Large Error Bars Research Articles

Toroidal injection angle dependence of EC assisted plasma initiation at DIII-D

Abstract An experimental scan of the electron cyclotron waves (EC) toroidal injection angle in plasma breakdown is performed at the DIII-D tokamak. The second harmonic, extraordinary mode EC is used for the study. The dependence of n e and T e on the EC injection angle cannot be conclusively drawn from this study due to the large error bars in the n e and T e measurements. On the other hand, high T e data points are observed in some discharges which can be explained by nonlinear heating. The D α emission measurement shows a clear relation between the breakdown time and the injection angle. An experimental investigation of the cause of the dependence of breakdown delay on the EC injection angle suggests that when the injection angle is oblique, the EC heating after the reflection at the inboard wall may become ineffective and cause the breakdown delay even when the EC heating before and directly upon injection remains effective. A preliminary run of the heat and transport balance code DYON indicates that the obtained dataset is suitable for a quantitative validation of EC absorption models.

On approximations of the redshift-space bispectrum and power spectrum multipoles covariance matrix

We investigate, in dark matter and galaxy mocks, the effects of approximating the galaxy power spectrum-bispectrum estimated covariance as a diagonal matrix, for an analysis that aligns with the specifications of recent and upcoming galaxy surveys. We find that, for a joint power spectrum and bispectrum data-vector, with corresponding k-ranges of 0.02 < k[hMpc-1] < 0.15 and 0.02 < k[hMpc-1] < 0.12 each, the diagonal covariance approximation recovers ∼ 10% larger error-bars on the parameters {σ 8,f,α ∥,α ⊥} with respect to the full covariance case, while still underestimating the corresponding true errors on the recovered parameters by ∼ 10%. This is caused by the diagonal approximations weighting the elements of the data-vector in a sub-optimal way, resulting in a less efficient estimator, with poor coverage properties, than the maximum likelihood estimator featuring the full covariance matrix. We further investigate intermediate approximations to the full covariance matrix, with up to ∼ 80% of the matrix elements being zero, which could be advantageous for theoretical and hybrid approaches. We expect these results to be qualitatively insensitive to variations of the total cosmological volume, depending primarily on the bin size and shot-noise, thus making them particularly significantfor present and future galaxy surveys.

Development of Amorphous Solid Dispersion Sustained-Release Formulations with Polymer Composite Matrix-Regulated Stable Release Plateaus.

This study was designed to develop ibuprofen (IBU) sustained-release amorphous solid dispersion (ASD) using polymer composites matrix with drug release plateaus for stable release and to further reveal intrinsic links between polymer' matrix ratios and drug release behaviors. Hydrophilic polymers and hydrophobic polymers were combined to form different composite matrices in developing IBU ASD formulations by hot melt extrusion technique. The intrinsic links between the mixed polymer matrix ratio and drug dissolution behaviors was deeply clarified from the dissolution curves of hydrophilic polymers and swelling curves of composite matrices, and intermolecular forces among the components in ASDs. IBU + ammonio methacrylate copolymer type B (RSPO) + poly(1-vinylpyrrolidone-co-vinyl acetate) (PVP VA64) physical mixtures presented unstable release behaviors with large error bars due to inhomogeneities at the micrometer level. However, IBU-RSPO-PVP VA64 ASDs showed a "dissolution plateau phenomenon", i.e., release behaviors of IBU in ASDs were unaffected by polymer ratios when PVP VA64 content was 35% ~ 50%, which could reduce risks of variations in release behaviors due to fluctuations in prescriptions/processes. The release of IBU in ASDs was simultaneously regulated by the PVP VA64-mediated "dissolution" and RSPO-PVP VA64 assembly-mediated "swelling". Radial distribution function suggested that similar intermolecular forces between RSPO and PVP VA64 were key mechanisms for the "dissolution plateau phenomenon" in ASDs at 35% ~ 50% of PVP VA64. This study provided ideas for developing ASD sustained-release formulations with stable release plateau modulated by polymer combinations, taking full advantages of simple process/prescription, ease of scale-up and favorable release behavior of ASD formulations.

