arXiv - PHYS - Solar and Stellar Astrophysics最新文献

{"title":"Multi-wavelength spectroscopic analysis of the ULX Holmberg II","authors":"S. Reyero Serantes, L. Oskinova, W. -R. Hamann, V. M. Gómez-González, H. Todt, D. Pauli, R. Soria, D. R. Gies, J. M. Torrejón, T. Bulik, V. Ramachandran, A. A. C. Sander, E. Bozzo, J. Poutanen","doi":"arxiv-2409.12133","DOIUrl":"https://doi.org/arxiv-2409.12133","url":null,"abstract":"Ultra-luminous X-ray sources (ULXs) are high-mass X-ray binaries with an\u0000X-ray luminosity above $10^{39}$ erg s$^{-1}$. These ULXs can be powered by\u0000black holes that are more massive than $20M_odot$, accreting in a standard\u0000regime, or lighter compact objects accreting supercritically. There are only a\u0000few ULXs with known optical or UV counterparts, and their nature is debated.\u0000Determining whether optical/UV radiation is produced by the donor star or by\u0000the accretion disc is crucial for understanding ULX physics and testing massive\u0000binary evolution. We conduct, for the first time, a fully consistent\u0000multi-wavelength spectral analysis of a ULX and its circumstellar nebula. We\u0000aim to establish the donor star type and test the presence of strong disc winds\u0000in the prototypical ULX Holmberg II X-1 (Ho II X-1). We intent to obtain a\u0000realistic spectral energy distribution of the ionising source, which is needed\u0000for robust nebula analysis. We acquired new UV spectra of Ho II X-1 with the\u0000HST and complemented them with archival optical and X-ray data. We explored the\u0000spectral energy distribution of the source and analysed the spectra using the\u0000stellar atmosphere code PoWR and the photoionisation code Cloudy. Our analysis\u0000of the X-ray, UV, and optical spectra of Ho II X-1 and its nebula consistently\u0000explains the observations. We do not find traces of disc wind signatures in the\u0000UV and the optical, rejecting previous claims of the ULX being a supercritical\u0000accretor. The optical/UV counterpart of HoII X-1 is explained by a B-type\u0000supergiant donor star. Thus, the observations are fully compatible with Ho II\u0000X-1 being a close binary consisting of an $gtrsim 66,M_odot$ black hole\u0000accreting matter from an $simeq 22 M_odot$ B-supergiant companion. Also, we\u0000propose a possible evolution scenario for the system, suggesting that Ho II X-1\u0000is a potential gravitational wave source progenitor.","PeriodicalId":501068,"journal":{"name":"arXiv - PHYS - Solar and Stellar Astrophysics","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2024-09-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142257934","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Characterization of blue and yellow straggler stars of Berkeley 39 using Swift/UVOT","authors":"Komal Chand, Khushboo Rao, Kaushar Vaidya, Anju Panthi","doi":"arxiv-2409.12062","DOIUrl":"https://doi.org/arxiv-2409.12062","url":null,"abstract":"We characterize blue straggler stars (BSS) and yellow straggler stars (YSS)\u0000of an open cluster (OC) Berkeley 39 using multi-wavelength observations\u0000including Swift/UVOT. Our analysis also makes use of ultraviolet (UV) data from\u0000GALEX, optical data from Gaia DR3 and Pan-STARRS, and infrared data from 2MASS,\u0000Spitzer/IRAC, and WISE. Berkeley 39 is a ~6 Gyr old Galactic OC located at a\u0000distance of ~4200 pc. We identify 729 sources as cluster members utilizing a\u0000machine learning algorithm, ML-MOC, on Gaia DR3 data. Of these, 17 sources are\u0000classified as BSS candidates and four as YSS candidates. We construct\u0000multi-wavelength spectral energy distributions (SEDs) of 16 BSS and 2 YSS\u0000candidates, within the Swift/UVOT field, to analyze their properties. Out of\u0000these, 8 BSS candidates and both the YSS candidates are successfully fitted\u0000with single-component SEDs. Five BSS candidates show marginal excess in the\u0000near-UV (fractional residual < 0.3 in all but one UVOT filter), whereas three\u0000BSS candidates show moderate to significant excess in the near-UV (fractional\u0000residual > 0.3 in at least two UVOT filters). We present the properties of