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EUVEMASTER - EUVE Archive and Observation Log

HEASARC
Archive

Overview

This catalog of the EUVE Science Archive has been constructed based on information provided by personnel of the Center for Extreme-Ultraviolet Astrophysics (CEA), and is made available in the current EUVEMASTER database table. Most of the information in the catalog is also in the headers of the FITS files. The HEASARC now has nearly all of the 1378 pointed EUVE Deep Survey/Spectrometer (DS/S) datasets that were processed by CEA until its closing in March 2001. There are a small number of observations that were made in the year 2000 for which the HEASARC does not currently have the corresponding datasets. Notice that this catalog does not contain entries corresponding to EUVE observations in scan mode or where the files received by the HEASARC were not of the normal image or events type.

Provenance

This is the 7th (and possibly final) version of the EUVEMASTER database, last updated in June 2001. This catalog has been constructed based on information provided by staff members of the Center for Extreme-Ultraviolet Astrophysics (CEA) in Berkeley, CA, whose help is gratefully acknowledged.

Data Products

The primary data products for the EUVE Master Catalog are two Science Archive FITS files, one being an event file and the other an image file, for each entry (which corresponds to a unique EUVE observation). There are two types of higher-level secondary data products that are also available: the first type is a link to the preview webpage at STScI that contains an automatically generated plot of the total EUVE spectrum for the observation, as well as other information such as literature references that have made use of this particular dataset; the second type are available for objects that were included in "The EUVE Stellar Spectral Atlas" of Craig, N., Abbott, M., Finley, D., Jessop, H., Howell, S.B., Mathioudakis, M., Sommers, J., Vallerga, J.V., and Malina, R.F. which was published in 1997 in ApJS, vol. 113, pp. 131 et seq. These products comprise FITS and PostScript versions of the spectra of 95 bright stellar sources observed by EUVE. The HEASARC has attached the spectral atlas data products for a given source to every individual observation of that source, i.e., we have not attempted to distinguish which observation or observations of a multiply observed source were used to construct the stellar atlas spectra.

Known Problems and Anomalies

There are 13 Science Archive FITS data sets for observations made in the year 2000 that are currently missing from the HEASARC's EUVE Data Archive. There is also one observation for which the image FITS file is missing. The HEASARC has been unsuccessful so far in retrieving copies of these missing files from the original PIs. If anyone has copies of these data files, please contact the HEASARC Help Desk. The following observations are missing their respective Science Archive FITS data sets:
 Name                   Observed Date        Archive File
 -----------------+-----------------------+--------------------------------
 EUVE J0932 26.9     2000-03-14 03:02:57     euve_j0932_26_9__0003140302N
 EUVE J0932 26.9     2000-03-18 17:11:17     euve_j0932_26_9__0003181711N
 Virgo Positive      2000-04-05 00:02:08     virgo_positive__0004050002N
 Virgo Positive      2000-04-08 18:06:51     virgo_positive__0004081806N
 Virgo Positive      2000-04-13 23:20:00     virgo_positive__0004132320N
 Virgo Positive      2000-04-19 15:27:49     virgo_positive__0004191527N
 Virgo Negative      2000-04-19 23:17:06     virgo_negative__0004192317N
 ACO 2149            2000-06-26 08:48:59     aco_2149__0006260848N
 EUVE J0006 29.0     2000-06-26 22:44:00     euve_j0006_29_0__0006262244N
 EUVE J0006 29.0     2000-07-04 10:05:57     euve_j0006_29_0__0007041005N
 EUVE J0006 29.0     2000-07-08 03:46:56     euve_j0006_29_0__0007080346N
 AR Lac              2000-09-04 05:18:59     ar_lac__0009040518N
 AR Lac              2000-09-08 10:44:42     ar_lac__0009081044N
 EUVE J0613-23.9     2000-11-06 03:49:27     euve_j0613-23_9__0011060349N (missing image file only)
In addition to the above missing (or partially missing) data sets, there are also two Science Archive FITS data sets for what appears to be the same observation: EUVE J0356-366 and 2EUVE J0356-36.6. Current speculation is that the pointing position may have been updated and the data was reprocessed at some point.

Parameters

Name
The target name; this is the official name under which the target was processed for the EUVE Archive. It is not necessarily the name under which the target was originally proposed or observed. A single name has been consistently used thoughout the archive for targets which were observed more than once. In some cases, the target name listed in the file itself is an alternate name for the object.

