Miracle-dz/UniFAR-FTUs huggingface dataset:
Atmospheric tides in Earth-like planets

Atmospheric tides can strongly affect the rotational dynamics of planets. In the family of Earth-like planets, such as Venus, this physical mechanism coupled with solid tides makes the angular velocity evolve over long timescales and determines the equilibrium configurations of their spin. Contrary to the solid core, the atmosphere is submitted to both tidal gravitational potential and insolation flux coming from the star. The complex response of the gas is intrinsically linked to its physical properties. This dependence has to be characterized and quantified to study the large variety of extrasolar planetary systems. We develop a theoretical global model where radiative losses, which are predominant in slowly rotating atmospheres, are taken into account. We analytically compute the tidal perturbation of pressure, density, temperature and velocity field from which we deduce the expressions of atmospheric Love numbers and tidal torque exerted by the star. The dynamics of atmospheric tides depends on the frequency regime of the tidal perturbation: the thermal regime near synchronization and the dynamical regime characterizing fast-rotating planets. The dependence of the torque on the tidal frequency is quantified for Earth-like and Venus-like exoplanets and is in good agreement with the results given by Global Climate Models (GCM) simulations. Introducing dissipative processes such as radiation regularizes the tidal response of the atmosphere, otherwise it is singular at synchronization. We demonstrate the important role played by the physical and dynamical properties of a super-Earth atmosphere (e.g. Coriolis, stratification, background pressure, density, temperature, radiative emission) and point out the key parameters defining tidal regimes (e.g. inertia, Brunt-V\"ais\"al\"a, radiative frequencies, tidal frequency) and characterize the behaviour of the fluid shell with dissipation.
Estimation of mass outflow rates from dissipative accretion disc around rotating black holes

We study the properties of the dissipative accretion flow around rotating black holes in the presence of mass loss. We obtain a complete set of global inflow-outflowsolutions in the steady state by solving the underlying conservation equations self-consistently. We observe that global inflow-outflow solutions are not the isolated solution, instead such solutions are possible for wide range of inflow parameters. Accordingly, we identify the boundary of the parameter space for outflows, spanned by the angular momentum (lambda(in)) and the energy (epsilon(in)) at the inner sonic point (chi(in)), as a function of the dissipation parameters and find that parameter space gradually shrinks with the increase of dissipation rates. Further, we examine the properties of the outflow rate R-m (defined as the ratio of the outflow-to-inflow mass flux) and ascertain that dissipative processes play a decisive role in determining the outflow rates. We calculate the limits on the maximum outflow rate (R-m(max)) in terms of viscosity parameter (a) as well as the black hole spin (a(k)) and obtain the limiting range as 3 per cent = 0.57.
NIHAO - XIV. Reproducing the observed diversity of dwarf galaxy rotation curve shapes in ΛCDM

The significant diversity of rotation curve (RC) shapes in dwarf galaxies has recently emerged as a challenge to LCDM: in dark matter (DM) only simulations, DM halos have a universal cuspy density profile that results in self-similar RC shapes. We compare RC shapes of simulated galaxies from the NIHAO project with observed galaxies from the homogeneous SPARC dataset. The DM halos of the NIHAO galaxies can expand to form cores, with the degree of expansion depending on their stellar-to-halo mass ratio. By means of the $V_{\rm 2kpc}-V_{\rm Rlast}$ relation (where $V_{\rm Rlast}$ is the outermost measured rotation velocity), we show that both the average trend and the scatter in RC shapes of NIHAO galaxies are in reasonable agreement with SPARC: this represents a significant improvement compared to simulations that do not result in DM core formation, suggesting that halo expansion is a key process in matching the diversity of dwarf galaxy RCs. Note that NIHAO galaxies can reproduce even the extremely slowly rising RCs of IC 2574 and UGC 5750. Revealingly, the range where observed galaxies show the highest diversity corresponds to the range where core formation is most efficient in NIHAO simulations, 50$<V_{\rm Rlast}$\km s$^{-1}<$100. A few observed galaxies in this range cannot be matched by any NIHAO RC nor by simulations that predict a universal halo profile. Interestingly, the majority of these are starbursts or emission-line galaxies, with steep RCs and small effective radii. Such galaxies represent an interesting observational target providing new clues to the process/viability of cusp-core transformation, the relationship between starburst and inner potential well, and the nature of DM.
Different dust and gas radial extents in protoplanetary disks: consistent models of grain growth and CO emission

