## Content

02 July 2001

CALOBS contains several versions of the ultraviolet (UV) and optical spectra of the fundamental flux standards used for HST calibrations. Some of these files contain the original data obtained from different sources (UV: VOYAGER2 or IUE; optical: Oke, Tapia or Stone; or STIS), while others contain corrected or updated versions. Updates to the flux distributions are indicated by file names with the same root name but incremental version number. The earlier versions are retained for comparison purposes. All files are in machine independent binary FITS table format. Information about the pedigree of a given spectrum is in the header of the FITS file, which can be read with the IRAF hedit task or by mrdfits.pro in IDL.

The table below lists the Oke's faint spectrophotometric standards. In total, Oke supplied 30 spectra, which include 5 more than his 1990 publication (Oke 1990). The CDBS name listed in column 4 of the table is the most recently updated version of the original Oke spectra on the white dwarf scale, corrected for spectral shape and absolute photometry, and covering the 3200 to 9200 Angstrom range. See Bohlin (1996) and references therein for details. The CDBS name listed in column 5 of the table is the most updated version of the IUE spectra on the white dwarf scale (see Bohlin 1996 for details). Those spectra have been used to create the CALSPEC spectra of HST standards and can also be used in the calibration of ground based data.

See Bohlin, Dickinson, and Calzetti (2001) for a description of the two most recent CALOBS additions: BPM16274_STIS_001 and G191B2B_PURE_STIS_001.

List of Oke's optical faint spectrophotometric standards:

   NAME         RA(2000)    DECLINATION(2000)   CDBS NAME        CDBS NAME
(1)            (2)              (3)             (4)              (5)

G158-100      00 33 54.32     -12 07 57.1     G158_100_011
GD50          03 48 50.06     -00 58 30.4     GD50_013         GD50_012
SA95-42       03 53 43.67     -00 04 33.0     SA95_42_005
HZ 4          03 55 21.70     +09 47 18.7     HZ4_019          HZ4_018
LB227         04 09 28.76     +17 07 54.4     LB227_008        LB227_007

HZ 2          04 12 43.51     +11 51 50.4     HZ2_014          HZ2_013
G191B2B       05 05 30.62     +52 49 54.0     G191B2B_019      G191B2B_018
G193-74       07 53 27.40     +52 29 35.7     G193_74_008
BD+75D325     08 10 49.31     +74 57 57.5     BD_75D325_011    BD_75D325_010
AGK+81D266    09 21 19.06     +81 43 28.6     AGK_81D266_010   AGK_81D266_009

GD108         10 00 47.33     -07 33 31.2     GD108_012        GD108_011
FEIGE 34      10 39 36.71     +43 06 10.1     FEIGE34_020      FEIGE34_019
HD 93521      10 48 23.51     +37 34 12.8     HD93521_014      HD93521_013
HZ 21         12 13 56.42     +32 56 30.8     HZ21_015         HZ21_014
FEIGE 66      12 37 23.55     +25 04 00.3     FEIGE66_017      FEIGE66_016

FEIGE 67      12 41 51.83     +17 31 20.5     FEIGE67_016      FEIGE67_015
G60-54        13 00 09.53     +03 28 55.7     G60_54_007
HZ 44         13 23 35.37     +36 08 00.0     HZ44_018         HZ44_017
GRW+70D5824   13 38 51.77     +70 17 08.5     GRW_70D5824_012  GRW_70D5824_011
BD+33D2642    15 51 59.86     +32 56 54.8     BD_33D2642_016   BD_33D2642_015

G138-31       16 27 53.59     +09 12 24.5     G138_31_009
G24-9         20 13 56.05     +06 42 55.2     G24_9_009
LDS749B       21 32 15.75     +00 15 13.6     LDS749B_011      LDS749B_010
BD+28D4211    21 51 11.07     +28 51 51.8     BD_28D4211_021   BD_28D4211_020
G93-48        21 52 25.33     +02 23 24.3     G93_48_009       G93_48_008

BD+25D4655    21 59 39.3      +26 25 42       BD_25D4655_007   BD_25D4655_006
NGC 7293      22 29 38.46     -20 50 13.3     NGC7293_010      NGC7293_009
LTT 9491      23 19 34.98     -17 05 29.8     LTT9491_010      LTT9491_009
FEIGE 110     23 19 58.39     -05 09 56.1     FEIGE110_020     FEIGE110_019
GD 248        23 26 06.69     +16 00 21.4     GD248_010


Note: The unit of flux in all files is erg s-1 cm-2 A-1.

REFERENCES:

Bohlin, R.C., 1996, AJ, 111, 1743.
Bohlin, R.C., Dickinson, M. E., & Calzettti, D. 2001, AJ, in press.
Oke, J.B. 1990, AJ, 99, 1621.


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To the CALOBS data (historical data, for current and more accurate data, please go to the CALSPEC page)