Miracle-dz/UniFAR-FTUs huggingface dataset:
Keeping the Universe ionized: photoheating and the clumping factor of the high-redshift intergalactic medium

The critical star formation rate (SFR) density required to keep the intergalactic hydro- gen ionized depends crucially on the average rate of recombinations in the intergalac- tic medium (IGM). This rate is proportional to the clumping factor C ≡� ρ 2� IGM/�ρ b� 2 , where ρb and �ρ bare the local and cosmic mean baryon density, respectively, and the brackets �� IGM indicate spatial averaging over the recombining gas in the IGM. We per- form a suite of cosmological smoothed particle hydrodynamic simulations that include ra- diative cooling to calculate the volume-weighted clumping factor of the IGM at redshifts z ≥ 6. We focus on the effect of photoionization heating by a uniform ultraviolet background and find that photoheating strongly reduces the clumping factor because the increased pressure support smoothes out small-scale density fluctuations. Photoionization heating is often said to provide a negative feedback on the re-ionization of the IGM because it suppresses the cosmic SFR by boiling the gas out of low-mass haloes. However, because of the reduction of the clumping factor it also makes it easier to keep the IGM ionized. Photoheating therefore also provides a positive feedback which, while known to exist, has received much less attention. We demonstrate that this positive feedback is in fact very strong. Using conservative assumptions, we find that if the IGM was reheated at z 9, the observed population of star-forming galaxies at z ≈ 6 may be sufficient to keep the IGM ionized, provided that the fraction of ionizing photons that escape the star-forming regions to ionize the IGM is larger than ∼0.2.
A study on the universality and linearity of the Leavitt law in the LMC and SMC galaxies

The universality and linearity of the Leavitt law are hypotheses commonly adopted in studies of galaxy distances using Cepheid variables as standard candles. In order to test these hypotheses, we obtain slopes of the Leavitt law using linear regressions of fundamental-mode Cepheids observed by the optical gravitational lensing experiment project in the Magellanic Clouds. We find that the slopes in VI bands and in the Wesenheit index behave exponentially, indicating non-linearity. We also find that the slopes obtained using long-period Cepheids can be considered as universal in the VI bands, but not in the Wesenheit index.
Formation of globular clusters with multiple stellar populations from massive gas clumps in high-z gas-rich dwarf galaxies

Context. One of the currently favored scenarios for the formation of globular clusters (GCs) with multiple stellar populations is that an initial massive stellar system forms (“first generation”, FG), subsequently giving rise to gaseous ejecta which is converted into a second-generation (SG) of stars to form a GC. How such GCs with such FG and SG populations form and evolve, however, remains unclear. Aims. We therefore investigate, for the first time, the sequential formation processes of both FG and SG stars from star-forming massive gas clumps in gas-rich dwarf disk galaxies. Methods. We adopt a novel approach to resolve the two-stage formation of GCs in hydrodynamical simulations of dwarf galaxies. In the new simulations, new gas particles that are much less massive than their parent star particle are generated around each new star particle when the new star enters into the asymptotic giant branch (AGB) phase. Furthermore, much finer maximum time step width (~105 yr) and smaller softening length (~2 pc) are adopted for such AGB gas particles to properly resolve the ejection of gas from AGB stars and AGB feedback effects. Therefore, secondary star formation from AGB ejecta can be properly investigated in galaxy-scale simulations. Results. An FG stellar system can first form from a massive gas clump developing due to gravitational instability within its host gas-rich dwarf galaxy. Initially the FG stellar system is not a single massive cluster, but instead is composed of several irregular stellar clumps (or filaments) with a total mass larger than 106 M⊙. While the FG system is dynamically relaxing, gaseous ejecta from AGB stars can be gravitationally trapped by the FG system and subsequently converted into new stars to form a compact SG stellar system within the FG system. Interestingly, about 40% of AGB ejecta is from stars that do not belong to the FG system (“external gas accretion”). FG and SG stellar systems have different amplitudes of internal rotation and V∕σ. The mass-density (MSG−ρSG) relation for SG stellar systems can be approximated as ρSG ∝ MSG1.5. There can be a threshold total mass of GC host galaxies (Mth = [5 − 23] × 109 M⊙) beyond which the formation of GCs with compact SG stellar systems is possible. Both the initial baryonic mass fraction and the gas mass fraction in dwarfs are crucial parameters that determine whether or not GCs can contain multiple stellar populations. GCs with compact SG stellar systems are more likely to form in dwarf disks with larger gas mass fractions and higher surface mass densities. Formation of binary GCs with SGs and the subsequent GC merging are clearly seen in some models. The derived external gas-accretion process in FG systems initially consisting of stellar clumps will need to be investigated further in more sophisticated simulations.
PLANETARY CORE FORMATION WITH COLLISIONAL FRAGMENTATION AND ATMOSPHERE TO FORM GAS GIANT PLANETS

