Photometric Calibration

1
Photometric Calibration

• Jorge F. García Yus
• GEMINI Observatory
• Barolo 2001

2
GSC-II Photometric Calibration

• Calibrators
• GSPC-I
• B, V magnitudes and brighter than 15th
• TYCHO
• BTycho, VTycho magnitudes and brighter than
  11.5th
• GSPC-II
• B, V, R magnitudes and fainter as 20th
• Color transformations
• One pair for each pass band available
• Range of validate

3
Cont.

• Photographic plate material and filters
• IIIaJGG385, IIIaFRG610, IIIaJGG395,
  IIIaFOG590
• Scanning and digitalization
• GAMMA 1 and GAMMA 2, laser and white light
• Pipeline data processing
• SKYPROCESSOR
• INVENTORY
• DEBLENDER
• FINDCAT
• PHOTOSOL
• APPLY_CALYB

4
GSC 2 Photometric Calibration from GSH files
5
Number of calibrators per field
6
Statistic are over estimated by known
problems.Stars with more than one color,
calibrators with poor astrometry and multiple
observations.
7
Inconsistence in early reference catalogs version.
8
UKST southern hemisphere material IIIaJGG395
(blue) and IIIaFOG590 (red)
9
POSS-II northern hemisphere material IIIaJGG385
(blue) and IIIaFRG610 (red)
10
POSS-II special constrains location of original
photometric calibrators are vignetted
11
GSC 2.2.01 data photometric analyze

• From 1715 square degrees (full sky coverage)
• Rejected 77 southern fields where J magnitude are
  not present (/- 10 galactic latitude, SMC and
  LMC) 5
• Founded and rejected 32, plates with suspicious
  photometry. (mainly large color residuals)
• Total for analyze 1606 plates or 1606 square
  degrees

