Soft X-ray observation of the prompt emission of GRB 100418A

Imatani, R.; Tomida, H.; Nakahira, S.; Kimura, Masashi; Sakamoto, T.; Arimoto, M.; Morooka, Y.; Yonetoku, Daisuke; Kawai, N.; Tsunemi, H.

doi:10.1093/pasj/psv075

Cited by 2 publications

(2 citation statements)

References 40 publications

(53 reference statements)

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“…On the other hand, Kagawa et al (2015) reported that the exponential temporal decay model was able to fit some extended emissions with an e-folding time of 50 -100 seconds. Similar studies on the exponential decay has been performed for early X-ray emissions of long GRBs (LGRBs) (e.g., Willingale et al 2007;Sakamoto et al 2007;Imatani et al 2016). Therefore, in this paper, we report a systematic study on phenomenological modeling for the extended emission light curves of SGRBs by adopting the exponential and power-law decay models, and a comparison of both models for discussing which model is suitable for describing the observed light curves of the extended mission.…”

Section: Introductionmentioning

confidence: 61%

Exponentially Decaying Extended Emissions Following Short Gamma-Ray Bursts with a Possible Luminosity–E-folding Time Correlation

Kagawa¹,

Yonetoku²,

Sawano³

et al. 2019

ApJ

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The origin of extended emissions following prompt emissions of short gamma-ray bursts (SGRBs) is in mystery. The long-term activity of the extended emission is responsible for promising electromagnetic counterparts to gravitational waves and, so that it may be a key to uncovering the progenitor of SGRBs. We investigate the early X-ray light curves of 26 SGRBs with known redshifts observed with the X-Ray Telescope aboard the Neil Gehrels Swift Observatory (Swift). We find that the exponential temporal decay model is able to describe the extended emissions comprehensively with a rest-frame e-folding time of 20 -200 seconds. We also estimate the isotropic equivalent energies of the extended emission with the exponential decay model and of the prompt emission, compared with those of the prompt emission. Then, it is revealed that the extended emission is 0 -3 orders of magnitude less powerful than the prompt emission. We find a strong correlation between the expected maximum luminosity and e-folding time which can be described by a power-law with an index of −3.3 and whose chance probability of 8.2 × 10 −6 if there is no observation bias of Swift. The exponential temporal decay may be interpreted to come from the spin-down time scale of the rotation energy of a highly magnetized neutron star, and/or fallback accretion onto a disk surrounding a black hole with an exponentially decaying magnetic flux by magnetic reconnection.

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Section: Introductionmentioning

confidence: 61%

Exponentially Decaying Extended Emissions Following Short Gamma-Ray Bursts with a Possible Luminosity–E-folding Time Correlation

Kagawa¹,

Yonetoku²,

Sawano³

et al. 2019

ApJ

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“…This identifies GRB 100418A as a long GRB according to the classical division (Kouveliotou et al 1993), but also as a prototypical intermediate burst, according to the definition of Horváth et al (2010), with a probability of 0.998 of belonging to this class. The prompt emission was also detected in the soft X-ray band by MAXI SSC (Imatani et al 2016).…”

Section: Observationsmentioning

confidence: 90%

The luminous host galaxy, faint supernova and rapid afterglow rebrightening of GRB 100418A

Postigo

Thöne

Bensch

et al. 2018

A&A

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Context. Long gamma-ray bursts (GRBs) give us the chance to study both their extreme physics and the star-forming galaxies in which they form. Aims. GRB 100418A, at a redshift of z = 0.6239, had a bright optical and radio afterglow, and a luminous star-forming host galaxy. This allowed us to study the radiation of the explosion as well as the interstellar medium of the host both in absorption and emission. Methods. We collected photometric data from radio to X-ray wavelengths to study the evolution of the afterglow and the contribution of a possible supernova (SN) and three X-shooter spectra obtained during the first 60 hr.Results. The light curve shows a very fast optical rebrightening, with an amplitude of ∼ 3 magnitudes, starting 2.4 hr after the GRB onset. This cannot be explained by a standard external shock model and requires other contributions, such as late central-engine activity. Two weeks after the burst we detect an excess in the light curve consistent with a SN with peak absolute magnitude M V = −18.5 mag, among the faintest GRB-SNe detected to date. The host galaxy shows two components in emission, with velocities differing by 130 km s −1 , but otherwise having similar properties. While some absorption and emission components coincide, the absorbing gas spans much higher velocities, indicating the presence of gas beyond the star-forming regions. The host has a star formation rate of SFR = 12.2 M ⊙ yr −1 , a metallicity of 12 + log(O/H) = 8.55, and a mass of 1.6 × 10 9 M ⊙ . Conclusions. GRB 100418A is a member of a class of afterglow light curves which show a steep rebrightening in the optical during the first day, which cannot be explained by traditional models. Its very faint associated SN shows that GRB-SNe can have a larger dispersion in luminosities than previously seen. Furthermore, we have obtained a complete view of the host of GRB 100418A owing to its spectrum, which contains a remarkable number of both emission and absorption lines.

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Soft X-ray observation of the prompt emission of GRB 100418A

Cited by 2 publications

References 40 publications

Exponentially Decaying Extended Emissions Following Short Gamma-Ray Bursts with a Possible Luminosity–E-folding Time Correlation

Exponentially Decaying Extended Emissions Following Short Gamma-Ray Bursts with a Possible Luminosity–E-folding Time Correlation

The luminous host galaxy, faint supernova and rapid afterglow rebrightening of GRB 100418A

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