CALIFA, the calar alto legacy integral field area survey: I. survey presentation

S. F. Sánchez, R. C. Kennicutt, A. Gil De Paz, G. Van De Ven, J. M. Vílchez, L. Wisotzki, C. J. Walcher, D. Mast, J. A L Aguerri, S. Albiol-Pérez, A. Alonso-Herrero, J. Alves, J. Bakos, T. Bartáková, J. Bland-Hawthorn, A. Boselli, D. J. Bomans, A. Castillo-Morales, C. Cortijo-Ferrero, A. De Lorenzo-Cáceres & 52 others A. Del Olmo, R. J. Dettmar, A. Díaz, S. Ellis, J. Falcón-Barroso, H. Flores, A. Gallazzi, B. García-Lorenzo, R. González Delgado, N. Gruel, T. Haines, C. Hao, B. Husemann, J. Iglésias-Páramo, K. Jahnke, B. Johnson, B. Jungwiert, V. Kalinova, C. Kehrig, D. Kupko, A. R. López-Sánchez, M. Lyubenova, R. A. Marino, E. Mármol-Queraltó, I. Márquez, J. Masegosa, S. Meidt, J. Mendez-Abreu, A. Monreal-Ibero, C. Montijo, A. M. Mourão, G. Palacios-Navarro, P. Papaderos, A. Pasquali, R. Peletier, E. Pérez, I. Pérez, A. Quirrenbach, M. Relaño, F. F. Rosales-Ortega, M. M. Roth, T. Ruiz-Lara, P. Sánchez-Blázquez, C. Sengupta, R. Singh, V. Stanishev, S. C. Trager, A. Vazdekis, K. Viironen, V. Wild, S. Zibetti, B. Ziegler

Research output: Contribution to journalArticleResearchpeer-review

Abstract

The final product of galaxy evolution through cosmic time is the population of galaxies in the local universe. These galaxies are also those that can be studied in most detail, thus providing a stringent benchmark for our understanding of galaxy evolution. Through the huge success of spectroscopic single-fiber, statistical surveys of the Local Universe in the last decade, it has become clear, however, that an authoritative observational description of galaxies will involve measuring their spatially resolved properties over their full optical extent for a statistically significant sample. We present here the Calar Alto Legacy Integral Field Area (CALIFA) survey, which has been designed to provide a first step in this direction. We summarize the survey goals and design, including sample selection and observational strategy. We also showcase the data taken during the first observing runs (June/July 2010) and outline the reduction pipeline, quality control schemes and general characteristics of the reduced data. This survey is obtaining spatially resolved spectroscopic information of a diameter selected sample of ∼600 galaxies in the Local Universe (0.005 < z < 0.03). CALIFA has been designed to allow the building of two-dimensional maps of the following quantities: (a) stellar populations: ages and metallicities; (b) ionized gas: distribution, excitation mechanism and chemical abundances; and (c) kinematic properties: both from stellar and ionized gas components. CALIFA uses the PPAK integral field unit (IFU), with a hexagonal field-of-view of ∼1.3 ′, with a 100% covering factor by adopting a three-pointing dithering scheme. The optical wavelength range is covered from 3700 to 7000 Å, using two overlapping setups (V500 and V1200), with different resolutions: R ∼ 850 and R ∼ 1650, respectively. CALIFA is a legacy survey, intended for the community. The reduced data will be released, once the quality has been guaranteed. The analyzed data fulfillthe expectations of the original observing proposal, on the basis of a set of quality checks and exploratory analysis: (i) the final datacubes reach a 3σ limiting surface brightness depth of ∼23.0 mag/arcsec 2 for the V500 grating data (∼22.8 mag/arcsec 2 for V1200); (ii) about ∼70% of the covered field-of-view is above this 3σ limit; (iii) the data have a blue-to-red relative flux calibration within a few percent in most of the wavelength range; (iv) the absolute flux calibration is accurate within ∼8% with respect to SDSS; (v) the measured spectral resolution is ∼85 km s -1 for V1200 (∼150 km s -1 for V500); (vi) the estimated accuracy of the wavelength calibration is ∼5 km s -1 for the V1200 data (∼10 km s -1 for the V500 data); (vii) the aperture matched CALIFA and SDSS spectra are qualitatively and quantitatively similar. Finally, we show that we are able to carry out all measurements indicated above, recovering the properties of the stellar populations, the ionized gas andthe kinematics of both components. The associated maps illustrate the spatial variation of these parameters across the field, reemphasizing the redshift dependence of single aperture spectroscopic measurements. We conclude from this first look at the data that CALIFA will be an important resource for archaeological studies of galaxies in the Local Universe.

