Recombination Coefficient of Heavy Elements Using Photoionization Modeling

Goshu, Belay Sitotaw

doi:10.11648/j.ajaa.20170504.11

Cited by 1 publication

(1 citation statement)

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“…3.4. In the above we have assumed the recombination rate from Goshu (2017) for N v and that this is the same for N v to N viii. If the recombination rate is an order of magnitude lower or higher this would then yield electron densities of 2 × 10 5 cm −3 and 2 × 10 3 cm −3 instead, respectively.…”

Section: Highly-ionized Gas From Recombinationmentioning

confidence: 99%

Highly ionized metals as probes of the circumburst gas in the natal regions of gamma-ray bursts

Heintz

Watson

Jakobsson

et al. 2018

Monthly Notices of the Royal Astronomical Society

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We present here a survey of high-ionization absorption lines in the afterglow spectra of longduration gamma-ray bursts (GRBs) obtained with the VLT/X-shooter spectrograph. Our main goal is to investigate the circumburst medium in the natal regions of GRBs. Our primary focus is on the N v λλ 1238,1242 line transitions, but we also discuss other high-ionization lines such as O vi, C iv and Si iv. We find no correlation between the column density of N v and the neutral gas properties such as metallicity, H i column density and dust depletion, however the relative velocity of N v, typically a blueshift with respect to the neutral gas, is found to be correlated with the column density of H i. This may be explained if the N v gas is part of an H ii region hosting the GRB, where the region's expansion is confined by dense, neutral gas in the GRB's host galaxy. We find tentative evidence (at 2σ significance) that the X-ray derived column density, N H,X , may be correlated with the column density of N v, which would indicate that both measurements are sensitive to the column density of the gas located in the vicinity of the GRB. We investigate the scenario where N v (and also O vi) is produced by recombination after the corresponding atoms have been stripped entirely of their electrons by the initial prompt emission, in contrast to previous models where highly-ionized gas is produced by photoionization from the GRB afterglow.

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Section: Highly-ionized Gas From Recombinationmentioning

confidence: 99%