Population III stars are believed to be rapidly-rotating sources with a mass range of hundreds to thousand of solar masses. Masses larger than 260 M$_\odot$ are expected to collapse resulting in central rotating Kerr black holes with large rotation parameter a. Due to particle-antiparticle asymmetry is small, we use the neutrino effective potential up to order $1/M_W^4$ in a magnetized plasma at the base of the ejecta to constrain the rotation parameter by means of neutrino oscillations. Additionally, we investigate the implications in the magnetic field, temperature and electron asymmetry.
Current models suggest gamma-ray bursts could be used as a way of probing Population III stars - the first stars in the early Universe. In this paper we use numerical simulations to demonstrate that late time radio observations of gamma-ray burst afterglows could provide a means of identifying bursts that originate from Population III stars, if these were highly massive, independently from their redshift. We then present the results from a pilot study using the Australia Telescope Compact Array at 17 GHz, designed to test the hypothesis that there may be Population III gamma-ray bursts amongst…
We discuss a model of Poynting-dominated gamma-ray bursts from the collapse of very massive first generation (pop. III) stars. From redshifts of order 20, the resulting relativistic jets would radiate in the hard X-ray range around 50 keV and above, followed after roughly a day by an external shock component peaking around a few keV. On the same timescales an inverse Compton component around 75 GeV may be expected, as well as a possible infra-red flash. The fluences of these components would be above the threshold for detectors such as Swift and Fermi, providing potentially valuable informatio…
Recent numerical simulations suggest that Population III (Pop III) stars were born with masses not larger than $\sim 100 M_{\odot}$ but typically $\sim 40M_{\odot}$. By self-consistently considering the jet generation and propagation in the envelope of these low mass Pop III stars, we find that a Pop III blue super giant star has the possibility to raise a gamma-ray burst (GRB) even though it keeps a massive hydrogen envelope. We evaluate observational characters of Pop III GRBs and predict that Pop III GRBs have the duration of $\sim 10^5$ sec in the observer frame and the peak luminosity of …
We present the optical luminosity function (LF) of gamma-ray bursts (GRBs) estimated from a uniform sample of 58 GRBs from observations with the Robotic Optical Transient Search Experiment III (ROTSE-III). Our GRB sample is divided into two sub-samples: detected afterglows (18 GRBs), and those with upper limits (40 GRBs). The $R$ band fluxes 100s after the onset of the burst for these two sub-samples are derived. The optical LFs at 100s are fitted by assuming that the co-moving GRB rate traces the star-formation rate. The detection function of ROTSE-III is taken into account during the fitting…
We investigate the propagation of accretion-powered jets in various types of massive stars such as Wolf-Rayet stars, light Population III (Pop III) stars, and massive Pop III stars, all of which are the progenitor candidates of Gamma-Ray Bursts (GRBs). We perform two dimensional axisymmetric simulations of relativistic hydrodynamics taking into account both the envelope collapse and the jet propagation (i.e., the negative feedback of the jet on the accretion). Based on our hydrodynamic simulations, we show for the first time that the accretion-powered jet can potentially break out relativistic…
We investigate the prospects of detecting radio afterglows from long Gamma-Ray Bursts (GRBs) from Population III (Pop III) progenitors using the SKA precursor instruments WMA (Murchison Widefield Array) and ASKAP (Australian SKA Pathfinder). We derive a realistic model of GRB afterglows that encompasses the widest range of plausible physical parameters and observation angles. We define the best case scenario of Pop III GRB energy and redshift distributions. Using probability distribution functions fitted to the observed microphysical parameters of long GRBs, we simulate a large number of Pop I…
The Prompt Emission of Gamma-Ray Bursts from Population III Stars
Oregon State University（俄勒冈州立大学）；NASA Goddard Space Flight Center（美国国家航空航天局戈达德太空飞行中心）；Stony Brook University（石溪大学）；Flatiron Institute（熨斗研究所）；Princeton University（普林斯顿大学）；Stanislaus State University（斯坦尼斯劳斯州立大学）
Future missions for long gammma-ray burst (GRB) observations at high redshift such as HiZ-GUNDAM and THESEUS will provide clue to the star formation history in our universe. In this paper focusing on high redshift (z>8) GRBs, we calculate the detection rate of long GRBs by future observations, considering both Population (Pop) I&II stars and Pop III stars as GRB progenitors. For the Pop I&II star formation rate (SFR), we adopt an up-to-date model of high-redshift SFR based on the halo mass function and dark matter accretion rate obtained from cosmological simulations. We show that the Pop I&II…
