Fermi Large Area Telescope at ASDC: list of the used acronyms.  

Note: some acronyms in Italian are also included in this list.


    Here you can download this list in a single PDF document.


0FGLFermi LAT Bright Gamma-Ray Source List
1FGLFirst Fermi LAT Gamma-ray Source Catalog
1FHLFirst Fermi LAT Hard Sources List
1LACFirst Fermi LAT AGN Catalog
2FGLSecond Fermi LAT Source Catalog
2LACSecond Fermi LAT AGN Catalog
3CThird Cambridge Radio Catalogue
3EGThird EGRET Catalog
4CFourth Cambridge Radio Catalogue
A&AAstronomy & Astrophysics (scientific journal)
AADAcquisizione e Archiviazione Dati
AAEAstrofisica delle Alte Energie
AASAmerican Astronomical Society
ACAlternating Current
ACAnalysis Coordinator
ACDThe LAT Anticoincidence Detector Subsystem
ACFAutocorrelation Function
ACTAtmospheric Cherenkov Telescope
ADAFAdvection Dominated Accretion Flow
ADCAccretion Disk Corona
ADDAccesso e Distribuzione Dati
ADSAstrophysics Data System
AFSAndrew File System
AGILEAstro-rivelatore Gamma a Immagini Leggero (Light Astro Gamma Image detector)
AGNActive Galactic Nuclei
AISAdvanced Information Systems (General Dynamics)
akaAlso known as
AMSAlpha Magnetic Spectrometer
AOAnnounce of Opportunity
AORAstronomical Observation Request
APhAstroparticle Physics (scientific Journal)
APIDApplication Process ID
ApJThe Astrophysical Journal (scientific journal)
APMAutomatic Plate Measuring machine
APODAstronomy Picture of the Day
ARFAncillary Response File
ARRAutonomous Repointing Request
ASCIIAmerican Standard Code for Information Interchange
ASDAstrophysics Science Division (of GSFC)
ASDCASI Science Data Center
ASEAstrofisica Sorgenti Extragalattiche
ASIAgenzia Spaziale Italiana
ASMAll Sky Monitor (RXTE)
ASOAugust September October 2008 LAT source list
ASPAutomatic Science Processing
ATAcceptance Test
ATelThe Astronomer's Telegram
ATGAllegato Tecnico Gestionale
ATSAbsolute Time Sequence
AUAstronomical Unit
AWAlfvén Waves
AXPAnomalous X-ray Pulsar
BABurst Advocate
BALBroad Absorption Line quasar
BATBurst Alert Telescope (Swift instrument)
BATSEBurst and Transient Source Experiment on CGRO
BBBBig Blue Bump
BBNBig Bang Nucleosynthesis
BBRBlackbody Radiation
BGOBismuth Germanate
BHXRBBlack Hole X-ray Binary
BIOSBasic Input Output System
BL LacBL Lacertae
BLRBroad Line Region
BLRGBroad Line Radio Galaxy
BMBackup Manager
BPLBroken Power Law
BpsBits per second
BRBackground Rejection
BSLBright Source List
BSMBeyond Standard Model
BTBeam Test
BTBrightness Temperature
BWBlast Wave
BZ-Roma multi-frequency catalogue of known blazars
BZPBlandford-Znajek Process
C&ACalibration and Analysis
CALThe LAT Calorimeter Subsystem
CALDBCalibration Database
CalTechCalifornia Institute of Technology
CCBConfiguration Control Board
CCDCharge-coupled Device
CCFCross-correlation Function
CDAFConvection-dominated Accretion Flow
CDMCold Dark Matter
CDRCritical Design Review
CDSCentre de Donné astronomiques de Strasbourg
CEACommissariat a l'Energes Atomique
CENBGCentre d'etudes Nucleaires de Bordeaux Gradignan
CERNCentre European pour la Recherche Nucleaire
CFCosmic Fireball
CFCooling Flow
CGACapitolato Generale ASI
CGROCompton Gamma-ray Observatory
CHIMECosmic ray effects on Micro-electronics
CHSCommanding, Health and Safety
CIBCosmic Infrared Background
CMConfiguration Management
CMB / CMBRCosmic Microwave Background Radiation
CMTConfiguration Management Tool
CNBCosmic Neutrino Background
CNRSCentre National de la Recherche Scientifique
COCarbon Oxygen
COBECosmic Background Explorer
