Miracle-dz/UniFAR-FTUs huggingface dataset:
Lyman alpha emission from the first galaxies: Implications of UV backgrounds and the formation of molecules

The Lyman alpha line is a robust tracer of high redshift galaxies. We present estimates of Lyman alpha emission from a protogalactic halo illuminated by UV background radiation fields with various intensities. For this purpose, we performed cosmological hydrodynamics simulations with the adaptive mesh refinement code FLASH, including a detailed network for primordial chemistry, comprising the formation of primordial molecules, a multi-level model for the hydrogen atom as well as the photo-ionization and photo-dissociation processes in a UV background. We find that the presence of a background radiation field J21 excites the emission of Lyman alpha photons, increasing the Lyman α luminosity up to two orders of magnitude. For a halo of ~ 1010 M⊙, we find that a maximum flux of 5 × 10-15 erg cm-2 s-1 is obtained for J21 × fesc = 0.1, where fesc is the escape fraction of the ionizing radiation. Depending on the environmental conditions, the flux may vary by three orders of magnitude. For J21 × fesc > 0.1 the Lyman alpha luminosity decreases as the atomic hydrogen abundance becomes rather small. The fluxes derived here can be probed using Subaru and the upcoming James Webb Space Telescope. The emission of Lyman alpha photons is extended and comes from the envelope of the halo rather than its core. In the center of the halo, line trapping becomes effective above columns of 1022 cm-2 and suppresses the emission of Lyman alpha. In addition, cooling by primordial molecules may decrease the gas temperature in the central region, which further reduces Lyman α emission. In the central core, H2 is photo-dissociated for a background flux of J21 ≥ 1000. For weaker radiation fields, i.e. J21 <0.1, H2 and HD cooling are particularly strong in the center of the halo, leading to gas temperatures as low as ~100 K. We also performed a parameter study with different escape fractions of ionizing photons and explored the relative role of ionizing and dissociating radiation. We find that Lyman alpha emission depends more on the strength of the ionizing background. For a constant ionizing background, the Lyman α flux increases at least by an order of magnitude for stronger photodissociation.
Scattering of gravity waves in subcritical flows over an obstacle

We numerically study the scattering coefficients of linear water waves on stationary flows above a localized obstacle. We compare the scattering on trans- and subcritical flows, and then focus on the latter which have been used in recent analog gravity experiments. The main difference concerns the magnitude of the mode amplification: whereas transcritical flows display a large amplification (which is generally in good agreement with the Hawking prediction), this effect is heavily suppressed in subcritical flows. This is due to the transmission across the obstacle for frequencies less than some critical value. As a result, subcritical flows display high- and low-frequency behaviors separated by a narrow band around the critical frequency. In the low-frequency regime, transmission of long wavelengths is accompanied by non-adiabatic scattering into short wavelengths, whose spectrum is approximately linear in frequency. By contrast, in the high-frequency regime, no simple description seems to exist. In particular, for obstacles similar to those recently used, we observe that the upstream slope still affects the scattering on the downstream side because of some residual transmission.
A NEW METHOD TO ESTIMATE LOCAL PITCH ANGLES IN SPIRAL GALAXIES: APPLICATION TO SPIRAL ARMS AND FEATHERS IN M81 AND M51

We examine 8 &mgr; m ? > IRAC images of the grand design two-arm spiral galaxies M81 and M51 using a new method whereby pitch angles are locally determined as a function of scale and position, in contrast to traditional Fourier transform spectral analyses which fit to average pitch angles for whole galaxies. The new analysis is based on a correlation between pieces of a galaxy in circular windows of ( ln R , θ ) ? > space and logarithmic spirals with various pitch angles. The diameter of the windows is varied to study different scales. The result is a best-fit pitch angle to the spiral structure as a function of position and scale, or a distribution function of pitch angles as a function of scale for a given galactic region or area. We apply the method to determine the distribution of pitch angles in the arm and interarm regions of these two galaxies. In the arms, the method reproduces the known pitch angles for the main spirals on a large scale, but also shows higher pitch angles on smaller scales resulting from dust feathers. For the interarms, there is a broad distribution of pitch angles representing the continuation and evolution of the spiral arm feathers as the flow moves into the interarm regions. Our method shows a multiplicity of spiral structures on different scales, as expected from gas flow processes in a gravitating, turbulent and shearing interstellar medium. We also present results for M81 using classical 1D and 2D Fourier transforms, together with a new correlation method, which shows good agreement with conventional 2D Fourier transforms.
Inclusive and exclusive diffractive production of dilepton pairs in proton-proton collisions at high energies

