A Method to improve line flux and redshift measurements with narrowband filters

Autor: Johannes Zabl, Bo Milvang-Jensen, L. A. M. Tasca, Kim K. Nilsson, Wolfram Freudling, O. Le Fevre, Johan P. U. Fynbo, Palle Møller
Přispěvatelé: Laboratoire de Physique Statistique de l'ENS (LPS), Université Paris Diderot - Paris 7 (UPD7)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Centre National de la Recherche Scientifique (CNRS)-Fédération de recherche du Département de physique de l'Ecole Normale Supérieure - ENS Paris (FRDPENS), École normale supérieure - Paris (ENS Paris), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS)-École normale supérieure - Paris (ENS Paris), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS), Department of Oncology 54B1, Herlev and Gentofte Hospital, Dark Cosmology Centre (DARK), Niels Bohr Institute [Copenhagen] (NBI), Faculty of Science [Copenhagen], University of Copenhagen = Københavns Universitet (KU)-University of Copenhagen = Københavns Universitet (KU)-Faculty of Science [Copenhagen], University of Copenhagen = Københavns Universitet (KU)-University of Copenhagen = Københavns Universitet (KU), Laboratoire d'Astrophysique de Marseille (LAM), Aix Marseille Université (AMU)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS), European Project: 648179,H2020,ERC-2014-CoG,ConTExt(2015), European Project: 278202,EC:FP7:ERC,ERC-2011-StG_20101014,EGGS(2011), Fédération de recherche du Département de physique de l'Ecole Normale Supérieure - ENS Paris (FRDPENS), École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS)-École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS), University of Copenhagen = Københavns Universitet (UCPH)-University of Copenhagen = Københavns Universitet (UCPH)-Faculty of Science [Copenhagen], University of Copenhagen = Københavns Universitet (UCPH)-University of Copenhagen = Københavns Universitet (UCPH)
Jazyk: angličtina
Rok vydání: 2016
Předmět:
FOS: Physical sciences
Context (language use)
Astrophysics
Astrophysics::Cosmology and Extragalactic Astrophysics
01 natural sciences
Narrowband
Band-pass filter
Methods: observational
Galaxies: distances and redshifts
0103 physical sciences
010303 astronomy & astrophysics
Instrumentation and Methods for Astrophysics (astro-ph.IM)
Line (formation)
Physics
Galaxies: star formation
010308 nuclear & particles physics
Galaxies: high-redshift
Astronomy and Astrophysics
Filter (signal processing)
Galaxies: photometry
Astrophysics - Astrophysics of Galaxies
Redshift
Computational physics
Wavelength
Space and Planetary Science
Astrophysics of Galaxies (astro-ph.GA)
H-alpha
[PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph]
Astrophysics - Instrumentation and Methods for Astrophysics
Techniques: photometric
Zdroj: Astronomy and Astrophysics-A&A
Astronomy and Astrophysics-A&A, EDP Sciences, 2016, 590, ⟨10.1051/0004-6361/201526378⟩
Astronomy and Astrophysics-A&A, 2016, 590, ⟨10.1051/0004-6361/201526378⟩
Astronomy & Astrophysics
ISSN: 0004-6361
DOI: 10.1051/0004-6361/201526378⟩
Popis: High redshift star-forming galaxies are discovered routinely through a flux excess in narrowband filters (NB) caused by an emission line. In most cases, the width of such filters is broad compared to typical line widths, and the throughput of the filters varies substantially within the bandpass. This leads to substantial uncertainties in redshifts and fluxes that are derived from the observations with one specific NB. In this work we demonstrate that the uncertainty in measured line parameters can be sharply reduced by using repeated observations of the same target field with filters that have slightly different transmittance curves. Such data are routinely collected with some large field imaging cameras that use multiple detectors and a separate filter for each of the detectors. An example is the NB118 data from ESO's VISTA InfraRed CAMera (VIRCAM). We carefully developed and characterized this method to determine more accurate redshift and line flux estimates from the ratio of apparent fluxes measured from observations in different narrowband filters and several matching broadband filters. Then, we tested the obtainable quality of parameter estimation both on simulated and actual observations for the example of Ha in the VIRCAM NB118 filters combined with broadband data in Y, J, H. We find that by using this method, the errors in the measured lines fluxes can be reduced up to almost an order of magnitude and that an accuracy in wavelength of better than 1nm can be achieved with the ~13nm wide NB118 filters.
25 pages, 24 figures; accepted for publication in A&A; arXiv abstract is shortened w.r.t. paper abstract
Databáze: OpenAIRE
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