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EUVERAP2 - EUVE Right Angle Program, 2nd Catalog

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Overview

The Second Extreme Ultraviolet Explorer (EUVE) Right Angle Program (RAP) Catalog contains information on the detection of 235 extreme ultraviolet (EUV) sources, of which 169 are new detections, using the EUVE's RAP data. This catalog included observations made since the first EUVE RAP catalog (1994 January) and covered 17% of the sky. The EUVE RAP used the all-sky survey telescopes (also known as "scanners"), which were mounted at right angles to the Deep Survey and Spectrometer instruments, to obtain photometric data in four wavelength bands centered at 100 Angstroms (Lexan/B), 200 A (Al/Ti/C), 400 A (Ti/Sb/Al or Dagwood), and 550 A (Sn/SiO). The EUVE RAP2 Catalog contains source count rates and probable source identifications from the available catalogs and literature. The source distribution is similar to previous EUV catalogs with 2% early-type stars, 45% late-type stars, 8% white dwarfs, 6% extragalactic objects, 24% with no firm classification, and 15% with no optical identification.

Catalog Bibcode

1999AJ....117.2466C

References

The Second Extreme Ultraviolet Explorer Right Angle Program Catalog.
    Christian D.J., Craig N., Cahill W., Roberts B., Malina R.F.
   <Astron. J., 117, 2466 (1999)>
   =1999AJ....117.2466C

Provenance

This database was created at the HEASARC in May 2002 based on the ADC/CDS Catalog J/AJ/117/2466 and is derived from Tables 2, 3, and 4 the published paper.

Description

The Guest Observer (GO) phase of the EUVE mission accumulated pointed observations of over 400 unique sources in the period after the initial phase of the all-sky survey was completed (1993 January) to November 1998. The GO pointed observations primarily used the EUV Deep Survey and Spectrometer (DS/S) telescope. However, pseudoserendipitous observations continued through this phase by using the survey telescopes, which were mounted perpendicular to the DS/S in what became known as the Right Angle Program (RAP). The source detections from the first year of this program were presented in a paper by McDonald et al. (1994, AJ, 108, 1843), the First EUVE RAP Catalog, which covered observations through 1994 January. Table 3 of the Second EUVE All-Sky Catalog (Bowyer et al. 1996, ApJS, 102, 129, available in the HEASARC Browse system as the EUVECAT2 database table) includes miscellaneous EUVE detections and the EUVE RAP results though 1994 December; the selection criteria in Table 3 varied, and for this reason the authors of the Second EUVE RAP Catalog included RAP results since 1994 January.

One of the key advantages of RAP observations over the all-sky survey was that the exposure times for each field observed on the sky were generally much longer because they were dictated by the DS/S pointings. The catalog authors analyzed RAP pointings with a minimum exposure time of 10 ks so as to generally have significantly more exposure than the all-sky survey, which had only a few hundred seconds per exposure at intermediate ecliptic latitudes. Over 600 individual RAP pointings from 1994 January to 1998 November were identified. The almost 4 years of RAP Deep Survey and scanner pointings included in this catalog cover 17% of the sky with exposure times of at least 10 ks. The average exposure time is 55 ks with the 700 ks DS/S observation of 1H 0419-577 being the longest.


HEASARC Implementation

The HEASARC has combined data that were originally in 3 separate tables (Tables 2 - 4 in the published) Catalog to make this database table. These tables contain EUV count rates derived from 2 bandpasses of 3 separate instruments, namely the A and B Scanners (Table 2), the Long-Wavelength C Scanner (Table 3), and the Deep Survey (DS) telescope (Table 4). To differentiate entries from these 3 tables in the HEASARC database table, we have created a new parameter rap_sample that is set to 'scanner' for entries from Table 2, 'lw_scanner' for entries from Table 3, and 'deep_survey' for entries from Table 4. Three entries in Table 2 have EUVE source names that are identical with three entries in Table 3, although two of the three pairs have different positions quoted in the two tables. The HEASARC has thus left these three pairs as six separate entries, and did not attempt the merge them.

