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Academic literature on the topic 'Afterglow'

Author: Grafiati
Published: 4 June 2021
Last updated: 10 March 2023

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Journal articles on the topic "Afterglow"

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Lamb, Gavin P., Lorenzo Nativi, Stephan Rosswog, D. Alexander Kann, Andrew Levan, Christoffer Lundman, and Nial Tanvir. "Inhomogeneous Jets from Neutron Star Mergers: One Jet to Rule Them All." Universe 8, no. 12 (November 23, 2022): 612. http://dx.doi.org/10.3390/universe8120612.

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Using the resultant profiles from 3D hydrodynamic simulations of relativistic jets interacting with neutron star merger wind ejecta, we show how the inhomogeneity of energy and velocity across the jet surface profile can alter the observed afterglow lightcurve. We find that the peak afterglow flux depends sensitively on the observer’s line-of-sight, not only via the jet inclination but also through the jet rotation: for an observer viewing the afterglow within the GRB-bright jet core, we find a peak flux variability on the order <0.5 dex through rotational orientation and <1.3 dex for the polar inclination. An observed afterglow’s peak flux can be used to infer the jet kinetic energy, and where a top-hat jet is assumed, we find the range of inferred jet kinetic energies for our various model afterglow lightcurves (with fixed model parameters), covers ∼1/3 of the observed short GRB population. Additionally, we present an analytic jet structure function that includes physically motivated parameter uncertainties due to variability through the rotation of the source. An approximation for the change in collimation due to the merger ejecta mass is included and we show that by considering the observed range of merger ejecta masses from short GRB kilonova candidates, a population of merger jets with a fixed intrinsic jet energy is capable of explaining the observed broad diversity seen in short GRB afterglows.
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Boersma, O. M., J. van Leeuwen, E. A. K. Adams, B. Adebahr, A. Kutkin, T. Oosterloo, W. J. G. de Blok, et al. "A search for radio emission from double-neutron star merger GW190425 using Apertif." Astronomy & Astrophysics 650 (June 2021): A131. http://dx.doi.org/10.1051/0004-6361/202140578.

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Context. Detection of the electromagnetic emission from coalescing binary neutron stars (BNS) is important for understanding the merger and afterglow. Aims. We present a search for a radio counterpart to the gravitational-wave (GW) source GW190425, a BNS merger, using Apertif on the Westerbork Synthesis Radio Telescope (WSRT). Methods. We observed a field of high probability in the associated localisation region for three epochs at ΔT = 68, 90, 109 d post merger. We identified all sources that exhibit flux variations consistent with the expected afterglow emission of GW190425. We also looked for possible transients. These are sources that are only present in one epoch. In addition, we quantified our ability to search for radio afterglows in the fourth and future observing runs of the GW detector network using Monte Carlo simulations. Results. We found 25 afterglow candidates based on their variability. None of these could be associated with a possible host galaxy at the luminosity distance of GW190425. We also found 55 transient afterglow candidates that were only detected in one epoch. All of these candidates turned out to be image artefacts. In the fourth observing run, we predict that up to three afterglows will be detectable by Apertif. Conclusions. While we did not find a source related to the afterglow emission of GW190425, the search validates our methods for future searches of radio afterglows.
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Gottlieb, Ore, Ehud Nakar, and Tsvi Piran. "Detectability of neutron star merger afterglows." Monthly Notices of the Royal Astronomical Society 488, no. 2 (July 11, 2019): 2405–11. http://dx.doi.org/10.1093/mnras/stz1906.

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ABSTRACT VLBI and JVLA observations revealed that GW170817 involved a narrow jet (θj ≈ 4°) that dominated the afterglow peak at our viewing angle, θobs ≈ 20°. This implies that at the time of the afterglow peak, the observed signal behaved like an afterglow of a top-hat jet seen at θobs ≫ θj, and it can be modelled by analytic expressions that describe such jets. We use a set of numerical simulations to calibrate these analytic relations and obtain generic equations for the peak time and flux of such an afterglow as seen from various observing angles. Using the calibrated equations and the estimated parameters of GW170817, we estimate the detectability of afterglows from future double neutron star mergers during the Advanced LIGO/Virgo observation run O3. GW170817 took place at a relatively low-density environment. Afterglows of similar events will be detectable only at small viewing angles, θobs ≲ 20°, and only 20 per cent of the GW detections of these events will be accompanied by a detectable afterglow. At higher densities, more typical to sGRB sites, up to $70\,\rm{per\,cent}$ of the GW detections are expected to be followed by a detectable afterglow, typically at θobs ∼ 30°. We also provide the latest time one should expect an afterglow detection. We find that for typical parameters, if the jet emission had not been detected within about a year after the merger, it is unlikely to be ever detected.
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Aksulu, M. D., R. A. M. J. Wijers, H. J. van Eerten, and A. J. van der Horst. "A new approach to modelling gamma-ray burst afterglows: using Gaussian processes to account for the systematics." Monthly Notices of the Royal Astronomical Society 497, no. 4 (August 5, 2020): 4672–83. http://dx.doi.org/10.1093/mnras/staa2297.