We calculate for the first time cross sections for single and central diffractive as well as exclusive diffractive production of dilepton pairs in proton-proton collisions. Several differential distributions are shown. The inclusive diffractive processes are calculated using diffractive parton distributions extracted from the analysis of diffractive structure function and dijet production at HERA. We find that the inclusive single-diffractive Drell-Yan process is by about 2 orders of magnitude smaller than ordinary Drell-Yan process. The central-diffractive processes are smaller by one order of magnitude compared to single-diffractive ones. We consider also exclusive production of dilepton pairs. The exclusive photon-pomeron (pomeron-photon) process constitutes a background to the QED photon-photon process proposed to be used for controlling luminosity at LHC. Both processes are compared then in several differential distributions. We find a region of the phase space where the photon-pomeron or pomeron-photon contributions can be larger than the photon-photon one.
The Impact of Migration on The Assimilation of The Customs and Traditions of The Bugis Community in The Fisheries Activity

Migration has affected the customs and culture of the Bugis people. As immigrants, their local beliefs, customs and culture have been assimilated into their daily activities. Thus, this study was conducted to examine the knowledge of the customs and culture practised in fishing activities among the Bugis people by comparing the past with the present. A series of qualitative in-depth interviews were carried out to 10 informants in five areas in the Pontian district, Johor. This study found that a number of systems, culture and principles such as pemmali , penggaderreng and ade’ are still practised in their fishing activities, though there are some assimilation of local religion and culture occurred. Many of the Bugis traditions and culture that contradict Islamic beliefs have been left out by the Bugis people who have converted Muslim. Reciting Quran and salawat have now been practising in the beliefs. These practises are due to the influences of Islamic traditions and culture in the Bugis fisheries activity, as well as local people and the current technology changes. In order to sustain the original customs and culture of Bugis, the involvement of young generation and increasing cultural activities should be emphasized so that the Bugis heritage is not forgotten. The original customs and culture however, must not contradict Islamic beliefs.
Structure of Abell 1995 from optical and X-ray data: a galaxy cluster with an elongated radio halo

Context. Abell 1995 is a puzzling galaxy cluster hosting a powerful radio halo, but it has not yet been recognized as a obvious cluster merger, as usually expected for clusters with diffuse radio emission. Aims. We aim at an exhaustive analysis of the internal structure of Abell 1995 to verify if this cluster is really dynamically re laxed, as reported in previous studies. Methods. We base our analysis on new and archival spectroscopic and photometric data for 126 galaxies in the field of Abell 1995. The study of the hot intracluster medium was performed on X-ray archival data. Results. Based on 87 fiducial cluster members, we have computed the ave rage cluster redshift h zi= 0.322 and the global radial velocity dispersion σV ∼ 1300 km s −1 . We detect two main optical subclusters separated by 1.5 ′ that cause the known NE-SW elongation of the galaxy distribution and a significant velo city gradient in the same direction. As for the X-ray analysis, we confirm that the intracluster medium is mildly elongated, but we also detect three X-ray peaks. Two X-ray peaks are offset with respect to the two galaxy peaks and lie between them, thus suggesting a bimodal merger caught in a phase of post core-core passage. The third X-ray peak lies between the NE galaxy peak and a third, minor galaxy peak suggesting a more complex merger. The diffi culty of separating the two main systems leads to a large uncertainty on the line‐of-sight (LOS) velocity separation and the system mass: �Vrf,LOS = 600‐2000 km s −1 and Msys = 2‐5×10 15 h −1 70 M⊙, respectively. Simple analytical arguments suggest a merging scenario for Abell 1995, where two main subsystems are seen just after the collision with an intermediate projection angle. Conclusions. The high mass of Abell 1995 and the evidence of merging suggest it is not atypical among clusters with known radio halos. Interestingly, our findings reinforce the previous e vidence for the peculiar dichotomy between the dark matter and galaxy distributions observed in this cluster.
The Semigroup Generated by the Similarity Class of a Singular Matrix

