Miracle-dz/UniFAR-FTUs huggingface dataset:
When are extremely metal-deficient galaxies extremely metal-deficient?

Extremely metal-deficient (XMD) galaxies, by definition, have oxygen abundances ≤1/10 solar, and form a very small fraction of the local gas-rich, star-forming dwarf galaxy population. We examine their positions in the luminosity–metallicity (L–Z) and mass–metallicity (M–Z) planes, with respect to the L–Z and M–Z relations of other gas-rich, star-forming dwarf galaxies, viz., blue compact galaxies (BCGs) and dwarf irregular (dI) galaxies. We find that while the metallicities of some low-luminosity XMD galaxies are consistent with those expected from the L–Z relation, other XMD galaxies are deviant, and more so as the luminosity and/or metal-deficiency increases. We determine the 95 per cent confidence interval around the L–Z relation for BCGs, and find that its lower boundary is given by 12 + log (O/H) =− 0.177 MB+ 4.87. We suggest that a galaxy should be regarded as XMD, in a statistically significant manner, only if it lies below this boundary in the L–Z plane. Of our sample of XMD galaxies, we find that more than half are XMD by this criterion, and in fact, nine of the galaxies lie below the 99.5 per cent confidence interval about the L–Z relation. We also determine the gas mass fractions and chemical yields of galaxies in all three samples. We find that the effective chemical yield increases with increasing baryonic mass, consistent with what is expected if outflows of metal-enriched gas are important in determining the effective yield. XMD galaxies have lower effective yield than BCG/dI galaxies of similar baryonic mass. This suggests that some process, peculiar to XMD galaxies, has resulted in their low measured metallicities. Motivated by the fact that interactions are common in XMD galaxies, we suggest that improved (tidally driven) mixing of the interstellar media (ISM) in XMD galaxies leads to a lowering of both, the measured metallicity and the calculated effective yield. In isolated dwarf galaxies, the outer parts of the stellar envelope probably do not participate in the star formation, but are still generally included in the calculation of effective yield. This results in an overestimate of the effective yield. We suggest that XMD galaxies are deviant from the L–Z relation because of a combination of being gas rich (i.e. having processed less gas into stars) and having more uniform mixing of metals in their ISM.
The nature of the X-ray transient MAXI J0556−332

Phase-resolved spectroscopy of the newly discovered X-ray transient MAXIJ0556-332 has revealed the presence of narrow emission lines in the Bowen region that most likely arise on the surface of the mass donor star in this low-mass X-ray binary. A period search of the radial velocities of these lines provides two candidate orbital periods (16.43 ± 0.12 and 9.754 ± 0.048h), which differ from any potential X-ray periods reported. Assuming that MAXIJ0556-332 is a relatively high-inclination system that harbours a precessing accretion disc in order to explain its X-ray properties, it is only possible to obtain a consistent set of system parameters for the longer period. These assumptions imply a mass ratio of q≃ 0.45, a radial velocity semi-amplitude of the secondary of K 2≃ 190kms -1 and a compact object mass of the order of the canonical neutron star mass, making a black hole nature for MAXIJ0556-332 unlikely. We also report the presence of strong Niii emission lines in the spectrum, thereby inferring a high N/O abundance. Finally, we note that the strength of all emission lines shows a continuing decay over the ≃1 month of our observations.
A measurement of the muon neutrino charged current quasielastic interaction and a test of Lorentz violation with the MiniBooNE experiment

The Mini-Booster neutrino experiment (MiniBooNE) at Fermi National Accelerator Laboratory (Fermilab) is designed to search for {nu}{sub {mu}} {yields} {nu}{sub e} appearance neutrino oscillations. Muon neutrino charged-current quasi-elastic (CCQE) interactions ({nu}{sub {mu}} + n {yields} {mu} + p) make up roughly 40% of our data sample, and it is used to constrain the background and cross sections for the oscillation analysis. Using high-statistics MiniBooNE CCQE data, the muon-neutrino CCQE cross section is measured. The nuclear model is tuned precisely using the MiniBooNE data. The measured total cross section is {sigma} = (1.058 {+-} 0.003 (stat) {+-} 0.111 (syst)) x 10{sup -38} cm{sup 2} at the MiniBooNE muon neutrino beam energy (700-800 MeV). {nu}{sub e} appearance candidate data is also used to search for Lorentz violation. Lorentz symmetry is one of the most fundamental symmetries in modern physics. Neutrino oscillations offer a new method to test it. We found that the MiniBooNE result is not well-described using Lorentz violation, however further investigation is required for a more conclusive result.
Bifurcation and stability analysis of a Dual-Active-Bridge dc-dc converter working under non-linear control