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ABSTRACT The afterglow emission from gamma-ray bursts (GRBs) is a valuable source of information to understand the physics of these energetic explosions. The fireball model has become the standard to describe the evolution of the afterglow emission over time and frequency. Because of recent developments in the theory of afterglows and numerical simulations of relativistic outflows, we are able to model the afterglow emission with realistic dynamics and radiative processes. Although the models agree with observations remarkably well, the afterglow emission still contains additional physics, instrumental systematics, and propagation effects that make the modelling of these events challenging. In this work, we present a new approach to modelling GRB afterglows, using Gaussian processes (GPs) to take into account systematics in the afterglow data. We show that, using this new approach, it is possible to obtain more reliable estimates of the explosion and microphysical parameters of GRBs. We present fit results for five long GRBs and find a preliminary correlation between the isotropic energetics and opening angles of GRBs, which confirms the idea of a common energy reservoir for the kinetic energy of long GRBs.
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Zhu, Jin-Ping, Yuan-Pei Yang, Bing Zhang, He Gao, and Yun-Wei Yu. "Kilonova and Optical Afterglow from Binary Neutron Star Mergers. I. Luminosity Function and Color Evolution." Astrophysical Journal 938, no. 2 (October 1, 2022): 147. http://dx.doi.org/10.3847/1538-4357/ac8e60.

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Abstract In the first work of this series, we adopt a GW170817-like viewing-angle-dependent kilonova model and the standard afterglow model with a light-curve distribution based on the properties of cosmological short gamma-ray burst afterglows to simulate the luminosity functions and color evolution of both kilonovae and optical afterglow emissions from binary neutron star (BNS) mergers. We find that ∼10% of the nearly-on-axis afterglows are brighter than the associated kilonovae at the peak time. These kilonovae would be significantly polluted by the associated afterglow emission. Only at large viewing angles with sin θ v ≳ 0.20 , the electromagnetic signals of most BNS mergers would be kilonova-dominated and some off-axis afterglows may emerge at ∼5–10 days after the mergers. At a brightness dimmer than ∼23–24 mag, according to their luminosity functions, the number of afterglows is much larger than that of kilonovae. Because the search depth of the present survey projects is <22 mag, the number of afterglow events that are detected via serendipitous observations would be much higher than that of kilonova events, consistent with the current observations. For the foreseeable survey projects (e.g., Mephisto, WFST, and LSST), whose search depths can reach ≳23–24 mag, the detection rate of kilonovae could have the same order of magnitude as afterglows. We also find that it may be difficult to use the fading rate in a single band to directly identify kilonovae and afterglows among various fast-evolving transients by serendipitous surveys. However, the color evolution between the optical and infrared bands can identify them because the color evolution patterns of these phenomena are unique compared with those of other fast-evolving transients.
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Wang, X. G., E. W. Liang, L. Li, J. J. Wei, and B. Zhang. "Luminosity Distribution of Gamma-ray Burst Optical Afterglows." Proceedings of the International Astronomical Union 8, S290 (August 2012): 335–36. http://dx.doi.org/10.1017/s1743921312020285.

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AbstractWe derive the optical afterglow luminosity distributions at different epoches for gamma-ray bursts (GRBs) from a sample of 146 GRBs that have a well-sampled optical afterglow lightcurve, then explore the luminosity function of GRB optical afterglows using the Monte Carlo simulation. We show that an intrinsic broken power-law luminosity function can well reproduced the observed magnitude distributions.
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LIANG, EN-WEI, HOUJUN LÜ, SHUANG-XI YI, BING ZHANG, BIN-BIN ZHANG, and JIN ZHANG. "DISCERNING EMISSION COMPONENTS IN EARLY AFTERGLOW DATA AND CONSTRAINING THE INITIAL LORENTZ FACTOR OF LONG GRB FIREBALL." International Journal of Modern Physics D 20, no. 10 (September 2011): 1955–59. http://dx.doi.org/10.1142/s0218271811020007.