COMPTELCompton Telescope on CGRO
CONConfluence (wiki Jira system at SLAC)
COS-BESA second Celestial Observational Satellite
CPUCentral Processing Unit
CRCosmic Ray
CSACyber Security Awareness
CsI (TI)Cesium Iodide crystal doped with Thallium
CSSCascading Style Sheets
CSSCompact Steep Spectrum sources
CSWCore Software
CTCapitolato Tecnico
CTACherenkov Telescope Array
CTBClassification Tree Bill variables
CTSCoordinatore Team Scientifico
CUCalibration Unit
CVSopen source Concurrent Versions System
CWTContinuous Wavelet Transform
CYCalendar Year
CZTCadmium Zinc Telluride
DADocumento Applicabile
DAFData Archive Facility
DAPNIADépartement d'Astrophysique, de physique des Particules, de physique Nucléaire et de l'Instrumentation Associée
DAQ, EDAQLAT Electronics, Data Acquisition and Flight system
DARDisk Archive
DASDemand Access System
DATData Acquisition Toolkit
DBData Base
DBDoppler Boosting
DCData Catalog
DCData Challenge
DCDirect Current
DCNDocument Change Notice
DDData Downlink
DDDisk Drive
DEDark Energy
DEBRDiffuce Extragalactic Background Radiation
DESData Encryption Standard
DFRelativistic Doppler Factor
DFIData Flow public Interface
DHData Handling
DigiDigitized Event Data
DLDebye Length
DMData Mining
DMData Monitoring
DMDark Matter
DMNPDark Matter and New Physics
DOEDepartment of Energy
DPData Processing
DPDoppler Boosting
DPUData Processing Unit
DQData Quality
DQMData Quality Monitor
DRDocumento di Riferimento
DRMNGBDouble precision Reverse communication routine that Minimize General simply Bounded objective function
DRPData Release Plan
DCData Stream
DSDuty Scientist
DSADiffusive Shock Aceleration
DSMCData Services Management Center
DTRData Transmission Request
DWTDiscrete Wavelet Transform
DXRBSDeep X-Ray Blazar Survey
EAEffective Area
EBLExtragalactic Background Light
ECEvent Class
ECEuropean Commission
EC External Compton
ECCExternal Compton from Clouds
ECDExternal Compton from Disk
ECEError Circle Explorer
EDEvent Data
EEError Ellipse
EEDElectron Energy Distribution
EGRBExtragalactic Gamma-Ray Background
EGRETEnergetic Gamma Ray Experiment Telescope on CGRO
EGSEElectrical/Electronics Ground Support Equipment
EICExternal Induced Compton
ELEddington Limit
ELVExpendable Launch Vehicle
EMSEleven Month Source
EMSSEinstein satellite Medium Sensitivity Survey
ENLRExtended Narrow Line Region
EOSEquation of State
EOSASI Esplorazione e Osservazione dello Spazio
EPO, E/POEducation and Public Outreach
EPUEvent Processing Unit
ERCExternal-jet Radiation Compton
ESAEuropean Space Agency
ESA-RSSDESA Research and Scientific Support Department
ESOEuropean Southern Observatory
ESRINESA European Space Research Institute
ETEEnd to End
EUEngineering Unit
EUEuropean Union
EVOEnabling Virtual Organizations teleconference system
F2FFace to face
FAFlare Advocate
FAMEFlare Advocate Meeting on EVO
FA/GSWFlare Advocate - Gamma-ray Sky Watcher
FAQFrequently Asked Questions
FASFull Approximation Storage algorithm
FDCFermi Data Centre (presso ASDC)
FDSFinite-Difference Scheme
FEMFinite Element Method
FERFermi Gamma-ray Space Telescope
FFflip-flop, bistable, model
FFTFast Fourier Transform
FGLFermi Gamma-ray Space Telescope (Large Area Telescope)
FGSTFermi Gamma-ray Space Telescope (deprecated)
FIRFinal Report
FIRSTFaint Images of the Radio Sky at Twenty centimetres survey
FITSFlexible Image Transport System
FLAMCOGFermi LAT Multiwavelength Coordinating Group
FLOPSFloating point Operations per Second
FOFlight Operations
FOSFlight Operations Software
FOTFlight Operations Team