the\u0000BSS and YSS candidates, estimated based on the SED fits.","PeriodicalId":501068,"journal":{"name":"arXiv - PHYS - Solar and Stellar Astrophysics","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2024-09-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142257927","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Denoising medium resolution stellar spectra with neural networks","authors":"Balázs Pál, László Dobos","doi":"arxiv-2409.11625","DOIUrl":"https://doi.org/arxiv-2409.11625","url":null,"abstract":"We trained denoiser autoencoding neural networks on medium resolution\u0000simulated optical spectra of late-type stars to demonstrate that the\u0000reconstruction of the original flux is possible at a typical relative error of\u0000a fraction of a percent down to a typical signal-to-noise ratio of 10 per\u0000pixel. We show that relatively simple networks are capable of learning the\u0000characteristics of stellar spectra while still flexible enough to adapt to\u0000different values of extinction and fluxing imperfections that modifies the\u0000overall shape of the continuum, as well as to different values of Doppler\u0000shift. Denoised spectra can be used to find initial values for traditional\u0000stellar template fitting algorithms and - since evaluation of pre-trained\u0000neural networks is significantly faster than traditional template fitting -\u0000denoiser networks can be useful when a fast analysis of the noisy spectrum is\u0000necessary, for example during observations, between individual exposures.","PeriodicalId":501068,"journal":{"name":"arXiv - PHYS - Solar and Stellar Astrophysics","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2024-09-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142257933","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Exoplanet accretion monitoring spectroscopic survey (ENTROPY) I. Evidence for magnetospheric accretion in the young isolated planetary-mass object 2MASS J11151597+1937266","authors":"Gayathri Viswanath, Simon C. Ringqvist, Dorian Demars, Markus Janson, Mickaël Bonnefoy, Yuhiko Aoyama, Gabriel-Dominique Marleau, Catherine Dougados, Judit Szulágyi, Thanawuth Thanathibodee","doi":"arxiv-2409.12187","DOIUrl":"https://doi.org/arxiv-2409.12187","url":null,"abstract":"Accretion among planets is a poorly understood phenomenon, due to lack of\u0000both observational and theoretical studies. Detection of emission lines from\u0000accreting gas giants facilitate detailed investigations into this process. This\u0000work presents a detailed analysis of Balmer lines from one of the few known\u0000young, planetary-mass objects with observed emission, the isolated L2 dwarf\u00002MASS J11151597+1937266 with a mass 7-21 Mj and age 5-45 Myr, located at 45+-2\u0000pc. We obtained the first high-resolution (R~50,000) spectrum of the target\u0000with VLT/UVES, a spectrograph in the near-UV to visible wavelengths (3200-6800\u0000AA). We report resolved H3-H6 and He I (5875.6 AA) emission in the spectrum.\u0000Based on the asymmetric line profiles of H3 and H4, 10% width of H3 (199+-1\u0000km/s), tentative He I 6678 AA emission and indications of a disk from MIR\u0000excess, we confirm ongoing accretion at this object. Using the Gaia update of\u0000the parallax, we revise its temperature to 1816+-63 K and radius to 1.5+-0.1\u0000Rj. Analysis of observed H I profiles using 1D planet-surface shock model\u0000implies a pre-shock gas velocity of v0=120(+80,-40) km/s and a pre-shock\u0000density of log(n0/cm^-3)=14(+0,-5). Pre-shock velocity points to a mass of\u00006(+8,-4) Mj for the target. Combining the H I line luminosities and planetary\u0000Lline-Lacc scaling relations, we derive a mass accretion rate of\u00001.4(+2.8,-0.9)x10^-8 Mj/yr.","PeriodicalId":501068,"journal":{"name":"arXiv - PHYS - Solar and Stellar Astrophysics","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2024-09-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142257935","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"SWEET-Cat: A view on the planetary mass-radius