Massive planetary cores (∼10 Earth masses) trigger rapid gas accretion to form gas giant planets such as Jupiter and Saturn. We investigate the core growth and the possibilities for cores to reach such a critical core mass. At the late stage, planetary cores grow through collisions with small planetesimals. Collisional fragmentation of planetesimals, which is induced by gravitational interaction with planetary cores, reduces the amount of planetesimals surrounding them, and thus the final core masses. Starting from small planetesimals that the fragmentation rapidly removes, less massive cores are formed. However, planetary cores acquire atmospheres that enlarge their collisional cross section before rapid gas accretion. Once planetary cores exceed about Mars mass, atmospheres significantly accelerate the growth of cores. We show that, taking into account the effects of fragmentation and atmosphere, initially large planetesimals enable formation of sufficiently massive cores. On the other hand, because the growth of cores is slow for large planetesimals, a massive disk is necessary for cores to grow enough within a disk lifetime. If the disk with 100 km sized initial planetesimals is 10 times as massive as the minimum mass solar nebula, planetary cores can exceed 10 Earth masses in the Jovian planet region (>5 AU).
The s-Process in Low Metallicity Stars. II. Interpretation of High-Resolution Spectroscopic Observations with AGB models

High-resolution spectroscopic observations of a hundred metal-poor Carbon and s-rich stars (CEMP-s) collected from the literature are compared with the theoretical nucleosynthesis models of asymptotic giant branch (AGB) presented in Paper I (M = 1.3, 1.4, 1.5, 2 Msun, -3.6 < [Fe/H] < -1.5). The s-process enhancement detected in these objects is associated to binary systems: the more massive companion evolved faster through the thermally pulsing AGB phase (TP-AGB), synthesising in the inner He-intershell the s-elements, which are partly dredged-up to the surface during the third dredge-up (TDU) episode. The secondary observed low mass companion became CEMP-s by mass transfer of C and s-rich material from the primary AGB. We analyse the light elements as C, N, O, Na and Mg, as well as the two s-process indicators, [hs/ls] (where ls = is the the light-s peak at N = 50 and hs = the heavy-s peak at N = 82), and [Pb/hs]. We distinguish between CEMP-s with high s-process enhancement, [hs/Fe] > 1.5 (CEMP-sII), and mild s-process enhanced stars, [hs/Fe] < 1.5 (CEMP-sI). To interpret the observations, . Detailed analyses for individual stars will be provided in Paper III.
THE EFFECT OF MISWAK & ITS PROTOCOL OF PLACEMENT, ON THE STRUCTURE, MINERAL CONTENT OF CHEMICAL AND LASER ASSISTED BLEACHED WHITE SPOT