FOVField of View
FPFramework Programme
FPEFokker-Planck Equation
FRFinal Review
FREDFast Rise Exponential Decay
FREDFox and Ruby Event Display
FSFITS Skimmer
FSRQFlat Spectrum Radio Quasar
FSSCFermi Science Support Center (at GSFC)
FSWFlight Software
FT1/FT2LAT event/spacecraft FITS files
FTEFull Time Equivalent
FTOOLSFITS Tools software
FTPFile Transfer Protocol
FSWFlight Software
fvFITS viewer
FWHMFull Width at Half Maximum
FYFiscal Year
FYIFor your interest
GARCGLAST ACD Readout Controller
GBMGLAST/Fermi Burst Monitor
GbpsGigabits per second
GCGalactic Centre
gccGNU Compiler Collection
GCNGamma-ray Burst Coordinate Network
GCRGalactic Cosmic Ray
GCRCGLAST Calorimeter Read-out Controller - Digital
GDGeneral Dynamics
GEANT4Detector description and simulation tool
GEMGlobal-Trigger Electronics Module
GeVGiga (10^9, billion) electronvolts
GFGreen functions
GGSGalactic Gamma-ray Source
GHGalactic Halo
GIFGraphics Interchange Format
GIOCGBM Instrument Operations Center
GITDGLAST Instrument Technology Development
GLASTGamma-ray Large Area Space Telescope
GLEAMGLAST LAT Event Analysis Machine
GSMGround Mission Segment
GNGround Network
GNUGNU's Not Unix
GOGuest Observer
GOFGuest Observer Facility
GPSGlobal Positioning System
GPSGHz-Peaked Spectrum sources
GPUGraphic Processing Unit
GRGeneral Relativity
GRAPWGNASA Gamma-ray Astronomy Programs Working Group
GRBGamma-Ray Burst
GRIDComputing grid
GROGamma Ray Observatory
GSGround Station
GSGround System
GSEGround Support Equipment
GSFCNASA Goddard Space Flight Center
GTGLAST software Tool
GTIGood Time Interval
GUIGraphic User Interface
GWGravitational Wave
H&SHealth & Safety
HBLHigh Energy peaked BL Lac Objects
HDHard Disk
HDFHierarchical Data Format
HDUHeader and Data Unit
HEHigh Energy
HEALPixHierarchical Equal Area isoLatitude Pixelization of a sphere
HEASARCHigh Energy Astrophysics Science Archive
HEASOFTHigh Energy Astrophysics Software
HEPHigh Energy Physics
HEPAPDOE High Energy Physics Advisory Panel
HEPLW.W. Hansen Experimental Physics Laboratory at Stanford University
HESSHigh Energy Stereoscopic System
HEWHalf Energy Width
HFQPOHigh Frequency Quasi-Periodic Oscillation
HGLHigh Galactic Latitude
HIPHeavy Ion Particle
HK/HSKHouse Keeping
HPDHalf-Power Diameter
HPQHigh Polarized Quasar
HSHot Spot
HSPHigh Synchrotron Peaked
HSTHubble Space Telescope
HW, h/wHardware
I&TIntegration and Test
IACTImaging Atmospheric Cherenkov Telescope
IAUInternational Astronomical Union
IAUCInternational Astronomical Union Circular
IBLIntermediate Energy peaked BL Lac Objects
ICIndex Catalog
ICInverse Compton
ICDInterface Control Document
ICFIntrinsic Correlation Function
ICTInformation Communication Technology
ICUInstrument Control Unit
IDLInteractive Data Language
IDPInstrument Data Processing
IDSInterdisciplinary Scientist
IDVIntraday Variability
IEEEInstitute of Electrical and Electronics Engineers
IGInner Galaxy
IGRINTEGRAL Gamma-Ray source
ILSIntegrated Logistic Support
ILSCInteractive LAT Source Catalog
IMBHIntermediate Mass Black Hole
IN2P3Institut National de Physique Nucleaire et de
INAFIstituto Nazionale di Astrofisica
INFNIstituto Nazionale di Fisica Nucleare
INTEGRALINTErnational Gamma-Ray Astrophysics Laboratory
IOVIn Orbit Validation
IPImage Processing
IPACInfrared Processing and Analysis Center
IPOInput Process Output
IPRIntellectual Property Right
IRFSLAT Instrument Response Functions
ISInstrument Scientist
ISASInstitute for Space and Astronautical Science, Japan
ISBNInternational Standard Book Number