The Dual-Active-Bridge dc-dc converter is increasingly used in different fields of power electronics. This converter has different advantages compared to other topologies but can run into its operating range in areas of instability that limit its application. For this reason, the paper develops an accurate discrete large-signal sampled-data model of the controlled converter, then it carries out a stability and bifurcation analysis of the system to determine guidelines to increase the stability region of the controlled system. The control strategy is a discrete non-linear method based on the linearization of Jacobian matrixes. Then the tuning of regulator is a dynamic pole placement implemented using root locus analysis; the assigned poles have been chosen minimizing the 2norm of eigenvalues. This tuning process results in a combination of the pole placement strategy and of the gain scheduling approach, that means both robust and adaptative. Such analysis has been verified by MATLAB simulations. The numerical results show the strong dependence of the stability of the controlled system on the resistance of the output filter capacitor and on the parameters of controller.
MULTI-SCALE ANALYSIS OF MAGNETIC FIELDS IN FILAMENTARY MOLECULAR CLOUDS IN ORION A

New visible and K-band polarization measurements of stars surrounding molecular clouds in Orion A and stars in the Becklin–Neugebauer (BN) vicinity are presented. Our results confirm that magnetic fields located inside the Orion A molecular clouds and in their close neighborhood are spatially connected. On and around the BN object, we measured the angular offsets between the K-band polarization data and available submillimeter (submm) data. We find high values of the polarization degree, PK, and of the optical depth, τK, close to an angular offset position of 90° whereas lower values of PK and τK are observed for smaller angular offsets. We interpret these results as evidence for the presence of various magnetic field components toward lines of sight in the vicinity of BN. On a larger scale, we measured the distribution of angular offsets between available H-band polarization data and the same submm data set. Here we find an increase of 〈PH〉 with angular offset, which we interpret as a rotation of the magnetic field by ≲ 60°. This trend generalizes previous results on small scales toward and around lines of sight to BN and is consistent with a twist of the magnetic field on a larger scale toward OMC-1. A comparison of our results with several other studies suggests that a two-component magnetic field, perhaps helical, could be wrapping the OMC-1 filament.
Contamination Evaluation and Source Analysis of Heavy Metals in Karst Soil Using UNMIX Model and Pb-Cd Isotopes

Karst terrain is the typical area covered with a high background of heavy metals under geochemical anomaly. This research explored the accumulation of geochemical elements and soil sources in karst terrain from rock and soil exposed in carbonate areas. The comprehensive ecological risk and enrichment of heavy metals from parent rock weathered to soil was investigated in 11 formations in the carbonate and clastic areas of the Weining and Hezhang counties in northwest Guizhou. The single factor pollution index, geoaccumulation index, and the potential risk coefficient were used to assess the environmental risk. The results revealed that the heavy metals in an overall geologically high background level of soil in northwest Guizhou is at a slight risk level. However, except for Cd, the heavy metals did not exceed the standard pollution reference. Moreover, the UNMIX model and Cd and Pb isotopes were used to analyze the source of heavy metals, comprising of cadmium (Cd), arsenic (As), lead (Pb), chromium (Cr), copper (Cu), nickel (Ni), and zinc (Zn), and the geochemical elements of silicon (Si), aluminum (Al), iron (Fe), magnesium (Mg), and calcium (Ca). The study showed that most elements in the soil carbonate area exceed the national standard, and the heavy metals in the soil showed a strong enrichment, while the major elements Si and Mg display strong loss. Heavy metal concentrations in soil in the carbonate area were higher than in the clastic area. Geological sources and atmospheric deposition were the main contributors to heavy metal concentrations in both carbonate and clastic areas, and their concentrations differ according to soils developing in different formations.
White dwarf main-sequence binaries from SDSS DR 8: unveiling the cool white dwarf population

