Miracle-dz/UniFAR-FTUs huggingface dataset:
Was the "naked burst" GRB 050421 really naked ?

A few long gamma-ray bursts such as GRB 050421 show no afterglow emission beyond the usual initial steep decay phase. It has been suggested that these events correspond to "naked" bursts that occur in a very low density environment. We reconsider this possibility in the context of various scenarios for the origin of the afterglow. In the standard model where the afterglow results from the forward shock as well as in the alternative model where the afterglow comes from the reverse shock, we aim to obtain constraints on the density of the environment, the microphysics parameters, or the Lorentz factor of the ejecta, which are imposed by the absence of a detected afterglow. For the two models we compute the afterglow evolution for different values of the external density (uniform or wind medium) and various burst parameters. We then compare our results to the Swift data of GRB 050421, which is the best example of a long burst without afterglow. In the standard model we show that consistency with the data imposes that the external density does not exceed 1E-5 cm-3 or that the microphysics parameters are very small with epsilon_e <~ 1E-2 and epsilon_B <~ 1E-4. If the afterglow is caused by the reverse shock, we find that its contribution can be strongly reduced if the central source has mainly emitted fast-moving material (with less than 10 - 30 % of the kinetic energy at Gamma<100 and was located in a dense environment. The two considered scenarios therefore lead to opposite constraints on the circumburst medium. The high-density environment, favored by the reverse shock model, better corresponds to what is expected if the burst progenitor was a massive star.
Morphology and structure of BzK-selected galaxies at z ∼ 2 in the CANDELS-COSMOS field

Utilizing a BzK-selection technique, we obtain 14550 star-forming galaxies (sBzKs) and 1763 passive galaxies (pBzKs) at z ∼ 2 from the K-selected (KAB < 22.5) catalog in the COSMOS/UltraVISTA field. The differential number counts of sBzKs and pBzKs are consistent with the results from the literature. Compared to the observed results, semi-analytic models of galaxy formation and evolution provide too few (many) galaxies at the high (low) mass end. Moreover, we find that the star formation rate and stellar mass of sBzKs follow the relation of the main sequence. Based on HST/Wide Field Camera 3 F160W imaging, we find a wide range of morphological diversities for sBzKs, from diffuse to early-type spiral structures, with relatively high M20, large size and low G, while pBzKs have elliptical-like compact morphologies with lower M20, smaller size and higher G, indicating a more concentrated and symmetric spatial extent of stellar population distribution in pBzKs than sBzKs. Furthermore, the sizes of pBzKs (sBzKs) at z ∼ 2 are on average two to three (one to two) times smaller than those of local early-type (late-type) galaxies with similar stellar mass. Our findings imply that the two classes have different evolution models and mass assembly histories.
Convective line shifts for the Gaia RVS from the CIFIST 3D model atmosphere grid

Context. To derive space velocities of stars along the line of sight from wavelength shifts in stellar spectra requires accounting for a number of second-order effects. For most stars, gravitational redshifts, convective blueshifts, and transverse stellar motion are the dominant contributors. Aims. We provide theoretical corrections for the net velocity shifts due to convection expected for the measurements from the Gaia Radial Velocity Spectrometer (RVS). Methods. We used a set of three-dimensional time-dependent simulations of stellar surface convection computed with CO5BOLD to calculate spectra of late-type stars in the Gaia RVS range and to infer the net velocity offset that convective motions will induce in radial velocities derived by cross-correlation. Results. The net velocity shifts derived by cross-correlation depend both on the wavelength range and spectral resolution of the observations. Convective shifts for Gaia RVS observations are less than 0.1 km s −1 for late-K-type stars, and they increase with stellar mass, reaching about 0.3 km s −1 or more for early F-type dwarfs. This tendency is the result of an increase with effective temperature in both temperature and velocity fluctuations in the line-forming region. Our simulations also indicate that the net RVS convective shifts can be positive (i.e. redshifts) in some cases. Overall, the blueshifts weaken slightly with increasing surface gravity, and are enhanced at low metallicity. Gravitational redshifts amount to 0.7 km s −1 and dominate convective blueshifts for dwarfs, but become
Electroluminescence from Strained Ge membranes and Implications for an Efficient Si-Compatible Laser

