Miracle-dz/UniFAR-FTUs huggingface dataset:
Star-forming regions and the metallicity gradients in the tidal tails: the case of NGC 92

We present new Gemini/GMOS spectroscopic and archival imaging data of the interacting galaxy NGC 92, which is part of a compact group and displays an extended tidal tail. We have studied the physical properties of 20 star-forming complexes in this system. We found that the star-forming regions located in the tidal tail of NGC 92 have ages younger than similar to 8 Myr, which suggests that these objects were formed in situ. The spectroscopic data reveal that these regions have slightly sub-solar metallicities, suggesting that they were formed from pre-enriched material. Using the oxygen abundances derived for each system, we found that the extended tidal tail of NGC 92 has a flat metallicity distribution. Although this scenario is consistent with N-body simulations of interacting systems, where there is gas mixing triggered by the interaction, archival H alpha Fabry-Perot data cubes of NGC 92 have not shown a velocity gradient along the tail of this galaxy, which under certain assumptions could be interpreted as a lack of gas flow in the tail. Our results suggest that a fraction of the enriched gas that was originally located in the centre of the galaxy was expelled into the tidal tail when the interacting process that formed the tail happened. However, we cannot exclude the scenario in which the star formation in the tail has increased its original oxygen abundance.
Recovering the Star Formation History of IC1613 Dwarf Galaxy Using Evolved Stars

Abstract Determining the star formation history (SFH) is key to understand the formation and evolution of dwarf galaxies. Recovering the SFH in resolved galaxies is mostly based on deep colour–magnitude diagrams (CMDs), which trace the signatures of multiple evolutionary stages of their stellar populations. In distant and unresolved galaxies, the integrated light of the galaxy can be decomposed, albeit made difficult by an age–metallicity degeneracy. Another solution to determine the SFH of resolved galaxies is based on evolved stars; these luminous stars are the most accessible tracers of the underlying stellar populations and can trace the entire SFH. Here we present a novel method based on long period variable (LPV) evolved asymptotic giant branch (AGB) stars and red supergiants (RSGs). We applied this method to reconstruct the SFH for IC1613, an irregular dwarf galaxy at a distance of 750 kpc. Our results provide an independent confirmation that no major episode of star formation occurred in IC1613 over the past 5 Gyr.
Generating quantizing pseudomagnetic fields by bending graphene ribbons

We analyze the mechanical deformations that are required to create uniform pseudomagnetic fields in graphene. It is shown that, if a ribbon is bent in-plane into a circular arc, this can lead to fields exceeding 10 T, which is sufficient for the observation of pseudo-Landau quantization. The arc geometry is simpler than those suggested previously and, in our opinion, has much better chances to be realized experimentally soon. The effects of a scalar potential induced by dilatation in this geometry is shown to be negligible.
Phononic filter effect of rattling phonons in the thermoelectric clathrate Ba8Ge40+xNi6-x.

One of the key requirements for good thermoelectric materials is a low lattice thermal conductivity. Here we present a combined neutron scattering and theoretical investigation of the lattice dynamics in the type I clathrate system Ba-Ge-Ni, which fulfills this requirement. We observe a strong hybridization between phonons of the Ba guest atoms and acoustic phonons of the Ge-Ni host structure over a wide region of the Brillouin zone, which is in contrast with the frequently adopted picture of isolated Ba atoms in Ge-Ni host cages. It occurs without a strong decrease of the acoustic phonon lifetime, which contradicts the usual assumption of strong anharmonic phonon-phonon scattering processes. Within the framework of ab initio density-functional theory calculations we interpret these hybridizations as a series of anticrossings which act as a low-pass filter, preventing the propagation of acoustic phonons. To highlight the effect of such a phononic low-pass filter on the thermal transport, we compute the contribution of acoustic phonons to the thermal conductivity of Ba8Ge40Ni6 and compare it to those of pure Ge and a Ge-46 empty-cage model system.
Properties of meteors with double-peaked light curves

