STScI Logo

Hubble Space Telescope
IR Photometric Calibration

Table of Contents

IR photometry is currently based on derived quantities from observations of the three HST white dwarf standard stars,  GD153, G191B2B, GD71, and the G-type star,  P330E,  acquired between 2009 and 2012. Data were reduced with CALWF3 and  processed with AstroDrizzle.The independent calibrations from the four stars agree to within 1% in most filters.  The inverse sensitivity per filter,  PHOTFLAM, is based on the average of the measurements.

The tables below are the derived quantities from observations of GD153, G191B2B, GD71, and P330E acquired between 2009 and 2012. The independent calibrations from the four stars agree to within 1% in most filters, and the photometric zeropoint is set to the average of the measurements. The data sets were processed with AstroDrizzle.

IR Inverse Sensitivity (Zeropoint) Tables:

The 2012 PHOTFLAM values are provided for the infinite aperture (defined as having a radius of 6 arcseconds) and  for an aperture of radius r=0.4 arcseconds (corresponding to a radius of about 3 pixels)

IR values of the inverse sensitivity (photflam) and photometric zeropoints in the STmag, ABmag and VegaMag systems

For the infinite aperture

IR Filter PHOTPLAM PHOTFLAM

r=infinite

PHOTBW STmag ABmag VEGAmag
  Å erg cm-2Å-1 e-1 Å mag mag mag
IR Wide Band Filters
F105W 10552 3.04E-20 845.64 27.6933 26.2687 25.6236
F110W 11534 1.53E-20 1428.5 28.4401 26.8223 26.0628
F125W 12486 2.25E-20 866.28 28.0203 26.2303 25.3293
F140W 13923 1.47E-20 1132.4 28.479 26.4524 25.3761
F160W 15369 1.93E-20 826.28 28.1875 25.9463 24.6949
IR Medium Band Filters
F098M 9864.1 6.05E-20 500.73 26.9456 25.6674 25.1057
F127M 12740 9.33E-20 249.55 26.4749 24.6412 23.6799
F139M 13838 9.18E-20 278.04 26.4926 24.4793 23.4006
F153M 15322 7.60E-20 378.94 26.698 24.4635 23.2098
IR Narrow Band Filters
F126N 12585 4.93E-19 339.32 24.6681 22.8609 21.9396
F128N 12832 4.28E-19 357.45 24.8219 22.9726 21.9355
F130N 13006 4.10E-19 274.17 24.8686 22.99 22.0138
F132N 13188 4.15E-19 319.09 24.856 22.9472 21.9499
F164N 16403 2.78E-19 700.04 25.2915 22.9089 21.5239
F167N 16642 2.58E-19 645.21 25.3707 22.9568 21.5948

For an aperture with radius r=0.4 arcsec

IR FILTER

PHOTPLAM

PHOTFLAM

r=0.4 arcsec

PHOTBW

STmag

ABmag

VEGAmag

 

Å

erg cm-2Å-1 e-1

Å

mag

mag

mag

IR Wide Band Filters

F105W

10552.00

3.55795e-20

845.64

27.5220

26.0974

25.4523

F110W

11534.00

1.8026e-20

1428.50

28.2602

26.6424

25.8829

F125W

12486.00

2.66696e-20

866.28

27.8349

26.0449

25.1439

F140W

13923.00

1.75811e-20

1132.40

28.2874

26.2608

25.1845

F160W

15369.00

2.2988e-20

826.28

27.9963

25.7551

24.5037

IR Medium Band Filters

F098M

9864.10

7.03218e-20

500.73

26.7823

25.5041

24.9424

F127M

12740.00

1.1084e-19

249.55

26.2882

24.4545

23.4932

F139M

13838.00

1.09518e-19

278.04

26.3013

24.2880

23.2093

F153M

15322.00

9.06139e-20

378.94

26.5070

24.2725

23.0188

IR Narrow Band Filters

F126N

12585.00

5.84957e-19

339.32

24.4822

22.6750

21.7537

F128N

12832.00

5.08262e-19

357.45

24.6348

22.7855

21.7484

F130N

13006.00

4.87287e-19

274.17

24.6806

22.8020

21.8258

F132N

13188.00

4.9328e-19

319.09

24.6673

22.7585

21.7612

F164N

16403.00

3.32699e-19

700.04

25.0949

22.7123

21.3273

F167N

16642.00

3.09635e-19

645.21

25.1729

22.7590

21.3970

 

Prior Calibration

Delivery

Calibration

Reference File

CALWF3 version

Description

Change

Documentation                

Dec 10, 2008

Ground Flats

s*pfl.fits

v1.4+

Thermal vacuum data

 

2008-28

Nov 18, 2009

In-flight Zeropoints

(infinite)

   

Polynomial correction with wavelength

GD 153, P330E

FLT*PAM

10-15% higher sensitivity than ground test data

2009-30

Nov 10, 2009

In-flight EE

   

F098M, F105W and F160W

Other filters from optical models

 

2009-37

Dec 7, 2010

In-flight Flats

u*pfl.fits

 

Ground flats corrected by a 'grey' delta-flat

Computed from average sky flat for all filters

+/- 2% correction

2011-11

Mar 06, 2012

Revised Zeropoints

(Infinite and 3 pix)

   

Filter-dependent correction

GD153, GD71, G191B2B, P330E

Master DRZ frames, per filter

 

Available via this WFC3 webpage only: Kalirai et al.

(see above tables)

Nov 19, 2012

First IMPHTTAB for IR

(infinite)

wbj1825ri_imp.fits

v3.1.6+

HSTCAL replaces calls to STSDAS/synphot in calwf3 to populate PHOT keywords

 

HSTCAL Webpage

 

Created 09/09/2009 MJD

Modified 03/06/2012 by CMP

Modified 06/16/2017 by HGK