Let A be a singular matrix of M n (𝕂), where 𝕂 is an arbitrary field. Using canonical forms, we give a new proof that the sub-semigroup of ( n (𝕂), ×) generated by the similarity class of A is the set of matrices of M n (𝕂) with a rank lesser than or equal to that of A.
The contribution of AGN to the sub-mm population

We find that X-ray sources in the Extended Chandra Deep Field South are strongly spatially correlated with LABOCA 870 micron sources. We investigate the dependence of this correlation on X-ray flux, hardness ratio and column density, finding that specifically faint and absorbed X-ray sources are significant sub-mm emitters. In the X-ray source redshift subsample we confirm the previous result that higher luminosity sources (L_X>10^44 ergs/s) have greater 870um fluxes but we also find that this subsample selects against absorbed sources, faint in X-ray flux. Overall, we find that X-ray sources contribute 1.5 \pm 0.1 Jy/deg^2 to the sub-mm background, ~3% of the total, in agreement with the prediction of an obscured AGN model which also gives a reasonable fit to the bright sub-mm source counts. This non-unified model also suggests that when Compton-thick, X-ray-undetected sources are included, then the fractional AGN contribution to the sub-mm background would rise from ~3% to a total of 25-40%, although in a unified model the AGN contribution would only reach ~13%, because the sub-mm flux of the X-ray sources is then more representative of the whole AGN population. Measurements of the dependence of sub-mm flux on X-ray flux, luminosity and column density all agree well with the predictions of the non-unified AGN model. Heavily absorbed, X-ray-undetected AGN could explain the further cross-correlation we find between sub-mm sources and z > 0.5 red galaxies. We conclude that sub-mm galaxies may contain the long-sought absorbed AGN population needed to explain the X-ray background.
Maximized exoEarth candidate yields for starshades

Abstract. The design and scale of a future mission to directly image and characterize potentially Earth-like planets will be impacted, to some degree, by the expected yield of such planets. Recent efforts to increase the estimated yields, by creating observation plans optimized for the detection and characterization of Earth-twins, have focused solely on coronagraphic instruments; starshade-based missions could benefit from a similar analysis. Here we explore how to prioritize observations for a starshade given the limiting resources of both fuel and time, present analytic expressions to estimate fuel use, and provide efficient numerical techniques for maximizing the yield of starshades. We implemented these techniques to create an approximate design reference mission code for starshades and used this code to investigate how exoEarth candidate yield responds to changes in mission, instrument, and astrophysical parameters for missions with a single starshade. We find that a starshade mission operates most efficiently somewhere between the fuel- and exposuretime-limited regimes and, as a result, is less sensitive to photometric noise sources as well as parameters controlling the photon collection rate in comparison to a coronagraph. We produced optimistic yield curves for starshades, assuming our optimized observation plans are schedulable and future starshades are not thrust-limited. Given these yield curves, detecting and characterizing several dozen exoEarth candidates requires either multiple starshades or an ηEarth≳0.3.
Structural and electronic transformation in low-angle twisted bilayer graphene

