Broad–band spectral evolution of GRB afterglows

Masetti, N.; Pian, E.; Palazzi, E.; Amati, L.; Galama, T.J.; Vreeswijk, P. M.; Frontera, F.; Paradijs, J.A. van

doi:10.1051/aas:1999305

Cited by 7 publications

(9 citation statements)

References 12 publications

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“…Thus, this object is a cataclysmic variable -an accreting white dwarf in a binary system. Recently, Masetti et al (2010) have reached the same conclusion based on optical spectroscopic observations.…”

Section: Optical Identificationsupporting

confidence: 58%

“…However, to carry out statistical studies and to make reliable estimates of the densities of objects using the survey results, it is necessary that the completeness of the optical identifications of cataloged objects be high enough. For this purpose, several groups in the world systematically perform observations of the objects detected by the INTEGRAL observatory in an effort to establish their nature (see, e.g., Bikmaev et al 2006Bikmaev et al , 2008Burenin et al , 2009Sazonov et al 2008;Masetti et al 2007Masetti et al , 2010Tomsik et al 2008Tomsik et al , 2009). Persistent bright hard X-ray sources in our Galaxy are not that many -about 180, according to the latest catalog by Krivonos et al (2010); only 33 of them are accreting white dwarfs.…”

Section: Introductionmentioning

confidence: 99%

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IGR J16547-1916/1RXS J165443.5-191620—a new intermediate polar from the INTEGRAL galactic survey

et al. 2010

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We present the results of our optical identification of the X-ray source IGR J16547-1916 detected by the INTEGRAL observatory during a deep all-sky survey. Analysis of the spectroscopic data from the SWIFT and INTEGRAL observatories in the X-ray energy band and from the BTA (Special Astrophysical Observatory) telescope in the optical band has shown that the source is most likely an intermediate polar -an accreting white dwarf with the mass of M WD ≃ 0.85M ⊙ in a low-mass binary system. Subsequent studies of the object's rapid variability with the RTT-150 telescope have confirmed this conclusion by revealing periodic pulsations of its optical emission with a period of ≈ 550 s.

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Section: Optical Identificationsupporting

confidence: 58%

Section: Introductionmentioning

confidence: 99%

IGR J16547-1916/1RXS J165443.5-191620—a new intermediate polar from the INTEGRAL galactic survey

et al. 2010

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“…Also the values of the shock parameters ǫ e and ǫ B are reported in Table 4. In the case of GRB970228, we are not able to estimate F max (late) from the available data (Masetti et al 1999). For this GRB we report the values of these parameters for both a radiative and an adiabatic fast cooling.…”

Section: Temporal Evolution Of the Peak Energy E Pmentioning

confidence: 98%

“…For the GRBs with detected late afterglow, we also show in fig. 8, when available, the values of E p obtained from the literature (GRB970228, Masetti et al 1999 ;GRB970508, Galama et al 1998a ;GRB980329, Palazzi et al 1998 ;GRB971214, Dal Fiume et al 1999, Ramaprakash et al 1998 ). Superposed to the data is also the expected time behavior of E m for short times from GRB onset in both the radiative and adiabatic conditions of the shock.…”

Section: Temporal Evolution Of the Peak Energy E Pmentioning

confidence: 99%

Prompt and Delayed Emission Properties of Gamma‐Ray Bursts Observed with BeppoSAX

