XMM-Newton and INTEGRAL observations of the bright GRB 230307A : vanishing of the local absorption and limits on the dust in the Magellanic Bridge
0
Citation
0
Reference
10
Related Paper
Abstract:
230307A is the second brightest gamma ray burst detected in more than 50 years of observations and is located in the direction of the Magellanic Bridge. Despite its long duration, it is most likely the result of the compact merger of a binary ejected from a galaxy in the local universe (redshift z=0.065). Our XMM-Newton observation of its afterglow at 4.5 days shows a power-law spectrum with photon index $\Gamma =1.73 \pm0.10$, unabsorbed flux $F_{0.3-10\,\rm keV}=(8.8\pm0.5)\times 10^{-14}$ erg cm$^{-2}$ s$^{-1}$ and no absorption in excess of that produced in our Galaxy and in the Magellanic Bridge. We derive a limit of $N_{\rm H}^{\rm HOST} < 5\times 10^{20}$ cm$^{-2}$ on the absorption at the GRB redshift, which is a factor $\sim\,$5 below the value measured during the prompt phase. We searched for the presence of dust scattering rings with negative results and set an upper limit of the order of $A_V<0.05$ on the absorption from dust in the Magellanic Bridge.Keywords:
Large Magellanic Cloud
Extinction (optical mineralogy)
The successful launch and operation of NASA’s Swift Gamma‐Ray Burst Explorer open a new era for a multi‐wavelength study of the very early afterglow phase of gamma‐ray bursts (GRBs). GRB early afterglow information is very essential to explore the unknown physical composition of GRB jets, the link between the prompt γ‐ray emission and the afterglow emission, the GRB central engine activity, as well as the immediate GRB environment. Here I review some of the recent theoretical efforts to address these problems and describe how the latest Swift data give answers to these outstanding questions.
Swift
Cite
Citations (3)
We report on follow-up observations of 20 short-duration gamma-ray bursts (T90 < 2s) performed in g′r′i′z′JHKs with the Gamma-Ray Burst Optical Near-Infrared Detector (GROND) between mid-2007 and the end of 2010. This is the most homogeneous and comprehensive data set on GRB afterglow observations of short bursts. In three cases, GROND was on target within less than 10 min after the trigger, leading to the discovery of the afterglow of GRB 081226A and its faint underlying host galaxy. In addition, GROND was able to image the optical afterglow and follow the light curve evolution in five further cases: GRBs 090305, 090426, 090510, 090927, and 100117A. Three of the aforementioned six bursts with optical light curves show a break: GRBs 090426 and 090510 as well as GRB 090305. For GRB 090927, no break is seen in the optical/X-ray light curve until about 150 ks/600 ks after the burst. A decay slope of the optical afterglow of GRB 100117A could be measured. Using these data supplemented by about ten events taken from the literature, we compare the jet half-opening angles of long and short bursts. We find a tentative evidence that short bursts have wider opening angles than long bursts. However, the statistics are still very poor and follow-up observations of these events are therefore very important to gain as much observational data as possible.
Cite
Citations (1)
We present a set of seventeen Gamma-Ray Bursts (GRBs) with known redshifts and X-ray afterglow emission. We apply cosmological corrections in order to compare their fluxes normalized at a redshift of 1. Two classes of GRB can be defined using their X-ray afterglow light curves. We show that the brightest afterglows seem to decay faster than the dimmer ones. We also point out evidence for a possible flux limit of the X-ray afterglow depending on the time elapsed since the burst. We try to interpret these observations in the framework of the canonical fireball model of GRB afterglow emission.
Cite
Citations (22)
Gamma-ray burst (GRB) emission is believed to originate in highly relativistic fireballs. Currently, only lower limits were securely set to the initial fireball Lorentz factor Gamma_0. We aim to provide a direct measure of Gamma_0. The early-time afterglow light curve carries information about Gamma_0, which determines the time of the afterglow peak. We have obtained early observations of the near-infrared afterglows of GRB 060418 and GRB 060607A with the REM robotic telescope. For both events, the afterglow peak could be clearly singled out, allowing a firm determination of the fireball Lorentz of Gamma_0 ~ 400, fully confirming the highly relativistic nature of GRB fireballs. The deceleration radius was inferred to be R_dec ~ 10^17 cm. This is much larger than the internal shocks radius (believed to power the prompt emission), thus providing further evidence for a different origin of the prompt and afterglow stages of the GRB.
