Primary particle acceleration above 100 TeV in the shell-type supernova remnant RX J1713.7-3946 with deep HESS observations

Abstract

Aims: We present deep HESS observations of the supernova remnant (SNR) RX J1713.7-3946. Combining data of three years – from 2003 to 2005 – we obtain significantly increased statistics and energy coverage as compared to earlier 2003 and 2004 results.

Methods: The data are analysed separately for the different years.

Results: Very good agreement of the gamma-ray morphology and the differential spectra is found when comparing the three years. The combined gamma-ray image of the 2004 and 2005 data reveals the morphology of RX J1713.7-3946 with unprecedented precision. An angular resolution of 0.06° is achieved, revealing the detailed structure of the remnant. The combined spectrum of all three years extends over three orders of magnitude, with significant gamma-ray emission approaching 100 TeV. The cumulative significance above 30 TeV is 4.8σ, while for energies between 113 and 294 TeV an upper limit on the gamma-ray flux of 1.6× 10-16 cm-2 s-1 is obtained.

Conclusions: The energy coverage of the HESS data is presumably at the limit of present generation Cherenkov telescopes. The measurement of significant gamma-ray emission beyond 30 TeV formally implies the existence of primary particles of at least that energy. However, for realistic scenarios of very-high-energy gamma-ray production, the Inverse Compton scattering of very-high-energy electrons and π0 decay following inelastic proton-proton interactions, the measured gamma-ray energies imply that efficient acceleration of primary particles to energies exceeding 100 TeV is taking place in the shell of the SNR RX J1713.7-3946.

Astronomy & Astrophysics 464, 235-243 (2007)
ArXiv pre-print
Erratum

Auxiliary informations

H.E.S.S. images shown in Figure 1 (years 2003, 2004, 2005)

FITS image 2003
FITS image 2004
FITS image 2005

Remark: Gamma-ray excess images smoothed with Gaussian, see paper caption.

H.E.S.S. data points for Figure 1

Slice 2003

  low          up        Excess events      Error
     (degrees)
-1.00        -0.89           -0.53          11.43
-0.89        -0.79          -15.47           9.68
-0.79        -0.68           -0.50          10.36
-0.68        -0.58           24.20          11.41
-0.58        -0.47           80.77          13.74
-0.47        -0.37           75.42          13.25
-0.37        -0.26           65.51          12.65
-0.26        -0.16           76.29          12.94
-0.16        -0.05           72.88          12.70
-0.05         0.05           82.09          13.44
 0.05         0.16          119.60          14.31
 0.16         0.26          125.17          14.49
 0.26         0.37          127.53          14.55
 0.37         0.47          105.18          13.78
 0.47         0.58           60.97          12.10
 0.58         0.68           14.21          10.05
 0.68         0.79            5.29           9.65
 0.79         0.89            6.05           9.79
 0.89         1.00            0.51           9.97

Slice 2004

  low          up        Excess events      Error
     (degrees)
-1.00        -0.89           -4.92           5.65
-0.89        -0.79           -6.61           5.34
-0.79        -0.68           -4.39           5.31
-0.68        -0.58           14.02           5.62
-0.58        -0.47           42.36           6.11
-0.47        -0.37           63.47           6.42
-0.37        -0.26           73.63           6.54
-0.26        -0.16           70.39           6.45
-0.16        -0.05           80.61           6.61
-0.05         0.05           87.68           6.95
 0.05         0.16          115.14           7.16
 0.16         0.26          131.50           7.43
 0.26         0.37          139.36           7.58
 0.37         0.47          136.25           7.61
 0.47         0.58           59.27           6.43
 0.58         0.68            9.52           5.54
 0.68         0.79           10.89           5.65
 0.79         0.89            8.65           5.70
 0.89         1.00           -1.64           5.74