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We prove that both the canonical and single power-law decay X-ray afterglow lightcurves of gamma-ray bursts (GRBs) observed with the Swift X-ray telescope may be an emission component radiated by external shocks prior to the GRB trigger. Our systematical analysis on both the early optical and X-ray afterglow data also indicates that they might be from different components. The detected optical emission possibly is dominated by the afterglow of the GRB fireball. The X-ray afterglows may be detected for some GRBs, but most of the detected X-rays for most GRBs are likely dominated by the prior X-ray component. With the deceleration feature in the early optical afterglow data, we estimate the initial Lorentz factors of the GRBs and discover a tight relation of the Lorentz factor to the isotropic gamma-ray energy.
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Marongiu, M., C. Guidorzi, G. Stratta, A. Gomboc, N. Jordana-Mitjans, S. Dichiara, S. Kobayashi, D. Kopač, and C. G. Mundell. "Radio data challenge the broadband modelling of GRB 160131A afterglow." Astronomy & Astrophysics 658 (January 27, 2022): A11. http://dx.doi.org/10.1051/0004-6361/202140403.

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Context. Gamma-ray burst (GRB) afterglows originate from the interaction between the relativistic ejecta and the surrounding medium. Consequently, their properties depend on several aspects: radiation mechanisms, relativistic shock micro-physics, circumburst environment, and the structure and geometry of the relativistic jet. While the standard afterglow model accounts for the overall spectral and temporal evolution for a number of GRBs, its validity limits emerge when the data set is particularly rich and constraining, especially in the radio band. Aims. We aimed to model the afterglow of the long GRB 160131A (redshift z = 0.972), for which we collected a rich, broadband, and accurate data set, spanning from 6 × 108 Hz to 7 × 1017 Hz in frequency, and from 330 s to 160 days post-burst in time. Methods. We modelled the spectral and temporal evolution of this GRB afterglow through two approaches: (1) the adoption of empirical functions to model an optical/X-ray data set, later assessing their compatibility with the radio domain; and (2) the inclusion of the entire multi-frequency data set simultaneously through the Python package named SAGA (Software for AfterGlow Analysis), to obtain an exhaustive and self-consistent description of the micro-physics, geometry, and dynamics of the afterglow. Results. From deep broadband analysis (from radio to X-ray frequencies) of the afterglow light curves, GRB 160131A outflow shows evidence of jetted emission. Moreover, we observe dust extinction in the optical spectra, and energy injection in the optical/X-ray data. Finally, radio spectra are characterised by several peaks that could be due to either interstellar scintillation (ISS) effects or a multi-component structure. Conclusions. The inclusion of radio data in the broadband set of GRB 160131A makes a self-consistent modelling barely attainable within the standard model of GRB afterglows.
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Zhang, Bing, Peter Mészáros, and Junfeng Wang. "Some Recent Developments in γ-ray Burst Afterglow and Prompt Emission Models." Symposium - International Astronomical Union 214 (2003): 311–20. http://dx.doi.org/10.1017/s0074180900194641.

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Extensive observational campaigns of afterglow hunting have greatly enriched our understanding of the gamma-ray burst (GRB) phenomenon. Efforts have been made recently to explore some afterglow properties or signatures that will be tested by the on-going or the future observational campaigns yet come. These include the properties of GRB early afterglows in the temporal domain; the GeV-TeV afterglow signatures in the spectral domain; as well as a global view about the GRB universal structured jet configuration. These recent efforts are reviewed. Within the standard cosmological fireball model, the very model(s) responsible for the GRB prompt emission is (are) not identified. These models are critically reviewed and confronted with the current data.
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Guarini, Ersilia, Irene Tamborra, Damien Bégué, Tetyana Pitik, and Jochen Greiner. "Multi-messenger detection prospects of gamma-ray burst afterglows with optical jumps." Journal of Cosmology and Astroparticle Physics 2022, no. 06 (June 1, 2022): 034. http://dx.doi.org/10.1088/1475-7516/2022/06/034.

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Abstract Some afterglow light curves of gamma-ray bursts (GRBs) exhibit very complex temporal and spectral features, such as a sudden intensity jump about one hour after the prompt emission in the optical band. We assume that this feature is due to the late collision of two relativistic shells and investigate the corresponding high-energy neutrino emission within a multi-messenger framework, while contrasting our findings with the ones from the classic afterglow model. For a constant density circumburst medium, the total number of emitted neutrinos can increase by about an order of magnitude when an optical jump occurs with respect to the self-similar afterglow scenario. By exploring the detection prospects with the IceCube Neutrino Observatory and future radio arrays such as IceCube-Gen2 radio, RNO-G and GRAND200k, as well as the POEMMA spacecraft, we conclude that the detection of neutrinos with IceCube-Gen2 radio could enable us to constrain the fraction of GRB afterglows with a jump as well as the properties of the circumburst medium. We also investigate the neutrino signal expected for the afterglows of GRB 100621A and a GRB 130427A-like burst with an optical jump. The detection of neutrinos from GRB afterglows could be crucial to explore the yet-to-be unveiled mechanism powering the optical jumps.
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Dissertations / Theses on the topic "Afterglow"

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Updike, Adria C. "Gamma ray burst afterglow observations." Connect to this title online, 2007. http://etd.lib.clemson.edu/documents/1181668208/.

