ME ivo://nasa.heasarc/me NASA/GSFC HEASARC HEASARC 2026-10-09 NASA/GSFC HEASARC help desk heasarc-vo at athena.gsfc.nasa.gov Observation The EXOSAT Medium Energy experiment (ME) was an array of eight proportional counters with a total geometric area of 1600 cm<sup>2</sup>. The field of view was square and 0.75 degrees x 0.75 degrees FWHM on each side. Each proportional counter consisted of an argon chamber on top of a xenon chamber separated by a 1.5 mm beryllium window. The fractional energy resolution, dE/E, was 21(E/6 keV)<sup>-0.5</sup> percent FWHM for the argon chambers. The output from each chamber was pulse height analyzed into 128 channels with the argon chambers sensitive from 1-20 keV and the xenon from 5-50 keV. To optimize the background subtraction, each half of the detector array was alternately offset to a source-free region of sky to monitor the particle background. Only results from the argon detectors are included in the EXOSAT ME database. The high count rates given by the ME required OBC (on board computer) programs to compress the data prior to their being telemetered. Depending on the objective of the observation the OBC programs traded time resolution against spectral information. Depending on the telemetry load, and the OBC programs running for the other two experiments, two or three ME programs could be run simultaneously. The spectral orientated programs gave spectra plus intensity profiles. The timing programs gave purely intensity profile data with in some cases selectable channels. The highest time resolution possible for a single selectable energy band was 0.2 ms. The products available within this database has been created using the data sampled by the spectral orientated OBC programs. This is a service provided by NASA HEASARC . https://heasarc.gsfc.nasa.gov/W3Browse/all/me.html Archive Research served-by HEASARC TAP https://heasarc.gsfc.nasa.gov/xamin/vo/cone?showoffsets&table=me& GET text/xml 180 99999 true 10.1991097315737 -79.2409263973148 0.75 https://heasarc.gsfc.nasa.gov/xamin/vo/tap https://heasarc.gsfc.nasa.gov/cgi-bin/W3Browse/getvotable.pl?name=me GET text/xml https://heasarc.gsfc.nasa.gov/cgi-bin/W3Browse/w3query.pl?tablehead=name=heasarc_me&Action=More+Options&Action=Parameter+Search&ConeAdd=1 EXOSAT 0.75 X-ray public me EXOSAT ME Spectra and Lightcurves name Object Designation meta.id;meta.main char nullable "time" MJD of Start mjd time.start;obs double nullable sequence_number Sequence Number meta.id short nullable qflag_me Spectrum Quality Control Flag meta.code.qual short nullable exposure Duration (seconds) s time.duration;obs.exposure float nullable count_rate Cts/sec/4D (CH:6:34) ct/s/4D phot.count;em.X-ray float nullable count_rate_error Err/sec/4D ct/s/4D stat.error;phot.count;em.X-ray float nullable ra Source Right Ascension degree pos.eq.ra;meta.main double nullable dec Source Declination degree pos.eq.dec;meta.main double nullable "__x_ra_dec" System unit vector column double nullable "__y_ra_dec" System unit vector column double nullable "__z_ra_dec" System unit vector column double nullable "__row" System index column char nullable pi_code PI Code meta.id.PI short nullable obs_var_1_8 Observed Variance 1-8 keV stat.variance;phot.count;em.X-ray.medium float nullable rate_4 Cts/s/4dets band 4, 10-15 keV ct/s/4D phot.count;em.X-ray.hard float nullable sr_error Error in Softness ratio stat.error;phot.flux;arith.ratio float nullable lightcurves_num # of 400pt Rates Files Created meta.number;meta.file;phot short nullable roll_angle Roll Angle (deg*10) 10^-1_degree instr.param;pos.posAng short nullable p4 Best fit model parameter 4 stat.param;meta.modelled float nullable file_agif A Detector Lightcurve GIF