Slice 2005

  low          up        Excess events      Error
     (degrees)
-1.00        -0.89           -4.04           6.24
-0.89        -0.79            1.33           6.12
-0.79        -0.68           -3.47           5.91
-0.68        -0.58            8.16           6.18
-0.58        -0.47           43.01           7.05
-0.47        -0.37           65.91           7.54
-0.37        -0.26           76.27           7.74
-0.26        -0.16           81.81           7.82
-0.16        -0.05           82.88           7.84
-0.05         0.05           77.91           8.00
 0.05         0.16          112.80           8.46
 0.16         0.26          121.96           8.68
 0.26         0.37          140.46           9.07
 0.37         0.47          115.92           8.66
 0.47         0.58           60.18           7.52
 0.58         0.68           21.11           6.62
 0.68         0.79            7.66           6.31
 0.79         0.89            5.50           6.34
 0.89         1.00            9.81           6.78

Az. Profile 2003

 low         up     Excess events      Error
    (degrees)
-180       -150         23.44           8.38
-150       -120         27.97           8.81
-120        -90         31.34           8.89
 -90        -60         46.30           9.87
 -60        -30         69.69          10.85
 -30          0         59.05          10.16
   0         30         69.14          10.70
  30         60         66.03          10.45
  60         90         54.84          10.15
  90        120         37.85           9.05
 120        150         68.47          10.78
 150        180         46.65           9.73

Az. Profile 2004

 low         up     Excess events      Error
    (degrees)
-180       -150         26.61           4.07
-150       -120         22.02           4.00
-120        -90         41.19           4.42
 -90        -60         39.39           4.47
 -60        -30         60.04           4.88
 -30          0         70.98           5.07
   0         30         68.79           5.08
  30         60         66.44           5.00
  60         90         52.65           4.81
  90        120         49.84           4.63
 120        150         55.51           4.79
 150        180         47.30           4.59

Az. Profile 2005

 low         up     Excess events      Error
    (degrees)
-180       -150         31.29           5.06
-150       -120         31.62           5.13
-120        -90         39.23           5.30
 -90        -60         41.77           5.49
 -60        -30         62.91           6.05
 -30          0         58.48           5.90
   0         30         69.00           6.25
  30         60         76.50           6.40
  60         90         54.79           5.94
  90        120         43.72           5.47
 120        150         46.12           5.58
 150        180         45.34           5.55

Rad. Profile 2003

 low           up      Excess events       Error
     (degrees)
0.00          0.10         0.28            0.08
0.10          0.20         0.37            0.05
0.20          0.30         0.44            0.04
0.30          0.40         0.47            0.03
0.40          0.50         0.37            0.03
0.50          0.60         0.27            0.02
0.60          0.70         0.05            0.02
0.70          0.80         0.03            0.02
0.80          0.90        -0.01            0.02
0.90          1.00        -0.01            0.01
1.00          1.10         0.00            0.01
1.10          1.20        -0.00            0.01
1.20          1.30        -0.00            0.01
1.30          1.40         0.02            0.02

Rad. Profile 2004

 low           up      Excess events       Error
     (degrees)
0.00          0.10         0.31            0.04
0.10          0.20         0.34            0.02
0.20          0.30         0.44            0.02
0.30          0.40         0.47            0.02
0.40          0.50         0.41            0.01
0.50          0.60         0.18            0.01
0.60          0.70         0.06            0.01
0.70          0.80         0.03            0.01
0.80          0.90         0.02            0.01
0.90          1.00         0.01            0.01
1.00          1.10         0.00            0.01
1.10          1.20         0.00            0.01
1.20          1.30         0.00            0.01
1.30          1.40         0.01            0.01

Rad. Profile 2005

 low           up      Excess events       Error
     (degrees)
0.00          0.10         0.33            0.05
0.10          0.20         0.32            0.03
0.20          0.30         0.45            0.02
0.30          0.40         0.49            0.02
0.40          0.50         0.39            0.02
0.50          0.60         0.18            0.01
0.60          0.70         0.04            0.01
0.70          0.80         0.02            0.01
0.80          0.90         0.02            0.01
0.90          1.00         0.01            0.01
1.00          1.10         0.01            0.01
1.10          1.20        -0.02            0.01
1.20          1.30         0.02            0.01
1.30          1.40         0.02            0.01

Remarks: Bottom panel of the figure. Given are always the bin edges, low and up, and the bin contents plus statistical error bars.

