Author:
Publisher:
ISBN:
Category :
Languages : en
Pages : 17
Book Description
We review the theoretical framework of both line and continuum spectra formation in gamma ray bursts. These include the cyclotron features at 10's of keV, redshifted annihilation features at (approximately)400 keV, as well as other potentially detectable nuclear transition lines, atomic x-ray lines, proton cyclotron lines and plasma oscillation lines. By combining the parameters derived from line and continuum modeling we can try to reconstruct the location, geometry and physical conditions of the burst emission region, thereby constraining and discriminating the astrophysical models. Hence spectroscopy with current and future generations of detectors should provide powerful diagnostic tools for gamma ray bursters. 48 refs., 10 figs., 4 tabs.
Line and Continuum Spectroscopy as Diagnostic Tools for Gamma Ray Bursts
Author:
Publisher:
ISBN:
Category :
Languages : en
Pages : 17
Book Description
We review the theoretical framework of both line and continuum spectra formation in gamma ray bursts. These include the cyclotron features at 10's of keV, redshifted annihilation features at (approximately)400 keV, as well as other potentially detectable nuclear transition lines, atomic x-ray lines, proton cyclotron lines and plasma oscillation lines. By combining the parameters derived from line and continuum modeling we can try to reconstruct the location, geometry and physical conditions of the burst emission region, thereby constraining and discriminating the astrophysical models. Hence spectroscopy with current and future generations of detectors should provide powerful diagnostic tools for gamma ray bursters. 48 refs., 10 figs., 4 tabs.
Publisher:
ISBN:
Category :
Languages : en
Pages : 17
Book Description
We review the theoretical framework of both line and continuum spectra formation in gamma ray bursts. These include the cyclotron features at 10's of keV, redshifted annihilation features at (approximately)400 keV, as well as other potentially detectable nuclear transition lines, atomic x-ray lines, proton cyclotron lines and plasma oscillation lines. By combining the parameters derived from line and continuum modeling we can try to reconstruct the location, geometry and physical conditions of the burst emission region, thereby constraining and discriminating the astrophysical models. Hence spectroscopy with current and future generations of detectors should provide powerful diagnostic tools for gamma ray bursters. 48 refs., 10 figs., 4 tabs.
Scientific and Technical Aerospace Reports
Author:
Publisher:
ISBN:
Category : Aeronautics
Languages : en
Pages : 456
Book Description
Lists citations with abstracts for aerospace related reports obtained from world wide sources and announces documents that have recently been entered into the NASA Scientific and Technical Information Database.
Publisher:
ISBN:
Category : Aeronautics
Languages : en
Pages : 456
Book Description
Lists citations with abstracts for aerospace related reports obtained from world wide sources and announces documents that have recently been entered into the NASA Scientific and Technical Information Database.
Gamma-Ray Line Astrophysics
Author: Philippe Durouchoux
Publisher: AIP Conference Proceedings Ser
ISBN:
Category : Nature
Languages : en
Pages : 552
Book Description
Publisher: AIP Conference Proceedings Ser
ISBN:
Category : Nature
Languages : en
Pages : 552
Book Description
A Study of the Temporal and Spectral Characteristics of Gamma Ray Bursts
Author: Jay Preston Norris
Publisher:
ISBN:
Category : Gamma ray astronomy
Languages : en
Pages : 570
Book Description
Publisher:
ISBN:
Category : Gamma ray astronomy
Languages : en
Pages : 570
Book Description
Energy Research Abstracts
Gamma-ray Spectroscopy: with Particular Reference to Detector and Computer Evaluation Techniques
Author: Pál Quittner
Publisher:
ISBN:
Category : Science
Languages : en
Pages : 120
Book Description
Publisher:
ISBN:
Category : Science
Languages : en
Pages : 120
Book Description
Analysis of Gamma Ray Burst Spectra with Cyclotron Lines
Author:
Publisher:
ISBN:
Category :
Languages : en
Pages : 8
Book Description
Motivated by the recent developments in the cyclotron resonance upscattering of soft photons or CUSP model of Gamma Ray Burst (GRB) continuum spectra, we revisit a select database of GRBs with credible cyclotron absorption features. We measure the break energy of the continuum, the slope below the break and deduce the soft photon energy or the electron beam Lorentz factor cutoff. We study the correlation (or lack of) between various parameters in the context of the CUSP model. One surprise result is that there appears to be marginal correlation between the break energy and the spectral index below the break. 20 refs., 8 figs., 2 tabs.
