Table of Contents--ISSA Explanatory Supplement

Explanatory Supplement
to the
IRAS Sky Survey Atlas

Table of Contents

Credits | Changes | Table of Contents | Index

  1. INTRODUCTION
    1. General Overview
    2. The IRAS Survey
    3. The IRAS Sky Survey Atlas
    4. Cautionary Notes
      1. Absolute Radiometry
      2. Point Source Photometry
      3. Photometric Errors in Low Latitude Images, ISSA Reject Set
      4. Confirmation of Sources
      5. Solar System Debris
      6. Residual Photon-Induced Responsivity Effects
      7. Calibration Change Due to Improvements in the Accuracy of Detector Solid Angles
      8. Ascending vs. Descending Scans
    5. Processing Caveats
      1. Mosaicking
      2. Saturated Data
      3. Destriper Anomalies
      4. Low Spatial Frequency Artifacts
    6. The IRAS Zodiacal History File
  2. IRAS SKY SURVEY ATLAS OVERVIEW
    1. Changes and Improvements in Atlas
      1. Improvements in Relative Calibration
      2. Zodiacal Foreground Removal to Permit Coaddition
      3. Destripers to Stabilize Detector Baselines
      4. Oversampling to Improve the Representation of Spatial Information
      5. Improved Pointing Information
      6. Particle Radiation Removal
      7. Known Asteroid Removal from the Coadded Image
      8. Full-Sized Detectors
    2. Overview of Calibration
      1. Point Source Calibration Method
      2. Spatial Frequency Response
      3. Detector Effective Solid Angles
      4. Zero Point Calibration
      5. Calibration Limitations for Extended Sources
    3. Product Description
  3. PROCESSING
    1. Time-Ordered Detector Data Improvements
      1. Positional Improvements
      2. Calibration Improvements
        1. Detector Response Function
        2. Zero Point Calibration
        3. Other Calibration Enhancements
      3. Deglitching
    2. Time-Ordered to Position-Ordered Detector Data
    3. Image Production
      1. Empirical Corrections
      2. Zodiacal Foreground Removal
      3. Destriping
        1. Global Destriper Overview
        2. Local Destriper
      4. Image Assembly
    4. Quality Checking
      1. Pre-Production
      2. Production
      3. Post-Production
      4. Types of Anomalies
        1. Data Anomalies
        2. Processing Anomalies
  4. ANALYSIS RESULTS
    1. Analysis Overview
    2. Positional Accuracy
    3. Point Spread Function
    4. Photometric Consistency
      1. Point Sources
      2. Extended Sources
      3. Absolute Photometry
    5. Noise Performance and Sensitivity
      1. Cross-Scan vs. In-Scan Noise
      2. Noise Equivalent Surface Brightness in ISSA
      3. Residual Zodiacal Emission
      4. Quality Estimates From Scan-to-Scan Statistics
    6. ISSA Reject Set Background Analysis
  5. FORMATS FOR THE IRAS SKY SURVEY ATLAS (ISSA)
  6. REFERENCES
  7. ACKNOWLEDGMENTS

INDEX OF TABLES

II. IRAS SKY SURVEY ATLAS OVERVIEW

A.1 Detectors Used in IRAS Sky Survey Atlas Images

B.1 Suggested Correction Factors for Spatial Frequencies Between 6' and 2° at 12 and 25 µm

III. PROCESSING

A.1 Hysteresis Equation

A.2(a) Time Constants, 12 µm

A.2(b) Time Constants, 25 µm

A.2(c) Time Constants, 60 µm

A.2(d) Time Constants, 100 µm

A.3 TFPR Model Parameters

C.1(a) Field-Groups for 12 and 25 µm

C.1(b) Field-Groups for 60 and 100 µm

C.2 ISSA and ISSA Reject Fields Containing Comet Trails

C.3 Planet Positions and Corresponding ISSA and ISSA Reject Fields

D.1(a) Amount of Data Removed in Anomaly Processing (|| > 20°)

D.1(b) Amount of Data Removed in Anomaly Processing of the ISSA Reject Set (|b| < 20°)