We demonstrate room-temperature electroluminescence (EL) from light-emitting diodes (LED) on highly strained germanium (Ge) membranes. An external stressor technique was employed to introduce a 0.76% bi-axial tensile strain in the active region of a vertical PN junction. Electrical measurements show an on-off ratio increase of one order of magnitude in membrane LEDs compared to bulk. The EL spectrum from the 0.76% strained Ge LED shows a 100nm redshift of the center wavelength because of the strain-induced direct band gap reduction. Finally, using tight-binding and FDTD simulations, we discuss the implications for highly efficient Ge lasers.
Many-body localization edge in the random-field Heisenberg chain

The authors study the phenomena of many-body localization in a random field Heisenberg chain. In this paper the authors use a shift-inverse exact diagonalization approach that allows them to study the mid-spectrum spectral properties of the model for system sizes of up to N=22. This has allow the authors to identify the many-body localization edge.
The Galactic Centre - a laboratory for starburst galaxies (?)

Abstract The Galactic centre – as the closest galactic nucleus – holds both intrinsic interest and possibly represents a useful analogue to starburst nuclei which we can observe with orders of magnitude finer detail than these external systems. The environmental conditions in the GC – here taken to mean the inner 200 pc in diameter of the Milky Way – are extreme with respect to those typically encountered in the Galactic disk. The energy densities of the various GC ISM components are typically ~two orders of magnitude larger than those found locally and the star-formation rate density ~three orders of magnitude larger. Unusually within the Galaxy, the Galactic centre exhibits hard-spectrum, diffuse TeV (=1012 eV) gamma-ray emission spatially coincident with the region's molecular gas. Recently the nuclei of local starburst galaxies NGC 253 and M82 have also been detected in gamma-rays of such energies. We have embarked on an extended campaign of modelling the broadband (radio continuum to TeV gamma-ray), non- thermal signals received from the inner 200 pc of the Galaxy. On the basis of this modelling we find that star-formation and associated supernova activity is the ultimate driver of the region's non-thermal activity. This activity drives a large-scale wind of hot plasma and cosmic rays out of the GC. The wind advects the locally-accelerated cosmic rays quickly, before they can lose much energy in situ or penetrate into the densest molecular gas cores where star-formation occurs. The cosmic rays can, however, heat/ionize the lower density/warm H2 phase enveloping the cores. On very large scales (~10 kpc) the non-thermal signature of the escaping GC cosmic rays has probably been detected recently as the spectacular ‘Fermi bubbles’ and corresponding ‘YWMAP haze’.
Towards a unified model of stellar rotation

The effects of rapid rotation on stellar evolution can be profound. We are now beginning to gather enough data to allow a realistic comparison between different physical models. Two key tests for any theory of stellar rotation are first whether it can match observations of the enrichment of nitrogen, and potentially other elements, in clusters containing rapid rotators and secondly whether it can reproduce the observed broadening of the main sequence in the Hertzsprung-Russel diagram. Models of stellar rotation have been steadily increasing in number and complexity over the past two decades but the lack of data makes it difficult to determine whether such additions actually give a closer reflection of reality. One of the most poorly explored features of stellar rotation models is the treatment of angular momentum transport within convective zones. If we treat the core as having uniform specific angular momentum the angular momentum distribution in the star, for a given surface rotation, is dramatically different from what it is when we assume the star rotates as a solid body. The uniform specific angular momentum also generates strong shears which can drive additional transport of chemical elements close to the boundary of a convection zone. A comparison of different models and their reproduction of observable properties with otherwise identical input physics is essential to properly distinguish between them. We compare detailed grids of stellar evolution tracks of intermediate and high-mass stars produced using several models for rotation generated with our new stellar rotation code.
On the Determination of Elastic and Inelastic Nuclear Observables from Lattice QCD

