cometadata/datacite-rtg-text-other-reclassification-records huggingface dataset:
Density functional theory of gas-liquid phase separation in dilute binary mixtures
Creators: name: Okamoto, Ryuichi
name: Onuki, Akira
Publisher: name: arXiv
Year: 2015
Subjects: subject: Soft Condensed Matter (cond-mat.soft)
subject: FOS: Physical sciences

description: We examine statics and dynamics of phase-separated states of dilute binary mixtures using density functional theory. In our systems, the difference in the salvation chemical potential $Δμ_s$ between liquid and gas is considerably larger than the thermal energy $k_BT$ for each solute particle and the attractive interaction among the solute particles is weaker than that among the solvent particles. In these conditions, the saturated vapor pressure increases by an amount equal to the solute density in liquid multiplied by the large factor $k_BT \exp(Δμ_s/k_BT)$. As a result, phase separation is induced at low solute densities in liquid and the new phase remains in gaseous states, while the liquid pressure is outside the coexistence curve of the solvent. This explains the widely observed formation of stable nanobubbles in ambient water with a dissolved gas. We calculate the density and stress profiles across planar and spherical interfaces, where the surface tension decreases with increasing the interfacial solute adsorption. We realize stable solute-rich bubbles with radius about 30 nm, which minimize the free energy functional. We then study dynamics around such a bubble after a decompression of the surrounding liquid, where the bubble undergoes a damped oscillation. In addition, we present some exact and approximate expressions for the surface tension and the interfacial stress tensor.
description: 16 pages, 13 figures
On Hadronization Phenomenology in Monte Carlo Event Generators
Creators: name: DUNCAN, CODY BENJAMIN
Publisher: name: Monash University
Year: 2020
Subjects: Particle physics

description: The Large Hadron Collider is a high-energy experiment that collides protons together, allowing us to study their substructure. The proton consists of particles called quarks that are bound together by gluons. At low energies, quarks and gluons have an increasingly strong interaction with each other, and consequently the usual tools available become inadequate. Instead, particle physicists rely on other methods, one of which is hadronization, a phenomenological approach that converts quarks and gluons into detectable composite particles - hadrons. This thesis studies hadronization and its importance in simulating high-energy collisions, and provides new extensions to the string and cluster model.
Aneurhynchus fragilis Nixon 1980
Creators: name: Notton, David G.
Publisher: name: Zenodo
Year: 2014
Subjects: Biodiversity
Taxonomy
Animalia
Arthropoda
Insecta
Hymenoptera
Diapriidae
Aneurhynchus
Aneurhynchus fragilis

description: Aneurhynchus fragilis Nixon, 1980: 23, fig. 60.
Valid name
Aneurhynchus fragilis Nixon, 1980.
Summary of types
Holotype ♀, BMNH number 9.814, by original designation.
Primary type data
England:/ Glos. E./ Badgeworth/ field mushroom/ 18.ix.1963; Pres. by/ A.Muncaster/ B.M.1963-697; Aneurhynchus / fragilis Nixon / type ♀ 1969.
Type locality
England, Gloucestershire, Badgeworth.
Remarks
The holotype is mounted on a card point, one antenna and the left mid leg are disarticulated, and the tips of three tarsi are lost.
description: Published as part of Notton, David G., 2014, A catalogue of the types of Diapriinae (Hymenoptera, Diapriidae) at the Natural History Museum, London, pp. 1-123 in European Journal of Taxonomy 75 on page 95, DOI: 10.5852/ejt.2014.75, http://zenodo.org/record/3862773
The Representation of Drought in Observations and Climate Models
Creators: name: HOFFMANN, DAVID
Publisher: name: Monash University
Year: 2020
Subjects: Atmospheric sciences not elsewhere classified

description: Drought is an inherent part of climate variability, significantly affecting ecosystems and economies. Effective monitoring of drought is crucial, and drought indices have been developed to do this by tracking variables such as precipitation, evaporation and soil moisture. However, indices are affected by uncertainties from measurements in observations and parametrizations in climate models. This thesis shows that given the uncertainties in measurements, precipitation alone is often sufficient for drought detection. The behaviour of the indices in climate models also reveal systematic limitations in the representation of drought processes, including an overestimation of the importance of evaporation for drought.
AST: A library for modelling and manipulating coordinate systems
Creators: name: Berry, David
name: Warren-Smith, Rodney
name: Jenness, Tim
Publisher: name: arXiv
Year: 2016
Subjects: subject: Instrumentation and Methods for Astrophysics (astro-ph.IM)
subject: FOS: Physical sciences

description: In view of increased interest in object-oriented systems for describing coordinate information, we present a description of the data model used by the Starlink AST library. AST provides a comprehensive range of facilities for attaching world co-ordinate systems to astronomical data, and for retrieving and interpreting that information in a variety of formats, including FITS-WCS. AST is a mature system that has been in use for more than 17 years, and may consequently be useful as a means of informing development of similar systems in the future.
The CARMENES search for exoplanets around M dwarfs. A sub-Neptunian mass planet in the habitable zone of HN Lib
Creators: name: González-Álvarez, E.
name: Kemmer, J.
name: Chaturvedi, P.
name: Caballero, J. A.
name: Quirrenbach, A.
name: Amado, P. J.
name: Béjar, V. J. S.
name: Cifuentes, C.
name: Herrero, E.
name: Kossakowski, D.
name: Reiners, A.
name: Ribas, I.
name: Rodríguez, E.
name: Rodríguez-López, C.
name: Sanz-Forcada, J.
name: Shan, Y.
name: Stock, S.
name: Tabernero, H. M.
name: Tal-Or, L.
name: Osorio, M. R. Zapatero
name: Hatzes, A. P.
name: Henning, Th.
name: López-González, M. J.
name: Montes, D.
name: Morales, J. C.
name: Pallé, E.
name: Pedraz, S.
name: Perger, M.
name: Reffert, S.
name: Sabotta, S.
name: Schweitzer, A.
name: Zechmeister, M.
Publisher: name: arXiv
Year: 2023
Subjects: subject: Earth and Planetary Astrophysics (astro-ph.EP)
subject: FOS: Physical sciences

