Miracle-dz/UniFAR-FTUs huggingface dataset:
Dreaming awake: disentangling the underlying physics in case of a SUSY-like discovery at the LHC

The purpose of this review is to investigate what kind of physics can be extracted at the LHC, assuming a discovery is made in events with missing transverse momentum, as generically expected in supersymmetry (SUSY) with R-parity conservation. To set the scene, we first discuss the collider phenomenology of the six possible electroweakino benchmark scenarios, as they provide valuable insight into what one might be facing at the LHC. We review the existing methods for mass reconstruction from measured kinematic endpoints in the distributions of suitable variables, e.g., the invariant masses of various sets of visible decay products, as well as the $M_{T2}$ and the $M_2$ types of variables. We propose to extend the application of these methods to the various topologies of fully hadronic final states, possibly with hadronically reconstructed massive bosons (W, Z or h). We test the idea with a simplified simulation of events in the main electroweakino benchmark scenarios. We find that the fully hadronic events allow the complete determination of the relevant mass spectrum. For comparison, we also review the potential of the standard kinematic endpoint methods for final states involving leptons from the decays of (on-shell or off-shell) sleptons. We find that with 300 $fb^{-1}$, the statistics for the leptonic events is very marginal and they look less promising than the fully hadronic channels. This corresponds to a complete reversal of the usual paradigm, where leptonic events comprised the gold-plated SUSY channels. Finally, we put together all available information and summarize what level of understanding of the underlying physics can be achieved. We show that, as a by-product of the mass reconstruction, it is also possible to determine the production cross sections and decay branching ratios, which in turn enable us to pinpoint the underlying model.
The environmental properties of radio-emitting AGN

We study the environmental properties of z 10^{23.5} W Hz^{-1} sr^{-1}$ are twice more likely to be found in clusters with respect to fainter sources (~38% vs ~15%), just as radio-selected AGN with stellar masses $M*>10^{11} M_\odot$ are twice more likely to be found in overdense environments with respect to objects of lower mass (~24% vs ~11%). Comparisons with galaxy samples further suggest that radio-selected AGN of large stellar mass tend to avoid underdense environments more than normal galaxies with the same stellar content. Stellar masses also seem to determine the location of radio-active AGN within clusters: ~100% of the sources found as satellite galaxies have $M* 10^{11} M_\odot$. No different location within the cluster is instead observed for AGN of various radio luminosities. Radio AGN which also emit in the MIR show a marked preference to be found as isolated galaxies (~70%) at variance with those also active in the X-ray which all seem to reside within overdensities. What emerges from our work is a scenario whereby physical processes on sub-pc and kpc scales (e.g. emission respectively related to the AGN and to star formation) are strongly interconnected with the large-scale environment of the AGN itself.
GRADED IDENTITIES FOR THE MATRIX ALGEBRA OF ORDER OVER AN INFINITE FIELD

ABSTRACT The algebra of all square matrices of order over a field has a natural -grading. In this paper, we generalize a result of Vasilovsky about the -graded identities of the algebra . It is shown that, when is an infinite field, all the -graded polynomial identities of follow from the identities: where is the degree of the indeterminate .
Discovery of Pulsation Dropout and Turn-on during the High State of the Accreting X-Ray Pulsar LMC X-4

Two Nuclear Spectroscopic Telescope Array (NuSTAR) observations of the luminous X-ray pulsar LMC X-4 in 2015 October and November captured several bright accretion flares from this source, which has a long history of stable pulse and superorbital behavior. We present a timing analysis of these data in which we detect a rapid pulse “turn-on” in association with the accretion flares, during which the source reaches super-Eddington luminosities. Pulsations, which are normally seen from this source, are found to only occur for approximately one hour before and during the bright flares. Beyond one hour before and after the flares, we find pulsations to be weak or nonexistent, with fractional rms amplitudes of less than 0.05. At the onset of the flare, the pulse profiles exhibit a phase shift of 0.25 cycles that could be associated with a change in the emission geometry. This increase in pulse strength occurring well before the flare cannot be explained by the propeller effect, and potentially offers a connection between the magnetic properties of pulsars that accrete close to their Eddington limits and ultra-luminous X-ray pulsars.
On the Stellar Masses of Giant Clumps in Distant Star-forming Galaxies

