[CBS2017] ALH2L323 , the SIMBAD biblio

2017MNRAS.472.2085C - Mon. Not. R. Astron. Soc., 472, 2085-2106 (2017)

ELDAR, a new method to identify AGN in multi-filter surveys: the ALHAMBRA test case.

CHAVES-MONTERO J., BONOLI S., SALVATO M., GREISEL N., DIAZ-GARCIA L.A., LOPEZ-SANJUAN C., VIIRONEN K., FERNANDEZ-SOTO A., POVIC M., ASCASO B., ARNALTE-MUR P., MASEGOSA J., MATUTE I., MARQUEZ I., CENARRO A.J., ABRAMO L.R., EDEROCLITE A., ALFARO E.J., MARIN-FRANCH A., VARELA J. and CRISTOBAL-HORNILLOS D.

Abstract (from CDS):

We present ELDAR, a new method that exploits the potential of medium- and narrow-band filter surveys to securely identify active galactic nuclei (AGN) and determine their redshifts. Our methodology improves on traditional approaches by looking for AGN emission lines expected to be identified against the continuum, thanks to the width of the filters. To assess its performance, we apply ELDAR to the data of the ALHAMBRA (Advance Large Homogeneous Area Medium Band Redshift Astronomical) survey, which covered an effective area of 2.38 deg2 with 20 contiguous medium-band optical filters down to F814W ≃ 24.5. Using two different configurations of ELDAR in which we require the detection of at least two and three emission lines, respectively, we extract two catalogues of type-I AGN. The first is composed of 585 sources (79 per cent of them spectroscopically unknown) down to F814W = 22.5 at zphot > 1, which corresponds to a surface density of 209 deg–2. In the second, the 494 selected sources (83 per cent of them spectroscopically unknown) reach F814W = 23 at zphot > 1.5, for a corresponding number density of 176 deg–2. Then, using samples of spectroscopically known AGN in the ALHAMBRA fields, for the two catalogues we estimate a completeness of 73 per cent and 67 per cent, and a redshift precision of 1.01 per cent and 0.86 per cent (with outliers fractions of 8.1 per cent and 5.8 per cent). At z > 2, where our selection performs best, we reach 85 per cent and 77 per cent completeness and we find no contamination from galaxies.

Abstract Copyright: 2017 The Authors Published by Oxford University Press on behalf of the Royal Astronomical Society

Journal keyword(s): methods: data analysis - techniques: photometric - surveys - galaxies: active - galaxies: distances and redshifts - quasars: emission lines - galaxies: active - galaxies: distances and redshifts

VizieR on-line data: <Available at CDS (J/MNRAS/472/2085): alh2l.dat alh3l.dat>

Nomenclature: alh21.dat: [CBS2017] ALH2LNNN (Nos ALH2L000-ALH2L584). alh31.dat: [CBS2017] ALH3LNNN (Nos ALH3L000-ALH3L493).

Simbad objects: 815

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