cometadata/datacite-rtg-text-other-reclassification-records huggingface dataset:
The thermalisation of massive galaxy clusters
Creators: name: Sereno, Mauro
name: Lovisari, Lorenzo
name: Cui, Weiguang
name: Schellenberger, Gerrit
Publisher: name: arXiv
Year: 2021
Subjects: subject: Cosmology and Nongalactic Astrophysics (astro-ph.CO)
subject: FOS: Physical sciences

description: In the hierarchical scenario of structure formation, galaxy clusters are the ultimate virialised products in mass and time. Hot baryons in the intracluster medium (ICM) and cold baryons in galaxies inhabit a dark matter dominated halo. Internal processes, accretion, and mergers can perturb the equilibrium, which is established only at later times. However, the cosmic time when thermalisation is effective is still to be assessed. Here we show that massive clusters in the observed universe attained an advanced thermal equilibrium $\sim~1.8~\text{Gyr}$ ago, at redshift $z =0.14\pm0.06$, when the universe was $11.7\pm0.7~\text{Gyr}$ old. Hot gas is mostly thermalised after the time when cosmic densities of matter and dark energy match. We find in a statistically nearly complete and homogeneous sample of 120 clusters from the {\it Planck} Early Sunyaev-Zel'dovich (ESZ) sample that the kinetic energy traced by the galaxy velocity dispersion is a faithful probe of the gravitational energy since a look back time of at least $\sim5.4~\text{Gyr}$, whereas the efficiency of hot gas in converting kinetic to thermal energy, as measured through X-ray observations in the core-excised area within $r_{500}$, steadily increases with time. The evolution is detected at the $\sim 98$ per cent probability level. Our results demonstrate that halo mass accretion history plays a larger role for cluster thermal equilibrium than radiative physics. The evolution of hot gas is strictly connected to the cosmic structure formation.
description: 10 pages, 3 figures, in press on MNRAS
Finite torsors over strongly $F$-regular singularities
Creators: name: Carvajal-Rojas, Javier
Publisher: name: arXiv
Year: 2017
Subjects: subject: Algebraic Geometry (math.AG)
subject: Commutative Algebra (math.AC)
subject: FOS: Mathematics
subject: 13A35, 13A50, 14B05, 14L15, 14L30, 16T05

description: We investigate finite torsors over big opens of spectra of strongly $F$-regular germs that do not extend to torsors over the whole spectrum. Let $(R,\mathfrak{m},k)$ be a strongly $F$-regular $k$-germ where $k$ is an algebraically closed field of characteristic $p>0$. We prove the existence of a finite local cover $R \subset R^{\star}$ so that $R^{\star}$ is a strongly $F$-regular $k$-germ and: for all finite algebraic groups $G/k$ with solvable neutral component, every $G$-torsor over a big open of $\mathrm{Spec} R^{\star}$ extends to a $G$-torsor everywhere. To achieve this, we obtain a generalized transformation rule for the $F$-signature under finite local extensions. Such formula is used to show that that the torsion of $\mathrm{Cl} R$ is bounded by $1/s(R)$. By taking cones, we conclude that the Picard group of globally $F$-regular varieties is torsion-free. Likewise, it shows that canonical covers of $\mathbb{Q}$-Gorenstein strongly $F$-regular singularities are strongly $F$-regular.
description: 30 pages. Final version accepted to EPIGA
Appendix to Modal and Symbolic Trace Logic
Creators: name: Steinhöfel, Dominic
name: Hähnle, Reiner
Publisher: name: Zenodo
Year: 2021
Subjects: Program Verification, Relational Verification, Trace Semantics, Symbolic Traces, Symbolic State Subsumption, Symbolic Execution

description: This is the online appendix to the paper "Modal and Symbolic Trace Logic" submitted to the Journal of Logic and Algebraic Methods (JLAMP).
Morphology of radio relics II: Properties of polarised emission
Creators: name: Domínguez-Fernández, P.
name: Brüggen, M.
name: Vazza, F.
name: Hoeft, M.
name: Banda-Barragán, W. E.
name: Rajpurohit, K.
name: Wittor, D.
name: Mignone, A.
name: Mukherjee, D.
name: Vaidya, B.
Publisher: name: arXiv
Year: 2021
Subjects: subject: High Energy Astrophysical Phenomena (astro-ph.HE)
subject: FOS: Physical sciences

description: Radio relics are diffuse radio sources in galaxy clusters that are associated with merger shock waves. Detailed observations of radio relics in total intensity and in polarisation show complex structures on kiloparsec scales. The relation between the observed features and the underlying morphology of the magnetic field is not clear. Using three-dimensional magneto-hydrodynamical simulations, we study the polarised emission produced by a shock wave that propagates through a turbulent medium that resembles the intracluster medium. We model the polarised synchrotron emission on the basis of diffusive shock acceleration of cosmic-ray electrons. We find that the synchrotron emission produced in a shocked turbulent medium can reproduce some of the observed features in radio relics. Shock compression can give rise to a high polarisation fraction at the shock front and a partial alignment of the polarisation $E$-vectors with the shock normal. Our work confirms that radio relics can also be formed in an environment with a tangled magnetic field. We also discuss the effect of Faraday Rotation intrinsic to the source, and how our results depend on the angular resolution of observations.
description: Accepted for publication in MNRAS, 22 pages, 23 figures
Optimal Scheduling of Multiple Sensors over Lossy and Bandwidth Limited Channels
Creators: name: Wu, Shuang
name: Ding, Kemi
name: Cheng, Peng
name: Shi, Ling
Publisher: name: arXiv
Year: 2018
Subjects: subject: Systems and Control (eess.SY)
subject: FOS: Electrical engineering, electronic engineering, information engineering

