R. Cid Fernandes

Abstract: Context. The bar pattern speed (Ω_b) is defined as the rotational frequency of the bar, and it determines the bar dynamics. Several methods have been proposed for measuring Ω_b. The non-parametric method proposed by Tremaine & Weinberg (1984, ApJ, 282, L5; TW) and based on stellar kinematics is the most accurate. This method has been applied so far to 17 galaxies, most of them SB0 and SBa types. Aims. We have applied the TW method to a new sample of 15 strong and bright barred galaxies, spanning a wide range of morphological types from SB0 to SBbc. Combining our analysis with previous studies, we investigate 32 barred galaxies with their pattern speed measured by the TW method. The resulting total sample of barred galaxies allows us to study the dependence of Ω_b on galaxy properties, such as the Hubble type. Methods. We measured Ω_b using the TW method on the stellar velocity maps provided by the integral-field spectroscopy data from the CALIFA survey. Integral-field data solve the problems that long-slit data present when applying the TW method, resulting in the determination of more accurate Ω_b. In addition, we have also derived the ratio R of the corotation radius to the bar length of the galaxies. According to this parameter, bars can be classified as fast (R 1.4). Results. For all the galaxies, R is compatible within the errors with fast bars. We cannot rule out (at 95% level) the fast bar solution for any galaxy. We have not observed any significant trend between R and the galaxy morphological type. Conclusions. Our results indicate that independent of the Hubble type, bars have been formed and then evolve as fast rotators. This observational result will constrain the scenarios of formation and evolution of bars proposed by numerical simulations.

TL;DR: In this article, the authors argue that a large fraction of the systems in the right wing of galaxies could actually be galaxies which stopped forming stars and that the ionization in these "retired" galaxies would be produced by hot post-AGB stars and white dwarfs.

TL;DR: De Oliveira et al. as discussed by the authors, C. Mendes, C. de Oliveira, and C. Pereira, 2013. Universidade do Sao Paulo. Instituto de Astronomia, Geofisica e Ciencias Atmosfericas; Brasil

TL;DR: In this paper, a spectroscopic atlas of active galactic nuclei covering the region around the λλ8498, 8542, 8662 Calcium triplet (CaT) is presented.

TL;DR: In this article, the authors present the first results obtained with observations of the central regions of 57 LLAGNs imaged with the WFPC2 through any of the V (F555W, F547M, F614W) and I (F791W and F814W) filters that are available in the HST archive.