Cite
Citations (0)
GRBs 050223 and 050911 are examples of Swift bursts with two of the faintest X‐ray afterglows at (relatively) early times. While a faint, fading X‐ray afterglow was located for GRB 050223, GRB 050911 was not detected, making any X‐ray afterglow extremely faint. The faintness of the afterglow of GRB 050223 could be explained by a large opening or viewing angle, or by the burst being at high redshift. The non‐detection of GRB 050911 may indicate the burst occurred in a low‐density environment, or, alternatively, was due to a compact object merger, in spite of the apparent long duration of the burst.
Swift
Cite
Citations (0)
The rapid follow‐up of gamma‐ray burst (GRB) afterglows made possible by the multi‐wavelength satellite Swift, launched in November 2004, has put under a microscope the GRB early post‐burst behavior, This is leading to a significant reappraisal and expansion of the standard view of the GRB early afterglow behavior, and its connection to the prompt gamma‐ray emission. In addition to opening up the previously poorly known behavior on minutes to hours timescales, two other new pieces in the GRB puzzle being filled in are the the discovery and follow‐up of short GRB afterglows, and the opening up of the z ≳ 6 redshift range. We review some of the current theoretical interpretations of these new phenomena.
Swift
Cite
Citations (1)
We extend the standard fireball model, widely used to interpret gamma-ray burst (GRB) afterglow light curves, to include energy injections and apply the model to the afterglow light curves of GRB 990510, GRB 000301C, and GRB 010222. We show that discrete energy injections can cause temporal variations in the optical light curves, and we present fits to the light curves of GRB 000301C as an example. A continuous injection may be required to interpret other bursts, such as GRB 010222. The extended model accounts reasonably well for the observations in all bands ranging from X-rays to radio wavelengths. In some cases the radio light curves indicate that additional model ingredients may be needed.
Cite
Citations (30)
When does a GRB stop and its afterglow begin? A GRB may be defined as emission by internal shocks and its afterglow as emission by an external shock, but it is necessary to distinguish them observationally. With these definitions irregularly varying emission (at any frequency) must be the GRB, but smoothly varying intensity is usually afterglow. The GRB itself and its afterglow may overlap in time and in frequency, and distinguishing them will, in general, require detailed modeling.
Cite
Citations (1)
We present our multi‐band optical afterglow observations of the long duration GRB 021004 and GRB 030226 in combination with other published data to study the nature of the bursts. Optical afterglow light‐curves of both the GRBs exhibit signatures of collimated outflow. Observed superimposed variability in the case of GRB 021004, in the form of bumps and wiggles, suggest density fluctuations in the ambient medium. The derived temporal and spectral flux decay indices of GRB 030226 afterglow show an inconsistency with the theoretically predicted values.
Collimated light
Outflow
Cite
Citations (0)
Gamma-ray bursts (GRBs), which are bright flashes of gamma rays from extragalactic sources followed by fading afterglow emission, are associated with stellar core collapse events. We report the detection of very-high-energy (VHE) gamma rays from the afterglow of GRB 190829A, between 4 and 56 hours after the trigger, using the High Energy Stereoscopic System (H.E.S.S.). The low luminosity and redshift of GRB 190829A reduce both internal and external absorption, allowing determination of its intrinsic energy spectrum. Between energies of 0.18 and 3.3 tera-electron volts, this spectrum is described by a power law with photon index of 2.07 $\pm$ 0.09, similar to the x-ray spectrum. The x-ray and VHE gamma-ray light curves also show similar decay profiles. These similar characteristics in the x-ray and gamma-ray bands challenge GRB afterglow emission scenarios.
Spectral index
Cite
Citations (135)