RAS_WEB (Page 26)

LAMOST J1010+2358 is not a Pair-Instability Supernova Relic Pierre N. Thibodeaux, Alexander P. Ji, William Cerny, Evan N. Kirby, Joshua D. Simon arXiv:2404.17078v1 Announce Type: new Abstract: The discovery of a star formed out of pair-instability supernova ejecta would have massive implications for the Population III star initial mass function and the existence of stars over 100 Msun, but none have yet been found. Recently, the star LAMOST J1010+2358 was claimed to be a star that formed out of gas enriched by a pair-instability supernova. We present a non-LTE abundance analysis of a new high-resolution Keck/HIRES spectrum of J1010+2358. We determined the carbon and aluminumRead More →

Hybrid Radiation Hydrodynamics scheme with gravity tree-based adaptive optimization algorithm Cheryl S. C. Lau, Maya A. Petkova, Ian A. Bonnell arXiv:2404.17084v1 Announce Type: new Abstract: Modelling the interaction between ionizing photons emitted from massive stars and their environment is essential to further our understanding of galactic ecosystems. We present a hybrid Radiation-Hydrodynamics (RHD) scheme that couples an SPH code to a grid-based Monte Carlo Radiative Transfer code. The coupling is achieved by using the particle positions as generating sites for a Voronoi grid, and applying a precise mapping of particle-interpolated densities onto the grid cells that ensures mass conservation. The mapping, however, can be computationallyRead More →

Revisiting Bounds on Primordial Black Hole as Dark Matter with X-ray Backgroun Xiu-hui Tan, Jun-qing Xia arXiv:2404.17119v1 Announce Type: new Abstract: Within the mass range of $10^{16}-5times 10^{18}$ g, primordial black holes (PBHs) persist as plausible candidates for dark matter. Our study involves a reassessment of the constraints on PBHs through a comparative analysis of the cosmic X-ray background (CXB) and the emissions arising from their Hawking evaporation. We identify previously overlooked radiation processes across the relevant energy bands, potentially refining the bounds on PBHs. These processes encompass the direct emission from Hawking radiation, in-flight annihilation, the final state of radiation, and positronium annihilation. ThoroughRead More →

Improving flux ratio anomaly precision by measuring gravitational lens multipole moments with extended arcs Maverick S. H. Oh, Anna Nierenberg, Daniel Gilman, Simon Birrer arXiv:2404.17124v1 Announce Type: new Abstract: In a strong gravitational lens, perturbations by low-mass dark matter halos can be detected by differences between the measured image fluxes relative to the expectation from a smooth model for the mass distribution which contains only the gravitational effects of the main deflector. The abundance of these low-mass structures can be used to constrain the properties of dark matter. Traditionally only the lensed quasar positions have been to predict the smooth-model flux ratios. We demonstrate thatRead More →

Exploring the properties of photosphere and emission lines for tidal disruption events based on the global solution of slim disk and winds Yuehua Zhang, Qingwen Wu, Jiancheng Wu, Xinwu Cao, Weihua Lei arXiv:2404.17127v1 Announce Type: new Abstract: The theoretical debris supply rate from a tidal disruption of stars can exceed about one hundred times of the Eddington accretion rate for a $10^{6-7}M_{odot}$ supermassive black hole (SMBH). It is believed that a strong wind will be launched from the disk surface due to the radiation pressure in the case of super-Eddington accretion, which may be one of the mechanisms for formation of the envelope as observedRead More →

Bridging theory and observations in stellar pulsations: The impact of convection and metallicity on the instability strips of Classical and Type-II Cepheids Mami Deka, Earl P. Bellinger, Shashi M. Kanbur, Sukanta Deb, Anupam Bhardwaj, Hugh Riley Randall, Selim Kalici, Susmita Das arXiv:2404.17141v1 Announce Type: new Abstract: The effect of metallicity on the theoretical and empirical period-luminosity (PL) relations of Cepheid variables is not well understood and remains a highly debated issue. Here, we examine empirical colour-magnitude diagrams (CMDs) of Classical and Type-II Cepheids in the Magellanic Clouds and compare those with the theoretically predicted instability strip (IS) edges. We explore the effects of incorporating turbulentRead More →

Cosmology-independent Photon Mass Limits from Localized Fast Radio Bursts by using Artificial Neural Networks Jing-Yu Ran, Bao Wang, Jun-Jie Wei arXiv:2404.17154v1 Announce Type: new Abstract: A hypothetical photon mass, $m_{gamma}$, can produce a frequency-dependent vacuum dispersion of light, which leads to an additional time delay between photons with different frequencies when they propagate through a fixed distance. The dispersion measure–redshift measurements of fast radio bursts (FRBs) have been widely used to constrain the rest mass of the photon. However, all current studies analyzed the effect of the frequency-dependent dispersion for massive photons in the standard $Lambda$CDM cosmological context. In order to alleviate the circularity problemRead More →

