cometadata/datacite-rtg-text-other-reclassification-records huggingface dataset:
A correlation between accreted stellar kinematics and dark matter halo spin in the ARTEMIS simulations
Creators: name: Dillamore, Adam M.
name: Belokurov, Vasily
name: Evans, N. Wyn
name: Font, Andreea S.
Publisher: name: arXiv
Year: 2022
Subjects: subject: Astrophysics of Galaxies (astro-ph.GA)
subject: FOS: Physical sciences

description: We report a correlation between the presence of a Gaia-Sausage-Enceladus (GSE) analogue and dark matter halo spin in the ARTEMIS simulations of Milky Way-like galaxies. The haloes which contain a large population of accreted stars on highly radial orbits (like the GSE) have lower spin on average than their counterparts with more isotropic stellar velocity distributions. The median modified spin parameters $λ^\prime$ differ by a factor of $\sim1.7$ at the present-day, with a similar value when the haloes far from virial equilibrium are removed. We also show that accreted stars make up a smaller proportion of the stellar populations in haloes containing a GSE analogue, and are stripped from satellites with stellar masses typically $\sim4$ times smaller. Our findings suggest that the higher spin of DM haloes without a GSE-like feature is due to mergers with large satellites of stellar mass $\sim10^{10}M_\odot$, which do not result in prominent radially anisotropic features like the GSE.
description: 6 pages, 5 figures, accepted for publication by MNRAS Letters
The Small Separation A-Star Companion Population: First Results with CHARA/MIRC-X
Creators: name: De Furio, Matthew
name: Gardner, Tyler
name: Monnier, John
name: Meyer, Michael R.
name: Kratter, Kaitlin
name: Schaefer, Gail
name: Anugu, Narsireddy
name: Davies, Claire L.
name: Kraus, Stefan
name: Lanthermann, Cyprien
name: Bouquin, Jean-Baptiste Le
name: Ennis, Jacob
Publisher: name: arXiv
Year: 2022
Subjects: subject: Solar and Stellar Astrophysics (astro-ph.SR)
subject: FOS: Physical sciences

description: We present preliminary results from our long-baseline interferometry (LBI) survey to constrain the multiplicity properties of intermediate-mass A-type stars within 80pc. Previous multiplicity studies of nearby stars exhibit orbital separation distributions well-fitted with a log-normal with peaks > 15au, increasing with primary mass. The A-star multiplicity survey of De Rosa et al. (2014), sensitive beyond 30au but incomplete below 100 au, found a log-normal peak around 390au. Radial velocity surveys of slowly-rotating, chemically peculiar Am stars identified a significant number of very close companions with periods $\leq$ 5 days, ~ 0.1au, a result similar to surveys of O- and B-type primaries. With the improved performance of LBI techniques, we can probe these close separations for normal A-type stars where other surveys are incomplete. Our initial sample consists of 27 A-type primaries with estimated masses between 1.44-2.49M$_{\odot}$ and ages 10-790Myr, which we observed with the MIRC-X instrument at the CHARA Array. We use the open source software CANDID to detect five companions, three of which are new, and derive a companion frequency of 0.19$^{+0.11}_{-0.06}$ over mass ratios 0.25-1.0 and projected separations 0.288-5.481 au. We find a probability of 10$^{-6}$ that our results are consistent with extrapolations based on previous models of the A-star companion population, over mass ratios and separations sampled. Our results show the need to explore these very close separations to inform our understanding of stellar formation and evolution processes.
description: 14 pages, 3 figures, Accepted to the Astrophysical Journal on Nov. 2, 2022
Black holes in multi-fractional and Lorentz-violating models
Creators: name: Calcagni, Gianluca
name: Fernández, David Rodríguez
name: Ronco, Michele
Publisher: name: arXiv
Year: 2017
Subjects: subject: General Relativity and Quantum Cosmology (gr-qc)
subject: High Energy Physics - Theory (hep-th)
subject: FOS: Physical sciences

description: We study static and radially symmetric black holes in the multi-fractional theories of gravity with $q$-derivatives and with weighted derivatives, frameworks where the spacetime dimension varies with the probed scale and geometry is characterized by at least one fundamental length $\ell_*$. In the $q$-derivatives scenario, one finds a tiny shift of the event horizon. Schwarzschild black holes can present an additional ring singularity, not present in general relativity, whose radius is proportional to $\ell_*$. In the multi-fractional theory with weighted derivatives, there is no such deformation, but non-trivial geometric features generate a cosmological-constant term, leading to a de Sitter--Schwarzschild black hole. For both scenarios, we compute the Hawking temperature and comment on the resulting black hole thermodynamics. In the case with $q$-derivatives, black holes can be hotter than usual and possess an additional ring singularity, while in the case with weighted derivatives they have a de Sitter hair of purely geometric origin, which may lead to a solution of the cosmological constant problem similar to that in unimodular gravity. Finally, we compare our findings with other Lorentz-violating models.
description: 17 pages, 3 figures. v2: minor typos corrected, references added
A Hybrid-Monte-Carlo study of monolayer graphene with partially screened Coulomb interactions at finite spin density
Creators: name: Körner, Michael
name: Smith, Dominik
name: Buividovich, Pavel
name: Ulybyshev, Maksim
name: von Smekal, Lorenz
Publisher: name: arXiv
Year: 2017
Subjects: subject: Strongly Correlated Electrons (cond-mat.str-el)
subject: High Energy Physics - Lattice (hep-lat)
subject: FOS: Physical sciences