Gamma-ray bursts (GRBs) are ideal probes of the epoch of the first stars and galaxies. We review the recent theoretical understanding of the formation and evolution of the first (so-called Population III) stars, in light of their viability of providing GRB progenitors. We proceed to discuss possible unique observational signatures of such bursts, based on the current formation scenario of long GRBs. These include signatures related to the prompt emission mechanism, as well as to the afterglow radiation, where the surrounding intergalactic medium might imprint a telltale absorption spectrum. We…
Context: The last few decades has seen numerous studies dedicated to fine structures of type III radio bursts observed in the metric to decametric wavelengths. Majority of explanations of the structured radio emission involve the propagation of electron beam through the strongly inhomogeneous plasma in the low corona. Until now only few studies of single type III bursts with fine structures, observed in the hecto-kilometric wavelengths, were reported. Aims: Herein we report about existence of numerous structured type III radio bursts observed during the STEREO era by all three WAVES instrument…
We calculate the theoretical event rate of gamma-ray bursts (GRBs) from the collapse of massive first-generation (Population III; Pop III) stars. The Pop III GRBs could be super-energetic with the isotropic energy up to $E_{\rm iso} \gtrsim 10^{55-57}$ ergs, providing a unique probe of the high-redshift Universe. We consider both the so-called Pop III.1 stars (primordial) and Pop III.2 stars (primordial but affected by radiation from other stars). We employ a semi-analytical approach that considers inhomogeneous hydrogen reionization and chemical evolution of the intergalactic medium. We show …
We report on the polarization properties of two fast radio bursts (FRBs): 151230 and 160102 discovered in the SUrvey for Pulsars and Extragalactic Radio Bursts (SUPERB) at the Parkes radio telescope. FRB 151230 is observed to be 6 $\pm$ 11% circularly polarized and 35 $\pm$ 13 % linearly polarized with a rotation measure (RM) consistent with zero. Conversely, FRB 160102 is observed to have a circular polarization fraction of 30 $\pm$ 11 %, linear polarization fraction of 84 $\pm$ 15 % for RM = -221(6) rad m$^{-2}$ and the highest measured DM (2596.1 $\pm$ 0.3 pc cm$^{-3}$) for an FRB to date. …
To date, one repeating and many apparently non-repeating fast radio bursts have been detected. This dichotomy has driven discussions about whether fast radio bursts stem from a single population of sources or two or more different populations. Here we present the arguments for and against.
We analyze radio bursts observed in events with interacting/non-interacting CMEs that produced major SEPs (Ip $>$ 10 MeV) fromApril 1997 to December 2014.We compare properties of meter (m), deca-hectometer (DH) type II as well as DH type III bursts, and time lags for interacting-CME-associated (IC) events and non-interacting-CME-associated (NIC) events. About 70\% of radio emissions were observed in events of both types from meters to kilometers. We found high correlations between the drift rates and mid-frequencies of type II radio bursts calculated as the mean geometric between their startin…
Within the framework of the external shock model of gamma-ray bursts (GRBs) afterglows, we perform a morphological analysis of the early optical lightcurves to directly constrain model parameters. We define four morphological types, i.e. the reverse shock dominated cases with/without the emergence of the forward shock peak (Type I/ Type II), and the forward shock dominated cases without/with $ν_m$ crossing the band (Type III/IV). We systematically investigate all the Swift GRBs that have optical detection earlier than 500 s and find 3/63 Type I bursts (4.8%), 12/63 Type II bursts (19.0%), 30/6…
We study the release of energy during the gradual phase of a flare, characterized by faint bursts of non-thermal hard X-ray (HXR) emission associated with decimetric radio spikes and type III radio bursts starting at high frequencies and extending to the heliosphere. We characterize the site of electron acceleration in the corona and study the radial evolution of radio source sizes in the high corona. Imaging and spectroscopy of the HXR emission with Fermi and RHESSI provide a diagnostic of the accelerated electrons in the corona as well as a lower limit on the height of the acceleration regio…
By employing a simple semi-analytical star formation model where the formation rates of Population (Pop) I/II and III stars can be calculated, respectively, we account for the number distribution of gamma-ray bursts (GRBs) with high pseudo-redshifts that was derived from an empirical luminosity-indictor relationship. It is suggested that a considerable number of Pop III GRBs could exist in the present sample of Swift GRBs. By further combining the implication for the star formation history from the optical depth of the CMB photons, it is also suggested that only a very small fraction 0.6% of P…