D.2 ISSA and ISSA Reject Fields Affected by Saturated Data

IV. ANALYSIS RESULTS

B.1 Point Sources Used in the Position and Photometric Analyses

B.2 Position Difference Statistics

C.1 Point Spread Function Dimensions

D.1 IRAS-DIRBE Transformation

E.1 In-Scan vs. Cross-Scan Noise in ISSA Field 398

E.2 Residual Zodiacal Emission Discontinuities

E.3 Residual Zodiacal Emission Gradients

F.1 Parallel Error Analysis, Pixel Size = 0.5°

F.2 Parallel Error Analysis, Pixel Size = 2.0°

F.3 Perpendicular Error Analysis, Pixel Size = 0.5°

F.4 Perpendicular Error Analysis, Pixel Size = 2.0°

V. FORMATS FOR THE IRAS SKY SURVEY ATLAS (ISSA)

1 A Sample FITS Header for Intensity Images (4 byte format)

2 A Sample FITS Header for Intensity Images (2 byte format)

3 FITS Keywords

APPENDIX A

Center Positions for IRAS Sky Survey Atlas

APPENDIX B

B.1 Filter Kernels

APPENDIX C

C.1 Summary of Pre-Production Anomalies Removed from the ISSA Images

APPENDIX D

D.1 Detectors for which Global Destripe Parameters were Derived

D.2 Relationship between Number of Difference Points and Order of Fit, 12 µm

D.3 Relationship between Number of Difference Points and Order of Fit, 25 µm

D.4 RMS of Intensity Differences as a Function of Iteration

APPENDIX E

E.1 100 µm Gain Errors

E.2 60 µm Gain Errors

APPENDIX F

F.1 Statistics of Correction Factors

F.2 Histogram of Gains

APPENDIX G

G.1 Model Parameter Values and Uncertainties

G.2 Correlation Coefficients Between Model Parameters

APPENDIX H

H.1 Pixel Sizes for ZOHF

H.2 Format of ZOHF Version 3.0

H.3 Gain and Offset of each Version 3.0 Observation Compared to each Version 2.0 Observation

H.4 Histograms of Comparison of ZOHF Positions with the Observation Parameter File

INDEX OF FIGURES


I. INTRODUCTION

B.1 Schematic Drawing of the Orbital Geometry

B.2 Schematic Drawing of the IRAS Focal Plane

II. IRAS SKY SURVEY ATLAS OVERVIEW

B.1(a) Plots of IRAS detector response vs. dwell time, 12 and 25 µm

B.1(b) Plots of IRAS detector response vs. dwell time, 60 µm

B.1(c) Plots of IRAS detector response vs. dwell time, 100 µm

C.1 ISSA Fields for ||> 50° in Equatorial Coordinates

C.2 ISSA Fields for ||> 20° in Equatorial Coordinates

C.3 ISSA Fields for ||<20° in Equatorial Coordinates

III. PROCESSING

A.1 Point Source Hysteresis Comparison - 100 µm

C.1(a) Field-Group Boundaries for 12 and 25 µm Local Destriper Processing

C.1(b) Field-Group Boundaries for 60 and 100 µm Local Destriper Processing

C.2 Known Comet Trails as Seen by IRAS

D.1 Distribution of Focal Plane Anomalies

D.2 Distribution of Mini-Streak and Detector-Streak Anomalies

D.3 Distribution of Local Destripe Anomalies for ||>50°

D.4 Occurrence of Saturated Data for Entire Sky

IV. ANALYSIS RESULTS

B.1(a) Histograms of Position Differences in RA Between PSC and ISSA

B.1(b) Histograms of Position Differences in DEC Between PSC and ISSA

C.1(a) Contour Plot of Point Spread Function for a 12 µm Source

C.1(b) Contour Plot of Point Spread Function for a 25 µm Source

C.1(c) Contour Plot of Point Spread Function for a 60 µm Source

C.1(d) Contour Plot of Point Spread Function for a 100 µm Source

D.1 Scatter Plots of PSC vs. ISSA Point Source Fluxes

D.2 Flux Density vs. Aperture Diameter

APPENDIX D

D.1 Distribution of boresight intercepts for the focal plane crossings

D.2 Histogram of boresight crossing counts per fractional scan segment

D.3 Proliferation of detector intercepts - 100 µm

D.4(a) Intensity residuals (HCON-1 and HCON-2) at 12 µm

D.4(b) Intensity residuals (HCON-3) at 12 µm

D.5(a) Intensity differences along a single detector-scan track with a sixth order fit

D.5(b) Intensity differences along a single detector-scan track with a fit derived with the dual-hemisphere-with-overlap algorithm

D.6 Plot of points rejected by the global destriper for detector 42 (25 µm)

D.7 Intensity differences along a detector-scan track illustrating a class IA anomaly

D.8 Intensity differences along a detector-scan track illustrating a class IB anomaly

D.9 Intensity differences along a detector-scan track illustrating a class III anomaly

D.10 Scan segments that have close extreme point pairs for 100 µm fits

APPENDIX F

F.1(a) Gain and offset corrections versus elongation and SOP, 12 µm

F.1(b) Gain and offset corrections versus elongation and SOP, 25 µm

F.1(c) Gain and offset corrections versus elongation and SOP, 60 µm

APPENDIX G

G.1 ZIP data showing zodiacal brightness as a function of solar elongation

G.2 The scanning geometry of the IRAS satellite

G.3 The IRAS bandpasses and a 200 K blackbody

G.4 A typical IRAS pole-to-pole scan with the zodiacal dust cloud model fit

G.5 Data and zodiacal dust cloud model prediction for a scan at solar elongation of 112°

G.6 Data and zodiacal dust cloud model prediction for a scan at solar elongation of 67°

APPENDIX H

H.1 Flux ratio at NEP vs. time from SAA crossing

H.2 Mean flux ratios at NEP and population standard deviations vs. time from SAA crossing