description: We report on Hybrid-Monte-Carlo simulations at finite spin density of the $π$-band electrons in monolayer graphene with realistic inter-electron interactions. Unlike simulations at finite charge-carrier density, these are not affected by a fermion-sign problem. Our results are in qualitative agreement with an interaction-induced warping of the Fermi contours, and a reduction of the bandwidth as observed in angle resolved photoemission spectroscopy experiments on charge-doped graphene systems. Furthermore, we find evidence that the neck-disrupting Lifshitz transition, which occurs when the Fermi level traverses the van Hove singularity (VHS), becomes a true quantum phase transition due to interactions. This is in-line with an instability of the VHS towards the formation of electronic ordered phases, which has been predicted by a variety of different theoretical approaches.
description: 19 pages, 22 figures, revised version accepted for publication (two additional figures and pages, reference list updated)
Properties and Patterns of Polarized Gravitational Waves
Creators: name: Mashhoon, Bahram
name: Rahvar, Sohrab
Publisher: name: arXiv
Year: 2022
Subjects: subject: General Relativity and Quantum Cosmology (gr-qc)
subject: FOS: Physical sciences

description: We discuss polarization of gravitational radiation within the standard framework of linearized general relativity. The recent experimental discovery of gravitational waves provides the impetus to revisit the implications of the spin-rotation-gravity coupling for polarized gravitational radiation; therefore, we consider the coupling of helicity of gravitational waves to the rotation of an observer or the gravitomagnetic field of a rotating astronomical source. Observational possibilities regarding polarization-dependent effects in connection with future gravitational wave detectors are briefly explored.
description: 22 pages; v2: presentation improved, references added, invited contribution to appear in Universe; v3: minor improvements
Grain Growth in the Dust Ring with Crescent around Very Low Mass Star ZZ Tau IRS with JVLA
Creators: name: Hashimoto, Jun
name: Liu, Hauyu Baobab
name: Dong, Ruobing
name: Liu, Beibei
name: Muto, Takayuki
Publisher: name: arXiv
Year: 2022
Subjects: subject: Earth and Planetary Astrophysics (astro-ph.EP)
subject: Solar and Stellar Astrophysics (astro-ph.SR)
subject: FOS: Physical sciences

description: The azimuthal asymmetries of dust rings in protoplanetary disks such as a crescent around young stars are often interpreted as dust traps, and thus as ideal locations for planetesimal and planet formations. Whether such dust traps effectively promote planetesimal formation in disks around very-low-mass stars (VLM; a mass of $\lesssim$0.2~$M_\odot$) is debatable, as the dynamical and grain growth timescales in such systems are long. To investigate grain growth in such systems, we studied the dust ring with crescent around the VLM star ZZ~Tau~IRS using the Karl G. Jansky Very Large Array (JVLA) at centimeter wavelengths. Significant signals were detected around ZZ~Tau~IRS. To estimate the maximum grain size ($a_{\rm max}$) in the crescent, we compared the observed spectral energy distribution (SED) with SEDs for various $a_{\rm max}$ values predicted by radiative transfer calculations. We found $a_{\rm max} \gtrsim$~1~mm and $\lesssim$~60~$μ$m in the crescent and ring, respectively, though our modeling efforts rely on uncertain dust properties. Our results suggest that grain growth occurred in the ZZ~Tau~IRS disk, relative to sub-micron-sized interstellar medium. Planet formation in crescent with mm-sized pebbles might proceed more efficiently than in other regions with sub-millimeter-sized pebbles via pebble accretion scenarios.
description: 11 pages, 3 figures, accepted in ApJ
Gravitational wave sources: reflections and echoes
Creators: name: Price, Richard
name: Khanna, Gaurav
Publisher: name: arXiv
Year: 2017
Subjects: subject: General Relativity and Quantum Cosmology (gr-qc)
subject: High Energy Astrophysical Phenomena (astro-ph.HE)
subject: FOS: Physical sciences

description: The recent detection of gravitational waves has generated interest in alternatives to the black hole interpretation of sources. One set of such alternatives involves a prediction of gravitational wave "echoes". We consider two aspects of possible echoes: First, general features of echoes coming from spacetime reflecting conditions. We find that the detailed nature of such echoes does not bear any clear relationship to quasi-normal frequencies. Second, we point out the pitfalls in the analysis of local reflecting "walls" near the horizon of rapidly rotating black holes.
description: 8 pages, 4 figures; to appear in Classical & Quantum Gravity (CQG)
A generalized Hilbert operator acting on conformally invariant spaces
Creators: name: Girela, Daniel
name: Merchán, Noel
Publisher: name: arXiv
Year: 2016
Subjects: subject: Complex Variables (math.CV)
subject: FOS: Mathematics
subject: 47B35, 30H10

description: If $μ$ is a positive Borel measure on the interval $[0, 1)$ we let $\mathcal H_μ$ be the Hankel matrix $\mathcal H_μ=(μ_{n, k})_{n,k\ge 0}$ with entries $μ_{n, k}=μ_{n+k}$, where, for $n\,=\,0, 1, 2, \dots $, $μ_n$ denotes the moment of orden $n$ of $μ$. This matrix induces formally the operator $$\mathcal{H}_μ(f)(z)= \sum_{n=0}^{\infty}\left(\sum_{k=0}^{\infty} μ_{n,k}{a_k}\right)z^n$$ on the space of all analytic functions $f(z)=\sum_{k=0}^\infty a_kz^k$, in the unit disc $\D $. This is a natural generalization of the classical Hilbert operator. The action of the operators $H_{μ}$ on Hardy spaces has been recently studied. This paper is devoted to study the operators $H_μ$ acting on certain conformally invariant spaces of analytic functions on the disc such as the Bloch space, $BMOA$, the analytic Besov spaces, and the $Q_s$ spaces.
description: 24 pages
Stochastic resetting in a networked multiparticle system with correlated transitions
Creators: name: Artime, Oriol
Publisher: name: arXiv
Year: 2022
Subjects: subject: Statistical Mechanics (cond-mat.stat-mech)
subject: FOS: Physical sciences

