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EXOHGLS - EXOSAT/CMA High Galactic Latitude Survey |
HEASARC Archive |
The sample of sources in this cataogue has been selected from the CMA database, which it has been generated using a standard processing on the LE data. The source detection algorithm used a sliding cell method. The size of the search cell is such as to maximize the sensitivity across the field of view. For more information about the LE processing see the documentation in the CMA database.
The images are in linearized detector coordinates and de-blurred (to account for fluctuations of the pointing position which were quite small). The lightcurves are background subtracted and a time resolution of 2^n seconds, where n was optimized such that the average number of counts per bin is 0.3.
* log in to the `legacy.gsfc.nasa.gov` anonymous ftp area * go to `caldb/data/exosat/cma/cpf` * copy the `.rmf` file for the filter instrument combination you need * start XSPEC, then:model wabs po (or whatever your model is) fakeit none 10000 (or whatever your exposure is) flux 0.1 2.5
The `fakeit` and `flux` commands will give the flux and count rate for the model you have specified.* 7 = 3000 (thin) lexanParameters
Name
The EXOHGLS catalog name of the EXOSAT target/field.Alt_Name
The name of the EXOSAT target/field. There are many serendipitous sources in the EXOSAT LE images, and in some cases the name given here will reflect the original target name and not the actual source name.ID_Number
Source order numberClass
Source Classification. Type 'class' at the browse prompt for more info. Source not identified as the class filed set to 'uniden'.RA
The RA is the Right Ascension of the detected source.Dec
The Dec is the Declination of the detected source.LII
The galactic longitude of the source.BII
The galactic latitude of the source.Al_Count_Rate
Counting rate from the Al/P filter, if available from an observation of the same source made within one day. `AL count rate error` gives the error on the Al/P counting rate.Al_Count_Rate_Error
Al-Par Count Rate ErrorBo_Count_Rate
Counting rate from the boron filter, if available (see the `AL count rate` description). `BO count rate error` gives the error on boron counting rate.Bo_Count_Rate_Error
Boron Count Rate ErrorX_Pixels
For imaging instruments, the X pixels coordinate of the source in the detector is given by the parameter `X pixels`. The X value ranges between -1024 and 1023.Y_Pixels
For imaging instruments, the Y pixels coordinate of the source in the detector is given by the parameter `Y pixels`. The Y value ranges between -1024 and 1023.File_Image
The file_image parameter contains the file name of the associated image.Lightcurve_Prefix
Rates buffer indentifier (first letter)Res_Of_Lc
Gives the time resolution of the associated data product lightcurve in seconds. The time resolution was 2^n seconds, where n was optimized such that the average number of counts per bin is 0.3.Time
The `time` of the observation refers to the start time. This is listed as yr.day, where yr is the last two digits of the year and day is the day of the year e.g., day 300 of 1984 is 84.300. All times are stored internally as a short history file key (SHF), which is the number of seconds before or after 1 January 1980 at 00:00 hrs UT. Times are accurate to the nearest second.IRAS_Flux_1
12-micron IRAS FluxProcessed_Date
MJD key for buffer creationInstrument
The instrument paramater records which of the two telescope+detector combination, LE1+CMA1 or LE2+CMA2, were used in the observation to detect the source. The values are L1, for the combination LE1+CMA1, and L2, for the combination LE2+CMA2.Diamond_Filter
Some observation were carried out with an OBC program that sets a 'diamond' filter. This filter electronically screened out the outer part of the field of view. The resulting image, which is shaped as a diamond, covers only a fraction of the 2 X 2 deg. If the diamond filter wa s in used than the DIAMOND_FILTER paramater is set to 1 otherwise its value is 0.ROSAT_ID
ROSAT Id (spare)Filter
The filter numbers are
* 6 = al/p
* 8 = boron
* 2 = PPL
* 3 = 4000 (thick) lexan
Offset_Detection_Angle
Distance from xpix=15, ypix=15Observed_Variance_Ta1
Observed Variance in TA1Expected_Variance_Ta1
expected variance in TA1Exposure_Time
The `exposure` is the total on-source observation time in seconds. This includes all dead time effects, interruptions in coverage, etc.Old_Deadtime
Dead Time CorrectionSequence_Number
Sequence NumberMe_Count_Rate
Counting rate from the ME detector during this observation (warning: this may not cover exactly the same time interval), it also covers the central field of view and so will include all sources seen by the LE. `ME count rate error` gives the error on the count rate.Me_Count_Rate_Error
ME Count Rate ErrorIRAS_Flux_2
25-micron IRAS FluxIRAS_Flux_3
60-micron IRAS FluxDetection_Significance
The probability of the detection being due to random chance. Note, this is not scaled for the independent number of search attempts in an image.Tape_No
Archival Tape Number Where Files Are StoredPI_Code
Principal Investigator CodeProposal_Type
Proposal Type (HLX)Qflag_Me
ME Quality FlagFile_Bglcurve
File name of the associated background lightcurve. One background lightcurve is associated to each image.Redshift
Redshift or HD Number of CounterpartOld_Nh_21cm
NH (10**19 cm-2) in the GalaxyNH_21cm
21 cm NH thru the galaxy H cm**-2 from Starke et al.Me_3_To_6_Count_Rate
ME Count Rate in 3-6 keV BandMe_3_To_6_Count_Rate_Err
ME Count Rate Error in 3-6 keV BandMe_1_To_3_Count_Rate
ME Count Rate in 1-3 keV BandMe_1_To_3_Count_Rate_Err
ME Count Rate Error in 1-3 keV BandError_Radius
The 90-percent confidence uncertainty in arc seconds for the source position.Ipc_Count_Rate
IPC Count RateIpc_Count_Rate_Error
IPC Count Rate ErrorVmag
Visual MagnitudeRadio_5ghz_Flux
Radio Flux (mJy) at 5 GHzDeadtime_Correction
detector deadtime correction factorRadio_Flag
Flag for Radio EmissionSerendipity_Flag
Flag for Serendipitous SourcesBackground_Per_Sqpix
Background Level (cts/s/sq.pixel)Count_Rate
The `count rate` and `count rate error` are the average counting rate (counts per sec) over the observation and its associated one sigma uncertainty.Count_Rate_Error
Error on Count RateObserved_Variance_Ta2
Observed Variance in TA2Expected_Variance_Ta2
expected variance in TA2IRAS_Flux_4
100-micron IRAS FluxLast_Update
Date of Last Record UpdateBV_Color
B-V ColorQflag_Le
Quality flag for the LE. This is a number between 1 and 5, where 5 is excellent, and 1 means there may be a serious problem with the entry. A value of 3 means that the entry should be checked. For example, all boron filter entries have a qflag of 3, to warn of the problem with the psf for soft sources observed with this filter.UB_Color
U-B colorFile_Lcurve
File name of the source lightcurve.Quality_Check
Visual Quality of DetectionPoint_Source_Flag
Point Source FlagContact Person
Questions regarding the EXOHGLS database table can be addressed to the HEASARC User Hotline.
Page Author: Browse Software Development Team
Last Modified: Monday, 08-Nov-2004 11:24:45 EST