ISMInterstellar Medium
ISOCLAT Instrument Science Operation Center (formerly LIOC or LISOC)
ISPIntermediate Synchrotron Peaked
ISSInternational Space Station
ITInformation Technology
ITOSIntegrated Test and Operations System
JDJulian Date
JIRA(from Gojira) Bug/issue wiki tracking management software
JPEGJoint Photographic Experts Group
JASJava Application Server
JVMJava Virtual Machine
KBAKu-Band Antenna
KBHKerr Black Hole
KbpsKilobits per second
KEKompaneets Equation
KEDKinetic Energy Dominated
KeVKilo (10^3, thousand) electronvolts
KFKalman Filter
KOKick Off
KPKey Project
KSCNASA Kennedy Space Center
KTHRoyal Institute of Technology, Sweden
L&EOLunch and Early Operations
L0/L1/L2Level zero (raw after telemetry), Level one (ready for analysis), Level two (analysis results) data
L0PLevel zero Products
LANLocal Area Network
LANLLos Alamos National Laboratory
LASLAT Astro-Server
LATLarge Area Telescope di Fermi
LATTELAT Test Executive
LBASFermi LAT List of Bright AGN Sources
LBFGSLimited-memory Broyden Fletcher Goldfarb Shanno method
LBGLyman-Break Galaxies
LBLLow energy peaked BL Lac Objects
LCLight Curve
LDCLAT Data Catalog
LDFLAT Data Flow
LDPLAT Data Products
LEOLow Earth Orbit
LFLuminosity Function
LFEPFront-End Processor
LFQPOLow Frequency Quasi-periodic Oscillation
LGLLow Galactic Latitude
LHCLarge Hadron Collider
LHEALaboratory for High Energy Astrophysics at NASA
LHKLAT Housekeeping
LICOSLAT Instrument Checkout System
LISOCLAT Instrument Science Operations Center
LINERLow Ionization Emission Line Region
LIOCLAT Instrument Operations Center (now ISOC )
LIVLorentz Invariance Violation
LLELAT Low Energy data class
LMCLarge Magellanic Cloud
LOFLAT Operations Facility
LPLog Parabola
LPAOutput from Level 1 processing of on-orbit data
LPCLinear Predictive Coding
LPQLow Polarized Quasar
LSALAT Science Analysis
LSFLAT Science Format
LSFLoad Sharing Facility
LSGLAT Collaboration Science Groups
LSPLow Synchrotron Peaked
LSPLomb-Scargle Periodogram
LTLorentz Transformation
LTCLivetime Cube
LUWLAT User Workbook
LYLight Year
µm10^-6 meter
M&SMaterials & Services
MAGICMajor Atmospheric Gamma Imaging Cherenkov
MARMultiple Access Return
Mbps, Mb/sMegabits per second
MCMonte Carlo
MCMarkov Chain
MCCMission Control Center
MCRMobile Computing Rack
MdFMinistero della Difesa
MDOMassive Dark Object
MEMMaximum Entropy Method
METMission Elapsed Time
MeVMega (10^6, million) electronvolt
MGSEMechanical Ground Support Equipment
MILAMeritt Island Launch Annex
MIPMinimally Ionizing Particle
MIURMinistero dell'Istruzione, Università e Ricerca
MITMassachusetts Institute of Technology
MJDModified Julian Date
Mkn / MkrMarkarian
MMIAMulti-Mission Interactive Archive
MNRASMonthly Notices of the Royal Astronomical Society (scientific journal)
MOCMission Operation Center
MoUMemorandum of Understanding
MPMission Planning
MPEMax Planck Institute for Extraterrestrial Physics
MSMerit Skimmer
MSAModular Smart Array
MSFCNASA Marshall Space Flight Center
MSSMission System Specification
MSSMMinimal Supersymmetric Standard Model
MSTMinimum Spanning Tree
MW, MWLMultiwavelenght (i.e. Multifrequency)
NANon Applicable
NaISodium Iodide
NASNational Academy of Sciences
NASANational Aeronautics and Space Administration
NBNota bene
NCCNetwork Control Center
NCPNorth Celestial Pole
NCSTNaval Center for Space Technology
NENoise Equivalent
NEDNASA/IPAC Extragalactic Database
NEFNuclear Enhancement Factor
NELGNarrow Emission Line Galaxy
NEPNorth Ecliptic Pole
NFSNetwork File System