relation","authors":"S. G. Sousa, V. Adibekyan, E. Delgado-Mena, N. C. Santos, B. Rojas-Ayala, S. C. Barros, O. D. S. Demangeon, S. Hoyer, G. Israelian, A. Mortier, B. M. T. Soares, M. Tsantaki","doi":"arxiv-2409.11965","DOIUrl":"https://doi.org/arxiv-2409.11965","url":null,"abstract":"SWEET-Cat (Stars With ExoplanETs Catalogue) was originally introduced in\u00002013, and since then, the number of confirmed exoplanets has increased\u0000significantly. A crucial step for a comprehensive understanding of these new\u0000worlds is the precise and homogeneous characterization of their host stars. We\u0000used a large number of high-resolution spectra to continue the addition of new\u0000stellar parameters for planet-host stars in SWEET-Cat following the new\u0000detection of exoplanets listed both at the Extrasolar Planets Encyclopedia and\u0000at the NASA exoplanet archive. We obtained high-resolution spectra for a\u0000significant number of these planet-host stars, either observed by our team or\u0000collected through public archives. For FGK stars, the spectroscopic stellar\u0000parameters were derived for the spectra following the same homogeneous process\u0000using ARES+MOOG as for the previous SWEET-Cat releases. The stellar properties\u0000are combined with the planet properties to study possible correlations that\u0000could shed more light into the star-planet connection studies. We increase the\u0000number of stars with homogeneous parameters by 232 ($sim$ 25% - from 959 to\u00001191). We then focus on the exoplanets with both mass and radius determined to\u0000review the mass-radius relation where we find consistent results with the ones\u0000previously reported in the literature. For the massive planets we also revisit\u0000the radius anomaly where we confirm a metallicity correlation for the radius\u0000anomaly already hinted in previous results.","PeriodicalId":501068,"journal":{"name":"arXiv - PHYS - Solar and Stellar Astrophysics","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2024-09-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142269172","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"IBEX Observations of Elastic Scattering of Interstellar Helium by Solar Wind Particles","authors":"H. Islam, N. Schwadron, E. Moebius, F. Rahmanifard, J. M. Sokol, A. Galli, D. J. McComas, P. Wurz, S. A. Fuselier, K. Fairchild, D. Heirtzler","doi":"arxiv-2409.11784","DOIUrl":"https://doi.org/arxiv-2409.11784","url":null,"abstract":"The IBEX-Lo instrument on the Interstellar Boundary Explorer (IBEX) mission\u0000observes primary and secondary interstellar helium in its 4 lowest energy\u0000steps. Observations of these helium populations have been systematically\u0000analyzed and compared to simulations using the analytic full integration of\u0000neutrals model (aFINM). A systematic difference is observed between the\u0000simulations and observations of secondary helium during solar cycle (SC) 24. We\u0000show that elastic scattering of primary helium by solar wind protons, which\u0000redistributes atoms from the core of the flux distribution, provides an\u0000explanation of the observed divergence from simulations. We verify that elastic\u0000scattering forms a halo in the wings of the primary He distribution in the\u0000spin-angle direction. Correcting the simulation for the effects of elastic\u0000scattering requires an increase of the estimated density of primary helium\u0000compared to previous estimates by Ulysses/GAS. Thus, based on our analysis of\u0000IBEX observations and $chi ^2$ minimization of simulation data that include\u0000the effects of elastic scattering, any estimation of neutral interstellar\u0000helium density at 1 AU by direct detection of the peak flux of neutral helium\u0000needs to be adjusted by $~sim$ 10%","PeriodicalId":501068,"journal":{"name":"arXiv - PHYS - Solar and Stellar Astrophysics","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2024-09-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142257931","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Benchmarking the spectroscopic masses of 249 evolved stars using asteroseismology with TESS","authors":"Sai Prathyusha Malla, Dennis Stello, Benjamin T. Monet, Daniel Huber, Marc