A method is presented to limit the volumetric density of repeating fast radio bursts based on the number (or lack) of repeating bursts identified in a survey. The method incorporates the instantaneous sensitivity of the instrument, its beam pattern, and the dwell time per pointing, as well as the energy and timing distribution of repeat bursts. Applied to the Australian Square Kilometre Array Pathfinder's (ASKAP's) Commensal Real-time ASKAP Fast Transients (CRAFT) `lat50' survey, the presence of an FRB similar to FRB 121102 is excluded within a volume of $1.9 \cdot 10^6$ Mpc$^3$ at 95% confide…
We investigate the detectability of a proposed population of Gamma-Ray Bursts (GRBs) from the collapse of Population III (Pop III) stars. The James Webb Space Telescope (JWST) and Space Infrared telescope for Cosmology and Astrophysics (SPICA) will be able to observe the late time infrared afterglows. We have developed a new method to calculate their detectability, which takes into account the fundamental initial mass function (IMF) and formation rates of Pop III stars, from which we find the temporal variability of the afterglows and ultimately the length of time JWST and SPICA can detect the…
Type II bursts are thought to arise from instabilities in the accretion flow onto a neutron star in an X-ray binary. Despite having been known for almost 40 years, no model can yet satisfactorily account for all their properties. To shed light on the nature of this phenomenon and provide a reference for future theoretical work, we study the entire sample of Rossi X-ray Timing Explorer data of type II bursts from the Rapid Burster (MXB 1730-335). We find that type II bursts are Eddington-limited in flux, that a larger amount of energy goes in the bursts than in the persistent emission, that typ…
We propose a method for confirmation of the existence of Population III (Pop III) stars with massive black hole binaries as GW150914 in gravitational wave (GW) observation. When we get enough number of events, we want to determine which model is closer to reality, with and without Pop III stars. We need to prepare various "Pop I/II models" and various "Pop I/II/III models" and investigate which model is consistent with the events. To demonstrate our analysis, we simulate detections of GW events for some examples of population synthesis models with and without Pop III stars. We calculate the li…
We reconsider the model of neutrino production during the 'bright phase', first suggested in 1977, in the light of modern understanding of the role of Pop III stars and acceleration of particles in supernova shocks. We concentrate on the production of cosmogenic UHE neutrinos in supernova explosions that accompany the death of Pop III stars. Accelerated protons produce neutrinos in collisions with CMB photons. We deliberately use simplified assumptions which make our results transparent. Pop III stars are assumed to be responsible for the reionization of the universe as observed by WMAP. Since…
High time resolution radio surveys over the last few years have discovered a population of millisecond-duration transient bursts called Fast Radio Bursts (FRBs), which remain of unknown origin. FRBs exhibit dispersion consistent with propagation through a cold plasma and dispersion measures indicative of an origin at cosmological distances. In this paper we perform Monte Carlo simulations of a cosmological population of FRBs, based on assumptions consistent with observations of their energy distribution, their spatial density as a function of redshift and the properties of the interstellar and…
Metal-poor massive stars may typically end up their lives as blue supergiants (BSGs). Gamma-ray bursts (GRBs) from such progenitors could have ultra-long duration of relativistic jets. For example Population III (Pop III) GRBs at z ~ 10-20 might be observable as X-ray rich events with a typical duration of T_90 ~ 10^4(1+z) sec. Recent GRB111209A at z = 0.677 has an ultra long duration of T_90 ~ 2.5*10^4 sec so that it have been suggested that the progenitor might be a metal-poor BSGs in the local universe. Here, we suggest luminous UV/optical/infrared emissions associated with such a new class…
Many techniques for measuring neutron star radii rely on absolute flux measurements in the X-rays. As a result, one of the fundamental uncertainties in these spectroscopic measurements arises from the absolute flux calibrations of the detectors being used. Using the stable X-ray burster, GS 1826-238, and its simultaneous observations by Chandra HETG/ACIS-S and RXTE/PCA as well as by XMM-Newton EPIC-pn and RXTE/PCA, we quantify the degree of uncertainty in the flux calibration by assessing the differences between the measured fluxes during bursts. We find that the RXTE/PCA and the Chandra grati…