The spectroscopic catalogue of white dwarf main-sequence (WDMS) binaries from the Sloan Digital Sky Survey (SDSS) is the largest and most homogeneous sample of compact binary stars currently known. However, because of selection effects, the current sample is strongly biased against systems containing cool white dwarfs and/or early-type companions, which are predicted to dominate the intrinsic population. In this study, we present colour selection criteria that combines optical (ugriz DR 8 SDSS) plus infrared (yjhk DR 9 UKIRT Infrared Sky Survey, JHK Two Micron All Sky Survey and/or w1w2 Wide-Field Infrared Survey Explorer) magnitudes to select 3419 photometric candidates of harbouring cool white dwarfs and/or dominant (M dwarf) companions. We demonstrate that 84 per cent of our selected candidates are very likely genuine WDMS binaries, and that the white dwarf effective temperatures and secondary star spectral types of 71 per cent of our selected sources are expected to be below ≲10 000-15 000 K, and concentrated at M2-3, respectively. We also present an updated version of the spectroscopic SDSS WDMS binary catalogue, which incorporates 47 new systems from SDSS DR 8. The bulk of the DR 8 spectroscopy is made up of mainsequence stars and red giants that were targeted as part of the Sloan Extension for Galactic Understanding and Exploration (SEGUE) Survey, therefore the number of new spectroscopic WDMS binaries in DR 8 is very small compared to previous SDSS data releases. Despite their low number, DR 8 WDMS binaries are found to be dominated by systems containing cool white dwarfs and therefore represent an important addition to the spectroscopic sample. The updated SDSS DR 8 spectroscopic catalogue of WDMS binaries consists of 2316 systems. We compare our updated catalogue with recently published lists of WDMS binaries and conclude that it currently represents the largest, most homogeneous and cleanest sample of spectroscopic WDMS binaries from SDSS.
Ion-molecule reactions involving HCO+ and N2H+: Isotopologue equilibria from new theoretical calculations and consequences for interstellar isotope fractionation

Aims. We revisit with new augmented accuracy the theoretical dynamics of basic isotope exchange reactions involved in the 12 C/ 13 C, 16 O/ 18 O, and 14 N/ 15 N balance because these reactions have already been studied experimentally in great detail. Methods. Electronic structure methods were employed to explore potential energy surfaces, full-dimensional rovibrational calculations to compute rovibrational energy levels that are numerically exact, and chemical network models to estimate the abundance ratios under interstellar conditions. Results. New exothermicities, derived for HCO + reacting with CO, provide rate coefficients markedly different from previous theoretical values in particular at low temperatures, resulting in new abundance ratios relevant for carbon chemistry networks. In concrete terms, we obtain a reduction in the abundance of H 12 C 18 O + and an increase in the abundance of H 13 C 16 O + and D 13 C 16 O + . I n all studied cases, the reaction of the ion with a neutral polarizable molecule proceeds through the intermediate proton-bound complex found to be very stable. For the complexes OCH + ··· CO, OCH + ·· ·OC, COHOC + ,N 2 ··· HCO + ,N 2H + ··· OC, and N2HN + ,w e also calculated vibrational frequencies and dissociation energies. Conclusions. The linear proton-bound complexes possess sizeable dipole moments, which may facilitate their detection.
Far-infrared and dust properties of present-day galaxies in the EAGLE simulations

The Evolution and Assembly of GaLaxies and their Environments (EAGLE) cosmological simulations reproduce the observed galaxy stellar mass function and many galaxy properties. In this work, we study the dust-related properties of present-day EAGLE galaxies through mock observations in the far-infrared and submm wavelength ranges obtained with the 3D dust radiative transfer code SKIRT. To prepare an EAGLE galaxy for radiative transfer processing, we derive a diffuse dust distribution from the gas particles and we re-sample the star-forming gas particles and the youngest star particles into star-forming regions that are assigned dedicated emission templates. We select a set of redshift-zero EAGLE galaxies that matches the K-band luminosity distribution of the galaxies in the Herschel Reference Survey (HRS), a volumelimited sample of about 300 normal galaxies in the Local Universe. We find overall agreement of the EAGLE dust scaling relations with those observed in the HRS, such as the dust-tostellar mass ratio versus stellar mass and versus NUV-r colour relations. A discrepancy in the f(250)/f(350) versus f(350)/f(500) submm colour-colour relation implies that part of the simulated dust is insufficiently heated, likely because of limitations in our sub-grid model for star-forming regions. We also investigate the effect of adjusting the metal-to-dust ratio and the covering factor of the photodissociation regions surrounding the star-forming cores. We are able to constrain the important dust-related parameters in our method, informing the calculation of dust attenuation for EAGLE galaxies in the UV and optical domain.
PHIBSS: MOLECULAR GAS CONTENT AND SCALING RELATIONS IN z ∼ 1–3 MASSIVE, MAIN-SEQUENCE STAR-FORMING GALAXIES

