Titanium hidden in dust

Iyudin, A. F.; Müller, Ewald; Obergaulinger, M.

doi:10.1093/mnras/stz419

Cited by 5 publications

(3 citation statements)

References 85 publications

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“…The presence of dust grains composed of ejecta material in the vicinity of the supernova remnant or in the line of sight towards the supernova remnant can alter the observed flux ratios beyond the branching ratios. Attenuation coefficients for 68 and 78 keV photons are higher than for the 1157 keV line (Iyudin et al 2019) for common dust grain compositions. Including correction for branching ratios, we derived the following flux ratio:…”

Section: A83 Page 8 Of 15mentioning

confidence: 76%

⁴⁴Ti ejecta in young supernova remnants

Weinberger

Diehl

Pleintinger

et al. 2020

A&A

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Context. Tracing unstable isotopes produced in supernova nucleosynthesis provides a direct diagnostic of supernova explosion physics. Theoretical models predict an extensive variety of scenarios, which can be constrained through observations of the abundant isotopes 56Ni and 44Ti. Direct evidence of the latter was previously found only in two core-collapse supernova events, and appears to be absent in thermonuclear supernovae. Aims. We aim to to constrain the supernova progenitor types of Cassiopeia A, SN 1987A, Vela Jr., G1.9+0.3, SN1572, and SN1604 through their 44Ti ejecta masses and explosion kinematics. Methods. We analyzed INTEGRAL/SPI observations of the candidate sources utilizing an empirically motivated high-precision background model. We analyzed the three dominant spectroscopically resolved de-excitation lines at 68, 78, and 1157 keV emitted in the decay chain of 44Ti→44Sc→44Ca. The fluxes allow the determination of the production yields of 44Ti. Remnant kinematics were obtained from the Doppler characteristics of the lines. Results. We find a significant signal for Cassiopeia A in all three lines with a combined significance of 5.4σ. The fluxes are (3.3 ± 0.9) × 10−5 ph cm−2 s−1, and (4.2 ± 1.0) × 10−5 ph cm−2 s−1 for the 44Ti and 44Sc decay, respectively. This corresponds to a mass of (2.4 ± 0.7) × 10−4 M⊙ and (3.1 ± 0.8) × 10−4 M⊙, respectively. We obtain higher fluxes for 44Ti with our analysis of Cassiopeia A than were obtained in previous analyses. We discuss potential differences. We interpret the line width from Doppler broadening as expansion velocity of (6400 ± 1900) km s−1. We do not find any significant signal for any other candidate sources. Conclusions. We obtain a high 44Ti ejecta mass for Cassiopeia A that is in disagreement with ejecta yields from symmetric 2D models. Upper limits for the other core-collapse supernovae are in agreement with model predictions and previous studies. The upper limits we find for the three thermonuclear supernovae (G1.9+0.3, SN1572 and SN1604) consistently exclude the double detonation and pure helium deflagration models as progenitors.

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Section: A83 Page 8 Of 15mentioning

confidence: 76%

⁴⁴Ti ejecta in young supernova remnants

Weinberger

Diehl

Pleintinger

et al. 2020

A&A

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“…Using the emission measure as a proxy for element mass, Holland-Ashford et al ( 2020) infer stronger asymmetries with increasing element mass. Iyudin et al (2019) speculate that the 44 Ti may be trapped in dust grains, since the fluxes of 67.9 and 78.4 keV photons from the nuclear de-excitation of 44 Sc are marginally lower than the 1157 keV 44 Ca lines, and at lower energy may be absorbed more. The plausibility of the Ti condensing out of the hot Fe-Co-Ni bubble to form grains while the Fe apparently does not is not discussed, but such a mechanism also offers an explanation of the different morphologies observed in 44 Ti and Fe.…”

Section: Radioactivity and Estimates For Fementioning

confidence: 96%

Element Abundances in the Unshocked Ejecta of Cassiopeia A

Laming,

Temim

2020

Preprint

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We analyze and model the infrared spectrum of the Cassiopeia A supernova remnant, with the aim of determining the masses of various elements in the unshocked ejecta. In this way we complement the survey of the X-ray emitting ejecta of Hwang & Laming (2012) to provide a complete census of the elemental composition of the Cas A ejecta. We calculate photoionization-recombination equilibria to determine the ionization balance of various elements in the ejecta as a function of density, using the X-ray and UV emission from the forward and reverse shocks as the ionizing radiation. With the assumption that all emission lines are principally excited at the ejecta density that maximizes their emission, we can convert observed line intensities into element masses. We find that the majority of the ∼ 3M ⊙ ejecta have already been through the reverse shock and are seen today in X-rays. A minority, ∼ 0.47 ± 0.05 M ⊙ , with uncertainties quoted here coming from the data fitting procedure only, are still expanding inside the reverse shock and emitting in the infrared. This component is comprised mainly of O, Si, and S, with no Fe detectable. Incorporating uncertainties estimated to come from our modeling, we quote 0.47 ± 0.47 0.24 M ⊙ . We speculate that up to a further 0.07 M ⊙ of Fe may be present in diffuse gas in the inner ejecta, depending on the Fe charge state.

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“…To solve this problem proposed to assume the existence of a low-energy component of cosmic rays that excites the 44 Ca emission (responsible of the 1157 kev line), but maintaining the induced emission of 44 Sc small as a consequence of its low abundance due to its short lifetime. Another possibility has been advanced by Iyudin et al (2019) (5.9 ± 1.9) × 10 −4 M when using the 1157 keV line, (2.6 ± 0.6) × 10 −4 M when using both, and (2.9 ± 0.5) × 10 −4 M , using the three lines but keeping the Doppler parameters of the 78 and 1157 keV lines. Thus, it is obvious that, to solve the problem, new observations with a more sensitive instrument are necessary.…”

Section: Thermonuclear Supernovaementioning

confidence: 99%

Synthesis of radioactive elements in novae and supernovae and their use as a diagnostic tool

Isern,

Hernanz,

Bravo

et al. 2021

Preprint

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Novae and supernovae play a key role in many fields of Astrophysics and Cosmology. Despite their importance, an accurate description of which objects explode and why and how they explode is still lacking. One of the main characteristics of such explosions is that they are the main suppliers of newly synthesized chemical elements in the Galaxy. Since some of these isotopes are radioactive, it is possible to use the corresponding gamma-rays as a diagnostic tool of the explosion thanks to their independence on the thermal state of the debris. The drawback is the poor sensitivity of detectors in the MeV energy domain. As a consequence, the radioactive lines have only been detected in one core collapse supernova (SN 1987A), one Type Ia supernova (SN 2014J), and one supernova remnant (Cas A). Nevertheless these observations have provided and are providing important information about the explosion mechanisms. Unfortunately, novae are still eluding detection. These results emphasize the necessity to place as soon as possible a new instrument in orbit with enough sensitivity to notice-

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Titanium hidden in dust

Cited by 5 publications

References 85 publications

⁴⁴Ti ejecta in young supernova remnants

⁴⁴Ti ejecta in young supernova remnants

Element Abundances in the Unshocked Ejecta of Cassiopeia A

Synthesis of radioactive elements in novae and supernovae and their use as a diagnostic tool

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Titanium hidden in dust

Cited by 5 publications

References 85 publications

44Ti ejecta in young supernova remnants

44Ti ejecta in young supernova remnants

Element Abundances in the Unshocked Ejecta of Cassiopeia A

Synthesis of radioactive elements in novae and supernovae and their use as a diagnostic tool

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⁴⁴Ti ejecta in young supernova remnants

⁴⁴Ti ejecta in young supernova remnants