The effects of spatial resolution on integral field spectrograph surveys at different redshifts − The CALIFA perspective

¹ Centro Astronómico Hispano-Alemán, Calar Alto, (CSIC-MPG), C/Jesús Durbán Remón 2-2, 04004 Almería, Spain
e-mail: dmast@caha.es
² Instituto de Astrofísica de Andalucía (CSIC), Glorieta de la Astronomía s/n, 18008 Granada, Spain
³ Instituto Nacional de Astrofísica, Óptica y Electrónica, Luis E. Erro 1, 72840 Tonantzintla, Puebla, Mexico
⁴ Departamento de Física Teórica, Universidad Autónoma de Madrid, 28049 Madrid, Spain
⁵ Leibniz Institute for Astrophysics Potsdam, an der Sternwarte 16, 14482 Potsdam, Germany
⁶ CEI Campus Moncloa, UCM-UPM, Departamento de Astrofísica y CC. de la Atmósfera, Facultad de CC. Físicas, Universidad Complutense de Madrid, Avda. Complutense s/n, 28040 Madrid, Spain
⁷ Institute of Astronomy, University of Cambridge, Madingley Road, Cambridge CB3 0HA, UK
⁸ CENTRA Centro Multidisciplinar de Astrofísica, Instituto Superior Técnico, Av. Rovisco Pais 1, 1049-001 Lisbon, Portugal
⁹ School of Physics and Astronomy, University of St Andrews, North Haugh, St Andrews KY16 9SS, UK
¹⁰ Instituto de Astrofísica de Canarias (IAC), Glorieta de la Astronomía S/N, 38206 La Laguna, S/C de Tenerife, Spain
¹¹ Depto. Astrofísica, Universidad de La Laguna (ULL), 38206 La Laguna, Tenerife, Spain
¹² Dep. Física Teórica y del Cosmos, Campus de Fuentenueva, Universidad de Granada, 18071 Granada, Spain
¹³ Centro de Astrofísica and Faculdade de Ciências, Universidade do Porto, rua das Estrelas, 4150-762 Porto, Portugal
¹⁴ Astronomisches Institut, Ruhr-Universität Bochum, Universitätsstr. 150, 44801 Bochum, Germany
¹⁵ RUB Research Department Plasmas with Complex Interactions, 44801 Bochum, Germany
¹⁶ University of Vienna, Türkenschanzstrasse 17, 1180 Vienna, Austria
¹⁷ Sydney Institute for Astronomy, School of Physics A28, University of Sydney, Sydney 2006 NSW, Australia
¹⁸ Australian Astronomical Observatory, PO Box 915, North Ryde NSW 1670, Australia
¹⁹ 30 Department of Physics and Astronomy, Macquarie University, North Ryde NSW 2109, Australia
²⁰ Max Planck Institute for Astronomy, Königstuhl 17, 69117 Heidelberg, Germany

Received: 29 April 2013
Accepted: 15 November 2013

Abstract

Context. Over the past decade, 3D optical spectroscopy has become the preferred tool for understanding the properties of galaxies and is now increasingly used to carry out galaxy surveys. Low redshift surveys include SAURON, DiskMass, ATLAS3D, PINGS, and VENGA. At redshifts above 0.7, surveys such as MASSIV, SINS, GLACE, and IMAGES have targeted the most luminous galaxies to study mainly their kinematic properties. The on-going CALIFA survey (z ~ 0.02) is the first of a series of upcoming integral field spectroscopy (IFS) surveys with large samples representative of the entire population of galaxies. Others include SAMI and MaNGA at lower redshift and the upcoming KMOS surveys at higher redshift. Given the importance of spatial scales in IFS surveys, the study of the effects of spatial resolution on the recovered parameters becomes important.

Aims. We explore the capability of the CALIFA survey and a hypothetical higher redshift survey to reproduce the properties of a sample of objects observed with better spatial resolution at lower redshift.

Methods. Using a sample of PINGS galaxies, we simulated observations at different redshifts. We then studied the behaviour of different parameters as the spatial resolution degrades with increasing redshift.

Results. We show that at the CALIFA resolution, we are able to measure and map common observables in a galaxy study: the number and distribution of H ii regions (Hα  flux structure), the gas metallicity (using the O3N2 method), the gas ionization properties (through the [N ii]/Hα  and [O iii]/Hβ  line ratios), and the age of the underlying stellar population (using the D₄₀₀₀ index). This supports the aim of the survey to characterise the observable properties of galaxies in the Local Universe. Our analysis of simulated IFS data cubes at higher redshifts highlights the importance of the projected spatial scale per spaxel as the most important figure of merit in the design of an integral field survey.