description: The state of many physical, biological and socio-technical systems evolves by combining smooth local transitions and abrupt resetting events to a set of reference values. The inclusion of the resetting mechanism not only provides the possibility of modeling a wide variety of realistic systems but also leads to interesting novel phenomenology not present in reset-free cases. However, most models where stochastic resetting is studied address the case of a finite number of uncorrelated variables, commonly a single one, such as the position of non-interacting random walkers. Here we overcome this limitation by framing the process of network growth with node deletion as a stochastic resetting problem where an arbitrarily large number of degrees of freedom are coupled and influence each other, both in the resetting and non-resetting (growth) events. We find the exact, full-time solution of the model, and several out-of-equilibrium properties are characterized as function of the growth and resetting rates, such as the emergence of a time-dependent percolation-like phase transition, and first-passage statistics. Coupled multiparticle systems subjected to resetting are a necessary generalization in the theory of stochastic resetting, and the model presented herein serves as an illustrative, natural and solvable example of such a generalization.
description: 14 pages, 4 figures
Synchronization of an optomechanical system to an external drive
Creators: name: Amitai, Ehud
name: Lörch, Niels
name: Nunnenkamp, Andreas
name: Walter, Stefan
name: Bruder, Christoph
Publisher: name: arXiv
Year: 2017
Subjects: subject: Quantum Physics (quant-ph)
subject: Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
subject: FOS: Physical sciences

description: Optomechanical systems driven by an effective blue detuned laser can exhibit self-sustained oscillations of the mechanical oscillator. These self-oscillations are a prerequisite for the observation of synchronization. Here, we study the synchronization of the mechanical oscillations to an external reference drive. We study two cases of reference drives: (1) An additional laser applied to the optical cavity; (2) A mechanical drive applied directly to the mechanical oscillator. Starting from a master equation description, we derive a microscopic Adler equation for both cases, valid in the classical regime in which the quantum shot noise of the mechanical self-oscillator does not play a role. Furthermore, we numerically show that, in both cases, synchronization arises also in the quantum regime. The optomechanical system is therefore a good candidate for the study of quantum synchronization.
description: 9 pages, 6 figures
Vertical stratification of forest canopy for segmentation of under-story trees within small-footprint airborne LiDAR point clouds
Creators: name: Hamraz, Hamid
name: Contreras, Marco A.
name: Zhang, Jun
Publisher: name: arXiv
Year: 2017
Subjects: subject: Computer Vision and Pattern Recognition (cs.CV)
subject: Computational Engineering, Finance, and Science (cs.CE)
subject: Computational Geometry (cs.CG)
subject: FOS: Computer and information sciences

description: Airborne LiDAR point cloud representing a forest contains 3D data, from which vertical stand structure even of understory layers can be derived. This paper presents a tree segmentation approach for multi-story stands that stratifies the point cloud to canopy layers and segments individual tree crowns within each layer using a digital surface model based tree segmentation method. The novelty of the approach is the stratification procedure that separates the point cloud to an overstory and multiple understory tree canopy layers by analyzing vertical distributions of LiDAR points within overlapping locales. The procedure does not make a priori assumptions about the shape and size of the tree crowns and can, independent of the tree segmentation method, be utilized to vertically stratify tree crowns of forest canopies. We applied the proposed approach to the University of Kentucky Robinson Forest - a natural deciduous forest with complex and highly variable terrain and vegetation structure. The segmentation results showed that using the stratification procedure strongly improved detecting understory trees (from 46% to 68%) at the cost of introducing a fair number of over-segmented understory trees (increased from 1% to 16%), while barely affecting the overall segmentation quality of overstory trees. Results of vertical stratification of the canopy showed that the point density of understory canopy layers were suboptimal for performing a reasonable tree segmentation, suggesting that acquiring denser LiDAR point clouds would allow more improvements in segmenting understory trees. As shown by inspecting correlations of the results with forest structure, the segmentation approach is applicable to a variety of forest types.
Performance of different correction maps in the extended phase-space method for spinning compact binaries
Creators: name: Luo, Junjie
name: Feng, Jie
name: Zhang, Hong-Hao
name: Lin, Weipeng
Publisher: name: arXiv
Year: 2022
Subjects: subject: General Relativity and Quantum Cosmology (gr-qc)
subject: Instrumentation and Methods for Astrophysics (astro-ph.IM)
subject: FOS: Physical sciences

description: Since the first detection of gravitational waves by the LIGO/VIRGO team, the related research field has attracted more attention. The spinning compact binaries system, as one of the gravitational-wave sources for broadband laser interferometers, has been widely studied by related researchers. In order to analyze the gravitational wave signals using matched filtering techniques, reliable numerical algorithms are needed. Spinning compact binaries systems in Post-Newtonian (PN) celestial mechanics have an inseparable Hamiltonian. The extended phase-space algorithm is an effective solution for the problem of this system. We have developed correction maps for the extended phase-space method in our previous work, which significantly improves the accuracy and stability of the method with only a momentum scale factor. In this paper, we will add more scale factors to modify the numerical solution in order to minimize the errors in the constants of motion. However, we find that these correction maps will result in a large energy bias in the subterms of the Hamiltonian in chaotic orbits, whose potential and kinetic energy, etc. are calculated inaccurately. We develop new correction maps to reduce the energy bias of the subterms of the Hamiltonian, which can instead improve the accuracy of the numerical solution and also provides a new idea for the application of the manifold correction in other algorithms.
Charge-density-wave order takes over antiferromagnetism in Bi$_2$Sr$_{2-x}$La$_x$CuO$_{6}$ superconductors
Creators: name: Kawasaki, S.
name: Li, Z.
name: Kitahashi, M.
name: Lin, C. T.
name: Kuhns, P. L.
name: Reyes, A. P.
name: Zheng, Guo-qing
Publisher: name: arXiv
Year: 2017
Subjects: subject: Superconductivity (cond-mat.supr-con)
subject: FOS: Physical sciences