Discovery of evolving low-frequency QPOs in hard X-rays ($sim 100$ keV) observed in black hole Swift J1727.8-1613 with $AstroSat$ Anuj Nandi (URSC), Santabrata Das (IIT Guwahati), Seshadri Majumder (IIT Guwahati), Tilak Katoch (TIFR), H. M. Antia (University of Mumbai), Parag Shah (TIFR) arXiv:2404.17160v1 Announce Type: new Abstract: We report the first detection of evolving Low-Frequency Quasi-periodic Oscillation (LFQPO) frequencies in hard X-rays upto $100$ keV with $AstroSat/LAXPC$ during `unusual’ outburst phase of Swift J1727.8-1613 in hard-intermediate state (HIMS). The observed LFQPO in $20 – 100$ keV has a centroid $nu_{_{rm QPO}}=1.43$ Hz, a coherence factor $Q= 7.14$ and an amplitude ${rm rms_{_{rm QPO}}} = 10.95%$Read More →

Detectability of axisymmetric magnetic fields from the core to the surface of oscillating post-main sequence stars Shatanik Bhattacharya (Tata Institute of Fundamental Research, Mumbai, India), Srijan Bharati Das (Center for Astrophysics – Harvard & Smithsonian, Cambridge, USA, Institute of Science and Technology Austria, Klosterneuburg, Austria), Lisa Bugnet (Institute of Science and Technology Austria, Klosterneuburg, Austria), Subrata Panda (Tata Institute of Fundamental Research, Mumbai, India), Shravan M. Hanasoge (Tata Institute of Fundamental Research, Mumbai, India) arXiv:2404.17167v1 Announce Type: new Abstract: Magnetic fields in the stellar interiors are key candidates to explain observed core rotation rates inside solar-like stars along their evolution. Recently, asteroseismic estimates of radialRead More →

Terrestrial planet formation from a ring: long-term simulations accounting for the giant planet instability J. M. Y. Woo, D. Nesvorny, J. Scora, A. Morbidelli arXiv:2404.17259v1 Announce Type: new Abstract: The process leading to the formation of the terrestrial planet remains elusive. In a previous publication, we have shown that, if the first generation of planetesimals forms in a ring at about 1 AU and the gas disk’s density peaks at the ring location, planetary embryos of a few martian masses can grow and remain in the ring. In this work, we extend our simulations beyond the gas-disk stage, covering 200 Myr and accounting for theRead More →

An improved correction of radial-velocity systematic for the SOPHIE spectrograph S. Grouffal, A. Santerne, N. C. Hara, I. Boisse, S. Coez, N. Heidari, S. Sulis arXiv:2404.17282v1 Announce Type: new Abstract: High precision spectrographs might exhibit temporal variations of their reference velocity or nightly zero point (NZP). One way to monitor the NZP is to measure bright stars, which are assumed to have an intrinsic radial velocity variation much smaller than the instrument’s precision. While this method is effective in most cases, it does not fully propagate the uncertainty arising from NZP variations. We present a new method to correct for NZP variations in radial-velocity timeRead More →

Bayesian insights in Tycho supernova remnant : a detailed mapping of ejecta properties L. Godinaud, F. Acero, A. Decourchelle, J. Ballet arXiv:2404.17296v1 Announce Type: new Abstract: While Tycho’s supernova remnant is one of the most studied type Ia Galactic supernova remnants, a global view of the physical properties of its ejecta is lacking, to understand its mysteries. In particular, the spatial distribution of the Si-rich ejecta line-of-sight velocity presents a large-scale unexplained asymmetry, with the north dominantly blueshifted and the south redshifted. To investigate the origin of this line-of-sight velocity asymmetry in the ejecta, we carry out a detailed X-ray spatially-resolved spectral analysis of theRead More →

Cepheid Metallicity in the Leavitt Law (C- MetaLL) survey: VI: Radial abundance gradients of 29 chemical species in the Milky Way Disk E. Trentin, G. Catanzaro, V. Ripepi, J. Alonso-Santiago, R. Molinaro, J. Storm, G. De Somma, M. Marconi, A. Bhardwaj, M. Gatto, I. Musella, V. Testa arXiv:2404.17299v1 Announce Type: new Abstract: Classical Cepheids (DCEPs) are crucial for calibrating the extragalactic distance ladder, ultimately enabling the determination of the Hubble constant through the PL and PW relations they exhibit. Hence it’s vital to understand how the PL and PW relations depend on metallicity. This is the purpose of the C-MetaLL survey within which this workRead More →

Energy Recovery System for Large Telescopes Aleksej Kiselev, Matthias Reichert, Tony Mroczkowski arXiv:2404.17311v1 Announce Type: new Abstract: In this paper, a kinetic energy recovery system for large telescopes is presented, with the Atacama Large Aperture Submm Telescope (AtLAST) as a possible target application. The system consists of supercapacitors integrated in the DC-link of motor inverters through a bidirectional DC-DC converter. The optimal system design, based on the energy flow analysis within the telescope’s power electronics, is introduced. The proposed system is simulated as part of the telescope’s drives, providing not only a significant reduction in energy consumption of the telescope due to motion, but alsoRead More →

