Overabundance of Calcium in the Young SNR RX J0852–4622: Evidence of Over-Production of 44Ti

Abstract

Recently, COMPTEL has detected γ-rays of 1157 keV from 44 Ti in the direction of the SNR RX J0852−4622 (Iyudin et al. 1998). Since 44 Ti is a product of explosive nucleosynthesis and its half lifetime τ 1/2 is about 60 yrs, RX J0852−4622 must be a young supernova remnant and radiation is dominated by the ejecta rather than by interstellar matter. We have detected an X-ray emission line at 4.1 ± 0.2 keV which is thought to come from highly ionized Ca. The emission line is so far only seen in the north-west shell region of RX J0852−4622. The X-ray spectrum can be well fitted with that of thin hot plasma of cosmic abundances except that of Ca, which is overabundant by a factor of 8 ± 5. Assuming that most of Ca is 44 Ca, which originates from 44 Ti by radioactive decay, we estimate a total Ca mass of about 1.1 × 10 −3 M ⊙ . Combining the amount of 44 Ca and the observed flux of the 44 Ti γ-ray line, the age of RX J0852−4622 is around 1000 yrs.

ChandraObservations of Galactic Supernova Remnant Vela Jr.: A New Sample of Thin Filaments Emitting Synchrotron X‐Rays

“…There is some linelike feature below 2 keV, which probably comes from thermal emission of Vela and/or Vela Jr., as already mentioned (Slane et al 2001). ( Tsunemi et al 2000). The gray scale is logarithmic, and coordinates are J2000.0.…”

“…Figure 1 shows the ASCA (Advanced Satellite for Cosmology and Astrophysics) GIS image ( Tsunemi et al 2000) with the field of view of the Chandra observations. The satellite and the instrument are described by Weisskopf et al (2002) and Garmire et al (2000), respectively.…”

Nonthermal emission properties of the northwestern rim of supernova remnant RX J0852.0-4622

“…Iyudin et al (1998) estimated an age of ∼680 yr and the distance of ∼200 pc based on the flux of 44 Ti lines detected with COMPTEL onboard the Compton Gamma-Ray Observatory. Tsunemi et al (2000) estimated a similar age of between 630 and 970 yr based on observations of Ca X-ray lines with ASCA. These estimates imply that RX J0852.0-4622 belongs to the supernovae that are closest to Earth.…”

Prospects for Cherenkov Telescope Array Observations of the Young Supernova Remnant RX J1713.7−3946

“…We are also aware that some of these characteristics are common among several other young SNRs, including RXJ0852.0−4622 (Aharonian et al 2005(Aharonian et al , 2007bKatagiri et al 2005), RCW86 ), and HESSJ1731−347 (Abramowski et al 2011). It is noteworthy that no thermal X-ray emission has been firmly detected in these SNRs (e.g., Koyama et al 1997;Tsunemi et al 2000;Bamba et al 2012).…”