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The Slow X -Ray Expansion of the N orthwestern R im of Vela Jr.

The Slow X -Ray Expansion of the N orthwestern R im of Vela Jr. . Vela Jr. NW rim (XMM). Satoru Katsuda (1, 2), Hiroshi Tsunemi (1), & Koji Mori (3) (1. Osaka U.; 2. NASA/GSFC; 3. Miyazaki U.). Vela Jr. (ROSAT). This talk is based on ApJ , 678, L35 (2008). Vela Jr. SNR.

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The Slow X -Ray Expansion of the N orthwestern R im of Vela Jr.

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  1. The Slow X-Ray Expansion of the Northwestern Rim of Vela Jr. Vela Jr. NW rim(XMM) Satoru Katsuda (1, 2), Hiroshi Tsunemi (1), & Koji Mori (3) (1. Osaka U.; 2. NASA/GSFC; 3. Miyazaki U.) Vela Jr.(ROSAT) This talk is based on ApJ, 678, L35 (2008)

  2. Vela Jr. SNR ROSAT all-sky survey H.E.S.S. 0.5-20 TeV Radio (4850MHz) 0.1-2.4 keV 1.3-2.4 keV • Discovered byROSAT (Aschenbach 1998). • High energyX-rays ⇒ Young(<1500yr)Large (R~1deg)⇒Near(<1kpc) • SN Type ：Core-collapse (?) • A possible candidate of a neutron star around the center of the SNR(Slane+2001; Kargaltsev+2002).But, the age (a few 1000 yr) and the distance (>~1kpc) are not consistent with those of Vela Jr.⇒ need confirmation of the relation Aschenbach (1998) Aharonian+ (2007) Stupar+ (2005) ASCA GIS image Slane+2001

  3. X-ray wideband X-ray hard band 44Ti Decay Line (Aschenbach 1998) (Aschenbach 1998) • COMPTEL detected 44Ti decay g-ray line (Iyudin+ 1998), making Vela Jr. the 2nd object from which 44Ti line was detected (1st was Cas A).44Ti → 44Sc+2g→ 44Ca+g • Very young (~700 yr) • Very near (~200 pc) t~8 hr t~90 yr 44Ti g-ray line image @1.157 MeV Iyudin+ (1998)

  4. Detection of K Lines from Ca (Sc) Line feature ROSAT image of Vela Jr. XMM-Newton(Iyudin+2005) He-like 44Ca Ka Chandra (Bamba+2005) ASCA SIS0 (Tsunemi+2000) Line feature The age estimated from the amount of 44Ca and 44Ti is~1000 yr(Tsunemi+2000).

  5. Doubt for the Distance (and Age)~Radio Observations~ 4.85 GHz Radio Image S-D plot (Duncan & Green 2000) Duncan & Green (2000) Radio surface brightness If d = 200 pc ⇒ Very unusual If d = 1 kpc ⇒ Normal Vela Jr. SNR radius

  6. Doubts for Age and Distance~g- and X-ray Observations~ 44Ti g-ray line images Doubts for Age：- Re-analysis of COMPTEL data showed only 2 s significance of the 44Ti decay line (Schonfelder+ 2000).- ASCA SIS1 did not detectthe line feature around 4 keV (Slane+ 2001). ⇒Is the detection of 44Ti true?⇒Is Vela Jr. so young? Doubts for Distance：The interstellar absorptionfor Vela Jr. is 10 times larger than that for the Vela SNR (Slane+2001) ⇒Is Vela Jr. so close? Result in 2000 Result in 1998 RX J0852 (Schonfelder+2000) (Iyudin+1998) ASCA GIS spectra Slane+ (2001) 1 2 5 (keV)

  7. Our Approach • Measure the expansion rate of Vela Jr. The first expansion measurement for this SNR. • Estimate the age and the distance based on the expansion rate. • Discuss • the relation between Vela Jr. and the possible candidate of the neutron star. • the detection of emission lines related 44Ti.