description: This work considers the sensor scheduling for multiple dynamic processes. We consider $n$ linear dynamic processes, the state of each process is measured by a sensor, which transmits their local state estimates over wireless channels to a remote estimator with certain communication costs. In each time step, only a portion of the sensors is allowed to transmit data to the remote estimator and the packet might be lost due to unreliability of the wireless channels. Our goal is to find a scheduling policy which coordinates the sensors in a centralized manner to minimize the total expected estimation error of the remote estimator and the communication costs. We formulate the problem as a Markov decision process. We develop an algorithm to check whether there exists a deterministic stationary optimal policy. We show the optimality of monotone policies, which saves computational effort of finding an optimal policy and facilitates practical implementation. Nevertheless, obtaining an exact optimal policy still suffers from curse of dimensionality when the number of processes are large. We further provide an index-based heuristics to avoid brute force computation. Numerical examples are presented to illustrate our theoretical results.
description: Correct version
The snowmelt hydrology of a small alpine watershed
Creators: name: Jordan, Robert Peter
Publisher: name: University of British Columbia
Year: 2010

description: A study of the mass and energy balance of a small alpine watershed was conducted in the summer of 1976, with the aim of applying snow hydrology theory at a watershed scale in a remote environment. The field area is in the Coast Mountains near Bralorne, B.C. The study concentrates on the measurement of snow ablation, the movement of meltwater within the snowpack, the generation of stream runoff during and following snowmelt, and the energy balance at the snow surface. Standard methods for measuring snow ablation, used in the fields of glaciology and snow surveying, are analysed in terms of their accuracy and precision, and the sampling densities required for their application. Simple field instrumentation is used to study the movement of meltwater in the snowpack, and this is analysed in terms of the theory of flow through a porous medium. The movement of meltwater through the snow is found to be the most important process affecting the shape and timing of the stream hydrograph. The movement of water along the base of the snowpack and through the soil also has an influence on the shape of the hydrograph. In the alpine meadow environment studied, saturated soil and ice covering ground beneath the snow contribute to a rapid stream response. A water balance is calculated for the watershed, based on measurement of stream discharge, snow ablation, and precipitation, and on climatological estimates of evaporation. An energy balance for the season is also calculated, supported by microclimatological measurements for part of the season. Radiation is found to contribute 90% of the energy required for snowmelt, and a simple model for the calculation of net radiation from solar radiation is developed. Empirical methods are found to be suitable for the calculation of turbulent energy transfer over snow. Some observations are made of the water balance in the late summer, and these indicate that water stored in the soil during snowmelt is important in maintaining streamflow later in the season.
Analysis of the Effect of Speed Limit Increases on Accident-Injury Severities
Creators: name: Malyshkina, Nataliya V.
name: Mannering, Fred L.
Publisher: name: arXiv
Year: 2008
Subjects: subject: Applications (stat.AP)
subject: FOS: Computer and information sciences

description: The influence of speed limits on roadway safety has been a subject of continuous debate in the State of Indiana and nationwide. In Indiana, highway-related accidents result in about 900 fatalities and forty thousand injuries annually and place an incredible social and economic burden on the state. Still, speed limits posted on highways and other roads are routinely exceeded as individual drivers try to balance safety, mobility (speed), and the risks and penalties associated with law enforcement efforts. The speed-limit/safety issue has been a matter of considerable concern in Indiana since the state raised its speed limits on rural interstates and selected multilane highways on July 1, 2005. In this paper, the influence of the posted speed limit on the severity of vehicle accidents is studied using Indiana accident data from 2004 (the year before speed limits were raised) and 2006 (the year after speed limits were raised on rural interstates and some multi-lane non-interstate routes). Statistical models of the injury severity of different types of accidents on various roadway classes were estimated. The results of the model estimations showed that, for the speed limit ranges currently used, speed limits did not have a statistically significant effect on the severity of accidents on interstate highways. However, for some non-interstate highways, higher speed limits were found to be associated with higher accident severities - suggesting that future speed limit changes, on non-interstate highways in particular, need to be carefully assessed on a case-by-case basis.
description: 14 pages, 2 tables, accepted for publication in Transportation Research Record
Asymptotic behavior of solutions to the generalized KdV-Burgers equation with slowly decaying data
Creators: name: Fukuda, Ikki
Publisher: name: arXiv
Year: 2018
Subjects: subject: Analysis of PDEs (math.AP)
subject: FOS: Mathematics
subject: 35B40, 35Q53

description: We consider the asymptotic behavior of the global solutions to the initial value problem for the generalized KdV-Burgers equation. It is known that the solution to this problem converges to a self-similar solution to the Burgers equation called a nonlinear diffusion wave. In this paper, we derive the optimal asymptotic rate to the nonlinear diffusion wave when the initial data decays slowly at spatial infinity. In particular, we investigate that how the change of the decay rate of the initial value affects the asymptotic rate to the nonlinear diffusion wave.
description: 32 pages
Mid-infrared interferometry of massive young stellar objects
Creators: name: Linz, H.
name: Stecklum, B.
name: Follert, R.
name: Henning, Th.
name: van Boekel, R.
name: Men'shchikov, A.
name: Pascucci, I.
name: Feldt, M.
Publisher: name: arXiv
Year: 2008
Subjects: subject: Astrophysics (astro-ph)
subject: FOS: Physical sciences