LanguageEnglish
Article numberA8
Pages1-31
Number of pages31
JournalAstronomy and Astrophysics
Volume538
DOIs
Publication statusPublished - 2012

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galaxies
ionized gases
universe
field of view
kinematics
calibration
wavelength
apertures
wavelengths
gas
quality control
spectral resolution
general characteristics
metallicity
proposals
resources
brightness
coverings
gratings
spatial variation

Cite this

Sánchez, S. F., Kennicutt, R. C., Gil De Paz, A., Van De Ven, G., Vílchez, J. M., Wisotzki, L., ... Ziegler, B. (2012). CALIFA, the calar alto legacy integral field area survey: I. survey presentation. Astronomy and Astrophysics, 538, 1-31. [A8]. https://doi.org/10.1051/0004-6361/201117353
Sánchez, S. F. ; Kennicutt, R. C. ; Gil De Paz, A. ; Van De Ven, G. ; Vílchez, J. M. ; Wisotzki, L. ; Walcher, C. J. ; Mast, D. ; Aguerri, J. A L ; Albiol-Pérez, S. ; Alonso-Herrero, A. ; Alves, J. ; Bakos, J. ; Bartáková, T. ; Bland-Hawthorn, J. ; Boselli, A. ; Bomans, D. J. ; Castillo-Morales, A. ; Cortijo-Ferrero, C. ; De Lorenzo-Cáceres, A. ; Del Olmo, A. ; Dettmar, R. J. ; Díaz, A. ; Ellis, S. ; Falcón-Barroso, J. ; Flores, H. ; Gallazzi, A. ; García-Lorenzo, B. ; González Delgado, R. ; Gruel, N. ; Haines, T. ; Hao, C. ; Husemann, B. ; Iglésias-Páramo, J. ; Jahnke, K. ; Johnson, B. ; Jungwiert, B. ; Kalinova, V. ; Kehrig, C. ; Kupko, D. ; López-Sánchez, A. R. ; Lyubenova, M. ; Marino, R. A. ; Mármol-Queraltó, E. ; Márquez, I. ; Masegosa, J. ; Meidt, S. ; Mendez-Abreu, J. ; Monreal-Ibero, A. ; Montijo, C. ; Mourão, A. M. ; Palacios-Navarro, G. ; Papaderos, P. ; Pasquali, A. ; Peletier, R. ; Pérez, E. ; Pérez, I. ; Quirrenbach, A. ; Relaño, M. ; Rosales-Ortega, F. F. ; Roth, M. M. ; Ruiz-Lara, T. ; Sánchez-Blázquez, P. ; Sengupta, C. ; Singh, R. ; Stanishev, V. ; Trager, S. C. ; Vazdekis, A. ; Viironen, K. ; Wild, V. ; Zibetti, S. ; Ziegler, B. / CALIFA, the calar alto legacy integral field area survey : I. survey presentation. In: Astronomy and Astrophysics. 2012 ; Vol. 538. pp. 1-31.
@article{89843261b8ac4541b9eab1c05130dbcf,
title = "CALIFA, the calar alto legacy integral field area survey: I. survey presentation",
abstract = "The final product of galaxy evolution through cosmic time is the population of galaxies in the local universe. These galaxies are also those that can be studied in most detail, thus providing a stringent benchmark for our understanding of galaxy evolution. Through the huge success of spectroscopic single-fiber, statistical surveys of the Local Universe in the last decade, it has become clear, however, that an authoritative observational description of galaxies will involve measuring their spatially resolved properties over their full optical extent for a statistically significant sample. We present here the Calar Alto Legacy Integral Field Area (CALIFA) survey, which has been designed to provide a first step in this direction. We summarize the survey goals and design, including sample selection and observational strategy. We also showcase the data taken during the first observing runs (June/July 2010) and outline the reduction pipeline, quality control schemes and general characteristics of the reduced data. This survey is obtaining spatially resolved spectroscopic information of a diameter selected sample of ∼600 galaxies in the Local Universe (0.005 < z < 0.03). CALIFA has been designed to allow the building of two-dimensional maps of the following quantities: (a) stellar populations: ages and metallicities; (b) ionized gas: distribution, excitation