Optical/UV afterglows: Swift UVOT overview

Author(s):  
Keith O Mason ◽  
Patricia Boyd ◽  
Mathew Page ◽  
Shashi Pandey ◽  
Pete Roming ◽  
...  

The ultraviolet and optical telescope (UVOT) on Swift provides coverage of gamma-ray bursts and their afterglows in the 170–650 nm band, yielding multiwavelength data of considerable diagnostic power in conjunction with the Swift X-ray Telescope. The results from the first eighteen months of operation show a broad range of afterglow behaviour, with considerably more complexity in many bursts than would be expected from the simple fireball model for the explosion. We briefly illustrate the capabilities of UVOT for measuring the evolution of nearby supernovae by reference to the observations of GRB 060218, and discuss the peculiar case of GRB 060614, which apparently resides in a nearby galaxy but which did not show the expected supernova feature in its light curve due to radioactive nickel decay. We discuss how the combination of X-ray and UV/optical spectral data can be used to investigate the environment of GRB host galaxies.

Author(s):  
Tsvi Piran ◽  
Yi-Zhong Fan

Afterglow observations in the pre-Swift era confirmed to a large extend the relativistic blast wave model for gamma-ray bursts (GRBs). Together with the observations of properties of host galaxies and the association with (type Ic) SNe, this has led to the generally accepted collapsar origin of long GRBs. However, most of the afterglow data was collected hours after the burst. The X-ray telescope and the UV/optical telescope onboard Swift are able to slew to the direction of a burst in real time and record the early broadband afterglow light curves. These observations, and in particular the X-ray observations, resulted in many surprises. While we have anticipated a smooth transition from the prompt emission to the afterglow, many observed that early light curves are drastically different. We review here how these observations are changing our understanding of GRBs.


Author(s):  
Neil Gehrels

Since its launch on 20 November 2004, the Swift mission has been detecting approximately 100 gamma-ray bursts (GRBs) each year, and immediately (within approx. 90 s) starting simultaneous X-ray and UV/optical observations of the afterglow. It has already collected an impressive database, including prompt emission to higher sensitivities than BATSE, uniform monitoring of afterglows and a rapid follow-up by other observatories notified through the GCN. Advances in our understanding of short GRBs have been spectacular. The detection of X-ray afterglows has led to accurate localizations and the conclusion that short GRBs can occur in non-star-forming galaxies or regions, whereas long GRBs are strongly concentrated within the star-forming regions. This is consistent with the NS merger model. Swift has greatly increased the redshift range of GRB detection. The highest redshift GRBs, at z ∼5–6, are approaching the era of reionization. Ground-based deep optical spectroscopy of high redshift bursts is giving metallicity measurements and other information on the source environment to a much greater distance than other techniques. The localization of GRB 060218 to a nearby galaxy, and the association with SN 2006aj, added a valuable member to the class of GRBs with detected supernova.


2011 ◽  
Vol 7 (S279) ◽  
pp. 433-446

Measuring cosmological parameters with GRBs: status and perspectivesNew interpretation of the Amati relationThe SED Machine - a dedicated transient spectrographPTF10iue - evidence for an internal engine in a unique Type Ic SNDirect evidence for the collapsar model of long gamma-ray burstsOn pair instability supernovae and gamma-ray burstsPan-STARRS1 observations of ultraluminous SNeThe influence of rotation on the critical neutrino luminosity in core-collapse supernovaeGeneral relativistic magnetospheres of slowly rotating and oscillating neutron starsHost galaxies of short GRBsGRB 100418A: a bridge between GRB-associated hypernovae and SNeTwo super-luminous SNe at z ~ 1.5 from the SNLSProspects for very-high-energy gamma-ray bursts with the Cherenkov Telescope ArrayThe dynamics and radiation of relativistic flows from massive starsThe search for light echoes from the supernova explosion of 1181 ADThe proto-magnetar model for gamma-ray burstsStellar black holes at the dawn of the universeMAXI J0158-744: the discovery of a supersoft X-ray transientWide-band spectra of magnetar burst emissionDust formation and evolution in envelope-stripped core-collapse supernovaeThe host galaxies of dark gamma-ray burstsKeck observations of 150 GRB host galaxiesSearch for properties of GRBs at large redshiftThe early emission from SNeSpectral properties of SN shock breakoutMAXI observation of GRBs and short X-ray transientsA three-dimensional view of SN 1987A using light echo spectroscopyX-ray study of the southern extension of the SNR Puppis AAll-sky survey of short X-ray transients by MAXI GSCDevelopment of the CALET gamma-ray burst monitor (CGBM)


2012 ◽  
Vol 539 ◽  
pp. A3 ◽  
Author(s):  
M. G. Bernardini ◽  
R. Margutti ◽  
J. Mao ◽  
E. Zaninoni ◽  
G. Chincarini

