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the amount and configuration of land on a synchronously rotating, habitable-zone rocky planet can have a substantial impact on its climate. in a previous study, we showed using the 3d circulation model exoplasim that surface temperature can vary by up to 20 k, and atmospheric humidity can vary by several orders of magn... | influence of dayside land on climates and transit spectra of synchronously rotating rocky planets |
introduction: planets that retain a primordial, h-he dominated atmosphere can have hydrogen act as a greenhouse gas: the collision induced absorption (cia) of infra-red light increases with pressure. this mechanism could replace regular greenhouse gasses in exoplanets to allow warm enough temperatures for a liquid wate... | potential long-term habitable conditions on planets with primordial h-he atmospheres. |
climate modeling has shown that tidal locking, particularly of terrestrial exoplanets orbiting m-dwarfs, can lead unique atmospheric dynamics and surface conditions. however, chaotic libration and rotation induced by planetary interactions in compact planetary systems may destabilize attendant exoplanets away from sync... | combining 3d n-body simulation and climate modeling to decipher the climates of exoplanets in compact multi-planet systems |
energetic particles, such as stellar energetic particles and galactic cosmic rays, are an important part of space weather for exoplanets orbiting cool stars and the young earth. energetic particles bombard exoplanetary atmospheres, leading to unique chemical effects that may be detectable with jwst. the flux of energet... | the interaction of energetic particles with the winds of cool stars |
planned and future direct imaging missions, such as roman and the large space-based infrared/optical/ultraviolet (ir/o/uv) telescope prioritized in astro2020 will have the instrumentation capable of imaging the reflected light from exoplanets. while current direct imaging surveys probe the thermal emission of young, gi... | leveraging photometry for deconfusion of directly imaged multi-planet systems |
in order to recognize a habitable exoplanet from future observed spectra, we present new model reflected spectra and geometric albedo for modern and prebiotic (∼3.9 ga) earth-like exoplanets orbiting within the habitable zone of stars of spectral types f, g, k and m. we compute this for various atmospheric and surface ... | new models of reflection spectra for terrestrial exoplanets: present and prebiotic earth orbiting around stars of different spectral types |
the astro2020 decadal survey recommended a "future large ir/o/uv telescope optimized for observing habitable exoplanets and general astrophysics" that would "search for biosignatures from a robust number of about 25 habitable zone [exo]planets," now dubbed the habitable worlds observatory (hwo). the search for biosigna... | exo-earth yield of a 6m space telescope in the near-infrared |
the launch of the james webb space telescope (jwst) in december 2021 opens up the possibility of studying the composition of exoplanetary atmospheres in habitable zones, such as trappist-1e, in the near future. with the help of numerical models of the exoplanetary atmospheres, the observations and the processes behind ... | investigation of the influence of stellar particle events and galactic cosmic rays on the atmosphere of trappist-1e |
atmospheric escape shapes the fate of exoplanets, with statistical evidence for atmospheric mass loss imprinted across the mass-radius-insolation distribution. the habitable zone planet finder (hpf) spectrograph exospheres program aims to expand the search across a diverse range of planet and host star properties via t... | a large and variable leading tail of helium in hat-p-67b, a sub-saturn undergoing runaway inflation |
toi-700 d is the first earth-sized planet in the habitable zone (hz) discovered by the transiting exoplanet survey satellite. here, we assess whether a venus-like exoplanet at the toi-700 d location could retain an atmosphere for a time comparable to the age of the host star based on multispecies magnetohydrodynamics s... | study of atmospheric ion escape from exoplanet toi-700 d: venus analogs |
the existence of an earth-like habitat (defined as a rocky exoplanet within the habitable zone of complex life that hosts an n2-o2-dominated atmosphere with minor amounts of co2) is depending on a certain set of known (and, potentially, unknown) astrophysical and geophysical requirements that have to be met to allow fo... | the host star as a crucial factor for the prevalence of earth-like habitats |
the recently discovered super-earth lp 890-9 c is an intriguing target for atmospheric studies as it transits a nearby, low-activity late-type m-dwarf star at the inner edge of the habitable zone. its position at the runaway greenhouse limit makes it a natural laboratory to study the climate evolution of hot rocky plan... | 3d global climate model of an exo-venus: a modern venus-like atmosphere for the nearby super-earth lp 890-9 c |