12
Faint Art. s cal dis err Plate Date Comment 19.5
19.6 3 805 0.7 0.10 XJ005 7-JAN-2000 18.7 18.7 4
855 0.6 0.11 XP005 23-NOV-1999 19.8 19.7 1 578 0.1
0.11 XJ007 19-DEC-2000 19.1 18.7 1 406 0.1 0.13 X
P007 7-JAN-2000 17.2 16.9 1 515 0.2 0.11 XJ016 7-J
AN-2000 No faint GSPC2 16.2 15.9 1 541 0.2 0.13 XP
016 7-JAN-2000 No faint GSPC2 17.1 16.8 1 413 0.1
0.09 XJ017 20-DEC-1999 No faint
GSPC2 17.7 17.5 2 293 0.1 0.13 XP017 14-OCT-1999 N
o faint GSPC2 19.8 19.8 1 404 0.3 0.10 XJ020 7-JAN
-2000 18.5 18.4 1 424 0.3 0.13 XP020 7-JAN-2000 20
.8 20.7 3 699 0.2 0.17 XJ057 20-DEC-1999 18.6 18.7
3 806 0.1 0.13 XP057 17-JAN-2000 20.2 20.1 1 698
0.2 0.15 XJ074 6-SEP-2000 10.9 11.3 1 86 0.0 0.14
XP074 1-NOV-1999 No GSPC2 20.6 20.7 1 627 0.0 0.11
XJ219 19-DEC-2000 19.8 19.9 1 356 0.1 0.11 XP219
18-JUL-2001 21.0 21.2 3 958 2.5 0.15 XJ288 28-OCT-
1999 17.4 17.2 2 77 0.3 0.18 XP288 27-DEC-2000 No
faint GSPC2 19.2 19.3 6 775 0.1 0.12 XJ340 8-MAR-2
000 low galactic latitude 17.6 17.5 0 1174 0.0 0.1
9 XP340 21-JUN-2000 No faint GSPC2 20.3 20.5 1 280
1.2 0.18 XJ428 6-JAN-2000 19.7 19.7 1 504 1.0 0.1
4 XP428 6-DEC-1999 20.4 20.2 4 675 0.1 0.10 XJ493
23-AUG-2000 19.2 19.3 2 610 0.0 0.11 XP493 20-OCT-
1999 20.8 20.8 2 324 0.2 0.10 XJ533 7-JAN-2000 18.
7 18.7 2 272 0.3 0.13 XP533 7-DEC-1999 20.3 20.4 1
166 0.4 0.11 XJ599 11-JAN-2000 18.4 18.3 1 177 0.
4 0.12 XP599 16-JAN-2001 18.4 18.1 2 134 0.2 0.08
XJ653 1-FEB-2000 17.4 17.2 2 150 0.2 0.12 XP653 16
-DEC-1999 No faint GSPC2 20.0 20.0 1 195 0.4 0.12
XJ660 6-JAN-2000 11.6 11.8 0 132 0.0 0.16 XP660 16
-DEC-1999 No GSPC2 20.7 20.6 2 246 1.3 0.16 XJ669
7-JAN-2000 19.0 18.8 1 201 1.9 0.12 XP669 2-DEC-20
00 20.2 20.1 5 2021 0.4 0.12 XJ701 18-DEC-2000 bad
matching? 17.9 17.7 1 762 0.7 0.08 XP701 28-OCT-1
999 19.4 19.2 1 1181 0.1 0.10 XJ773 5-OCT-2000 bad
matching? 18.4 18.4 2 209 0.6 0.13 XP773 24-JAN-2
000
13
Faint Art. s cal dis err Plate Date Comment 20.6
20.7 1 402 0.2 0.16 XJ847 7-FEB-2000 20.2 20.1 1
328 0.3 0.15 XP847 22-NOV-1999 20.9 21.0 1 97 0.5
0.10 XJ880 14-JAN-2001 19.8 19.8 1 71 0.0 0.15 XP8
80 11-NOV-1999 19.9 19.8 2 272 0.3 0.13 XS016 12-J
AN-2000 20.8 20.4 1 579 0.0 0.13 S016 30-JAN-2001
19.8 19.6 1 432 0.1 0.15 XS162 10-DEC-1999 21.0 21
.1 1 1003 0.1 0.16 S162 21-DEC-2000 bad
matching? 20.1 19.9 1 260 0.2 0.12 XS192 10-DEC-19
99 20.8 20.4 2 492 0.0 0.19 S192 20-SEP-2000 19.6
19.5 2 1485 0.1 0.14 XS372 6-FEB-2001 bad
matching? 18.1 17.8 1 137 0.0 0.17 S372 8-SEP-1999
21.1 20.9 9 206 0.1 0.15 S430 15-NOV-1999 No red
plate 20.6 20.5 1 914 0.1 0.17 S452 5-OCT-2000 No
red plate 16.9 16.7 3 155 0.3 0.13 XS468 11-DEC-19
99 No faint GSPC2 17.9 17.3 3 473 0.1 0.11 S468 21
-SEP-2000 No faint GSPC2 17.4 17.6 6 679 0.0 0.27
S522 1-DEC-1999 large error 20.1 20.1 1 981 0.1
0.16 ER633 2-FEB-2001 bad matching? 20.9 21.2 1 60
3 0.1 0.11 S633 29-NOV-2000 18.1 17.8 2 194 0.4 0.
19 ER703 6-FEB-2001 18.8 18.9 1 823 0.2 0.12 S703
28-NOV-2000 bad matching? 20.3 20.5 2 1417 0.1 0.1
5 ER774 12-FEB-2001 bad matching? 21.0 21.1 2 818
0.2 0.13 S774 4-JAN-2001 bad matching?
14
Star completeness for 1606 pair of plates
15
All object completeness for 1606 pair of plates
16
J - F color
17
J - F color
18
J - F color
19
J - F color
20
J - F color
21
GSC 2 color distribution as a galactic latitude
function
22
Conclusions

• GSC 2.2.01 provide at least 1 calibrated star
  (photometrical (J,F) and astrometrical) in a
  2.5x2.5 minute squares. Dense enough for the
  telescope operation
• The number of fields that need photometric
  recalibration are less than 5
• The major effort for the next release will be
  improving the accuracy for the faint end,
  providing an even product with a very good data
  quality for astrophysical research
• An effort still needs is in the pass band
  characterization, specially oriented for the
  final users (Observing tools, proposals planning,
  etc.) .may be my homework