Publisher:
ISBN:
Category :
Languages : en
Pages : 8
Book Description
Motivated by the recent developments in the cyclotron resonance upscattering of soft photons or CUSP model of Gamma Ray Burst (GRB) continuum spectra, we revisit a select database of GRBs with credible cyclotron absorption features. We measure the break energy of the continuum, the slope below the break and deduce the soft photon energy or the electron beam Lorentz factor cutoff. We study the correlation (or lack of) between various parameters in the context of the CUSP model. One surprise result is that there appears to be marginal correlation between the break energy and the spectral index below the break. 20 refs., 8 figs., 2 tabs.
Problems in the Analysis of Gamma-ray Burst Spectra
Author:
Publisher:
ISBN:
Category :
Languages : en
Pages :
Book Description
Spectral measurements by the Solar Maximum Mission have been used to confirm the cyclotron lines in gamma-ray bursts reported from the Konus experiment. We present ISEE-3 data for the same burst (GB800419) during the same period of time which show no line. We discuss various problems in the analysis of scintillator spectra and point out that unfolded spectra are not necessarily unique and that the position of a data point in a deconvolved spectrum may vary depending on the assumed overall shape of the spectrum. As a result, if the analysis assumes a soft spectrum (such as optically thin thermal bremsstrahlung) an absorption feature might appear, whereas a harder spectrum (such as a Comptonized blackbody) would not require the feature. Since the continuum shape probably changes during the duration of a typical burst, the nonuniqueness of the spectral unfolding, combined with the assumption that the continuum is optically thin thermal bremsstrahlung, could give rise to spurious absorption features which vary on a time scale of seconds. Despite these problems, there is still some evidence for narrow spectral lines in the range 45 to 65 keV but not for the broad lines reported from the Konus experiment. Unfortunately, the range 45 to 65 keV is the most difficult spectral region to unfold.
Publisher:
ISBN:
Category :
Languages : en
Pages :
Book Description
Spectral measurements by the Solar Maximum Mission have been used to confirm the cyclotron lines in gamma-ray bursts reported from the Konus experiment. We present ISEE-3 data for the same burst (GB800419) during the same period of time which show no line. We discuss various problems in the analysis of scintillator spectra and point out that unfolded spectra are not necessarily unique and that the position of a data point in a deconvolved spectrum may vary depending on the assumed overall shape of the spectrum. As a result, if the analysis assumes a soft spectrum (such as optically thin thermal bremsstrahlung) an absorption feature might appear, whereas a harder spectrum (such as a Comptonized blackbody) would not require the feature. Since the continuum shape probably changes during the duration of a typical burst, the nonuniqueness of the spectral unfolding, combined with the assumption that the continuum is optically thin thermal bremsstrahlung, could give rise to spurious absorption features which vary on a time scale of seconds. Despite these problems, there is still some evidence for narrow spectral lines in the range 45 to 65 keV but not for the broad lines reported from the Konus experiment. Unfortunately, the range 45 to 65 keV is the most difficult spectral region to unfold.
Proceedings of the Gamma Ray Observatory Science Workshop
Author: W. Neil Johnson
Publisher:
ISBN:
Category : Astrophysics
Languages : en
Pages : 764
Book Description
Publisher:
ISBN:
Category : Astrophysics
Languages : en
Pages : 764
Book Description