Experiments on bilayer graphene unveiled a fascinating realization of stacking disorder where triangular domains with well-defined Bernal stacking are delimited by a hexagonal network of strain solitons. Here we show by means of numerical simulations that this is a consequence of a structural transformation of the moiré pattern inherent to twisted bilayer graphene taking place at twist angles θ below a crossover angle θ⋆=1.2∘. The transformation is governed by the interplay between the interlayer van der Waals interaction and the in-plane strain field, and is revealed by a change in the functional form of the twist energy density. This transformation unveils an electronic regime characteristic of vanishing twist angles in which the charge density converges, though not uniformly, to that of ideal bilayer graphene with Bernal stacking. On the other hand, the stacking domain boundaries form a distinct charge density pattern that provides the STM signature of the hexagonal solitonic network.
A Letter of Intent to Install a milli-charged Particle Detector at LHC P5

In this LOI we propose a dedicated experiment that would detect "milli-charged" particles produced by pp collisions at LHC Point 5. The experiment would be installed during LS2 in the vestigial drainage gallery above UXC and would not interfere with CMS operations. With 300 fb$^{-1}$ of integrated luminosity, sensitivity to a particle with charge $\mathcal{O}(10^{-3})~e$ can be achieved for masses of $\mathcal{O}(1)$ GeV, and charge $\mathcal{O}(10^{-2})~e$ for masses of $\mathcal{O}(10)$ GeV, greatly extending the parameter space explored for particles with small charge and masses above 100 MeV.
OBSERVATIONAL EVIDENCE FOR ACTIVE GALACTIC NUCLEI FEEDBACK AT THE PARSEC SCALE

In a hot accretion flow, the radiation from the innermost region of the flow propagates outward and heats the electrons at large radii via Compton scattering. It has been shown in previous works that if the radiation is strong enough, L ≳ 2%LEdd, the electrons at the Bondi radius (rB ∼ 105rs) will be heated to above the virial temperature; thus, the accretion will be stopped. The accretion will recover after the gas cools down. This results in the oscillation of the black hole activity. In this paper, we show that this mechanism is the origin of the intermittent activity of some compact young radio sources. Such intermittency is required to explain the population of these sources. We calculate the timescales of the black hole oscillation and find that the durations of active and inactive phases are 3 × 104(0.1/α)(M/108 M☉)(L/2%LEdd)−1/2 yr and 105(α/0.1)(M/108 M☉) yr, respectively, consistent with those required to explain observations. Such feedback occurring at the parsec scale should be common in low-luminosity active galactic nuclei and should be considered when we consider their matter and energy output.
Oxygen abundance distributions in six late-type galaxies based on SALT spectra of H II regions

Spectra of 34 H ii regions in the late-type galaxies NGC 1087, NGC 2967, NGC 3023, NGC 4030, NGC 4123, and NGC 4517A were observed with the South African Large Telescope (SALT). In all 34 H ii regions, oxygen abundances were determined through the “counterpart” method (C method). Additionally, in two H ii regions in which we detected auroral lines, we measured oxygen abundances with the classic Te method. We also estimated the abundances in our H ii regions using the O3N2 and N2 calibrations and compared those with the C-based abundances. With these data, we examined the radial abundance distributions in the disks of our target galaxies. We derived surface-brightness profiles and other characteristics of the disks (the surface brightness at the disk center and the disk scale length) in three photometric bands for each galaxy using publicly available photometric imaging data. The radial distributions of the oxygen abundances predicted by the relation between abundance and disk surface brightness in the W 1b and obtained for spiral galaxies in our previous study are close to the radial distributions of the oxygen abundances determined from the analysis of the emission line spectra for four galaxies where this relation is applicable. Hence, when the surface-brightness profile of a late-type galaxy is known, this parametric relation can be used to estimate the likely present-day oxygen abundance in the disk of the galaxy.
The Co-creation Paradox: Small Towns and the Promise and Limits of Collaborative Governance for Low-Carbon, Sustainable Futures