mechanism and chemical abundances; and (c) kinematic properties: both from stellar and ionized gas components. CALIFA uses the PPAK integral field unit (IFU), with a hexagonal field-of-view of ∼1.3 ′, with a 100{\%} covering factor by adopting a three-pointing dithering scheme. The optical wavelength range is covered from 3700 to 7000 {\AA}, using two overlapping setups (V500 and V1200), with different resolutions: R ∼ 850 and R ∼ 1650, respectively. CALIFA is a legacy survey, intended for the community. The reduced data will be released, once the quality has been guaranteed. The analyzed data fulfillthe expectations of the original observing proposal, on the basis of a set of quality checks and exploratory analysis: (i) the final datacubes reach a 3σ limiting surface brightness depth of ∼23.0 mag/arcsec 2 for the V500 grating data (∼22.8 mag/arcsec 2 for V1200); (ii) about ∼70{\%} of the covered field-of-view is above this 3σ limit; (iii) the data have a blue-to-red relative flux calibration within a few percent in most of the wavelength range; (iv) the absolute flux calibration is accurate within ∼8{\%} with respect to SDSS; (v) the measured spectral resolution is ∼85 km s -1 for V1200 (∼150 km s -1 for V500); (vi) the estimated accuracy of the wavelength calibration is ∼5 km s -1 for the V1200 data (∼10 km s -1 for the V500 data); (vii) the aperture matched CALIFA and SDSS spectra are qualitatively and quantitatively similar. Finally, we show that we are able to carry out all measurements indicated above, recovering the properties of the stellar populations, the ionized gas andthe kinematics of both components. The associated maps illustrate the spatial variation of these parameters across the field, reemphasizing the redshift dependence of single aperture spectroscopic measurements. We conclude from this first look at the data that CALIFA will be an important resource for archaeological studies of galaxies in the Local Universe.",
author = "S{\'a}nchez, {S. F.} and Kennicutt, {R. C.} and {Gil De Paz}, A. and {Van De Ven}, G. and V{\'i}lchez, {J. M.} and L. Wisotzki and Walcher, {C. J.} and D. Mast and Aguerri, {J. A L} and S. Albiol-P{\'e}rez and A. Alonso-Herrero and J. Alves and J. Bakos and T. Bart{\'a}kov{\'a} and J. Bland-Hawthorn and A. Boselli and Bomans, {D. J.} and A. Castillo-Morales and C. Cortijo-Ferrero and {De Lorenzo-C{\'a}ceres}, A. and {Del Olmo}, A. and Dettmar, {R. J.} and A. D{\'i}az and S. Ellis and J. Falc{\'o}n-Barroso and H. Flores and A. Gallazzi and B. Garc{\'i}a-Lorenzo and {Gonz{\'a}lez Delgado}, R. and N. Gruel and T. Haines and C. Hao and B. Husemann and J. Igl{\'e}sias-P{\'a}ramo and K. Jahnke and B. Johnson and B. Jungwiert and V. Kalinova and C. Kehrig and D. Kupko and L{\'o}pez-S{\'a}nchez, {A. R.} and M. Lyubenova and Marino, {R. A.} and E. M{\'a}rmol-Queralt{\'o} and I. M{\'a}rquez and J. Masegosa and S. Meidt and J. Mendez-Abreu and A. Monreal-Ibero and C. Montijo and Mour{\~a}o, {A. M.} and G. Palacios-Navarro and P. Papaderos and A. Pasquali and R. Peletier and E. P{\'e}rez and I. P{\'e}rez and A. Quirrenbach and M. Rela{\~n}o and Rosales-Ortega, {F. F.} and Roth, {M. M.} and T. Ruiz-Lara and P. S{\'a}nchez-Bl{\'a}zquez and C. Sengupta and R. Singh and V. Stanishev and Trager, {S. C.} and A. Vazdekis and K. Viironen and V. Wild and S. Zibetti and B. Ziegler",
year = "2012",
doi = "10.1051/0004-6361/201117353",
language = "English",
volume = "538",
pages = "1--31",
journal = "Astronomy and Astrophysics",
issn = "0004-6361",
publisher = "EDP Sciences",