Hon, Timothy R. Bedding, Claudia Reyes, Daniel R. Hey","doi":"arxiv-2409.11736","DOIUrl":"https://doi.org/arxiv-2409.11736","url":null,"abstract":"One way to understand planet formation is through studying the correlations\u0000between planet occurrence rates and stellar mass. However, measuring stellar\u0000mass in the red giant regime is very difficult. In particular, the\u0000spectroscopic masses of certain evolved stars, often referred to as \"retired\u0000A-stars\", have been questioned in the literature. Efforts to resolve this mass\u0000controversy using spectroscopy, interferometry and asteroseismology have so far\u0000been inconclusive. A recent ensemble study found a mass-dependent mass offset,\u0000but the result was based on only 16 stars. With NASA's Transiting Exoplanet\u0000Survey Satellite (TESS), we expand the investigation of the mass discrepancy to\u0000a total of 92 low-luminosity stars, synonymous with the retired A-stars. We\u0000measure their characteristic oscillation frequency,\u0000$mathrm{nu}_{mathrm{max}}$, and the large frequency separation,\u0000$mathrm{Deltanu}$, from their TESS photometric time series. Using these\u0000measurements and asteroseismic scaling relations, we derive asteroseismic\u0000masses and compare them with spectroscopic masses from five surveys, to\u0000comprehensively study the alleged mass-dependent mass offset. We find a mass\u0000offset between spectroscopy and seismology that increases with stellar mass.\u0000However, we note that adopting the seismic mass scale does not have a\u0000significant effect on the planet occurrence-mass-metallicity correlation for\u0000the so-called retired A-stars. We also report seismic measurements and masses\u0000for 157 higher luminosity giants (mostly helium-core-burning) from the\u0000spectroscopic surveys.","PeriodicalId":501068,"journal":{"name":"arXiv - PHYS - Solar and Stellar Astrophysics","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2024-09-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142257930","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Undersampling effects on observed periods of coronal oscillations","authors":"Daye Lim, Tom Van Doorsselaere, Valery M. Nakariakov, Dmitrii Y. Kolotkov, Yuhang Gao, David Berghmans","doi":"arxiv-2409.12095","DOIUrl":"https://doi.org/arxiv-2409.12095","url":null,"abstract":"Context. Recent observations of decayless transverse oscillations have shown\u0000two branches in the relationship between periods and loop lengths. One is a\u0000linear relationship, interpreted as a standing mode. The other shows almost no\u0000correlation and has not yet been interpreted conclusively. Aims. We\u0000investigated the undersampling effect on observed periods of decayless\u0000oscillations. Methods. We considered oscillating coronal loops that closely\u0000follow the observed loop length distribution. Assuming that all oscillations\u0000are standing waves, we modeled a signal that represents decayless oscillations\u0000where the period is proportional to the loop length and the amplitude and phase\u0000are randomly drawn. A downsampled signal was generated from the original signal\u0000by considering different sample rates that mimic temporal cadences of\u0000telescopes, and periods for sampled signals were analysed using the fast\u0000Fourier transform. Results. When the sampling cadence is getting closer to the\u0000actual oscillation period, a tendency for overestimating periods in short loops\u0000is enhanced. The relationship between loop lengths and periods of the sampled\u0000signals shows the two branches as in the observation. Conclusions. We find that\u0000long periods of decayless oscillations occurring in short loops could be the\u0000result of undersampling.","PeriodicalId":501068,"journal":{"name":"arXiv - PHYS - Solar and Stellar Astrophysics","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2024-09-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142269169","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"MINDS. JWST-MIRI Observations of a Spatially Resolved Atomic Jet and Polychromatic Molecular Wind Toward SY Cha","authors":"Kamber