The pairs of bandpasses used for the EUVE A and B scanners and for the EUVE DS are similar, although not identical, and the HEASARC has used the same parameters, called le_count_rate and al_count rate, for their count rates. Notice that the le_count_rate for Table 2 entries (rap_sample = 'scanner') is the count rate in the Scanners A and B Lexan/B band from 58 - 174 A, or 0.071 - 0.21 keV, while the le_count_rate for Table 4 entries (rap_sample = 'deep_survey') is the count rate in the DS Lexan/B band from 67 - 178 A, or 0.07 - 1.18 keV'; also the al_count_rate for Table 2 entries (rap_sample = 'scanner') is the count rate in the Scanners A and B Al/Ti/C band from 156 - 234 A, or 0.053 - 0.079 keV, while the al_count_rate for Table 4 entries (rap_sample = 'deep_survey') is the count rate in the DS Al/C band from 157 - 364 A, or 0.034 - 0.079 keV.

Some of the EUV sources have two alternative source identifications (often, but not always, at other wavelengths) suggested for them in this catalog. Notice that, in such cases, the HEASARC has followed the structure of the original catalog and the CDS tables derived from it, and lists separate entries for the alternative identifications. For example, the EUV source EUVE J0241-006 is listed twice, once with the suggested ID of NGC 1068, and a second time with the suggested ID of 84 Cet. Thus, there are 257 entries in this database corresponding to 236 listed EUV sources.

Notice that this HEASARC table does NOT include the 36 entries in Table A1 of the published paper, since these are not detections of EUV emission, but are rather out-of-bandpass detections of B stars having strong UV and FUV emission.


Parameters

Name
The name of the EUVE source based on its position in J2000.0 equatorial coordinates.

RA
The Right Ascension of the EUVE source in the selected equinox. This was given in J2000.0 equatorial coordinates with a precision of 0.1 seconds of time in the original table.

Dec
The Declination of the EUVE source in the selected equinox. This was given in J2000.0 equatorial coordinates with a precision of 0.1 arcseconds in the original table.

LII
The Galactic Longitude of the EUVE source.

BII
The Galactic Latitude of the EUVE source.

Exposure
The effective exposure time, in seconds (s). Although the nominal lower limit for an exposure to be used in this catalog was 10 ks, in a small number of cases the effective exposure time was less than 10 ks because of the various corrections for telescope vignetting, and instrumental and telemetry dead times, so this parameter was given with a precision of kiloseconds in the original, as-published table.

Limit_Le_Count_Rate
The lower limit flag for the Lexan/B band count rate. If this parameter is set to '<', this indicates that the Lexan/B count rate quoted corresponds to a 2-sigma (90% confidence) upper limit, even though the catalog authors believe that the source was actually detected, albeit at a somewhat lower formal significance level, due to the often high and variable EUVE background.

Le_Count_Rate
The count rate, in ct/ks, in the Lexan/B Band. The pairs of bandpasses for the A and B scanners and for the DS are similar, although not identical, and the HEASARC has used the same parameters, called le_count_rate and al_count rate, for their count rates. Notice that the le_count_rate for Table 2 entries (rap_sample = 'scanner') is the count rate in the Scanners A and B Lexan/B band from 58 - 174 A, or 0.071 - 0.21 keV, while the le_count_rate for Table 4 entries (rap_sample = 'deep_survey') is the count rate in the DS Lexan/B band from 67 - 178 A, or 0.07 - 1.18 keV'.

Le_Count_Rate_Error
The rms uncertainty in the count rate in the Scanners A and B Lexan/B band (for entries with rap_sample = 'scanner') or in the DS Lexan/B band (for entries with rap_sample = 'deep_survey'), in ct/ks.