Aim: The aim of the present study was to evaluate the change in enamel structure and mineral content of artificially created white spot lesion treated either by chemical or Laser assisted bleaching preceded or followed by miswak application Materials and Methods : Miswak freezed dried extract was prepared from freshly cut chewing sticks. Ten human sound premolar teeth freshly extracted due to orthodontic causes were divided into two halves in a mesio-distal direction two halves. A total of twenty specimens were obtained and undergone baseline surface scanning by EDX/SEM. White spot lesion is first artificially created by immersing specimens in demineralizing solution for five days. Another enamel surface scanning by EDX/SEM were done for all specimens after demineralization. The specimens were either undergone chemical bleaching using 36% hydrogen peroxide alone or Laser assisted bleaching that is performed by same concentration hydrogen peroxide activated by diode low energy Laser 980 nm. Miswak is either placed on white spot lesion before bleaching or after bleaching. A final EDX/ SEM is done after treatment. Results: For chemical bleaching group, placement of miswak on wsls followed by chemical bleaching results in enhanced remineralization with significant increase in calcium and phosphate of bleached enamel. For Laser bleaching group, placing miswak on wsls after laser activated bleaching results in significant increase in phosphate level of bleached enamel in addition to enhanced remineralization. Conclusion : Miswak can remineralize white spot lesion treated with chemical or Laser bleaching technique with proper protocol.
STELLAR POPULATIONS AND STAR FORMATION HISTORY OF THE METAL-POOR DWARF GALAXY DDO 68

We present the star formation history (SFH) of the extremely metal-poor dwarf galaxy DDO 68, based on our photometry with the Advanced Camera for Surveys. With a metallicity of only and a very isolated location, DDO 68 is one of the most metal-poor galaxies known. It has been argued that DDO 68 is a young system that started forming stars only ∼0.15 Gyr ago. Our data provide a deep and uncontaminated optical color–magnitude diagram (CMD) that allows us to disprove this hypothesis since we find a population of at least ∼1 Gyr old stars. The star formation activity has been fairly continuous over all the look-back time. The current rate is quite low, and the highest activity occurred between 10 and 100 Myr ago. The average star formation rate over the whole Hubble time is ≃0.01 M⊙ yr−1, corresponding to a total astrated mass of ≃1.3 × 108 M⊙. Our photometry allows us to infer the distance from the tip of the red giant branch, D = 12.08 ± 0.67 Mpc; however, to let our synthetic CMD reproduce the observed ones, we need a slightly higher distance, D = 12.65 Mpc, or (m − M)0 = 30.51, still inside the errors of the previous determination, and we adopt the latter. DDO 68 shows a very interesting and complex history, with its quite disturbed shape and a long tail, probably due to tidal interactions. The SFH of the tail differs from that of the main body mainly for enhanced activity at recent epochs likely triggered by the interaction.
Effect of different lithium silicate ceramics with variable shades, thickness and curing modes on the degree of conversion of resin cement

Purpose: The bond strength between ceramics and tooth structure is affected by the degree of polymerization of resin cement. This study evaluated the effect of two light curing modes on polymerization of light cured resin cement through three lithium silicate-based ceramics (Lithium disilicate-reinforced glass ceramic (E.max CAD), Zirconia reinforced Lithium Silicate (Celtra Duo). And Zirconia reinforced Lithium Silicate (Vita Suprinity) with two shades (A2 and B1) and two ceramic thickness (0.5 and 1mm). Materials and methods: Two hundred forty ceramic samples (n=240) were divided into three main groups (n=80) according to the material. Each group was subdivided into 2 subgroups (n=40) according to ceramic shade (A2 and B1). Each subgroup was subdivided into 2 divisions (n=20) according to thickness (0.5mm and 1mm). Then each division was subdivided into two subdivisions (n=10) according to light curing method (Continuous and pulsating light curing). Samples cemented and scanned using OMNIC 5.1c software connected to the FTIR unit. Results: The results illustrated that there was no statistical significance difference in degree of conversion between the three ceramic materials. A higher degree of conversion was recorded with B1 ceramic shade than A2 shade. Also, there was a significant effect on the degree of conversion (DC%)
Black hole dynamical evolution in a Lorentz-violating spacetime

We consider the black hole dynamical evolution in the framework of a Lorentz-violating spacetime endowed with a Schwarzchild-like momentum-dependent metric. Large deviations from the Hawking-Bekenstein predictions are obtained, depending on the values of the Lorentz-violating parameter {lambda} introduced. A nontrivial evolution comes out, following mainly from the existence of a nonvanishing minimum mass: for large Lorentz violations, most of the black hole evaporation takes place in the initial stage, which is then followed by a stationary stage (whose duration depends on the value of {lambda}) where the mass does not change appreciably. Furthermore, for the final stage of evolution, our model predicts a sweet slow death of the black hole, whose ''slowness'' again depends on {lambda}, in contrast with the violent final explosion predicted by the standard theory.
The Impact of The Relationship Between Managerial Ability and Earnings Management by Classification Shifting on Transparency of Financial Reporting and Firm Value: An Empirical Evidence from The Saudi Capital Market