description: We report the discovery of HN Lib b, a sub-Neptunian mass planet orbiting the nearby ($d \approx$ = 6.25 pc) M4.0 V star HN Lib detected by our CARMENES radial-velocity (RV) survey. We determined a planetary minimum mass of $M_\text{b}\sin i = $ 5.46 $\pm$ 0.75 $\text{M}_\oplus$ and an orbital period of $P_\text{b} = $ 36.116 $\pm$ 0.029 d, using $\sim$5 yr of CARMENES data, as well as archival RVs from HARPS and HIRES spanning more than 13 years. The flux received by the planet equals half the instellation on Earth, which places it in the middle of the conservative habitable zone (HZ) of its host star. The RV data show evidence for another planet candidate with $M_\text{[c]}\sin i = $ 9.7 $\pm$ 1.9 $\text{M}_\oplus$ and $P_\text{[c]} = $ 113.46 $\pm$ 0.20 d. The long-term stability of the signal and the fact that the best model for our data is a two-planet model with an independent activity component stand as strong arguments for establishing a planetary origin. However, we cannot rule out stellar activity due to its proximity to the rotation period of HN Lib, which we measured using CARMENES activity indicators and photometric data from a ground-based multi-site campaign as well as archival data. The discovery adds HN Lib b to the shortlist of super-Earth planets in the habitable zone of M dwarfs, but HN Lib [c] probably cannot be inhabited because, if confirmed, it would most likely be an icy giant.
M67 Blue Stragglers with High-resolution Infrared Spectroscopy
Creators: name: Brady, K. E.
name: Sneden, C.
name: Pilachowski, C. A.
name: Afşar, Melike
name: Mace, G. N.
name: Jaffe, D. T.
name: Gosnell, N. M.
name: Seifert, R.
Publisher: name: arXiv
Year: 2023
Subjects: subject: Solar and Stellar Astrophysics (astro-ph.SR)
subject: Astrophysics of Galaxies (astro-ph.GA)
subject: FOS: Physical sciences

description: We report on the first detailed infrared chemical analysis of five binary members (S277, S997, S975, S1031, and S1195) in the open cluster M67 (NGC 2682). These stars are located outside (bluer and/or brighter than) the main-sequence turnoff region in M67. High-resolution (R ~ 45,000) near-infrared spectra were obtained with the Immersion GRating INfrared Spectrograph (IGRINS) at the McDonald Observatory 2.7 m Harlan J. Smith Telescope, providing full spectral coverage of the H and K bands. The abundances of C, Na, Mg, Al, Si, S, Ca, Fe, and Ni are measured using neutral atomic absorption lines. We detect v sin i greater than or equal to 25 km s-1 in three of our program stars: S1031, S975, and S1195. We find our derived abundances to be in good agreement with turnoff star abundances, similar to published analyses of blue straggler stars in M67 from optical spectra. Detection of a carbon enhancement or depletion resulting from mass transfer is difficult due to the uncertainties in the carbon abundance and the relatively modest changes that may occur through red giant and asymptotic giant branch evolution.
Utilization of mechanical alloying method for flux growth of single crystalline BaFe$_2$(As$_{1-x}$P$_x$)$_2$
Creators: name: Takahashi, Kosuke Z.
name: Okuyama, Daisuke
name: Sato, Taku J.
Publisher: name: arXiv
Year: 2016
Subjects: subject: Superconductivity (cond-mat.supr-con)
subject: FOS: Physical sciences

description: Mechanical alloying method has been employed to prepare the Ba-Fe-As-P precursors, necessary for the Ba-(As,P) flux growth of the single crystalline BaFe$_2$(As$_{1-x}$P$_x$)$_2$. By alloying constituent elementals mechanically, the Ba-(As,P) precursors are successfully formed at the room temperature within one hour, significantly reducing preparation time. Using the mechanically alloyed precursors, we have grown single crystals of BaFe$_2$(As$_{1-x}$P$_x$)$_2$ with the sizes up to 5~mm $\times$ 5~mm $\times$ 0.1~mm.
description: 9 pages, 3 figures, 1 table
A unified framework for machine learning collective variables for enhanced sampling simulations: $\texttt{mlcolvar}$
Creators: name: Bonati, Luigi
name: Trizio, Enrico
name: Rizzi, Andrea
name: Parrinello, Michele
Publisher: name: arXiv
Year: 2023
Subjects: subject: Computational Physics (physics.comp-ph)
subject: FOS: Physical sciences

description: Identifying a reduced set of collective variables is critical for understanding atomistic simulations and accelerating them through enhanced sampling techniques. Recently, several methods have been proposed to learn these variables directly from atomistic data. Depending on the type of data available, the learning process can be framed as dimensionality reduction, classification of metastable states or identification of slow modes. Here we present $\texttt{mlcolvar}$, a Python library that simplifies the construction of these variables and their use in the context of enhanced sampling through a contributed interface to the PLUMED software. The library is organized modularly to facilitate the extension and cross-contamination of these methodologies. In this spirit, we developed a general multi-task learning framework in which multiple objective functions and data from different simulations can be combined to improve the collective variables. The library's versatility is demonstrated through simple examples that are prototypical of realistic scenarios.
Investigating the Air Stability of As-Grown and Intercalated 2D Materials for Future Electronics
Creators: name: KOTSAKIDIS, JIMMY CHRISTOPHER
Publisher: name: Monash University
Year: 2020
Subjects: Condensed matter physics not elsewhere classified
Structural properties of condensed matter
Surface properties of condensed matter