We present cm-band and mm-band afterglow observations of five long-duration $γ$-ray bursts (GRBs; GRB 130131A, 130420B, 130609A, 131229A, 140713A) with dust-obscured optical afterglow emission, known as "dark" GRBs. We detect the radio afterglow of two of the dark GRBs (GRB 130131A and 140713A), along with a tentative detection of a third (GRB 131229A) with the Karl G. Jansky Very Large Array (VLA). Supplemented by three additional VLA-detected dark GRBs from the literature, we present uniform modeling of their broadband afterglows. We derive high line-of-sight dust extinctions of $A_{V, \rm G…
Fast Radio Bursts (FRBs) are energetic, short, bright transients that occur frequently over the entire radio sky. The observational challenges following from their fleeting, generally one-off nature have prevented identification of the underlying sources producing the bursts. As the population of detected FRBs grows, the observed distributions of brightness, pulse width and dispersion measure now begin to take shape. Meaningful direct interpretation of these distributions is, however, made impossible by the selection effects that telescope and search pipelines invariably imprint on each FRB su…
Assuming that the early optical emission is dominated by the external reverse shock (RS) in the standard model of gamma-ray bursts (GRBs), we intend to constrain RS models with the initial Lorentz factor $Γ_0$ of the outflows based on the ROTSE-III observations. We consider two cases of the RS behavior: the relativistic shock and the non-relativistic shock. For homogeneous interstellar medium (ISM) and wind circum-burst environment, the constraints can be achieved by the fact that the peak flux $F_{\rm ν}$ at the RS crossing time should be lower than the observed upper limit $F_{\rm ν,limit}$.…
Observations of the solar corona and the solar wind discover that the solar wind is unsteady and originates from the impulsive events near the surface of the Sun's atmosphere. How solar coronal activities affect the properties of the solar wind is a fundamental issue in heliophysics. We report a simulation and theoretical investigation of how nanoflare accelerated electron beams affect the kinetic-scale properties of the solar wind and generate coherent radio emission. We show that nanoflare-accelerated electron beams can trigger a nonlinear electron two stream instability, which generates kin…
To probe this question, we perform a statistical analysis using the first Canadian Hydrogen Intensity Mapping Experiment Fast Radio Burst (CHIME/FRB) catalog and identify a few discriminant properties between repeating and non-repeating FRBs such as the repetition rate, duration, bandwidth, spectral index, peak luminosity, and potential peak frequency. If repeating and non-repeating FRBs belong to one population, their distribution distinctions for the repetition rate and duration can be explained by the selection effect due to the beamed emission as in Connor et al. (2020). However, we obtain…
The observed lightcurves and estimated sky rate of fast extragalactic x-ray transients (XRTs) discovered in archival Chandra data indicate that they belong to two distinct XRT populations. The first population of relatively short duration pulses, which typically last less than few minutes seems to be pulses of x-ray flashes (XRFs), which are nearby long duration gamma ray bursts viewed from far off axis. The second population of much longer pulses, which typically last hours, seems to be the early time afterglows of short gamma ray bursts (SGRBs) which are beamed away from Earth, as was shown …
[Zhang 2014] propose to redefine the true GRB central engine activity duration, $t_{\rm burst}$, by considering the contributions from the prompt $γ$-ray emission, X-ray flare and internal plateau features. With a comprehensive study on a large sample of Swift GRBs, it is shown that the $t_{\rm burst}$ distribution in the observer frame consists of a bimodal feature, suggesting the existence of a new population of ultra-long GRBs. In this work, we make a series of further studies on $t_{\rm burst}$: we update the Swift GRB sample up to June 2016; we investigate the properties of $t_{\rm burst}…
We show that a relativistic gamma-ray burst (GRB) jet can potentially pierce the envelope of very massive first generation star (Population III; Pop III) by using the stellar density profile to estimate both the jet luminosity (via accretion) and its penetrability. The jet breakout is possible even if the Pop III star has a supergiant hydrogen envelope without mass loss, thanks to the long-lived powerful accretion of the envelope itself. While the Pop III GRB is estimated to be energetic, E_{gamma,iso} ~ 10^{55} erg, the supergiant envelope hides the initial bright phase into the cocoon compon…