a key objective of the upcoming habitable worlds observatory (hwo) is to search for habitable and inhabited planets. the astro2020 decadal survey recommended that the mission should be capable of searching for biosignatures in the atmospheres of roughly 25 habitable planets, and the nasa exoplanet exploration program (... | maximizing precursor knowledge of potential targets for the habitable worlds observatory |
when a planet has a strong dipole magnetic field and rapid rotation, superposition of the stellar wind induced and corotation electric fields results in the tear-drop-shaped region of the closed drift, where planetary ionized atmosphere can fill the magnetic flux tubes along the field lines. the region is characterized... | plasmasphere formation at terrestrial rocky exoplanets around m-dwarf stars and its detectability: possible evidence for the intrinsic magnetic field and thick atmosphere |
bow shocks are ubiquitous astrophysical phenomena resulting from the supersonic passage of an object through a gas. recently, pre-transit absorption in uv metal transitions of the hot jupiter exoplanets hd 189733b and wasp12-b have been interpreted as being caused by material compressed in a planetary bow shock. here w... | optical hydrogen absorption consistent with a bow shock leading the hot jupiter hd 189733b |
for temperate exoplanets orbiting m dwarf hosts, the proximity of the habitable zone to the star necessitates careful consideration of tidal effects. spin synchronization of the planetary orbital period and rotation period is a common assumption for habitable zone planets across the entire m spectral type. this predict... | plausibility of capture into high-obliquity states for exoplanets in the m dwarf habitable zone |
exoplanet imaging has thus far enabled studies of wide-orbit ($>$10 au) giant planet ($>$2 jupiter masses) formation and giant planet atmospheres, with future 30 meter-class extremely large telescopes (elts) needed to image and characterize terrestrial exoplanets. however, current state-of-the-art exoplanet imagi... | first laboratory demonstration of real-time multi-wavefront sensor single conjugate adaptive optics |
m dwarfs show the highest rocky planet occurrence among all spectral types, in some instances within the habitable zone. because some of them are very active stars, they are often subject to frequent and powerful flaring, which can be a double-edged sword in regard of exoplanet habitability. on one hand, the increased ... | observing m dwarfs uv and optical flares from a cubesat and their implications for exoplanets habitability |
the far-side array for radio science investigations of the dark ages and exoplanets (farside) is a proposed mission concept to the lunar far side that seeks to deploy and operate an array of 128 dual-polarization, dipole antennas over a region of 100 square kilometers. the resulting interferometric radio telescope woul... | how to deploy a 10-km interferometric radio telescope on the moon with just four tethered robots |
the proxima centauri planetary system (proxima hereafter), the nearest neighbor to our own solar system at 1.3 pc, consists of three confirmed exoplanets. the second, proxima b, is a likely super-earth residing within the circumstellar habitable zone. we analyze the stability of the two inner planets—proxima d and b—us... | orbital dynamics of the proxima centauri system |
the dozens of rocky exoplanets discovered in the circumstellar habitable zone (chz) currently represent the most suitable places to host life as we know it outside the solar system. however, the presumed presence of liquid water on the chz planets does not guarantee suitable environments for the emergence of life. acco... | the ultraviolet habitable zone of exoplanets |
without aerobic life, the simultaneous presence of n2 and o2 in the earth's atmosphere, as on any other planet, would be chemically incompatible over geologic timescales. the existence of an n2-o2-dominated atmosphere on an exoplanet would, hence, not only constitute a strong biosignature of aerobic life. it would also... | eta earth revisited: how many earth-like habitats might there be in the milky way? |
we are living in an extremely exciting era for exoplanet science: astronomers have detected nearly 5000 confirmed planets and we have begun to understand the links between stellar properties, planet compositions, system architectures, and formation histories. recognizing the compelling nature of the quest for other wor... | a trio of multiplanet systems and pathways to habitable worlds |
one of the most exciting scientific challenges is to detect earth-like planets in the habitable zones of other stars in the galaxy and search for evidence of life. during the past 20 years the detection of exoplanets, orbiting stars beyond our own, has moved from science fiction to science fact. from the first handful ... | the search for living worlds and the connection to our cosmic origins |