Context. ALMA observations of protoplanetary disks confirm earlier indications that there is a clear difference between the dust and gas radial extents. The origin of this difference is still debated, with both radial drift of the dust and optical depth effects suggested in the literature. Aims. In thermo-chemical models, the dust properties are usually prescribed by simple parametrisations. In this work, the feedback of more realistic dust particle distributions onto the gas chemistry and molecular emissivity is investigated, with a particular focus on CO isotopologues. Methods. The radial dust grain size distribution is determined using dust evolution models that include growth, fragmentation, and radial drift for a given static gas density structure. The vertical settling of dust particles is computed in steady-state. A new version of the code DALI is used to take into account how dust surface area and density influence the disk thermal structure, molecular abundances, and excitation. Synthetic images of both continuum thermal emission and low J CO isotopologues lines are produced. Results. The difference of dust and gas radial sizes is largely due to differences in the optical depth of CO lines and millimeter continuum, without the need to invoke radial drift. The effect of radial drift is primarily visible in the sharp outer edge of the continuum intensity profile. The gas outer radius probed by (CO)-C-12 emission can easily differ by a factor of similar to two between the models for a turbulent alpha ranging between 10(-4) and 10(-2), with the ratio of the CO and mm radius R-CO(out)/R-mm(out) increasing with turbulence. Grain growth and settling concur in thermally decoupling the gas and dust components, due to the low collision rate with large grains. As a result, the gas can be much colder than the dust at intermediate heights, reducing the CO excitation and emission, especially for low turbulence values. Also, due to disk mid-plane shadowing, a second CO thermal desorption (rather than photodesorption) front can occur in the warmer outer mid-plane disk. The models are compared to ALMA observations of HD 163296 as a test case. In order to reproduce the observed CO snowline of the system, a binding energy for CO typical of ice mixtures, with E-b >= 1100 K, needs to be used rather than the lower pure CO value. Conclusions. The difference between observed gas and dust extent is largely due to optical depth effects, but radial drift and grain size evolution also affect the gas and dust emission in subtle ways. In order to properly infer fundamental quantities of the gaseous component of disks, such as disk outer radii and gas surface density profiles, simultaneous modelling of both dust and gas observations including dust evolution is needed.
Quantifying tension: interpreting the DES evidence ratio

We provide a new interpretation for the Bayes factor combination used in the DES first year analysis to quantify the tension between the Dark Energy Survey (DES) and Planck datasets. The ratio quantifies a Bayesian confidence in our ability to combine the datasets. This interpretation is prior-dependent, with wider prior widths boosting the confidence. We therefore propose that if there are any reasonable priors which reduce the confidence to below unity, then we cannot assert that the datasets are compatible. Computing the evidence ratios for the DES first year analysis and Planck, given that narrower priors drop the confidence to below unity, we conclude that DES and Planck are, in a Bayesian sense, incompatible under $\Lambda$CDM. Additionally we compute ratios which confirm the consensus that measurements of the acoustic scale by the Baryon Oscillation Spectroscopic Survey (BOSS) are compatible with Planck, whilst direct measurements of the acceleration rate of the Universe by the SH0ES collaboration are not. We propose a modification to the Bayes ratio which removes the prior dependency using Kullback-Leibler divergences, and using this statistical test find Planck in strong tension with SH0ES in moderate tension with DES, and in no tension with BOSS. We propose this statistic as the optimal way to compare datasets, ahead of the next DES data releases, as well as future surveys. Finally, as an element of these calculations, we introduce in a cosmological setting the Bayesian model dimensionality, which is a parameterisation-independent measure of the number of parameters that a given dataset constrains.
Nonstandard heavy mesons and baryons: Experimental evidence