description: The two-dimensional (2D) materials graphene and monolayer WS2 have demonstrated exciting physics that may lead to new electronic and optical devices. Furthermore, the modification of materials such as graphene via intercalation (insertion of atoms between graphene sheets, or between graphene and supporting substrate), have offered significant insight into basic physical phenomena such as superconductivity in calcium-intercalated graphene. Yet the details surrounding their reaction with ambient atmosphere – which is critical for their technological implementation – is largely lacking. Thus, in this thesis, I seek to elucidate the ambient air reaction of monolayer WS2 and alkaline earth (Mg/Ca) intercalated epitaxial graphene on silicon carbide.
Tormund's return: Hints of quasi-periodic eruption features from a recent optical tidal disruption event
Creators: name: Quintin, E.
name: Webb, N. A.
name: Guillot, S.
name: Miniutti, G.
name: Kammoun, E. S.
name: Giustini, M.
name: Arcodia, R.
name: Soucail, G.
name: Clerc, N.
name: Amato, R.
name: Markwardt, C. B.
Publisher: name: arXiv
Year: 2023
Subjects: subject: High Energy Astrophysical Phenomena (astro-ph.HE)
subject: FOS: Physical sciences

description: Quasi-periodic eruptions (QPEs) are repeating thermal X-ray bursts associated with accreting massive black holes, the precise underlying physical mechanisms of which are still unclear. We present a new candidate QPE source, AT 2019vcb (nicknamed Tormund by the ZTF collaboration), which was found during an archival search for QPEs in the XMM-Newton archive. It was first discovered in 2019 as an optical tidal disruption event (TDE) at $z=0.088$, and its X-ray follow-up exhibited QPE-like properties. Our goals are to verify its robustness as QPE candidate and to investigate its properties to improve our understanding of QPEs. We performed a detailed study of the X-ray spectral behaviour of this source over the course of the XMM-Newton archival observation. We also report on recent Swift and NICER follow-up observations to constrain the source's current activity and overall lifetime, as well as an optical spectral follow-up. The first two Swift detections and the first half of the 30 ks XMM-Newton exposure of Tormund displayed a decaying thermal emission typical of an X-ray TDE. However, the second half of the exposure showed a dramatic rise in temperature (from 53 to 114 eV) and 0.2-2 keV luminosity (from $3.2\times10^{42}$ to $1.2\times10^{44}$ erg s$^{-1}$). The late-time NICER follow-up indicates that the source is still X-ray bright more than three years after the initial optical TDE. Although only a rise phase was observed, Tormund's strong similarities with a known QPE source (eRO-QPE1) and the impossibility to simultaneously account for all observational features with alternative interpretations allow us to classify Tormund as a candidate QPE. If confirmed as a QPE, it would further strengthen the observational link between TDEs and QPEs. It is also the first QPE candidate for which an associated optical TDE was directly observed, constraining the formation time of QPEs.
description: Accepted for publication in A&A, 20 pages, 17 figures
THz conductivity of Sr$_{1-x}$Ca$_x$RuO$_3$
Creators: name: Geiger, Diana
name: Pracht, Uwe S.
name: Dressel, Martin
name: Mravlje, Jernej
name: Schneider, Melanie
name: Gegenwart, Philipp
name: Scheffler, Marc
Publisher: name: arXiv
Year: 2016
Subjects: subject: Strongly Correlated Electrons (cond-mat.str-el)
subject: FOS: Physical sciences

description: We investigate the optical conductivity of Sr$_{1-x}$Ca$_x$RuO$_3$ across the ferromagnetic to paramagnetic transition that occurs at $x=0.8$. The thin films were grown by metalorganic aerosol deposition with $0 \leq x \leq 1$ onto NdGaO$_3$ substrates. We performed THz frequency domain spectroscopy in a frequency range from 3~cm$^{-1}$ to 40~cm$^{-1}$ (100~GHz to 1.4~THz) and at temperatures ranging from 5~K to 300~K, measuring transmittivity and phase shift through the films. From this we obtained real and imaginary parts of the optical conductivity. The end-members, ferromagnetic SrRuO$_3$ and paramagnetic CaRuO$_3$, show a strongly frequency-dependent metallic response at temperatures below 20~K. Due to the high quality of these samples we can access pronounced intrinsic electronic contributions to the optical scattering rate, which at 1.4~THz exceeds the residual scattering rate by more than a factor of three. Deviations from a Drude response start at about 0.7~THz for both end-members in a remarkably similar way. For the intermediate members a higher residual scattering originating in the compositional disorder leads to a featureless optical response, instead. The relevance of low-lying interband transitions is addressed by a calculation of the optical conductivity within density functional theory in the local density approximation (LDA).
A new smoothed particle hydrodynamics method based on high-order moving-least-square targeted essentially non-oscillatory scheme for compressible flows
Creators: name: Gao, Tianrun
name: Liang, Tian
name: Fu, Lin
Publisher: name: arXiv
Year: 2023
Subjects: subject: Fluid Dynamics (physics.flu-dyn)
subject: Computational Physics (physics.comp-ph)
subject: FOS: Physical sciences
subject: 76N06, 76N15, 65M22, 76M28, 65N75