}

Sánchez, SF, Kennicutt, RC, Gil De Paz, A, Van De Ven, G, Vílchez, JM, Wisotzki, L, Walcher, CJ, Mast, D, Aguerri, JAL, Albiol-Pérez, S, Alonso-Herrero, A, Alves, J, Bakos, J, Bartáková, T, Bland-Hawthorn, J, Boselli, A, Bomans, DJ, Castillo-Morales, A, Cortijo-Ferrero, C, De Lorenzo-Cáceres, A, Del Olmo, A, Dettmar, RJ, Díaz, A, Ellis, S, Falcón-Barroso, J, Flores, H, Gallazzi, A, García-Lorenzo, B, González Delgado, R, Gruel, N, Haines, T, Hao, C, Husemann, B, Iglésias-Páramo, J, Jahnke, K, Johnson, B, Jungwiert, B, Kalinova, V, Kehrig, C, Kupko, D, López-Sánchez, AR, Lyubenova, M, Marino, RA, Mármol-Queraltó, E, Márquez, I, Masegosa, J, Meidt, S, Mendez-Abreu, J, Monreal-Ibero, A, Montijo, C, Mourão, AM, Palacios-Navarro, G, Papaderos, P, Pasquali, A, Peletier, R, Pérez, E, Pérez, I, Quirrenbach, A, Relaño, M, Rosales-Ortega, FF, Roth, MM, Ruiz-Lara, T, Sánchez-Blázquez, P, Sengupta, C, Singh, R, Stanishev, V, Trager, SC, Vazdekis, A, Viironen, K, Wild, V, Zibetti, S & Ziegler, B 2012, 'CALIFA, the calar alto legacy integral field area survey: I. survey presentation', Astronomy and Astrophysics, vol. 538, A8, pp. 1-31. https://doi.org/10.1051/0004-6361/201117353

CALIFA, the calar alto legacy integral field area survey : I. survey presentation. / Sánchez, S. F.; Kennicutt, R. C.; Gil De Paz, A.; Van De Ven, G.; Vílchez, J. M.; Wisotzki, L.; Walcher, C. J.; Mast, D.; Aguerri, J. A L; Albiol-Pérez, S.; Alonso-Herrero, A.; Alves, J.; Bakos, J.; Bartáková, T.; Bland-Hawthorn, J.; Boselli, A.; Bomans, D. J.; Castillo-Morales, A.; Cortijo-Ferrero, C.; De Lorenzo-Cáceres, A.; Del Olmo, A.; Dettmar, R. J.; Díaz, A.; Ellis, S.; Falcón-Barroso, J.; Flores, H.; Gallazzi, A.; García-Lorenzo, B.; González Delgado, R.; Gruel, N.; Haines, T.; Hao, C.; Husemann, B.; Iglésias-Páramo, J.; Jahnke, K.; Johnson, B.; Jungwiert, B.; Kalinova, V.; Kehrig, C.; Kupko, D.; López-Sánchez, A. R.; Lyubenova, M.; Marino, R. A.; Mármol-Queraltó, E.; Márquez, I.; Masegosa, J.; Meidt, S.; Mendez-Abreu, J.; Monreal-Ibero, A.; Montijo, C.; Mourão, A. M.; Palacios-Navarro, G.; Papaderos, P.; Pasquali, A.; Peletier, R.; Pérez, E.; Pérez, I.; Quirrenbach, A.; Relaño, M.; Rosales-Ortega, F. F.; Roth, M. M.; Ruiz-Lara, T.; Sánchez-Blázquez, P.; Sengupta, C.; Singh, R.; Stanishev, V.; Trager, S. C.; Vazdekis, A.; Viironen, K.; Wild, V.; Zibetti, S.; Ziegler, B.

In: Astronomy and Astrophysics, Vol. 538, A8, 2012, p. 1-31.

Research output: Contribution to journalArticleResearchpeer-review

TY - JOUR

T1 - CALIFA, the calar alto legacy integral field area survey

T2 - Astronomy and Astrophysics

AU - Sánchez, S. F.

AU - Kennicutt, R. C.

AU - Gil De Paz, A.

AU - Van De Ven, G.

AU - Vílchez, J. M.

AU - Wisotzki, L.

AU - Walcher, C. J.