Quantum chromodynamics (QCD), the generally accepted theory for strong interactions, describes the interactions between quarks and gluons. The strongly interacting particles that are seen in nature are hadrons, which are composites of quarks and gluons. Since QCD is a strongly coupled theory at distance scales that are characteristic of observable hadrons, there are no rigorous, first-principle methods to derive the spectrum and properties of the hadrons from the QCD Lagrangian, except for lattice QCD simulations that are not yet able to cope with all aspects of complex and short-lived states. Instead, a variety of “QCD inspired” phenomenological models have been proposed. Common features of these models are predictions for the existence of hadrons with substructures that are more complex than the standard quark-antiquark mesons and the three-quark baryons of the original quark model that provides a concise description of most of the low-mass hadrons. Recently, an assortment of candidates for nonstandard multiquark mesons, meson-gluon hybrids, and pentaquark baryons that contain heavy (charm or bottom) quarks has been discovered. Here the experimental evidence for these states is reviewed and some general comparisons of their measured properties with standard quark model expectations and predictions of various models for nonstandard hadrons are made. The conclusion is that the spectroscopy of all but the simplest hadrons is not yet understood.
The Electromagnetic Counterpart of the Binary Neutron Star Merger LIGO/Virgo GW170817. V. Rising X-Ray Emission from an Off-axis Jet

We report the discovery of rising X-ray emission from the binary neutron star merger event GW170817. This is the first detection of X-ray emission from a gravitational-wave (GW) source. Observations acquired with the Chandra X-ray Observatory (CXO) at t ≈ 2.3 days post-merger reveal no significant emission, with L x ≲ 3.2 × 10 38 erg s − 1 (isotropic-equivalent). Continued monitoring revealed the presence of an X-ray source that brightened with time, reaching L x ≈ 9 × 10 38 erg s − 1 at ≈ 15.1 days post-merger. We interpret these findings in the context of isotropic and collimated relativistic outflows (both on- and off-axis). We find that the broadband X-ray to radio observations are consistent with emission from a relativistic jet with kinetic energy E k ∼ 10 49 − 50 erg , viewed off-axis with θ obs ∼ 20 ° – 40 ° . Our models favor a circumbinary density n ∼ 10 − 4 – 10 − 2 cm − 3 , depending on the value of the microphysical parameter ϵ B = 10 − 4 – 10 − 2 . A central-engine origin of the X-ray emission is unlikely. Future X-ray observations at t ≳ 100 days, when the target will be observable again with the CXO, will provide additional constraints to solve the model degeneracies and test our predictions. Our inferences on θ obs are testable with GW information on GW170817 from advanced LIGO/Virgo on the binary inclination.
Hubble Space Telescope Observations of the Cometary Blue Compact Dwarf Galaxy UGC 4483: A Relatively Young Galaxy?

We present V and I photometry of the resolved stars in the cometary blue compact dwarf galaxy UGC 4483 using Hubble Space Telescope Wide Field Planetary Camera 2 images. The resulting I versus V-I color-magnitude diagram (CMD) reaches limiting magnitudes V = 27.5 mag and I = 26.5 mag for photometric errors less than 0.2 mag. It reveals not only a young stellar population of blue main-sequence stars and blue and red supergiants but also an older evolved population of red giant and asymptotic giant branch stars. The measured magnitude I = 23.65 ± 0.10 mag of the red giant branch tip results in a distance modulus m - M = 27.63 ± 0.12, corresponding to a distance of 3.4 ± 0.2 Mpc. The youngest stars are associated with the bright H II region at the northern tip of the galaxy. The population of older stars is found throughout the low surface brightness body of the galaxy and is considerably more spread out than the young stellar population, suggesting stellar diffusion. The most striking characteristics of the CMD of UGC 4483 are the very blue colors of the red giant stars and the high luminosity of the asymptotic giant branch stars. Both of these characteristics are consistent with either (1) a very low metallicity ([Fe/H] = -2.4, like the most metal-deficient globular clusters) and an old age of 10 Gyr or (2) a higher metallicity ([Fe/H] = -1.4, as derived from the ionized gas emission lines) and a relatively young age of the oldest stellar population in UGC 4483, not exceeding ~2 Gyr. Thus, our data do not exclude the possibility that UGC 4483 is a relatively young galaxy having formed its first stars only ~2 Gyr ago.
Recent results of the DANSS experiment