description: In this study, we establish a hybrid high-order smoothed particle hydrodynamics (SPH) framework (MLS-TENO-SPH) for compressible flows with discontinuities, which is able to achieve genuine high-order convergence in smooth regions and also capture discontinuities well in non-smooth regions. The framework can be either fully Lagrangian, Eulerian or realizing arbitary-Lagrangian-Eulerian (ALE) feature enforcing the isotropic particle distribution in specific cases. In the proposed framework, the computational domain is divided into smooth regions and non-smooth regions, and these two regions are determined by a strong scale separation strategy in the targeted essentially non-oscillatory (TENO) scheme. In smooth regions, the moving-least-square (MLS) approximation is used for evaluating high-order derivative operator, which is able to realize genuine high-order construction; in non-smooth regions, the new TENO scheme based on Vila's framework with several new improvements will be deployed to capture discontinuities and high-wavenumber flow scales with low numerical dissipation. The present MLS-TENO-SPH method is validated with a set of challenging cases based on the Eulerian, Lagrangian or ALE framework. Numerical results demonstrate that the MLS-TENO-SPH method features lower numerical dissipation and higher efficiency than the conventional method, and can restore genuine high-order accuracy in smooth regions. Overall, the proposed framework serves as a new exploration in high-order SPH methods, which are potential for compressible flow simulations with shockwaves.
description: 36 pages, 15 figures, accepted by Journal of Computational Physics on June 1st, 2023
Long-term optical spectral monitoring of a changing-look active galactic nucleus NGC 3516 -- II. Broad-line profile variability
Creators: name: Popović, Luka C.
name: Ilić, Dragana
name: Burenkov, Alexander
name: Álvarez, Victor Manuel Patiño
name: Marceta-Mandić, Sladjana
name: Dojcinović, Jelena Kovacević -
name: Shablovinskaya, Elena
name: Kovacević, Andjelka B.
name: Marziani, Paola
name: Chavushyan, Vahram
name: Wang, Jian-Min
name: Li, Yan-Rong
name: Mediavilla, Evencio G.
Publisher: name: arXiv
Year: 2023
Subjects: subject: Astrophysics of Galaxies (astro-ph.GA)
subject: Cosmology and Nongalactic Astrophysics (astro-ph.CO)
subject: FOS: Physical sciences

description: We analyze the broad H$β$ line profile variability of the "changing look" active galactic nucleus (CL-AGN) NGC 3516 over a long period of 25 years. The observed change in the broad line profile may indicate a change in the geometry of the broad line region (BLR). Using spectral line profiles, we aim to explore changes in the kinematics and dimensions of the BLR in NGC 3516. We consider two possible scenarios, i.e. changes in the broad-line emission are caused by a decrease of ionization continuum emission or by the BLR obscuration by outer dusty regions. With this investigation we aim to clarify the CL mechanism of this AGN. We analyze the spectral band around the H$β$ line as well as the broad H$β$ line parameters, and how they change in time. We model the broad-line profiles assuming that there is an emission from the accretion disc superposed with an emission from a surrounding region that is outside the disc. We find that in the Type 1 activity phase, the BLR is very complex. There is a clear disc-like BLR that contributes to the broad line wings and an additional intermediate line region (ILR) that contributes to the line core. In the high activity phase, the ILR emission is close to the center of the line (in some cases slightly shifted to the red), whereas in the low activity phase (i.e., Type 2 phase), the ILR component has a significant shift to the blue, indicating an outflow. We propose that the changing look mechanism in NGC 3516 is rather connected with the intrinsic effects than with an outer obscuring region. It may still be possible that the dust has an important role in the low activity phase when it is coming inside of the BLR, making a dusty BLR. In this way, it causes a decrease in the ionization and recombination rates.
description: 16 pages, accepted in A&A
Unveiling a universal relationship between the f(R) parameter and neutron star properties
Creators: name: Nobleson, K.
name: Banik, Sarmistha
name: Malik, Tuhin
Publisher: name: arXiv
Year: 2023
Subjects: subject: General Relativity and Quantum Cosmology (gr-qc)
subject: FOS: Physical sciences

description: In recent years, modified gravity theories have gained significant attention as potential replacements for the general theory of relativity. Neutron stars, which are dense compact objects, provide ideal astrophysical laboratories for testing these theories. However, understanding the properties of neutron stars within the framework of modified gravity theories requires careful consideration of the presently known uncertainty of equations of state (EoS) that describe the behavior of matter at extreme densities. In this study, we investigate three realistic EoS generated using a relativistic mean field framework, which covers the currently known uncertainties in the stiffness of neutron star matter. We then employ a Bayesian approach to statistically analyze the posterior distribution of the free parameter $α$ of the $f(R)$ gravity model, specifically $f(R) = R + αR^2$. By using this approach, we are able to account for our limited understanding of the interiors of neutron stars as well as the uncertainties associated with the modified gravity theory. We impose observational constraints on our analysis, including the maximum mass, and the radius of a neutron star with a mass of $1.4 M_{\odot}$ and $2.08 M_{\odot}$, which are obtained from X-ray NICER observations. By considering these constraints, we are able to robustly investigate the relationship between the $f(R)$ gravity model parameter $α$ and the maximum mass of neutron stars. Our results reveal a universality relationship between the $f(R)$ gravity model parameter $α$ and the maximum mass of neutron stars. This relationship provides insights into the behavior of neutron stars in modified gravity theories and helps us understand the degeneracies arising from our current limited knowledge of the interiors of neutron stars and the free parameter $α$ of the modified gravity theory.
description: 10 pages, 7 figures, 3 tables
Theoretical light curve models of the symbiotic nova CN Cha -- Optical flat peak for three years
Creators: name: Kato, Mariko
name: Hachisu, Izumi
Publisher: name: arXiv
Year: 2023
Subjects: subject: Solar and Stellar Astrophysics (astro-ph.SR)
subject: High Energy Astrophysical Phenomena (astro-ph.HE)
subject: FOS: Physical sciences