2019 ◽  
Vol 487 (4) ◽  
pp. 5010-5018 ◽  
Author(s):  
L C Strang ◽  
A Melatos

Abstract Many short gamma-ray bursts (sGRBs) exhibit a prolonged plateau in the X-ray light curve following the main burst. It is shown that an X-ray plateau at the observed luminosity emerges naturally from a plerion-like model of the sGRB remnant, in which the magnetized, relativistic wind of a millisecond magnetar injects shock-accelerated electrons into a cavity confined by the sGRB blast wave. A geometry-dependent fraction of the plerionic radiation is also intercepted and reprocessed by the optically thick merger ejecta. The relative contributions of the plerion and ejecta to the composite X-ray light curve are estimated approximately with the aid of established ejecta models. The plerionic component of the electron energy spectrum is evolved under the action of time-dependent, power-law injection and adiabatic and synchrotron cooling in order to calculate the X-ray light curve analytically. The model yields an anticorrelation between the luminosity and duration of the plateau as well as a sudden cut-off in the X-ray flux, if the decelerating magnetar collapses to form a black hole. Both features are broadly consistent with the data and can be related to the surface magnetic field of the magnetar and its angular velocity at birth. The analogy with core-collapse supernova remnants is discussed briefly.


2013 ◽  
Vol 431 (4) ◽  
pp. 3159-3176 ◽  
Author(s):  
R. L. C. Starling ◽  
R. Willingale ◽  
N. R. Tanvir ◽  
A. E. Scott ◽  
K. Wiersema ◽  
...  

2008 ◽  
Vol 17 (09) ◽  
pp. 1311-1317
Author(s):  
NEIL GEHRELS

The Swift mission, launched on 20 November 2004, is detecting ~ 100 gamma-ray bursts (GRBs) each year, and immediately (within ~ 90 s) starting X-ray and UV/optical observations of the afterglow. It has already collected an impressive database including prompt emission to higher sensitivities than BATSE, uniform monitoring of afterglows, and rapid follow-up by other observatories notified through the Gamma-ray bursts Coordinates Network (GCN). The X-ray afterglows have been found to have complex temporal shapes including tails emission from the prompt phase and bright flares. X-ray and optical afterglow detections from short bursts have led to accurate localizations. It is found that they can occur in non-star forming galaxies or regions, whereas long GRBs are strongly concentrated within star forming regions. This is consistent with the NS merger model. Swift has greatly increased the redshift range of GRB detection. The highest redshift GRBs, at z ~ 5-6, are approaching the era of reionization. Ground-based deep optical spectroscopy of high redshift bursts is giving metallicity measurements and other information on the source environment to much greater distance than other techniques. The localization of GRB 060218 in a nearby galaxy, and association with SN 2006aj, added a valuable member to the class of GRBs with detected supernova. The prospects for future progress are excellent given the > 10 year orbital lifetime of the Swift satellite.


2018 ◽  
Vol 27 (10) ◽  
pp. 1844012
Author(s):  
Elena Mazaeva ◽  
Alexei Pozanenko ◽  
Pavel Minaev

We discuss the inhomogeneous behavior of gamma-ray burst afterglow light curves in optic. We use well-sampled light curves based on mostly our own observations to find and identify deviations (inhomogeneities) from broken power law. By the inhomogeneous behavior we mean flashes, bumps, slow deviations from power law (wiggles) in a light curve. In particular we report parameters of broken power law, describe phenomenology, compare optical light curves with X-ray ones and classify the inhomogeneities. We show that the duration of the inhomogeneities correlates with their peak time relative to gamma-ray burst (GRB) trigger and the correlation is the same for all types of inhomogeneities.


2021 ◽  
Vol 366 (4) ◽  
Author(s):  
Zhi-Ying Liu ◽  
Fu-Wen Zhang ◽  
Si-Yuan Zhu

2020 ◽  
Vol 499 (4) ◽  
pp. 5986-5992
Author(s):  
Nikhil Sarin ◽  
Paul D Lasky ◽  
Gregory Ashton

ABSTRACT 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 arbitrary braking index. Combining this with a model for the tail of the prompt emission, we show that our model can better explain the data than millisecond-magnetar models without radiative losses or those that invoke spin-down solely through vacuum dipole radiation. We find that our model predicts a subset of X-ray flares seen in some gamma-ray bursts. We can further explain the diversity of X-ray plateaus by altering the radiative efficiency and measure the braking index of newly born millisecond magnetars. We measure the braking index of GRB061121 as $n=4.85^{+0.11}_{-0.15}$ suggesting the millisecond-magnetar born in this gamma-ray burst spins down predominantly through gravitational-wave emission.


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