The CALIFA view on stellar angular momentum across the Hubble sequence

¹ Instituto de Astrofísica de Canarias, Vía Láctea s/n, 38205 La Laguna, Tenerife, Spain
e-mail: jfalcon@iac.es
² Departamento de Astrofísica, Universidad de La Laguna, 38205 La Laguna, Tenerife, Spain
³ Department of Astrophysics, University of Vienna, Türkenschanzstrasse 17, 1180 Vienna, Austria
⁴ European Southern Observatory, Karl-Schwarzschild-Str. 2, 85748 Garching b. München, Germany
⁵ Leibniz-Institut für Astrophysik Potsdam (AIP), An der Sternwarte 16, 14482 Potsdam, Germany
⁶ Instituto de Astronomía, Universidad Nacional Autónoma de México, Apartado Postal 70-264, México D.F. 04510, Mexico
⁷ Max-Planck-Institut für Astronomie, Königstuhl 17, 69117 Heidelberg, Germany
⁸ Instituto de Astrofísica de Andalucía (IAA/CSIC), Glorieta de la Astronomía s/n Aptdo. 3004, 18080 Granada, Spain
⁹ Observatorio Astronómico, Laprida 854, X5000BGR Córdoba, Argentina
¹⁰ Consejo de Investigaciones Científicas y Técnicas de la República Argentina, Avda. Rivadavia 1917, C1033AAJ CABA, Argentina
¹¹ INAF-Osservatorio Astrofisico di Arcetri – Largo Enrico Fermi, 50125 Firenze, Italy
¹² Shanghai Astronomical Observatory, Chinese Academy of Sciences, 80 Nandan Road, Shanghai 200030, PR China
¹³ PITT PACC, Department of Physics and Astronomy, University of Pitts-burgh, Pittsburgh, PA 15260, USA
¹⁴ Departamento de Física Teórica, Universidad Autónoma de Madrid, 28049 Madrid, Spain
¹⁵ School of Physics and Astronomy, University of St Andrews, North Haugh, St Andrews KY16 9SS, UK
¹⁶ Sydney Institute for Astronomy, School of Physics A28, University of Sydney, Sydney, NSW 2006, Australia
¹⁷ ARC Centre of Excellence for All-sky Astrophysics in 3D (ASTRO-3D), Australia
¹⁸ Departamento de Física, Universidade Federal de Santa Catarina, PO Box 476, 88040-900 Florianópolis, SC, Brazil
¹⁹ ETH Zürich, Institute for Astronomy, Wolfgang-Pauli-Str. 27, 8093 Zürich, Switzerland
²⁰ Kapteyn Astronomical Institute, University of Groningen, Postbus 800, 9700 Groningen, The Netherlands
²¹ Departamento de Física Teórica y del Cosmos, University of Granada, Facultad de Ciencias (Edificio Mecenas), 18071 Granada, Spain
²² Instituto Carlos I de Física Teórica y Computación, Spain
²³ Instituto Nacional de Astrofísica, Óptica y Electrónica, Luis E. Erro 1, 72840 Tonantzintla, Puebla, Mexico

Received: 30 July 2019
Accepted: 11 October 2019

Abstract

We present the apparent stellar angular momentum over the optical extent of 300 galaxies across the Hubble sequence using integral-field spectroscopic (IFS) data from the CALIFA survey. Adopting the same λ_R parameter previously used to distinguish between slow and fast rotating early-type (elliptical and lenticular) galaxies, we show that spiral galaxies are almost all fast rotators, as expected. Given the extent of our data, we provide relations for λ_R measured in different apertures (e.g. fractions of the effective radius: 0.5 R_e, R_e, 2 R_e), including conversions to long-slit 1D apertures. Our sample displays a wide range of λ_Re values, consistent with previous IFS studies. The fastest rotators are dominated by relatively massive and highly star-forming Sb galaxies, which preferentially reside in the main star-forming sequence. These galaxies reach λ_Re values of ∼0.85, and they are the largest galaxies at a given mass, while also displaying some of the strongest stellar population gradients. Compared to the population of S0 galaxies, our findings suggest that fading may not be the dominant mechanism transforming spirals into lenticulars. Interestingly, we find that λ_Re decreases for late-type Sc and Sd spiral galaxies, with values that occasionally set them in the slow-rotator regime. While for some of them this can be explained by their irregular morphologies and/or face-on configurations, others are edge-on systems with no signs of significant dust obscuration. The latter are typically at the low-mass end, but this does not explain their location in the classical (V/σ, ε) and (λ_Re, ε) diagrams. Our initial investigations, based on dynamical models, suggest that these are dynamically hot disks, probably influenced by the observed important fraction of dark matter within R_e.