Twenty-one meteors showing double peaked light curves were analysed with observations collected with the Canadian Automated Meteor Observatory tracking system. Each event has orbital information, photometry, and at least one high-resolution observation. Two distinct light curve shapes were found: sudden double peaked curves, and smooth double peaked curves. The sudden peaked curves were produced by objects on asteroidal orbits and mostly showed noticeable fragmentation, while the smooth peaked curves were produced by cometary meteoroids and predominantly showed little to no visible fragmentation. An attempt to model these meteors as single bodies with two chemical components was unsuccessful, implying that fragmentation must be included in meteoroid ablation models.
The fast spin-rotation of a young extra-solar planet

The spin-rotation of a planet arises from the accretion of angular momentum during its formation, but the details of this process are still unclear. In the solar system, the equatorial rotation velocities and spin angular momentum of the planets show a clear trend with mass, except for Mercury and Venus which have significantly spun down since their formation due to tidal interactions. Here we report on near-infrared spectroscopic observations at λ/Δλ=100,000 of the young extra-solar gas giant β Pictoris b. The absorption signal from carbon monoxide in the planet's thermal spectrum is found to be blueshifted with respect to the velocity of the parent star by (-15±1.7) km sec, consistent with a circular orbit. The combined line profile exhibits a rotational broadening of 25±3 km sec, meaning that β Pictoris b spins significantly faster than any planet in the solar system, in line with the extrapolation of the known trend in spin velocity with planet mass.
DISCOVERY OF X-RAY-EMITTING O–Ne–Mg-RICH EJECTA IN THE GALACTIC SUPERNOVA REMNANT PUPPIS A

We report on the discovery of X-ray-emitting O–Ne–Mg-rich ejecta in the middle-aged Galactic O-rich supernova remnant Puppis A with Chandra and XMM-Newton. We use line ratios to identify a low-ionization filament running parallel to the northeastern edge of the remnant that requires super-solar abundances, particularly for O, Ne, and Mg, which we interpret to be from O–Ne–Mg-rich ejecta. Abundance ratios of Ne/O, Mg/O, and Fe/O are measured to be ∼2, ∼2, and <0.3 times the solar values. Our spatially resolved spectral analysis from the northeastern rim to the western rim otherwise reveals sub-solar abundances consistent with those in the interstellar medium. The filament is coincident with several optically emitting O-rich knots with high velocities. If these are physically related, the filament would be a peculiar fragment of ejecta. On the other hand, the morphology of the filament suggests that it may trace ejecta heated by a shock reflected strongly off the dense ambient clouds near the northeastern rim.
Radio frequency electrical transduction of graphene mechanical resonators

We report radio frequency (rf) electrical readout of graphene mechanical resonators. The mechanical motion is actuated and detected directly by using a vector network analyzer, employing a local gate to minimize parasitic capacitance. A resist-free doubly clamped sample with resonant frequency ∼34 MHz, quality factor ∼10 000 at 77 K, and signal-to-background ratio of over 20 dB is demonstrated. In addition to being over two orders of magnitude faster than the electrical rf mixing method, this technique paves the way for use of graphene in rf devices such as filters and oscillators.
Entanglement dynamics in quantum many-body systems

We study entanglement growth in quantum many-body systems and propose a method to experimentally measure it. We show that entanglement growth is related to the spreading of local operators. In ergodic systems, linear spreading of operators results in a universal, linear in time growth of entanglement for initial product states, in contrast to the logarithmic growth of entanglement in many-body localized (MBL) systems. Furthermore, we show that entanglement growth is directly related to the decay of the Loschmidt echo in a composite system comprised of many copies of the original system, subject to a perturbation that reconnects dierent parts of the system. Exponential decay of the Loschmidt echo, characteristic of ergodic systems, implies linear growth of entanglement. Our proposal to experimentally measure entanglement growth uses a quantum switch (two-level system) which controls connections in the composite system. By measuring only the switch’s dynamics, the growth of the R enyi entropies can be extracted. Our work provides a way to directly probe dynamical properties of many-body systems, in particular, allowing for a direct observation of many-body localization.
The faint young Sun problem