One of the overarching goals of nuclear physics is to rigorously compute properties of hadronic systems directly from the fundamental theory of the strong interaction, Quantum Chromodynamics (QCD). Currently, lattice QCD (LQCD) provides the only reliable option for performing calculations of low-energy hadronic observables. LQCD calculations are necessarily performed in a finite Euclidean spacetime. As a result, it is necessary to construct formalism that maps the finite-volume observables determined via LQCD to the infinite-volume quantities of interest. This methodology is commonly referred to as the Luscher method, as it was Martin Luscher who first developed such formalism for scalar bosons with zero total momentum below inelastic thresholds. In this work, we review recent progress on the generalization of this formalism. We present a detailed derivation of the extension of Luscher's seminal work for multi-channel two-body scalar systems, two-nucleon non-relativistic systems, and three-body non-relativistic scalar systems. For all of these scenarios we allow for the total momenta of the systems of interest to be nonzero. We also present steps towards being able to study weak processes involving two-nucleon systems, in particular we show how to determine the transition amplitude for proton-proton fusion (pp->e^+ + nu_e) directly from LQCD.
Interpreting the Higgs

The LHC and Tevatron Higgs data are interpreted as constraints on an eective theory of a Higgs boson with mass mh ’ 125 GeV. We focus on the h ! , h ! ZZ ! 4l, and h! WW ! 2l2 channels at the LHC, and the b b channel at the Tevatron, which are currently the most sensitive probes of a Higgs with such a mass. Combining the available data in these channels, we derive the preferred regions of the parameter space of the eective theory. We further provide the mapping between the eective theory and the relevant Higgs event rates, facilitating future extraction of the preferred region by the ATLAS and CMS collaborations.
ON INFERRING EXTINCTION LAWS IN z ∼ 6 QUASARS AS SIGNATURES OF SUPERNOVA DUST

Unusual extinction curves of high-redshift QSOs have been taken as evidence that dust is primarily produced by supernovae at high redshift. In particular, the 3000 Å Todini–Ferrara–Maiolino kink in the extinction curve of the z = 6.20 SDSS J1048+4637 has been attributed to supernova dust. Here we discuss the challenges in inferring robust extinction curves of high-redshift QSOs and critically assess previous claims of detection of supernova dust. In particular, we address the sensitivity to the choice of intrinsic QSO spectrum, the need for a long wavelength baseline, and the drawbacks in fitting theoretical extinction curves. In a sample of 21 QSOs at z ∼ 6 we detect significant ultraviolet extinction using existing broadband optical, near-infrared, and Spitzer photometry. The median extinction curve is consistent with a Small Magellanic Cloud curve with A1450 ∼ 0.7 mag and does not exhibit any conspicuous (rest frame) 2175 Å or 3000 Å features. For two QSOs, SDSS J1044−0125 at z = 5.78 and SDSS J1030+0524 at z = 6.31, we further present X-shooter spectra covering the wavelength range 0.9–2.5 μm. The resulting non-parametric extinction curves do not exhibit the 3000 Å kink. Finally, in a re-analysis of literature spectra of SDSS J1048+4637, we do not find evidence for a conspicuous kink. We conclude that the existing evidence for a 3000 Å feature is weak and that the overall dust properties at high and low redshifts show no significant differences. This, however, does not preclude supernovae from dominating the dust budget at high redshift.
Symmetries of linearized gravity from adjoint operators

Based on operator identities and their formal adjoints, we derive two symmetry operators for the linearized Einstein operator on vacuum backgrounds of Petrov type D and in particular the Kerr spacetime. One of them is of differential order four and coincides with a result of Cohen and Kegeles. The other one is a new operator of differential order six. The corresponding operator identities are based on the Teukolsky equation and the Teukolsky-Starobinski identities, respectively. The method applies to other field equations as well, which is illustrated with the Maxwell equation. The resulting symmetry operators are connected to Hertz and Debye potentials as well as to the separability of the Teukolsky equation for both Maxwell and linearized gravity.
Evolutionary-algorithm-based analysis of gravitational microlensing light curves