We analyze stellar masses of clumps drawn from a compilation of star-forming galaxies at 1.1 < z < 3.6. Comparing clumps selected in different ways, and in lensed or blank field galaxies, we examine the effects of spatial resolution and sensitivity on the inferred stellar masses. Large differences are found, with median stellar masses ranging from for clumps in the often-referenced field galaxies to for fainter clumps selected in deep-field or lensed galaxies. We argue that the clump masses, observed in non-lensed galaxies with a limited spatial resolution of ∼1 kpc, are artificially increased due to the clustering of clumps of smaller mass. Furthermore, we show that the sensitivity threshold used for the clump selection affects the inferred masses even more strongly than resolution, biasing clumps at the low-mass end. Both improved spatial resolution and sensitivity appear to shift the clump stellar mass distribution to lower masses, qualitatively in agreement with clump masses found in recent high-resolution simulations of disk fragmentation. We discuss the nature of the most massive clumps, and we conclude that it is currently not possible to properly establish a meaningful clump stellar mass distribution from observations and to infer the existence and value of a characteristic clump mass scale.
Hypercritical accretion scenario in central compact objects accompanied with an expected neutrino burst

The measurement of the period and period derivative, and the canonical model of dipole radiation have provided a method to estimate the low superficial magnetic fields in the so-called Central Compact Objects (CCOs). In the present work, a scenario is introduced in order to explain the magnetic behavior of such CCOs. Based on magnetohydrodynamic simulations of the post core-collapse supernova phase during the hypercritical accretion episode, we argue that the magnetic field of a newborn neutron star could have been early buried. During this phase, thermal neutrinos are created mainly by the pair annihilation, plasmon decay, photo-neutrino emission and other processes. We study the dynamics of these neutrinos in this environment and also estimate the number expected of the neutrino events with their flavor ratios on Earth. The neutrino burst is the only viable observable that could provide compelling evidence of the hypercritical phase and therefore, the hidden magnetic field mechanism as the most favorable scenario to explain the anomalous low magnetic fields estimated for CCOs.
IVOA Recommendation: VOEvent Transport Protocol Version 2.0

The IVOA VOEvent Recommendation defines a means of describing transient celestial events but, purposely, remains silent on the topic of how those descriptions should be transmitted. This document formalizes a TCP-based protocol for VOEvent transportation that has been in use by members of the VOEvent community for several years and discusses the topology of the event distribution network. It is intended to act as a reference for the production of compliant protocol implementations.
Investigating the effects of operating conditions on the exergetic performance of a pilot-scale spray-drying system

In this study, performance of a pilot scale spray drier was evaluated by exergy analysis method. Performance parameters were investigated for the components of the drying system and overall system. Furthermore, the effects of process conditions such as atomisation pressure, inlet and outlet drying air temperatures on the performance of the spray drier were analyzed. While the most effective system component was determined as heater, atomizer was the most important component with the highest improvement potential rate. Results showed that high inlet and low outlet air temperatures caused high effectiveness for overall system performance.
Submillimeter- and Millimeter-Wavelength Observations of SiO and HCN in Circumstellar Envelopes of AGB Stars