This research investigates the impact of interaction between managerial ability (MA, hereafter), and earnings management by classification shifting (EMBCS, hereafter) on financial reporting transparency and firm value. This study examines whether highly competent managers are more likely than other managers to intentionally classification shifting as a means of managing earnings. Furthermore, this study also tests economic consequences associated with the inter-relationship between EMBCS practices and MA. We collected data from 125 non-financial firms listed on the Saudi Capital Market from 2015 to 2019. The results demonstrate that a high MA mitigates EMBCS practices. The results also show that the inter-relationship between EMBCS practices and MA reduces the costs of the agency as an indicator of the transparency of accounting information. Moreover, our findings show that the relationship between EMBCS practices and MA has a positive influence on the value of the firms listed on the Saudi Capital Market.
Low temperature HD+ortho-/para-H2 inelastic scattering of astrophysical interest

State-selected total cross sections and thermal rate coefficients are computed for the HD + ortho-/para-H2 rotational energy transfer collision at low temperatures: 2 K ≲ T ≲ 300 K. A modified H2-H2 potential energy surface (PES) devised by Hinde is used for this pure quantum-mechanical dynamical computation. A comparison of the new results for the HD + ortho-/para-H2 scattering problem and previous calculations computed with the use of other older PESs is presented and discussed.
SOURCE-INTRINSIC NEAR-INFRARED PROPERTIES OF SGR A*: TOTAL INTENSITY MEASUREMENTS

We present a comprehensive data description for Ks-band measurements of Sgr A*. We characterize the statistical properties of the variability of Sgr A* in the near-infrared, which we find to be consistent with a single-state process forming a power-law distribution of the flux density. We discover a linear rms–flux relation for the flux density range up to 12 mJy on a timescale of 24 minutes. This and the power-law flux density distribution implies a phenomenological, formally nonlinear statistical variability model with which we can simulate the observed variability and extrapolate its behavior to higher flux levels and longer timescales. We present reasons why data with our cadence cannot be used to decide on the question whether the power spectral density of the underlying random process shows more structure at timescales between 25 minutes and 100 minutes compared to what is expected from a red-noise random process.
THE VERTICAL X-SHAPED STRUCTURE IN THE MILKY WAY: EVIDENCE FROM A SIMPLE BOXY BULGE MODEL

A vertical X-shaped structure in the Galactic bulge was recently reported. Here, we present evidence of a similar X-shaped structure in the Shen et al. 2010 bar/boxy bulge model that simultaneously matches the stellar kinematics successfully. The X-shaped structure is found in the central region of our bar/boxy bulge model and is qualitatively consistent with the observed one in many aspects. End-to-end separations of the X-shaped structure in the radial and vertical directions are roughly 3 kpc and 1.8 kpc, respectively. The X-shaped structure contains about 7% of light in the boxy bulge region, but it is significant enough to be identified in observations. An X-shaped structure naturally arises in the formation of bar/boxy bulges and is mainly associated with orbits trapped around the vertically extended x1 family. Like the bar in our model, the X-shaped structure tilts away from the Sun–Galactic center line by 20°. The X-shaped structure becomes increasingly symmetric about the disk plane, so the observed symmetry may indicate that it formed at least a few billion years ago. The existence of the vertical X-shaped structure suggests that the formation of the Milky Way bulge is shaped mainly by internal disk dynamical instabilities.
Measurement of Neutrino-Electron Elastic Scattering at NOvA Near Detector