Towards absolutely calibrated ECE Michelson measurements in EC heated plasmas at W7-X

A Michelson Interferometer is in use at Wendelstein 7-X (W7-X) to probe the Electron Cyclotron Emission (ECE) spectrum [1], [2], [3]. During the past operational campaign (OP2.1), 2nd and 3rd harmonic ECE power density spectra have been routinely recorded in the presence of X2and O2-mode Electron Cyclotron Resonance Heating (ECRH). However, combination of the particular notch filter arrangement and high transmission line losses have thus far prevented overall calibration using a hot source cold source exposure at the input antenna. As an alternative, the response of the individual components is measured and summed. While reasonable numbers on electron temperature are obtained in X2-mode polarisation, interaction between front-end components is neglected and large error bars must be assumed. But the information on the individual components, together with synthetic modelling and data from experiment (OP2.1), has been used to design a new front-end with improved S/N. This optimisation is discussed in this paper with focus on notch filter selection, a new transmission line (Tx-line) and a novel combined quasi-optical taper / polarizer tuner.

Double black hole mergers in nuclear star clusters: eccentricities, spins, masses, and the growth of massive seeds

ABSTRACT We investigate the formation of intermediate mass black holes (IMBHs) through hierarchical mergers of stellar origin black holes (BHs), as well as BH mergers formed dynamically in nuclear star clusters. Using a semi-analytical approach that incorporates probabilistic mass-function-dependent double BH (DBH) pairing, binary-single encounters, and a mass-ratio-dependent prescription for energy dissipation in hardening binaries, we find that IMBHs with masses of $\mathcal {O}(10^2)$–$\mathcal {O}(10^4)\, \rm M_\odot$ can be formed solely through hierarchical mergers in time-scales of a few 100 Myrs to a few Gyrs. Clusters with escape velocities ≳400 km s−1 inevitably form high-mass IMBHs. The spin distribution of IMBHs with masses ≳ 103 M⊙ is strongly clustered at χ ∼ 0.15; while for lower masses, it peaks at χ ∼ 0.7. Eccentric mergers are more frequent for equal-mass binaries containing first- and/or second-generation BHs. Metal-rich, young, dense clusters can produce up to 20 per cent of their DBH mergers with eccentricity ≥0.1 at $10\, \rm Hz$, and ∼2–9 per cent of all in-cluster mergers can form at &amp;gt;10 Hz. Nuclear star clusters are therefore promising environments for the formation of highly eccentric DBH mergers, detectable with current gravitational-wave detectors. Clusters of extreme mass (∼108 M⊙) and density (∼108 M⊙ pc−3) can have about half of all of their DBH mergers with primary masses ≥100 M⊙. The fraction of in-cluster mergers increases rapidly with increasing cluster escape velocity, being nearly unity for vesc ≳ 200 km s−1. Cosmological merger rate of DBHs from nuclear clusters varies ⪅0.01–1 Gpc−3 yr−1, where the large error bars come from uncertainties in the cluster initial conditions, number density distribution, and redshift evolution of nucleated galaxies.