AU - Mast, D.

AU - Aguerri, J. A L

AU - Albiol-Pérez, S.

AU - Alonso-Herrero, A.

AU - Alves, J.

AU - Bakos, J.

AU - Bartáková, T.

AU - Bland-Hawthorn, J.

AU - Boselli, A.

AU - Bomans, D. J.

AU - Castillo-Morales, A.

AU - Cortijo-Ferrero, C.

AU - De Lorenzo-Cáceres, A.

AU - Del Olmo, A.

AU - Dettmar, R. J.

AU - Díaz, A.

AU - Ellis, S.

AU - Falcón-Barroso, J.

AU - Flores, H.

AU - Gallazzi, A.

AU - García-Lorenzo, B.

AU - González Delgado, R.

AU - Gruel, N.

AU - Haines, T.

AU - Hao, C.

AU - Husemann, B.

AU - Iglésias-Páramo, J.

AU - Jahnke, K.

AU - Johnson, B.

AU - Jungwiert, B.

AU - Kalinova, V.

AU - Kehrig, C.

AU - Kupko, D.

AU - López-Sánchez, A. R.

AU - Lyubenova, M.

AU - Marino, R. A.

AU - Mármol-Queraltó, E.

AU - Márquez, I.

AU - Masegosa, J.

AU - Meidt, S.

AU - Mendez-Abreu, J.

AU - Monreal-Ibero, A.

AU - Montijo, C.

AU - Mourão, A. M.

AU - Palacios-Navarro, G.

AU - Papaderos, P.

AU - Pasquali, A.

AU - Peletier, R.

AU - Pérez, E.

AU - Pérez, I.

AU - Quirrenbach, A.

AU - Relaño, M.

AU - Rosales-Ortega, F. F.

AU - Roth, M. M.

AU - Ruiz-Lara, T.

AU - Sánchez-Blázquez, P.

AU - Sengupta, C.

AU - Singh, R.

AU - Stanishev, V.

AU - Trager, S. C.

AU - Vazdekis, A.

AU - Viironen, K.

AU - Wild, V.

AU - Zibetti, S.

AU - Ziegler, B.

PY - 2012

Y1 - 2012

N2 - The final product of galaxy evolution through cosmic time is the population of galaxies in the local universe. These galaxies are also those that can be studied in most detail, thus providing a stringent benchmark for our understanding of galaxy evolution. Through the huge success of spectroscopic single-fiber, statistical surveys of the Local Universe in the last decade, it has become clear, however, that an authoritative observational description of galaxies will involve measuring their spatially resolved properties over their full optical extent for a statistically significant sample. We present here the Calar Alto Legacy Integral Field Area (CALIFA) survey, which has been designed to provide a first step in this direction. We summarize the survey goals and design, including sample selection and observational strategy. We also showcase the data taken during the first observing runs (June/July 2010) and outline the reduction pipeline, quality control schemes and general characteristics of the reduced data. This survey is obtaining spatially resolved spectroscopic information of a diameter selected sample of ∼600 galaxies in the Local Universe (0.005 < z < 0.03). CALIFA has been designed to allow the building of two-dimensional maps of the following quantities: (a) stellar populations: ages and metallicities; (b) ionized gas: distribution, excitation mechanism and chemical abundances; and (c) kinematic properties: both from stellar and ionized gas components. CALIFA uses the PPAK integral field unit (IFU), with a hexagonal field-of-view of ∼1.3 ′, with a 100% covering factor by adopting a three-pointing dithering scheme. The optical wavelength range is covered from 3700 to 7000 Å, using two overlapping setups (V500 and V1200), with different resolutions: R ∼ 850 and R ∼ 1650, respectively. CALIFA is a legacy survey, intended for the community. The reduced data will be released, once the quality has been guaranteed. The analyzed data fulfillthe expectations of the original observing proposal, on the basis of a set of quality checks and exploratory analysis: (i) the final datacubes reach a 3σ limiting surface brightness depth of ∼23.0 mag/arcsec 2 for the V500 grating data (∼22.8 mag/arcsec 2 for V1200); (ii) about ∼70% of the covered field-of-view is above this 3σ limit; (iii) the data have a blue-to-red relative flux calibration within a few percent in most of the wavelength range; (iv) the absolute flux calibration is accurate within ∼8% with respect to SDSS; (v) the measured spectral resolution is ∼85 km s -1 for V1200 (∼150 km s -1 for V500); (vi) the estimated accuracy of the wavelength calibration is ∼5 km s -1 for the V1200 data (∼10 km s -1 for the V500 data); (vii) the aperture matched CALIFA and SDSS spectra are qualitatively and quantitatively similar. Finally, we show that we are able to carry out all measurements indicated above, recovering the properties of the stellar populations, the ionized gas andthe kinematics of both components. The associated maps illustrate the spatial variation of these parameters across the field, reemphasizing the redshift dependence of single aperture spectroscopic measurements. We conclude from this first look at the data that CALIFA will be an important resource for archaeological studies of galaxies in the Local Universe.