Observation of a Fully-formed Forward–Reverse Shock Pair Due to the Interaction Between Two Coronal Mass Ejections at 0.5 au D. Trotta, A. Dimmock, X. Blanco-Cano, R. Forsyth, H. Hietala, N. Fargette, A. Larosa, N. Lugaz, E. Palmerio, S. W. Good, E. K. J. Kilpua, E. Yordanova, O. Pezzi, G. Nicolaou, T. S. Horbury, R. Vainio, N. Dresing, C. J. Owen, R. Wimmer-Schweingruber arXiv:2404.17315v1 Announce Type: new Abstract: We report direct observations of a fast magnetosonic forward–reverse shock pair observed by Solar Orbiter on March 8, 2022 at the short heliocentric distance of 0.5 au. The structure, sharing some features with fully-formed stream interaction regions (SIRs),Read More →

From infinite to infinitesimal: Using the Universe as a dataset to probe Casimir corrections to the vacuum energy from fields inhabiting the dark dimension Luis A. Anchordoqui, Ignatios Antoniadis, Dieter Lust, Neena T. Noble, Jorge F. Soriano arXiv:2404.17334v1 Announce Type: new Abstract: Promptly after high-resolution experiments harbinger the field of precision cosmology low- and high-redshift observations abruptly gave rise to a tension in the measurement of the present-day expansion rate of the Universe ($H_0$) and the clustering of matter ($S_8$). The statistically significant discrepancies between the locally measured values of $H_0$ and $S_8$ and the ones inferred from observations of the cosmic microwave background assumingRead More →

The SRG/eROSITA All-Sky Survey: Exploring halo assembly bias with X-ray selected superclusters A. Liu, E. Bulbul, T. Shin, A. von der Linden, V. Ghirardini, M. Kluge, J. S. Sanders, S. Grandis, X. Zhang, E. Artis, Y. E. Bahar, F. Balzer, N. Clerc, N. Malavasi, A. Merloni, K. Nandra, M. E. Ramos-Ceja, S. Zelmer arXiv:2404.17345v1 Announce Type: new Abstract: We explore halo assembly bias on cluster scales using large samples of superclusters. Leveraging the largest-ever X-ray galaxy cluster and supercluster samples obtained from the first SRG/eROSITA all-sky survey, we construct two subsamples of galaxy clusters which consist of supercluster members (SC) and isolated clusters (ISO) respectively.Read More →

ANAIS-112 three years data: a sensitive model independent negative test of the DAMA/LIBRA dark matter signal Iv’an Coarasa, Julio Amar’e, Jaime Apilluelo, Susana Cebri’an, David Cintas, Eduardo Garc’ia, Mar’ia Mart’inez, Miguel ‘Angel Oliv’an, Ysrael Ortigoza, Alfonso Ortiz de Sol’orzano, Tamara Pardo, Jorge Puimed’on, Ana Salinas, Mar’ia Luisa Sarsa, Patricia Villar arXiv:2404.17348v1 Announce Type: new Abstract: Weakly interacting massive particles (WIMPs) are well-motivated candidates for dark matter. One signature of galactic WIMPs is the annual modulation expected in a detector’s interaction rate, which arises from Earth’s rotation around the Sun. Over two decades, the DAMA/LIBRA experiment has observed such modulation with 250 kg of NaI(Tl) scintillators,Read More →

Archives of Photographic PLates for Astronomical USE (APPLAUSE) Digitisation of astronomical plates and their integration into the International Virtual Observatory Harry Enke, Taavi Tuvikene, Detlef Groote, Heinz Edelmann, Ulrich Heber arXiv:2404.17355v1 Announce Type: new Abstract: The Archives of Photographic PLates for Astronomical USE (APPLAUSE) project is aimed at digitising astronomical photographic plates from three major German plate collections, making them accessible through integration into the International Virtual Observatory (IVO). Photographic plates and related materials (logbooks, envelopes, etc.) were scanned with commercial flatbed scanners. Astrometric and photometric calibrations were carried out with the developed PyPlate software, using Gaia EDR3 data as a reference. The APPLAUSE dataRead More →

Inefficient star formation in high Mach number environments I. The turbulent support analytical model Patrick Hennebelle, No’e Brucy, Tine Colman arXiv:2404.17368v1 Announce Type: new Abstract: The star formation rate (SFR), the number of stars formed per unit of time, is a fundamental quantity in the evolution of the Universe. While turbulence is believed to play a crucial role in setting the SFR, the exact mechanism remains unclear. Turbulence promotes star formation by compressing the gas, but also slows it down by stabilizing the gas against gravity. Most widely-used analytical models rely on questionable assumptions, including: $i)$ integrating over the density PDF, a one-point statistical descriptionRead More →