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Beier, Matthias. "Transport neutraler angeregter Spezies im Afterglow." [S.l. : s.n.], 1998. http://www.bsz-bw.de/cgi-bin/xvms.cgi?SWB10324547.

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Harrison, R. M. "Gamma-ray burst early optical afterglow modelling." Thesis, Liverpool John Moores University, 2014. http://researchonline.ljmu.ac.uk/4425/.

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We discuss the evolution of a relativistic outflow responsible for producing the emission associated with GRBs. We investigate how afterglows are produced in the inter- action between the outflow and the ambient medium. Understanding the properties of the outflow from afterglow emission can be coupled with information obtained from the prompt component to constrain the magnetisation of the outflow. We analytically and numerically evaluate the relative strength of the reverse shock emission as the out- flow propagates into either a wind or ISM -type environment. We find that previous estimates of magnetisation based on the relative strength of forward and reverse shock emission had been underestimated by up to a factor of 100. We then apply our revised magnetisation estimate to a sample of 10 GRBs and find that 5 of the 10 events can be described by the ISM model. As recent studies have indicated that the fraction of en- ergy stored in the magnetic fields are small, our findings would suggest that the ejecta is driven by thermal pressure. Finally we consider how inhomogeneities present in the outflow can lead to variations in the very early afterglow. Considering small gradi- ent in the ejecta density profile modifies the rising index of the afterglow and can be equivalent to changing the dimensionless parameter ξ by a factor of 2. Uncertainties in determining the width of the ejecta present difficulties in understanding the distribution of GRBs afterglow rising index.
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Beier, Matthias [Verfasser]. "Transport neutraler angeregter Spezies im Afterglow / Matthias Beier." Chemnitz : Universitätsbibliothek Chemnitz, 1998. http://d-nb.info/1210712156/34.

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Tam, Pak-hin. "A study of the optical afterglows of gamma-ray bursts." Thesis, Click to view the E-thesis via HKUTO, 2005. http://sunzi.lib.hku.hk/hkuto/record/B31367677.

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Hullinger, Derek. "Early afterglow evolution of x-ray flashes observed by Swift." College Park, Md. : University of Maryland, 2006. http://hdl.handle.net/1903/3374.

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Thesis (Ph. D.) -- University of Maryland, College Park, 2006.
Thesis research directed by: Physics. Title from t.p. of PDF. Includes bibliographical references. Published by UMI Dissertation Services, Ann Arbor, Mich. Also available in paper.
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Littlejohns, Owen Madoc. "Modelling the prompt and afterglow emission of gamma-ray bursts." Thesis, University of Leicester, 2013. http://hdl.handle.net/2381/27949.

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This thesis studies the broadband behaviour of GRBs by fitting a detailed spectral/temporal model to both the prompt and afterglow hard and soft X-ray emission observed by the Swift satellite. The prompt emission is decomposed into pulses which are fitted individually while the afterglow is modelled using a smoothly varying broad pulse which evolves into a power-law decay at late times. Using this model a comprehensive study of GRB 080310 is presented and followed by similar analyses of GRB 061121, GRB 080810 and GRB 081008. The optical behaviour is found to be inconsistent with the high-energy model: a spectral break between the X-ray and optical band is necessary and for many prompt pulses the self-absorption mechanism is required. The latter three bursts have optical afterglows that are shown to be inconsistent with those fitted to the X-ray regime, peaking earlier in the lower energy bands and requiring a low-energy spectral break. The prompt optical emission seen from GRB 061121 has pulse-like features which match reasonably well with contemporaneous high-energy features, but have longer durations. The same model was used to study the expected evolution of GRB properties when moved to higher redshifts. Using a sample of bright Swift GRBs, the changes in measured duration with redshift were found to be driven by a combination of time dilation, gradual loss of pulse tails and sudden loss of pulses as the flux falls below instrumental sensitivity. A realistic sample of synthetic bursts is produced which, when simulated at high redshift, are found to be significantly longer in duration that the observed high redshift GRBs. Also demonstrated is that several bright bursts seen by Swift could be detected if they occurred at a redshift > 10 encouraging the use of GRBs as probes of the early Universe.
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Zaninoni, Elena. "Gamma-ray bursts and their X-ray and optical afterglow." Doctoral thesis, Università degli studi di Padova, 2013. http://hdl.handle.net/11577/3422978.

