SPI / Bruyère Calibration First Results
Data reduction (Imaging of the (60)Co beetween 1100 and 1400 keV).
Pixel size : 0.2*0.2 ° - Imaging method : IROS
Session of 2001/04/10 and 2001/01/11
|
Pointing
|
31 |
|
Start Time
|
21:53 |
|
End Time
|
22:14 |
|
Spi Position
|
0 |
|
Recover Position (alpha, delta)
|
(0.001, -0.006) |
|
Nb of Sigma
|
431 |
| Pointing | Start Time | End Time | SPI Pos | Recover Position | Nb of Sigma | Significance Map |
|---|---|---|---|---|---|---|
35 |
23:33 |
23:55 |
359.5 |
0.492 |
0.008 |
392 |
36 |
23:57 |
00:19 |
359 |
1.053 |
0.014 |
387 |
37 |
00:24 |
00:46 |
358 |
2.042 |
-0.06 |
374 |
38 |
00:51 |
01:12 |
356 |
3.972 |
0.027 |
379 |
N.B. : Normally, to obtain sky images with SPI, we used the dithering technique. Nevertheless, we have build images pointing by pointing which explain the apparition of the numerous ghosts. There is also a problem in the transfert function of SPI due to the absorption of the central mask element.
Imaging with the (60)Co source using dithering
We have used 14 pointings on the (60)Co with the source position varying form 0 to 8° from the telescope axis.
Then we build an observation using these 14 pointings.
Images obtained using different method : modified cross correlation, maximum entropy (memsys5) and IROS are presented on the next figures (pixel size : 0.2°*0.2°).
1. Maximun entropy
Source located at (0°,0°), integrated significance on a radius of 0.5° : 604 sigma (pixel size : 0.5°*0.5°).
2. Correlation of the mask with the detector shadowgram
3. IROS
We obtained for IROS a source of (-0.029°, + 0.007°) with 1117 sigma, the following map is the residual significance.
Imaging with the (24)Na source using dithering
We have used 19 pointings on the (24)Na.
Image resolution : 0.2°*0.2° , image size : 101*101 pixels, centered at (0°*0°).
Source intensity : 671 sigma
Imaging with the (137)Cs source using dithering, between 600 and 700 keV
We have used 66 pointings on the (137)Cs.
Image resolution : 0.2°*0.2° , image size : 101*101 pixels, centered at (0°*0°).
Source intensity : 1912 sigma
The source position found is (-0.047°, -0.018°)
Position of the (137)Cs source for different pointings.
Pointing number : 86
Spi Axe : 358.0° - Rotation : 0°
Source position found : (-2.052°, -0.014°)
Flux : 0.45 (arbitrary unit)
Pointing number : 223
Spi Axe : 358.5° - Rotation : 30°
Source position found : (1.436°, -0.847°)
Flux : 0.45 (arbitrary unit)
Pointing number : 240
Spi Axe : 2.0°
Rotation : 30°
Source position found : (-1.678°, 1.005°)
Flux : 0.44 (arbitrary unit)
Pointing number : 241
Spi Axe : 4.0°
Rotation : 30°
Source position found : (-3.4004°, 1.987°)
Flux : 0.44 (arbitrary unit)
Bruyeres Le Chatel - Calibration Results
