Search

We present our optical photometric observations of the 2022 eruption of the recurrent nova U Scorpii (U Sco) using 49,152 data points over 70 d following the optical peak. We have also analyzed its soft X-ray (0.3--1 keV) light curve by the Neil Gehrels Swift Observatory. During the 2022 eruption, the optical plateau stage started 13.8--15.0 d and ended 23.8--25.0 d after the optical peak. The soft X-ray stage started 14.6--15.3 d and ended 38.7--39.5 d after the optical peak. Both stages started later and had shorter durations, and the soft X-ray light curve peaked earlier and was less luminous compared to those during the U Sco 2010 eruption. These points suggest that there were differences in the envelope mass between the different cycles of the nova eruption. Furthermore, we have analyzed the optical eclipses during the 2022 eruption. The primary eclipse was first observed 10.4--11.6 d after the optical peak, earlier than the beginning of the optical plateau stage. This sequence of events can be explained by the receding ejecta photosphere associated with the expanding nova ejecta. We have determined the ingress and egress phases of the primary eclipses and estimated the outer radius of the optical light source centered at the white dwarf (WD). During the optical plateau stage, the source radius remained $\sim$1.2 times larger than the Roche volume radius of the primary WD, being close to the L1 point. When the optical plateau stage ended, the source radius drastically shrank to the tidal truncation radius within a few orbital periods. This previously unresolved phenomenon can be interpreted as a structural change in U Sco where the temporarily expanded accretion disk due to the nova wind returned to a steady state., Comment: 16 pages, 7 figures, 7 tables, accepted for publication in PASJ; doi:10.1093/pasj/psae010

Lightcurves of many classical novae deviate from the canonical "fast rise - smooth decline" pattern and display complex variability behavior. We present the first TESS-space-photometry-based investigation of this phenomenon. We use TESS Sector 41 full-frame images to extract a lightcurve of the slow Galactic nova V606 Vul that erupted nine days prior to the start of the TESS observations. The lightcurve covers the first of two major peaks of V606 Vul that was reached 19 days after the start of the eruption. The nova reached its brightest visual magnitude V=9.9 in its second peak 64 days after the eruption onset, following the completion of Sector 41 observations. To increase the confidence level of the extracted lightcurve, we performed the analysis using four different codes implementing the aperture photometry (Lightkurve, VaST) and image subtraction (TESSreduce, tequila_shots) and find good agreement between them. We performed ground-based photometric and spectroscopic monitoring to complement the TESS data. The TESS lightcurve reveals two features: periodic variations (0.12771d, 0.01mag average peak-to-peak amplitude) that disappeared when the source was within 1mag of peak optical brightness and a series of isolated mini-flares (with peak-to-peak amplitudes of up to 0.5mag) appearing at seemingly random times. We interpret the periodic variations as the result of azimuthal asymmetry of the photosphere engulfing the nova-hosting binary that was distorted by and rotating with the binary. Whereas we use spectra to associate the two major peaks in the nova lightcurve with distinct episodes of mass ejection, the origin of mini-flares remains elusive., Comment: 31 pages, 10 figures, submitted to ApJ; comments welcome

We propose a low-cost reconfigurable metasurface transmitter to implement generalized polarization-space modulation (GPSM) that has been proposed for next-generation wireless communications. Unlike conventional multiple-input multiple-output GPSM, our electromagnetically-compliant, reduced form-factor design using Barium-Strontium-Titanate film yields more than two polarization states. Full-wave simulations show our optimized design achieves 0.08-0.95 polarization conversion ratio with 5% bandwidth at 28 GHz and bit error rates comparable or better than conventional systems., Comment: 10 pages, 5 figures, 1 table

Reconfigurable intelligent surfaces (RIS) have recently received significant attention as building blocks for smart radio environments and adaptable wireless channels. By altering the space- and time-varying electromagnetic (EM) properties, the RIS transforms the inherently stochastic nature of the wireless environment into a programmable propagation channel. Conventionally, designing RIS to yield the desired EM response requires trial-and-error by iteratively investigating a large possibility of various geometries and materials through thousands of full-wave EM simulations. In this context, deep learning (DL) techniques are proving critical in reducing the computational cost and time of RIS inverse design. Instead of explicitly solving Maxwell's equations, DL models learn physics-based relationships through supervised training data. Further, generative adversarial networks are shown to synthesize novel RIS designs not previously seen in the literature. This article provides a synopsis of DL techniques for inverse RIS design and optimization to yield targeted EM response necessary for future wireless networks., Comment: 7 pages, 5 figures, 1 table

