By fitting the bolometric light curves of 31 super-luminous supernovae (SLSNe) with the magnetar engine model, we derive the ejecta masses and magnetar parameters for these SLSNe. The lower boundary of magnetic field strengths of SLSN magnetars can be set just around the critical field strength B c of electron Landau quantization. In more details, SLSN magnetars can further be divided into two subclasses of magnetic fields of ∼ (1 − 5)B c and ∼ (5 − 10)B c , respectively. It is revealed that these two subclasses of magnetars are just associated with the slow-evolving and fast-evolving bolometric light curves of SLSNe. In comparison, the magnetars harbored in gamma-ray bursts (GRBs) and associated hypernovae are usually inferred to have much higher magnetic fields with a lower boundary about ∼ 10B c . This robustly suggests that it is the magnetic fields that play the crucial role in distinguishing SLSNe from GRBs/hypernovae. The rotational energy of SLSN magnetars are found to be correlated with the masses of supernova ejecta, which provides a clue to explore the nature of their progenitors. Moreover, the distribution of ejecta masses of SLSNe is basically intermediate between those of normal core-collapse supernovae and hypernovae. This could indicate an intrinsic connection among these different stellar explosions.

We present results from the first directed search for nontensorial gravitational waves. While general relativity allows for tensorial (plus and cross) modes only, a generic metric theory may, in principle, predict waves with up to six different polarizations. This analysis is sensitive to continuous signals of scalar, vector, or tensor polarizations, and does not rely on any specific theory of gravity. After searching data from the first observation run of the advanced LIGO detectors for signals at twice the rotational frequency of 200 known pulsars, we find no evidence of gravitational waves of any polarization. We report the first upper limits for scalar and vector strains, finding values comparable in magnitude to previously published limits for tensor strain. Our results may be translated into constraints on specific alternative theories of gravity.

Deregulation eliminates the boundary of the territory of the monopoly power industry. Competition forces utilities to improve power quality as well as to reduce investment and operation costs. Feeder imbalance describes a situation in which the voltages of a three-phase voltage source are not identical in magnitude, or the phase differences between them are not 120 electrical degrees, or both. It affects motors and other devices that depend upon a wellbalanced three-phase voltage source. Phase balancing is to make the voltages balanced at each load point of the feeder. Phase swapping is a direct approach for phase balancing with the minimum cost. Phase balancing can enhance utilities' There are two approaches for phase balancing. One is feeder reconfiguration at the system level; the other is phase swapping at the feeder level. Feeder reconfiguration has been extensively studied in the past several decades while phase swapping has been ignored. Since feeder reconfiguration is primarily designed for load balancing among the feeders, most researchers do not consider phase balancing as an objective in feeder reconfiguration. Only a few people incorporated phase balancing into feeder reconfiguration approaches based on the unbalanced feeder systems[3-6]. But they realized that feeder reconfiguration has limitation to reach phase balancing [3-6]. competitive capability by improving reliability, quality, and reducing costs. Therefore, phase balancing optimization is nowadays receiving more attention in the power industry, especially in today's deregulating environments. The nonlinear effects, such as, voltage drops and energy losses, make the problem difficult to solve. This paper introduces Simulated Annealing as an effective method to solve a power distribution phase balancing problem with its non-linear rffert. _.._I.".

Neutron star mergers are believed to occur in accretion disks around supermassive black holes. Here we show that a putative jet launched from the merger of a binary neutron star (BNS) or a neutron star–black hole (NSBH) merger occurring at the migration trap in an active galactic nucleus (AGN) disk would be choked. The jet energy is deposited within the disk materials to power a hot cocoon. The cocoon is energetic enough to break out from the AGN disk and produce a bright X-ray shock breakout transient peaking at ∼0.15 days after the merger. The peak luminosity is estimated as , which can be discovered by the Einstein Probe from . Later on, the nonrelativistic ejecta launched from the merger would break out the disk, powering an X-ray/UV flare peaking at ∼0.5 days after the merger. This second shock breakout signal may be detected by UV transient searches. The cocoon cooling emission and kilonova emission are outshone by the disk emission and are difficult to detect. Future joint observations of gravitational waves from BNS/NSBH mergers and associated two shock breakout signatures can provide strong support for the compact binary coalescence formation channel in AGN disks.

