Detection of the 67.9 and 78.4 [CLC]ke[/CLC]V Lines Associated with the Radioactive Decay of [TSUP]44[/TSUP]T[CLC]i[/CLC] in Cassiopeia A

Vink, Jacco; Laming, J. M.; Kaastra, J. S.; Bleeker, J. A. M.; Bloemen, H.; Oberlack, U.

doi:10.1086/324172

Cited by 138 publications

(177 citation statements)

References 27 publications

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“…The measured expansion velocities, however, are similar to those from a Gaussian fit, and systematic differences are smaller than uncertainties from statistics. When the results of The et al (1996) obtained with OSSE on CGRO with the COMPTEL result by Iyudin et al (1997), the BeppoSAX result (Vink et al 2001), the INTEGRAL/IBIS result (Renaud et al 2006), and the NuStar result (Grefenstette et al 2014) are combined with our work through a weighted mean (weighted by the inverse variance of each measurement), the 44 Ti mass is (1.37 ± 0.19) × 10 −4 M .…”

Section: Ti Gamma-ray Line Measurementsmentioning

confidence: 62%

Revisiting INTEGRAL/SPI observations of⁴⁴Ti from Cassiopeia A

Siegert

Diehl

Krause

et al. 2015

A&A

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Context. The 340-yr old supernova remnant Cassiopeia A, located at 3.4 kpc distance, is the best-studied young core-collapse supernova remnant. Nucleosynthesis yields in radioactive isotopes have been studied with different methods, in particular for production and ejection of 44 Ti and 56 Ni, which originate in the innermost regions of the supernova. 44 Ti was first discovered in this remnant, but is not seen consistently in other core-collapse sources. Aims. We aim to measure radioactive 44 Ti ejected in Cassiopeia A and to place constraints on velocities of these ejecta by determining X-and γ-ray line-shape parameters of the emission lines. Methods. We analyzed the observations made with the SPI spectrometer on INTEGRAL together with an improved instrumental background method, to achieve a high spectroscopic resolution that enables interpretation for a velocity constraint on 44 Ti ejecta from the 1.157 MeV γ-ray line of the 44 Sc decay. Results. We observe both the hard X-ray line at 78 keV and the γ-ray line at 1157 keV from the 44 Ti decay chain at a combined significance of 3.8σ. Measured fluxes are (2.1 ± 0.4) × 10 −5 ph cm −2 s −1 and (3.5 ± 1.2) × 10 −5 ph cm −2 s −1 , which corresponds to (1.5 ± 0.4) × 10 −4 and (2.4 ± 0.9) × 10 −4 M of 44 Ti, respectively. The measured Doppler broadening of the lines implies expansion velocities of 4300 and 2200 km s −1 , respectively. By combining our results with previous studies, we determine a more precise estimate of ejected 44 Ti of (1.37 ± 0.19) × 10 −4 M . Conclusions. The measurements of the two lines are consistent with previous studies. The flux in the line originating from excited 44 Ca is significantly higher than the flux determined in the lines from 44 Sc. Cosmic-ray acceleration within the supernova remnant may be responsible for an additional contribution to this line from nuclear de-excitation following energetic particle collisions in the remnant and swept-up material.

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Section: Ti Gamma-ray Line Measurementsmentioning

confidence: 62%

Revisiting INTEGRAL/SPI observations of⁴⁴Ti from Cassiopeia A

Siegert

Diehl

Krause

et al. 2015

A&A

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“…Only in one case, Cas A, has such a detection been made (Iyudin et al 1994;Vink et al 2001), with the mass estimated to 1.6 +0.6 −0.3 × 10 −4 M (Renaud et al 2006). For Cas A we do not know the masses of the 56 Ni and 57 Ni isotopes though.…”

Section: Introductionmentioning

confidence: 98%

The⁴⁴Ti-powered spectrum of SN 1987A

Jerkstrand

Fransson

Kozma

2011

A&A

172

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SN 1987A provides a unique opportunity to study the evolution of a supernova from explosion into very late phases. Owing to the rich chemical structure, the multitude of physical processes involved and extensive radiative transfer effects, detailed modeling is needed to interpret the emission from this and other supernovae. In this paper, we analyze the late-time (about eight years) Hubble Space Telescope spectrum of the SN 1987A ejecta, where 44 Ti is the dominant power source. Based on an explosion model for a 19 M progenitor, we compute a model spectrum by calculating the degradation of positrons and gamma-rays from the radioactive decays, solving the equations governing temperature, ionization balance and NLTE level populations, and treating the radiative transfer with a Monte Carlo technique. We obtain a UV/optical/NIR model spectrum that reproduces most of the lines in the observed spectrum with good accuracy. We find non-local radiative transfer in atomic lines to be an important process also at this late stage of the supernova, with ∼30% of the emerging flux in the optical and NIR coming from scattering/fluorescence. We investigate the question of where the positrons deposit their energy, and favor the scenario where they are locally trapped in the Fe/He clumps by a magnetic field. Energy deposition into these largely neutral Fe/He clumps makes Fe I lines prominent in the emerging spectrum. With the best available estimates for the dust extinction, we determine the amount of 44 Ti produced in the explosion to be 1.5 +0.5 −0.5 × 10 −4 M .

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“…This was in particular apparent for Cas A, which is detected in hard X-rays from ∼ 10 − 100 keV, indicating a nearly power-law like spectrum with index ∼ 3.2 Allen et al, 1997;Favata et al, 1997;Vink et al, 2001;Renaud et al, 2006). For other supernova remnants hard X-ray emission up to about 30 keV was detected (e.g.…”

Section: X-ray Observationsmentioning

confidence: 90%

Observational Signatures of Particle Acceleration in Supernova Remnants

Helder¹,

Vink²,

Bykov³

et al. 2012

Particle Acceleration in Cosmic Plasmas

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We evaluate the current status of supernova remnants as the sources of Galactic cosmic rays. We summarize observations of supernova remnants, covering the whole electromagnetic spectrum and describe what these observations tell us about the acceleration processes by high Mach number shock fronts. We discuss the shock modification by cosmic rays, the shape and maximum energy of the cosmic-ray spectrum and the total energy budget of

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Detection of the 67.9 and 78.4 [CLC]ke[/CLC]V Lines Associated with the Radioactive Decay of [TSUP]44[/TSUP]T[CLC]i[/CLC] in Cassiopeia A

Cited by 138 publications

References 27 publications

Revisiting INTEGRAL/SPI observations of⁴⁴Ti from Cassiopeia A

Revisiting INTEGRAL/SPI observations of⁴⁴Ti from Cassiopeia A

The⁴⁴Ti-powered spectrum of SN 1987A

Observational Signatures of Particle Acceleration in Supernova Remnants

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Detection of the 67.9 and 78.4 [CLC]ke[/CLC]V Lines Associated with the Radioactive Decay of [TSUP]44[/TSUP]T[CLC]i[/CLC] in Cassiopeia A

Cited by 138 publications

References 27 publications

Revisiting INTEGRAL/SPI observations of44Ti from Cassiopeia A

Revisiting INTEGRAL/SPI observations of44Ti from Cassiopeia A

The44Ti-powered spectrum of SN 1987A

Observational Signatures of Particle Acceleration in Supernova Remnants

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Product

Resources

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Revisiting INTEGRAL/SPI observations of⁴⁴Ti from Cassiopeia A

Revisiting INTEGRAL/SPI observations of⁴⁴Ti from Cassiopeia A

The⁴⁴Ti-powered spectrum of SN 1987A