Index modulation (IM) is one of the candidate technologies for the upcoming sixth generation (6G) wireless communications networks. In this paper, we propose a space-time-modulated reconfigurable intelligent metasurface (RI-MTS) that is configured to implement various frequency-domain IM techniques in a multiple-input multiple-output (MIMO) array configuration. Unlike prior works which mostly analyze signal theory of general RI-MTS IM, we present novel electromagnetics-compliant designs of specific IMs such as sub-carrier index modulation (SIM) and MIMO orthogonal frequency-domain modulation IM (MIMO-OFDM-IM). Our full-wave electromagnetic simulations and analytical computations establish the programmable ability of these transceivers to vary the reflection phase and generate frequency harmonics for IM. Our experiments for bit error rate show that RI-MTS-based SIM and MIMO-OFDM-IM are lower than conventional MIMO-OFDM., Comment: 5 pages, 4 figures

The development of skill standards for Health Science was a result of a collaborative effort involving the Nevada Department of Education and a writing team with extensive experience in both teaching and in the field. The skill standards presented in this report features a framework for students interested in pursuing careers in healthcare and support the STEM initiative in Nevada. Each program should provide students with the opportunity to explore a variety of careers and leadership opportunities through career and technical student organizations like Health Occupation Students of America (HOSA). The variety of content standards allows a program to customize the needs of their students, the community and their district to meet the needs of the heath care industry. The content and performance standards are driven by the National Health Care Foundation Standards and the Career Clusters Pathways for Health Science/Law and Public Safety. A student considered successful in the completion of all the performance indicators in Level 1 and 2 should be able to obtain a passing score on the National Health Science Assessment. The final section of this document shows the correlation of the standards to several academic standard areas. These standards do meet and exceed the requirements of the Nevada Life Science and Health Standards. Where correlation with an academic standard exists, students in a health science program perform learning activities that support, either directly or indirectly, achievement of one or more academic standards.

Turyshev, S.G., Toth, V.T., 2009. (preprint arXiv:0906.0399) reported on the status of the analysis of recently recovered Pioneer 10 (P10) and Pioneer 11 (P11) flight data and commented on some, but not all, of the characteristics of the Pioneer Anomaly (PA) that must be explained by a candidate model. Only one model presented to date is consistent with all the characteristics., Comment: 1 page

The unexplained sunward acceleration $a_\mathrm{P}$ of the Pioneer 10 (P10) and the Pioneer 11 (P11) spacecraft remains a mystery. A scalar potential model (SPM) that derived from considerations of galaxy clusters, of redshift, and of H{\scriptsize{I}} rotation curves of spiral galaxies is applied to the Pioneer Anomaly. Matter is posited to warp the scalar potential $\rho$ field. The changing $\rho$ field along the light path causes the Pioneer Anomaly. The SPM is consistent with the general value of $a_\mathrm{P}$; with the annual periodicity; with the differing $a_\mathrm{P}$ between the spacecraft; with the discrepancy between {\textit{Sigma}} and CHASMP programs at P10 (I) and their closer agreement at P10 (III); with the slowly declining $a_\mathrm{P}$; with the low value of $a_\mathrm{P}$ immediately before the P11's Saturn encounter; with the high uncertainty in the value of $a_\mathrm{P}$ obtained during and after the P11's Saturn encounter; and with the cosmological connection suggested by $a_\mathrm{P} \approx cH_\mathrm{o}$. The effect of the $\rho$ field warp appears as the curvature of space proposed by general relativity (GR). The Hubble Law and $a_\mathrm{P} \approx cH_\mathrm{o}$ are manifestations of the Newtonian spherical property. Therefore, gravitational attraction, the equivalence principle, and the planet ephemeris remain as described by GR. GR corresponds to the SPM in the limit in which the Sources and Sinks may be replaced by a flat and static $\rho$ field such as between cluster cells and on the Solar System scale at a relatively large distance from a Source or Sink., Comment: includes suggested clarifications