We present PHIBSS, the IRAM Plateau de Bure high-z blue sequence CO 3–2 survey of the molecular gas properties in massive, main-sequence star-forming galaxies (SFGs) near the cosmic star formation peak. PHIBSS provides 52 CO detections in two redshift slices at z ∼ 1.2 and 2.2, with log(M*(M☉)) ⩾ 10.4 and log(SFR(M☉/yr)) ⩾ 1.5. Including a correction for the incomplete coverage of the M*–SFR plane, and adopting a “Galactic” value for the CO–H2 conversion factor, we infer average gas fractions of ∼0.33 at z ∼ 1.2 and ∼0.47 at z ∼ 2.2. Gas fractions drop with stellar mass, in agreement with cosmological simulations including strong star formation feedback. Most of the z ∼ 1–3 SFGs are rotationally supported turbulent disks. The sizes of CO and UV/optical emission are comparable. The molecular-gas–star-formation relation for the z = 1–3 SFGs is near-linear, with a ∼0.7 Gyr gas depletion timescale; changes in depletion time are only a secondary effect. Since this timescale is much less than the Hubble time in all SFGs between z ∼ 0 and 2, fresh gas must be supplied with a fairly high duty cycle over several billion years. At given z and M*, gas fractions correlate strongly with the specific star formation rate (sSFR). The variation of sSFR between z ∼ 0 and 3 is mainly controlled by the fraction of baryonic mass that resides in cold gas.
METALLICITIES OF EMISSION-LINE GALAXIES FROM HST ACS PEARS AND HST WFC3 ERS GRISM SPECTROSCOPY AT 0.6 < z < 2.4

Galaxies selected on the basis of their emission-line strength show low metallicities, regardless of their redshifts. We conclude this from a sample of faint galaxies at redshifts between 0.6 < z < 2.4, selected by their prominent emission lines in low-resolution grism spectra in the optical with the Advanced Camera for Surveys on the Hubble Space Telescope and in the near-infrared using Wide-Field Camera 3. Using a sample of 11 emission-line galaxies at 0.6 < z < 2.4 with luminosities of −22 ≲ MB ≲ −19 which have [O ii], Hβ, and [O iii] line flux measurements from the combination of two grism spectral surveys, we use the R23 method to derive the gas-phase oxygen abundances: 7.5 < 12 + log (O/H) < 8.5. The galaxy stellar masses are derived using Bayesian-based Markov Chain Monte Carlo (πMC2) fitting of their spectral energy distribution, and span the mass range 8.1 < log (M*/M☉) < 10.1. These galaxies show mass–metallicity (M–Z) and luminosity–metallicity (L–Z) relations, which are offset by −0.6 dex in metallicity at given absolute magnitude and stellar mass relative to the local Sloan Digital Sky Survey galaxies, as well as continuum-selected DEEP2 samples at similar redshifts. The emission-line-selected galaxies most resemble the local “green peas” galaxies and Lyα galaxies at z ≃ 0.3 and z ≃ 2.3 in the M–Z and L–Z relations and their morphologies. The G − M20 morphology analysis shows that 10 out of 11 show disturbed morphology, even as the star-forming regions are compact. These galaxies may be intrinsically metal poor, being at early stages of formation, or the low metallicities may be due to gas infall and accretion due to mergers.
Magneto-rotational and thermal evolution of young neutron stars

After a brief review of population synthesis of close-by cooling neutron stars, I focus on the interpretation of dichotomy of spin periods of near-by coolers. The existence of two well separated groups -- short period ($\sim$0.1-0.3 s) radio pulsars and long period ($\sim$3-10 s) radio quiet sources, aka the Magnificent seven, -- can not be easily explained in unified models developed recently (Popov et al. 2010, Gull{\'o}n et al. 2014). I speculate that the most natural solution of the problem can be in bimodal initial magnetic field distribution related to the existence of an additional mechanism of field generation in magnetars.
X-ray emission from RX J1720.1+2638 and Abell 267: a comparison between a fossil and a non-fossil system