A new algorithm developed to perform autonomous fitting of gravitational microlensing light curves is presented. The new algorithm is conceptually simple, versatile and robust, and parallelizes trivially; it combines features of extant evolutionary algorithms with some novel ones, and fares well on the problem of fitting binary-lens microlensing light curves, as well as on a number of other difficult optimization problems. Success rates in excess of 90 per cent are achieved when fitting synthetic though noisy binary-lens light curves, allowing no more than 20 min per fit on a desktop computer; this success rate is shown to compare very favourably with that of both a conventional (iterated simplex) algorithm, and a more state-of-the-art, artificial neural network based approach. As such, this work provides proof of concept for the use of an evolutionary algorithm as the basis for real-time, autonomous modelling of microlensing events. Further work is required to investigate how the algorithm will fare when faced with more complex and realistic microlensing modelling problems; it is, however, argued here that the use of parallel computing platforms, such as inexpensive graphics processing units, should allow fitting times to be constrained to under an hour, even when dealing with complicated microlensing models. In any event, it is hoped that this work might stimulate some interest in evolutionary algorithms, and that the algorithm described here might prove useful for solving microlensing and/or more general model-fitting problems.
The Quad as a Security Actor

When the Quad briefly emerged in 2007-8 among Australia, India, Japan, and the United States, this minilateral was referred to as the Quadrilateral Security Dialogue. Although some member states occasionally still use that term-often casually-it has been eschewed as a formal designation. Indeed, Quad members have gone out of their way to highlight a softer purpose rather than a security framing for the coalition. They have emphasized the idea of the group as a solutions provider for regional problems, including the Covid-19 crisis and climate change, while simultaneously officials have either denied or downplayed the grouping's security dimension.1 In September 2021, for instance, a senior U.S. official emphasized that the Quad "is not a regional security organization. " The official further added that "there is not a military dimension.or security dimension" to the grouping.2However, while the Quad is not a regional security organization or alliance and does not involve formal security commitments or treaty obligations, it does have security and even some military dimensions. This element may not be evident in members' public statements, but as this essay argues, it is a key component of the Quad and the cooperation between its members.The Quad's resurrection lay in the need to respond to a security challenge-a more assertive and powerful China. This was not the only driver, but without it, the Quad was neither necessary nor possible. The member states' desire to respond to this challenge by shaping a favorable balance of power and building resilience in the region has led to several lines of effort, including in the defense and security domains. Among other elements, these interactions have involved building on a relatively low base of member-state interconnection in these sectors, particularly with India. Members' engagement in these realms has been evident in three areas: (1) security consultations and activities via the Quad, (2) sub-Quad activities, involving the deepening of ties between the Quad partners bilaterally and trilaterally, and (3) supra-Quad activities, consisting of member-state cooperation with other like-minded partners.
THE DYNAMICS OF THE ENVELOPE SURROUNDING THE PROTOSTAR HH 211 mm

We present a study of the structure and dynamics of the dense gas surrounding the HH 211 mm source, using Very Large Array (VLA) observations of the ammonia (1,1) and (2,2) inversion transitions. We find that the envelope around this Class 0 source has an elongated geometry, extending about 104 AU in the direction perpendicular to the well-known HH 211 jet, and exhibits a velocity distribution consistent with rotation along the major axis. Our VLA observations indicate that the envelope is mostly in virial equilibrium. However, comparing our data with results from previous studies, it appears that the gas within approximately 0.005 pc of the central protostar is undergoing dynamical collapse. The size of this collapsing radius may constrain the amount of mass that can eventually infall into the forming star. We also find that the envelope is mostly internally heated, most probably by radiation from the central protostar. In addition, we detect evidence of outflow–envelope interaction in the ammonia data. These include a velocity gradient in the dense gas along the outflow axis and significant line broadening that is spatially correlated with the jet and could be the result of outflow-induced turbulence in the envelope.
The holographic description of a baryon in non-critical string theory