The galaxy central mass $M_\mathrm{c}$ and central velocity dispersion $\sigma_\mathrm{c}$ have been found to correlate with large scale galaxy parameters for samples of galaxies with a limited range of characteristics. A scalar potential model (SPM) that derived from considerations of galaxy clusters, of redshift, of discrete redshift, of H{\scriptsize{I}} rotation curves (RCs) of spiral galaxies and of RC asymmetry is applied to central region parameters. The $\sigma_\mathrm{c}$ and $ M_\mathrm{c}$ are found to correlate to the host galaxy's and neighboring galaxy's B band luminosity. The sample included galaxies with rising, flat and declining RCs; galaxies with a wide range of characteristics; and galaxies excluded from samples of other studies of $\sigma_\mathrm{c}$ relationships. The equations have the same form as the SPM equations for the parameters of the H{\scriptsize{I}} RCs. Because the SPM is consistent with $M_\mathrm{c}$ and $\sigma_\mathrm{c}$ observations of the sample galaxies, the Sources and Sinks act as monopoles at the center of the galaxies around them. This suggests the outward scalar potential force of a Source holds the $M_\mathrm{c}$ from collapse into a supermassive black hole.

A scalar potential model (SPM) was developed from considerations of galaxy clusters and of redshift. The SPM is applied to HI rotation curves (RCs) and RC asymmetry of spiral galaxies. The resulting model adds the force of a scalar potential of the host galaxy and of neighboring galaxies to the Newtonian rotation velocity equation. The RC is partitioned radially into regions. The form of the equation for each parameter of each region is the same with differing proportionality constants. Integer values of each equation are determined empirically for each galaxy. Among the sample galaxies, the global properties of galaxies of B band luminosity, of position, and of orientation determine the RC and RC asymmetry. The Source of the scalar field acts as a monopole at distances of a few kpc from the centre of spiral galaxies. The scalar potential field causes Newtonian mechanics to considerably underestimate the mass in galaxies, which is the ``missing mass problem''. The SPM is consistent with RC and RC asymmetry observations of the sample spiral galaxies., Comment: submitted to MNRAS

A derivation of a theoretical, time average, cosmic microwave background (CMB), Planckian temperature V of the universe remains a challenge. A scalar potential model (SPM) that resulted from considerations of galaxy cells is applied to deriving a value for V. The heat equation is solved for a cell with the boundary conditions of SPM Source and Sink characteristics, with simplified cell characteristics, and with zero initial temperature. The universe is a collection of cells. The CMB radiation is black body radiation with the cells acting as radiators and absorbers. Conventional thermodynamics is applied to calculate V = 2.718 K. The temperature and matter content of cells are finely controlled by a feedback mechanism. Because time is required for matter to flow from Sources to Sinks, the radiation temperature of cells cycles about V after an initial growth phase. If the universe is like an ideal gas in free expansion and is not in thermal equilibrium, then the pressure and volume follow the measured CMB temperature vm = 2.725 K. Therefore, increasing vm >V equates to an expansion pressure on matter and expanding volume., Comment: 4 pages, submitted to Phys. Rev. D-15

On the galactic scale the universe is inhomogeneous and redshift $z$ is occasionally less than zero. A scalar potential model (SPM) that links the galaxy scale $z$ to the cosmological scale $z$ of the Hubble Law is postulated. Several differences among galaxy types suggest that spiral galaxies are Sources and that early type, lenticular, and irregular galaxies are Sinks of a scalar potential field. The morphology-radius and the intragalactic medium cluster observations support the movement of matter from Source galaxies to Sink galaxies. A cell structure of galaxy groups and clusters is proposed to resolve a paradox concerning the scalar potential like the Olber's paradox concerning light. For the sample galaxies, the ratio of the luminosity of Source galaxies to the luminosity of Sink galaxies approaches $2.7 \pm 0.1$. An equation is derived from sample data, which is anisotropic and inhomogeneous, relating $z$ of and the distance $D$ to galaxies. The calculated $z$ has a correlation coefficient of 0.88 with the measured $z$ for a sample of 32 spiral galaxies with $D$ calculated using Cepheid variable stars. The equation is consistent with $z<0$ observations of close galaxies. At low cosmological distances, the equation reduces to $z \approx \exp(KD) \, -1 \approx KD$, where $K$ is a constant, positive value. The equation predicts $z$ from galaxies over 18 Gpc distant approaches a constant value on the order of 500. The SPM of $z$ provides a physical basis for the $z$ of particle photons. Further, the SPM qualitatively suggests the discrete variations in $z$, which was reported by W. G. Tifft, 1997, Astrophy. J. 485, 465 and confirmed by others, are consistent with the SPM., Comment: 36 pages, 17 figures, Article in press New Astronomy