the "radius valley" is a feature in the short-period, small exoplanet population in kepler and k2 data showing an abundance of super-earths (1-2 r⊕) and mini-neptunes (2-3.5 r⊕), with a relatively scarce population of intermediate-sized planets between the two. by employing updated stellar properties and implementing r... | the population of earths and super-earths into the habitable zone |
m-dwarfs are common stellar hosts of habitable-zone exoplanets. near-uv (nuv) radiation can severely impact the atmospheric and surface conditions of such planets, making the characterization of nuv flaring activity a key aspect in determining habitability. we use archival data from the galaxy evolution explorer (galex... | a census of near-uv m-dwarf flares using archival galex data and the gphoton2 pipeline |
results from nasa’s kepler mission and other recent exoplanet surveys have demonstrated that potentially habitable exoplanets are relatively common, especially in the case of low-mass stellar hosts. the next key question that must be addressed for such planets is whether or not these worlds are actually habitable, impl... | characterizing exoplanet habitability with emission spectroscopy |
neid is a nasa & us nsf funded ultra-stable, optical spectrometer designed to achieve radial velocity (rv) precision on the order of 10cm/s. achieving this level of measurement precision requires extreme thermo-mechanical stability within the instrument which we achieve by maintaining a vacuum on the order of micro... | design and performance of neid ultra-stable environmental control system |
venus is the most earth-like planet in the solar system in terms of its size, mass, and bulk composition, yet the surface conditions of earth and its sister world could not be more different. venus has the hottest terrestrial surface in the solar system, yet it may once have hosted oceans in its deep past as indicated ... | venus: the exoplanet in our backyard |
we study the habitability of the two 1.5±0.4 earth-mass planets, recently detected by the carmenes collaboration, around the ultra-cool nearby m dwarf teegarden's star. with orbital periods of 4.9 and 11.4 days, both planets are likely to be within the habitable zone and tidally locked. they are among the most earth-li... | habitability of the teegarden's star planets |
the habitable zone gallery 2.0 provides new and improved visualization and data analysis tools to the exoplanet habitability community and beyond. modules include interactive habitable zone plotting and downloadable 3d animations. | the habitable zone gallery 2.0: the online exoplanet system visualization suite |
recent studies indicate that habitable zone planets around sun-like stars can be tidally-locked (barnes et al. 2017). it is plausible that earth-like planets around g-dwarfs, which are the primary exoplanet targets for future nasa concept missions like the habitable exoplanet imaging mission (habex) & the large ult... | the impact of planetary rotation rate on the reflectance spectrum of terrestrial exoplanets around sun-like stars |
saltus (single aperture large telescope for universe studies) is a probe mission concept that employs a radiatively cooled, 20 meter inflatable aperture and cryogenic detectors to better understand our cosmic origins and the possibility of life elsewhere. the science objectives of saltus are to: 1) trace astrochemical ... | single aperture large telescope for universe studies (saltus) |
in this thesis, we investigated the extreme precision radial velocity (eprv) problem by solving both the instrumental systematics and the stellar activity contaminations with the purpose of de- tecting earth-like planets orbiting within to the habitable zones of sun-like stars. we developed several pieces of codes dedi... | improving the rv precision to detect the earth's twins around the sun's siblings |
in this work, we consider the potential of cometary impacts to deliver complex organic molecules and the prebiotic building blocks required for life to rocky exoplanets. numerical experiments have demonstrated that for these molecules to survive, impacts at very low velocities are required. this work shows that for com... | can comets deliver prebiotic molecules to rocky exoplanets? |
the temperate rocky exoplanets that will be best characterized with future observations orbit m-dwarf stars. due to their close-in orbits, these planets are expected to be tidally locked to their host stars, with large day-night temperature and moisture contrasts and climates that are significantly different from that ... | favorability of hurricane genesis on tidally locked exoplanets orbiting m-dwarf stars |
to date, nearly all multi-wavelength modeling of long-duration γ-ray bursts has ignored synchrotron radiation from the significant population of electrons expected to pass the shock without acceleration into a power-law distribution. we investigate the effect of including the contribution of thermal, non-accelerated el... | thermal electrons in gamma-ray burst afterglows |
grb 190829a at z = 0.0785 is the fourth closest long grb ever detected by the neil gehrels swift observatory, and the third confirmed case with a very high-energy component. we present our multiwavelength analysis of this rare event, focusing on its early stages of evolution, and including data from swift, the master g... | the early afterglow of grb 190829a |