H.E.S.S. image shown in Figure 2

FITS image

Remark: See figure caption for details.

H.E.S.S. data points for Figure 3

 #     E        Energy Flux      Error_low   Error_high

     (TeV)   | ------- (TeV^-1 cm^-2 s^-1) --------  |

 ---------------------- 2003 -------------------------

 0    0.79      1.53e-11         4.04e-12    4.03e-12
 1    1.03      1.80e-11         2.47e-12    2.49e-12
 2    1.37      1.57e-11         2.27e-12    2.29e-12
 3    1.82      2.07e-11         2.02e-12    2.05e-12
 4    2.42      1.85e-11         1.82e-12    1.87e-12
 5    3.23      1.06e-11         1.84e-12    1.88e-12
 6    4.29      1.52e-11         1.92e-12    1.98e-12
 7    5.72      1.10e-11         1.98e-12    2.04e-12
 8    7.61      1.05e-11         2.09e-12    2.17e-12
 9   10.13      1.35e-11         2.39e-12    2.50e-12
10   13.50      4.71e-12         2.25e-12    2.33e-12
11   17.97      6.18e-12         1.97e-12    2.18e-12
12   23.92      5.77e-12         1.97e-12    2.31e-12
13   33.32      3.47e-12         1.98e-12    2.23e-12
14   53.10      7.29e-12         3.40e-12    3.65e-12

 ---------------------- 2004 -------------------------

 0    0.31      2.39e-11         3.31e-12    3.31e-12
 1    0.38      1.91e-11         2.46e-12    2.46e-12
 2    0.46      2.05e-11         2.11e-12    2.11e-12
 3    0.55      2.04e-11         1.92e-12    1.92e-12
 4    0.67      2.28e-11         1.79e-12    1.79e-12
 5    0.81      1.75e-11         1.69e-12    1.69e-12
 6    0.98      2.15e-11         1.64e-12    1.64e-12
 7    1.19      1.92e-11         1.62e-12    1.62e-12
 8    1.43      1.77e-11         1.65e-12    1.65e-12
 9    1.74      2.02e-11         1.67e-12    1.67e-12
10    2.10      1.92e-11         1.68e-12    1.69e-12
11    2.54      1.85e-11         1.73e-12    1.74e-12
12    3.08      1.80e-11         1.86e-12    1.87e-12
13    3.73      1.49e-11         1.95e-12    1.95e-12
14    4.51      1.51e-11         1.97e-12    1.98e-12
15    5.46      1.56e-11         1.98e-12    1.99e-12
16    6.61      1.61e-11         2.08e-12    2.10e-12
17    8.01      1.18e-11         2.05e-12    2.07e-12
18    9.69      1.24e-11         2.08e-12    2.10e-12
19   11.73      8.22e-12         2.19e-12    2.22e-12
20   14.20      6.64e-12         2.29e-12    2.31e-12
21   17.19      7.23e-12         2.06e-12    2.10e-12
22   22.83      4.39e-12         1.56e-12    1.58e-12
23   46.96      1.43e-12         8.08e-13    8.18e-13

 ---------------------- 2005 -------------------------

 0    0.55      2.10e-11         5.32e-12    5.33e-12
 1    0.80      1.89e-11         2.71e-12    2.72e-12
 2    1.16      1.88e-11         1.80e-12    1.80e-12
 3    1.68      2.15e-11         1.56e-12    1.56e-12
 4    2.46      1.84e-11         1.47e-12    1.48e-12
 5    3.61      1.81e-11         1.53e-12    1.53e-12
 6    5.28      1.76e-11         1.64e-12    1.64e-12
 7    7.73      1.09e-11         1.78e-12    1.78e-12
 8   11.30      9.81e-12         1.80e-12    1.80e-12
 9   16.54      5.66e-12         1.80e-12    1.81e-12
10   24.21      4.05e-12         1.80e-12    1.80e-12
11   35.43      8.50e-12         1.77e-12    1.78e-12
12   61.78      8.61e-13         8.60e-13    1.14e-12
13  126.93      1.95e-12         1.48e-12    1.51e-12

Energy flux points for 2003, 2004, and 2005 separately, see figure caption.

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