For more than four decades, scientists have been trying to find an answer to one of the most fundamental questions in paleoclimatology, the “faint young Sun problem. ” For the early Earth, models of stellar evolution predict a solar energy input to the climate system that is about 25% lower than today. This would result in a completely frozen world over the first 2 billion years in the history of our planet if all other parameters controlling Earth's climate had been the same. Yet there is ample evidence for the presence of liquid surface water and even life in the Archean (3.8 to 2.5 billion years before present), so some effect (or effects) must have been compensating for the faint young Sun. A wide range of possible solutions have been suggested and explored during the last four decades, with most studies focusing on higher concentrations of atmospheric greenhouse gases like carbon dioxide, methane, or ammonia. All of these solutions present considerable difficulties, however, so the faint young Sun problem cannot be regarded as solved. Here I review research on the subject, including the latest suggestions for solutions of the faint young Sun problem and recent geochemical constraints on the composition of Earth's early atmosphere. Furthermore, I will outline the most promising directions for future research. In particular I would argue that both improved geochemical constraints on the state of the Archean climate system and numerical experiments with state‐of‐the‐art climate models are required to finally assess what kept the oceans on the Archean Earth from freezing over completely.
H ii REGION VARIABILITY AND PRE-MAIN-SEQUENCE EVOLUTION

Recent observations and simulations have suggested that H ii regions around massive stars may vary in their size and emitted flux on timescales short enough to be observed. This variability can have a number of causes, ranging from environmental causes to variability of the ionizing source itself. We explore the latter possibility by considering the pre-main-sequence evolution of massive protostars and conducting numerical simulations with ionizing radiation feedback using the flash AMR hydrodynamics code. We investigate three different models: a simple zero-age main-sequence model, a self-consistent one-zone model by Offner et al., and a model fit to the tracks computed by Hosokawa & Omukai. The protostellar models show that hypercompact H ii regions around massive, isolated protostars collapse or shrink from diameters of 80 or 300 AU, depending on the model choice, down to near absence during the swelling of stellar radius that accompanies the protostar's transition from a convective to a radiative internal structure. This occurs on timescales as short as ∼3000 years.
The x-/gamma-ray camera ECLAIRs for the gamma-ray burst mission SVOM

We present ECLAIRs, the Gamma-ray burst (GRB) trigger camera to fly on-board the Chinese-French mission SVOM. ECLAIRs is a wide-field (~ 2 sr) coded mask camera with a mask transparency of 40% and a 1024 cm2 detection plane coupled to a data processing unit, so-called UGTS, which is in charge of locating GRBs in near real time thanks to image and rate triggers. We present the instrument science requirements and how the design of ECLAIRs has been optimized to increase its sensitivity to high-redshift GRBs and low-luminosity GRBs in the local Universe, by having a low-energy threshold of 4 keV. The total spectral coverage ranges from 4 to 150 keV. ECLAIRs is expected to detect ~ 200 GRBs of all types during the nominal 3 year mission lifetime. To reach a 4 keV low-energy threshold, the ECLAIRs detection plane is paved with 6400 4 × 4 mm2 and 1 mm-thick Schottky CdTe detectors. The detectors are grouped by 32, in 8×4 matrices read by a low-noise ASIC, forming elementary modules called XRDPIX. In this paper, we also present our current efforts to investigate the performance of these modules with their front-end electronics when illuminated by charged particles and/or photons using radioactive sources. All measurements are made in different instrument configurations in vacuum and with a nominal in-flight detector temperature of −20°C. This work will enable us to choose the in-flight configuration that will make the best compromise between the science performance and the in-flight operability of ECLAIRs. We will show some highlights of this work.
Comment on "Problems with Mannheim's conformal gravity program"

Recently in Phys. Rev. D 88, 027504 (2013) Yoon has suggested that there may be problems for the non-relativistic limit of the conformal gravity theory. Here we show that Yoon's results only hold because of the assumption that gravitational sources can be treated the same way that they are treated in standard Newton-Einstein gravity. Since such an assumption violates the theory's underlying conformal invariance,Yoon's conclusions are invalidated.
The effects of assembly bias on cosmological inference from galaxy-galaxy lensing and galaxy clusters