Limit_Al_Count_Rate
The lower limit flag for the Al/Ti/C (Scanner A and B) or the Al/C (Deep Survey) band count rate. If this parameter is set to '<', this indicates that the associated count rate quoted corresponds to a 2-sigma (90% confidence) upper limit, even though the catalog authors believe that the source was actually detected, albeit at a somewhat lower formal significance level, due to the often high and variable EUVE background.

Al_Count_Rate
The count rate, in ct/ks, in the Scanner Al/Ti/C or the DS Al/C band. The pairs of bandpasses for the A and B scanners and for the DS are similar, although not identical, and the HEASARC has used the same parameters, called le_count_rate and al_count rate, for their count rates. Notice that the al_count_rate for Table 2 entries (rap_sample = 'scanner') is the count rate in the Scanners A and B Al/Ti/C band from 156 - 234 A, or 0.053 - 0.079 keV, while the al_count_rate for Table 4 entries (rap_sample = 'deep_survey') is the count rate in the DS Al/C band from 157 - 364 A, or 0.034 - 0.079 keV.

Al_Count_Rate_Error
The rms uncertainty in the count rate in the Scanner Al/Ti/C band (for entries with rap_sample = 'scanner') or in the DS Al/C band (for entries with rap_sample = 'deep_survey'), in ct/ks.

Limit_Dag_Count_Rate
The lower limit flag for the Dagwood (Ti/Sb/Al) band count rate. If this parameter is set to '<', this indicates that the Dagwood count rate quoted corresponds to a 2-sigma (90% confidence) upper limit, even though the catalog authors believe that the source was actually detected, albeit at a somewhat lower formal significance level, due to the often high and variable EUVE background.

Dag_Count_Rate
The count rate, in ct/ks, in the Dagwood filter (Ti/Sb/Al) band. The bandpass for the Dagwood filter was 345 - 605 A, or 0.02 - 0.36 keV.

Dag_Count_Rate_Error
The rms uncertainty in the count rate in the Dagwood filter band, in ct/ks.

Limit_Tin_Count_Rate
The lower limit flag for the Tin (Sn/SiO) band count rate. If this parameter is set to '<', this indicates that the Tin band count rate quoted corresponds to a 2-sigma (90% confidence) upper limit, even though the catalog authors believe that the source was actually detected, albeit at a somewhat lower formal significance level, due to the often high and variable EUVE background.

Tin_Count_Rate
The count rate, in ct/ks, in the Tin (Sn/SiO) band. The bandpass for the Tin filter was 500 - 740 A, or 0.017 - 0.025 keV.

Tin_Count_Rate_Error
The rms uncertainty in the count rate in the Tin filter band, in ct/ks.

Qflag
This is a coded quality flag which has the following possible values:

              1: indicates a likely identification with supporting evidence as a
                  previously identified EUV source
              2: indicates that although the detection is statistically
                  significant, there was no other supporting evidence
              H: indicated no identification was found
              U: indicates that (1) the source has a strong ultraviolet continuum,
                  (2) the reported emission is outside the EUV bandpass, and
                  (3) is often referred to as "ultraviolet leak" (McDonald et al.,
                  1994AJ....108.1843M; Vedder et al., 1993, Proc. SPIE, 1742, 486)
                  In general, most of these sources are not included here but can
                  be found in Table A1 of the published version of the catalog.
  

Opt_Id_1
A plausible (optical, radio, EUV, X-ray, etc.) identification for the EUVE RAP source, or 'NOID' if there is no such identification. Some of the sources have two alternative identifications suggested for them in this catalog. Notice that, in such cases, the HEASARC has followed the original catalog and listed separate entries for each alternative identification. For example, the EUV source EUVE J0241-006 is listed twice, once with the suggested ID of NGC 1068, and a second time with the suggested ID of 84 Cet.

Opt_Id_2
An alternate name for the proposed counterpart to the EUVE RAP source.