When the magnetosphere of a magnetar is perturbed by crustal deformation, an electric field E ∥ parallel to the magnetic field line would appear via Alfvén waves in the charge starvation region. The electron–positron pair bunches will be generated via two-stream instability in the magnetosphere, and these pairs will undergo charge separation in the E ∥ and in the meantime emit coherent curvature radiation. Following the approach of Yang & Zhang, we find that the superposed curvature radiation becomes narrower due to charge separation, with the width of spectrum depending on the separation between the electron and positron clumps. This mechanism can interpret the narrow spectra of fast radio bursts (FRBs), in particular, the spectrum of Galactic FRB 200428 recently detected in association with a hard X-ray burst from the Galactic magnetar SGR J1935+2154.

We analyse the tidal disruption probability of potential neutron star-black hole (NSBH) merger gravitational wave (GW) events, including GW190426 152155, GW190814, GW200105 162426 and GW200115 042309, detected during the third observing run of the LIGO/Virgo Collaboration, and the detectability of kilonova emission in connection with these events. The posterior distributions of GW190814 and GW200105 162426 show that they must be plunging events and hence no kilonova signal is expected from these events. With the stiffest NS equation of state allowed by the constraint of GW170817 taken into account, the probability that GW190426 152155 and GW200115 042309 can make tidal disruption is ∼ 24% and ∼ 3%, respectively. However, the predicted kilonova brightness is too faint to be detected for present follow-up search campaigns, which explains the lack of electromagnetic (EM) counterpart detection after triggers of these GW events. Based on the best constrained population synthesis simulation results, we find that disrupted events account for only 20% of cosmological NSBH mergers since most of the primary BHs could have low spins. The associated kilonovae for those disrupted events are still difficult to be discovered by LSST after GW triggers in the future, because of their low brightness and larger distances. For future GW-triggered multi-messenger observations, potential short-duration gamma-ray bursts and afterglows are more probable EM counterparts of NSBH GW events.

We fit the multiband lightcurves of 40 fast blue optical transients (FBOTs) with the magnetar engine model. The mass of the FBOT ejecta, the initial spin period, and the polar magnetic field of the FBOT magnetars are respectively constrained to M ej = 0.11 − 0.09 + 0.22 M ⊙ , P i = 9.1 − 4.4 + 9.3 ms , and B p = 11 − 7 + 18 × 10 14 G . The wide distribution of the value of B p spreads the parameter ranges of the magnetars from superluminous supernovae (SLSNe) to broad-line Type Ic supernovae (SNe Ic-BL; some are observed to be associated with long-duration gamma-ray bursts), which are also suggested to be driven by magnetars. Combining FBOTs with the other transients, we find a strong universal anticorrelation of P i ∝ M ej − 0.41 , indicating they could share a common origin. To be specific, it is suspected that all of these transients originate from the collapse of extremely stripped stars in close binary systems, but with different progenitor masses. As a result, FBOTs distinguish themselves by their small ejecta masses with an upper limit of ∼1 M ⊙, which leads to an observational separation in the rise time of the lightcurves of ∼10 days. In addition, FBOTs together with SLSNe can be separated from SNe Ic-BL by an empirical line in the M peak–t rise plane corresponding to an energy requirement of the mass of 56Ni of ∼0.3M ej, where M peak is the peak absolute magnitude of the transients and t rise is the rise time.

After the successful detection of a gravitational-wave (GW) signal and its associated electromagnetic (EM) counterparts from GW170817, neutron star–black hole (NSBH) mergers have been highly expected to be the next type of multimessenger source. However, despite the detection of several NSBH merger candidates during the GW third observation run, no confirmed EM counterparts from these sources have been identified. The most plausible explanation is that these NSBH merger candidates were plunging events mainly because the primary black holes (BHs) had near-zero projected aligned spins based on GW observations. In view of the fact that neutron stars (NSs) can be easily tidally disrupted by BHs with high projected aligned spins, we study an evolution channel to form NSBH binaries with fast-spinning BHs, the properties of BH mass and spin, and their associated tidal disruption probability. We find that if the NSs are born first, the companion helium stars would be tidally spun up efficiently, and would thus finally form fast-spinning BHs. If BHs do not receive significant natal kicks at birth, these NSBH binaries that can merge within Hubble time would have BHs with projected aligned spins χ z ≳ 0.8 and, hence, can certainly allow tidal disruption to happen. Even if significant BH kicks are considered for a small fraction of NSBH binaries, the projected aligned spins of BHs are χ z ≳ 0.2. These systems can still be disrupted events unless the NSs are very massive. Thus, NS-first-born NSBH mergers would be promising multimessenger sources. We discuss various potential EM counterparts associated with these systems and their detectability in the upcoming fourth observation run.