We report molecular line observations with the Heinrich Hertz Submillimeter Telescope of a sample of 30 asymptotic giant branch stars with spectral types M, S, and C. Measured lines include SiO J = 5-4, 8-7, 10-9, and HCN J = 3-2 and 4-3 transitions, which arise from energy levels ranging from 26 to 115 K above ground. The observed transitions were detected in almost all stars observed, regardless of spectral type. The HCN J = 3-2 and 4-3 lines in the M stars are bright compared with previous observations of the J = 1-0 line. We calculated emergent spectra for model circumstellar envelopes and compare these with the observed line intensity ratios. We conclude that (1) the HCN line intensity ratios for the M stars are inconsistent with chemical models in which HCN is produced via photochemistry in the outer circumstellar envelope. HCN must be formed by a nonequilibrium chemical process in the inner envelope or extended stellar atmosphere. (2) The HCN/SiO intensity ratios of lines with similar excitation energies clearly separate the carbon stars from the M and S stars. The M and S stars show a trend of increasing HCN/SiO intensity ratios with increasing mass-loss rate. (3) These data support the idea that pulsation-driven shocks result in the formation of organic molecules like HCN in the envelopes of M stars. Observations of these molecules could give useful constraints on hydrodynamic models for stellar mass loss driven by pulsational shocks in the stellar atmosphere. We detected emission from vibrationally excited HCN in the v = (0,11c,0), J = 3-2 and 4-3 transitions toward four carbon stars. In one star, V Cyg, the lines are strong and narrow, and are most likely a result of maser amplification.
Circumstellar CO in metal-poor stellar winds: the highly irradiated globular cluster star 47 Tucanae V3

We report the first detection of circumstellar CO in a globular cluster. Observations with ALMA have detected the CO J=3-2 and SiO v=1 J=8-7 transitions at 345 and 344 GHz, respectively, around V3 in 47 Tucanae (NGC 104; [Fe/H] = -0.72 dex), a star on the asymptotic giant branch. The CO line is detected at 7 sigma at a rest velocity v_LSR = -40.6 km/s and expansion velocity of 3.2 +/- ~0.4 km/s. The brighter, asymmetric SiO line may indicate a circumstellar maser. The stellar wind is slow compared to similar Galactic stars, but the dust opacity remains similar to Galactic comparisons. We suggest that the mass-loss rate is set by the levitation of material into the circumstellar environment by pulsations, but that the terminal wind-expansion velocity is determined by radiation pressure on the dust: a pulsation-enhanced dust-driven wind. We suggest the metal-poor nature of the star decreases the grain size, slowing the wind and increasing its density and opacity. Metallic alloys at high altitudes above the photosphere could also provide an opacity increase. The CO line is weaker than expected from Galactic AGB stars, but its strength confirms a model that includes CO dissociation by the strong interstellar radiation field present inside globular clusters.
Extinction in the Star Cluster SAI 113 and Galactic Structure in Carina

Photometric CCD UB VIC photometry obtained for 4860 stars surrounding the embedded southern cluster SAI 113 (Skiff 8) is used to examine the reddening in the field and derive the distance to the cluster and nearby van Genderen 1. Spectroscopic color excesses for bright cluster stars, photometric reddenings for A3 dwarfs, and dereddening of cluster stars imply that the reddening and extinction laws match results derived for other young clusters in Carina: and . SAI 113 displays features that may be linked to a history of dynamical interactions among member stars: possible circumstellar reddening and rapid rotation of late B-type members, ringlike features in star density, and a compact core, with most stars distributed randomly across the field. The group van Genderen 1 resembles a stellar asterism, with potential members distributed randomly across the field. Distances of 3.90 ± 0.19 kpc and 2.49 ± 0.09 kpc are derived for SAI 113 and van Genderen 1, respectively, with variable reddenings ranging from 0.84 to 1.29 and 0.23 to 1.28. The SRC variables CK Car and EV Car may be outlying members of van Genderen 1, thereby of use for calibrating the period–luminosity relation for pulsating M supergiants. More importantly, the anomalous reddening and extinction evident in Carina and nearby regions of the Galactic plane in the fourth quadrant impact the mapping of spiral structure from young open clusters. The distribution of spiral arms in the fourth quadrant may be significantly different from how it is often portrayed.
TASI Lectures on Indirect Searches For Dark Matter