Type
The spectral type (for normal stars and white dwarfs) or object class (for non-stellar sources or peculiar or unidentified sources) for the proposed counterpart to the EUVE RAP source, obtained by the catalog authors from SIMBAD, NED and/or the literature where available. In addition to the spectral types, the following object types were used:

           Object Type     Description

              BLL           BL Lac object
              blu           blue stellar object
              CV            cataclysmic variable
              Gal           galaxy
              PN            planetary nebula
              QSO           quasi-stellar object
              RadioS        radio source
              Star          star of unknown spectral type
              Sy            Seyfert galaxy
              Sy1           Type 1 Seyfert galaxy
              Sy2           Type 2 Seyfert galaxy
              UV            UV source
              V star        variable star of unknown spectral type
              WD            white dwarf of unknown spectral type
              X             X-ray source
  

Vmag
The V magnitude (usually) for the proposed counterpart to the EUVE RAP source, obtained by the catalog authors from SIMBAD, NED and/or the literature where available. For a small number of the sources the quoted magnitude is in a band other than the V band which is specified in the comments field.

Offset
The angular separation between the measured EUVE position and the identified source's position, in arcseconds.

Comments
Comments as discussed in section 4 of the published paper, and/or codes for selected references in the literature:

  Comments:

               FB = source was obstructed by a filter bar
               OA = source was off-axis
               PH = source was obstructed by a pinhole
           RS CVn = Binary of RS CVn type
            B Mag = quoted magnitude is in B not V band
            I Mag = quoted magnitude is in I not V band

  Catalog or literature reference cited:

             NED: NASA Extragalactic Database
             2EU: EUVE second catalog, Bowyer et al., 1996, Cat. <II/203>
            1RXS: ROSAT All Sky Survey, Voges et al., 1996, Cat. <IX/10>
             2RE: ROSAT Second All Sky Survey, Pye et al, 1995,
                   Cat. <J/MNRAS/274/1165>
            1WGA: White et al., 1995, ROSAT PSPC catalog, Cat. <IX/31>
             1ES: First Einstein Slew Survey, Elvis et al., 1992ApJS...80..257E
              2E: Second Einstein Soft X-ray Catalog, 1994, Cat. <IX/13>
             EXO: EXOSAT source
             L97: Lampton et al., 1997, Catalog of fainter EUVE detections,
                   Cat. <II/203>
             B97: Burleigh et al., 1997MNRAS.287..381B
             C98: Christian et al., 1998AJ....115..316C
             D80: Dressler, 1980. Cat. <VII/74>
             E93: Eggen, 1993AJ....106.1885E
             F98: Fleming, 1998ApJ...504..461F
             H98: Halpern et al., 1998PASP..110.1394H
             J95: Jefferies et al., 1995MNRAS.267..387J
             J98: Jensen et al., 1998AJ....116..414J
             K84: Kilkenny, 1984MNRAS.211..969K
           SPB96: Smith et al., 1996, Cat. <J/ApJS/91/129>
            WT91: Wroblewski & Torres, 1991, Cat. <J/A+AS/91/129>
            WT96: Wroblewski & Torres, 1996, Cat. <J/A+AS/115/481>
  

Rap_Sample
This parameter was created by HEASARC to differentiate entries from the 3 input tables merged to create this HEASARC database table. It is set to 'scanner' for entries from Table 2 which list count rates using EUVE Scanners A and B, to 'lw_scanner' for entries from Table 3 which list count rates using the Long-Wavelength Scanner C, and to 'deep_survey' for entries from Table 4 which list count rates using the EUVE Deep Survey telescope.

Class
The HEASARC Browse object classification, based on the value of the type parameter (q.v.).


Contact Person

Questions regarding the EUVERAP2 database table can be addressed to the HEASARC User Hotline.

Page Author: Browse Software Development Team
Last Modified: 8-Aug-2006