The combination of galaxy-galaxy lensing (GGL) and galaxy clustering is a promising route to measuring the amplitude of matter clustering and testing modified gravity theories of cosmic acceleration. Halo occupation distribution (HOD) modeling can extend the approach down to nonlinear scales, but galaxy assembly bias could introduce systematic errors by causing the HOD to vary with large scale environment at fixed halo mass. We investigate this problem using the mock galaxy catalogs created by Hearin & Watson (2013, HW13), which exhibit significant assembly bias because galaxy luminosity is tied to halo peak circular velocity and galaxy colour is tied to halo formation time. The preferential placement of galaxies (especially red galaxies) in older halos affects the cutoff of the mean occupation function $\langle N_\text{cen}(M_\text{min}) \rangle$ for central galaxies, with halos in overdense regions more likely to host galaxies. The effect of assembly bias on the satellite galaxy HOD is minimal. We introduce an extended, environment dependent HOD (EDHOD) prescription to describe these results and fit galaxy correlation measurements. Crucially, we find that the galaxy-matter cross-correlation coefficient, $r_{gm} \equiv \xi_{gm} \cdot [ \xi_{mm} \xi_{gg} ]^{-1/2}$, is insensitive to assembly bias on scales $r \gtrsim 1 \; h^{-1}\text{Mpc}$, even though $\xi_{gm} $ and $\xi_{gg} $ are both affected individually. We can therefore recover the correct $\xi_{mm} $ from the HW13 galaxy-galaxy and galaxy-matter correlations using either a standard HOD or EDHOD fitting method. For $M_r \leq -19$ or $M_r \leq -20$ samples the recovery of $\xi_{mm}$ is accurate to 2% or better. For a sample of red $M_r \leq -20$ galaxies we achieve 2% recovery at $r \gtrsim 2\;h^{-1}\text{Mpc}$ with EDHOD modeling but lower accuracy at smaller scales or with a standard HOD fit.
Multilevel Progressive Network With Nonlocal Channel Attention for Hyperspectral Image Super-Resolution

Deep convolutional neural networks (CNNs) have made great progress in the super-resolution (SR) of hyperspectral images (HSIs). However, most methods utilize convolution to explore local features, and global features are ignored. It is expected that combining nonlocal mechanism with CNN will improve the performance of HSI SR. This article presents a multilevel progressive HSI SR network. The dense nonlocal and local block (DNLB) is constructed to combine local and global features, which are used to reconstruct SR images at each level. Due to the high dimension of HSI, original nonlocal methods produce memory-expensive attention maps. We develop a nonlocal channel attention block to extract the global features of HSIs efficiently. Spatial-spectral gradient is injected in the nonlocal attention block to obtain better details. Furthermore, the progressive learning mode-based multilevel network is proposed to reconstruct HSI with fine details. A number of experiments demonstrate that our method can reconstruct HSIs more accurately than existing methods.
Interface-Enhanced Spin-Orbit Torques and Current-Induced Magnetization Switching of Pd /Co /AlO x Layers

Magnetic heterostructures that combine large spin-orbit torque efficiency, perpendicular magnetic anisotropy, and low resistivity are key to develop electrically-controlled memory and logic devices. Here we report on vector measurements of the current-induced spin orbit torques and magnetization switching in perpendicularly magnetized Pd/Co/AlO$_x$ layers as a function of Pd thickness. We find sizeable damping-like (DL) and field-like (FL) torques, of the order of 1~mT per $10^7$~A/cm$^2$, which have different thickness and magnetization angle dependence. The analysis of the DL torque efficiency per unit current density and electric field using drift-diffusion theory leads to an effective spin Hall angle and spin diffusion length of Pd larger than 0.03 and 7~nm, respectively. The FL SOT includes a significant interface contribution, is larger than estimated using drift-diffusion parameters, and is further strongly enhanced upon rotation of the magnetization from the out-of-plane to the in-plane direction. Finally, taking advantage of the large spin-orbit torques in this system, we demonstrate bipolar magnetization switching of Pd/Co/AlO$_x$ layers with similar current density as used for Pt/Co layers with comparable perpendicular magnetic anisotropy.
Diffuse Neutrino Intensity from the Inner Jets of Active Galactic Nuclei: Impacts of External Photon Fields and the Blazar Sequence

