Chandra/CIAO Dictionary
Chandra and CIAO use a number of specialized terms, some of which are common in X-ray astronomy data analysis, but not used elsewhere, and some of which are specific to CIAO.
Here we provide a dictionary of these terms. We have provided links to more information in the CIAO website, on the CXC site in general, and in external webpages as appropriate. Help on the CIAO tools is available from the ahelp documentation page.
- A
- ACIS Background
- ACIS: Advanced Camera for Imaging and Spectroscopy
- ADU
- Afterglow
- Alternating Exposure Mode
- APEC: Astrophysical Plasma Emission Code
- APED: Astrophysical Plasma Emission Database
- AREASCAL
- ARF: Auxiliary Response File
- asol
- Aspect / Aspect Solution
- Aspect Histogram
- ATOMDB: Atomic Database
- B
- BACKSCAL
- Bad Pixels
- BI: Backside Illuminated
- C
- CALDB: Calibration Database
- Chandra
- ChaRT: The Chandra Ray Tracer
- ChIPS: Chandra Image and Plotting System
- CIAO: Chandra Interactive Analysis of Observations
- Continuous Clocking (CC)-mode for ACIS
- Coordinates
- CP: Custom Processing
- CSC: Chandra Source Catalog
- CTI: Charge Transfer Inefficiency
- CXC: Chandra X-ray Center
- D
- Dead Time
- Dither
- DM: Data Model
- ds9
- DTCOR
- DTF
- DTF: Data Text Format
- DTF: the HRC Dead-Time Factor file
- E
- Effective Area
- Energy
- EPHIN: Electron Proton Helium Instrument
- Event
- evt
- EXPOSURE and EXPOSURn
- Exposure Maps
- EXPTIME
- F
- FEF: FITS Embedded Function
- FI: Frontside Illuminated
- FITS: Flexible Image Transport System
- FLSHTIME
- flt
- FOV: Field of View
- FP_TEMP
- G
- Gain
- Grade (Event Grade)
- GTI: Good Time Interval
- GUI
- H
- Hardness Ratio
- HETG: High Energy Transmission Grating
- HRC: High Resolution Camera
- HRMA: High Resolution Mirror Assembly
- I
- img
- Instrument Maps
- Interleaved Mode
- ISIS
- L
- LETG: Low Energy Transmission Grating
- LIVTIMEn and LIVETIME
- LSF: Line Spread Function
- M
- Marx
- Mask File
- MSC coordinate system: Theta and Phi
- mtl / MTL: Mission Time Line
- O
- OBC: On-Board Computer
- OBI: Observation Interval
- Observation Times
- ObsID: Observation Id
- OGIP: Office for Guest Investigator Programs
- OIF: Observation Index File
- ONTIME and ONTIMEn
- osol
- OTS: Off-The-Shelf software
- P
- PCAD: Pointing Control and Aspect Determination
- PHA keywords
- PHA: Pulse Height Amplitude
- PI: Pulse Invariant
- Pileup
- Pitch
- Pixlib
- Platform
- Prism
- PSF: Point Spread Function
- Python
- Q
- QE: Quantum Efficiency
- QEU: Quantum Efficiency Uniformity
- R
- Readout Streak Events
- Regions
- Repro, reprocessing, and reprocessed
- RMF: Redistribution Matrix File
- S
- ACIS Subpixel Event Repositioning
- SDP: Standard Data Processing
- Sherpa
- SIM: Science Instrument Module
- src
- Stacks
- Status Bits
- Streak Events
- Subspace / Data Subspace
- T
- TCD: Transforms, Convolutions and Deconvolutions
- tg_part
- TIMEDEL
- TSTART & TSTOP keywords
- V
- V&V: Verification and Validation
- Virtual Columns
- VTP: Voronoi Tessalation and Percolation
- W
- WCS: World Coordinate System
- WMAP: Weight Map
- X
- X-rays
- Y
- Yaw
- Z
- z
- Zeroth Order