the nearest grb 170817a provided an opportunity to probe the angular structure of the jet of this short gamma-ray burst (sgrb), by using its off-axis observed afterglow emission. it is investigated that whether the afterglow-constrained jet structures can be consistent with the luminosity of the prompt emission of grb ... | joint constraint on the jet structure from the short grb population and grb 170817a |
motivated by the detection of very-high-energy (vhe) gamma rays deep in the afterglow emission of a gamma-ray burst (grb), we revisit predictions of the maximum energy to which electrons can be accelerated at a relativistic blast wave. acceleration at the weakly magnetized forward shock of a blast wave can be limited b... | the implications of tev-detected grb afterglows for acceleration at relativistic shocks |
we report the first detection of radio polarization of a gamma-ray burst (grb) afterglow with the first intensive combined use of telescopes in the millimeter and submillimeter ranges for grb 171205a. the linear polarization degree in the millimeter band at the subpercent level (0.27% ± 0.04%) is lower than those obser... | first detection of radio linear polarization in a gamma-ray burst afterglow |
well-sampled optical light curves of 50 gamma-ray bursts (grbs) with plateau features are compiled from the literature. by empirical fitting, we obtained the parameters of the optical plateaus, such as the decay slopes (α 1 and α 2), the break times (t b), and the corresponding optical fluxes (f b) at the break times. ... | the three-parameter correlations about the optical plateaus of gamma-ray bursts |
we present multi-wavelength follow-up campaigns by the astrosat czti and growth collaborations in search of an electromagnetic counterpart to the gravitational wave event gw 170104. at the time of the gw 170104 trigger, the astrosat czti field of view covered 50.3% of the sky localization. we do not detect any hard x-r... | a tale of two transients: gw 170104 and grb 170105a |
the afterglow emission from gamma-ray bursts (grbs) is believed to originate from a relativistic blast wave driven into the circumburst medium. although the afterglow emission from radio up to x-ray frequencies is thought to originate from synchrotron radiation emitted by relativistic, non-thermal electrons accelerated... | inverse compton signatures of gamma-ray burst afterglows |
an important constraint for galaxy evolution models is how much gas resides in galaxies, in particular, at the peak of star formation z = 1-3. we attempt a novel approach by letting long-duration gamma ray bursts (lgrbs) x-ray their host galaxies and deliver column densities to us. this requires a good understanding of... | galaxy gas as obscurer - i. grbs x-ray galaxies and find an nh3∝ m_{star} relation |
at 2022cmc is a luminous optical transient (νlν ≳ 1045 erg s-1) accompanied by decaying non-thermal x-rays (peak duration tx ≲ days and isotropic energy ex,iso ≳ 1053 erg) and a long-lived radio/mm synchrotron afterglow, which has been interpreted as a jetted tidal disruption event (tde). both an equipartition analysis... | synchrotron afterglow model for at 2022cmc: jetted tidal disruption event or engine-powered supernova? |
we present a spectropolarimetric analysis of grb 171010a using data from astrosat, fermi, and swift to provide insights into the physical mechanisms of the prompt radiation and jet geometry. the prompt emission from grb 171010a was very bright (fluence >10-4 erg cm-2) and had a complex structure that was composed of... | astrosat-czti detection of variable prompt emission polarization in grb 171010a |
based on the early-year observations from neil gehrels swift observatory, liang et al. performed a systematic analysis for the shallow decay component of gamma-ray bursts (grbs) x-ray afterglow, in order to explore its physical origin. here we revisit the analysis with an updated sample (with swift/xrt grbs between 200... | the shallow decay segment of grb x-ray afterglow revisited |
we consider here a proton-synchrotron model to explain the magic observation of grb 190114c afterglow in the energy band of 0.2-1 tev, while the x-ray spectra are explained by electron-synchrotron emission. given the uncertainty of the particle acceleration process, we consider several variations of the model, and show... | proton synchrotron origin of the very-high-energy emission of grb 190114c |
gamma-ray bursts (grbs) are fascinating extragalactic objects. they represent a fantastic opportunity to investigate unique properties not exhibited in other sources. multiwavelength afterglow observations from some short- and long-duration grbs reveal an atypical long-lasting emission that evolves differently from the... | modeling gamma-ray burst afterglow observations with an off-axis jet emission |