description: Superconductivity appears in the cuprates when a spin order is destroyed, while the role of charge is less known. Recently, charge density wave (CDW) was found below the superconducting dome in YBa$_2$Cu$_3$O$_y$ when a high magnetic field is applied perpendicular to the CuO$_2$ plane, which was suggested to arise from incipient CDW in the vortex cores that becomes overlapped. Here, by $^{63}$Cu-nuclear magnetic resonance, we report the discovery of CDW induced by an in-plane field that does not create vortex cores in the plane, setting in above the dome in single-layered Bi$_2$Sr$_{2-x}$La$_x$CuO$_6$.The onset temperature $T_{\rm CDW}$ takes over the antiferromagnetic order temperature $T_{\rm N}$ beyond a critical doping level at which superconductivity starts to emerge, and scales with the psudogap temperature $T^{*}$. These results provide important insights into the relationship between spin order, CDW and the pseudogap, and their connections to high-temperature superconductivity.
description: 22 pages, 8 figures
Proton Synchrotron, an explanation for possible extended VHE gamma-ray activity of TXS 0506+056 in 2017
Creators: name: Sunanda
name: Moharana, Reetanjali
name: Majumdar, Pratik
Publisher: name: arXiv
Year: 2022
Subjects: subject: High Energy Astrophysical Phenomena (astro-ph.HE)
subject: High Energy Physics - Phenomenology (hep-ph)
subject: FOS: Physical sciences

description: TXS 0506+056, a source of the extreme energy neutrino event, IceCube-170922A, was observed on 22 September 2017. The Fermi-LAT detector reported high energy (HE) $γ$-ray flare between 100 MeV and 100 GeV starting from 15 September 2017 from this source. Several attempts to trace the very high energy (VHE) gamma-ray counterparts around the IceCube-170922A resulted in no success. Only after 28 September, the Major Atmospheric Gamma-ray Imaging Cherenkov (MAGIC) telescopes observed the first VHE gamma-rays from the blazar above 100 GeV. The $\sim$ 41 hr survey resulted in VHE-$γ$ ray activity till 31 October 2017. Here we propose the extended GeV $γ-$rays can be explained by taking two production channels, electron synchrotron self Compton and proton synchrotron for HE and VHE emissions, respectively. The 45 days of VHE emission from the peak of the HE-flare can be explained with $ {L_p'}{\simeq}10^{47}$ erg/sec in the jet frame and magnetic field of 2.4 G, consistent with the ${L}_{Edd}$ for a blackhole mass $5\times 10^{9} {M}_\odot$
Volatility Prediction using Financial Disclosures Sentiments with Word Embedding-based IR Models
Creators: name: Rekabsaz, Navid
name: Lupu, Mihai
name: Baklanov, Artem
name: Hanbury, Allan
name: Duer, Alexander
name: Anderson, Linda
Publisher: name: arXiv
Year: 2017
Subjects: subject: Information Retrieval (cs.IR)
subject: Computational Engineering, Finance, and Science (cs.CE)
subject: FOS: Computer and information sciences

description: Volatility prediction--an essential concept in financial markets--has recently been addressed using sentiment analysis methods. We investigate the sentiment of annual disclosures of companies in stock markets to forecast volatility. We specifically explore the use of recent Information Retrieval (IR) term weighting models that are effectively extended by related terms using word embeddings. In parallel to textual information, factual market data have been widely used as the mainstream approach to forecast market risk. We therefore study different fusion methods to combine text and market data resources. Our word embedding-based approach significantly outperforms state-of-the-art methods. In addition, we investigate the characteristics of the reports of the companies in different financial sectors.
HD 20329b: An ultra-short-period planet around a solar-type star found by TESS
Creators: name: Murgas, F.
name: Nowak, G.
name: Masseron, T.
name: Parviainen, H.
name: Luque, R.
name: Pallé, E.
name: Korth, Judith
name: Carleo, I.
name: Csizmadia, Sz.
name: Esparza-Borges, E.
name: Alqasim, Ahlam
name: Cochran, William D.
name: Dai, Fei
name: Deeg, Hans J.
name: Gandolfi, D.
name: Goffo, Elisa
name: Kabáth, Petr
name: Lam, K. W. F.
name: Livingston, John
name: Muresan, Alexandra
name: Osborne, H. L. M.
name: Persson, Carina M.
name: Serrano, L. M.
name: Smith, Alexis M. S.
name: Van Eylen, Vincent
name: Orell-Miquel, J.
name: Hinkel, Natalie R.
name: Galán, D.
name: Puig-Subirà, M.
name: Stangret, M.
name: Fukui, A.
name: Kagetani, T.
name: Narita, N.
name: Ciardi, David R.
name: Boyle, Andrew W.
name: Ziegler, Carl
name: Briceño, César
name: Law, Nicholas
name: Mann, Andrew W.
name: Jenkins, Jon M.
name: Latham, David W.
name: Quinn, Samuel N.
name: Ricker, G.
name: Seager, S.
name: Shporer, Avi
name: Ting, Eric B.
name: Vanderspek, R.
name: Winn, Joshua N.
Publisher: name: arXiv
Year: 2022
Subjects: subject: Earth and Planetary Astrophysics (astro-ph.EP)
subject: Solar and Stellar Astrophysics (astro-ph.SR)
subject: FOS: Physical sciences