NOvA is a long-baseline accelerator-based neutrino oscillation experiment that is optimized for electron-neutrino appearance measurements. It uses the upgraded NuMI beam from Fermilab and consists of a Far Detector in Ash River, Minnesota and a Near Detector at Fermilab. An accurate prediction of the neutrino flux is key to both oscillation and cross-section measurements. The precisely known neutrino-electron elastic scattering cross section provides an in situ constraint on the absolute flux. This talk discusses the status of the measurement of the rate of neutrino-electron elastic scattering in the NOvA Near Detector.
The incidence of nuclear activity in galaxy pairs with different morphologies (E+E), (E+S) and (S+S)

We analysed 385 galactic spectra from the Sloan Digital Sky Survey Data Release 7 (SDSS-DR7) that belong to the catalog of isolated pairs of galaxies by Karachentsev. The spectra corresponds to physical pairs of galaxies as defined by V $\leq$ 1200 Km/s and a pair separation $\leq$ 100 kpc. We search for the incidence of nuclear activity, both thermal (star-forming) and non-thermal -Active Galactic Nuclei (AGN). After a careful extraction of the nuclear spectra, we use diagnostic diagrams and find that the incidence of AGN activity is 48 \% in the paired galaxies with emission lines and 40\% for the total sample (as compared to $\sim$ 43 \% and 41\% respectively in a sample of isolated galaxies). These results remain after dissecting the effects of morphological type and galactic stellar mass (with only a small, non significant, enhancement of the AGN fraction in pairs of objects). These results suggest that weak interactions are not necessary or sufficient to trigger low-luminosity AGN. Since the fraction of AGN is predominant in early type spiral galaxies, we conclude that the role of a bulge, and a large gas reservoir are both essential for the triggering of nuclear activity. The most striking result is that type 1 galaxies are almost absent from the AGN sample. This result is in conflict with the Unified Model, and suggests that high accretion rates are essential to form the Broad Line Region in active galaxies.
Electronic Structure, Optical and Dielectric Spectroscopy Study of TbMnO3

Spectral ellipsometry studies of the optical functions, first observation of photoluminescence and low frequency dielectric permittivity investigations were performed in ferroelectric - multiferroic TbMnO3 single crystals. The main attention was paid to electronic band structure, nature of the main optical transitions and unusual behavior of the dielectric permittivity in the region of the sharp narrow temperature maximum, associated with ferroelectric phase transition. It was found that magnitude of the permittivity maximum decreases strongly with frequency, whereas position of maximum is frequency independent. Observed features of polarization response can be described satisfactorily in the frame of on the basis of the Landau-Khalatnikov theory for critical relaxation polarization
Long-term stream evolution in tidal disruption events

A large number of tidal disruption event (TDE) candidates have been observed recently, often differing in their observational features. Two classes appear to stand out: X-ray and optical TDEs, the latter featuring lower effective temperatures and luminosities. These differences can be explained if the radiation detected from the two categories of events originates from different locations. In practice, this location is set by the evolution of the debris stream around the black hole and by the energy dissipation associated with it. In this paper, we build an analytical model for the stream evolution, whose dynamics is determined by both magnetic stresses and shocks. Without magnetic stresses, the stream always circularizes. The ratio of the circularization timescale to the initial stream period is $t_{\rm ev}/t_{\rm min} = 8.3 (M_{\rm h}/10^6 M_{\odot})^{-5/3} \beta^{-3}$, where $M_{\rm h}$ is the black hole mass and $\beta$ is the penetration factor. If magnetic stresses are strong, they can lead to the stream ballistic accretion. The boundary between circularization and ballistic accretion corresponds to a critical magnetic stresses efficiency $v_{\rm A}/v_{\rm c} \approx 10^{-1}$, largely independent of $M_{\rm h}$ and $\beta$. However, the main effect of magnetic stresses is to accelerate the stream evolution by strengthening self-crossing shocks. Ballistic accretion therefore necessarily occurs on the stream dynamical timescale. The shock luminosity associated to energy dissipation is sub-Eddington but decays as $t^{-5/3}$ only for a slow stream evolution. Finally, we find that the stream thickness rapidly increases if the stream is unable to cool completely efficiently. A likely outcome is its fast evolution into a thick torus, or even an envelope completely surrounding the black hole.