We study high-energy neutrino production in inner jets of radio-loud active galactic nuclei (AGN), taking into account effects of external photon fields and the blazar sequence. We show that the resulting diffuse neutrino intensity is dominated by quasar-hosted blazars, in particular, flat spectrum radio quasars, and that PeV-EeV neutrino production due to photohadronic interactions with broadline and dust radiation is unavoidable if the AGN inner jets are ultrahigh-energy cosmic-ray (UHECR) sources. Their neutrino spectrum has a cutoff feature around PeV energies since target photons are due to Ly$\alpha$ emission. Because of infrared photons provided by the dust torus, neutrino spectra above PeV energies are too hard to be consistent with the IceCube data unless the proton spectral index is steeper than 2.5, or the maximum proton energy is $\lesssim100$ PeV. Thus, the simple model has difficulty in explaining the IceCube data. For the cumulative neutrino intensity from blazars to exceed $\sim{10}^{-8}~{\rm GeV}~{\rm cm}^{-2}~{\rm s}^{-1}~{\rm sr}^{-1}$, their local cosmic-ray energy generation rate would be $\sim10-100$ times larger than the local UHECR emissivity, but is comparable to the averaged gamma-ray blazar emissivity. Interestingly, future detectors such as the Askaryan Radio Array can detect $\sim0.1-1$ EeV neutrinos even in more conservative cases, allowing us to indirectly test the hypothesis that UHECRs are produced in the inner jets. We find that the diffuse neutrino intensity from radio-loud AGN is dominated by blazars with gamma-ray luminosity of $\gtrsim10^{48}~{\rm erg}~{\rm s}^{-1}$, and the arrival directions of their $\sim1-100$ PeV neutrinos correlate with the luminous blazars detected by Fermi.
DIRECT DIAGNOSTICS OF FORMING MASSIVE STARS: STELLAR PULSATION AND PERIODIC VARIABILITY OF MASER SOURCES

The 6.7 GHz methanol maser emission, a tracer of forming massive stars, sometimes shows enigmatic periodic flux variations over several 10–100 days. In this Letter, we propose that these periodic variations could be explained by the pulsation of massive protostars growing under rapid mass accretion with rates of . Our stellar evolution calculations predict that the massive protostars have very large radii exceeding 100 R☉ at maximum, and here we study the pulsational stability of such bloated protostars by way of the linear stability analysis. We show that the protostar becomes pulsationally unstable with various periods of several 10–100 days depending on different accretion rates. With the fact that the stellar luminosity when the star is pulsationally unstable also depends on the accretion rate, we derive the period–luminosity relation log (L/ L☉) = 4.62 + 0.98log (P/100 days), which is testable with future observations. Our models further show that the radius and mass of the pulsating massive protostar should also depend on the period. It would be possible to infer such protostellar properties and the accretion rate with the observed period. Measuring the maser periods enables a direct diagnosis of the structure of accreting massive protostars, which are deeply embedded in dense gas and are inaccessible with other observations.
X-RAY-SELECTED GALAXY GROUPS IN BOÖTES

We present the X-ray and optical properties of the galaxy groups selected in the Chandra X-Boötes survey. We used follow-up Chandra observations to better define the group sample and their X-ray properties. Group redshifts were measured from the AGN and Galaxy Evolution Survey spectroscopic data. We used photometric data from the NOAO Deep Wide Field Survey to estimate the group richness (Ngals) and the optical luminosity (Lopt). Our final sample comprises 32 systems at z < 1.75 with 14 below z = 0.35. For these 14 systems, we estimate velocity dispersions (σgr) and perform a virial analysis to obtain the radii (R200 and R500) and total masses (M200 and M500) for groups with at least 5 galaxy members. We use the Chandra X-ray observations to derive the X-ray luminosity (LX). We examine the performance of the group properties σgr, Lopt, and LX, as proxies for the group mass. Understanding how well these observables measure the total mass is important to estimate how precisely the cluster/group mass function is determined. Exploring the scaling relations built with the X-Boötes sample and comparing these with samples from the literature, we find a break in the LX–M500 relation at approximately M500 = 5 × 1013 M☉ (for M500 > 5 × 1013 M☉, , while for M500 ⩽ 5 × 1013 M☉, ). Thus, the mass–luminosity relation for galaxy groups cannot be described by the same power law as galaxy clusters. A possible explanation for this break is the dynamical friction, tidal interactions, and projection effects that reduce the velocity dispersion values of the galaxy groups. By extending the cluster luminosity function to the group regime, we predict the number of groups that new X-ray surveys, particularly eROSITA, will detect. Based on our cluster/group luminosity function estimates, eROSITA will identify ∼1800 groups (LX = 1041–1043 erg s−1) within a distance of 200 Mpc. Since groups lie in large-scale filaments, this group sample will map the large-scale structure of the local universe.