We study the properties of the population of optically dark events present in a carefully selected complete sample of bright Swift long gamma-ray bursts. The high level of completeness in redshift of our sample (52 objects out of 58) allow us to establish the existence of a genuine dark population and we are able to estimate the maximum fraction of dark burst events (~30%) expected for the whole class of long gamma-ray burst. The redshift distribution of this population of dark bursts is similar to the one of the whole sample. Interestingly, the rest-frame X-ray luminosity (and the de-absorbed…
Gamma-ray bursts (GRBs) are the ultimate cosmic lighthouses, capable of illuminating the universe at its earliest epochs. Could such events probe the properties of the first stars at z $\sim$ 20, the end of the cosmic Dark Ages? Previous studies of Population III GRBs only considered explosions in the diffuse relic H II regions of their progenitors, or bursts that are far more more energetic than those observed to date. But the processes that produce GRBs at the highest redshifts likely reset their local environments, creating much more complicated structures than those in which relativistic j…
Baryonification III: An accurate analytical model for the dispersion measure probability density function of fast radio bursts
Argelander-Institut für Astronomie, Universität Bonn（波恩大学阿根德天文学研究所）；Jodrell Bank Centre for Astrophysics, Department of Physics and Astronomy, The University of Manchester（曼彻斯特大学物理学与天文学系乔德雷尔银行天体物理学中心）；Institute for Particle Physics and Astrophysics, ETH Zurich（苏黎世联邦理工学院粒子物理与天体物理研究所）；Department of Astronomy and Oskar Klein Centre, AlbaNova, Stockholm University（斯德哥尔摩大学阿尔巴诺瓦天文学与奥斯卡·克莱因中心）；Department of Astrophysics, University of Zurich（苏黎世大学天体物理学系）；Universitäts-Sternwarte, Fakultät für Physik, Ludwig-Maximilians Universität München（慕尼黑大学物理学院大学天文台）；Excellence Cluster ORIGINS（卓越集群ORIGINS）
The detection rate of gamma-ray burst (GRB) afterglows is only ~30% at radio wavelengths, much lower than in the X-ray (~95%) or optical (~70%) bands. The cause of this low radio detection rate has previously been attributed to limited observing sensitivity. We use visibility stacking to test this idea, and conclude that the low detection rate is instead due to two intrinsically different populations of GRBs, radio bright and radio faint. We calculate that no more than 70% of GRB afterglows are truly radio bright, leaving a significant population of GRBs that lack a radio afterglow. These radi…
We show how the redshift and peak-flux distributions of gamma-ray bursts (GRBs) have an observation time dependence that can be used to discriminate between different burst populations. We demonstrate how observation time relations can be derived from the standard integral distributions and that they can differentiate between GRB populations detected by both the BATSE and \emph{Swift} satellites. Using \emph{Swift} data we show that a redshift--observation-time relation (log\,$Z$\,--\,log\,$T$) is consistent with both a peak-flux\,--\,observation time relation (log\,$P$\,--\,log\,$T$) and a st…
Population (Pop) III stars, first stars, or metal-free stars are made of primordial gas. We have examined if they can be dominant origins of merging binary black holes (BHs) and extremely metal-poor stars. The abundance pattern of EMP stars is helpful to trace back the properties of Pop III stars. We have confirmed previous arguments that the observed BH merger rate needs Pop III star formation efficiency 10 times larger than theoretically predicted values, while the cosmic reionization history still permits such a high Pop III star formation efficiency. On the other hand, we have newly found …
We perform population synthesis simulations for Population III (Pop III) coalescing binary neutron stars (NS-NSs), neutron star - black hole binaries (NS-BHs), and binary black holes (BH-BHs) which merge within the age of the universe. We found that the typical mass of Pop III BH-BHs is $\sim 30\ \rm{M}_{\odot}$ so that the inspiral chirp signal of gravitational waves can be detected up to z=0.28 by KAGRA, Adv. LIGO, Adv. Virgo and GEO network. Our simulations suggest that the detection rate of the coalescing Pop III BH-BHs is $140 (68) \cdot ({\rm SFR}_{\rm p}/10^{-2.5} \rm{M}_{\odot} {\rm yr…
The phenomena observed at the Sun have a variety of unique radio signatures that can be used to diagnose the processes in the solar atmosphere. The insights provided by radio obervations are further enhanced when they are combined with observations from space-based telescopes. This special issue demonstrates the power of combination methodology at work and provides new results on i) type I solar radio bursts and thermal emission to study active regions; ii) type II and IV bursts to better understand the structure of coronal mass ejections; iii)~non-thermal gyro-synchrotron and/or type III burs…