gamma-ray bursts (grbs) are detectable in the γ-ray band if their jets are oriented toward the observer. however, for each grb with a typical θjet, there should be ~2/θ2jet bursts whose emission cone is oriented elsewhere in space. these off-axis bursts can eventually be detected when, due to the deceleration of their ... | unveiling the population of orphan γ-ray bursts |
we present the discovery of the fading radio transient first j153350.8+272729. the source had a maximum observed 5 ghz radio luminosity of 8 × 1039 erg s-1 in 1986, but by 2019 had faded by a factor of nearly 400. it is located at the center of a galaxy (sdss j153350.89+272729) at 147 mpc, which shows weak type ii seyf... | first j153350.8+272729: the radio afterglow of a decades-old tidal disruption event |
gamma-ray bursts (grbs) are the most powerful explosions in the universe. how efficiently the jet converts its energy to radiation is a long-standing problem, which is poorly constrained. the standard model invokes a relativistic fireball with a bright photosphere emission component. a definitive diagnosis of grb radia... | a cosmological fireball with 16% gamma-ray radiative efficiency |
observations of tev emission from early gamma-ray burst (grb) afterglows revealed the long sought for inverse compton (ic) upscattering of the lower energy synchrotron. however, it turned out that the long hoped for ability to easily interpret the synchrotron self-compton (ssc) spectra didn't materialize. the tev emiss... | analytic modelling of synchrotron self-compton spectra: application to grb 190114c |
we present an implementation of a self-consistent way of modelling synchrotron self-compton (ssc) effects in gamma-ray burst afterglows, with and without approximated klein-nishina suppressed scattering for the afterglow modelling code boxfit, which is currently based on pure synchrotron emission. we discuss the change... | modelling synchrotron self-compton and klein-nishina effects in gamma-ray burst afterglows |
a newly born magnetar is thought to be central engine of some long gamma-ray bursts (grbs). we investigate the evolution of the electromagnetic (em) emission from the magnetic dipole (md) radiation wind injected by spin-down of a newly born magnetar via both quadrupole gravitational-wave (gw) and md radiations. we show... | electromagnetic emission from newly born magnetar spin-down by gravitational-wave and magnetic dipole radiations |
within the framework of the external shock model of gamma-ray burst (grb) afterglows, we perform a morphological analysis of the early-optical light curves 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 ... | a morphological analysis of gamma-ray burst early-optical afterglows |
distinct x-ray plateau and flare phases have been observed in the afterglows of gamma-ray bursts (grbs), and most of them should be related to central engine activities. in this paper, we collect 174 grbs with x-ray plateau phases and 106 grbs with x-ray flares. there are 51 grbs that overlap in the two selected sample... | statistical analyses of the energies of x-ray plateaus and flares in gamma-ray bursts |
in recent years, dynamical relativistic jet simulation techniques have progressed to a point where it is becoming possible to fully numerically resolve gamma-ray burst (grb) blast-wave evolution across scales. however, the modelling of emission is currently lagging behind and limits our efforts to fully interpret the p... | gamma: a new method for modelling relativistic hydrodynamics and non-thermal emission on a moving mesh |
we extend previous work on gamma-ray burst afterglows involving hot thermal electrons at the base of a shock-accelerated tail. using a physically motivated electron distribution based on first-principles simulations, we compute the broadband emission from radio to tev gamma rays. for the first time, we present the effe... | a semianalytic afterglow with thermal electrons and synchrotron self-compton emission |
context. the origin of the prompt emission of gamma-ray bursts is highly debated. proposed scenarios involve various dissipation processes (shocks, magnetic reconnection, and inelastic collisions) above or below the photosphere of an ultra-relativistic outflow.aims: we search for observational features that could help ... | what can we learn from "internal plateaus"? the peculiar afterglow of grb 070110 |
the nature of the gamma-ray burst (grb) central engine still remains an enigma. entities widely believed to be capable of powering the extreme jets are magnetars and black holes. the maximum rotational energy that is available in a millisecond magnetar to form a jet is ∼1052 erg. we identify eight long grbs whose jet-o... | identifying black hole central engines in gamma-ray bursts |
the spin-down energy of millisecond magnetars has been invoked to explain x-ray afterglow observations of a significant fraction of short and long gamma-ray bursts. here, we extend models previously introduced in the literature, incorporating radiative losses with the spin-down of a magnetar central engine through an a... | interpreting the x-ray afterglows of gamma-ray bursts with radiative losses and millisecond magnetars |