description: We used TESS light curves and HARPS-N spectrograph radial velocity measurements to establish the physical properties of the transiting exoplanet candidate found around the star HD 20329 (TOI-4524). We performed a joint fit of the light curves and radial velocity time series to measure the mass, radius, and orbital parameters of the candidate. We confirm and characterize HD 20329b, an ultra-short-period (USP) planet transiting a solar-type star. The host star (HD 20329, $V = 8.74$ mag, $J = 7.5$ mag) is characterized by its G5 spectral type with $\mathrm{M}_\star= 0.90 \pm 0.05$ M$_\odot$, $\mathrm{R}_\star = 1.13 \pm 0.02$ R$_\odot$, and $\mathrm{T}_{\mathrm{eff}} = 5596 \pm 50$ K; it is located at a distance $d= 63.68 \pm 0.29$ pc. By jointly fitting the available TESS transit light curves and follow-up radial velocity measurements, we find an orbital period of $0.9261 \pm (0.5\times 10^{-4})$ days, a planetary radius of $1.72 \pm 0.07$ $\mathrm{R}_\oplus$, and a mass of $7.42 \pm 1.09$ $\mathrm{M}_\oplus$, implying a mean density of $ρ_\mathrm{p} = 8.06 \pm 1.53$ g cm$^{-3}$. HD 20329b joins the $\sim$30 currently known USP planets with radius and Doppler mass measurements.
description: Accepted for publication in A&A, 26 pages
Discovery of a double sequence of blue straggler stars in the core-collapsed globular cluster NGC 6256
Creators: name: Cadelano, Mario
name: Ferraro, Francesco R.
name: Dalessandro, Emanuele
name: Lanzoni, Barbara
name: Pallanca, Cristina
name: Saracino, Sara
Publisher: name: arXiv
Year: 2022
Subjects: subject: Solar and Stellar Astrophysics (astro-ph.SR)
subject: Astrophysics of Galaxies (astro-ph.GA)
subject: FOS: Physical sciences

description: We used a combination of high-resolution optical images acquired with the Hubble Space Telescope and near-IR wide-field data to investigate the stellar density profile and the population of blue straggler star (BSS) in the Galactic globular cluster NGC6256, with the aim of probing its current stage of internal dynamical evolution. We found that the inner stellar density profile significantly deviates from a King model while is well reproduced by a steep cusp with a power-law slope alpha=-0.89, thus implying that the cluster is currently in the post core-collapse (PCC) phase. This is also confirmed by the very high segregation level of the BSS population measured through the A+ parameter. We also found that the distribution of BSSs in the color-magnitude diagram is characterized by a collimated blue sequence and a red more sparse component, as already observed in other three PCC clusters. The comparison with appropriate collisional models demonstrates that the vast majority of the BSSs lying along the collimated blue sequence is consistent with a generation of coeval (1 Gyr-old) stars with different masses originated by an event that highly enhanced the collisional rate of the system (i.e. the core collapse). This study confirms that the segregation level of BSSs is a powerful dynamical diagnostic also of star cluster in a very advanced stage of dynamical evolution. Moreover, it pushes forward the possibility of using the morphology of the BSS in the color-magnitude diagram as a tracer of the core-collapse and subsequent dynamical evolutionary phases.
description: Accepted for publication in ApJ
Unusual Abundances from Planetary System Material Polluting the White Dwarf G238-44
Creators: name: Johnson, Ted M
name: Klein, Beth L.
name: Koester, D.
name: Melis, Carl
name: Zuckerman, B.
name: Jura, M.
Publisher: name: arXiv
Year: 2022
Subjects: subject: Earth and Planetary Astrophysics (astro-ph.EP)
subject: Solar and Stellar Astrophysics (astro-ph.SR)
subject: FOS: Physical sciences

description: Ultraviolet and optical spectra of the hydrogen-dominated atmosphere white dwarf star G238-44 obtained with FUSE, Keck/HIRES, HST/COS, and HST/STIS reveal ten elements heavier than helium: C, N, O, Mg, Al, Si, P, S, Ca, and Fe. G238-44 is only the third white dwarf with nitrogen detected in its atmosphere from polluting planetary system material. Keck/HIRES data taken on eleven nights over 24 years show no evidence for variation in the equivalent width of measured absorption lines, suggesting stable and continuous accretion from a circumstellar reservoir. From measured abundances and limits on other elements we find an anomalous abundance pattern and evidence for the presence of metallic iron. If the pollution is from a single parent body, then it would have no known counterpart within the solar system. If we allow for two distinct parent bodies, then we can reproduce the observed abundances with a mix of iron-rich Mercury-like material and an analog of an icy Kuiper Belt object with a respective mass ratio of 1.7:1. Such compositionally disparate objects would provide chemical evidence for both rocky and icy bodies in an exoplanetary system and would be indicative of a planetary system so strongly perturbed that G238-44 is able to capture both asteroid- and Kuiper Belt-analog bodies near-simultaneously within its $<$100 Myr cooling age.
description: Accepted to ApJ. 18 pages, 9 figures, 7 tables
Self-Similar solution of rotating eruptive outflows on its equatorial plane
Creators: name: Ko, Takatoshi
name: Fujisawa, Kotaro
name: Shigeyama, Toshikazu
Publisher: name: arXiv
Year: 2022
Subjects: subject: High Energy Astrophysical Phenomena (astro-ph.HE)
subject: FOS: Physical sciences
subject: 85-10