Interactions of omega mesons in nuclear matter and with nuclei

In-medium interactions of omega -mesons in infinite nuclear matter and finite nuclei are investigated in a microscopic approach, focused on the particle-hole excitations of the medium involving nucleonic NN^{-1} and N^*N^{-1} modes, where N^* denotes a nucleon resonance. The nuclear polarization tensors include relativistic mean-field dynamics by self–consistent scalar and vector fields. The resulting self-energies are transmitted to finite nuclei in local density approximation. Real and imaginary parts of longitudinal and transversal self-energies are discussed. The relation of the present approach to meson cloud models is addressed and an ambiguity is pointed out. Applications to recent data on the in–medium width of omega mesons scattered on a Niobium target serve to determine unknown N^*Nomega in-medium coupling constants. The data are well described by N^*N^{-1} self–energies containing S–wave and P-wave N^* resonances. Exploratory investigations, however, show that the spectroscopic composition of self-energies depends crucially on the near-threshold properties of the width which at present is known only within large error bars. The calculations predict the prevalence of transversal self–energies, implying that vector current conservation is still maintained in the nuclear medium by slightly more than 90%. Schrödinger-equivalent potentials are derived and scattering lengths and effective range parameters are extracted for the longitudinal and transversal channel. Longitudinal and transversal spectral distributions are discussed and the dependencies on momentum and nuclear density are investigated. Schrödinger-type omega +{}^{93}Nb optical potentials are constructed. Low-energy parameters are determined, are used to study the pole structure of the S-matrix at threshold. The effective range expansion of the omega-nucleus K-matrix led to a omega +{}^{93}Nb bound states with binding energy Re(varepsilon _B)=-448 keV but of width Gamma _B=4445 keV.

High-level ab initio composites: thermochemical bond dissociation energies for vanadium species

Bond dissociation energies (BDE) are among the most sought-after properties in chemistry. Accurate prediction of BDE’s for transition metal species can be daunting for both experiment and computation. Experimental data has been limited and often has large error bars, making the identification of suitable computational methods difficult. Recent advancements in the experimental determination of BDE’s with techniques such as Velocity Map Imaging and 2 Photon Ionisation now provide useful gauges for computational strategies and new methodologies. The vanadium diatomics have been challenging for computational chemistry methods, and, thus, a new experimental gauge enables methods to be reevaluated and developed for these species. Herein, the super-correlation consistent Composite (s-ccCA), a thermochemical scheme centered around CCSD(T)/complete basis set (CBS) limit computations with additional contributions that account for scalar-relativistic effects, and coupled cluster contributions up to quintuple excitations has been considered. The agreement between the s-ccCA scheme and by recent experiments is excellent, demonstrating the utility of the new approach in addressing challenging systems, even those of multireference nature. The longstanding correlation consistent composite approach (ccCA) is also reevaluated for the vanadium species and find that the mean absolute deviation (MAD) is greatly reduced compared to previously used experimental values.

Physics Considerations for Evaluation of Dose for Dose-Response Models of Pediatric Late Effects From Radiation Therapy: A PENTEC Introductory Review

We describe the methods used to estimate the accuracy of dosimetric data found in literature sources used to construct the Pediatric Normal Tissue Effects in the Clinic (PENTEC) dose-response models, summarize these findings of each organ-specific task force, describe some of the dosimetric challenges and the extent to which these efforts affected the final modeling results, and provide guidance on the interpretation of the dose-response results given the various dosimetric uncertainties. Each of the PENTEC task force medical physicists reviewed all the journal articles used for dose-response modeling to identify, categorize, and quantify dosimetric uncertainties. These uncertainties fell into 6 broad categories. A uniform nomenclature was developed for describing the "dosimetric quality" of the articles used in the PENTEC reviews. Among the multidisciplinary experts in the PENTEC effort, the medical physicists were charged with the dosimetric evaluation, as they are most expert in this subject. The percentage dosimetric uncertainty was estimated for each late effect endpoint for all PENTEC organ reports. Twelve specific sources of dose uncertainty were identified related to the 6 broad categories. The most common reason for organ dose uncertainty was that prescribed dose rather than organ dose was reported. Percentage dose uncertainties ranged from 5% to 200%. Systematic uncertainties were used to correct the dose component of the models. Random uncertainties were also described in each report and in some cases used to modify dose axis error bars. In addition, the potential effects of dose binning were described. PENTEC reports are designed to provide guidance to radiation oncologists and treatment planners for organ dose constraints. It is critical that these dose constraint recommendations are as accurate as possible, acknowledging the large error bars for many. Achieving this accuracy is important as it enables clinicians to better balance target dose coverage with risk of late effects. Evidence-based dose constraints for pediatric patients have been lacking and, in this regard, PENTEC fills an important unmet need. One must be aware of the limitations of our recommendations, and that for some organ systems, large uncertainties exist in the dose-response model because of clinical endpoint uncertainty, dosimetric uncertainty, or both.

