Photometric Calibration

Jorge F. García Yus

GEMINI Observatory

Barolo 2001

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

Cont….

Photographic plate material and filters: IIIaJ+GG385, IIIaF+RG610, IIIaJ+GG395, IIIaF+OG590……

Scanning and digitalization: GAMMA 1 and GAMMA 2, laser and white light

Pipeline data processing: SKYPROCESSOR INVENTORY DEBLENDER FINDCAT PHOTOSOL APPLY_CALYB

GSC 2 Photometric Calibration: from GSH files

S (blue suthern survey)

0

5

10

15

20

25

30

35

40

45

50

10 50 90 130

170

210

250

290

330

370

410

450

490

530

570

610

650

690

730

770

810

850

890

930

970

Number of calibrators

Number of calibrators per field

ER (red southern survey)

0

10

20

30

40

50

60

70

80

10 50 90 130

170

210

250

290

330

370

410

450

490

530

570

610

650

690

730

770

810

850

890

930

970

Number of calibrators

Statistic are over estimated by known problems.Stars with more than one color, calibrators with poor astrometry and multiple observations.

XJ (blue northern survey)

0

5

10

15

20

25

30

35

40

45

10 50 90 130

170

210

250

290

330

370

410

450

490

530

570

610

650

690

730

770

810

850

890

930

970

Number of calibrators

Inconsistence in early reference catalogs version.

XP (red northern survey)

0

10

20

30

40

50

60

10 50 90 130

170

210

250

290

330

370

410

450

490

530

570

610

650

690

730

770

810

850

890

930

970

Number of calibrators

UKST southern hemisphere material: IIIaJ+GG395 (blue) and IIIaF+OG590 (red)

S plates

0

50

100

150

200

250

12.25 12.75 13.25 13.75 14.25 14.75 15.25 15.75 16.25 16.75 17.25 17.75 18.25 18.75 19.25 19.75 20.25 20.75 21.25 21.75

magnitude limit

ER(XS) plates

0

20

40

60

80

100

120

140

160

180

200

12.25 12.75 13.25 13.75 14.25 14.75 15.25 15.75 16.25 16.75 17.25 17.75 18.25 18.75 19.25 19.75 20.25 20.75 21.25 21.75

magnitude limit

POSS-II northern hemisphere material: IIIaJ+GG385 (blue) and IIIaF+RG610 (red)

XJ plates

0

50

100

150

200

250

300

12.25 12.75 13.25 13.75 14.25 14.75 15.25 15.75 16.25 16.75 17.25 17.75 18.25 18.75 19.25 19.75 20.25 20.75 21.25 21.75

magnitude limit

XP plates

0

50

100

150

200

250

12.25 12.75 13.25 13.75 14.25 14.75 15.25 15.75 16.25 16.75 17.25 17.75 18.25 18.75 19.25 19.75 20.25 20.75 21.25 21.75

magnitude limit

POSS-II special constrains: location of original photometric calibrators are vignetted

XJ plates

0

50

100

150

200

250

300

350

400

450

500

0.125 0.375 0.625 0.875 1.125 1.375 1.625 1.875 2.125 2.375 2.625 2.875 3.125 3.375

distance from the center (deg)

XP plates

0

50

100

150

200

250

300

350

400

0.125 0.375 0.625 0.875 1.125 1.375 1.625 1.875 2.125 2.375 2.625 2.875 3.125 3.375

distance from the center (deg)

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

Faint Art. #s #cal dis err Plate Date Comment19.5 19.6 3 805 0.7 0.10 XJ005 7-JAN-200018.7 18.7 4 855 0.6 0.11 XP005 23-NOV-199919.8 19.7 1 578 0.1 0.11 XJ007 19-DEC-200019.1 18.7 1 406 0.1 0.13 XP007 7-JAN-200017.2 16.9 1 515 0.2 0.11 XJ016 7-JAN-2000 No faint GSPC216.2 15.9 1 541 0.2 0.13 XP016 7-JAN-2000 No faint GSPC217.1 16.8 1 413 0.1 0.09 XJ017 20-DEC-1999 No faint GSPC217.7 17.5 2 293 0.1 0.13 XP017 14-OCT-1999 No faint GSPC219.8 19.8 1 404 0.3 0.10 XJ020 7-JAN-200018.5 18.4 1 424 0.3 0.13 XP020 7-JAN-200020.8 20.7 3 699 0.2 0.17 XJ057 20-DEC-199918.6 18.7 3 806 0.1 0.13 XP057 17-JAN-200020.2 20.1 1 698 0.2 0.15 XJ074 6-SEP-200010.9 11.3 1 86 0.0 0.14 XP074 1-NOV-1999 No GSPC220.6 20.7 1 627 0.0 0.11 XJ219 19-DEC-200019.8 19.9 1 356 0.1 0.11 XP219 18-JUL-200121.0 21.2 3 958 2.5 0.15 XJ288 28-OCT-199917.4 17.2 2 77 0.3 0.18 XP288 27-DEC-2000 No faint GSPC219.2 19.3 6 775 0.1 0.12 XJ340 8-MAR-2000 low galactic latitude17.6 17.5 0 1174 0.0 0.19 XP340 21-JUN-2000 No faint GSPC220.3 20.5 1 280 1.2 0.18 XJ428 6-JAN-200019.7 19.7 1 504 1.0 0.14 XP428 6-DEC-199920.4 20.2 4 675 0.1 0.10 XJ493 23-AUG-200019.2 19.3 2 610 0.0 0.11 XP493 20-OCT-199920.8 20.8 2 324 0.2 0.10 XJ533 7-JAN-200018.7 18.7 2 272 0.3 0.13 XP533 7-DEC-199920.3 20.4 1 166 0.4 0.11 XJ599 11-JAN-200018.4 18.3 1 177 0.4 0.12 XP599 16-JAN-200118.4 18.1 2 134 0.2 0.08 XJ653 1-FEB-200017.4 17.2 2 150 0.2 0.12 XP653 16-DEC-1999 No faint GSPC220.0 20.0 1 195 0.4 0.12 XJ660 6-JAN-200011.6 11.8 0 132 0.0 0.16 XP660 16-DEC-1999 No GSPC220.7 20.6 2 246 1.3 0.16 XJ669 7-JAN-200019.0 18.8 1 201 1.9 0.12 XP669 2-DEC-200020.2 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-199919.4 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-2000