description: The very inner structure of massive young stellar objects (YSOs) is difficult to trace. With conventional observational methods we identify structures still several hundreds of AU in size. However, the (proto-)stellar growth takes place at the innermost regions (<100 AU) where the actual mass transfer onto the forming high-mass star occurs. We present results from our programme toward massive YSOs at the VLTI, utilising the two-element interferometer MIDI. To date, we observed 10 well-known massive YSOs down to scales of 20 mas (typically corresponding to 20 - 40 AU for our targets) in the 8-13 micron region. We clearly resolve these objects which results in low visibilities and sizes in the order of 30-50 mas. For two objects, we show results of our modelling. We demonstrate that the MIDI data can reveal decisive structure information for massive YSOs. They are often pivotal in order to resolve ambiguities still immanent in model parameters derived from sole SED fitting.
description: 6 pages, 5 figures, necessary style files iopams.sty, jpconf11.clo, and jpconf.cls included; contribution for the conference "The Universe under the Microscope" (AHAR 2008), held in Bad Honnef (Germany) in April 2008, to be published in Journal of Physics: Conference Series by Institute of Physics Publishing, R. Schoedel, A. Eckart, S. Pfalzner, and E. Ros (eds.)
The SEDIGISM survey: The influence of spiral arms on the molecular gas distribution of the inner Milky Way
Creators: name: Colombo, D.
name: Duarte-Cabral, A.
name: Pettitt, A. R.
name: Urquhart, J. S.
name: Wyrowski, F.
name: Csengeri, T.
name: Neralwar, K. R.
name: Schuller, F.
name: Menten, K. M.
name: Anderson, L.
name: Barnes, P.
name: Beuther, H.
name: Bronfman, L.
name: Eden, D.
name: Ginsburg, A.
name: Henning, T.
name: Koenig, C.
name: Lee, M. -Y.
name: Mattern, M.
name: Medina, S.
name: Ragan, S. E.
name: Rigby, A. J.
name: Sanchez-Monge, A.
name: Traficante, A.
name: Yang, A. Y.
name: Wienen, M.
Publisher: name: arXiv
Year: 2021
Subjects: subject: Astrophysics of Galaxies (astro-ph.GA)
subject: FOS: Physical sciences

description: The morphology of the Milky Way is still a matter of debate. In order to shed light on uncertainties surrounding the structure of the Galaxy, in this paper, we study the imprint of spiral arms on the distribution and properties of its molecular gas. To do so, we take full advantage of the SEDIGISM survey that observed a large area of the inner Galaxy in the $^{13}$CO(2-1) line at an angular resolution of 28". We analyse the influences of the spiral arms by considering the features of the molecular gas emission as a whole across the longitude-velocity map built from the full survey. Additionally, we examine the properties of the molecular clouds in the spiral arms compared to the properties of their counterparts in the inter-arm regions. Through flux and luminosity probability distribution functions, we find that the molecular gas emission associated with the spiral arms does not differ significantly from the emission between the arms. On average, spiral arms show masses per unit length of $\sim10^5-10^6$ M$_{\odot} $kpc$^{-1}$. This is similar to values inferred from data sets in which emission distributions were segmented into molecular clouds. By examining the cloud distribution across the Galactic plane, we infer that the molecular mass in the spiral arms is a factor of 1.5 higher than that of the inter-arm medium, similar to what is found for other spiral galaxies in the local Universe. We observe that only the distributions of cloud mass surface densities and aspect ratio in the spiral arms show significant differences compared to those of the inter-arm medium; other observed differences appear instead to be driven by a distance bias. By comparing our results with simulations and observations of nearby galaxies, we conclude that the measured quantities would classify the Milky Way as a flocculent spiral galaxy, rather than as a grand-design one.
description: Accepted for publication in A&A. 38 pages (17 of Appendices), 26 figures, 7 tables. The updated SEDIGISM cloud catalogue, containing spiral arm association information, will be available as part of the SEDIGISM database ( https://sedigism.mpifr-bonn.mpg.de/index.html )
Learning Optimal Scheduling Policy for Remote State Estimation under Uncertain Channel Condition
Creators: name: Wu, Shuang
name: Ren, Xiaoqiang
name: Jia, Qing-Shan
name: Johansson, Karl Henrik
name: Shi, Ling
Publisher: name: arXiv
Year: 2018
Subjects: subject: Systems and Control (eess.SY)
subject: FOS: Electrical engineering, electronic engineering, information engineering

description: We consider optimal sensor scheduling with unknown communication channel statistics. We formulate two types of scheduling problems with the communication rate being a soft or hard constraint, respectively. We first present some structural results on the optimal scheduling policy using dynamic programming and assuming the channel statistics is known. We prove that the Q-factor is monotonic and submodular, which leads to the threshold-like structures in both types of problems. Then we develop a stochastic approximation and parameter learning frameworks to deal with the two scheduling problems with unknown channel statistics. We utilize their structures to design specialized learning algorithms. We prove the convergence of these algorithms. Performance improvement compared with the standard Q-learning algorithm is shown through numerical examples.
description: Full Version
Dynamical dark energy from extra dimensions
Creators: name: Baukh, V.
name: Zhuk, A.
Publisher: name: arXiv
Year: 2008
Subjects: subject: Astrophysics (astro-ph)
subject: General Relativity and Quantum Cosmology (gr-qc)
subject: High Energy Physics - Phenomenology (hep-ph)
subject: FOS: Physical sciences