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The aim of this PhD thesis is to study and characterize the optical and X-ray emission of the afterglows of gamma-ray bursts (GRBs). GRBs are the most powerful sources of electromagnetic radiation in the universe, with an isotropic luminosity that can reach values of $10^{54}$ erg/s. The Swift satellite, launched in November 2004, opened a new era for the study and understanding of the phenomenon of GRBs, thanks to the rapid response of its narrow FOV instruments that allows the accurate localization of most GRBs and the more complete coverage of the GRB evolution. In the first part of my PhD I was involved in a comprehensive statistical analysis of the Swift X-ray light-curves (LCs) of GRBs, carried out in a model-independent way. Our sample is composed of the X-ray LCs of more than 650 GRBs observed by Swift from December 2004 to December 2010. For 437 GRBs the statistics were good enough to allow us to extract a spectrum to convert their count-rate LCs into flux LCs. For GRBs with a known redshift, also rest-frame luminosity LCs in the 0.3-30 keV band were computed. From the fit of these LCs, we obtained the values of the temporal slopes and break times of the continuum of the X-ray emission, since the used fitting procedure automatically discards the positive fluctuations (i.e. flares). Then, we computed the total fluences and energies, those of flares and differentiating between the components of the X-ray LCs. Thanks to this large sample of LCs, we could carry out a homogeneous analysis of GRBs in a common rest frame energy band (0.3-30 keV), investigating the intrinsic time scales and energetics of the different LC phases. In addition, we studied the properties of flares superimposed to the smooth X-ray decay. GRBs are classified as long and short, depending on the duration of the prompt emission (T90>2 s and T90<2 s, respectively); our sample of GRBs allowed us to investigate the possible differencies and similarities between these two classes, for example the nature of long and short GRBs and the emission mechanisms involved. Finally, we examined the possible relation between the X-ray and gamma-ray emission and we found the existence of a universal scaling involving two parameters of the prompt emission and one of the X-ray emission: the isotropic prompt emission energy ($E_{\gamma,iso}$), the peak energy ($E_{pk}$) and the isotropic X-ray energy ($E_{X,iso}$). The main idea of the project presented above is to study all quantities that characterize the X-ray data and to look for a link between prompt and afterglow emission. During this work, we realized that the optical data were very important for our understanding, adding information to investigate the GRB emission mechanisms and to study the environment properties. Therefore, in the second part of my PhD we carried out a systematic analysis of the optical data available in literature, collecting data from all the available sources. From the collected optical data, we determine the shapes of the optical LCs. Then, we modeled the optical/X-ray spectral energy distribution (SED), we studied the SED parameter distributions and we compared the optical and X-ray LC slopes and shapes. For 20% of GRBs the difference between the optical and X-ray slopes is consistent with 0 or 1/4 within uncertainties (we do not consider here the steep decay phase), but in the majority of cases (80%) the optical and X-ray afterglows show significantly different temporal behaviors. Interestingly, we found an indication that the onset of the forward shock in the optical LCs (initial peaks or shallow phases) could be linked to the presence of the X-ray flares. Indeed when there are X-ray flares the optical LC initial peak or plateau end occurs during the steep decay, instead if there are no X-ray flares or if they occur during the plateau, the optical initial peak or plateau end takes place during the X-ray plateau. This could link the prompt emission with the optical emission. The forward shock model cannot explain all the features of the optical (e.g. bumps, late re-brightenings) and X-ray (e.g. flares, plateaus) LCs. However, the synchrotron model is a viable mechanism for GRBs afterglow emission at late times. Further to the intrinsic spectrum of the afterglow, the SED analysis allows to study the properties of the GRB environment, by quantifying the amount of absorption at optical and X-ray wavelengths. The first is due to dust while the latter is mostly due to metals. Our analysis shows that the gas-to-dust ratios of GRBs are larger than the values calculated for the Milky Way, the Large Magellanic Cloud, and the Small Magellanic Cloud assuming solar abundances.