R. Schwarz, Matthias Samland, Göran Olofsson, Thomas Henning, Andrew Sellek, Manuel Güdel, Benoît Tabone, Inga Kamp, Pierre-Olivier Lagage, Ewine F. van Dishoeck, Alessio Caratti o Garatti, Adrian M. Glauser, Tom P. Ray, Aditya M. Arabhavi, Valentin Christiaens, Riccardo Franceschi, Danny Gasman, Sierra L. Grant, Jayatee Kanwar, Till Kaeufer, Nicolas T. Kurtovic, Giulia Perotti, Milou Temmink, Marissa Vlasblom","doi":"arxiv-2409.11176","DOIUrl":"https://doi.org/arxiv-2409.11176","url":null,"abstract":"The removal of angular momentum from protostellar systems drives accretion\u0000onto the central star and may drive the dispersal of the protoplanetary disk.\u0000Winds and jets can contribute to removing angular momentum from the disk,\u0000though the dominant process remain unclear. To date, observational studies of\u0000resolved disk winds have mostly targeted highly inclined disks. We report the\u0000detection of extended H2 and [Ne II] emission toward the young stellar object\u0000SY Cha with the JWST Mid-InfraRed Instrument Medium Resolution Spectrometer\u0000(MIRI-MRS). This is one of the first polychromatic detections of extended H2\u0000toward a moderately inclined, i=51.1 degrees, Class II source. We measure the\u0000semi-opening angle of the H2 emission as well as build a rotation diagram to\u0000determine the H2 excitation temperature and abundance. We find a wide\u0000semi-opening angle, high temperature, and low column density for the H2\u0000emission, all of which are characteristic of a disk wind. These observations\u0000demonstrate MIRI-MRS's utility in expanding studies of resolved disk winds\u0000beyond edge-on sources.","PeriodicalId":501068,"journal":{"name":"arXiv - PHYS - Solar and Stellar Astrophysics","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2024-09-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142257977","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Instability and warping in vertically oscillating accretion discs","authors":"Loren E. Held, Gordon I. Ogilvie","doi":"arxiv-2409.11490","DOIUrl":"https://doi.org/arxiv-2409.11490","url":null,"abstract":"Many accretion discs have been found to be distorted: either warped due a\u0000misalignment in the system, or non-circular as a result of orbital eccentricity\u0000or tidal deformation by a binary companion. Warped, eccentric, and tidally\u0000distorted discs are not in vertical hydrostatic equilibrium, and thus exhibit\u0000vertical oscillations in the direction perpendicular to the disc, a phenomenon\u0000that is absent in circular and flat discs. In extreme cases, this vertical\u0000motion is manifested as a vertical `bouncing' of the gas, potentially leading\u0000to shocks and heating, as observed in recent global numerical simulations. In\u0000this paper we isolate the mechanics of vertical disc oscillations by means of\u0000quasi-2D and fully 3D hydrodynamic local (shearing-box) models. To determine\u0000the numerical and physical dissipation mechanisms at work during an oscillation\u0000we start by investigating unforced oscillations, examining the effect of\u0000initial oscillation amplitude, as well as resolution, boundary conditions, and\u0000vertical box size on the dissipation and energetics of the oscillations. We\u0000then drive the oscillations by introducing a time-dependent gravitational\u0000potential. A key result is that even a purely vertically oscillating disc is\u0000(parametrically) unstable to developing inertial waves, as we confirm through a\u0000linear stability analysis. The most important of these has the character of a\u0000bending wave, whose radial wavelength depends on the frequency of the vertical\u0000oscillation. The nonlinear phase of the instability exhibits shocks, which\u0000dampen the oscillations, although energy can also flow from the bending wave\u0000back to the vertical oscillation.","PeriodicalId":501068,"journal":{"name":"arXiv - PHYS - Solar and Stellar Astrophysics","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2024-09-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142257932","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}