description: We consider multidimensional cosmological model with a higher-dimensional product manifold M = R x R^{d_0} x H^{d_1}/Γwhere R^{d_0} is d_0-dimensional Ricci-flat external (our) space and H^{d_1}/Γis d_1-dimensional compact hyperbolic internal space. M2-brane solution for this model has the stage of accelerating expansion of the external space. We apply this model to explain the late time acceleration of our Universe. Recent observational data (the Hubble parameter at the present time and the redshift when the deceleration parameter changes its sign) fix fully all free parameters of the model. As a result, we find that considered model has too big size of the internal space at the present time and variation of the effective four-dimensional fine structure constant strongly exceeds the observational limits.
description: 5 pages, 3 figures, LaTex, a few remarks and reference added
Cooling-Induced Vortex Decay in Keplerian Disks
Creators: name: Fung, Jeffrey
name: Ono, Tomohiro
Publisher: name: arXiv
Year: 2021
Subjects: subject: Earth and Planetary Astrophysics (astro-ph.EP)
subject: FOS: Physical sciences

description: Vortices are readily produced by hydrodynamical instabilities, such as the Rossby wave instability, in protoplanetary disks. However, large-scale asymmetries indicative of dust-trapping vortices are uncommon in sub-millimeter continuum observations. One possible explanation is that vortices have short lifetimes. In this paper, we explore how radiative cooling can lead to vortex decay. Elliptical vortices in Keplerian disks go through adiabatic heating and cooling cycles. Radiative cooling modifies these cycles and generates baroclinicity that changes the potential vorticity of the vortex. We show that the net effect is typically a spin down, or decay, of the vortex for a sub-adiabatic radial stratification. We perform a series of two-dimensional shearing box simulations, varying the gas cooling (or relaxation) time, $t_{\rm cool}$, and initial vortex strength. We measure the vortex decay half-life, $t_{\rm half}$, and find that it can be roughly predicted by the timescale ratio $t_{\rm cool}/t_{\rm turn}$, where $t_{\rm turn}$ is the vortex turnaround time. Decay is slow in both the isothermal ($t_{\rm cool}\ll t_{\rm turn}$) and adiabatic ($t_{\rm cool}\gg t_{\rm turn}$) limits; it is fastest when $t_{\rm cool}\sim0.1\,t_{\rm turn}$, where $t_{\rm half}$ is as short as $\sim300$ orbits. At tens of au where disk rings are typically found, $t_{\rm turn}$ is likely much longer than $t_{\rm cool}$, potentially placing vortices in the fast decay regime.
description: Accepted to ApJ
Max-Min Fair Sensor Scheduling: Game-theoretic Perspective and Algorithmic Solution
Creators: name: Wu, Shuang
name: Ren, Xiaoqiang
name: Hong, Yiguang
name: Shi, Ling
Publisher: name: arXiv
Year: 2019
Subjects: subject: Systems and Control (eess.SY)
subject: FOS: Electrical engineering, electronic engineering, information engineering

description: We consider the design of a fair sensor schedule for a number of sensors monitoring different linear time-invariant processes. The largest average remote estimation error among all processes is to be minimized. We first consider a general setup for the max-min fair allocation problem. By reformulating the problem as its equivalent form, we transform the fair resource allocation problem into a zero-sum game between a "judge" and a resource allocator. We propose an equilibrium seeking procedure and show that there exists a unique Nash equilibrium in pure strategy for this game. We then apply the result to the sensor scheduling problem and show that the max-min fair sensor scheduling policy can be achieved.
LeMMINGs. III. The e-MERLIN Legacy Survey of the Palomar sample. Exploring the origin of nuclear radio emission in active and inactive galaxies through the [O III] -- radio connection
Creators: name: Baldi, R. D.
name: Williams, D. R. A.
name: Beswick, R. J.
name: McHardy, I.
name: Dullo, B. T.
name: Knapen, J. H.
name: Zanisi, L.
name: Argo, M. K.
name: Aalto, S.
name: Alberdi, A.
name: Baan, W. A.
name: Bendo, G. J.
name: Fenech, D. M.
name: Green, D. A.
name: Klöckner, H. -R.
name: Körding, E.
name: Maccarone, T. J.
name: Marcaide, J. M.
name: Mutie, I.
name: Panessa, F.
name: Pérez-Torres, M. A.
name: Romero-Cañizales, C.
name: Saikia, D. J.
name: Saikia, P.
name: Shankar, F.
name: Spencer, R. E.
name: Stevens, I. R.
name: Uttley, P.
name: Brinks, E.
name: Corbel, S.
name: Martí-Vidal, I.
name: Mundell, C. G.
name: Pahari, M.
name: Ward, M. J.
Publisher: name: arXiv
Year: 2021
Subjects: subject: Astrophysics of Galaxies (astro-ph.GA)
subject: High Energy Astrophysical Phenomena (astro-ph.HE)
subject: FOS: Physical sciences