Lo scopo di questa tesi è lo studio e la caratterizzazione dell'emissione X e ottica dei gamma-ray burst (GRB). I GRB sono la sorgente più potente di radiazione elettromagnetica dell'universo, la cui luminosità può raggiungere valori di $10^{54}$ erg/s. Il satellite Swift, lanciato nel novembre del 2004, ha aperto una nuova era per lo studio e la comprensione dei GRB, grazie alla rapida risposta dei suoi strumenti che ha permesso localizzare in modo accurato la maggior parte dei GRB e di ottenere una visione più completa della loro evoluzione. Nella prima parte del mio Dottorato sono stata coinvolta nell'analisi statistica delle curve di luce (CL) osservate nella banda energetica corrispondente ai raggi X del telescopio per i raggi X a bordo del satellite Swift. Questo studio non ha assunto alcun modello teorico per spiegare le osservazioni, ma è stato finalizzato alla raccolta di tutte le possibili informazioni osservative. Il nostro campione è composto dalle CL di più di 650 GRB osservati da Swift tra Dicembre 2004 e Dicembre 2010. Per 437 GRB, grazie alla bontà statistica dei dati, è stato possibile estrarre uno spettro per convertire le loro CL da conteggi a flusso. Per i GRB per cui è stato misurato il redshift, sono state calcolate anche le CL in luminosità nella banda energetica 0.3-30 keV nel sistema di riferimento della sorgente, in modo da approssimare la luminosità bolometrica. Dall'interpolazione dei dati delle CL, abbiamo ottenuto i valori delle pendenze temporali e dei break time, cioè dei tempi in cui la CL cambia la sua pendenza, e abbiamo caratterizzato l'andamento temporale dell'emissione duratura in banda X, escludendo le fluttuazioni (flares) che sono probabilmente dipendenti da meccanismi diversi. Per ogni GRB, sono state calcolate le densità di flusso e le energie corrispondenti all'emissione X totale, dei flares e delle diverse componenti della CL. è stata realizzata un'analisi omogenea dei GRB in una banda energetica comune (0.3-30 keV) nel sistema a riposo della sorgente. I GRB sono classificati come lunghi e corti, in base alla durata dell'emissione iniziale, detta prompt emission (T90>2 s e T90<2 s, rispettivamente); il nostro campione di GRB ci ha permesso di studiare le differenze e le somiglianze di queste queste due classi di GRB. Infine abbiamo identificato una nuova relazione tra l'emissione X e gamma trovando una legge universale che coinvolge due parametri che si riferiscono alla prompt emission e uno che si riferisce all'emissione X: l'energia totale della promp emission ($E_{\gamma,iso}$), l'energia di picco dello spettro integrato nel tempo della prompt emission ($E_{pk}$) e l'energia X ($E_{X,iso}$). L'idea principale del progetto appena discusso è lo studio di tutte le quantità che caratterizzano i dati X e la ricerca di un legame tra l'emissione prompt nei raggi gamma e quella nelle altre bande energetiche, X, ottico e radio, detta afterglow. Durante questo lavoro, ci siamo resi conto della necessità di aggiungere le informazioni che provengono dai dati ottici dei GRB, in modo da studiare in modo più dettagliato i meccanismi di emissione dei GRB e le proprietà dell'ambiente che li circonda. Quindi, nella seconda parte del mio Dottorato ho condotto un mio personale progetto di ricerca, analizzando in modo sistematico i dati ottici disponibili in letteratura. Il primo passo è stato quello di interpolare le CL ottiche, in modo da caratterizzare il loro andamento temporale. Poi abbiamo modellato le distribuzioni di energia spettrale ottica e X (SED) e abbiamo studiato le distribuzioni dei parametri ottenuti da questo studio. Infine abbiamo confrontato l'andamento temporale delle CL ottiche. Per il 20% dei GRB la differenza tra la pendenza ottica e X è consistente con i valori attesi dal modello standard per l'afterglow dei GRB, mentre nella maggior parte dei casi le CL ottiche e X mostrano un andamento temporale diverso. Inoltre, abbiamo trovato un'indicazione che l'inizio della fase di afterglow nelle CL ottiche (che corrisponde nelle CL a picchi iniziali o fasi quasi-costanti) potrebbe essere collegato alla presenza dei flare nei raggi X. Quindi, quando ci sono flares X, il picco iniziale o la fine della fase quasi-costante della curva di luce ottica avvengono durante la fase iniziale della CL X, detta steep decay, invece se non ci sono flare X o se avvengono successivamente allo steep decay, il picco iniziale o la fase quasi-costante della CL ottica si manifestano durante la fase quasi-costante della curva di luce X. Questo potrebbe legare l'emissione prompt con l'ottico. In generale, troviamo che il modello del standard per l'afterglow non può spiegare tutte le caratteristiche delle CL ottiche e X. Comunque, l'emissione di sincrotrone può essere un meccanismo plausibile per spiegare l'emissione dell'afterglow a tempi tardi. L'analisi delle SED ci ha permesso di studiare le proprietà dell'ambiente dei GRB, quantificando la quantità di assorbimento alle lunghezze d'onda ottiche e X. Il primo è dovuto alla polvere invece l'ultimo è dovuto principalmente ai metalli. La nostra analisi ha mostrato che il rapporto tra il gas e la polvere per i GRB è maggiore rispetto ai valori calcolati per la Via Lattea, la Grande Nube di Magellano e la Piccola Nube di Magellano, assumendo abbondanze solari.
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Mynampati, Venkata N. S. "Simulation of the interaction of argon/helium afterglow with ambient gasses /." Available to subscribers only, 2005. http://proquest.umi.com/pqdweb?did=1083541601&sid=4&Fmt=2&clientId=1509&RQT=309&VName=PQD.