NGCNew General Catalogue
NGPNorth Galactic Pole
NLRGNarrow Line Radio Galaxy
NLSy1Narrow Line Seyfert 1 Galaxy
NOANew Obligation Authority
NORADNorth American Air Defense Command
NPNarrative Procedures
NRNumerical Recipes
NRANASA Research Announcement
NRLNaval Research Laboratory
NRLNarrow Line Region
NSNeutron Star
NSENavier-Stokes Equation
NSF:National Science Foundation
NSSTCNational Space Science and Technology Center
NuSTARNuclear Spectroscopic Telescope Array
O-Ohio State University Radio Survey Catalog
OARINAF Osservatorio Astronomico di Roma
OCDOperational Concept Document
OEMOriginal Equipment Manufacturer
OGIPOffice of Guest Investigator Programs
OSOperating System
OSSNASA Office of Space Science
OSSEOriented Scintillation Spectrometer Experiment on CGRO
OSUThe Ohio State University
OVVOptically Violent Variable
P6/P7/P8Pass 6/7/8 version of the LAT Instrument Response Functions
PASPPublications of the Astronomical Society of the Pacific (scientific Journal)
PBPublication Board
PBHPrimordial Black Hole
PBHPrimordial Black Hole
PDB Project Database
PDEPartial Differential Equation
PDGParticle Data Group
PDMPProject Data Management Plan
PDRPreliminary Design Review
PDSPower Density Spectrum
PDTPacific Daylight Time
PDUPacket Data Unit
PDUPower Distribution Unit
PEPulsar Ephemerides
PEPulsar Ephemerides
PEGPassive Elliptical Galaxy
PGWPerugia Wavelet
PHAPulse Height Analyzer
PhDPhilosophiae Doctor (doctor of philosophy)
PIPrincipal Investigator
PICProton-Induced Cascade
PIMMSPortable, Interactive, Multi-Mission Simulator
PKSParkes Radio Catalog
PLAPianificazione del progetto
PMTPhoton Multiplier Tube
PNGPortable Graphic Network
POEPublic Outreach and Education
PPParent Population
PPPair Production
PRAPublic Relation Activity
PRJSchema del progetto
PRLPhysical Review Letters
PRRProgress Report
PSPoint Source
PSAPoint Source Analysis
PSDPower Spectral Density
PSFPoint Spread Function
PSNPiano Spaziale Nazionale
PSPCPosition Sensitive Proportional Counter
PSTPacific Standard Time
PTProduct Tree
PTUGPPulsar Timing Using Geocentered Photons
PVOPerformance, Verification, and Optimization
PWNPulsar Wind Nebula
QDEQuantum Detection Efficiency
QEDQuantum Electrodynamics
QGQuantum Gravity
QLAQuick Look Analysis
QPOQuasi-Periodic Oscillations
QSQuiet Sun
QSOQuasi Stellar Object
RARight Ascension
RARocking Angle
RAIDRedundant Array of Independent Disks
RBRelativistic Beaming
RBLRadio-selected BL Lac object
RDBMSRelational Data Base Management System
RdORichiesta d'Offerta
RDBRelational Database
RDBMSRelational Database Management System
RDQRun Data Quality
RHELRed Hat Enterprise Linux
RIDReprocessing Instrument Data
RLRadio Loud
RLFRadio Luminosity Function
RLQRadio-Loud Quasar
RMRelease Manager
RMResponse Matrix
RMFRedistribution Matrix File
RMSRoot Mean Square
ROIRegion Of Interest
RPMRed Hat Package Manager
RQRun Quality
RQRadio quiet
RQQRadio-Quiet Quasar
RSPRoutine Science Processing
RTRequest Tracker
RTRemote Terminal
RTSRelative Time Sequence
RTTReal Time Telemetry
RXROSAT X-ray Catalog
RXTERossi X-Ray Timing Explorer
SAASouth Atlantic Anomaly
SAGENAPScientific Assessment Group for Experiments in Non-Accelerator Physics (DOE and NSF)
SAItSocietà Astronomica Italiana
SAOSmithsonian Astrophysical Observatory
SASScience Analysis System
SASScience Analysis Software
SAS-2Small Astronomy Satellite 2
SAXBeppo-SAX, Satellite per Astronomia X
SBSpeakers Bureau
SBGStarburst Galaxy
SBGStarburst Galaxies
SCService Challenge
SciOpsScience Operations