The changing universe model (CUM) describes galaxy parameter relationships (SESAPS '03, session EB 2). The CUM must be successfully applied to cosmological scale observations to be considered a cosmological model. A major component of current cosmological models is the Hubble constant $H_\mathrm{o}$. An equation is derived using the CUM model relating redshift $z$ and the distance $D$ to galaxies and is applied to a sample of 32 spiral galaxies with $D$ calculated using Cepheid variable stars. The equation predicts a galaxy may have $z<0$ in special circumstances. Three elliptical galaxies with peculiar characteristics are discovered to be CUM Sinks. The Sinks give a physical explanation of the ``Virgocentric infall'' and ``Great Attractor'' observations without a large, unobserved mass. At low cosmological distances, the equation reduces to $z \approx \exp(KD) -1 \approx KD$, where $K$ is a constant, positive value. The equation predicts $z$ from galaxies over 23 Gpc distant approaches a constant value on the order of 1000. The CUM gives a physical basis for the Doppler shift of particle photons., Comment: Presented at SESAPS '04, session GD.015, 11 pages

Although the current galaxy models yield calculations consistent with much of the data, many irregularities exist, exceptions have been found to the current models, the $\Lambda$CDM model apparently fails on galaxy scales, dark matter remains elusive, the phenomena at the center of galaxies are only beginning to be addressed, and many observations and empirical relationships are unexplained. A changing universe model (CUM) is proposed that posits the stuff of our universe is continually erupting into our universe from sources at the center of galaxies. In this first test of the CUM, a single equation that describes the rotation velocity curve of spiral galaxies is derived. The equation is also used to correlate the measured mass of the theorized, central supermassive black hole with other galaxy parameters. The equation adds one parameter for each mature galaxy and one parameter for each particle (atom nucleus and smaller) species to Newtonian dynamics. Rising, flat, and declining rotation velocity curves are explained without unknown dark matter. Ten previously unknown parametric relationships are discovered. Also, the CUM integrates several heretofore unrelated observations. The CUM model is in an early development stage and has already predicted new relationships among galaxy parameters.

The rotation velocity asymmetry v observed in spiral galaxy HI rotation curves linearly correlates with the effective potential force from the 10 closest neighboring galaxies normalized for the test particle mass and the gravitational constant. The magnitude of the potential force from a close galaxy is proportional to the luminosity of the close galaxy and inversely proportional to the square of the distance from the close galaxy to the target galaxy. The correlation coefficient is 0.99 and F test is 0.99. Also, the slope of the rotation curve in the disk region of a galaxy from rising to flat to declining is qualitatively correlated with increasing asymmetry and, hence, to the net force from other galaxies. The result is based on a sample of nine spiral galaxies with published Cepheid distances and rotation curves and with a wide range of characteristics. These relationships are interesting not only for their predictive power but also because (1) they suggest a galaxy's dynamics and the shape of its rotation curve are related to the potential energy and distance of neighboring galaxies, (2) they suggest a rising rotation curve in the disk region is intrinsic, (3) they suggest the Tully-Fisher relationship's assumption that the mass to intrinsic luminosity ratio is constant among galaxies is valid, and (4) they are inconsistent with MOND, dark matter, and the Linear Potential Model., Comment: 8 pages, 2 figure, AASTeX, Presented at the 202nd AAS Meeting, Session 40.08

A correlation between (1) the difference between the Tully-Fisher calculated distance and Cepheid calculated distance for a target galaxy and (2) the magnitude and distance of galaxies close to the target galaxy is described. The result is based on a sample of 31 galaxies that have published Cepheid distances with a wide range of characteristics and distances from 2.02 Mpc to 49.7 Mpc. The energy impinging on a target galaxy from neighboring galaxies is related to the residual between Tully-Fisher and Cepheid distance calculations of the target galaxy. These relations have four different zones dependent on the value of the impinging energy. The correlation coefficients are 0.77, 0.87, 0.81, and 0.98, respectively. This relationship is of interest not only for its ability to reduce the Tully-Fisher to Cepheid distance residual but also because it suggests neighboring galaxies have a strong influence on the apparent luminosity of galaxies and it suggests the Tully-Fisher relationship assumption that the intrinsic mass to intrinsic luminosity ratio is constant among galaxies is valid for z < 0.006., Comment: 14 pages, 4 figures, LaTex, correct typos, presented at American Astronomical Society 202nd meeting, session 40.08