Closure Relations for Electron-Positron Pair-Signatures in Gamma-Ray Bursts

We present recipes to diagnose the fireball of gamma-ray bursts (GRBs) by combining observations of electron-positron pair-signatures (the pair-annihilation line and the cutoff energy due to the pair-creation process). Our recipes are largely model-independent and extract information even from the non-detection of either pair-signature. We evaluate physical quantities such as the Lorentz factor, optical depth and pair-to-baryon ratio, only from the observable quantities. In particular, we can test whether the prompt emission of GRBs comes from the pair/baryonic photosphere or not. The future-coming Gamma-Ray Large Area Space Telescope (GLAST) satellite will provide us with good chances to use our recipes by detecting or non-detecting pair-signatures.Comment: 7 pages, 4 figures, accepted for publication in ApJ, with extended discussions. Conclusions unchange

Microlensing of collimated Gamma-Ray Burst afterglows

We investigate stellar microlensing of the collimated gamma-ray burst afterglows. A spherical afterglow appears on the sky as a superluminally expanding thin ring (``ring-like'' image), which is maximally amplified as it crosses the lens. We find that the image of the collimated afterglow becomes quite uniform (``disk-like'' image) after the jet break time (after the Lorentz factor of the jet drops below the inverse of the jet opening angle). Consequently, the amplification peak in the light curve after the break time is lower and broader. Therefore detailed monitoring of the amplification history will be able to test whether the afterglows are jets or not, i.e., ``disk-like'' or not, if the lensing occurs after the break time. We also show that some proper motion and polarization is expected, peaking around the maximum amplification. The simultaneous detection of the proper motion and the polarization will strengthen that the brightening of the light curve is due to microlensing.Comment: 16 pages, 6 figures, accepted for publication in Ap

Trans-Ejecta High-Energy Neutrino Emission from Binary Neutron Star Mergers

The observations of a macronova/kilonova accompanied by gravitational waves from a binary neutron star merger (GW170817) confirmed that neutron star coalescences produce copious ejecta. The coincident gamma-ray detection implies the existence of a relativistic jet in this system. During the jet's propagation within the ejecta, high-energy photons and neutrinos can be produced. The photons are absorbed by the ejecta, while the neutrinos escape and can be detected. Here, we estimate such trans-ejecta neutrino emission, and discuss how neutrino observations could be used to differentiate between gamma-ray burst emission scenarios. We find that neutrinos from the internal shocks inside the ejecta may be detectable by IceCube within a few years of operation, and will likely be detected with IceCube-Gen2. The neutrino signals coincident with gravitational waves would enable us to reveal the physical quantities of the choked jets even without electromagnetic signals.Comment: 12 pages, 5 figures, 2 tables, accepted for publication in PR

Gravitational Wave Memory of Gamma-Ray Burst Jets

Gamma-Ray Bursts (GRBs) are now considered as relativistic jets. We analyze the gravitational waves from the acceleration stage of the GRB jets. We show that (i) the point mass approximation is not appropriate if the opening half-angle of the jet is larger than the inverse of the Lorentz factor of the jet, (ii) the gravitational waveform has many step function like jumps, and (iii) the practical DECIGO and BBO may detect such an event if the GRBs occur in Local group of galaxy. We found that the light curve of GRBs and the gravitational waveform are anti-correlated so that the detection of the gravitational wave is indispensable to determine the structure of GRB jets.Comment: Revtex4, 10 pages, 6 figures, Fig.2 and Fig.3 replaced, minor changes to text in Sec.I and Sec.V, typos corrected, some reference added, Version to be published in PR

Late Engine Activity in Neutron Star Mergers and Its Cocoon: An Alternative Scenario for the Blue Kilonova

Follow-up observations of short gamma-ray bursts (sGRBs) have continuously unveiled late extended/plateau emissions, attributed to jet launch due to late engine activity, the nature of which remains enigmatic. Observations of GW170817 confirmed that sGRBs are linked to neutron star (NS) mergers, and discovered a kilonova (KN) transient. Nevertheless, the origin of the early "blue" KN in GW170817 remains unclear. Here, we investigate the propagation of late jets in the merger ejecta. By analytically modeling jet dynamics, we determine the properties of the jet heated cocoon, and estimate its cooling emission. Our results reveal that late jets generate significantly brighter cocoons compared to prompt jets, primarily due to reduced energy loss by adiabatic cooling. Notably, with typical late jets, emission from the cocoon trapped inside the ejecta can reproduce the blue KN emission. We estimate that the forthcoming Einstein Probe mission will detect the early cocoon emission with a rate of $\sim 2.1_{-1.6}^{+3.2}$ yr$^{-1}$, and that optical/UV follow-ups in the LIGO-VIRGO-KAGRA O5 run will be able to detect $\sim 1.0_{-0.7}^{+1.5}$ cocoon emission events. As an electromagnetic counterpart, this emission provides an independent tool to probe NS mergers in the Universe, complementing insights from sGRBs and gravitational waves.Comment: 31 pages, 7 figures, and 1 table. Accepted for publication in The Astrophysical Journa