The scalings of the thermal energy confinement time in EAST H-mode plasmas

This paper describes scalings of the H-mode confinement database of neutral beam injection (NBI)-lower hybrid wave (LHW) and electron cyclotron resonant heating-LHW plasmas in the EAST tokamak. Fundamental information of the EAST H-mode database and the details of calculation of the thermal energy confinement time in EAST are presented. The result of the scaling model of the thermal energy confinement time in NBI-LHW plasmas with root-mean-square-error , compared with the multi-machine scaling model derived from the multi-machine database (mainly NBI heating) with , is obtained. The scaling presents a similar dependency on plasma current and power loss and a lower dependency on plasma density and elongation, but stronger dependency on toroidal field than in . The scaling demonstrates a similar dependency on plasma current and power loss and lower dependency on plasma density, but a negative dependency with large error bars on elongation compared with in NBI-LHW plasmas. The comparison of EAST models with the more recent multi-tokamak scaling ITPA20-IL shows a similar engineering dependency on plasma current, power loss and plasma density, but opposite dependency on toroidal field.

Impact of large-mass constraints on the properties of neutron stars

ABSTRACT The maximum mass of a non-rotating neutron star, MTOV, plays a very important role in deciphering the structure and composition of neutron stars and in revealing the equation of state (EOS) of nuclear matter. Although with a large-error bar, the recent mass estimate for the black-widow binary pulsar PSR J0952–0607, i.e. M = 2.35 ± 0.17 M⊙, provides the strongest lower bound on MTOV and suggests that neutron stars with very large masses can, in principle, be observed. Adopting an agnostic modelling of the EOS, we study the impact that large masses have on the neutron-star properties. In particular, we show that assuming $M_{\rm TOV}\gtrsim 2.35\, {\rm M_\odot}$ constrains tightly the behaviour of the pressure as a function of the energy density and moves the lower bounds for the stellar radii to values that are significantly larger than those constrained by the NICER measurements, rendering the latter ineffective in constraining the EOS. We also provide updated analytic expressions for the lower bound on the binary tidal deformability in terms of the chirp mass and show how larger bounds on MTOV lead to tighter constraints for this quantity. In addition, we point out a novel quasi-universal relation for the pressure profile inside neutron stars that is only weakly dependent on the EOS and the maximum-mass constraint. Finally, we study how the sound speed and the conformal anomaly are distributed inside neutron stars and show how these quantities depend on the imposed maximum-mass constraints.

Analysis of four solar occultations by Titan’s atmosphere with the infrared channel of the VIMS instrument: Haze, CH4, CH3D, and CO vertical profiles

Titan, the largest satellite of Saturn, has a dense atmosphere mainly composed of nitrogen, methane at a percent level, and minor species. It is also covered by a thick and global photochemical organic haze. In the last two decades, the observations made by the Cassini orbiter and the Huygens probe have greatly improved our knowledge of Titan's system. The surface, haze, clouds, and chemical species can be studied and characterised with several instruments simultaneously. On the other hand, some compounds of its climatic cycle remain poorly known. This is clearly the case of the methane cycle, which is, however, a critical component of Titan's climate and of its evolution. We reanalysed four solar occultations by Titan's atmosphere observed with the infrared part of the Visual Infrared Mapping Spectrometer (VIMS) instrument. These observations were already analysed, but here we used significantly improved methane spectroscopic data. We retrieved the haze properties (not treated previously) and the mixing ratios of methane, deuterated methane, and CO in the stratosphere and in the low mesosphere. The methane mixing ratio in the stratosphere is much lower (about 1.1%) than expected from Huygens measurements (about 1.4 to 1.5%). This is consistent with previous results obtained with other instruments. However, features in the methane vertical profiles clearly demonstrate that there are interactions between the methane distribution and the atmosphere circulation. We also retrieved the haze extinction profiles and the haze spectral behaviour. We find that aerosols are aggregates with a fractal dimension of Df ≃ 2.3 ± 0.1, rather than Df ≃ 2 as previously thought. Our analysis also reveals noticeable changes in their size distribution and their morphology with altitude and time. These changes are also clearly connected to the atmosphere circulation and concerns the whole stratosphere and the transition between the main and the detached haze layers. We finally display the vertical profiles of CH3D and CO for the four observations. Although the latter retrievals have large error bars due to noisy data, we could derive values in agreement with other works.