description: We construct axisymmetric self-similar solutions of transonic outflows emanating from a point source including the effect of the rotation. The solutions are constructed exclusively on the equatorial plane. The features of solutions are determined by three parameters; the adiabatic index $γ$, the dimensionless coordinate of the transonic point, and the dimensionless azimuthal velocity at the transonic point. We classify the solutions into five groups according to the asymptotic behaviors. We find that the behaviors of the self-similar solutions change at $γ= 11/9$. In addition, some solutions show double-power-law density profiles, which are usually seen in ejecta from a binary merger or nova-like explosion. Thus, our self-similar solutions can be applied not only to the outflow blowing from the central spinning objects, but also to the ejecta erupted from the binary merger or nova-like explosion.
description: 14 pages, 6 figures, 1 table. Accepted by ApJ
Contextuality and Informational Redundancy
Creators: name: Dzhafarov, Ehtibar N.
name: Kujala, Janne V.
Publisher: name: arXiv
Year: 2022
Subjects: subject: Quantum Physics (quant-ph)
subject: Probability (math.PR)
subject: FOS: Physical sciences
subject: FOS: Mathematics
subject: 81P13, 81Q99, 60A99

description: A noncontextual system of random variables may become contextual if one adds to it a set of new variables, even if each of them is obtained by the same context-wise function of the old variables. This fact follows from the definition of contextuality, and its demonstration is trivial for inconsistently connected systems (i.e. systems with disturbance). However, it also holds for consistently connected (and even strongly consistently connected) systems, provided one acknowledges that if a given property was not measured in a given context, this information can be used in defining functions among the random variables. Moreover, every inconsistently connected system can be presented as a (strongly) consistently connected system with essentially the same contextuality characteristics.
description: 13 pp
Junction Conditions for F(T) Gravity from a Variational Principle
Creators: name: Velay-Vitow, Jesse
name: DeBenedictis, Andrew
Publisher: name: arXiv
Year: 2017
Subjects: subject: General Relativity and Quantum Cosmology (gr-qc)
subject: FOS: Physical sciences
subject: 58J32, 49S99

description: We derive a general set of acceptable junction conditions for $F(T)$ gravity via the variational principle. The analysis is valid for both the traditional form of $F(T)$ gravity theory as well as the more recently introduced Lorentz covariant theory of Krššák and Saridakis. We find that the general junction conditions derived, when applied to simple cases such as highly symmetric static or time dependent geometries (such as spherical symmetry) imply both the Synge junction conditions as well as the Israel-Sen-Lanczos-Darmois junction conditions of General Relativity. In more complicated scenarios the junction conditions derived do not generally imply the well-known junction conditions of General Relativity. However, the junctions conditions of de la Cruz-Dombriz, Dunsby, and Sáez-Gómez make up an interesting subset of this more general case.
description: 14 pages, 1 figure. Updated version contains clarification on the role of the spin connection and a number of added references. Matches version accepted for publication in Phys. Rev. D
Extended Kitaev chain with longer-range hopping and pairing
Creators: name: Alecce, Antonio
name: Dell'Anna, Luca
Publisher: name: arXiv
Year: 2017
Subjects: subject: Strongly Correlated Electrons (cond-mat.str-el)
subject: Statistical Mechanics (cond-mat.stat-mech)
subject: Superconductivity (cond-mat.supr-con)
subject: FOS: Physical sciences

description: We consider the Kitaev chain model with finite and infinite range in the hopping and pairing parameters, looking in particular at the appearance of Majorana zero energy modes and massive edge modes. We study the system both in the presence and in the absence of time reversal symmetry, by means of topological invariants and exact diagonalization, disclosing very rich phase diagrams. In particular, for extended hopping and pairing terms, we can get as many Majorana modes at each end of the chain as the neighbors involved in the couplings. Finally we generalize the transfer matrix approach useful to calculate the zero-energy Majorana modes at the edges for a generic number of coupled neighbors.
description: 14 pages, 16 figures
One-Dimensional Numerical Study on Ignition of the Helium Envelope in Dynamical Accretion during the Double-Degenerate Merger
Creators: name: Iwata, Kazuya
name: Maeda, Keiichi
Publisher: name: arXiv
Year: 2022
Subjects: subject: High Energy Astrophysical Phenomena (astro-ph.HE)
subject: Solar and Stellar Astrophysics (astro-ph.SR)
subject: FOS: Physical sciences

description: In order for a double-detonation model to be viable for normal type Ia supernovae, the adverse impact of helium-burning ash on early-time observables has to be avoided, which requires that the helium envelope mass should be at most 0.02 solar mass. Most of the previous studies introduced detonation by artificial hot spots, and therefore the robustness of the spontaneous helium detonation remains uncertain. In the present work, we conduct a self-consistent hydrodynamic study on the spontaneous ignition of the helium envelope in the context of the double-degenerate channel, by applying an idealized one-dimensional model and a simplified 7 isotope reaction network. We explore a wide range of the progenitor conditions, and demonstrate that the chance of direct initiation of detonation is limited. Especially, the spontaneous detonation requires the primary envelope mass of >~ 0.03 solar mass. Ignition as deflagration is instead far more likely, which is feasible for the lower envelope mass down to ~ 0.01 solar mass, which might lead to subsequent detonation once the deflagration to detonation transition (DDT) would be realized. High-resolution multi-dimensional simulations are required to further investigate the DDT possibility, as well as accurately derive the threshold between the spontaneous detonation and deflagration ignition regimes. Another interesting finding is the effect of the composition; while mixing with the core material enhances detonation as previously suggested, it rather narrows the chance for deflagration due to the slower rate of 12C(alpha,gamma)16O reaction at the lower temperature ~108K, with the caveat that we presently neglect the proton-catalyzed reaction sequence of 12C(p,gamma)13O(alpha,p)16O.
description: accepted for publication in ApJ
Exact logarithmic four-point functions in the critical two-dimensional Ising model
Creators: name: Gori, Giacomo
name: Viti, Jacopo
Publisher: name: arXiv
Year: 2017
Subjects: subject: Statistical Mechanics (cond-mat.stat-mech)
subject: Strongly Correlated Electrons (cond-mat.str-el)
subject: High Energy Physics - Theory (hep-th)
subject: Mathematical Physics (math-ph)
subject: FOS: Physical sciences