Relativistic stars with poloidal and toroidal magnetic fields and meridional flow

We investigate stationary axisymmetric configurations of magnetized stars in the framework of general relativistic ideal magnetohydrodynamics. Our relativistic stellar model incorporates a toroidal magnetic field and meridional flow in addition to a poloidal magnetic field for the first time. The magnetic field and meridional flow are treated as perturbations, but no other approximation is made. We find that the stellar shape can be prolate rather than oblate when a toroidal field exists. We also find that, for fixed baryonic mass and total magnetic helicity, more spherical the star is, lower the energy it has. Further, we find two new types of the frame dragging effect which differ from the standard one in a rotating star or Kerr geometry. They may violate the reflection symmetry about the equatorial plane.Comment: 22 pages, 8 figures, 2 tables, emulateapj.cls used, accepted for publication in Ap

Napabucasin plus nab-paclitaxel with gemcitabine versus nab-paclitaxel with gemcitabine in previously untreated metastatic pancreatic adenocarcinoma: an adaptive multicentre, randomised, open-label, phase 3, superiority trial

Adenocarcinoma; Napabucasin; Pancreatic cancerAdenocarcinoma; Napabucasin; Càncer de pàncreesAdenocarcinoma; Napabucasin; Cáncer de páncreasBackground Compared with normal cells, tumour cells contain elevated levels of reactive oxygen species (ROS). Increased levels of the antioxidant protein NAD(P)H:quinone oxidoreductase 1 (NQO1) and phosphorylated signal transducer and activator of transcription 3 (pSTAT3) correlate negatively with the survival of patients with pancreatic cancer. Napabucasin is an investigational, orally administered ROS generator bioactivated by NQO1. Methods In the open-label, phase 3 CanStem111P study (NCT02993731), adults with previously untreated metastatic pancreatic adenocarcinoma (mPDAC) were randomised (1:1) to napabucasin plus nab-paclitaxel with gemcitabine or nab-paclitaxel with gemcitabine alone. The primary endpoint was overall survival (OS). In exploratory analyses, OS was evaluated in the subgroup of patients with tumours positive for pSTAT3 (biomarker-positive). Findings Between 30 January 2017 and 20 February 2019, a total of 1779 patients were screened across 165 study sites in Austria, Australia, Belgium, Canada, China, Czech Republic, France, Germany, Italy, Japan, Korea, Netherlands, Poland, Portugal, Russia, Singapore, Spain, Taiwan, Ukraine, and the US. Of the 565 and 569 patients randomised to the napabucasin and control treatment arms, respectively, 206 and 176 were biomarker-positive. Median (95% confidence interval [CI]) OS in the napabucasin and control treatment arms was 11.4 (10.5–12.2) and 11.7 (10.7–12.7) months, respectively (hazard ratio, 1.07; 95% CI, 0.93–1.23). Due to the lack of OS improvement in the napabucasin arm, CanStem111P was terminated due to futility. In the biomarker-positive subgroup, no difference between treatment arms was found for OS. Grade ≥3 adverse events were reported in 85.4% and 83.9% of napabucasin-treated and control-treated patients, respectively. The incidence of gastrointestinal-related grade ≥3 events was higher with napabucasin (diarrhoea: 11.6% vs 4.9%; abdominal pain: 10.0% vs 4.8%). Interpretation Our findings suggested that although the addition of napabucasin to nab-paclitaxel with gemcitabine did not improve efficacy in patients with previously untreated mPDAC, the safety profile of napabucasin was consistent with previous reports. CanStem111P represents the largest cohort of patients with mPDAC administered nab-paclitaxel with gemcitabine in the clinical trial setting. Our data reinforce the value of nab-paclitaxel plus gemcitabine as a platform for novel therapeutics approaches in mPDAC.This study was supported by Sumitomo Pharma Oncology, Inc