Frontera

Amati²,

Costa

et al. 2000

ASTROPHYS J SUPPL S

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We investigated the spectral evolution in the 2-700 keV energy band of Gamma-Ray Bursts (GRBs) detected by the Gamma-Ray Burst Monitor (GRBM) and localized with the Wide Field Cameras (WFCs) aboard the BeppoSAX satellite before May 1998. Most of them have been followed-up with the Narrow Field Instruments aboard the same satellite. In the light of these results we discuss open issues on the GRB phenomenon. We find that the optically thin synchrotron shock model (SSM) provides an acceptable representation of most of the timeresolved GRB spectra extending down to 2 keV, except in the initial phases of several bursts and during the whole duration of the quite strong GRB970111, where a low-energy photon depletion with respect to the thin SSM spectrum is observed. A strong and time variable low energy cut-off, consistent with absorption effect, is observed during the prompt emission of GRB980329. We find that the X-ray afterglow starts at about 50% of the GRB duration, and that its fluence, as computed from the WFC light curve, is consistent with the decay law found from the afterglow NFI observations. We also investigate the hydrodynamical evolution of the GRB in our sample and their associated afterglow, when it was detected. We find that the photon index of the latest spectrum of the GRB prompt emission is correlated with the index of the afterglow fading law, when available, as expected on the basis of an external shock of a relativistic fireball. We also find that for most of the GRBs in our sample the late emission is consistent with a slow cooling of the shock. Adiabatic shocks appear more likely than radiative shocks. Parameters of the shocks at earliest times have been derived.

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“…The detection of their longerwavelength counterparts (Costa et al 1997;van Paradijs et al 1997;Guarnieri et al 1997;Frail et al 1997), has made it clear that multiwavelength studies of these phenomena are critical in order to constrain the parameters of the emission models and of the circumburst medium (see e.g. Galama et al 1998a;Palazzi et al 1998;Masetti et al 1999).…”

Section: Introductionmentioning

confidence: 99%

Physics of the GRB 030328 afterglow and its environment

Maiorano

Masetti

Palazzi

et al. 2006

A&A

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Aims. To investigate the physical nature of the afterglow emission. We report on the photometric, spectroscopic and polarimetric observations of the optical afterglow of Gamma-Ray Burst (GRB) 030328 detected by HETE-2. Methods. Photometric, spectroscopic and polarimetric monitoring of the optical afterglow. Results. Photometry, collected at 7 different telescopes, shows that a smoothly broken powerlaw decay, with indices α 1 = 0.76 ± 0.03, α 2 = 1.50 ± 0.07 and a break at t b = 0.48 ± 0.03 days after the GRB, provides the best fit of the optical afterglow decline. This shape is interpreted as due to collimated emission, for which we determine a jet opening angle θ jet ∼ 3.• 2. An achromatic bump starting around ∼0.2 d after the GRB is possibly marginally detected in the optical light curves. Optical spectroscopy shows the presence of two rest-frame ultraviolet metal absorption systems at z = 1.5216 ± 0.0006 and at z = 1.295 ± 0.001, the former likely associated with the GRB host galaxy. Analysis of the absorption lines at z = 1.5216 suggests that the host of this GRB may be a Damped Lyman-α Absorber. The optical V-band afterglow appears polarized, with P = (2.4 ± 0.6)% and θ = 170• ± 7• , suggesting an asymmetric blastwave expansion. An X-ray-to-optical spectral flux distribution of the GRB 030328 afterglow was obtained at 0.78 days after the GRB and fitted using a broken powerlaw, with an optical spectral slope β opt = 0.47 ± 0.15, and an X-ray slope β X = 1.0 ± 0.2. Conclusions. The discussion of the results in the context of the "fireball model" shows that the preferred scenario for this afterglow is collimated structured jet with fixed opening angle in a homogeneous medium. Observatory (Australia), the 1m Sampurnanand telescope at the ARIES observatory (India), and the 1 m NOFS telescope of USNO in Flagstaff (USA).

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Broad–band spectral evolution of GRB afterglows

Cited by 7 publications

References 12 publications

IGR J16547-1916/1RXS J165443.5-191620—a new intermediate polar from the INTEGRAL galactic survey

IGR J16547-1916/1RXS J165443.5-191620—a new intermediate polar from the INTEGRAL galactic survey

Prompt and Delayed Emission Properties of Gamma‐Ray Bursts Observed with BeppoSAX

Physics of the GRB 030328 afterglow and its environment

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