the slow x -ray expansion of the n orthwestern r im of vela jr
DESCRIPTION
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. - PowerPoint PPT PresentationTRANSCRIPT
The Slow X-Ray Expansion of the Northwestern Rim of Vela Jr.
Satoru Katsuda (1, 2), Hiroshi Tsunemi (1), & Koji Mori (3)(1. Osaka U.; 2. NASA/GSFC; 3. Miyazaki U.)
Vela Jr.(ROSAT)
Vela Jr. NW rim(XMM)
This talk is based on ApJ, 678, L35 (2008)
Vela Jr. SNRROSAT all-sky survey
Aschenbach (1998)
Discovered by ROSAT (Aschenbach 1998). High energy X-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⇒
Aharonian+ (2007)
H.E.S.S. 0.5-20 TeV Radio (4850MHz)
Stupar+ (2005)
ASCA GIS image
Slane+2001
0.1-2.4 keV1.3-2.4 keV
44Ti Decay Line
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
ÞVery young (~700 yr) ÞVery near (~200 pc)
t~90 yr t~8 hr
44Ti g-ray line image @1.157 MeV Iyudin+ (1998)
X-ray hard band(Aschenbach 1998)X-ray wideband
(Aschenbach 1998)
Detection of K Lines from Ca (Sc)
The age estimated from the amount of 44Ca and 44Ti is ~1000 yr (Tsunemi+2000).
ROSAT image of Vela Jr.
ASCA SIS0 (Tsunemi+2000)
He-like 44Ca Ka Chandra (Bamba+2005)
Line feature
XMM-Newton(Iyudin+2005)
Line feature
Doubt for the Distance (and Age)~Radio Observations~
Duncan & Green (2000)
S-D plot(Duncan & Green 2000)
4.85 GHz Radio Image
Vela Jr.
SNR radius
Rad
io s
urfa
ce b
right
ness
If d = 200 pc Very unusual ⇒
If d = 1 kpc Normal⇒
Doubts for Age and Distance~g- and X-ray Observations~
Doubts for Age :- Re-analysis of COMPTEL data showed only 2 s significance of the 44Ti decay line (Schonfelder+ 2000).- ASCA SIS1 did not detect the line feature around 4 keV (Slane+ 2001).⇒Is the detection of 44Ti true?
Is Vela Jr. so young?⇒Doubts for Distance :The interstellar absorption for Vela Jr. is 10 times larger than that for the Vela SNR (Slane+2001)⇒Is Vela Jr. so close?
ASCA GIS spectra
Slane+ (2001)
RX J0852
44Ti g-ray line images
(Schonfelder+2000)
1 2 5 (keV)
Result in 1998 Result in 2000
(Iyudin+1998)
Our ApproachMeasure 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.
XMM-Newton Observations of Vela Jr.Obs. Date Exp. Time
1. 04/25/2001 31 ks2. 06/22/2003 26 ks3. 11/01/2005 64 ks4. 10/24/2007 63 ks
- Radius: ~60’ - Age: ~700 yr
Red: 0.4-1keVGreen: 1-1.5 keVBlue: 1.5-8 keV
Mean velocity ~ 35”/6.5 yrs
6.5 yr
~60’
XMM-Newton image
ROSAT image
Astrometric Accuracy
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.
XMM hard band (1.5-8 keV) image
5 arcmin
Difference Image
5 arcmin
The motion of the shock can be seen as a black filament.
Hard band image (2001) Difference Image (2001-2007)
Radial Profile
n
k klkkxlkxl
122
21
2212
)()()()(
ss
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 2
–value.
Proper motion ~5”/6.5 yr
X-ray image
2 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.
Expansion Index ~Comparison with other SNRs~
5 : Cygnus Loop (Blair+ 2005)☆4 : SN 1006 (Moffett+ 1993; This work)☆
1 : Cas A (e.g., Vink+ 1998)☆2 : Kepler (This work; Vink 2008) ☆3 : Tycho (Reynoso+ 1997; This work)☆
1
23
4
5
tRm
Free expansion
Sedov
Snowplow
Vela Jr.
Vela Jr. : ~1000–3000 年
Estimation of the Distance
In general, nonthermally-dominated shocks have high shock velocities of >3000 km/sec (e.g., Uchiyama+ 2003).
SNR Shock velocitySN1006 (NE rim) 5000 km/sec
Kepler 4200 km/sec
Tycho 3300 km/sec
Cas A 3200 km/sec
Dominated by nonthermal emission (Tsunemi+2000; Slane+2001; Bamba+ 2005)
D >~750 (v/3000 km sec-1)(μ/0”.84 yr-1) pc.
Slane+ (2001)
Relation between Vela Jr. and NS
Slane+ (2001)
ASCA GIS 0.7-10keV
AX J0851.9-4617.4
- 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 distance of
Vela Jr. estimated here.
⇒Consistent with the age of Vela Jr. estimated here (1000–3000 yr)
The NS candidate is strongly suggested to be the stellar remnant of Vela Jr. SNR.
On the Detection of 44Ti Decay Line
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.
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)
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 yr and >~750 pc, respectively.
Neutron star: The newly estimated age and distance are consistent with those of the NS candidate.
The NS candidate is likely the very NS left behind the ⇒SN explosion which produced Vela Jr.
44Ti: The newly estimated age and distance indicates no detection of 44Ti from Vela Jr.
Probably, the emission line from ⇒ 44Ti detected by Iyudin+1998 is not related to Vela Jr.