We present new results of the DANSS experiment on the searches for sterile neutrinos. They are based on 2.1 million of inverse beta decay events collected at 10.7, 11.7 and 12.7 meters from the reactor core of the 3.1 GW Kalinin Nuclear Power Plant in Russia. This data sample is 2.5 times larger than the data sample in the previous DANSS publication. The search for the sterile neutrinos is performed using the ratio of $\bar\nu_e$ spectra at two distances. This method is very robust against systematic uncertainties in the $\bar\nu_e$ spectrum and the detector efficiency. We do not see any statistically significant sign for the $\bar\nu_e$ oscillations. This allows us to exclude further a large and interesting part of the sterile neutrino parameter space. All results are preliminary.
Three-dimensional Hydrodynamic Simulations of Relativistic Extragalactic Jets

We describe a new numerical three-dimensional relativistic hydrodynamic code and present the results of three validation tests. A comparison of an axisymmetric jet simulation using the three-dimensional code, with corresponding results from an earlier two-dimensional code, reveal that (1) the enforcement of axisymmetry in the two-dimensional case had no significant influence on the global morphology and dynamics and (2) although three-dimensional studies typically have lower resolution than those using two dimensions, limiting their ability to fully capture internal jet structure, such three-dimensional studies can provide a reliable model of global morphology and dynamics. The three-dimensional code has been used to study the deflection and precession of relativistic flows. We find that even quite fast jets (γ ~ 10) can be significantly influenced by impinging on an oblique density gradient, exhibiting a rotation of the Mach disk in the jet's head. The flow is bent via a potentially strong, oblique internal shock that arises owing to asymmetric perturbation of the flow by its cocoon. In extreme cases this cocoon can form a marginally relativistic flow orthogonal to the jet, leading to large-scale dynamics quite unlike that normally associated with astrophysical jets. Exploration of a γ = 5 flow subject to a large amplitude precession (semiangle 11.°25) shows that it retains its integrity, with modest reduction in Lorentz factor and momentum flux, for almost 50 jet radii, but thereafter the collimated flow is disrupted. The flow is approximately ballistic, with velocity vectors not aligned with the local jet "wall. " However, sufficiently large changes in flow direction take place within the jet that for observers close to the jet axis, significant changes in Doppler boost would be evident along the flow. We consider simple estimators of the flow emissivity in each case and conclude that (1) while the oblique internal shocks that mediate a small change in the direction of the deflected flows have little impact on the global dynamics, significantly enhanced flow emission (by a factor of 2-3) may be associated with such regions and (2) the convolution of rest-frame emissivity and Doppler boost in the case of the precessed jet invariably leads to a core-jet-like structure but that intensity fluctuations in the jet cannot be uniquely associated with either change in internal conditions or Doppler boost alone but, in general, are a combination of both factors.
Discovery of Kilohertz Quasi-periodic Oscillations and Shifted Frequency Correlations in the Accreting Millisecond Pulsar XTE J1807–294

We report the discovery of twin kilohertz quasi-periodic oscillations (kHz QPOs) in the X-ray flux of XTE J1807-294, the fourth accreting millisecond pulsar (AMP). This is the second AMP exhibiting twin kHz QPOs. In contrast to the first case, SAX J1808.4-3658, the frequency separation Δν between these kHz QPOs is consistent with the pulse frequency (190.6 Hz), not with half that value, confirming for the first time from pulsation measurements the inference, based on burst oscillations, that "slow rotators" (spin frequency less than 400 Hz) have Δν approximately equal to the spin frequency. While the QPOs move in frequency together over a range of more than 200 Hz, Δν remains constant with an average value of 205 ± 6 Hz. Variability components were found in the 5-130 Hz range, similar to those seen in other LMXBs. The correlations between the QPO and noise frequencies are also similar to those in other sources, but shifted by a factor of 1.59 in kHz QPO frequencies, similar to the factor of 1.45 shift found for SAX J1808.4-3658. Our results argue in favor of a spin-related formation mechanism for twin kHz QPOs and against a spin-related cause of the shift in the frequency correlations.
Shedding New Light on the 3C 273 Jet with the Spitzer Space Telescope