description: What determines the nuclear radio emission in local galaxies? We combine optical [O III] line emission, robust black hole (BH) mass estimates, and high-resolution e-MERLIN 1.5-GHz data, from the LeMMINGs survey, of a statistically-complete sample of 280 nearby, optically active (LINER and Seyfert) and inactive HII and Absorption line galaxies [ALG]) galaxies. Using [O III] luminosity ($L_{\rm [O~III]}$) as a proxy for the accretion power, local galaxies follow distinct sequences in the optical-radio planes of BH activity, which suggest different origins of the nuclear radio emission for the optical classes. The 1.5-GHz radio luminosity of their parsec-scale cores ($L_{\rm core}$) is found to scale with BH mass ($M_{\rm BH}$) and [O~III] luminosity. Below $M_{\rm BH} \sim$10$^{6.5}$ M$_{\odot}$, stellar processes from non-jetted HII galaxies dominate with $L_{\rm core} \propto M_{\rm BH}^{0.61\pm0.33}$ and $L_{\rm core} \propto L_{\rm [O~III]}^{0.79\pm0.30}$. Above $M_{\rm BH} \sim$10$^{6.5}$ M$_{\odot}$, accretion-driven processes dominate with $L_{\rm core} \propto M_{\rm BH}^{1.5-1.65}$ and $L_{\rm core} \propto L_{\rm [O~III]}^{0.99-1.31}$ for active galaxies: radio-quiet/loud LINERs, Seyferts and jetted HII galaxies always display (although low) signatures of radio-emitting BH activity, with $L_{\rm 1.5\, GHz}\gtrsim$10$^{19.8}$ W Hz$^{-1}$ and $M_{\rm BH}\gtrsim10^{7}$ M$_{\odot}$, on a broad range of Eddington-scaled accretion rates ($\dot{m}$). Radio-quiet and radio-loud LINERs are powered by low-$\dot{m}$ discs launching sub-relativistic and relativistic jets, respectively. Low-power slow jets and disc/corona winds from moderately high to high-$\dot{m}$ discs account for the compact and edge-brightened jets of Seyferts, respectively. Jetted HII galaxies may host weakly active BHs. Fuel-starved BHs and recurrent activity account for ALG properties. [abridged]
description: Accpeted for publication on MNRAS (27 pages, 9 Figures, 3 Tables, Appendix A)
Asymptotic stability and stability switching for a system of delay differential equations
Creators: name: Saito, Wataru
name: Fukuda, Ikki
Publisher: name: arXiv
Year: 2019
Subjects: subject: Dynamical Systems (math.DS)
subject: FOS: Mathematics
subject: 34K20, 34K25, 93C23

description: In this paper, we consider the asymptotic stability for a system of linear delay differential equations. By analysing of the characteristic equation in detail, we have established the necessary and sufficient condition for the asymptotic stability for the zero solution of the system including the stability switching which describe the transition between stability and instability.
description: 6pages
Radial profiles of lensed $z \sim 1$ galaxies on sub-kiloparsec scales
Creators: name: Nagy, David
name: Dessauges-Zavadsky, Miroslava
name: Richard, Johan
name: Schaerer, Daniel
name: Combes, Françoise
name: Messa, Matteo
name: Chisholm, John
Publisher: name: arXiv
Year: 2021
Subjects: subject: Astrophysics of Galaxies (astro-ph.GA)
subject: FOS: Physical sciences

description: We study the spatially resolved physical properties of the Cosmic Snake arc in MACS J1206.2-0847 and the arc in Abell 0521 (A521). These are two strongly lensed galaxies at redshifts $z=1.036$ and $z=1.044$. We used observations of the Hubble Space Telescope (HST) and the Atacama Large Millimeter/submillimeter Array (ALMA). The former gives access to the star formation rate (SFR) and stellar mass ($M_\star$), and the latter to the H$_2$ molecular gas mass ($M_{\mathrm{mol}}$). HST and ALMA observations have similar angular resolutions of $0.15^{\prime \prime}-0.2^{\prime \prime}$, which with the help of strong gravitational lensing enable us to reach spatial resolutions down to $\sim 30\,\mathrm{pc}$ and $\sim 100\,\mathrm{pc}$ in these two galaxies, respectively. These resolutions are close to the resolution of observations of nearby galaxies. We study the radial profiles of SFR, $M_\star$, and $M_{\mathrm{mol}}$ surface densities of these high-redshift galaxies and compare the corresponding exponential scale lengths with those of local galaxies. We find that the scale lengths in the Cosmic Snake are about $0.5\,\mathrm{kpc}-1.5\,\mathrm{kpc}$, and they are 3 to 10 times larger in A521. This is a significant difference knowing that the two galaxies have comparable integrated properties. These high-redshift scale lengths are nevertheless comparable to those of local galaxies, which cover a wide distribution. The particularity of our high-redshift radial profiles is the normalisation of the $M_{\mathrm{mol}}$ surface density profiles ($ΣM_{\mathrm{mol}}$), which are offset by up to a factor of 20 with respect to the profiles of $z=0$ counterparts. The SFR surface density profiles are also offset by the same factor as $ΣM_{\mathrm{mol}}$, as expected from the Kennicutt-Schmidt law.
description: 15 pages, 10 figures, accepted for publication in A&A
Large time behavior of solutions to a nonlinear hyperbolic relaxation system with slowly decaying data
Creators: name: Fukuda, Ikki
Publisher: name: arXiv
Year: 2019
Subjects: subject: Analysis of PDEs (math.AP)
subject: FOS: Mathematics
subject: 35B40, 35L70, 35L15

description: We consider the large time asymptotic behavior of the global solutions to the initial value problem for the nonlinear damped wave equation with slowly decaying initial data. When the initial data decay fast enough, it is known that the solution to this problem converges to the self-similar solution to the Burgers equation called a nonlinear diffusion wave and its optimal asymptotic rate is obtained. In this paper, we focus on the case that the initial data decay more slowly than previous works and derive the corresponding asymptotic profiles. Moreover, we investigate how the change of the decay rate of the initial values affect its asymptotic rate.
description: 32 pages
A multi-scale FEM-BEM formulation for contact mechanics between rough surfaces
Creators: name: Bonari, Jacopo
name: Marulli, Maria R.
name: Hagmeyer, Nora
name: Mayr, Matthias
name: Popp, Alexander
name: Paggi, Marco
Publisher: name: arXiv
Year: 2019
Subjects: subject: Computational Engineering, Finance, and Science (cs.CE)
subject: FOS: Computer and information sciences