meta.dataset;meta.file;phot char nullable rms_var_1_8 RMS Variability 1-8 keV src.var;em.X-ray.medium float nullable pl_chisqr Chisq for PL stat.fit.chi2 float nullable rms_var_bg_error RMS Variability BG error stat.error;src.var;em.X-ray;instr.background float nullable bb_kt Temp for BB keV phys.temperature;stat.fit float nullable p5 Best fit model parameter 5 stat.param;meta.modelled float nullable exp_var_3_8 Expected Variance 3-8 keV stat.variance;phot.count;em.X-ray.medium float nullable obs_var_3_8 Observed Variance 3-8 keV stat.variance;phot.count;em.X-ray.medium float nullable p6 Best fit model parameter 6 stat.param;meta.modelled float nullable obs_var_int10 Observed Variance int*10 stat.variance float nullable tres Integration time of spectrum s time.epoch;time.resolution float nullable exp_var_10s Expected Variance 10s stat.variance;phot.count float nullable lii Galactic Longitude degree pos.galactic.lon double nullable co_kt Temp for Co keV phys.temperature;stat.fit float nullable file_spectrum Spectrum Filename meta.dataset;meta.file;spect char nullable rms_var_10s_error RMS Variability 10s error stat.error;src.var;em.X-ray float nullable rms_var_int10_error RMS Variability int*10 error float nullable totnlcurve Total # of roots w/same seq # short nullable exp_var_int10 Expected Variance int*10 stat.variance float nullable th_nh Nh for TH 10^22_atoms/cm^2 phys.columnDensity float nullable exp_var_1_8 Expected Variance 1-8 keV stat.variance;phot.count;em.X-ray.medium float nullable root_2 Root 2 name char nullable p2 Best fit model parameter 2 stat.param;meta.modelled float nullable rate_total_error Error/s/4dets in total band ct/s/4D stat.error;phot.count;em.X-ray float nullable llcurve Char length of lightcurve name short nullable class Classification flag src.class short nullable file_dgif D Detector Lightcurve GIF meta.dataset;meta.file;phot char nullable rate_4_error Error/s/4dets band 4 10-15 keV ct/s/4D stat.error;phot.count;em.X-ray.hard float nullable rms_var_bg RMS Variability BG src.var;em.X-ray;instr.background float nullable rms_var_3_8 RMS Variability 3-8 keV src.var;em.X-ray.medium float nullable root_1 Root 1 name char nullable pl_alpha Alpha for PL pos.eq.ra;stat.fit float nullable point_ra Pointing Right Ascension degree pos.eq.ra double nullable tape_no File Number meta.id short nullable co_norm Norm for Co float nullable rms_var_3_8_error RMS Variability 3-8 keV error stat.error;src.var;em.X-ray.medium float nullable proposal_type Observation Type char nullable obs_var_1_3 Observed Variance 1-3 keV stat.variance;phot.count;em.X-ray.soft float nullable exp_var_bg Expected Variance BG stat.variance;phot.count;instr.background float nullable sr Softness ratio (1/2) phot.flux;arith.ratio float nullable chained Chained? *=start, L=continuation meta.code;obs char nullable point_dec Pointing Declination degree pos.eq.dec double nullable rate_1 Counts/s/4dets band 1, 1-3 keV ct/s/4D phot.count;em.X-ray.soft float nullable hr_error Error in Hardness ratio stat.error;phot.count;arith.ratio;em.X-ray.medium float nullable th_chisqr Chisq for TH stat.fit.chi2 float nullable aspec_done ASPEC Summary File exists? meta.code short nullable nlcurve Number of on-source lightcurves meta.number;phot short nullable nh_21cm Galactic NH atoms/cm^2 phys.columnDensity float nullable line_present 1=line, 0=no line in fit meta.code;spect.line short nullable rms_var_int RMS Variability int float nullable bb_norm Norm for BB float nullable last_update MJD of creation time mjd time.creation double nullable macro_name Macro Name char nullable rms_var_1_3_error RMS Variability 1-3 keV error stat.error;src.var;em.X-ray.soft float nullable file_lcurve Total root