recently, lhaaso reported the detection of the brightest-of-all-time grb 221009a, revealing the early onset of a tev afterglow. we analyze the spectral evolution of the x-ray/gamma-ray emission of grb 221009a measured by the fermi gamma-ray burst monitor (gbm) during the dips of two prompt emission pulses (i.e., interv... | grb 221009a: revealing a hidden afterglow during the prompt emission phase with fermi-gbm observations |
we present here a survey of high-ionization absorption lines in the afterglow spectra of long-duration gamma-ray bursts (grbs) obtained with the vlt/x-shooter spectrograph. our main goal is to investigate the circumburst medium in the natal regions of grbs. our primary focus is on the n vλλ 1238, 1242 line transitions,... | highly ionized metals as probes of the circumburst gas in the natal regions of gamma-ray bursts |
the prompt emission of low-luminosity gamma-ray bursts (llgrbs) indicates that these events originate from a relativistic shock breakout. in this case, we can estimate, based on the properties of the prompt emission, the energy distribution of the ejecta. we develop a general formalism to estimate the afterglow produce... | the afterglow of a relativistic shock breakout and low-luminosity grbs |
the extinction profiles in gamma-ray burst (grb) afterglow spectral energy distributions (seds) are usually described by the small magellanic cloud (smc)-type extinction curve. in different empirical extinction laws, the total-to-selective extinction, rv, is an important quantity because of its relation to dust grain s... | vlt/x-shooter grbs: individual extinction curves of star-forming regions |
grb 110721a was detected by the gamma-ray burst monitor and the large area telescope (lat) on board the fermi satellite and the gamma-ray burst polarimeter on board the ikaros solar mission. previous analysis of this burst showed: (i) a linear polarization signal with position angle stable ({φ }p=160^\circ +/- 11) and ... | modeling the high-energy emission in grb 110721a and implications on the early multiwavelength and polarimetric observations |
very recently xue et al. reported an important detection of the x-ray transient, cdf-s xt2, whose light curve is analogous to x-ray plateau features of gamma-ray burst afterglows. they suggested that this transient is powered by a remnant stable magnetar from a binary neutron star merger because several pieces of evide... | on the properties of a newborn magnetar powering the x-ray transient cdf-s xt2 |
many gamma-ray bursts are followed by periods of extended emission. at least in some cases, the burst afterglow may be powered by a rapidly rotating, highly magnetized neutron star, which spins down due to electromagnetic and gravitational-wave emission. such a remnant is likely to strongly precess in the early stages ... | evidence for magnetar precession in x-ray afterglows of gamma-ray bursts |
the origin of the x-ray afterglows of gamma-ray bursts has regularly been debated. we fit both the fireball-shock and millisecond-magnetar models of gamma-ray bursts to the x-ray data of grb 130603b and 140903a. we use bayesian model selection to answer the question of which model best explains the data. this is depend... | x-ray afterglows of short gamma-ray bursts: magnetar or fireball? |
we study an extensive sample of 87 gamma-ray bursts (grbs) for which there are well-sampled and simultaneous optical and x-ray light curves. we extract the cleanest possible signal of the afterglow component and compare the temporal behaviors of the x-ray light curve, observed by swift xrt, and optical data, observed b... | a correlated study of optical and x-ray afterglows of grbs |
the afterglows to gamma-ray bursts (grbs) are due to synchrotron emission from shocks generated as an ultrarelativistic outflow decelerates. a forward and a reverse shock will form, however, where emission from the forward shock is well studied as a potential counterpart to gravitational wave-detected neutron star merg... | reverse shocks in the relativistic outflows of gravitational wave-detected neutron star binary mergers |
short gamma-ray bursts (grbs) are believed to be produced by relativistic jets from mergers of neutron stars (nss) or nss and black-holes (bhs). if the lorentz-factors γ of jets from compact stellar mergers follow a similar power-law distribution to those observed for other high-energy astrophysical phenomena (e.g., bl... | low-γ jets from compact stellar mergers: candidate electromagnetic counterparts to gravitational wave sources |
grb 130427a was the brightest gamma-ray burst detected in the last 30 yr. with an equivalent isotropic energy output of 8.5 × 1053 erg and redshift z = 0.34, it uniquely combined very high energetics with a relative proximity to earth. as a consequence, its x-ray afterglow has been detected by sensitive x-ray observato... | the 80 ms follow-up of the x-ray afterglow of grb 130427a challenges the standard forward shock model |