Dependency of the cosmographic tension of standard model to statistical errors of observational data ‎

In this work, we study the standard model of cosmology in the context of cosmographic approach. We want to determine whether the cosmographic tension of the standard model that is reported in recent studies, depends on the statistical errors of the observational data or not. To do this, we produce three catalogues of mock data for the distance modulus of type Ia supernovae using a canonical value for matter density in the framework of standard model. In the first catalogue, the errors of mock data have been chosen equal to the errors of real data in Pantheon catalogue. In the second and third catalogues, the errors of mock data have been chosen equal to half and twice the real errors in Pantheon sample, respectively. In the next step, using the generated mock data, we minimize the least square function in the context of Markov Chain Monte Carlo method and put constraints on the cosmographic parameters in both model independent cosmographic approach and standard model. Our results show that decreasing the error of mock data can remove the cosmographic tension of the standard model. Also, the larger errors increase the deviation of standard model from cosmographic method. Hence, the cosmographic tension of the standard model which is recently reported by the Hubble diagrams of quasars and Gamma-Ray-Burst can be essentially due to large error bars of these observational data and so not a physical tension.

Elastic α−C12 scattering at low energies with the resonant 22+ and 23+ states of O16

The elastic $\alpha$-$^{12}$C scattering for $l=2$ at low energies is studied in an effective Lagrangian approach. We explicitly include two resonant $2_2^+$ and $2_3^+$ states of $^{16}$O in the scattering amplitudes and construct an $S$ matrix assuming that three amplitudes, the non-resonant part of the amplitude which has the sub-threshold $2_1^+$ state of $^{16}$O and those of the two resonant states, are represented by the summation of corresponding parts of the phase shift. Then, we fit the parameters in the $S$ matrix to the phase shift data by imposing three conditions at very low energies where the phase shift data are not available. By using the fitted parameters, we calculate the asymptotic normalization coefficients (ANC) of the $2_1^+$ state of $^{16}$O and find that the previously reported small and large values of the ANC can be reproduced depending on the imposed conditions, but we obtain large error bars for the large ANC values which are reported from the $\alpha$ transfer reactions.

Experimental and numerical modelling of mass transfer in a refining ladle

Mass transfer between liquid steel and slag is an important physical phenomenon during secondary metallurgy for prediction of the chemical reaction rate and adjustment of liquid steel composition. We study this phenomenon at ambient temperature with a water experiment and perform Direct Numerical Simulations, aiming to reproduce an argon-gas bottom-blown ladle. First, we measure the evolution of the time-averaged open-eye area as a function of the air flow rate. Both simulation and experiment agree relatively well and are close to other water experiments in the literature. Secondly, the mass transfer of thymol between water and oil is investigated. The experimental results show that two mass transfer regimes can be observed. The regime change coincides with atomization of the oil layer resulting in the continuous formation of oil droplets in the water whenever the air flow rate rises above a critical value. The numerical results for the mass-transfer rate or Sherwood number are obtained at small Schmidt numbers and are then extrapolated to the experimental Schmidt number of 1480. A good agreement with experiment is observed although with large error bars. The Sherwood numbers at the two largest simulated flow rates show a steep increase.

Complete characterization of a lithium battery electrolyte using a combination of electrophoretic NMR and electrochemical methods.

