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J/A+A/363/517       Redshift from UBRI photometry method    (Mobasher+, 2000)

The effect of dust on photometric redshift measurement: a self-consistent technique. Mobasher B., Mazzei P. <Astron. Astrophys. 363, 517 (2000)> =2000A&A...363..517M
ADC_Keywords: Galaxies, photometry ; Photometry, UBVRI ; Redshifts Keywords: galaxies: evolution - galaxies: formation - galaxies: photometry - galaxies: starburst - cosmology: observations Abstract: A new method is developed for estimating photometric redshifts, using realistic template Spectral Energy Distributions (SEDs), extending over four decades in wavelength (i.e. from 0.05µm to 1mm). The template SEDs are constructed for four different spectral types of galaxies (elliptical, spiral, irregular and starburst), satisfying the following characteristics: a) they are normalised to produce the observed colours of galaxies at z∼0; b) incorporate the chemo-photometric spectral evolution of galaxies of different types, in agreement with the observations; c) allow treatment of dust contribution and its evolution with redshift, consistent with the spectral evolution models; d) include absorption and re-emission of radiation by dust and hence, realistic estimates of the far-infrared radiation; e) include correction for inter-galactic absorption by Lyman continuum and Lyman forest. Using these template SEDs, the photometric redshifts are estimated to an accuracy of Δz=0.11. The simultaneous and self-consistent modelling of both the photometric and chemical evolution of galaxies and the effect of dust, makes this technique particularly useful for high redshift galaxies. The effects on the estimated photometric redshifts, due to assumptions in the evolutionary population synthesis models, are investigated and discussed. Also, the degeneracy in the predicted photometric redshifts and spectral types are examined, using a simulated galaxy catalogue. File Summary:
FileName Lrecl Records Explanations
ReadMe 80 . This file table1.dat 78 73 The calibrating sample table1.tex 90 212 LaTeX version of table 1
See also: J/ApJ/513/34 : HDF photometric redshifts catalog (Fernandez-Soto+, 1999) Byte-by-byte Description of file: table1.dat
Bytes Format Units Label Explanations
1- 13 A13 --- Name HDF designation 15- 17 A3 --- n_Name Individual notes (1) 19- 20 I2 h RAh Right ascension (J2000) 22- 23 I2 min RAm Right ascension (J2000) 25- 29 F5.2 s RAs Right ascension (J2000) 31 A1 --- DE- Declination sign (J2000) 32- 33 I2 deg DEd Declination (J2000) 35- 36 I2 arcmin DEm Declination (J2000) 38- 42 F5.2 arcsec DEs Declination (J2000) 44- 48 F5.2 mag Imag I-band aperture magnitude in AB system 50- 54 F5.2 mag Rmag R-band aperture magnitude in AB system 56- 60 F5.2 mag Bmag B-band aperture magnitude in AB system 62- 66 F5.2 mag Umag U-band aperture magnitude in AB system 68- 72 F5.3 --- zspect Spectral redshift 74- 78 F5.3 --- zphot Photometric redshift
Note (1): Individual notes: 1: This galaxy is close to HDF3646+1408 (zspec=0.13). An aperture of 1.2" diameter is used for this object. 2: This galaxy is within 3" of another object (Lanzetta et al., 1997AJ....114.1337L). An aperture of 1.2" is used for this galaxy. 3: A spectroscopic redshift of 0.13 is found for this galaxy (Cowie, 1997ApJ...481L...9C). However, this object is close to another galaxy (HDF3646+1405) with zspec=0.96 and lies within 1" of a brighter source. It is likely that the spectroscopic redshift of this galaxy is in error. Lanzetta et al. (1997AJ....114.1337L) estimate a photometric redshift of 1.2 for this object compared to our value of 0.675 (when using 1.2" aperture diameter). 4: This galaxy lies within 1" of a slightly brighter galaxy with no available redshift. Lanzetta et al. (1997AJ....114.1337L) estimate a photometric redshift of 0.76 for this object compared to our estimate of 0.925. It is likely that the spectroscopic redshift of this object is in error due to confusion with an overlapping source. 5: This galaxy is undetected in the U-band and shows a very red B-I colour. It is likely that intervening absorbers have affected its SED. 6: This object shows a very complex morphology with a disk galaxy a few arcsec to its southwest (Lowenthal et al., 1997ApJ...481..673L). An aperture of 1.2" diameter is used for this galaxy. 7: An aperture of 1.2" diameter is used for this galaxy due to close companions. 8: These objects are identified as UV `drop-outs' in Lowenthal et al. (1997ApJ...481..673L). We assume U=28.01mag. An effective aperture of 1.2" diameter is used. 9: This galaxy had been given a wrong spectroscopic redshift of 2.845. Its spectroscopic redshift was subsequently measured to be 2.008 (Lanzetta et al., 1997AJ....114.1337L; Dickinson, 1998, in The Hubble Deep Field. Cambridge University Press. Cambridge. p. 219.).
Acknowledgements: Bahram Mobasher
(End) Patricia Bauer [CDS] 05-Dec-2000
The document above follows the rules of the Standard Description for Astronomical Catalogues.From this documentation it is possible to generate f77 program to load files into arrays or line by line

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