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Valan, Vlasta. "Thermal components in the early X-ray afterglow of gamma-ray bursts." Licentiate thesis, KTH, Partikel- och astropartikelfysik, 2017. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-217103.

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Abstract:
Gamma-ray bursts (GRBs) are still puzzling scientists even 40 years after their discovery. Questions concerning the nature of the progenitors, the connection with supernovae and the origin of the high-energy emission are still lacking clear answers. Today, it is known that there are two populations of GRBs: short and long. It is also known that long GRBs are connected to supernovae (SNe). The emission observed from GRBs can be divided into two phases: the prompt emission and the afterglow. This thesis presents spectral analysis of the early X-ray afterglow of GRBs observed by the {\it Swift} satellite. For the majority of GRBs the early X-ray afterglows are well described by an absorbed power-law model. However, there exists a number of cases where this power-law component fails in fully describing the observed spectra and an additional blackbody component is needed. In the paper at the end of this thesis, a time-resolved spectral analysis of 74 GRBs observed by the X-ray telescope on board {\it Swift} is presented. Each spectrum is fitted with a power-law and a power-law plus blackbody model. The significance of the added thermal component is then assessed using Monte Carlo simulations. Six new cases of GRBs with thermal components in their spectra are presented, alongside three previously reported cases. The results show that a cocoon surrounding the jet is the most likely explanation for the thermal emission observed in the majority of GRBs. In addition, the observed narrow span in radii points to these GRBs being produced in similar environments.

QC 20171031

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Books on the topic "Afterglow"

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Adair, Cherry. Afterglow. New York: Pocket Star Books, 2012.

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Afterglow. London: Harlequin, 1986.

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Mordechai, Omer, Kassovsky Daria, Flantz Richard 1936-, and Muzeʼon Tel Aviv le-omanut, eds. Afterglow. London: August, 2002.

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Afterglow. New York: Simon & Schuster BFYR, 2014.

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Copyright Paperback Collection (Library of Congress), ed. Afterglow. New York: Bantam Books, 1997.

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Magnano, Maxi. Afterglow. Madrid]: Paripé Books, 2021.

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Parker, Genevieve. The afterglow. Stockton, Ill: Parker Homestead Press, 1994.

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Hofsess, Brooke A. Unfolding Afterglow. Rotterdam: SensePublishers, 2016. http://dx.doi.org/10.1007/978-94-6300-531-9.

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The afterglow. Birmingham [England]: Tindal Street Press, 2004.

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Koert, Dorothy. The long afterglow. Bellingham, Wash: D. Koert, 1997.

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Book chapters on the topic "Afterglow"

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Gooch, Jan W. "Afterglow." In Encyclopedic Dictionary of Polymers, 22. New York, NY: Springer New York, 2011. http://dx.doi.org/10.1007/978-1-4419-6247-8_315.

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O’Hara, Glen. "Afterglow." In Britain and the Sea, 211–36. London: Macmillan Education UK, 2010. http://dx.doi.org/10.1007/978-1-137-07312-9_10.

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Sheehan, William. "Afterglow." In A Passion for the Planets, 207–9. New York, NY: Springer New York, 2010. http://dx.doi.org/10.1007/978-1-4419-5971-3_10.

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Hofsess, Brooke A. "A Body Rising Toward the World." In Unfolding Afterglow, 1–17. Rotterdam: SensePublishers, 2016. http://dx.doi.org/10.1007/978-94-6300-531-9_1.

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Hofsess, Brooke A. "Unaccustomed Earth." In Unfolding Afterglow, 19–50. Rotterdam: SensePublishers, 2016. http://dx.doi.org/10.1007/978-94-6300-531-9_2.

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Hofsess, Brooke A. "Floating Worlds." In Unfolding Afterglow, 51–142. Rotterdam: SensePublishers, 2016. http://dx.doi.org/10.1007/978-94-6300-531-9_3.

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Hofsess, Brooke A. "These Petals Are." In Unfolding Afterglow, 143–227. Rotterdam: SensePublishers, 2016. http://dx.doi.org/10.1007/978-94-6300-531-9_4.

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Hofsess, Brooke A. "We Learn to Skate in Summer." In Unfolding Afterglow, 229–32. Rotterdam: SensePublishers, 2016. http://dx.doi.org/10.1007/978-94-6300-531-9_5.

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Hofsess, Brooke A. "Coda: The Underbody." In Unfolding Afterglow, 233–39. Rotterdam: SensePublishers, 2016. http://dx.doi.org/10.1007/978-94-6300-531-9_6.

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Hofsess, Brooke A. "Epilogue: Afterglow Burns at its Own Pace." In Unfolding Afterglow, 241–56. Rotterdam: SensePublishers, 2016. http://dx.doi.org/10.1007/978-94-6300-531-9_7.

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Conference papers on the topic "Afterglow"

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Panaitescu, A., Nobuyuki Kawai, and Shigehiro Nagataki. "Afterglow Physics." In DECIPHERING THE ANCIENT UNIVERSE WITH GAMMA-RAY BURSTS. AIP, 2010. http://dx.doi.org/10.1063/1.3509255.