names 1 meta.dataset;meta.file;phot char nullable rms_var_1_3 RMS Variability 1-3 keV src.var;em.X-ray.soft float nullable th_norm Norm for TH float nullable tftsa_done TFTSA Summary File exists? meta.code;meta.file short nullable exp_var_1_3 Expected Variance 1-3 keV stat.variance;phot.count;em.X-ray.soft float nullable root_3 Root 3 name char nullable bii Galactic Latitude degree pos.galactic.lat double nullable hr Hardness ratio (4/3) phot.count;arith.ratio;em.X-ray.medium float nullable p9 Best fit model parameter 9 stat.param;meta.modelled float nullable macro_completed Macro completed OK ? short nullable process_date MJD of macro run mjd time.processing double nullable roots_num Total No. of root names short nullable co_alpha Alpha for Co float nullable rms_var_int_error RMS Variability int error float nullable packet_id Packet ID of Spectrum char nullable lspectra Char. length of spectrum name short nullable obs_var_int Observed Variance int stat.variance float nullable p7 Best fit model parameter 7 stat.param;meta.modelled float nullable rate_total Counts/s/4dets in total band ct/s/4D phot.count;em.X-ray float nullable num_spec Number of parameters meta.number;stat.fit short nullable rms_var_int10 RMS Variability int*10 float nullable obs_var_10s Observed Variance 10s stat.variance;phot.count float nullable nspectra # of spectra associated. w/entry meta.number;spect short nullable id_number Source order no. meta.id short nullable p8 Best fit model parameter 8 stat.param;meta.modelled float nullable obs_var_bg Observed Variance BG stat.variance;phot.count;instr.background float nullable rate_1_error Error/s/4dets band 1, 1-3 keV ct/s/4D stat.error;phot.count;em.X-ray.soft float nullable bg_files_num # of 400pt bckgd Rates Files meta.number;meta.file;instr.background short nullable p1 Best fit model parameter 1 stat.param;meta.modelled float nullable energy_line Line Energy keV float nullable chisqr Reduced Chisq stat.fit.chi2 float nullable p3 Best fit model parameter 3 stat.param;meta.modelled float nullable obs_var_exp Expected Variance int stat.variance;phot.count;em.X-ray float nullable pl_nh Nh for PL 10^22_atoms/cm^2 phys.columnDensity;stat.fit float nullable bb_nh Nh for BB 10^22_atoms/cm^2 phys.columnDensity;stat.fit float nullable pname name to be printed inc. blanks meta.id char nullable ew_line EW of line keV spect.line.eqWidth float nullable co_nh Nh for Co 10^22_atoms/cm^2 phys.columnDensity;stat.fit float nullable rms_var_10s RMS Variability 10s src.var;em.X-ray float nullable th_kt Temp for TH keV phys.temperature;stat.fit float nullable beta_angle Beta Angle (degrees) degree short nullable root_4 Root 4 name char nullable rate_2 Counts/s/4dets band 2, 3-6 keV ct/s/4D phot.count;em.X-ray.medium float nullable p10 Best fit model parameter 10 stat.param;meta.modelled float nullable spectral_model Best Fit model code meta.code;stat.param;meta.modelled short nullable end_time MJD of End mjd time.end;obs double nullable root_6 Root 6 name char nullable rate_3 Cts/s/4dets band 3, 6-10 keV ct/s/4D phot.count;em.X-ray.medium float nullable pl_norm Norm for PL float nullable co_chisqr Chisq for Co stat.fit.chi2;stat.fit float nullable rate_2_error Error/s/4dets band 2, 3-6 keV ct/s/4D stat.error;phot.count;em.X-ray.medium float nullable rms_var_1_8_error RMS Variability 1-8 keV error stat.error;src.var;em.X-ray.medium float nullable rate_3_error Error/s/4dets band 3, 6-10 keV ct/s/4D stat.error;phot.count;em.X-ray.medium float nullable proposal_code Proposal Code char nullable bb_chisqr Chisq for BB stat.fit.chi2;stat.fit float nullable root_5 Root 5 name char nullable tint Integr. time of intens. data s time.epoch;time.resolution float nullable