The puzzling afterglow of GRB 050721: a rebrightening seen in the optical but not in the X-ray

2007 ◽  
Vol 365 (1854) ◽  
pp. 1235-1240 ◽  
Author(s):  
L. Angelo Antonelli ◽  
Vincenzo Testa ◽  
Patrizia Romano ◽  
Dafne Guetta ◽  
Ken'ichi Torii ◽  
...  
Keyword(s):  
Density Profile ◽  
Gamma Ray ◽  
Matter Density ◽  
Optical Observations ◽  
Large Telescope ◽  
X Ray ◽  
Very Large Telescope ◽  
Robotic Telescope ◽  
Inner Region ◽  
First Time

We present here the analysis of the early and late multiwavelength afterglow emission, as observed by Swift a small robotic telescope and very large telescope (VLT). We compare early observations with late afterglow observations obtained with Swift and the VLT and we observe an intense rebrightening in the optical band at about 1 day after the burst, which is not present in the X-ray band. The lack of detection in X-ray of such a strong rebrightening at lower energies may be described with a variable external density profile. In such a scenario, the combined X-ray and optical observations allow us to derive that the matter density located at ∼10 17  cm from the burst is approximately a factor of 10 higher than in the inner region. This is the first time in which a rebrightening has been observed in the optical afterglow of a gamma-ray burst that is clearly absent in the X-ray afterglow.

scholarly journals An unusual transient following the short GRB 071227

2019 ◽  
Vol 489 (1) ◽  
pp. 13-27
Author(s):  
R A J Eyles ◽  
P T O’Brien ◽  
K Wiersema ◽  
R L C Starling ◽  
B P Gompertz ◽  
...  
Keyword(s):  
Gamma Ray ◽  
Thermal Emission ◽  
Chemical Properties ◽  
Major Axis ◽  
Optical Observations ◽  
X Ray ◽  
Very Large Telescope ◽  
The Galaxy ◽  
Simple Extrapolation ◽  
Emission Models

ABSTRACT We present X-ray and optical observations of the short duration gamma-ray burst GRB 071227 and its host at z = 0.381, obtained using Swift, Gemini South, and the Very Large Telescope. We identify a short-lived and moderately bright optical transient, with flux significantly in excess of that expected from a simple extrapolation of the X-ray spectrum at 0.2–0.3 d after burst. We fit the SED with afterglow models allowing for high extinction and thermal emission models that approximate a kilonova to assess the excess’ origins. While some kilonova contribution is plausible, it is not favoured due to the low temperature and high luminosity required, implying superluminal expansion and a large ejecta mass of ∼0.1 M$\odot$. We find, instead, that the transient is broadly consistent with power-law spectra with additional dust extinction of E(B − V) ∼ 0.4 mag, although a possibly thermal excess remains in the z band. We investigate the host, a spiral galaxy with an edge-on orientation, resolving its spectrum along its major axis to construct the galaxy rotation curve and analyse the star formation and chemical properties. The integrated host emission shows evidence for high extinction, consistent with the afterglow findings. The metallicity and extinction are consistent with previous studies of this host and indicate the galaxy is a typical, but dusty, late-type SGRB host.

X-ray and optical observations of the November 19, 1978 Gamma-Ray Burst source region

1981 ◽  
Vol 30 (1-4) ◽  
pp. 467-470 ◽  
Author(s):  
G. Pizzichini ◽  
J. Danziger ◽  
P. Grosb� ◽  
M. Tarenghi ◽  
T. L. Cline ◽  
...  
Keyword(s):  
Gamma Ray ◽  
Source Region ◽  
Optical Observations ◽  
Burst Source ◽  
Gamma Ray Burst ◽  
X Ray

Swift observations of gamma-ray bursts

2007 ◽  
Vol 365 (1854) ◽  
pp. 1119-1128 ◽  
Author(s):  
Neil Gehrels
Keyword(s):  
Gamma Ray ◽  
High Redshift ◽  
Gamma Ray Bursts ◽  
Optical Observations ◽  
Nearby Galaxy ◽  
X Ray ◽  
Star Forming ◽  
Star Forming Regions ◽  
Other Information ◽  
Short Grbs

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.