In these lectures, I describe a variety of efforts to identify or constrain the identity of dark matter by detecting the annihilation or decay products of these particles, or their effects. After reviewing the motivation for indirect searches, I discuss what we have learned about dark matter from observations of gamma rays, cosmic rays and neutrinos, as well as the cosmic microwave background. Measurements such as these have been used to significantly constrain a wide range of thermal relic dark matter candidates, in particular those with masses below a few hundred GeV. I also discuss a number of anomalies and excesses that have been interpreted as possible signals of dark matter, including the Galactic Center gamma-ray excess, the cosmic-ray antiproton excess, the cosmic-ray positron excess, and the 3.5 keV line. These lectures were originally presented as part of the 2018 Theoretical Advanced Study Institute (TASI) summer school on "Theory in an Era of Data". Although intended for advanced graduate students, these lectures may be useful for a wide range of physicists, astrophysicists and astronomers who wish to get an overview of the current state of indirect searches for dark matter.
Kinetic–MHD simulations of gyroresonance instability driven by CR pressure anisotropy

The transport of cosmic rays (CRs) is crucial for the understanding of almost all high-energy phenomena. Both pre-existing large-scale magnetohydrodynamic (MHD) turbulence and locally generated turbulence through plasma instabilities are important for the CR propagation in astrophysical media. The potential role of the resonant instability triggered by CR pressure anisotropy to regulate the parallel spatial diffusion of low-energy CRs ($\lesssim 100$ GeV) in the interstellar and intracluster medium of galaxies (ISM and ICM) has been showed in previous theoretical works. This work aims to study the gyroresonance instability via direct numerical simulations, in order to access quantitatively the wave-particle scattering rates. For this we employ a 1D PIC-MHD code to follow the growth and saturation of the gyroresonance instability. We extract from the simulations the pitch-angle diffusion coefficient $D_{\mu\mu}$ produced by the instability during the linear and saturation phases, and a very good agreement (within a factor of 3) is found with the values predicted by the quasilinear theory (QLT). Our results support the applicability of the QLT for modeling the scattering of low-energy CRs by the gyroresonance instability in the complex interplay between this instability and the large-scale MHD turbulence.
The Hartree ensemble approximation revisited: The "symmetric phase"

The Hartree ensemble approximation is studied in the ``symmetric phase'' of 1+1 dimensional lambda phi^4 theory. In comparison with the ``broken phase'' studied previously, it is shown that the dynamical evolution of observables such as the particle distribution, energy exchange and auto-correlation functions, is substantially slower. Approximate thermalization is found only for relatively large energy densities and couplings.
Non-Invertibility of spectral x-ray photon counting data with pileup

-In the Alvarez-Macovski method [R.E. Alvarez and A. Macovski, Phys. Med. Biol., 1976, 733-744], the attenuation coefficient is approximated as a linear combination of functions of energy multiplied by coefficients that depend on the material composition at points within the object. The method then computes the line integrals of the basis set coefficient from measurements with different x-ray spectra. This paper shows that the transformation from photon counting detector data with pileup to the line integrals can become ill-conditioned under some circumstances leading to highly increased noise. Methods: An idealized model that includes pileup and quantum noise is used. The noise variance of the line integral estimates is computed using the Cram{\`e}r-Rao lower bound (CRLB). The CRLB is computed as a function of object thickness for photon counting detector data with three and four bin pulse height analysis (PHA) and low and high pileup. Results: With four bin PHA data the transformation is well conditioned with either high or low pileup. With three bin PHA and high pileup, the transformation becomes ill-conditioned for specific values of object attenuation. At these values the CRLB variance increases by approximately 10 5 compared with the four bin PHA or low pileup results. The condition number of the forward transformation matrix also shows a spike at those attenuation values. Conclusion: Designers of systems using counting detectors should study the stability of the line integral estimator output with their data.
Temperature control of electromigration to form gold nanogap junctions

