5632 research outputs found
Sort by
The ALPINE–ALMA [C II] Survey: The Infrared–Radio Correlation and Active Galactic Nucleus Fraction of Star-forming Galaxies at z ∼ 4.4–5.9
No full textWe present the radio properties of 66 spectroscopically confirmed normal star-forming galaxies (SFGs) at 4.4 < z < 5.9 in the COSMOS field that were [C II]-detected in the Atacama Large Millimeter/submillimeter Array Large Program to INvestigate [C II] at Early times (ALPINE). We separate these galaxies (“C II-detected-all”) into lower-redshift (“C II-detected-lz”; 〈z〉 = 4.5) and higher-redshift (“C II-detected-hz”; 〈z〉 = 5.6) subsamples, and stack multiwavelength imaging for each subsample from X-ray to radio bands. A radio signal is detected in the stacked 3 GHz images of the C II-detected-all and lz samples at ≳3σ. We find that the infrared–radio correlation of our sample, quantified by q_TIR, is lower than the local relation for normal SFGs at a ∼3σ significance level, and is instead broadly consistent with that of bright submillimeter galaxies at 2 < z < 5. Neither of these samples show evidence of dominant active galactic nucleus activity in their stacked spectral energy distributions (SEDs), UV spectra, or stacked X-ray images. Although we cannot rule out the possible effects of the assumed spectral index and applied infrared SED templates in causing these differences, at least partially, the lower obscured fraction of star formation than at lower redshift can alleviate the tension between our stacked q_(TIR)s and those of local normal SFGs. It is possible that the dust buildup, which primarily governs the infrared emission, in addition to older stellar populations, has not had enough time to occur fully in these galaxies, whereas the radio emission can respond on a more rapid timescale. Therefore, we might expect a lower q_TIR to be a general property of high-redshift SFGs
Fusion systems with J-components over F-_(2^e) with e > 1
No full textLet κ be a finite simple group of Lie type over a field of even order q > 2. If κ is not ²F₄(q), then we determine the fusion systems ℱ of J-component type with a fully centralized involution j such that C_(ℱ)(j) has a component realized by κ. The exceptional case is treated in a later paper
Scalable Reinforcement Learning for Multiagent Networked Systems
No full textWe study reinforcement learning (RL) in a setting with a network of agents whose states and actions interact in a local manner where the objective is to find localized policies such that the (discounted) global reward is maximized. A fundamental challenge in this setting is that the state-action space size scales exponentially in the number of agents, rendering the problem intractable for large networks. In this paper, we propose a scalable actor critic (SAC) framework that exploits the network structure and finds a localized policy that is an O(ρκ+1)-approximation of a stationary point of the objective for some ρ∈(0,1), with complexity that scales with the local state-action space size of the largest κ-hop neighborhood of the network. We illustrate our model and approach using examples from wireless communication, epidemics, and traffic
The Neo‐Classical Challenge to Classical Theism
No full textThe classical theist tradition represented by thinkers like Anselm and Aquinas predicates several remarkable attributes of God, most notably simplicity or lack of parts of any kind. Neo-classical theists have recently developed several lines of criticism of these attributes. But these criticisms are not effective against the historically most influential way of spelling out classical theism, which is Thomism
Fuzzy neural network controller of interconnected method for civil structures
No full textRecently, an increasing number of cutting-edged studies have shown that designing a smart active control for real-time implementation requires piles of hard-work criteria in the design process, including performance controllers to reduce the tracking errors and tolerance to external interference and measure system disturbed perturbations. This article proposes an effective artificial-intelligence method using these rigorous criteria, which can be translated into general control plants for the management of civil engineering installations. To facilitate the calculation, an efficient solution process based on linear matrix (LMI) inequality has been introduced to verify the relevance of the proposed method, and extensive simulators have been carried out for the numerical constructive model in the seismic stimulation of the active rigidity. Additionally, a fuzzy model of the neural network based system (NN) is developed using an interconnected method for LDI (linear differential) representation determined for arbitrary dynamics. This expression is constructed with a nonlinear sector which converts the nonlinear model into a multiple linear deformation of the linear model and a new state sufficient to guarantee the asymptomatic stability of the Lyapunov function of the linear matrix inequality. In the control design, we incorporated H Infinity optimized development algorithm and performance analysis stability. Finally, there is a numerical practical example with simulations to show the results. The implication results in the RMS response with as well as without tuned mass damper (TMD) of the benchmark building under the external excitation, the El-Centro Earthquake, in which it also showed the simulation using evolved bat algorithmic LMI fuzzy controllers in term of RMS in acceleration and displacement of the building
WDJ220838.73+454434.04: a White Dwarf Companion in the AR Lacertae System