Co-creation is considered a ‘near perfect strategy’ for resolving complex and unruly public problems, such as climate change. Based on data collected among small Scandinavian towns, this article investigates the role of co-creation in the urban governance of climate- and sustainability responses by looking at their vertical and horizontal integration in the wider polycentric governance framework. The article has a two-fold aim. First, it develops an analytical framework for investigating how small towns and municipalities navigate in a range of governance contexts based on two strains of theories on collaborative governance and urban climate governance. Second, it applies this framework to a comparative study of small towns to analyse how co-creation plays a strategic role across types and scales of governance in relation to an evolving climate agenda. The article finds that new forms of public leadership in each of the three municipalities and towns is a main factor in the ‘remaking’ of collaborative planning arenas, triple helix partnerships, business alliances, city networks and collaborative pilot projects, much in a similar manner as observed in global cities. Co-creation is extensively employed as a proactive policy- and leadership instrument. However, the nature of response is uneven across the cases compared. A co-creation paradox is suggested: limited municipal politico-administrative leadership and capacity correspond to a low level of ability to engage in co-creation of solutions. This implies that those organisations with the most need for co-creation may have the least capacity to do so.
Third post-Newtonian gravitational waveforms for compact binary systems in general orbits: Instantaneous terms

We compute the instantaneous contributions to the spherical harmonic modes of gravitational waveforms from compact binary systems in general orbits up to the third post-Newtonian (PN) order. We further extend these results for compact binaries in quasielliptical orbits using the 3PN quasi-Keplerian representation of the conserved dynamics of compact binaries in eccentric orbits. Using the multipolar post-Minkowskian formalism, starting from the different mass and current-type multipole moments, we compute the spin-weighted spherical harmonic decomposition of the instantaneous part of the gravitational waveform. These are terms which are functions of the retarded time and do not depend on the history of the binary evolution. Together with the hereditary part, which depends on the binary's dynamical history, these waveforms form the basis for construction of accurate templates for the detection of gravitational wave signals from binaries moving in quasielliptical orbits.
Dynamical evolution of massive black holes in galactic-scale N-body simulations – introducing the regularized tree code ‘rvine’

We present a hybrid code combining the OpenMP-parallel tree code VINE with an algorithmic chain regularization scheme. The new code, called "rVINE", aims to significantly improve the accuracy of close encounters of massive bodies with supermassive black holes in galaxy-scale numerical simulations. We demonstrate the capabilities of the code by studying two test problems, the sinking of a single massive black hole to the centre of a gas-free galaxy due to dynamical friction and the hardening of a supermassive black hole binary due to close stellar encounters. We show that results obtained with rVINE compare well with NBODY7 for problems with particle numbers that can be simulated with NBODY7. In particular, in both NBODY7 and rVINE we find a clear N-dependence of the binary hardening rate, a low binary eccentricity and moderate eccentricity evolution, as well as the conversion of the galaxy's inner density profile from a cusp to a a core via the ejection of stars at high velocity. The much larger number of particles that can be handled by rVINE will open up exciting opportunities to model stellar dynamics close to SMBHs much more accurately in a realistic galactic context. This will help to remedy the inherent limitations of commonly used tree solvers to follow the correct dynamical evolution of black holes in galaxy scale simulations.
Lower Limits on the Nucleosynthesis of 44Ti and 60Fe in the Dynamic Spiral-arm Cosmic-Ray Propagation Model

We have previously focused on studying the electron-capture isotopes within the dynamic spiral-arms cosmic-rays propagation model and empirically derived the energy dependence of the electron attachment rate using the observation of 49Ti/49V and 51V/51Cr ratios in cosmic rays. We have also shown how this relation recovers the energy dependence seen in the lab measurements. In this work, we use this relation to construct the 44Ti/44Ca ratio and place a lower limit on the amount of 44Ti that is required for it to be nucleosynthesized at the source. The results also imply that the acceleration process of the radioisotopes cannot be much longer than a century timescale (or else the required nucleosynthesized amount has to be correspondingly larger). We also provide a similar lower limit on the source 60Fe by comparing to the recently observed 60Fe/56Fe.