X-Ray and Optical Observations of the November 19, 1978 Gamma-Ray Burst Source Region

1981 ◽  
pp. 467-470
Author(s):  
G. Pizzichini ◽  
J. Danziger ◽  
P. Grosbøl ◽  
M. Tarenghi ◽  
T. L. Cline ◽  
...  
Keyword(s):  
Gamma Ray ◽  
Source Region ◽  
Optical Observations ◽  
Burst Source ◽  
Gamma Ray Burst ◽  
X Ray

scholarly journals On the origin of Supergiant Fast X-ray Transients

2018 ◽  
Vol 14 (S346) ◽  
pp. 193-196
Author(s):  
Swetlana Hubrig ◽  
Lara Sidoli ◽  
Konstantin A. Postnov ◽  
Markus Schöller ◽  
Alexander F. Kholtygin ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Neutron Star ◽  
Stellar Wind ◽  
Longitudinal Magnetic Field ◽  
High Mass ◽  
Large Telescope ◽  
X Ray ◽  
Very Large Telescope ◽  
Low X ◽  
X Ray Binaries

Abstract. A fraction of high-mass X-ray binaries are supergiant fast X-ray transients. These systems have on average low X-ray luminosities, but display short flares during which their X-ray luminosity rises by a few orders of magnitude. The leading model for the physics governing this X-ray behaviour suggests that the winds of the donor OB supergiants are magnetized. In agreement with this model, the first spectropolarimetric observations of the SFXT IGR J11215-5952 using the FORS 2 instrument at the Very Large Telescope indicate the presence of a kG longitudinal magnetic field. Based on these results, it seems possible that the key difference between supergiant fast X-ray transients and other high-mass X-ray binaries are the properties of the supergiant’s stellar wind and the physics of the wind’s interaction with the neutron star magnetosphere.

scholarly journals The Reionization of Unshocked Ejecta in SN1006

1988 ◽  
Vol 101 ◽  
pp. 59-63 ◽  
Author(s):  
A.J.S. Hamilton ◽  
R.A. Fesen
Keyword(s):  
Density Profile ◽  
Radioactive Decay ◽  
Optical Observations ◽  
Reverse Shock ◽  
X Ray ◽  
Photoionization Model ◽  
Absorption Features

AbstractThe fortuitous positioning of the Schweizer and Middleditch OB subdwarf behind SN1006 has permitted the detection and subsequent confirmation by IUE of broad (±5000 km/s) Fe II absorption features which probably arise from unshocked iron ejecta in the center of SN1006. The mass of detected Fe II, ∽0.012 M⊙, is however only 1/25 of the ∽0.3 M⊙ of Fe within ±5000 km/s predicted by carbon deflagration models. IR and optical observations exclude any appreciable iron in grains or Fe I, but high ion stages, Fe III and up, oould be present. Promising mechanisms for ionizing the unshocked iron in SN1006 include the radioactive decay of 44Ti, and photoionization by UV and X-ray emission from the reverse shock. Although the photoionization model works, insofar as it permits as much as 0.2 M⊙ of unshocked iron in the center of SN1006, agreement with the IUE data requires that the ejecta density profile be flatter, less centrally concentrated, than the W7 deflagration model of Nomoto, Thielemann, and Yokoi.

scholarly journals VERY LARGE TELESCOPE/X-SHOOTER SPECTROSCOPY OF THE CANDIDATE BLACK HOLE X-RAY BINARY MAXI J1659-152 IN OUTBURST

2012 ◽  
Vol 746 (2) ◽  
pp. L23 ◽  
Author(s):  
Ramanpreet Kaur ◽  
Lex Kaper ◽  
Lucas E. Ellerbroek ◽  
David M. Russell ◽  
Diego Altamirano ◽  
...  
Keyword(s):  
Black Hole ◽  
Large Telescope ◽  
X Ray ◽  
Very Large Telescope

