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J/ApJS/135/41 Spectroscopic and photometric redshifts (Fernandez-Soto+, 2001)
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On the compared accuracy and reliability of spectroscopic and
photometric redshift measurements.
Fernandez-Soto A., Lanzetta K.M., Chen H.-W., Pascarelle S.M., Yahata N.
<Astrophys. J. Suppl. Ser. 135, 41 (2001)>
=2001ApJS..135...41F
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ADC_Keywords: Galaxy catalogs ; Redshifts
Keywords: cosmology: observations - galaxies: distances and redshifts -
methods: data analysis - techniques: photometric -
techniques: spectroscopic
Abstract:
We present a comparison between the catalog of spectroscopic redshifts
in the Hubble Deep Field (HDF) recently published by Cohen and
collaborators (2000, cat. <J/ApJ/538/29>) and the redshifts that our
group (Fernandez-Soto et al., 1999, Cat. <J/ApJ/513/34>) has measured
for the same objects using photometric techniques. This comparison is
performed in order to fully characterize the errors associated with
the photometric redshift technique. The compilation of spectroscopic
redshifts incorporates previously published results, corrections to
previously published wrong values, and new data, and it includes over
140 objects in the HDF proper. It represents the deepest, cleanest,
most complete spectroscopic catalog ever compiled.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 87 6 Objects with double cross identifications in the
catalogs (<J/ApJ/538/29> and <J/ApJ/513/34>)
table2.dat 86 146 Comparison of both catalogs
table3.dat 76 10 *Objects in Cohen et al. (2000, Cat. <J/ApJ/538/29>)
with no spectroscopic redshift
table6.dat 88 10 Properties of the objects with discordant redshifts
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Note on table3.dat: One object in Table 10 in C00 (HDF 36378_1235) does not
enter our definition of the "HDF proper" area.
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See also:
J/ApJ/513/34 : HDF photometric redshifts catalog (Fernandez-Soto+, 1999)
J/ApJ/538/29 : HDF-N Caltech faint galaxy redshift survey. X. (Cohen+, 2000)
Byte-by-byte Description of file: table1.dat table2.dat table3.dat
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Bytes Format Units Label Explanations
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1- 2 I2 h RACh Right Ascension (J2000) from Cohen et al.,
2000, Cat. <J/ApJ/538/29>, C00
4- 5 I2 min RACm Right Ascension (J2000) from C00
7- 11 F5.2 s RACs Right Ascension (J2000) from C00
12 A1 --- DEC- Declination sign (J2000) from C00
14- 15 I2 deg DECd Declination (J2000) from C00
17- 18 I2 arcmin DECm Declination (J2000) from C00
20- 23 F4.1 arcsec DECs Declination (J2000) from C00
24 A1 --- Note [bc] Note for objects in table3.dat (1)
25- 29 F5.3 --- zspec ? Spectroscopic redshift from C00
31- 35 F5.2 mag Rmag R band magnitude from C00
37- 40 I4 --- [FLY99] ? Identification number of Fernandez-Soto
et al., 1999, Cat. <J/ApJ/513/34>, FLY99
42- 43 I2 h RAh Right Ascension (J2000) from FLY99
45- 46 I2 min RAm Right Ascension (J2000) from FLY99
48- 52 F5.2 s RAs Right Ascension (J2000) from FLY99
54 A1 --- DE- Declination sign (J2000) from FLY99
55- 56 I2 deg DEd Declination (J2000) from FLY99
58- 59 I2 arcmin DEm Declination (J2000) from FLY99
61- 65 F5.2 arcsec DEs Declination (J2000) from FLY99
67- 70 F4.2 --- zphot Photometric redshift from FLY99
72- 76 F5.2 mag ABmag AB (8140{AA}) band magnitude from FLY99
78- 82 F5.2 --- dz/1+z ? Photometric redshift accuracy statistic (2)
84 A1 --- f_dz/1+z Flag on Delz/1+z (3)
85- 87 F3.1 arcsec Offset ? Distance between the position in C00 and
FLY99 (only in table1.dat)
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Note (1): Individual notes in table3.dat:
b: Two objects in our catalog correspond to one position as listed by C00.
c: Not an object in FLY99. See the text for an explanation
Note (2): Equal to the difference between the two redshift determinations
(zphot-zspec) divided by (1+z).
Note (3):
+ = objects with possible double identifications listed in Table 1;
* = objects which are discussed in more detail in Sections 4 and 5.
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Byte-by-byte Description of file: table6.dat
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Bytes Format Units Label Explanations
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1- 14 A14 --- HDF HDF designation
15 A1 --- n_HDF [*] Note on HDF 36450_1251 (1)
17- 21 F5.3 --- zspec Spectroscopic redshift
23- 27 F5.2 mag Rmag R magnitude
29 I1 --- q_zspec Spectroscopic quality flag (2)
31- 34 F4.2 --- zphot Photometric redshift
36- 88 A53 --- Note Notes
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Note (1): *: This object is not greater than 4{sigma} discordant,
but strong evidence points to the spectroscopic redshift being in
error (see text for details).
Note (2): the qualities are defined in the Note (1) of C00 (J/ApJ/538/29):
1: Multiple features, {sigma}(z)<=0.002/feature
2: Multiple features, {sigma}(z)<=0.004/feature
3: Multiple features, faint, id uncertain, {sigma}(z) small 75% of
time, and wildly off 25% of time
4: One emission line only, solid, assume 3727{AA}
5: One emission line only, reality uncertain, assume 3727{AA}
6: Multiple features, at least one broad emission line
7: Only one broad emission line, assumed to be 2800{AA}
8: Single break, assumed to be 4000{AA} break
9: Single strong absorption feature, assumed to be 2800{AA}
because of shape of continuum
0: no redshift
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History:
From electronic version of the journal
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(End) Greg Schwarz [AAS], Patricia Bauer [CDS] 30-Aug-2001