Improving transport properties of electrolytes is important for developing lithium-ion batteries for future energy storage applications. In Newman's concentrated solution theory, electrolytes are characterized by three transport parameters, conductivity, diffusion coefficient, and transference number, in addition to the thermodynamic factor. In this work, these parameters are all determined for an exemplar liquid electrolyte, lithium bis(trifluoromethanesulfonyl)imide mixed in tetraethylene glycol dimethyl ether, using electrochemical methods. The intrinsic coupling between parameters obtained by electrochemical methods results in large error bars in the transference number that obscure the transport behavior of the electrolyte. Here, we use electrophoretic NMR (eNMR) to measure the electric-field-induced ion and solvent velocities to obtain the transference number directly, which enables determination of the thermodynamic factor with greater certainty. Our work indicates that the combination of eNMR and electrochemical methods provides a robust approach for complete characterization of battery electrolytes.

Sensitivity analysis of ice/dust aerosol and phase function assumptions on Hapke spectral unmixing and band depth parameters of martian water ice

Spectral data from the Compact Reconnaissance Imaging Spectrometer for Mars (CRISM), specifically full-resolution targeted (FRT) observations, can provide quantitative information about the martian polar surface at local scales; however, it has been minimally used in such ways. This is partly due to the challenging feat of photometric and atmospheric data corrections needed, especially for icy surfaces at the poles. The scattering behavior of the dirty ice is not well-constrained. The presence of dust and ice aerosols makes it difficult to retrieve the surface's inherent albedos needed for quantitative studies of polar ice. The following work demonstrates how the limited phase angle range of CRISM “central scene” data and the assumptions made about the properties and conditions of the atmosphere (ice and dust aerosol opacity) and surface (surface phase function) going into the processing and correction of the data affect the derived surface properties of the north polar ice cap of Mars (i.e., H2O ice band depth parameter and Hapke-modeled grain size and abundance). Through this work, we discovered the following. 1) Both dirty ice and more pure ice were best modeled as broad, moderate forward scatterers out of the four different behaviors tested. 2) The sensitivity of Hapke-modeled grain size and abundance to ice and dust aerosol opacity and phase function uncertainty is minor (well below Hapke model error). However, all possible measures should be taken to not propagate more error since Hapke modeling already inherently has large error bars (10–30%). 3) H2O index values are affected—up to ~10% deviation—when aerosols are untreated or not treated appropriately. This should only be of concern for temporal studies. 4) Hapke-modeled grain size and abundance estimates were most sensitive to the phase angle range used for the retrieval of SSA.

Constraining the Orbit and Mass of epsilon Eridani b with Radial Velocities, Hipparcos IAD-Gaia DR2 Astrometry, and Multiepoch Vortex Coronagraphy Upper Limits

Abstract ϵ Eridani is a young planetary system hosting a complex multibelt debris disk and a confirmed Jupiter-like planet orbiting at 3.48 au from its host star. Its age and architecture are thus reminiscent of the early Solar System. The most recent study of Mawet et al., which combined radial-velocity data and Ms-band direct imaging upper limits, started to constrain the planet’s orbital parameters and mass, but are still affected by large error bars and degeneracies. Here we make use of the most recent data compilation from three different techniques to further refine ϵ Eridani b’s properties: RVs, absolute astrometry measurements from the Hipparcos and Gaia missions, and new Keck/NIRC2 Ms-band vortex coronagraph images. We combine this data in a Bayesian framework. We find a new mass, M b = 0.66 − 0.09 + 0.12 MJup, and inclination, i = 78 . 81 − 22.41 ° + 29.34 , with at least a factor 2 of improvement over previous uncertainties. We also report updated constraints on the longitude of the ascending node, the argument of the periastron, and the time of periastron passage. With these updated parameters, we can better predict the position of the planet at any past and future epoch, which can greatly help define the strategy and planning of future observations and with subsequent data analysis. In particular, these results can assist the search for a direct detection with JWST and the Nancy Grace Roman Space Telescope’s coronagraph instrument.