X–RAY AND GAMMA-RAY OBSERVATIONS OF THE INNER REGION OF MGRO J2019+37

2010 ◽  
Vol 19 (06) ◽  
pp. 811-817
Author(s):  
V. ZABALZA ◽  
J. M. PAREDES
Keyword(s):  
Gamma Ray ◽  
X Ray ◽  
Inner Region

In order to better understand the puzzling extended TeV source MGRO J2019+37, we have performed a multiwavelength campaign from radio to X–ray covering most of its extent. Here we present an X–ray mosaic including a new observation and two archival observations performed by the X–ray observatory XMM-Newton. We have also observed the source with the gamma-ray observatory AGILE. We discuss new point-like and extended X–ray sources we have found in the field that could help elucidate the physics behind MGRO J2019+37.

OPTICAL OBSERVATIONS OF GAMMA-RAY BURSTS AT THE FIRST RUSSIAN ROBOTIC TELESCOPE MASTER

2008 ◽  
Author(s):  
N.V. TYURINA ◽  
V.M. LIPUNOV ◽  
V.G. KORNILOV ◽  
E.S. GORBOVSKOY ◽  
D.A. KUVSHINOV
Keyword(s):  
Gamma Ray ◽  
Gamma Ray Bursts ◽  
Optical Observations ◽  
Robotic Telescope

scholarly journals GRB 171205A/SN 2017iuk: A local low-luminosity gamma-ray burst

2018 ◽  
Vol 619 ◽  
pp. A66 ◽  
Author(s):  
V. D’Elia ◽  
S. Campana ◽  
A. D’Aì ◽  
M. De Pasquale ◽  
S. W. K. Emery ◽  
...  
Keyword(s):  
Gamma Ray ◽  
High Energy ◽  
Host Galaxy ◽  
Isotropic Energy ◽  
Optical Telescope ◽  
X Ray ◽  
Hydrogen Column Density ◽  
Peak Energy ◽  
First Time

Context. Gamma-ray bursts (GRBs) occurring in the local Universe constitute an interesting sub-class of the GRB family, since their luminosity is on average lower than that of their cosmological analogs. Attempts to understand in a global way this peculiar behaviour is still not possible, since the sample of low redshift GRBs is small, and the properties of individual objects are too different from each other. In addition, their closeness (and consequently high fluxes) make these sources ideal targets for extensive follow-up even with small telescopes, considering also that these GRBs are conclusively associated with supernova (SN) explosions. Aims. We aim to contribute to the study of local bursts by reporting the case of GRB 171205A. This source was discovered by Swift Burst Alert Telescope (BAT) on 2017, December 5 and soon associated with a low redshift host galaxy (z = 0.037), and an emerging SN (SN 2017iuk). Methods. We analyzed the full Swift dataset, comprising the UV-Optical Telescope (UVOT), X-ray Telescope (XRT) and BAT data. In addition, we employed the Konus-Wind high energy data as a valuable extension at γ-ray energies. Results. The photometric SN signature is clearly visible in the UVOT u, b and ν filters. The maximum emission is reached at ∼13 (rest frame) days, and the whole bump resembles that of SN 2006aj, but lower in magnitude and with a shift in time of +2 d. A prebump in the ν-band is also clearly visible, and this is the first time that such a feature is not observed achromatically in GRB–SNe. Its physical origin cannot be easily explained. The X-ray spectrum shows an intrinsic Hydrogen column density NH,int = 7.4+4.1−3.6 × 1020 cm−2, which is at the low end of the N H, int, even considering just low redshift GRBs. The spectrum also features a thermal component, which is quite common in GRBs associated with SNe, but whose origin is still a matter of debate. Finally, the isotropic energy in the γ-ray band, Eiso = 2.18+0.63−5.0 × 1049 erg, is lower than those of cosmological GRBs. Combining this value with the peak energy in the same band, Ep = 125+141−37 keV, implies that GRB 171205A is an outlier of the Amati relation, as are some other low redshift GRBs, and its emission mechanism should be different from that of canonical, farther away GRBs.

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