1. ISOCAM Parallel Survey
The 6.7m Point-Source Catalogue
Duilio Farina
Supervisor: Stephan Ott
September 8, 2008

2. ISO ISO Instruments: ISOPHOT, SWS, LWS and ISOCAM
ISOCAM: a camera consisted in a SW (2.5-5m) detector and a LW (4-18m) detector of 32x32 pixel
Prime Survey was performed when ISOCAM was the prime instrument
Parallel Survey was performed in the so-called Paralled Mode when one of the other three instruments observed a target

3. ISOCAM Parallel Survey
Configuration:
LW2: 6.7m
PFOV: 6’’
Time:
3971 hours
24036 pointings

4. Difference between Prime and Parallel
Reduced telemetry rate, the 50% of the Parallel pointings have less than 10 images.
For the majority of Parallel-mode data there is no spatial redudancy.
Sources are distributed all over the detector
PRIME
In Prime there are typically more than 12 images per pointing
Prime surveys were performed in raster observations
The target was generally centered at the middle of the detector
Prime observations were quality checked by ISOCAM Instrument Dedicated Team

5. 1. Type Classification
A list of 207 sources observed in Prime Mode and in Parallel Mode
Type Classification:
Point
Many
Extended
Cloud

6. 2. Match
Example of Bad Match
Example of Good Match

7. 3. Photometry
Manual Photometry was performed for all 207 sources in Prime and in Parallel
Total: 414 sources with manual photometry

8. 1. Results: Auto Vs Manual
Relative Error:
Only Point Sources
Only sources with good match
Only sources far from the edge and the dark column at least 1 pixel
Remaining sources: 95

9. PRIME PARALLEL Total: 95 Rel Err Mean: 0.030 Rel Err RMS: 0.264

10. 2. Results: Prime and Parallel with same configuration
Sources viewed with the same setting in Prime and in Parallel (LW2 and PFOV 6’’) have to give the same flux
We selected:
Point sources
Good match
Far from the edge and dark column at least 1 pixel
Num
Mean
RMS
XPHOT 16
0.011
0.140
AUTO
-0.032
0.170

11. Conclusion
Good agreement between Prime flux and Parallel flux with the same settings
Good agreement between Auto flux and Manual flux in both modes
Parallel Mode is consistent with the Prime Mode

12. Comparison between IPSC and other catalogues
The ISOCAM Point Source Catalogue consist of individual sources with a flux range between 0.48 mJy and 1960 mJy with a median of 3.84 mJy
Comparison with bands: J, H, K (2MASS), B and V (other catalogues) using the Kurucz’s model
We selected 2041 sources:
No indication of source confusion
Number of frame > 10
No other ISO sources in a radius of 25’’
No other 2MASS sources in a radius of 25’’
The five fluxes (B, V, J, H, K) and the filter type are available for 224 of the 2041 sources

13. An example: J H K V
Cam Par B

14. Results Relative Error: Tot: 224 Mean: -0.07 RMS: 0.16
On average the ISOCAM fluxes are lower of about the 7% compared to the Kurucz interpolation

15. Comparison between IPSC and Spitzer
In Spitzer catalogue there are 2618 matches with ISOCAM Point Source Catalogue
We considered only sources with a match in a radius < 2’’ and with good quality flags in Spitzer
Remaining Sources : 1395
2’’

16. An example
IR1 K
IR2
IR3
IR4 H
Cam Par J

17. Results Tot: 1395 Mean: -0.020 RMS: 0.28
Positive outliers due to the better Spitzer’s spatial resolution

18. With cut:
Mean: -0.5
RMS:
On average the ISOCAM fluxes are lower of about the 5% compared to the Spitzer interpolation

19. Future Complete the comparison with Spitzer:
Interpolation with the Kurucz’s model
Delete the multiple matches of Spitzer
Investigate the possibles reasons of the low fluxes of ISOCAM
Check if there is this negative shift also in the Prime observations
Continue to perform the manual photometry:
For the moment we have about 2000 sources with manual photometry