J/MNRAS/399/2231 SDSS DR5 BALQSO catalog (Scaringi+, 2009)
Classifying broad absorption line quasars:
metrics, issues and a new catalogue constructed from SDSS DR5.
Scaringi S., Cottis C., Knigge C., Goad M.
<Mon. Not. R. Astron. Soc. 399, 2231 (2009)>
=2009MNRAS.399.2231S 2009MNRAS.399.2231S
ADC_Keywords: Surveys ; QSOs ; Redshifts
Keywords: catalogue - surveys - quasar: absorption lines -
Abstract:
We apply a recently developed method for classifying broad absorption
line quasars (BALQSOs) to the latest QSO catalogue constructed from
Data Release 5 of the Sloan Digital Sky Survey. Our new hybrid
classification method combines the power of simple metrics, supervised
neural networks and visual inspection. The resulting BALQSO catalogue
is both more complete and more robust than all previous BALQSO
catalogues, containing 3552 sources selected from a parent sample of
28421 QSOs in the redshift range 1.7<z<4.2. This equates to a raw BAL
QSO fraction of 12.5%. In the process of constructing a robust
catalogue we shed light on the main problems encountered when dealing
with BALQSO classification, in particular when the astronomical
objects in question do not yet have a formal definition as is the case
for BALQSOs. This introduces some subjectivity on what is meant by
BALQSO, and because of this we also provide meta-data of our
catalogue, comprising our whole parent sample which can be used to
quickly isolate and explore various sub-samples.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
catalog.dat 68 28421 DR5 meta-catalogue (1.7<z<4.2)
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See also:
VII/252 : SDSS-DR5 quasar catalog (Schneider+, 2007)
J/AJ/133/313 : AGN from RASS and SDSS DR5 (Anderson+, 2007)
J/ApJ/685/773 : X-Ray-UV relations in SDSS DR5 QSOs (Gibson+, 2008)
http://www.sdss.org : SDSS Home Page
Byte-by-byte Description of file: catalog.dat
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Bytes Format Units Label Explanations
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1- 18 A18 --- SDSS SDSS DR5 Designation HHMMSS.ss+DDMMSS.s (J2000)
20- 29 F10.6 deg RAdeg Right Ascenscion in decimal degrees, J2000
31- 40 F10.6 deg DEdeg Declination in decimal degrees, J2000
42- 47 F6.4 --- z Redshift
49- 55 F7.3 mag iMAG Absolute i magnitude
57 I1 --- lz [0/1] Low-z Quasar (color selection only)
target flag (1)
59 I1 --- hz [0/1] High-z Quasar (color selection only)
target flag (1)
61- 64 I4 km/s BI Balnicity Index taken from Gibson et al.,
2008, Cat. J/ApJ/685/773 (2)
66 I1 --- LVQ [0/1] BALQSO tag from "Learning Vector
Quantization" network (Kohonen) (1)
68 I1 --- BAL [0/1] Final BALQSO tag using
hybrid-LVQ method (1)
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Note (1): BAL indicator flag is:
0 = no BAL (broad absorption lines)
1 = BAL (broad absorption lines)
Note (2): Sources with BI>0 are considered to have BAL (broad absorption lines).
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Acknowledgements:
Simone Scaringi, simo(at)astro.soton.ac.uk
References:
Scaringi et al., Paper I 2008MNRAS.390.1339S 2008MNRAS.390.1339S
(End) Simone Scaringi [Univ. Southampton], Patricia Vannier [CDS] 03-Sep-2009