  8. XMM-Newton Observations of Vela Jr. Obs. Date Exp. Time 1. 04/25/2001 31 ks 2. 06/22/2003 26 ks 3. 11/01/2005 64 ks 4. 10/24/2007 63 ks XMM-Newton image 6.5 yr ROSAT image ~60’ - Radius: ~60’ - Age: ~700 yr Red: 0.4-1keVGreen: 1-1.5 keVBlue: 1.5-8 keV Mean velocity ~ 35”/6.5 yrs

  9. Astrometric Accuracy XMM hard band (1.5-8 keV) image Absolute position accuracy of XMM-Newton is ~2” (Kirsch 2007). We investigated the positions of 4 point sources in each observation.⇒We confirmed that all sources are detected within 2” circles. ⇒We take 2” as a systematic error. 5 arcmin

  10. Difference Image Hard band image (2001) Difference Image (2001-2007) 5 arcmin The motion of the shock can be seen as a black filament.

  11. X-ray image Radial Profile Proper motion ~5”/6.5 yr Quantitative shift estimation l : shift parameter, k: bin Shift the 2001 profile, and compare it with 2003, 2005, or 2007 profiles. ⇒Search for the best-shift position which minimizes the c2 –value.

  12. c2 Distribution 2001-20032001-20052001-2007 6arcseconds Proper motion ⇒0.84”±0.23” yr-1. Expansion rate ⇒0.023±0.006% (=0.84”/60’) yr-1.

  13. Expansion Index ~Comparison with other SNRs~ Free expansion 1 Vela Jr. 1☆: Cas A (e.g., Vink+ 1998) 2☆: Kepler (This work; Vink 2008) 4 3☆: Tycho (Reynoso+ 1997; This work) 2 4☆: SN 1006 (Moffett+ 1993; This work) 3 5☆: Cygnus Loop (Blair+ 2005) Sedov Snowplow Vela Jr. : ~1000–3000 年 5

  14. Estimation of the Distance Dominated by nonthermalemission (Tsunemi+2000; Slane+2001; Bamba+ 2005) Slane+ (2001) In general, nonthermally-dominated shockshave high shock velocities of >3000 km/sec (e.g., Uchiyama+ 2003). D >~750 (v/3000 km sec-1)(μ/0”.84 yr-1) pc.

  15. Relation between Vela Jr. and NS • － AX J0851.9-4617.4 － • Age: ~ A few 103 yr (Kargaltsev+ 2002) • Distance: Farther than the Vela SNR (Slane+ 2001; Kargaltsev+ 2002) . ⇒Consistent with the age of Vela Jr. estimated here (1000–3000 yr) AX J0851.9-4617.4 ASCA GIS 0.7-10keV ⇒ Consistent with the distance of Vela Jr. estimated here. Slane+ (2001) The NS candidate is strongly suggested to be the stellar remnant ofVela Jr. SNR.

  16. On the Detection of 44Ti Decay Line Based on the newly estimated age and distance, the initial amount of 44Ti is calculated to be ~solar mass (if we believe the detection by Iyudin+1998) ⇒Probably, the g-ray emission detected by COMPTEL has no relation to Vela Jr. 44Ti g-ray line image Iyudin+ (1998) Age effect: The new age (1000–3000 yr) is about twice that of 680 yr. Since the 44Ti decays exponentially with time, the initial amount of 44Ti increases by 4000 times of that estimated in Iyudin+1998. Distance effect: The new distance is at least 4 larger than that estimated previously.⇒The amount of 44Ti increases 16 times.

  17. Summary • We, for the first time, measured the expansion of Vela Jr. with XMM-Newton. We found that the expansion rate is 0.84”±0.23” yr-1, which is only1/7of the free expansion. • The relation between expansion index and the age of SNRs indicates that the age and the distance of Vela Jr. are~1000–3000 yrand >~750 pc, respectively. • Neutron star: The newly estimated ageand distance are consistent with those of the NS candidate.⇒The NS candidate is likelythe very NS left behind the SN explosion which produced Vela Jr. • 44Ti: The newly estimated age and distance indicates no detection of44Ti from Vela Jr.⇒Probably, the emission line from 44Ti detected by Iyudin+1998 is not related to Vela Jr.

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