description: CN Cha is a slow symbiotic nova characterized by a three-years-long optical flat peak followed by a rapid decline. We present theoretical light curves for CN Cha, based on hydrostatic approximation, and estimate the white dwarf (WD) mass to be $\sim 0.6 ~M_\odot$ for a low metal abundance of Z = 0.004. This kind of flat peak novae are border objects between classical novae having a sharp optical peak and extremely slow novae, the evolutions of which are too slow to be recognized as a nova outburst in human timescale. Theoretically, there are two types of nova envelope solutions, static and optically-thick wind, in low mass WDs ($\lesssim 0.7 ~M_\odot$). Such a nova outburst begins first in a hydrostatic manner, and later it could change to an optically-thick wind evolution due to perturbation by the companion star in the nova envelope. Multiple peaks are a reflection of the relaxation process of transition. CN Cha supports our explanation on the difference between long-lasted flat peak novae like CN Cha and multiple peak novae like V723 Cas, because the companion star is located far outside, and does not perturb, the nova envelope in CN Cha.
description: 9 pages, 4 figures, to appear in ApJ
title: Comparative thermal analyses of solar milk pasteurizers integrated with solar concentrator and evacuated tube collector
Creators: name: Khan, Khawar Saeed
name: Latif, Yasir
name: Munir, Anjum
name: Hensel, Oliver
Publisher: name: Universität Kassel
Year: 2022
Subjects: subject: solar milk pasteurization
subject: evacuated tube collector
subject: paraboloidal concentrator
subject: steam receiver
subject: thermal analyses
subject: milk processing at off grid locations
subject: 630
subject: Pakistan
subject: Pasteurisieren
subject: Nachhaltigkeit
subject: Solartechnik
subject: Energieeffizienz
subject: Milchwirtschaft
subject: Kostensenkung
subject: Milchversorgung
subject: Erneuerbare Energien
subject: Thermoanalyse
subject: Supply Chain Management

description: Gefördert durch den Publikationsfonds der Universität Kassel
On the simulation of arterial road networks
Creators: name: M, SAMITHREE PRASADIKA RAJAPAKSHA SAMARANAYAKA RAJAPAKSHA
Publisher: name: Monash University
Year: 2020
Subjects: Applied statistics

description: Traffic simulation models have become an increasingly important tool for investigating vehicular dynamics in arterial networks. In this thesis, we study three distinct, but related, topics in the field of traffic simulation. Specifically, we study calibration of traffic models via Approximate Bayesian Computation (ABC); the form of link travel time distributions, particularly in the presence of traffic lights; and the form of dwell time distributions for on-road public transport, in particular, for trams.
CHEX-MATE: Characterization of the intra-cluster medium temperature distribution
Creators: name: Lovisari, L.
name: Ettori, S.
name: Rasia, E.
name: Gaspari, M.
name: Bourdin, H.
name: Campitiello, M. G.
name: Rossetti, M.
name: Bartalucci, I.
name: De Grandi, S.
name: De Luca, F.
name: De Petris, M.
name: Eckert, D.
name: Forman, W.
name: Gastaldello, F.
name: Ghizzardi, S.
name: Jones, C.
name: Kay, S.
name: Kim, J.
name: Maughan, B. J.
name: Mazzotta, P.
name: Pointecouteau, E.
name: Pratt, G. W.
name: Sayers, J.
name: Sereno, M.
name: Simonte, M.
name: Tozzi, P.
Publisher: name: arXiv
Year: 2023
Subjects: subject: Cosmology and Nongalactic Astrophysics (astro-ph.CO)
subject: Astrophysics of Galaxies (astro-ph.GA)
subject: FOS: Physical sciences

description: We study the perturbations in the temperature (and density) distribution for 28 clusters selected from the CHEX-MATE sample to evaluate and characterize the level of inhomogeneities and the related dynamical state of the ICM. We use these spatially resolved 2D distributions to measure the global and radial scatter and identify the regions that deviate the most from the average distribution. During this process, we introduce three dynamical state estimators and produce clean temperature profiles after removing the most deviant regions. We find that the temperature distribution of most of the clusters is skewed towards high temperatures and is well described by a log-normal function. There is no indication that the number of regions deviating more than 1$σ$ from the azimuthal value is correlated with the dynamical state inferred from morphological estimators. The removal of these regions leads to local temperature variations up to 10-20% and an average increase of $\sim$5% in the overall cluster temperatures. The measured relative intrinsic scatter within $R_{500}$, $σ_{T,int}/T$, has values of 0.17$^{+0.08}_{-0.05}$, and is almost independent of the cluster mass and dynamical state. Comparing the scatter of temperature and density profiles to hydrodynamic simulations, we constrain the average Mach number regime of the sample to $M_{3D}$=0.36$^{+0.16}_{-0.09}$. We infer the ratio between the energy in turbulence and the thermal energy, and translate this ratio in terms of a predicted hydrostatic mass bias $b$, estimating an average value of $b\sim$0.11 (covering a range between 0 and 0.37) within $R_{500}$. This study provides detailed temperature fluctuation measurements for 28 CHEX-MATE clusters which can be used to study turbulence, derive the mass bias, and make predictions on the scaling relation properties.
description: Accepted for publication in A&A
Hypoxia-resistance heterogeneity in tumours: the impact of geometrical characterization of environmental niches and evolutionary trade-offs. A mathematical approach
Creators: name: Chiari, Giulia
name: Fiandaca, Giada
name: Delitala, Marcello Edoardo
Publisher: name: arXiv
Year: 2023
Subjects: subject: Populations and Evolution (q-bio.PE)
subject: Numerical Analysis (math.NA)
subject: Analysis of PDEs (math.AP)
subject: Medical Physics (physics.med-ph)
subject: FOS: Biological sciences
subject: FOS: Mathematics
subject: FOS: Physical sciences

