1. The aXe slitless extraction software
Designed to extract ACS slitless data
Semiautomatic reduction system (based on object catalogues)
Embedded into STSDAS via PyRAF
First release in 2002
aXe is successfully utilized by many groups
aXe was adapted for various kinds of data:
La Silla 2.2m WFI slitless data
FORS MXU data
NICMOS slitless data
4. May 2006
Martin Kümmel
HLA coordination meeting

2. Examples of data reduced with aXe
ACS
FORS MXU
NICMOS
2.2m WFI
4. May 2006
Martin Kümmel
HLA coordination meeting

3. HLA coordination meeting
The structure of aXe
2: PyRAF/IRAF
interface
1D-extraction
flatfielding
make stamp
background
wavelength calibration
locate object
mark spectrum
1: High Level Tasks
sex2gol
gol2af
backest
af2pet
petff
pet2spc
stamps
axeprep
axecore
aXe_SEX2GOL
aXe_GOL2AF
aXe_BE
aXe_AF2PET
aXe_PETFF
aXe_PET2SPC
aXe_STAMPS
3: C-program
Schematic view on part of aXe tasks:
- C programs work on the pixels
- PyRAF/IRAF interface to integrate them into
the usual data reduction environment
- High Level Task to comprise the individual tasks
work on image lists. Reduce the numbe rof tasks
4. May 2006
Martin Kümmel
HLA coordination meeting

4. HLA coordination meeting
Other ingredients
Calibration inputs:
Auxiliary software:
aXe configuration file
Flatfield
Sensitivity file
Intrapixel correction function
SExtractor for object finding
MultiDrizzle for large, dithered fields
4. May 2006
Martin Kümmel
HLA coordination meeting

5. The aXe configuration file
INSTRUMENT NICMOS
CAMERA NIC3
# Cycle 11 NCS calibration
# September 2002
SCIENCE_EXT SCI ; Science extension
DQ_EXT DQ ; DQ extension
ERRORS_EXT ERR ; Error extension
FFNAME nicmos_flat.fits
DQMASK
DQMASK 256
EXPTIME EXPTIME
DRZRESOLA
DRZSCALE 0.20
DRZLAMB0 1.0
DRZXINI
DRZROOT aXedrizzle
# First order (BEAM A)
BEAMA
MMAG_EXTRACT_A 21
MMAG_MARK_A 24
# Trace description, 1st order
DYDX_ORDER_A 1
DYDX_A_0 0.0
DYDX_A_
# X and Y Offsets
XOFF_A 0.0
YOFF_A -6.8
# Dispersion solution, 1st order
DISP_ORDER_A 2DLDP_A_
DLDP_A_
DLDP_A_2 0.0# Old My rev
SENSITIVITY_A NICMOS.G141.1st.sens.new.fits
General information
Trace information
Spectral information
4. May 2006
Martin Kümmel
HLA coordination meeting

6. Example of a spectral extraction
input
intermediate steps
result
direct image
backgr. subtr.
stamp image
grism image
local backgr.
extracted spectrum
4. May 2006
Martin Kümmel
HLA coordination meeting

7. 2D spectral rebinning with aXedrizzle
10”
extract stamp
coadd
4. May 2006
Martin Kümmel
HLA coordination meeting