the electromagnetic (em) follow-up of a gravitational-wave (gw) event requires scanning a wide sky region, defined by the so-called “skymap,” to detect and identify a transient counterpart. we propose a novel method that exploits the information encoded in the gw signal to construct a “detectability map,” which represe... | where and when: optimal scheduling of the electromagnetic follow-up of gravitational-wave events based on counterpart light-curve models |
the detection of grb 180722b and grb 190114c in sub-tev gamma-rays has opened up a new window to study gamma-ray bursts in high-energy gamma-rays. recently it has been shown that the synchrotron and inverse compton processes are responsible for the production of these high-energy gamma-rays during the afterglow. here, ... | origin of sub-tev afterglow emission from gamma-ray bursts grb 190114c and grb 180720b |
the x-ray afterglow of many gamma-ray bursts (grbs) exhibits a plateau phase before the normal power-law decay stage, which may be related to continued activities of the central engine. tang et al. collected 174 such grbs and confirmed the so-called l-t-e correlation which involves three key parameters, i.e., the isotr... | pseudo-redshifts of gamma-ray bursts derived from the l-t-e correlation |
optical rebrightenings in the afterglows of some gamma-ray bursts (grbs) are unexpected within the framework of the simple external shock model. while it has been suggested that the central engines of some grbs are newly born magnetars, we aim to relate the behaviors of magnetars to the optical rebrightenings. a newly ... | imprints of electron-positron winds on the multiwavelength afterglows of gamma-ray bursts |
we report early optical linear polarization observations of two gamma-ray bursts made with the master robotic telescope network. we found the minimum polarization for grb 150301b to be 8 per cent at the beginning of the initial stage, whereas we detected no polarization for grb 150413a either at the rising branch or af... | early polarization observations of the optical emission of gamma-ray bursts: grb 150301b and grb 150413a |
we present observations by the fermi gamma-ray space telescope gamma-ray burst monitor (gbm) of the nearby (z = 0.55) grb 101219b. this burst is a long grb, with an associated supernova and with a blackbody (bb) component detected in the early afterglow observed by the swift x-ray telescope (xrt). here we show that the... | evidence for jet launching close to the black hole in grb 101219b—a fermi grb dominated by thermal emission |
grb 160625b is an extremely bright grb with three distinct emission episodes. by analyzing its data observed with the gamma-ray burst monitor (gbm) and large area telescope (lat) on board the fermi mission, we find that a multicolor blackbody (mbb) model can be used to fit very well the spectra of the initial short epi... | extremely bright grb 160625b with multiple emission episodes: evidence for long-term ejecta evolution |
context. short-duration gamma-ray bursts (grbs) with extended emission form a subclass of short grbs, comprising about 15% of the short-duration sample. afterglow detections of short grbs are also rare (about 30%) because of their lower luminosity.aims: we present a multiband data set of the short burst with extended e... | long optical plateau in the afterglow of the short grb 150424a with extended emission. evidence for energy injection by a magnetar? |
we report the lowest-frequency measurements of gamma-ray burst (grb) 171205a with the upgraded giant metrewave radio telescope (ugmrt) covering a frequency range of 250-1450 mhz and a period of 4-937 days. it is the first grb afterglow detected in the 250-500 mhz frequency range and the second brightest grb detected wi... | 1000 days of the lowest-frequency emission from the low-luminosity grb 171205a |
we present the first results from a recently concluded study of grbs at z ≳ 5 with the karl g. jansky very large array (vla). spanning 1 to 85.5 ghz and 7 epochs from 1.5 to 82.3 days, our observations of grb 140311a are the most detailed joint radio and millimeter observations of a grb afterglow at z ≳ 5 to date. in c... | a vla study of high-redshift grbs. i. multiwavelength observations and modeling of grb 140311a |
we use gamma-ray burst (grb) afterglow spectra observed with the vlt/x-shooter spectrograph to measure rest-frame extinction in grb lines-of-sight by modelling the broadband near-infrared (nir) to x-ray afterglow spectral energy distributions (seds). our sample consists of nine swift grbs, of which eight belong to the ... | spectrophotometric analysis of gamma-ray burst afterglow extinction curves with x-shooter |
we present a catalog of early-time (∼ {10}2-{10}4 s) photometry and polarimetry of all gamma-ray burst (grb) optical afterglows observed with the ringo2 imaging polarimeter on the liverpool telescope. of the 19 optical afterglows observed, the following nine were bright enough to perform photometry and attempt polarime... | polarimetry and photometry of gamma-ray bursts with ringo2 |