description: In the study of cancer evolution and therapeutic strategies, scientific evidence shows that a key dynamics lies in the tumor-environment interaction. In particular, oxygen concentration plays a central role in the determination of the phenotypic heterogeneity of cancer cell populations, whose qualitative and geometric characteristics are predominant factors in the occurrence of relapses and failure of eradication. We propose a mathematical model able to describe the eco-evolutionary spatial dynamics of tumour cells in their adaptation to hypoxic microenvironments. As a main novelty with respect to the existing literature, we combine a phenotypic indicator reflecting the experimentally-observed metabolic trade-off between the hypoxia-resistance ability and the proliferative potential with a 2d geometric domain, without the constraint of radial symmetry. The model is settled in the mathematical framework of phenotype-structured population dynamics and it is formulated in terms of systems of coupled non-linear integro-differential equations. The computational outcomes demonstrate that hypoxia-induced selection results in a geometric characterization of phenotypic-defined tumour niches that impact on tumour aggressiveness and invasive ability. Furthermore, results show how the knowledge of environmental characteristics provides a predictive advantage on tumour mass development in terms of size, shape, and composition.
Rigidity of transmembrane proteins determines their cluster shape
Creators: name: Jafarinia, Hamidreza
name: Khoshnood, Atefeh
name: Jalali, Mir Abbas
Publisher: name: arXiv
Year: 2015
Subjects: subject: Biological Physics (physics.bio-ph)
subject: Soft Condensed Matter (cond-mat.soft)
subject: FOS: Physical sciences

description: Protein aggregation in cell membrane is vital for the majority of biological functions. Recent experimental results suggest that transmembrane domains of proteins such as $α$-helices and $β$-sheets have different structural rigidities. We use molecular dynamics simulation of a coarse-grained model of protein-embedded lipid membranes to investigate the mechanisms of protein clustering. For a variety of protein concentrations, our simulations under thermal equilibrium conditions reveal that the structural rigidity of transmembrane domains dramatically affects interactions and changes the shape of the cluster. We have observed stable large aggregates even in the absence of hydrophobic mismatch which has been previously proposed as the mechanism of protein aggregation. According to our results, semi-flexible proteins aggregate to form two-dimensional clusters while rigid proteins, by contrast, form one-dimensional string-like structures. By assuming two probable scenarios for the formation of a two-dimensional triangular structure, we calculate the lipid density around protein clusters and find that the difference in lipid distribution around rigid and semiflexible proteins determines the one- or two-dimensional nature of aggregates. It is found that lipids move faster around semiflexible proteins than rigid ones. The aggregation mechanism suggested in this paper can be tested by current state-of-the-art experimental facilities.
description: 8 pages, 6 figures. Accepted for publication in Physical Review E
KMZ file for: Slow-moving landslides triggered by the 2016 Mw 7.8 Kaikōura earthquake, New Zealand
Creators: name: Yunmeng Cao
Publisher: name: Zenodo
Year: 2023
Subjects: Slow-moving landslide
2016 Mw7.8 Kaikōura earthquake
InSAR
Time-series InSAR
InSAR phase-gradient

description: Pre- and post-seismic velocity KMZs of the detected twenty-one large slow-moving landslides triggered by the 2016 Mw7.8 Kaikōura earthquake, New Zealand. The results were from Sentinel-1 time-series analysis using a new InSAR-phase-gradient based time-series approach (submitted to Geophysical Research Letters by Cao et al., 2023). Each point in the KMZ file includes: 1) deformation velocity (pre- or post-seismic), 2) temporal coherence of the estimated time-series (pre- or post-seismic), 3) location (latitude and longitude). Region of the presented points for each landslide is the approximate edge of the sliding-area.
description: {"references": ["Cao et al., 2023, Slow-moving landslides triggered by the 2016 Mw 7.8 Kaik\u014dura earthquake, New Zealand: a new InSAR phase-gradient based time-series approach. https://essopenarchive.org/doi/full/10.1002/essoar.10512014.1"]}
The post-disk (or primordial) spin distribution of M dwarf stars
Creators: name: Gehrig, L.
name: Gaidos, E.
name: Güdel, M.
Publisher: name: arXiv
Year: 2023
Subjects: subject: Solar and Stellar Astrophysics (astro-ph.SR)
subject: Earth and Planetary Astrophysics (astro-ph.EP)
subject: FOS: Physical sciences

