1. UVIS Team – Meeting
H. Uwe Keller, Yuri Skorov, Ralf Reulke

2. HDAC Progress We worked on two major topics
Corrections of signal contributions by background stars
Comparison of Lyman Alpha observations with FUV
Both topics work in progress

3. Hot Background Stars Use of ESRO TD1 catalog (about 1700 stars)
Extrapolate or estimate relevant part of star spectrum depending on type
Convolute with spectral sensitivity of HDAC
Estimate signal contribution from absolute magnitude of star and position within the HDAC FOV
Good correlation with peaks
However, stars are missiong for some peaks of observed signal and in a few cases vice versa
For detailed comparison with FUV we shall select viewing directions with low number of stars (not in galactic plane)

4. Distribution of UV objects in the sky (ESRO TD1 catalog)

5. Example of obtained preliminary results
HDAC2011_058_21_03_20
Red: HDAC observation
Black: estimated contributions from background stars
HDAC2011_124_06_18_15

6. Comparison with FUV
Goal is to verify calibration of FUV (and HDAC) by cross calibration
First comparison of observations during s/c rotation periods show good agreement
FUV data provided by Greg Holsclaw cover so far samples from 2006 to 2011
In detail view there are small differences
FUV data are more variable than HDAC data
Mostly due to the smaller FOV (slit) of FUV compared to HDAC
Detailed investigations of the star transients will provide information on the sensitivity within the HDAC FOV

7. FUV and HDAC

9. Next UVIS Team Meeting See you in Berlin from 16.-18.06.2014
Social event on Sunday (15. 6.) afternoon
Have a good meeting!