AB - The final product of galaxy evolution through cosmic time is the population of galaxies in the local universe. These galaxies are also those that can be studied in most detail, thus providing a stringent benchmark for our understanding of galaxy evolution. Through the huge success of spectroscopic single-fiber, statistical surveys of the Local Universe in the last decade, it has become clear, however, that an authoritative observational description of galaxies will involve measuring their spatially resolved properties over their full optical extent for a statistically significant sample. We present here the Calar Alto Legacy Integral Field Area (CALIFA) survey, which has been designed to provide a first step in this direction. We summarize the survey goals and design, including sample selection and observational strategy. We also showcase the data taken during the first observing runs (June/July 2010) and outline the reduction pipeline, quality control schemes and general characteristics of the reduced data. This survey is obtaining spatially resolved spectroscopic information of a diameter selected sample of ∼600 galaxies in the Local Universe (0.005 < z < 0.03). CALIFA has been designed to allow the building of two-dimensional maps of the following quantities: (a) stellar populations: ages and metallicities; (b) ionized gas: distribution, excitation mechanism and chemical abundances; and (c) kinematic properties: both from stellar and ionized gas components. CALIFA uses the PPAK integral field unit (IFU), with a hexagonal field-of-view of ∼1.3 ′, with a 100% covering factor by adopting a three-pointing dithering scheme. The optical wavelength range is covered from 3700 to 7000 Å, using two overlapping setups (V500 and V1200), with different resolutions: R ∼ 850 and R ∼ 1650, respectively. CALIFA is a legacy survey, intended for the community. The reduced data will be released, once the quality has been guaranteed. The analyzed data fulfillthe expectations of the original observing proposal, on the basis of a set of quality checks and exploratory analysis: (i) the final datacubes reach a 3σ limiting surface brightness depth of ∼23.0 mag/arcsec 2 for the V500 grating data (∼22.8 mag/arcsec 2 for V1200); (ii) about ∼70% of the covered field-of-view is above this 3σ limit; (iii) the data have a blue-to-red relative flux calibration within a few percent in most of the wavelength range; (iv) the absolute flux calibration is accurate within ∼8% with respect to SDSS; (v) the measured spectral resolution is ∼85 km s -1 for V1200 (∼150 km s -1 for V500); (vi) the estimated accuracy of the wavelength calibration is ∼5 km s -1 for the V1200 data (∼10 km s -1 for the V500 data); (vii) the aperture matched CALIFA and SDSS spectra are qualitatively and quantitatively similar. Finally, we show that we are able to carry out all measurements indicated above, recovering the properties of the stellar populations, the ionized gas andthe kinematics of both components. The associated maps illustrate the spatial variation of these parameters across the field, reemphasizing the redshift dependence of single aperture spectroscopic measurements. We conclude from this first look at the data that CALIFA will be an important resource for archaeological studies of galaxies in the Local Universe.

UR - http://www.scopus.com/inward/record.url?scp=84858324163&partnerID=8YFLogxK

U2 - 10.1051/0004-6361/201117353

DO - 10.1051/0004-6361/201117353

M3 - Article

VL - 538

SP - 1

EP - 31

JO - Astronomy and Astrophysics

JF - Astronomy and Astrophysics

SN - 0004-6361

M1 - A8

ER -

Sánchez SF, Kennicutt RC, Gil De Paz A, Van De Ven G, Vílchez JM, Wisotzki L et al. CALIFA, the calar alto legacy integral field area survey: I. survey presentation. Astronomy and Astrophysics. 2012;538:1-31. A8. https://doi.org/10.1051/0004-6361/201117353