description: We investigate the influence of an accretion disk on the angular momentum (AM) evolution of young M dwarfs, which parameters govern the AM distribution after the disk phase, and whether this leads to a mass-independent distribution of SAM. We find that above an initial rate $\dot{M}_\mathrm{crit} \sim 10^{-8}~\mathrm{M_\odot/yr}$ accretion "erases" the initial SAM of M dwarfs during the disk lifetime, and stellar rotation converges to values of SAM that are largely independent of initial conditions. For stellar masses $> 0.3~\mathrm{M_\odot}$, we find that observed initial accretion rates $\dot{M}_\mathrm{init}$ are comparable to or exceed $\dot{M}_\mathrm{crit}$. Furthermore, stellar SAM after the disk phase scales with the stellar magnetic field strength as a power-law with an exponent of $-1.1$. For lower stellar masses, $\dot{M}_\mathrm{init}$ is predicted to be smaller than $\dot{M}_\mathrm{crit}$ and the initial conditions are imprinted in the stellar SAM after the disk phase. To explain the observed mass-independent distribution of SAM, the stellar magnetic field strength has to range between 20~G and 500~G (700~G and 1500~G) for a 0.1~$\mathrm{M_\odot}$ (0.6~$\mathrm{M_\odot}$) star. These values match observed large-scale magnetic field measurements of young M~dwarfs and the positive relation between stellar mass and magnetic field strength agrees with a theoretically-motivated scaling relation. The scaling law between stellar SAM, mass, and the magnetic field strength is consistent for young stars, where these parameters are constrained by observations. Due to the very limited number of available data, we advocate for efforts to obtain more such measurements. Our results provide new constraints on the relation between stellar mass and magnetic field strength and can be used as initial conditions for future stellar spin models, starting after the disk phase. (shortened)
description: accepted for publication in A&A
Current status and operation of the H.E.S.S. array of imaging atmospheric Cherenkov telescopes
Creators: name: Ohm, S.
name: Wagner, S.
Publisher: name: arXiv
Year: 2023
Subjects: subject: Instrumentation and Methods for Astrophysics (astro-ph.IM)
subject: High Energy Astrophysical Phenomena (astro-ph.HE)
subject: FOS: Physical sciences

description: The High Energy Stereoscopic System (H.E.S.S.) is an array of five imaging atmospheric Cherenkov telescopes (IACTs) to study gamma-ray emission from astrophysical objects in the Southern hemisphere. It is the only hybrid array of IACTs, composed of telescopes with different collection areas and footprints, individually optimised for a specific energy range. Collectively, the array is most sensitive to gamma rays in the range of 100 GeV to 100 TeV. The array has been in operation since 2002 and has been upgraded with new telescopes and cameras multiple times. Recent hardware upgrades and changes in the operational procedures increased the amount of observing time, which is of key importance for time-domain science. H.E.S.S. operations saw record data taking in 2020 and 2021 and we describe the current operations with specific emphasis on system performance, operational processes and workflows, quality control, and (near) real-time extraction of science results. In light of this, we will briefly discuss the early detection of gamma-ray emission from the recurrent nova RS Oph and alert distribution to the astrophysics community.
description: Proceeding for contributed talk at RICH 2022 conference, Edinburgh, September 2022. 4 pages, 5 figures, accepted for publication in NIM A
On Elliptic Algebras and Large-n Supersymmetric Gauge Theories
Creators: name: Koroteev, Peter
name: Sciarappa, Antonio
Publisher: name: arXiv
Year: 2016
Subjects: subject: High Energy Physics - Theory (hep-th)
subject: Mathematical Physics (math-ph)
subject: Quantum Algebra (math.QA)
subject: Representation Theory (math.RT)
subject: FOS: Physical sciences
subject: FOS: Mathematics

description: In this note we further develop the duality between supersymmetric gauge theories in various dimensions and elliptic integrable systems such as Ruijsenaars-Schneider model and periodic intermediate long wave hydrodynamics. These models arise in instanton counting problems and are described by certain elliptic algebras. We discuss the correspondence between the two types of models by employing the large-n limit of the dual gauge theory. In particular we provide non-Abelian generalization of our previous result on the intermediate long wave model.
description: 45 pages, 2 figures
Dating young open clusters using delta Scuti stars. Results for Trumpler 10 and Praesepe
Creators: name: Ortega, D. Pamos
name: Mirouh, G. M.
name: Hernández, A. García
name: Yanes, J. C. Suárez
name: Forteza, S. Barceló
Publisher: name: arXiv
Year: 2023
Subjects: subject: Solar and Stellar Astrophysics (astro-ph.SR)
subject: Astrophysics of Galaxies (astro-ph.GA)
subject: FOS: Physical sciences

description: Aims. The main goal of this work is to date young open clusters using $δ$ Sct stars. Seismic indices such as the large separation and the frequency at maximum power can help to constrain the models to better characterise the stars. We propose a reliable method to identify some radial modes, which gives us greater confidence in the constrained models. Methods. We extract the frequency content of a sample of $δ$ Sct stars belonging to the same open cluster. We estimate the low-order large separation by means of different techniques and the frequency at maximum power for each member of the sample. We use a grid of models built with the typical parameters of $δ$ Sct stars, including mass, metallicity and rotation as independent variables, and determine the oscillation modes. We select the observed frequencies whose ratios match those of the models. Once we find a range of radial modes matching the observed frequencies, mainly the fundamental mode, we add it to the other seismic parameters to derive the stellar age. Assuming star groups have similar chemistry and age, we estimate their mean age by computing a weighted probability density function fit to the age distribution of the seismically constrained models. Results. We estimate the age of Trumpler 10 to be $30_{-20}{+30}$ Myr, and that of Praesepe to be $580 \pm 230$ Myr. In this latter case, we find two apparent populations of $δ$ Sct stars in the same cluster, one at $510 \pm 140$ Myr and another at $890 \pm 140$ Myr. This may be due to two different formation events, different rotational velocities of the members in our sample of stars (as rapid rotation may modify the observed large separation), or to membership of unresolved binary systems.
description: 20 pages, 25 figure, uses the open-source code MultiModes (see https://github.com/davidpamos/MultiModes). It will be published in A&A
Simulation and analytical modeling of high-speed droplet impact onto a surface
Creators: name: Liu, Yanchao
name: Chu, Xu
name: Yang, Guang
name: Weigand, Bernhard
Publisher: name: arXiv
Year: 2023
Subjects: subject: Fluid Dynamics (physics.flu-dyn)
subject: FOS: Physical sciences

