2009MNRAS.399.2231S


Query : 2009MNRAS.399.2231S

2009MNRAS.399.2231S - Mon. Not. R. Astron. Soc., 399, 2231-2238 (2009/November-2)

Classifying broad absorption line quasars: metrics, issues and a new catalogue constructed from SDSS DR5.

SCARINGI S., COTTIS C.E., KNIGGE C. and GOAD M.R.

Abstract (from CDS):

We apply a recently developed method for classifying broad absorption line quasars (BALQSOs) to the latest quasi-stellar object (QSO) catalogue constructed from Data Release 5 of the Sloan Digital Sky Survey. Our new hybrid classification scheme combines the power of simple metrics, supervised neural networks and visual inspection. In our view, 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 BALQSO fraction of 12.5 per cent.

In the process of constructing a robust catalogue, we shed light on the main problems encountered when dealing with BALQSO classification, many of which arise due to the lack of a proper physical definition of what constitutes a BAL. This introduces some subjectivity in what is meant by the term BALQSO, and because of this, we also provide all of the meta-data used in constructing our catalogue, for every object in the parent QSO sample. This makes it easy to quickly isolate and explore subsamples constructed with different metrics and techniques. By constructing composite QSO spectra from subsamples classified according to the meta-data, we show that no single existing metric produces clean and robust BALQSO classifications. Rather, we demonstrate that a variety of complementary metrics are required at the moment to accomplish this task. Along the way, we confirm the finding that BALQSOs are redder than non-BALQSOs and that the raw BALQSO fraction displays an apparent trend with signal-to-noise ratio steadily increasing from 9 per cent in low signal-to-noise ratio data up to 15 per cent.


Abstract Copyright: © 2009 The Authors. Journal compilation © 2009 RAS

Journal keyword(s): catalogues - surveys - quasars: absorption lines

VizieR on-line data: <Available at CDS (J/MNRAS/399/2231): catalog.dat>

Simbad objects: 14

goto Full paper

goto View the references in ADS

Number of rows : 14
N Identifier Otype ICRS (J2000)
RA
ICRS (J2000)
DEC
Mag U Mag B Mag V Mag R Mag I Sp type #ref
1850 - 2023
#notes
1 SDSS J000006.53+003055.2 QSO 00 00 06.5328876216 +00 30 55.216523484   20.61 20.37     ~ 18 0
2 SDSS J000008.13+001634.6 QSO 00 00 08.1399034776 +00 16 34.706651052   20.35 20.03     ~ 18 0
3 SDSS J000009.38+135618.4 QSO 00 00 09.3817623168 +13 56 18.459059496   19.06 18.63     ~ 29 0
4 [VV2006] J000009.4-102752 QSO 00 00 09.4280758656 -10 27 51.856637076   19.31 19.11     ~ 25 0
5 SDSS J000013.80-005446.8 QSO 00 00 13.8036978288 -00 54 46.808320608   20.34 20.10     ~ 18 0
6 SDSS J000014.82-011030.6 QSO 00 00 14.8236566760 -01 10 30.765992088   19.50 19.31     ~ 17 0
7 SDSS J000015.47+005246.8 QSO 00 00 15.4839256344 +00 52 46.867694340   19.74 19.55     ~ 17 0
8 SDSS J000030.37-002732.4 QSO 00 00 30.3827321640 -00 27 32.445198720   20.39 20.17     ~ 16 0
9 SDSS J000038.65+011426.3 QSO 00 00 38.6677373592 +01 14 26.272927356   20.50 20.46     ~ 16 0
10 2SLAQ J000038.99-001803.9 QSO 00 00 39.0015522264 -00 18 03.964683384   19.93 19.63     ~ 29 0
11 SDSS J002440.99+004557.7 QSO 00 24 40.9938696816 +00 45 57.756187440   20.86 20.54     ~ 22 0
12 [VV2006] J010858.0+005115 QSO 01 08 58.0262519928 +00 51 14.593946400   20.32 19.91     ~ 30 0
13 SDSS J213438.96+000953.8 QSO 21 34 38.9651165904 +00 09 53.775151128   19.24 19.10     ~ 25 0
14 SDSS J235233.86-001844.1 QSO 23 52 33.8608026960 -00 18 44.293680684   20.63 20.35     ~ 18 0

To bookmark this query, right click on this link: simbad:objects in 2009MNRAS.399.2231S and select 'bookmark this link' or equivalent in the popup menu


2023.01.28-00:35:14

© Université de Strasbourg/CNRS

    • Contact