description: A novel multi-scale finite element formulation for contact mechanics between nominally smooth but microscopically rough surfaces is herein proposed. The approach integrates the interface finite element method (FEM) for modelling interface interactions at the macro-scale with a boundary element method (BEM) for the solution of the contact problem at the micro-scale. The BEM is used at each integration point to determine the normal contact traction and the normal contact stiffness, allowing to take into account any desirable kind of rough topology, either real, e.g. obtained from profilometric data, or artificial, evaluated with the most suitable numerical or analytical approach. Different numerical strategies to accelerate coupling between FEM and BEM are discussed in relation to a selected benchmark test.
description: This is a pre-print of an article published in Computational Mechanics (2019). The final authenticated version is available online at: https://link.springer.com/article/10.1007/s00466-019-01791-3
The Evolving Interstellar Medium of Star-Forming Galaxies, as traced by $\texttt{Stardust}$
Creators: name: Kokorev, Vasily
name: Magdis, Georgios
name: Davidzon, Iary
name: Brammer, Gabriel
name: Valentino, Francesco
name: Daddi, Emanuele
name: Ciesla, Laure
name: Liu, Daizhong
name: Jin, Shuowen
name: Cortzen, Isabella
name: Delvecchio, Ivan
name: Giménez-Arteaga, Clara
name: Gómez-Guijarro, Carlos
name: Sargent, Mark
name: Toft, Sune
name: Weaver, John R.
Publisher: name: arXiv
Year: 2021
Subjects: subject: Astrophysics of Galaxies (astro-ph.GA)
subject: FOS: Physical sciences

description: We analyse the far-infrared properties of $\sim$ 5,000 star-forming galaxies at $z<4.5$, drawn from the deepest, super-deblended catalogues in the GOODS-N and COSMOS fields. We develop a novel panchromatic SED fitting algorithm, $\texttt{Stardust}$, that models the emission from stars, AGN, and infrared dust emission, without relying on energy balance assumptions. Our code provides robust estimates of the UV-optical and FIR physical parameters, such as the stellar mass ($M_*$), dust mass ($M_{\rm dust}$), infrared luminosities ($L_{\rm IR}$) arising from AGN and star formation activity, and the average intensity of the interstellar radiation field ($\langle U \rangle$). Through a set of simulations we quantify the completeness of our data in terms of $M_{\rm dust}$, $L_{\rm IR}$ and $\langle U \rangle$, and subsequently characterise the distribution and evolution of these parameters with redshift. We focus on the dust-to-stellar mass ratio ($f_{\rm dust}$), which we parametrise as a function of cosmic age, stellar mass, and specific star formation rate. The $f_{\rm dust}$ is found to increase by a factor of 10 from $z=0$ to $z=2$ and appears to remain flat at higher$-z$, mirroring the evolution of the gas fraction. We also find a growing fraction of warm to cold dust with increasing distance from the main sequence, indicative of more intense interstellar radiation fields, higher star formation efficiencies and more compact star forming regions for starburst galaxies. Finally, we construct the dust mass functions (DMF) of star-forming galaxies up to $z=1$ by transforming the stellar mass function to DMF through the scaling relations derived here. The evolution of $f_{\rm dust}$ and the recovered DMFs are in good agreement with the theoretical predictions of the Horizon-AGN and IllustrisTNG simulations.
description: 39 pages, 21 figures, 3 tables. Accepted to ApJ July 10, 2021
Deep Hubble Space Telescope Observations of GW170817: Complete Light Curves and the Properties of the Galaxy Merger of NGC 4993
Creators: name: Kilpatrick, Charles D.
name: Fong, Wen-fai
name: Blanchard, Peter K.
name: Leja, Joel
name: Nugent, Anya E.
name: Palmese, Antonella
name: Paterson, Kerry
name: Starkenburg, Tjitske
name: Alexander, Kate D.
name: Berger, Edo
name: Chornock, Ryan
name: Hajela, Aprajita
name: Margutti, Raffaella
Publisher: name: arXiv
Year: 2021
Subjects: subject: High Energy Astrophysical Phenomena (astro-ph.HE)
subject: Astrophysics of Galaxies (astro-ph.GA)
subject: FOS: Physical sciences

description: We present the complete set of {\it Hubble Space Telescope} imaging of the binary neutron star merger GW170817 and its optical counterpart AT 2017gfo. Including deep template imaging in F814W, F110W, F140W, and F160W at 3.4 years post-merger, we re-analyze the full light curve of AT 2017gfo across 12 bands from 5--1273 rest-frame days after merger. We obtain four new detections of the short $γ$-ray burst (GRB) 170817A afterglow from 109--170 rest-frame days post-merger. These detections are consistent with the previously observed $β=-0.6$ spectral index in the afterglow light curve with no evidence for spectral evolution. We also analyze our limits in the case of novel late-time optical and IR emission signatures, such as a kilonova afterglow or infrared dust echo, but find our limits are not constraining in these contexts. We use the new data to construct deep optical and infrared stacks, reaching limits of $M=-6.3$ to $-4.6$ mag, to analyze the local environment around AT 2017gfo and low surface brightness features in its host galaxy NGC 4993. We rule out the presence of any globular cluster at the position of AT 2017gfo to $2.3 \times 10^{4} L_{\odot}$, including those with the reddest $V-H$ colors. Finally, we analyze the substructure of NGC 4993 in deep residual imaging, and find shell features which extend up to 71.8\arcsec\ (14.2 kpc) from the center of the galaxy. We find that the shells have a cumulative stellar mass of $6.3\times10^{8} M_{\odot}$, roughly 2% the total stellar mass of NGC 4993, and mass-weighted ages of $>$3 Gyr. We conclude that it was unlikely the GW170817 progenitor system formed in the galaxy merger, which based on dynamical signatures and the stellar population in the shells mostly likely occurred 220--685 Myr ago.
description: 21 pages, 9 figures, submitted to ApJ
Exponential Resolution Lower Bounds for Weak Pigeonhole Principle and Perfect Matching Formulas over Sparse Graphs
Creators: name: de Rezende, Susanna F.
name: Nordström, Jakob
name: Risse, Kilian
name: Sokolov, Dmitry
Publisher: name: arXiv
Year: 2019
Subjects: subject: Computational Complexity (cs.CC)
subject: Logic in Computer Science (cs.LO)
subject: Combinatorics (math.CO)
subject: FOS: Computer and information sciences
subject: FOS: Mathematics
subject: F.2.2; F.1.3; I.2.3; F.4.1
subject: F.2.2, F.1.3, I.2.3, F.4.1