We present the XMM-Newton X-ray analysis of RXJ1720.1+2638 and Abell267, a non-fossil and a fossil system, respectively. The whole spectrum of both objects can be explained by thermal emission. The luminosities found for RXJ1720.1+2638 and Abell267 in the 2-10 keV band are 6.20^{+0.04}_{-0.02}\times10^{44} and 3.90^{+0.10}_{-0.11}\times10^{44} cgs, respectively. The radial profiles show a cool core nature for the non-fossil system RXJ1720.1+2638, while Abell267 shows a constant behaviour of temperature with radius. Metallicity profiles have also been produced, but no evidence of any gradient was detected due to the large uncertainties in the determination of this parameter. Finally, density and mass profiles were also produced allowing to derive M_500 for RXJ1720.1+2638 and Abell267. The masses obtained are high, in the range of (5-7)10^{14}\,M_{\odot}. The X-ray properties obtained for both systems are not always in good agreement with what is expected: cool cores are expected for fossil systems, as Abell267, considering them as and relaxed systems. However, the decrement of the temperature in Abell267 could start at lower radii. Also the presence of a recent merger in Abell267, already suggested in the literature, could have increased the central temperature. The non-fossil system RXJ1720.1+2638 actually exhibits a cool core profile, but also evidence of a recent merger has been reported.
Magnitude and size evolution of bulgeless galaxies

We examine the magnitude and size evolution of bulgeless (discs with no-bulge or pseudo-bulge) galaxies up to z~0.9 in rest-frame B-band. Their evolution is compared to that of normal-discs (discs with classical-bulge). The study is done for luminous sources (M_B<=-20) in two equal-volume redshift-bins (0.4<=z<0.77 and 0.77<=z<1.0) and a local range (0.02<=z<0.05). The mean surface-brightness, from z_{mean}=0.89 to z_{mean}=0.04, shows a dimming of 0.79 mag for bulgeless galaxies and 1.16 mag for normal-discs. The characteristic magnitude, M_B^*, shows an increase of 0.55-mag for bulgeless galaxies and 0.95-mag for normal-discs. Both dimming and faintness observed since z~0.9 are more pronounced for the normal-discs by ~0.4-mag. The size-distribution is log-normal and both bulgeless and normal-discs show a slight increase in the mean value from z_{mean}=0.89 to z_{mean}=0.04. The proportion of bulgeless galaxies in the full disc sample undergoes a considerable decline with decrease in redshift. This along with the larger dimming and faintness seen for normal-discs suggests that some fraction of the bulgeless sources switch to the normal-disc morphology with time. To ascertain the validity of studying morphology in the optical, the properties of the galaxies observed in both rest-frame B and I-band are compared. The common sample is more luminous in the I-band but the sizes are larger in the B-band for more than 74 % of the sources. The variation in the sersic-index values of the galaxies in the two rest-bands is minor enough to have any affect on the morphological classification.
Planar rook algebra with colors and Pascal's simplex

We define $P_{n,c}$ to be the set of all diagrams consisting of two rows of $n$ vertices with edges, each colored with an element in a set of $c$ possible colors, connecting vertices in different rows. Each vertex can have at most one edge incident to it, and no edges of the same color can cross. In this paper, we find a complete set of irreducible representations of $\C P_{n,c}$. We show that the Bratteli diagram of $\C P_{0,c} \subseteq \C P_{1,c} \subseteq \C P_{2,c} \subseteq. $ is Pascal's $(c+1)$-simplex, and use this to provide an alternative proof of the well-known recursive formula for multinomial coefficients.
Nonflow contribution to Dihadron Azimuthal Correlations in 200 GeV/c Au+Au Collisions

Dihadron azimuthal correlations in 200 GeV/c Au+Au have been simulated by a multi-phase transport (AMPT) model. Contribution from jet-medium interaction to correlation function is obtained by subtracting the combined harmonic flow background from the raw dihadron correlation function. Signals in centralities of 0-10%, 20-40% and 50-80% are compared in three associated transverse momentum ($p_{T}^{assoc}$) bins: 0.2-0.8 GeV/c, 0.8-1.4 GeV/c and 1.4-2.0 GeV/c. An obvious medium modification impact can be seen from the signal shape change and relative jet contribution in the above events, which shows different behaviors between central and peripheral events, and among different $p_{T}^{assoc}$ ranges in central events. More detailed $p_{T}^{assoc}$ dependence of the derived nonflow contribution is studied in central 0-10% events, in which a strong $p_{T}^{assoc}$ dependence of RMS width is observed. We also calculated that relative jet contributions in peripheral and central collisions in the above mentioned cases.