We have performed infrared imaging of the jet of the quasar 3C 273 at wavelengths of 3.6 and 5.8 μm with the Infrared Array Camera (IRAC) on the Spitzer Space Telescope. When combined with the radio, optical, and X-ray measurements, the IRAC photometry of the X-ray-bright jet knots clearly shows that the optical emission is dominated by the high-energy emission component of the jet, not by the radio synchrotron component, as had been assumed to date. The high-energy component, represented by a power law from the optical through X-ray, may be due to a second synchrotron component or to inverse Compton scattering of ambient photons. In the former case, we argue that the acceleration of protons exceeding energies of Ep ~ 1016 eV or possibly even to Ep ~ 1019 eV would be taking place in the jet knots of 3C 273, assuming that the acceleration time is proportional to the particle gyroradius. In contrast, the inverse Compton model, into which highly relativistic Doppler beaming has to be incorporated, requires very low energy electrons of Ee ~ 1 MeV in the jet knots. The present polarization data in the radio and optical would favor the former interpretation in the case of the 3C 273 jet. Sensitive and detailed measurements of optical polarization are important in order to establish the radiation mechanism responsible for the high-energy emission. The present study offers new clues as to the controversial origin of the X-ray emission seen in many quasar jets.
One-particle dispersion and spectral weights in the transverse ising model

The one-particle contribution to the dynamical structure factor is explored for the simple case of the transverse Ising model, using series expansion methods. The critical behavior of the spectral weight is found to conform with the general predictions of Sachdev. For the linear chain, exact results are obtained, and confirmed by correspondence with exactly known results for the correlation functions of the quantum $XY$ model in one dimension. In higher dimensions, series are calculated for the triangular, square, and simple cubic lattices, and numerical estimates for the critical exponents are found to agree with expectations, within errors.
Slow light generation in singlemode er-doped tellurite fibre

The efficient generation of slow light in a singlemode Er-doped tellurite glass fibre, which has a Brillouin gain coefficient about an order of magnitude larger than silica fibre is reported. Pulses of 60 ns width were delayed by 67 ns in a 2 m length of fibre with a pump power of 630 mW. The large Brillouin gain and relatively low loss of tellurite fibre should be useful in the realisation of compact slow light devices operable at a lower pump power.
Three Small Planets Transiting the Bright Young Field Star K2-233

We report the detection of three small transiting planets around the young K3 dwarf K2-233 (2MASS J15215519−2013539) from observations during Campaign 15 of the K2 mission. The star is relatively nearby (d = 69 pc) and bright (V = 10.7 mag, Ks = 8.4 mag), making the planetary system an attractive target for radial velocity follow-up and atmospheric characterization with the James Webb Space Telescope. The inner two planets are hot super-Earths (Rb = 1.40 ± 0.06 , Rc = 1.34 ± 0.08 ), while the outer planet is a warm sub-Neptune (Rd = 2.6 ± 0.1 ). We estimate the stellar age to be Myr based on rotation, activity, and kinematic indicators. The K2-233 system is particularly interesting given recent evidence for inflated radii in planets around similarly aged stars, a trend potentially related to photo-evaporation, core cooling, or both mechanisms.
Beyond Perturbation: Introduction to the Homotopy Analysis Method

PART I BASIC IDEAS Introduction Illustrative Description Systematic Description Relations to Some Previous Analytic Methods Advantages, Limitations, and Open Questions PART II APPLICATIONS Simple Bifurcation of a Nonlinear Problem Multiple Solutions of a Nonlinear Problem Nonlinear Eigenvalue Problem Thomas-Fermi Atom Model Volterra's Population Model Free Oscillation Systems with Odd Nonlinearity Free Oscillation Systems with Quadratic Nonlinearity Limit Cycle in a Multidimensional System Blasius' viscous Flow Boundary-layer Flow with Exponential Property Boundary-layer Flow with Algebraic Property Von Karman Swirling Flow Nonlinear Progressive Waves in Deep Water BIBLIOGRAPHY INDEX