description: We show exponential lower bounds on resolution proof length for pigeonhole principle (PHP) formulas and perfect matching formulas over highly unbalanced, sparse expander graphs, thus answering the challenge to establish strong lower bounds in the regime between balanced constant-degree expanders as in [Ben-Sasson and Wigderson '01] and highly unbalanced, dense graphs as in [Raz '04] and [Razborov '03, '04]. We obtain our results by revisiting Razborov's pseudo-width method for PHP formulas over dense graphs and extending it to sparse graphs. This further demonstrates the power of the pseudo-width method, and we believe it could potentially be useful for attacking also other longstanding open problems for resolution and other proof systems.
description: 46 pages. This is the TheoretiCS journal version
Vanishing of Nil-terms and negative K-theory for additive categories
Creators: name: Bartels, Arthur
name: Lueck, Wolfgang
Publisher: name: arXiv
Year: 2020
Subjects: subject: K-Theory and Homology (math.KT)
subject: FOS: Mathematics
subject: 18E05, 19D35

description: We extend the notion of regular coherence from rings to additive categories and show that well-known consequences of regular coherence for rings also apply to additive categories. For instance the negative K-groups and all twisted Nil-groups vanish for an additive category if it is regular coherent. This will be applied to nested sequences of additive categories, motivated by our ongoing project to determine the algebraic K-theory of the Hecke algebra of a reductive p-adic group.
description: 64 pages, minor revisions in Section 14
Higher-order asymptotic profiles of the solutions to the viscous Fornberg-Whitham equation
Creators: name: Fukuda, Ikki
name: Itasaka, Kenta
Publisher: name: arXiv
Year: 2020
Subjects: subject: Analysis of PDEs (math.AP)
subject: FOS: Mathematics
subject: 35B40, 35Q53

description: We consider the initial value problem for the viscous Fornberg-Whitham equation which is one of the nonlinear and nonlocal dispersive-dissipative equations. In this paper, we establish the global existence of the solutions and study its asymptotic behavior. We show that the solution to this problem converges to the self-similar solution to the Burgers equation called the nonlinear diffusion wave, due to the dissipation effect by the viscosity term. Moreover, we analyze the optimal asymptotic rate to the nonlinear diffusion wave and the detailed structure of the solution by constructing higher-order asymptotic profiles. Also, we investigate how the nonlocal dispersion term affects the asymptotic behavior of the solutions and compare the results with the ones of the KdV-Burgers equation.
description: 29 pages
Fixed Point Sets and the Fundamental Group II: Euler Characteristics
Creators: name: Cappell, Sylvain
name: Weinberger, Shmuel
name: Yan, Min
Publisher: name: arXiv
Year: 2020
Subjects: subject: Algebraic Topology (math.AT)
subject: FOS: Mathematics
subject: 57Q91

description: For a group $G$ of not prime power order, Oliver showed that the obstruction for a finite CW-complex $F$ to be the fixed point set of a contractible finite $G$-CW-complex is the Euler characteristic $χ(F)$. He also has the similar results for compact Lie group actions. We show that the analogous problem for $F$ to be the fixed point set of a finite $G$-CW-complex of some given homotopy type is still determined by the Euler characteristic. Using trace maps in $K_0$, we also see that there are interesting roles for the fundamental group and the component structure of the fixed point set.
description: 25 pages, 2 figures
Continuous Conditional Random Field Convolution for Point Cloud Segmentation
Creators: name: Yang, Fei
name: Davoine, Franck
name: Wang, Huan
name: Jin, Zhong
Publisher: name: arXiv
Year: 2021
Subjects: subject: Computer Vision and Pattern Recognition (cs.CV)
subject: Robotics (cs.RO)
subject: FOS: Computer and information sciences

description: Point cloud segmentation is the foundation of 3D environmental perception for modern intelligent systems. To solve this problem and image segmentation, conditional random fields (CRFs) are usually formulated as discrete models in label space to encourage label consistency, which is actually a kind of postprocessing. In this paper, we reconsider the CRF in feature space for point cloud segmentation because it can capture the structure of features well to improve the representation ability of features rather than simply smoothing. Therefore, we first model the point cloud features with a continuous quadratic energy model and formulate its solution process as a message-passing graph convolution, by which it can be easily integrated into a deep network. We theoretically demonstrate that the message passing in the graph convolution is equivalent to the mean-field approximation of a continuous CRF model. Furthermore, we build an encoder-decoder network based on the proposed continuous CRF graph convolution (CRFConv), in which the CRFConv embedded in the decoding layers can restore the details of high-level features that were lost in the encoding stage to enhance the location ability of the network, thereby benefiting segmentation. Analogous to the CRFConv, we show that the classical discrete CRF can also work collaboratively with the proposed network via another graph convolution to further improve the segmentation results. Experiments on various point cloud benchmarks demonstrate the effectiveness and robustness of the proposed method. Compared with the state-of-the-art methods, the proposed method can also achieve competitive segmentation performance.
description: 20 pages + 8 pages (supplemental material)
Chiral Symmetry Breaking and Confinement from an Interacting Ensemble of Instanton-dyons in Two-flavor Massless QCD
Creators: name: DeMartini, Dallas
name: Shuryak, Edward
Publisher: name: arXiv
Year: 2021
Subjects: subject: High Energy Physics - Phenomenology (hep-ph)
subject: Nuclear Theory (nucl-th)
subject: FOS: Physical sciences