description: Based on conformal symmetry we propose an exact formula for the four-point connectivities of FK clusters in the critical Ising model when the four points are anchored to the boundary. The explicit solution we found displays logarithmic singularities. We check our prediction using Monte Carlo simulations on a triangular lattice, showing excellent agreement. Our findings could shed further light on the formidable task of the characterization of Logarithmic Conformal Field Theories and on their relevance in physics.
description: 5+3 pages, 4 Figures, published version, minor revisions and references added
Analysis of the arm-like structure in the outer disk of PDS 70. Spiral density wave or vortex?
Creators: name: Juillard, S.
name: Christiaens, V.
name: Absil, O.
Publisher: name: arXiv
Year: 2022
Subjects: subject: Earth and Planetary Astrophysics (astro-ph.EP)
subject: Instrumentation and Methods for Astrophysics (astro-ph.IM)
subject: FOS: Physical sciences

description: Observing dynamical interactions between planets and disks is key to understanding their formation and evolution. Two protoplanets have recently been discovered within PDS 70's protoplanetary disk, along with an arm-like structure towards the north-west of the star. Our aim is to constrain the morphology and origin of this arm-like structure, and to assess whether it could trace a spiral density wave caused by the dynamical interaction between the planet PDS 70c and the disk. We analyze polarized and angular differential imaging (PDI and ADI) data taken with VLT/SPHERE, spanning six years of observations. PDI data sets are reduced using the IRDAP polarimetric data reduction pipeline, while ADI data sets are processed using MUSTARD, a novel inverse problem algorithm to tackle the geometrical biases spoiling the images previously used for the analysis of this disk. We confirm the presence of the arm-like structure in all PDI and ADI datasets. We do not observe a south-east symmetric arm with respect to the disk minor axis, which seems to disfavor the previous hypothesis that the arm is the footprint of a double-ring structure. If the structure traces a spiral density wave following the motion of PDS 70c, we would expect $11\overset{\circ}{.}28^{+2\overset{\circ}{.}20}_{-0\overset{\circ}{.}86}$ rotation for the spiral in six years. However, we do not measure any significant movement of the structure. If the arm-like structure is a planet-driven spiral arm, the observed lack of rotation would suggest that the assumption of rigid-body rotation may be inappropriate for spirals induced by planets. We suggest that the arm-like structure may rather trace a vortex appearing as a one-armed spiral in scattered light due to projection effects. The vortex hypothesis accounts for both the lack of observed rotation and the presence of a nearby sub-mm continuum asymmetry detected with ALMA.
description: Accepted for publication in Astronomy&Astrophysics. 11 pages, 10 figures
Damped spin-wave excitations in the itinerant antiferromagnet $γ$-Fe$_{0.7}$Mn$_{0.3}$
Creators: name: Ibuka, S.
name: Itoh, S.
name: Yokoo, T.
name: Endoh, Y.
Publisher: name: arXiv
Year: 2016
Subjects: subject: Materials Science (cond-mat.mtrl-sci)
subject: Strongly Correlated Electrons (cond-mat.str-el)
subject: FOS: Physical sciences

description: The collective spin-wave excitations in the antiferromagnetic state of $γ$-Fe$_{0.7}$Mn$_{0.3}$ were investigated using the inelastic neutron scattering technique. The spin excitations remain isotropic up to the high excitation energy, ${\hbarω}= 78$ meV. The excitations gradually become broad and damped above 40 meV. The damping parameter $γ$ reaches 110(16) meV at ${\hbarω} = 78$ meV, which is much larger than that for other metallic compounds, e.g., CaFe$_2$As$_2$ (24 meV), La$_{2-2x}$Sr$_{1+2x}$Mn$_2$O$_7$ ($52-72$ meV), and Mn$_{90}$Cu$_{10}$ (88 meV). In addition, the spin-wave dispersion shows a deviation from the relation $({\hbarω})^2 = c^2q^2 + Δ^2$ above 40 meV. The group velocity above this energy increases to 470(40) meVÅ, which is higher than that at the low energies, $c = 226(5)$ meVÅ. These results could suggest that the spin-wave excitations merge with the continuum of the individual particle-hole excitations at 40 meV.
description: 7 pages, 6 figures
Mott Transition and Magnetism in Rare Earth Nickelates and its Fingerprint on the X-ray Scattering
Creators: name: Haule, Kristjan
name: Pascut, Gheorghe L.
Publisher: name: arXiv
Year: 2017
Subjects: subject: Strongly Correlated Electrons (cond-mat.str-el)
subject: FOS: Physical sciences

