IRAC Instrument Handbook - IRSA - California Institute of Technology

List of Figures 193
IRAC Instrument Handbook
FIGURE 7.8: MEDIAN OF CHANNEL 1 IMAGES FROM A CALIBRATION OBSERVATION
PERFORMED AFTER OBSERVING POLARIS. THE 5 BRIGHT SPOTS ARE PERSISTENT
IMAGES FROM STARING AT THE STAR WHILE OBSERVING, WHILE THE SET OF CRISS-
CROSSING LINES WERE GENERATED BY SLEWS BETWEEN THE VARIOUS POINTINGS.
THESE OBSERVATIONS WERE TAKEN FROM AORKEY=3835904, IN PROGRAM PID=19.
.............................................................................................................................................. 117
FIGURE 7.9: RESIDUAL IMAGE BRIGHTNESS DECAY AS A FUNCTION OF TIME INTERVAL
SINCE EXPOSURE TO A FIRST MAGNITUDE SOURCE AT 3.6 ΜM. THE RESIDUAL IS
COMPARED TO THREE TIMES THE NOISE IN THE SKY BACKGROUND AS MEASURED
IN AN EQUIVALENT APERTURE. THE FITTED EXPONENTIAL DECAY FUNCTION IS
PLOTTED AS THE DOT-DASHED LINE. THESE CURVES HAVE BEEN SMOOTHED TO
MITIGATE FLUX JUMPS DUE TO SOURCES AT THE POSITION OF THE ORIGINAL
SOURCE IN SUBSEQUENT IMAGES. .................................................................................. 119
FIGURE 7.10: AN IMAGE OF THE M51 SYSTEM, SHOWING AN OVERLAY OF THE IRAC
FIELDS OF VIEW, WITH THE SCATTERED LIGHT ORIGIN ZONES FOR CHANNELS 1 AND
2 OVERLAID. ........................................................................................................................ 120
FIGURE 7.11: CHANNEL 1 IMAGE SHOWING SCATTERED LIGHT ON BOTH SIDES OF A
BRIGHT STAR. THE SCATTERED LIGHT PATCHES ARE MARKED WITH WHITE “S"
LETTERS. THE IMAGES WERE TAKEN FROM PROGRAM PID 30 DATA. ........................ 121
FIGURE 7.12: CHANNEL 2 IMAGE SHOWING SCATTERED LIGHT ON ONE SIDE OF A BRIGHT
STAR. THE SCATTERED LIGHT PATCHES ARE MARKED WITH WHITE “S" LETTERS.
THE IMAGES WERE TAKEN FROM PROGRAM PID 30 DATA. .......................................... 122
FIGURE 7.13: CHANNEL 3 IMAGE SHOWING SCATTERED LIGHT FROM A SCATTERING
STRIP AROUND THE EDGE OF THE ARRAY WHERE A BRIGHT STAR IS LOCATED. THE
SCATTERED LIGHT PATCHES ARE MARKED WITH WHITE “S" LETTERS. THE IMAGES
WERE TAKEN FROM PROGRAM PID 30 DATA. ................................................................. 123
FIGURE 7.14: CHANNEL 4 IMAGES SHOWING SCATTERED LIGHT FROM A SCATTERING
STRIP AROUND THE EDGE OF THE ARRAY WHERE A BRIGHT STAR IS LOCATED. THE
SCATTERED LIGHT PATCHES ARE POINTED TO BY BLACK ARROWS. THE IMAGES
WERE TAKEN FROM PROGRAM PID 30 DATA. ................................................................. 124
FIGURE 7.15: TYPICAL IMAGE SECTIONS SHOWING THE BANDING EFFECT. THESE ARE
CHANNEL 3 (LEFT) AND CHANNEL 4 (RIGHT) IMAGES OF THE SAME OBJECT (S140),
ADOPTED FROM A REPORT BY R. GUTERMUTH. THESE DATA WERE TAKEN FROM
PROGRAM PID 1046, AORKEY 6624768. ............................................................................. 125
FIGURE 7.16: FILTER AND BEAMSPLITTER GHOSTS. ............................................................. 127
FIGURE 7.17: PUPIL GHOST IN CHANNEL 2 FROM V416 LAC. ................................................ 128
FIGURE 7.18: PART OF THE CHANNEL 1 MOSAIC (FROM OBSERVATIONS IN PID 181;
AORKEYS 5838336, 5838592, 5839872 AND 5840128) OF THE SWIRE FIELD NEAR MIRA
SHOWING THE 24 ARCMINUTE RADIUS RING OF STRAY LIGHT FROM THE
TELESCOPE. ......................................................................................................................... 129
FIGURE 7.19: CHANNEL 2 IMAGES FROM THE SWIRE MAP SHOWING STRAY LIGHT
SPLOTCHES FROM MIRA, WHICH WAS ABOUT 30 ARCMINUTES AWAY. SUCCESSIVE
PAIRS OF IMAGES WERE SLIGHTLY DITHERED. THE LAST PAIR IS ABOUT 5
ARCMINUTES FROM THE FIRST PAIR, BUT HAS A SIMILAR SPLOTCH. NOTE THE