No full textWe present WDJ220838.73+454434.04 (hereafter WD2208+454), a wide, co-moving white dwarf companion to the eclipsing binary system, AR Lacertae. The companion was discovered through the Backyard Worlds: Planet 9 citizen science collaboration. It has a separation of 21.″9 on the sky from the central eclipsing pair, translating to a projected separation of ∼930 au. We present a review of the physical properties and orbital parameters of this new addition to the system
Geometry-kinematics duality
No full textWe propose a mapping between geometry and kinematics that implies the classical equivalence of any theory of massless bosons—including spin and exhibiting arbitrary derivative or potential interactions—to a nonlinear sigma model (NLSM) with a momentum-dependent metric in field space. From this kinematic metric we construct a corresponding kinematic connection, covariant derivative, and curvature, all of which transform appropriately under general field redefinitions, even including derivatives. We show explicitly how all tree-level on-shell scattering amplitudes of massless bosons are equal to those of the NLSM via the replacement of geometry with kinematics. Lastly, we describe how the recently introduced geometric soft theorem of the NLSM, which universally encodes all leading and subleading soft scalar theorems, also captures the soft photon theorems
Untangling the Galaxy. IV. Empirical Constraints on Angular Momentum Evolution and Gyrochronology for Young Stars in the Field
No full textWe present a catalog of ∼100,000 periodic variable stars in Transiting Exoplanet Survey Satellite (TESS) full-frame image data among members of widely distributed moving groups identified with Gaia in the previous papers in the series. By combining the periods from our catalog attributable to rotation with previously derived rotation periods for benchmark open clusters, we develop an empirical gyrochronology relation of angular momentum evolution that is valid for stars with ages 10–1000 Myr. Excluding stars rotating faster than 2 days, which we find are predominantly binaries, we achieve a typical age precision of ≈0.2–0.3 dex and improving at older ages. Importantly, these empirical relations apply to not only FGK-type stars but also M-type stars, due to the angular momentum distribution being much smoother, simpler, continuous, and monotonic as compared to the rotation period distribution. As a result, we are also able to begin tracing in fine detail the nature of angular momentum loss in low-mass stars as functions of mass and age. We characterize the stellar variability amplitudes of the cool stars as functions of mass and age, which may correlate with the starspot covering fractions. We also identify pulsating variables among the hotter stars in the catalog, including δ Scuti, γ Dor, and slowly pulsating B-type variables. These data represent an important step forward in being able to estimate precise ages of FGK- and M-type stars in the field, starting as early as the pre-main-sequence phase of evolution
Asteroid Measurements at Millimeter Wavelengths with the South Pole Telescope
No full textWe present the first measurements of asteroids in millimeter wavelength data from the South Pole Telescope (SPT), which is used primarily to study the cosmic microwave background (CMB). We analyze maps of two ∼270 deg² sky regions near the ecliptic plane, each observed with the SPTpol camera ∼100 times over 1 month. We subtract the mean of all maps of a given field, removing static sky signal, and then average the mean-subtracted maps at known asteroid locations. We detect three asteroids -- (324) Bamberga, (13) Egeria, and (22) Kalliope -- with signal-to-noise ratios (S/N) of 11.2, 10.4, and 6.1, respectively, at 2.0 mm (150 GHz); we also detect (324) Bamberga with an S/N of 4.1 at 3.2 mm (95 GHz). We place constraints on these asteroids' effective emissivities, brightness temperatures, and light-curve modulation amplitude. Our flux density measurements of (324) Bamberga and (13) Egeria roughly agree with predictions, while our measurements of (22) Kalliope suggest lower flux, corresponding to effective emissivities of 0.64 ± 0.11 at 2.0 and < 0.47 at 3.2 mm. We predict the asteroids detectable in other SPT data sets and find good agreement with detections of (772) Tanete and (1093) Freda in recent data from the SPT-3G camera, which has ∼10× the mapping speed of SPTpol. This work is the first focused analysis of asteroids in data from CMB surveys, and it demonstrates we can repurpose historic and future data sets for asteroid studies. Future SPT measurements can help constrain the distribution of surface properties over a larger asteroid population
Astrophysical Observations of a Dark Matter-Baryon Fifth Force
No full textWe consider the effects of an attractive, long-range Yukawa interaction
between baryons and dark matter (DM), focusing in particular on temperature and
pulsar timing observations of neutron stars (NSs). We show that such a fifth
force, with strength modestly stronger than gravity at ranges greater than tens
of kilometers (corresponding to mediator masses less than ), can dramatically enhance dark matter kinetic heating, capture, and
pulsar timing Doppler shifts relative to gravity plus short range interactions
alone. Using the coldest observed NS and pulsar timing array (PTA) data, we
derive limits on fifth force strength over a DM mass range spanning light dark
matter up to order solar mass composite DM objects. We also consider an
indirect limit by combining bullet cluster limits on the DM self-interaction
with weak equivalence principle test limits on baryonic self-interactions. We
find the combined indirect limits are moderately stronger than kinetic heating
and PTA limits, except when considering a DM subcomponent