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

F.F.R.O. acknowledges financial support from the Mexican National Council for Science and Technology (CONACYT) under the programme Estancias Posdoctorales y Sabáticas al Extranjero para la Consolidación de Grupos de Investigación, 2010-2012. I.M. acknowledges financial support from the Spanish MINECO grant AYA 2010-15169, and from Junta de Andalucía TIC114 and Proyecto de Excelencia P08-TIC-03531; J.F.-B. from the Ramón y Cajal Program, grants AYA2010-21322-C03-02 and AIB-2010-DE-00227 from the Spanish Ministry of Economy and Competitiveness (MINECO), as well as from the FP7 Marie Curie Actions of the European Commission, via the Initial Training Network DAGAL under REA grant agreement na¸289313. C.J.W. acknowledges support through the Marie Curie Career Integration Grant 303912. E.M.Q. and J.F.-B. acknowledge support from the Spanish Programa Nacional de Astronomía y Astrofísica under grant AYA2010-21322-C03-02. This work has been partially funded by the Spanish PNAYA, project AYA2010-21887 of the Spanish MINECO. R.A. Marino was also funded by the Spanish Programme of International Campus of Excellence Moncloa (CEI).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 above0.7, 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 SAMIand 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 ina galaxy study: the number and distribution of H ii regions (Hαflux structure), the gas metallicity (using the O3N2 method), the gas ionization properties (through the [N II]/Hα and [O III]/Hβline 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.Publisher PDFPeer reviewe