Thermodynamics functions of dense matter with baryon density have been calculated using AdS/CFT duality. The confining phase of the near-extremal AdS6 background constructed from the intersecting brane configuration has been considered. The obtained results have been compared with the critical ones obtained using the Sakai–Sugimoto or Klebanov–Strassler models. Our results show that at large Nc and low baryon density the baryon–baryon interaction is repulsive as expected. Also a dynamical baryon has been considered in this model and its binding energy has been calculated. Results show that the baryon binding energy for our configuration is roughly 2.74 GeV. Moreover, the mass of quarks that composed the dynamical baryon has been approximated at roughly 372 MeV.
An application of extreme value statistics to the most massive galaxy clusters at low and high redshifts

In this work we present an application of general extreme value statistics (GEV) to very massive single clusters at high and low redshifts. After introd ucing the formalism, we apply this statistics to four very massive high redshift clusters. Tho se clusters comprise ACT-CL J01024915 with a mass of M200m = (2.16± 0.32)× 10 15 M⊙ at a redshift of z = 0.87, SPT-CL J21065844 with a mass of M200m = (1.27± 0.21)× 10 15 M⊙ at z = 1.132 and two clusters found by the XMM-Newton Distant Cluster Project survey: XMMU J2235.32557 with a mass of M200c = (7.3± 1.3)× 10 14 M⊙ located at a redshift z = 1.4 and XMMU J0044.0-2033 having a mass in the range of M200c = (3.5− 5.0)× 10 14 M⊙ at z = 1.579. By relating those systems to their corresponding distribution functions of being the most massive system in a given survey
Breuil-Mézard conjectures for central division algebras

We formulate an analogue of the Breuil-M\'ezard conjecture for the group of units of a central division algebra over a $p$-adic local field, and we prove that it follows from the conjecture for $\mathrm{GL}_n$. To do so we construct a transfer of inertial types and Serre weights between the maximal compact subgroups of these two groups, in terms of Deligne-Lusztig theory, and we prove its compatibility with mod $p$ reduction, via the inertial Jacquet-Langlands correspondence and certain explicit character formulas. We also prove analogous statements for $\ell$-adic coefficients.
Magic-State Distillation in All Prime Dimensions Using Quantum Reed-Muller Codes

We propose families of protocols for magic state distillation -- important components of fault tolerance schemes --- for systems of odd prime dimension. Our protocols utilize quantum Reed-Muller codes with transversal non-Clifford gates. We find that, in higher dimensions, small and effective codes can be used that have no direct analogue in qubit (two-dimensional) systems. We present several concrete protocols, including schemes for three-dimensional (qutrit) and five-dimensional (ququint) systems. The five-dimensional protocol is, by many measures, the best magic state distillation scheme yet discovered. It excels both in terms of error threshold with respect to depolarising noise (36.3%) and the efficiency measure know as "yield", where, for a large region of parameters, it outperforms its qubit counterpart by many orders of magnitude.
The NIR Ca II triplet at low metallicity: Searching for extremely low-metallicity stars in classical dwarf galaxies

The NIR Ca II triplet absorption lines have proven to be an important tool for quantitative spectroscopy of individual red giant branch stars in the Local Group, providing a better understanding of metallicities of stars in the Milky Way and dwarf galaxies and thereby an opportunity to constrain their chemical evolution processes. An interesting puzzle in this field is the significant lack of extremely metal-poor stars, below [Fe/H] = -3, found in classical dwarf galaxies around the Milky Way using this technique. The question arises whether these stars are really absent, or if the empirical Ca II triplet method used to study these systems is biased in the low-metallicity regime. Here we present results of synthetic spectral analysis of the Ca II triplet, that is focused on a better understanding of spectroscopic measurements of low-metallicity giant stars. Our results start to deviate strongly from the widely-used and linear empirical calibrations at [Fe/H] = [Fe/H] >= -4. We subsequently apply this new calibration to current data sets and suggest that the classical dwarf galaxies are not so devoid of extremely low-metallicity stars as was previously thought.