SCIPPSanta Cruz Institute of Particle Physics at UCSC
SCLSLAC Central Linux
SConsSConscript open source software development platform
SCPSouth Celestial Pole
SDRSystem Design Review
SEDSpectral Energy Distribution
SEPSouth Ecliptic Pole
SFSolar Flare
SFStructure Function
SFOFSpace Flight Operations Facility
SGStarburst Galaxy
SGCScience Group Coordinator
SGPSouth Galactic Pole
SGRSoft Gamma-ray Repeater
SiSSiS Signal in Space
SISSSupporto Informatico Specialistico e Sistemistico
SLACStanford Linear Accelerator Center
SMBHSuper Massive Black Holes
SMCSmall Magellanic Cloud
SMESmall and Medium Enterprise
SNRSupernova Remnant
SOScience Operations
SODMScience Operation Data Monitor
SORSuccessive Overrelaxation
SQLStructured Query Language
SRSchwarzschild radius
SRSpecial Relativity
SRDScience Requirement Document
SRSSoftware Requirements Specification
SSASynchrotron Self-Absorption
SSACSenior Scientist Advisory Committee
SSCSynchrotron Self Compton
SSDSilicon Strip Detector
SSRQSteep Spectrum Ragio Quasar
SSUSonoma State University
STScience Tools software
STILStarlink Tables Infrastrucutre Library
STCScience Timeline Calendar
STScISpace-Telecope Science Institute
SUStanford University
SU-HEPLStanford University Hanson Experimental Physics
SUMSoftware User's Manual
SW, S/WSoftware
SWShock Waves
SWGScience Working Groups
SwiftSwift Gamma Ray Burst Explorer Mission
T&DFTrigger and Dataflow
TAIInternational Atomic Time
TBCTo Be Confirmed
TBDTo Be Determined
TBRTo Be Reviewed
TDTechnical Document
TDTempo Determinato
TDATime Domain Astronomy
TDMTridiagonal Matrix
TDRSS/ TDRSTracking and Data Relay Satellite System
TETest Engineer
TETransport Equation
TEMTower Electronics Module
TeVTera (10^12, trillion) electronvolts
TFTransfer Function
TGFTerrestrial Gamma-ray Flash
TKRLAT Tracker Subsystem
TMTechnical Meeting
TNTechnical Note
TNGTelescopio Nazionale Galileo
ToOTarget of Opportunity
ToTTime over Threshold
TPGTrigger Pattern Generator
TSTest Statistics
TSTime Series
TSTransient Survey
TSATimeseries Analysis
TSMTest Statistics Map
TSRTechnical and Science Report
TTGTelemetry Table GUI
UBVRIU,B,V,R,I photometric system
UCSCUniversity of California at Santa Cruz
UGSUser Ground Segment
ULIRGUltraluminous Infrared Galaxy
UPSUninterruptible Power Supply
UCSCUniversity of California at Santa Cruz
UTCUniversal Time Coordinated
UVOTUltraViolet and Optical Telescope (Swift instrument)
UWUniversity of Washington
VDDVersion Description Document
VERITASVery Energetic Radiation Imaging Telescope Array System
VHEVery High Energy
VIVariability Index
VLAVery Large Array
VLBAVery Long Baseline Array
VLBIVery Long Baseline Interferometry
VO, VOYVirtual Observatory
VOEVirtual Observatory Event
VPViewing Period
WAMWeb Application Manager
WAMWeekly Analysis Meeting
WBDWork Breakdown Description
WBSWork Breakdown Structure
WCSWorld Coordinate System
WDWhite Dwarf
WEBTWhole Earth Blazar Telescope
WGWorking Group
WIMPWeakly Interacting Massive Particle
WIRED World-Wide Web Interactive Remote Event Display (BaBar)
WMAPWilkinson Microwave Anisotropy Probe
WPWorking package (pacco di lavoro)
WRWolf-Rayet star
WSCWhite Sands Complex
WWWWorld Wide Web
XBLX-ray Selected BL Lac Object
XLFX-ray Luminosity Function
XMLeXtensible Markup Language
XMMXMM-Newton, X-ray Multi-Mirror Mission
XRBX-Ray Background
XRBX-ray Binary
XRTX-ray Telescope (Swift instrument)
XSPECX-ray spectral-fitting program
XTERossi X-ray Timing Explorer
zSymbol for redshift
ZAZenith Angle
ZPZero Point