CDROM/AJ/V106/P0426
QSO Candidates and Halo Stars (Tytler+ 1993)
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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
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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 yyyymm-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.
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(End)
Lee Brotzman [ADS] 08Mar-1995