CDROM/AJ/V106/P0426 QSO Candidates and Halo Stars (Tytler+ 1993) ================================================================================ Lick Slit Spectra of Thirty-Eight Objective Prism Quasar Candidates and Low Metallicity Halo Stars David Tytler, Xiao-Ming Fan, Vesa T. Junkkarinen, & Ross D. Cohen <1993, AJ, 106, 426> =1993AJ....106..426T ================================================================================ Abstract: We present Lick Observatory slit spectra of 38 objects which were claimed to have pronounced ultraviolet excess and emission lines. Zhan & Chen selected these objects by eye from a UK Schmidt telescope IIIaJ objective prism plate of a field at 0 h 0.0 deg (l ~= 98 deg, b ~= -60 deg). We concentrate on m(J) ~= 18-19 objects which Zhan and Chen (ZC) thought were most likely to be quasistellar objects (QSOs) at redshift z(em) >= 2.8. Most of our spectra have FWHM spectral resolutions of about 4 A, and relatively high S/N of about 10-50, although some have FWHM ~= 15 A or lower S/N. We find eleven QSOs, four galaxies at z ~= 0.1, twenty-two stars and one unidentified object with a low S/N spectrum. The ZC lists are found to contain many QSOs at low z but few at high z, as expected. Of eleven objects which ZC suggested were QSOs with z(prism) <= 2.8, eight (73%) are QSOs. But only three of twenty-five candidates with z(prism) >= 2.8 are QSOs, and only two (8%) of these are at z >= 2.8. Unfortunately, the ZC prism redshifts are often incorrect: only five of the eleven QSOs are at redshifts similar to z(prism). Six of the QSOs show absorption systems, including Q0000+027A with a relatively strong associated C IV absorption system, and Q0008+008 (V ~= 18.9) with a damped Ly alpha system with an HI column density of 10^21 cm^-2. The stars include a wide variety of spectral types. There is one new DA 4 white dwarf at 170 pc, one sdB at 14 kpc, and three M stars. The rest are of types F, G, and K. We have measured the equivalent widths of the Ca II K line, the G band, and the Balmer lines in ten stars with the best spectra, and we derive metallicities. Seven of them are in the range -2.5 <= [Fe/H] <= -1.7, while the others are less metal poor. If the stars are dwarfs, then they are at distances of 1 to 7 kpc, but if they are giants, typical distances will be about 10 kpc. File Summary: -------------------------------------------------------------------------------- File Name Lrecl Records Explanations -------------------------------------------------------------------------------- table1.dat 57 40 Journal of observations table1.tex 80 78 TeX version of table1.dat table2.dat 104 38 Summary of spectra table2.tex 126 104 TeX version of table2.dat table3.dat 74 40 Magnitudes and spectral indices table3.tex 95 94 TeX version of table3.dat table5.dat 88 52 Emission lines table5.tex 71 182 TeX version of table5.dat table6.dat 52 39 Major absorption lines in the QSO spectra table6.tex 78 85 TeX version of table6.dat -------------------------------------------------------------------------------- Comments for file: table1.dat -------------------------------------------------------------------------------- Table 1 contains the journal of observations, with the instrumental setup, wavelength range and integration time. The reference is also given to the Zhan and Chen paper which contains the object coordinates, magnitude and finding chart. Note that their charts have East to the right, and that the English translation of ZC3 lacks charts, while for the other papers the charts are often better in the translation. -------------------------------------------------------------------------------- Byte-by-byte Description of file: table1.dat -------------------------------------------------------------------------------- Bytes Format Units Label Explanations -------------------------------------------------------------------------------- 1-10 A10 --- Object Object designation 11 1X --- --- Blank 12-21 A10 --- Date Observation date, U.T., format yyyy-mm-dd 22-23 2X --- --- Blank 24-27 I4 s Time Integration time 28-29 2X --- --- Blank 30 A1 --- Setup [ABC] Instrumental setup (Section 2 of paper) 31-32 2X --- --- Blank 33-41 A9 --- Range *Wavelength range 42-43 2X --- --- Blank 44-52 A9 --- C_Range Red wavelength range for setup C 53-54 2X --- --- Blank 55-57 A3 --- Ref *Zhan and Chen reference -------------------------------------------------------------------------------- Notes for file: table1.dat -------------------------------------------------------------------------------- Range: Wavelength range. For setup A and B (UV Schmidt camera) this is the total range. For setup C (Kast double spectrograph) this is the blue range. The format can also be read as (I4,1X,I4) where the two integers are the minimum and maximum wavelengths in Angstroms, respectively. Ref: Zhan and Chen reference: ZC1 Zhan, Y., & Chen, J-S. 1987, AcApSn, 7, 99; Trans. in Chin.A.Ap., 11, 191 ZC2 Zhan, Y., & Chen, J-S. 1987, AcApSn, 7, 203; Trans. in Chin.A.Ap., 11, 299 ZC3 Zhan, Y., & Chen, J-S. 1989, AcApSn, 9, 37; Trans. in Chin.A.Ap., 13, 139 ZC4 Zhan, Y., & Chen, J-S. 1989, AcApSn, 9, 147; Trans. in Chin.A.Ap., 13, 321 -------------------------------------------------------------------------------- Byte-by-byte Description of file: table2.dat -------------------------------------------------------------------------------- Bytes Format Units Label Explanations -------------------------------------------------------------------------------- 1-10 A10 --- Object Object designation 11 1X --- --- Blank 12-15 F4.2 --- Z_ZC []? Objective prism redshift from ZC refs 16-17 2X --- --- Blank 18 I1 --- Q_ZC Reliability index Q from the ZC references 19-20 2X --- --- Blank 31-33 A13 --- Type *Stellar type 34-40 F7.4 --- Z []? Redshift 41-42 2X --- --- Blank 43-104 A62 --- Lines Spectral lines -------------------------------------------------------------------------------- Notes for file: table2.dat -------------------------------------------------------------------------------- Type: Stellar type. The first is from the spectral features and the second, in parentheses, is from (B-V)o. -------------------------------------------------------------------------------- Comments for file: table3.dat -------------------------------------------------------------------------------- Table 3 contains the estimated magnitudes from the slit spectra. These magnitudes are highly uncertain because they are derived from narrow slit spectra. Section 3.2 of the printed paper discusses the data reduction for the slit magnitudes in detail. Section 4.1 discusses the equivalent width measurements, HP, KP', and GP. -------------------------------------------------------------------------------- Byte-by-byte Description of file: table3.dat -------------------------------------------------------------------------------- Bytes Format Units Label Explanations -------------------------------------------------------------------------------- 1-10 A10 --- Object Object designation 11 1X --- --- Blank 12 A1 --- Note *[AB] Note flag 12-17 F6.2 mag B_J *B(J) magnitude from ZC references 18-24 F7.2 mag U []? U magnitude, highly uncertain 25-31 F7.2 mag B B magnitude, highly uncertain 32-38 F7.2 mag V V magnitude, highly uncertain 39-44 F6.2 mag B-V_o (B-V)o color, highly uncertain 45-50 F6.2 mag B-V *[]? (B-V) color estimate from Balmer line index HP 51-56 F6.2 mag Del_B-V []? Slit (B-V) minus HP index (B-V) 57-62 F6.2 0.1nm HP *[]? Balmer line index, HP 63-68 F6.2 0.1nm KP *[]? The index KP' 69-74 F6.2 0.1nm GP *[]? The G-band (CH) index, GP -------------------------------------------------------------------------------- Notes for file: table3.dat -------------------------------------------------------------------------------- Note: Note flag: 'A' for magnitudes measured from Setup A spectrum, and likely to be systematically too faint; 'B' for magnitudes measured from Setup B spectrum. B_J: B(J) magnitude from ZC references, obtained from image sizes on a direct Schmidt plate. B-V: (B-V) color estimated from the Balmer line index HP using: (B-V)o = 0.962 - 0.292HP + 0.036HP^2 HP: Balmer line index, HP = -0.120+0.5Halpha+0.555Hgamma, which is the average of the measured equivalent width of Halpha, and an estimate of that width based on the measured equivalent width of Hgamma. KP: The index KP', the Ca II K equivalent width measured in the 18 A interval, corrected for interstellar Ca II K absorption by subtracting 0.22 A. GP: The G-band (CH) index, GP, the equivalent width in the 15 A band around 4300 A. -------------------------------------------------------------------------------- Comments for file: table5.dat -------------------------------------------------------------------------------- Table 5 contains the wavelength and observed frame equivalent widths for the QSO and galaxy emission lines. Redshifts were weighted by the line equivalent widths. Individual cases are discussed in Section 6, NOTES ON INDIVIDUAL OBJECTS, in the printed paper. -------------------------------------------------------------------------------- Byte-by-byte Description of file: table5.dat -------------------------------------------------------------------------------- Bytes Format Units Label Explanations -------------------------------------------------------------------------------- 1-10 A10 --- Object *Object designation 11 1X --- --- Blank 12-17 F6.4 --- Z Mean emission redshift 18-19 2X --- --- Blank 20-32 A13 --- Ion Ion 33-41 F9.2 0.1nm Lam_lab Laboratory vacuum wavelength 42 A1 --- u_Lam_lab Uncertainty in one case, G-band for 0005+003 43-49 F7.1 0.1nm Lam_obs Observed wavelength 50-55 F6.0 0.1nm W_obs *Observed frame equivalent width 56-63 F8.4 --- Z_em Redshift, z(em) 64 1X --- --- Blank 64-88 A25 --- Comment *Comments -------------------------------------------------------------------------------- Notes for file: table5.dat -------------------------------------------------------------------------------- Object: Object designation, if this field is blank the emission line fields (all except the mean redshift in bytes 12-17 and the comments in bytes 65-88) are a continuation of the data for the previous object. W_obs: Observed frame equivalent width. All values have a decimal point, so that they will be read correctly by a computer program, but some of the values were originally integers. Comment: Comments. The comment "see notes" refers to Section 6 of the printed paper. -------------------------------------------------------------------------------- Byte-by-byte Description of file: table6.dat -------------------------------------------------------------------------------- Bytes Format Units Label Explanations -------------------------------------------------------------------------------- 1-10 A10 --- Object Object designation 11-12 2X --- --- Blank 13-14 I2 --- LineNo Seq. no. counting the line for this object 15-22 F8.1 0.1nm Lam_obs []? Observed vacuum wavelength 23 A1 --- n_Lam_obs *[d] Wavelength note flag 24-28 F5.1 0.1nm W_obs []? Observed equivalent width 29-30 2X --- --- Blank 31-36 A6 --- Line Line identification 37-41 F5.0 0.1nm Lam_lab []? Laboratory wavelength 42-43 2X --- --- Blank 44-45 A2 --- Note *[bc] Note flags 46-47 2X --- --- Blank 48-52 F5.3 --- Z_abs []? Absorption redshift -------------------------------------------------------------------------------- Notes for file: table6.dat -------------------------------------------------------------------------------- n_Lam_obs: Wavelength note flag, 'd' in one case only (line 0 of object 0010-002B), meaning this line was seen by reference ZC2 (see notes for table1.dat) Note: Note flags: 'b' Blended with C IV (1550 A); 'c' see individual notes in section 6 of the printed paper. -------------------------------------------------------------------------------- ================================================================================ (End) Lee Brotzman [ADS] 08-Mar-1995