studies of gamma-ray bursts (grbs) and their multiwavelength afterglows have led to insights in electron acceleration and emission properties from relativistic, high-energy astrophysical sources. broad-band modelling across the electromagnetic spectrum has been the primary means of investigating the physics behind thes... | constraints on electron acceleration in gamma-ray bursts afterglows from radio peaks |
gamma-ray bursts (grbs) are very energetic cosmological transients. long grbs are usually associated with type ib/c supernovae (sne), and we refer to them as grb-sne. since the associated sn for a given grb is observed only at low redshift, a possible selection effect exists when we consider intrinsically faint sources... | the quest for new correlations in the realm of the gamma-ray burst-supernova connection |
gamma-ray bursts (grbs) are the strongest explosions in the universe, which due to their extreme character likely involve some of the strongest magnetic fields in nature. this review discusses the possible roles of magnetic fields in grbs, from their central engines, through the launching, acceleration and collimation ... | gamma-ray bursts as sources of strong magnetic fields |
grb 170817a, the first short gamma-ray burst (sgrb) to be detected in coincidence with a gravitational wave signal, demonstrated that merging binary neutron star (bns) systems can power collimated ultra-relativistic jets, and in turn, produce sgrbs. moreover, it revealed that sgrb jets possess an intrinsic angular stru... | jet-environment interplay in magnetized binary neutron star mergers |
it was proposed that a remnant stable magnetar could be formed in a binary neutron-star merger, leading to a fast x-ray transient (fxt) that can last for thousands of seconds. recently, xue et al. suggested that cdf-s xt2 was exactly such a kind of source. if confirmed, such emission can be used to search for electroma... | discovery of three candidate magnetar-powered fast x-ray transients from chandra archival data |
we report the early discovery of the optical afterglow of gamma-ray burst (grb) 140801a in the 137 deg2 3-σ error-box of the fermi gamma-ray burst monitor (gbm). master is the only observatory that automatically reacts to all fermi alerts. grb 140801a is one of the few grbs whose optical counterpart was discovered sole... | the optical identification of events with poorly defined locations: the case of the fermi gbm grb 140801a |
since the gravitational wave event gw170817 and gamma-ray burst gw170817a, there have been numerous studies constraining the burst properties through analysis of the afterglow light curves. most agree that the burst was viewed off-axis with a ratio of the observer angle to the jet angle (θ obs/θj ) between 4 and 6. we ... | revisiting the parameter space of binary neutron star merger event gw170817 |
gamma ray bursts (grbs) are a powerful probe of the high-redshift universe. we present a tool to estimate the detection rate of high-z grbs by a generic detector with defined energy band and sensitivity. we base this on a population model that reproduces the observed properties of grbs detected by swift, fermi and cgro... | accessing the population of high-redshift gamma ray bursts |
we work on a grb sample whose initial lorentz factors (γ0) are constrained by the afterglow onset method and the jet opening angles (θj) are determined by the jet break time. we confirm the γ0-eγ,iso correlation by liang et al. (2010), and the γ0-lγ,iso correlation by lü et al. (2012). furthermore, we find correlations... | lorentz factor - beaming corrected energy/luminosity correlations and grb central engine models |
the neil gehrels swift observatory (swift) has been in operation for 18 years. the ultra-violet/optical telescope (uvot) onboard swift was designed to capture the earliest optical/uv emission from gamma-ray bursts (grbs), spanning the first few minutes to days after the prompt gamma-ray emission. in this article, we pr... | swift/uvot: 18 years of long grb discoveries and advances |
the various stages of baryonic gamma-ray burst (grb) afterglow blast waves are reviewed. these are responsible for the afterglow emission from which much of our understanding of gamma-ray bursts derives. initially, the blast waves are confined to the dense medium surrounding the burster (stellar envelope or dense wind)... | gamma-ray burst afterglow blast waves |
the synchrotron external shock model predicts the evolution of the spectral (β) and temporal (α) indices during the gamma-ray burst (grb) afterglow for different environmental density profiles, electron spectral indices, electron cooling regimes, and regions of the spectrum. we study the relationship between α and β, t... | closure relations of gamma-ray bursts in high energy emission |
the spectrum of gamma-ray burst (grb) afterglows can be studied with color indices. here, we present a large comprehensive catalog of 70 grbs with multiwavelength optical transient data on which we perform a systematic study to find the temporal evolution of color indices. we categorize them into two samples based on h... | a large catalog of multiwavelength grb afterglows. i. color evolution and its physical implication |
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