new catalog of morphological measurements for over 340,000 sources spanning $0 3$. Quiescent galaxies also show significantly higher stellar mass surface densities, nearly an order of magnitude greater at $z sim 4$ than at $z sim 1$. Our results confirm a strong and evolving link between morphology and starRead More →
Fragmentation in Collapsar Disks: Migration, Growth, and Emission Y. Lerner, N. C. Stone, D. D. Ofengeim arXiv:2505.21617v1 Announce Type: new Abstract: We present a parameter survey of fragmentation in collapsar disks, using a revised version of the Chen & Beloborodov (2007) model that determines the structure of steady state hyperaccretion disks in a general relativistic and neutrino cooled framework. We map out the range of disk conditions leading to gravitational instability alongside an exploration of the dimensionless cooling time $beta$, which together determine whether fragmentation is likely to occur. We estimate the initial mass and density of fragments, finding that they occupy a unique regionRead More →
The ESPRESSO Redshift Drift Experiment I — High-resolution spectra of the Lyman-$alpha$ forest of QSO J052915.80-435152.0 Andrea Trost, Catarina M. J. Marques, Stefano Cristiani, Guido Cupani, Simona Di Stefano, Valentina D’Odorico, Francesco Guarneri, Carlos J. A. P. Martins, Dinko Milakovi’c, Luca Pasquini, Ricardo G’enova Santos, Paolo Molaro, Michael T. Murphy, Nelson J. Nunes, Tobias M. Schmidt, Yann Alibert, Konstantina Boutsia, Giorgio Calderone, Jonai I. Gonz’alez Hern’andez, Andrea Grazian, Gaspare Lo Curto, Enric Palle, Francesco Pepe, Matteo Porru, Nuno C. Santos, Alessandro Sozzetti, Alejandro Su’arez Mascare~no, Maria R. Zapatero Osorio arXiv:2505.21615v1 Announce Type: new Abstract: The measurement of the temporal evolution in the redshift of distantRead More →
Redshifts of Objects near 3C 220.3 S’oley ‘O. Hyman, S. P. Willner, Belinda J. Wilkes arXiv:2505.21613v1 Announce Type: new Abstract: In the course of studying the 3C 220.3 lensing system, spectra were obtained with the Binospec instrument on the MMT for 511 additional objects in 3C 220.3’s vicinity. These gave 146 good-quality galaxy redshifts and identified 126 Galactic stars. The galaxy redshift histogram shows a peak near 3C 220.3’s redshift, but there is no evidence for or against a galaxy group within 2 Mpc of 3C 220.3 itself. The spectra revealed 12 AGN candidates including a likely $zapprox4.64$ broad-line QSO. Visible and near-infrared imaging withRead More →
Quasar absorption outflows on galactic scales: Insights from DESI Maryam Dehghanian, Nahum Arav, Mayank Sharma, Gwen Walker, Kyle Johnston, Matthew Kaupin, Justin Gandhi arXiv:2505.21630v1 Announce Type: new Abstract: Absorption outflows in quasars play an important role in understanding active galactic nuclei (AGN) feedback and their influence on galaxy evolution. The unprecedented spectral data provided by the Dark Energy Spectroscopic Instrument (DESI) opens new avenues to explore these outflows. We analyze five low-ionization absorption outflow systems in four intermediate-redshift quasars (2 arXiv:2505.21630v1 Announce Type: new Abstract: Absorption outflows in quasars play an important role in understanding active galactic nuclei (AGN) feedback and their influence on galaxyRead More →
Bursty or heavy? The surprise of bright Population III systems in the Reionization era Alessandra Venditti, Julian B. Munoz, Volker Bromm, Seiji Fujimoto, Steven L. Finkelstein, John Chisholm arXiv:2505.20263v1 Announce Type: cross Abstract: The nature of the first, so-called Population III (Pop III), stars has for long remained largely unconstrained. However, the James Webb Space Telescope (JWST) finally opened new concrete prospects for their detection during the Epoch of Reionization (EoR), notably providing promising observational constraints on the Pop III ultra-violet luminosity function (UVLF) at $z sim 6.5$. These preliminary data hint towards an unexpected population of UV-bright Pop III sources, which challenges the prevailingRead More →
Detection of the Geminga pulsar at energies down to 20 GeV with the LST-1 of CTAO The CTAO-LST Project, :, K. Abe, S. Abe, A. Abhishek, F. Acero, A. Aguasca-Cabot, I. Agudo, C. Alispach, D. Ambrosino, F. Ambrosino, L. A. Antonelli, C. Aramo, A. Arbet-Engels, C. Arcaro, T. T. H. Arnesen, K. Asano, P. Aubert, A. Baktash, M. Balbo, A. Bamba, A. Baquero Larriva, U. Barres de Almeida, J. A. Barrio, L. Barrios Jim’enez, I. Batkovic, J. Baxter, J. Becerra Gonz’alez, E. Bernardini, J. Bernete, A. Berti, I. Bezshyiko, C. Bigongiari, E. Bissaldi, O. Blanch, G. Bonnoli, P. Bordas, G. Borkowski, G. Brunelli, A. Bulgarelli,Read More →
