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EUVECAT1: Help

The First EUVE Source Catalog

Overview

The EUVECAT1 database contains a detailed list of verified bright sources detected during the survey phase of the Extreme Ultraviolet Explorer (EUVE) mission (calibration targets are also included).

Additionally, this database includes the sources derived from the First EUVE Source Catalog Supplementary list, which were a part of the Bright Source List (BSL) but not formally included in the First EUVE Source Catalog (FESC) because they did not meet the criteria for inclusion.


History

Both the BSL and the FESC used exactly the same raw data, however newer and more stringent detection and processing algorithms were used to compile the FESC. As a result, the new list of sources did not exactly match the BSL. The majority of entries in this list were reprocessed using the newer FESC algorithms, however some entries have been copied directly from the BSL. If a source in this database is accompanied by at least one countrate uncertainty, the source information (including position, countrates and possible identification) was recalculated during the building of the FESC. If no countrate uncertainties are present, the source information was copied directly from the BSL.

Two distinct surveys, the All-Sky and Deep Surveys, were conducted by the four EUVE telescopes during the first six months of the mission, as well as during short periods of "gap filling" during the first six months of the Guest Observer (GO) program.

The All-Sky Survey was conducted by three scanning telescopes ("scanners") with four distinct filters (Lex/B, Al/C, Ti/Sb/Al or "Dagwood", and Sn/SiO) covering the wavelength region 58-740 . During the All-Sky Survey phase, the scanning telescopes mapped approximately 97% of the entire sky with exposure times of greater than 20 seconds along the ecliptic and much higher at the poles. Concurrently, the Deep Survey (DS) telescope conducted a much more sensitive survey of a 2 Degrees x 180 Degrees band along the ecliptic in two filters (Lex/B and Al/C) covering the wavelength region 67-364.


Parameters

Name
Name of the EUVE source. The adopted format is EUVE_Jhhmm[+-]dd.d.  Note that
the format used in this database is slightly different from that used in the
published version of the catalog, where the declination in the EUVE name is
multiplied by ten. 

VMAG
Photographic magnitude.

RA
The right ascension of the object.

Dec
The declination of the object.

LII
The galactic latitude of the object.

BII
The galactic longitude of the object.

LEX
Countrates of the EUV source in Lexan/B filters. The units are in counts per
second. The NULL value means the source countrate was less than three times the
measurement uncertainty. 

LEX_Err
Statistical uncertainty of the EUVE sources in Lexan/B filters. The units are
in counts per second. A NULL value appears when no countrate is given for that
filter. 

ALC
Countrates of the EUV source in Al/Ti/C filters. The units are in counts per
second. The NULL value means the source countrate was less than three times the
measurement uncertainty. 

ALC_Err
Statistical uncertainty of the EUVE sources in Al/Ti/C filters. The units are
in counts per second. A NULL value appears when no countrate is given for that
filter. 

DAG
Countrates of the EUV source in Ti/Sb/Al filters. The units are in counts per
second. The NULL value means the source countrate was less than three times the
measurement uncertainty. 

DAG_Err
Statistical uncertainty of the EUVE sources in Ti/Sb/Al filters. The units are
in counts per second. A NULL value appears when no countrate is given for that
filter. 

TIN
Countrates of the EUV source in Sn/SiO filters. The units are in counts per
second. The NULL value means the source countrate was less than three times the
measurement uncertainty. 

TIN_Err
Statistical uncertainty of the EUVE sources in Sn/SiO filters. The units are in
counts per second. A NULL value appears when no countrate is given for that
filter. 

DSL
Countrates of the EUV source in Deep Survey Lexan/B filters. The units are in
counts per second. The NULL value means the source countrate was less than
three times the measurement uncertainty. 

DSL_Err
Statistical uncertainty of the EUVE sources in Deep Survey Lexan/B filters.
The units are in counts per second. A NULL value appears when no countrate is
given for that filter. 

DSA
Countrates of the EUV source in Deep Survey Al/C filters. The units are in
counts per second. The NULL value means the source countrate was less than
three times the measurement uncertainty. 

DSA_Err
Statistical uncertainty of the EUVE sources in Deep Survey Al/C  filters. The
units are in counts per second. A NULL value appears when no countrate is given
for that filter. 

Qual
A qualitative measure of the quality of the match between the EUVE source and
the possible optical counterpart. 1 means a probable match, 2 means a possible
match. A quality of NULL means that either there is no known optical
counterpart, or that the EUVE source is identified as a possible UV leak. 

ID_1
Possible optical counterpart identification of the EUV source as taken from
internal catalogs, SIMBAD database search and/or communication with the EUVE
Optical Identification group. Possible counterparts all lie within two
arcminutes of the calculated source position. The notation "NO ID" was used for
unidentified sources. 

ID_2
Another possible optical counterpart identification of the EUV source as taken
from internal catalogs, The notation "NO ID" was used for unidentified sources. 
Not available from the Supplementary list.

SPECT_TYPE
The spectral type (if known) of the possible optical counterpart for the EUVE
source. Most of the notations are standard usage except "CSPN" refers to the
central star of a planetary nebula and "Puls" is a pulsar. An empty field
indicates no known spectral type. 

SEP
The separation between EUVE source and its optical counterpart, measured in
arcseconds. A value of NULL indicates there was no optical counterpart found,
and hence no separation could be computed. 

Comments
Miscellaneous comments. The key is: 
-------------------------------------------------------------------------------
   RE: source is also in the ROSAT WFC catalog 
   4U: source is in the 4th Uhuru catalog 
   TD1: source seen in the TD1 survey 
   1E: source seen in the 1st Einstein survey 
   LTT: Luyten 1957, Luyten 1961 
-------------------------------------------------------------------------------
In three cases, sources seen in the All-Sky Survey were also seen in the Deep
Survey. For these sources, the separation given in the sep field refers only to
the All-Sky separation. Each of these three sources have been assigned a unique
comment, which gives the separation as measured through the Deep Survey
telescope: 

-------------------------------------------------------------------------------
   SEP1: sep=71 arcseconds 
   SEP2: sep=137 arcseconds 
   SEP3: sep=108 arcseconds 
-------------------------------------------------------------------------------

Supplements
A Flag determining the difference between sources culled from the First EUVE
Source Catalog (N), and those derived from the First EUVE Source Catalog
Supplementary List (Y).

Class
BROWSE classification type.  The classification is based on the `Type`
parameter, if one is available.

References

EUV All Sky Survey and Deep Survey confirmed data.

Contact Person

Questions regarding the EUVECAT1 database table can be addressed to the HEASARC User Hotline.
If you have any problems, please consult the help page or mail ledas-help@star.le.ac.uk
 
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