Faint Art. #s #cal dis err Plate Date Comment20.6 20.7 1 402 0.2 0.16 XJ847 7-FEB-200020.2 20.1 1 328 0.3 0.15 XP847 22-NOV-199920.9 21.0 1 97 0.5 0.10 XJ880 14-JAN-200119.8 19.8 1 71 0.0 0.15 XP880 11-NOV-199919.9 19.8 2 272 0.3 0.13 XS016 12-JAN-200020.8 20.4 1 579 0.0 0.13 S016 30-JAN-200119.8 19.6 1 432 0.1 0.15 XS162 10-DEC-199921.0 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-199920.8 20.4 2 492 0.0 0.19 S192 20-SEP-200019.6 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-199921.1 20.9 9 206 0.1 0.15 S430 15-NOV-1999 No red plate20.6 20.5 1 914 0.1 0.17 S452 5-OCT-2000 No red plate16.9 16.7 3 155 0.3 0.13 XS468 11-DEC-1999 No faint GSPC217.9 17.3 3 473 0.1 0.11 S468 21-SEP-2000 No faint GSPC217.4 17.6 6 679 0.0 0.27 S522 1-DEC-1999 * large error20.1 20.1 1 981 0.1 0.16 ER633 2-FEB-2001 bad matching?20.9 21.2 1 603 0.1 0.11 S633 29-NOV-200018.1 17.8 2 194 0.4 0.19 ER703 6-FEB-200118.8 18.9 1 823 0.2 0.12 S703 28-NOV-2000 bad matching?20.3 20.5 2 1417 0.1 0.15 ER774 12-FEB-2001 bad matching?21.0 21.1 2 818 0.2 0.13 S774 4-JAN-2001 bad matching?

Star completeness for 1606 pair of plates

Completeness for Star type objects

0

5

10

15

20

25

30

35

40

16.15 16.45 16.75 17.05 17.35 17.65 17.95 18.25 18.55 18.85

F magnitude

% of fields

All object completeness for 1606 pair of plates

Completness for all objects

0

5

10

15

20

25

30

16.15 16.45 16.75 17.05 17.35 17.65 17.95 18.25 18.55 18.85

F magnitude

% of fields

J - F color

13 < F < 14

-1.5

-1

-0.5

0

0.5

1

1.5

2

2.5

3

-100 -80 -60 -40 -20 0 20 40 60 80 100

Galactic latitude

J - F color

14 < F < 15

-1.5

-1

-0.5

0

0.5

1

1.5

2

2.5

3

-100 -80 -60 -40 -20 0 20 40 60 80 100

Galactic latitude

J - F color

15 < F < 16

-1.5

-1

-0.5

0

0.5

1

1.5

2

2.5

3

-100 -80 -60 -40 -20 0 20 40 60 80 100

Galactic latitude

J - F color

16 < F < 17

-1.5

-1

-0.5

0

0.5

1

1.5

2

2.5

3

-100 -80 -60 -40 -20 0 20 40 60 80 100

Galactic latitude

J - F color

17 < F < 18

-1.5

-1

-0.5

0

0.5

1

1.5

2

2.5

3

-100 -80 -60 -40 -20 0 20 40 60 80 100

Galactic latitude

GSC 2 color distribution as a galactic latitude function

Stellar in red and non stellar in blue

-2

-1

0

1

2

3

4

-100 -80 -60 -40 -20 0 20 40 60 80 100

Galactic latitude

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…