The updated ITPA global H-mode confinement database: description and analysis

The multi-machine International Tokamak Physics Activity (ITPA) Global H-mode Confinement Database has been upgraded with new data from JET with the ITER-like wall and ASDEX Upgrade with the full tungsten wall. This paper describes the new database and presents results of regression analysis to estimate the global energy confinement scaling in H-mode plasmas using a standard power law. Various subsets of the database are considered, focusing on type of wall and divertor materials, confinement regime (all H-modes, ELMy H or ELM-free) and ITER-like constraints. Apart from ordinary least squares (OLS), two other, robust regression techniques are applied, which take into account uncertainty on all variables. Regression on data from individual devices shows that, generally, the confinement dependence on density and the power degradation are weakest in the fully metallic devices. Using the multi-machine scalings, predictions are made of the confinement time in a standard ELMy H-mode scenario in ITER. The uncertainty on the scaling parameters is discussed with a view to practically useful error bars on the parameters and predictions. One of the derived scalings for ELMy H-modes on an ITER-like subset is studied in particular and compared to the IPB98(y, 2) confinement scaling in engineering and dimensionless form. Transformation of this new scaling from engineering variables to dimensionless quantities is shown to result in large error bars on the dimensionless scaling. Regression analysis in the space of dimensionless variables is therefore proposed as an alternative, yielding acceptable estimates for the dimensionless scaling. The new scaling, which is dimensionally correct within the uncertainties, suggests that some dependencies of confinement in the multi-machine database can be reconciled with parameter scans in individual devices. This includes vanishingly small dependence of confinement on line-averaged density and normalized plasma pressure (β), as well as a noticeable, positive dependence on effective atomic mass and plasma triangularity. Extrapolation of this scaling to ITER yields a somewhat lower confinement time compared to the IPB98(y, 2) prediction, possibly related to the considerably weaker dependence on major radius in the new scaling (slightly above linear). Further studies are needed to compare more flexible regression models with the power law used here. In addition, data from more devices concerning possible ‘hidden variables’ could help to determine their influence on confinement, while adding data in sparsely populated areas of the parameter space may contribute to further disentangling some of the global confinement dependencies in tokamak plasmas.

Changing Accretion Geometry of Seyfert 1 Mrk 335 with NuSTAR: A Comparative Study

We present a detailed spectral study of the narrow-line Seyfert 1 galaxy, Markarian 335, using eight epoch observations made between 2013 and 2020 with the Nuclear Spectroscopic Telescope Array. The source was variable during this period both in spectral flux and flow geometry. We estimated the height of the Compton cloud from the model fitted parameters for the whole observation period. This allowed us to investigate the underlying physical processes that drive the variability in X-rays. Our model fitted mass varies in a narrow range, between (2.44±0.45−3.04±0.56)×107M⊙, however, given the large error bars, it is consistent with being constant and is in agreement with that known from optical reverberation mapping observations. The disk mass accretion rate reached a maximum of 10% of the Eddington rate during June 2013. Our study sheds light on mass outflows from the system and also compares different aspects of accretion with X-ray binaries.

Yet another test of Radial Acceleration Relation for galaxy clusters

We carry out a test of the radial acceleration relation (RAR) for galaxy clusters from two different catalogs compiled in literature, as an independent cross-check of two recent analyses, which reached opposite conclusions. The datasets we considered include a Chandra sample of 12 clusters and the X-COP sample of 12 clusters. For both the samples, we find that the residual scatter is small (0.11-0.14 dex), although the best-fit values for the Chandra sample have large error bars. Therefore, we argue that at least one of these cluster samples (X-COP) obeys the radial acceleration relation. However, since the best-fit parameters are discrepant with each other as well as the previous estimates, we argue that the RAR is not universal. For both the catalogs, the acceleration scale, which we obtain is about an order of magnitude larger than that obtained for galaxies, and is agreement with both the recent estimates.