Controlled electromigration of gold nanowires of different cross-sectional areas to form nanogap junctions is studied using a feedback method. A linear correlation between the cross-sectional area of the gold nanowires and the power dissipated in the junction during electromigration is observed, indicating that the feedback mechanism operates primarily by controlling the temperature of the junction during electromigration. We also show that the role of the external feedback circuit is to prevent thermal runaway; minimization of series resistance allows controlled electromigration to a significant range of junction resistances with a simple voltage ramp.
Quantum Electrodynamics on background external fields

The quantum electrodynamics in presence of background external fields is developed. Modern methods of local quantum physics allow to formulate the theory on arbitrarily strong possibly time-dependent external fields. Non-linear observables which depend only locally on the external field are constructed. The tools necessary for this formulation, the parametrices of the Dirac operator, are investigated.
Effect of inner Lindblad resonance on spiral density waves propagation in disc galaxies: reflection over absorption

Interaction of spiral density waves with stars in the vicinity of the inner Lindblad resonance in galactic discs is investigated using the linear perturbation theory and the leading orders in the epicyclic and WKB approximations. In analogy with shear flows in hydrodynamics, we conjecture that a weak nonlinearity in a narrow resonance region modifies the standard (Landau-Lin) bypass rule of the singularity to the integration in the principal value sense. This indeed leads to the reflection of the spiral wave instead of absorption, but the detailed picture looks awkward: the intervals of the wave weakening alternate with the intervals of the wave growth, so that the net absorption is absent. Incidentally, we rectify the result concerning leading spiral waves obtained earlier for the standard bypass rule.
Mathematical models of Markovian dephasing

We develop a notion of dephasing under the action of a quantum Markov semigroup in terms of convergence of operators to a block-diagonal form determined by irreducible invariant subspaces. If the latter are all one-dimensional, we say the dephasing is maximal. With this definition, we show that a key necessary requirement on the Lindblad generator is bistochasticity, and focus on characterizing whether a maximally dephasing evolution may be described in terms of a unitary dilation with only classical noise, as opposed to a genuine non-commutative Hudson–Parthasarathy dilation. To this end, we make use of a seminal result of Kümmerer and Maassen on the class of commutative dilations of quantum Markov semigroups. In particular, we introduce an intrinsic quantity constructed from the generator, the Hamiltonian obstruction, which vanishes if and only if the latter admits a self-adjoint representation and quantifies the hindrance to having a classical diffusive noise model.
A Collision of Subclusters in Abell 754

We present direct evidence of a collision of subclusters in the galaxy cluster Abell 754. Our comparison of new optical data and archival ROSAT PSPC X-ray data reveals three collision signatures predicted by n-body/hydrodynamical simulations of hierarchical cluster evolution. First, there is strong evidence of a nonhydrostatic process; neither of the two major clumps in the galaxy distribution lies on the off-center peak of the X-ray emission from the intracluster gas. Second, the peak of the X-ray emission is elongated perpendicular to the collision axis defined by connecting the centroids of the two galaxy clumps. Third, there is evidence of compression-heated gas; one of A754's two X-ray temperature components (Henry & Briel 1995) is among the hottest observed in any cluster and hotter than that inferred from the velocity dispersion of the associated galaxy clump. These signatures are consistent with the qualitative features of simulations (Evrard 1990a, b) in which two subclusters have collided in the plane of the sky during the last ~1 Gyr. The detection of such collisions is crucial for understanding both the dynamics of individual clusters and the underlying cosmology. First, for systems like A754, estimating the cluster X-ray mass from assumptions of hydrostatic equilibrium and isothermality is incorrect and may produce the discrepancies sometimes found between X-ray masses and those derived from gravitational lens models (Babul & Miralda-Escudé 1994). Second, the fraction of nearby clusters in which subclusters have collided in the last ~1 Gyr is especially sensitive to the mean mass density parameter Ω0 (see Richstone, Loeb, & Turner 1992; Evrard et al. 1993; Lacey & Cole 1993). As we show for A754, we now have the means to identify recent collisions. With a large, well-defined cluster sample, it will be possible to place a new and powerful constraint on cosmological models.