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Akahoshi, Shumpei, and Mitsunori Matsushita. "Afterglow projection." In SA '18: SIGGRAPH Asia 2018. New York, NY, USA: ACM, 2018. http://dx.doi.org/10.1145/3283289.3283305.

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Sari, Re’em. "Afterglow hydrodynamics." In GAMMA-RAY BURSTS. ASCE, 1998. http://dx.doi.org/10.1063/1.55291.

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Samarian, A. A., L. Boufendi, L. Couëdel, M. Mikikian, José Tito Mendonça, David P. Resendes, and Padma K. Shukla. "Afterglow Complex Plasma." In MULTIFACETS OF DUSTRY PLASMAS: Fifth International Conference on the Physics of Dusty Plasmas. AIP, 2008. http://dx.doi.org/10.1063/1.2997268.

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Mészáros, P. "Theories of Early Afterglow." In GAMMA-RAY BURSTS IN THE SWIFT ERA: Sixteenth Maryland Astrophysics Conference. AIP, 2006. http://dx.doi.org/10.1063/1.2207895.

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Ioka, Kunihito. "Early Afterglow and Variability." In GAMMA-RAY BURSTS IN THE SWIFT ERA: Sixteenth Maryland Astrophysics Conference. AIP, 2006. http://dx.doi.org/10.1063/1.2207907.

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Oates, S. R., Yong-Feng Huang, Zi-Gao Dai, and Bing Zhang. "The Canonical Swift∕UVOT afterglow." In 2008 NANJING GAMMA-RAY BURST CONFERENCE. AIP, 2008. http://dx.doi.org/10.1063/1.3027967.

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Tagliaferri, G. "The early X‐ray afterglow." In THE MULTICOLORED LANDSCAPE OF COMPACT OBJECTS AND THEIR EXPLOSIVE ORIGINS. American Institute of Physics, 2007. http://dx.doi.org/10.1063/1.2774838.

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Galli, A., and L. Piro. "GeV afterglow emission from GRB." In THE FIRST GLAST SYMPOSIUM. AIP, 2007. http://dx.doi.org/10.1063/1.2757319.

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Frail, D. A. "A coordinated radio afterglow program." In The fifth huntsville gamma-ray burst symposium. AIP, 2000. http://dx.doi.org/10.1063/1.1361550.

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Reports on the topic "Afterglow"

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Dheandhanoo, S., and W. Fite. Construction of Flowing Afterglow Apparatus. Fort Belvoir, VA: Defense Technical Information Center, December 1990. http://dx.doi.org/10.21236/ada231062.

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Desmond, Hugh. Afterglow Radiation from Gamma Ray Bursts. Office of Scientific and Technical Information (OSTI), August 2006. http://dx.doi.org/10.2172/890774.

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Feng, Patrick L., and Gordon A. Chandler. Low-Afterglow Scintillators for High-Rate Radiation Detection. Office of Scientific and Technical Information (OSTI), September 2015. http://dx.doi.org/10.2172/1221713.

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Arrathoon, R. Flowing Afterglow Deposition for Indium Phosphide Interfacial Studies. Fort Belvoir, VA: Defense Technical Information Center, January 1986. http://dx.doi.org/10.21236/ada226672.

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Eichler, David, and Jonathan Granot. The Case for Anisotropic Afterglow Efficiency Within Gamma-Ray Burst Jets. Office of Scientific and Technical Information (OSTI), October 2005. http://dx.doi.org/10.2172/878093.

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Taylor, G. Late Time Observations of the Afterglow and Environment of GRB 030329. Office of Scientific and Technical Information (OSTI), April 2005. http://dx.doi.org/10.2172/839820.

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Granot, J. Afterglow Light Curves from Impulsive Relativistic Jets with an Unconventional Structure. Office of Scientific and Technical Information (OSTI), April 2005. http://dx.doi.org/10.2172/839882.

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Leone, Stepen R., Veronica M. Bierbaum, and G. B. Ellison. State-Resolved Dynamics of Ion-Molecule Reactions in a Flowing Afterglow. Fort Belvoir, VA: Defense Technical Information Center, November 1985. http://dx.doi.org/10.21236/ada170839.

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Granot, Jonathan, Arieh Konigl, and Tsvi Piran. Implications of the Early X-Ray Afterglow Light Curves of Swift GRBs. Office of Scientific and Technical Information (OSTI), January 2006. http://dx.doi.org/10.2172/877982.

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Granot, J. Afterglow Observations Shed New Light on the Nature of X-ray Flashes. Office of Scientific and Technical Information (OSTI), February 2005. http://dx.doi.org/10.2172/839749.

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