RA
The right ascension in the default equinox. Data originated in J2000 coordinates, notice and is processed using standard algorithms if another equinox is selected. The original J2000 coordinates were used as the coordinates of the source when CEA processed the data. However, these are not necessarily the same as the coordinates that were used to point the spacecraft during the actual observation. They are typically either taken from Simbad (with proper motions applied) or were supplied by the Guest Observer. CEA used the same coordinates throughout the EUVE archive for multiple observations of the same source, except in certain special cases.

Dec
The declination in the default equinox. Data originated in J2000 coordinates, notice and is processed using standard algorithms if another equinox is selected. The original J2000 coordinates were used as the coordinates of the source when CEA processed the data. However, these are not necessarily the same as the coordinates that were used to point the spacecraft during the actual observation. They are typically either taken from Simbad (with proper motions applied) or were supplied by the Guest Observer. CEA used the same coordinates throughout the EUVE archive for multiple observations of the same source, except in certain special cases.

LII
The Galactic longitude of the object.

BII
The Galactic latitude of the object.

Observed_Date
This is the GMT (UT) time, to the nearest second, of the start of the observation. The target name and observation date together serve to uniquely identify each EUVE observation.

Day_Night_Flag
This is either the word "night" or "day" indicating which part of the observation is being cataloged. Some observations will have both parts, others will only have a night part. In general, only 'night' data have been archived for most sources.

Exposure
This is the median exposure for this observation, in seconds. There are four EUVE detectors which normally collect data simultaneously during an observation. Each detector will have a different exposure time. In this field the median of the exposures of the individual detectors is listed, in units of kiloseconds, and rounded off to the nearest kilosecond. Note that sometimes one detector can be way off from the others and skew this number, or an observation can be very short producing an exposure time of zero. For the true exposure times, the user would need to obtain the actual data files for an observation, and look in the headers of the images.fit extensions. This parameter was given with a precision of kiloseconds in the original, as-published table.

PI_Name
The name of the Principal Investigator (PI) of the proposal which was associated with this observation in the CEA database. This is not always a very meaningful field, because many times multiple proposals (and PIs) were given simultaneous data rights the to the target in the same observing cycle. In that case, only one of the PIs is listed here. The observer is listed as "EUVE" for targets which were scheduled as calibration targets. However, for most calibration targets, there was also a PI to whom the data was for an interval of time proprietary; unfortunately, this database does not contain the PI names for such calibration targets.

Total_File_Size
The sum of the sizes of the events and image FITS files for the particular observation, in their original formats, in kilobytes. The events files normally consume a lot more space than the image files. Also notice that, since the HEASARC stores these files in gzipped format, this parameter overestimates by a factor of 1.5-2 their actual sizes in the HEASARC data archive.

Object_Type
A broad category for the target; values include:

        wd  white dwarf
      late  late-type star
     early  early-type star
        cv  cataclysmic variable
        ex  extragalactic
        ss  solar system
    pulsar  pulsar
        pn  planetary nebula
      noid  unidentified
      lmxb  low-mass X-ray binary
       snr  supernova remnant
       grb  gamma-ray burster
     other  none of the above
  

Spect_Type
This is the spectral type, for stars and white dwarfs, or a sub-classification for some other categories. It is left blank where not applicable or known.

GO_Number
The old ID number that the target was assigned in the now obsolete EUVE spectral browser and archive. Notice that there is not a one-to-one correspondence between the old archive and the current one, so that some targets have more than one ID number associated with them, and other IDs are used by multiple targets. The old ID might be of use for historical purposes or for users who know the old ID of a target that they want. EUVE stopped assigning ID numbers to publically released targets as of the Feb. 1, 1998 release.

Public_Date
The date on which this observation will become public. If this field is blank, the target is already public. If there is a date present, this target is still proprietary to its Guest Observer and should not be made public until the indicated date or thereabouts. Targets observed in Cycles 1-4 of the EUVE Guest Observer program have one year proprietary periods. In Cycle 5 (which began in 1997) and later cycles the period is six months. The period begins when CEA delivers the data, not when it was observed, and exceptions are sometimes made if there was a problem with the data delivery, etc., so the public dates cannot be inferred from the data files themselves. Also, some EUVE observations are done in parts over an extended period of time; in such cases, the proprietary period is determined from the delivery date of the last part to the PI.

Archive_File
Root of the file name under which the data can be retrieved from the archive system. This information is derived from the target name and observation date and time. Interested users might note the Archive_File values for the observations in which they are interested, and then download the data sets using anonymous FTP to ftp://legacy.gsfc.nasa.gov/euve/data/fits/.

Class
Browse classification, derived from the spect_type parameter in conjunction with the object_type parameter.


Contact Person

Questions regarding the EUVEMASTER database table can be addressed to the HEASARC User Hotline.

Page Author: Browse Software Development Team
Last Modified: 10-Jul-2008