description: The metal-insulator transition (MIT) remains among the most thoroughly studied phenomena in solid state physics, but the complexity of the phenomena, which usually involves cooperation of many degrees of freedom including orbitals, fluctuating local moments, magnetism, and the crystal structure, have resisted predictive ab-initio treatment. Here we develop ab-initio theoretical method for correlated electron materials, based on Dynamical Mean Field Theory, which can predict the change of the crystal structure across the MIT at finite temperature. This allows us to study the coupling between electronic, magnetic and orbital degrees of freedom with the crystal structure across the MIT in rare-earth nickelates. We predict the free energy profile of the competing states, and the theoretical magnetic ground state configuration, which is in agreement with neutron scattering data, but is different from the magnetic models proposed before. The resonant elastic X-ray response at the K-edge, which was argued to be a direct probe of the charge order, is theoretically modelled within the Dynamical Mean Field Theory, including the core-hole interaction. We show that the line-shape of the measured resonant elastic X-ray response can be explained with the "site-selective" Mott scenario without real charge order on Ni sites.
description: Acknowledgments updated, citations added
No snowball on habitable tidally locked planets
Creators: name: Checlair, Jade
name: Menou, Kristen
name: Abbot, Dorian S.
Publisher: name: arXiv
Year: 2017
Subjects: subject: Earth and Planetary Astrophysics (astro-ph.EP)
subject: FOS: Physical sciences

description: The TRAPPIST-1, Proxima Centauri, and LHS 1140 systems are the most exciting prospects for future follow-up observations of potentially inhabited planets. All orbit nearby M-stars and are likely tidally locked in 1:1 spin-orbit states, which motivates the consideration of the effects that tidal locking might have on planetary habitability. On Earth, periods of global glaciation (snowballs) may have been essential for habitability and remote signs of life (biosignatures) because they are correlated with increases in the complexity of life and in the atmospheric oxygen concentration. In this paper we investigate the snowball bifurcation (sudden onset of global glaciation) on tidally locked planets using both an energy balance model and an intermediate-complexity global climate model. We show that tidally locked planets are unlikely to exhibit a snowball bifurcation as a direct result of the spatial pattern of insolation they receive. Instead they will smoothly transition from partial to complete ice coverage and back. A major implication of this work is that tidally locked planets with an active carbon cycle should not be found in a snowball state. Moreover, this work implies that tidally locked planets near the outer edge of the habitable zone with low CO2 outgassing fluxes will equilibrate with a small unglaciated substellar region rather than cycling between warm and snowball states. More work is needed to determine how the lack of a snowball bifurcation might affect the development of life on a tidally locked planet.
description: Accepted at the Astrophysical Journal on 07/11/17
title: Two different parental melt trends for the Deccan Trap main sequence
Creators: name: Pakulla, Josua
name: Jansen, Mike
name: Duraiswami, Raymond A.
name: Gadpallu, Purva
name: Tusch, Jonas
name: Wombacher, Frank
name: Münker, Carsten
Publisher: name: Deutsche Geologische Gesellschaft - Geologische Vereinigung e.V. (DGGV)
Year: 2022

description:
The lava flows of the Deccan Large Igneous Province (DLIP) cover at least one million years of continuous magmatic activity across the Cretaceous-Paleogene boundary (Schoene et al. 2021) likely representing the initial stage of the Réunion plume. Earlier studies suggested that the geochemical signatures of basaltic rocks from the DLIP main sequence originated from melts of the depleted upper mantle and Réunion plume that mixed within magma chamber systems (e.g. Peng et al. 1994). In this scenario, the compositional range of the DLIP is best explained by subsequent assimilation of varying proportions of crustal and lithospheric components during ascent.The major and trace element as well as Sr-Nd-Hf-Pb isotope data of this study covers the entire stratigraphy of the DLIP main sequence and casts doubt on the generally accepted interpretation. Most notably, Pb isotopes as well as high field strength element systematics suggest two separate magma differentiation trends in the petrogenetic pathway of DLIP melts. The observed trends are best explained by two mafic endmembers that tap different mantle source reservoirs. Our isotope and trace element data suggests that melts from these reservoirs, namely the depleted upper mantle and lower mantle (Réunion plume) assimilated crustal and lithospheric components to a variable degree. Consequently, lava flows within single volcano-stratigraphic formations of the DLIP likely originated from different parental melts that did not interact during ascent. Previously, such fast-changing contributions from different mantle reservoirs have been underestimated for the Deccan volcanic rocks.

Peng et al. 1994. GCASchoene et al. 2021, GChron
An improved MHD simulation of the 2006 December 13 coronal mass ejection of active region NOAA 10930
Creators: name: Fan, Yuhong
Publisher: name: arXiv
Year: 2022
Subjects: subject: Solar and Stellar Astrophysics (astro-ph.SR)
subject: FOS: Physical sciences

description: We present a magnetohydrodynamic (MHD) simulation of the coronal mass ejection (CME) on 13 December 2006 in the emerging delta-sunspot active region 10930, improving upon a previous simulation by Fan (2016) as follows. (1) Incorporate an ambient solar wind instead of using a static potential magnetic field extrapolation as the initial state. (2) In addition to imposing the emergence of a twisted flux rope, also impose at the lower boundary a random electric field that represents the effect of turbulent convection, which drives field-line braiding and produces resistive and viscous heating in the corona. With the inclusion of this heating, which depends on the magnetic field topology, we are able to model the synthetic soft X-ray images that would be observed by the X-Ray Telescope (XRT) of the Hinode satellite, produced by the simulated coronal magnetic field. We find that the simulated pre-eruption magnetic field with the build up of a twisted magnetic flux rope, produces synthetic soft X-ray emission that shows qualitatively similar morphology as that observed by the Hinode/XRT for both the ambient coronal loops of the active region and the central inverse-S shaped "sigmoid" that sharpens just before the onset of the eruption. The synthetic post-flare loop brightening also shows similar morphology as that seen in the Hinode/XRT image during the impulsive phase of the eruption. It is found that the kinematics of the erupting flux rope is significantly affected by the open magnetic fields and fast solar wind streams adjacent to the active region.
description: 17 pages, 14 figures, accepted for publication in the Astrophysical Journal