description: The fluid dynamics of liquid droplet impact on surfaces hold significant relevance to various industrial applications. However, high impact velocities introduce compressible effects, leading to material erosion. A gap in understanding and modeling these effects has motivated this study. We simulated droplet impacts on surfaces and proposed a new analytical model for impact pressure and droplet turning line, targeting at predictions for enhanced cavitation. The highly compressed liquid behind the droplet expands sideways, causing lateral jetting. As the droplet encounters a shock wave, it reflects as a rarefaction wave, leading to low-pressure zones within the droplet. These zones converge at the droplet's center, causing cavitation, which, upon collapse, induces another shock wave, contributing to erosion. Using the well-established model for the low-velocity impact shows a significant discrepancy. Hence, an analytical model for the turning line radius is introduced, incorporating the lateral jetting's characteristic length scale. Comparing our model with existing ones, our new model exhibits superior predictive accuracy.
Probing the Heart of Active Narrow-line Seyfert 1 Galaxies with VERA Wideband Polarimetry
Creators: name: Takamura, Mieko
name: Hada, Kazuhiro
name: Honma, Mareki
name: Oyama, Tomoaki
name: Yamauchi, Aya
name: Suzuki, Syunsaku
name: Hagiwara, Yoshiaki
name: Orienti, Monica
name: D'Ammando, Filippo
name: Park, Jongho
name: Kam, Minchul
name: Doi, Akihiro
Publisher: name: arXiv
Year: 2023
Subjects: subject: High Energy Astrophysical Phenomena (astro-ph.HE)
subject: Astrophysics of Galaxies (astro-ph.GA)
subject: FOS: Physical sciences

description: We explored the parsec-scale nuclear regions of a sample of radio-loud narrow-line Seyfert 1 galaxies (NLSy1s) using the VLBI Exploration of Radio Astronomy (VERA) wideband (at a recording rate of $16\,\mathrm{Gbps}$) polarimetry at 22 and 43 GHz. Our targets include 1H 0323+342, SBS 0846+513, PMN J0948+0022, 1219+044, PKS 1502+036 and TXS 2116-077, which are all known to exhibit $γ$-ray emission indicative of possessing highly beamed jets similar to blazars. For the first time, we unambiguously detected Faraday rotation toward the parsec-scale radio core of NLSy1s, with a median observed core rotation measure (RM) of $2.7\times 10^3\,{\rm rad\,m^{-2}}$ (or $6.3\times 10^3\,{\rm rad\,m^{-2}}$ for redshift-corrected). This level of RM magnitude is significantly larger than those seen in the core of BL Lac objects (BLOs; a dominant subclass of blazars), suggesting that the nuclear environment of NLSy1s is more gas-rich than that in BLOs. Interestingly, the observed parsec-scale polarimetric properties of NLSy1s (low core fractional polarization, large core RM and jet-EVPA misalignment) are rather similar to those of flat-spectrum radio quasars (FSRQs). Our results are in accordance with the scenario that NLSy1s are in an early stage of AGN evolution with their central black hole masses being smaller than those of more evolved FSRQs.
description: 22 pages, 11 figures, 7 tables. Accepted for publication in ApJ
Chemodynamical study of two CEMP-no stars from the Hamburg/ESO Survey
Creators: name: Shejeelammal, J.
name: Goswami, Aruna
Publisher: name: arXiv
Year: 2023
Subjects: subject: Solar and Stellar Astrophysics (astro-ph.SR)
subject: Astrophysics of Galaxies (astro-ph.GA)
subject: FOS: Physical sciences

description: The Carbon-Enhanced Metal-Poor (CEMP) stars with no enhancement of neutron-capture elements, the so-called CEMP-no stars are believed to be the direct descendants of first-generation stars and provide a unique opportunity to probe the early Galactic nucleosynthesis. We present a detailed chemical and kinematic analysis for two extremely metal-poor stars HE1243$-$2408 and HE0038$-$0345 using high-resolution (R${\sim}$86,000) HERMES spectra. For the object HE1243$-$2408, we could make a detailed comparison with the available literature values; however, only limited information is available for the other object HE0038$-$0345. Our estimated metallicity for these two objects are $-$3.05 and $-$2.92 respectively. With estimated [C/Fe] (1.03 and 1.05) and [Ba/Fe] ($-$0.18 and $-$0.11) respectively, the objects are found to be bonafide CEMP-no stars. From the observed abundances of C, Na, Mg, and Ba (i.e., A(C), A(Na), A(Mg), A(Ba)), the objects are found to belong to Group II CEMP-no stars. A detailed abundance profile analysis indicates that the objects are accreted from dSph satellite galaxies that support hierarchical Galaxy assembly. Further, our analysis shows that the progenitors of the stars are likely Pop II Core-Collapse Supernovae. The object HE0038$-$0345 is found to be a high-energy, prograde, outer-halo object, and HE1243$-$2408 is found to be a high-energy, retrograde, inner-halo object. Our detailed chemodynamical analysis shows that HE1243$-$2408 is related to I'itoi structure, where as HE0038$-$0345 is likely related to Sgr or GSE events. The mass of the progenitor galaxies of the program stars inferred from their dynamics is at par with their likely origin in massive dSph galaxies.