description: In this work we present the results from numerical simulations of an interacting ensemble of instanton-dyons in the $SU(3)$ gauge group with $N_f=2$ flavors of massless quarks. Dynamical quarks are included via the effective interactions induced by the fermionic determinant evaluated in the subspace of topological zero modes. The eigenvalue spectrum of the Dirac operator is studied at different volumes to extract the chiral condensate and eigenvalue gap, with both observables providing consistent values of the chiral transition temperature $T_c$. We find that a sufficient density of dyons is responsible for generating the confining potential and breaking the chiral symmetry, both of which are compatible with second-order transitions.
description: 13 pages, 10 figures
Visual perceptual, perceptual motor and temporal sequence tasks : the performance of average and below average readers
Creators: name: Watson, Rita P. M.
Publisher: name: University of British Columbia
Year: 2010

description: Although visual perceptual and perceptual motor tasks emerge from diverse theoretical rationales-and are used in a variety of contexts, systematic comparisons of the significance of task parameters in differentiating between subject groups are lacking. The present study compares the performance by average and below average readers on a group of visual perceptual, perceptual motor and temporal sequence tasks, systematically varied across presentation and response parameters, in order to explore the relative significance of task parameters, and also to examine cognitive processes used by the groups in task performance. Subjects were initially identified as average or below average readers on the basis of reading test scores, and the final sample of 40 average and 40 below average readers was selected by matching for IQ across reading groups. A battery of 10 tasks was administered to all subjects in the final sample. T-tests between groups indicated that some categories of tasks, including visual synthesis and temporal sequence tasks, differentiated between groups more powerfully than others, although no single parameter emerged as uniquely significant. Task inter-correlations and factor analysis results suggested that patterns of cognitive processes differed between groups. Average readers tended to use a single process in performance of several task variations, while the performance of below average readers tended to be dominated by task-specific demands.
Sulfur abundances in the Galactic bulge and disk
Creators: name: Lucertini, F.
name: Monaco, L.
name: Caffau, E.
name: Bonifacio, P.
name: Mucciarelli, A.
Publisher: name: arXiv
Year: 2021
Subjects: subject: Astrophysics of Galaxies (astro-ph.GA)
subject: Solar and Stellar Astrophysics (astro-ph.SR)
subject: FOS: Physical sciences

description: Context. The measurement of $α$-elements abundances provides a powerful tool to put constraints on chemical evolution and star formation history of galaxies. The majority of studies on the $α$-element Sulfur (S) are focused on local stars, making S behavior in other environments an astronomical topic yet to be analyzed. Aims. The investigation of S in the Galactic bulge has only recently been considered for the first time. This work aims to improve our knowledge on S behavior in this component of the Milky Way. Methods. We present S abundances of 74 dwarf and sub-giant stars in the Galactic bulge, 21 and 30 F and G thick and thin disk stars. We performed local thermodynamic equilibrium analysis and applied corrections for non-LTE on high resolution and high signal-to-noise UVES spectra. S abundances were derived from multiplets 1, 6 and 8 in the metallicity range $-2
description: 14 pages, 9 figures, 4 tables
Inferring Species Trees Directly from Biallelic Genetic Markers: Bypassing Gene Trees in a Full Coalescent Analysis
Creators: name: Bryant, David
name: Bouckaert, Remco
name: Felsenstein, Joseph
name: Rosenberg, Noah
name: RoyChoudhury, Arindam
Publisher: name: arXiv
Year: 2009
Subjects: subject: Populations and Evolution (q-bio.PE)
subject: FOS: Biological sciences

description: The multi-species coalescent provides an elegant theoretical framework for estimating species trees and species demographics from genetic markers. Practical applications of the multi-species coalescent model are, however, limited by the need to integrate or sample over all gene trees possible for each genetic marker. Here we describe a polynomial-time algorithm that computes the likelihood of a species tree directly from the markers under a finite-sites model of mutation, effectively integrating over all possible gene trees. The method applies to independent (unlinked) biallelic markers such as well-spaced single nucleotide polymorphisms (SNPs), and we have implemented it in SNAPP, a Markov chain Monte-Carlo sampler for inferring species trees, divergence dates, and population sizes. We report results from simulation experiments and from an analysis of 1997 amplified fragment length polymorphism (AFLP) loci in 69 individuals sampled from six species of {\em Ourisia} (New Zealand native foxglove).
From Glasma to Quark Gluon Plasma in heavy ion collisions
Creators: name: Venugopalan, Raju
Publisher: name: arXiv
Year: 2008
Subjects: subject: High Energy Physics - Phenomenology (hep-ph)
subject: Nuclear Experiment (nucl-ex)
subject: Nuclear Theory (nucl-th)
subject: FOS: Physical sciences

description: When two sheets of Color Glass Condensate collide in a high energy heavy ion collision, they form matter with very high energy densities called the Glasma. We describe how this matter is formed, its remarkable properties and its relevance for understanding thermalization of the Quark Gluon Plasma in heavy ion collisions. Long range rapidity correlations contained in the near side ridge measured in heavy ion collisions may allow one to directly infer the properties of the Glasma.
description: Plenary Topical Overview Talk, Quark Matter 2008; 10 pages 8 figures