How Barred is the NIR Nearby Universe? An analysis using 2MASS

We determine a firm lower limit to the bar fraction of 0.58 in the nearby universe using J+H+Ks-band images for 134 spirals from 2MASS. With a mean deprojected semi-major axis of 5.1 kpc, and a mean deprojected ellipticity of 0.45 this local bar sample lays the ground work for studies on bar formation and evolution at high redshift.Comment: In the proceedings "Penetrating Bars through Masks of Cosmic Dust: The Hubble Tuning Fork strikes a New Note

Bar fraction in lenticular galaxies: dependence on luminosity and environment

We present a study of bars in lenticular galaxies based on a sample of 371 galaxies from the SDSS-DR 7 and 2MASS in optical and near-infrared bands, respectively. We found a bar in 15% of the lenticular galaxies in our sample, which is consistent with recent studies. The barred galaxy fraction shows a luminosity dependence, with faint lenticular galaxies (MK > -24.5, total absolute magnitude in K band) having a larger fraction of bars than bright lenticular galaxies (MK < -24.5). A similar trend is seen when Mr = -21.5, the total absolute magnitude in SDSS r band is used to divide the sample into faint and bright lenticular galaxies. We find that faint galaxies in clusters show a higher bar fraction than their counterparts in the field. This suggests that the formation of bars in lenticular galaxies not only depends on the total luminosity of galaxy but also on the environment of the host galaxy.Comment: Accepted for publication in MNRAS: Letters, 5 pages, 4 figure

Extreme Starbursts in the Local Universe

The "Extreme starbursts in the local universe" workshop was held at the Insituto de Astrofisica de Andalucia in Granada, Spain on 21-25 June 2010. Bearing in mind the advent of a new generation of facilities such as JWST, Herschel, ALMA, eVLA and eMerlin, the aim of the workshop was to bring together observers and theorists to review the latest results. The purpose of the workshop was to address the following issues: what are the main modes of triggering extreme starbursts in the local Universe? How efficiently are stars formed in extreme starbursts? What are the star formation histories of local starburst galaxies? How well do the theoretical simulations model the observations? What can we learn about starbursts in the distant Universe through studies of their local counterparts? How important is the role of extreme starbursts in the hierarchical assembly of galaxies? How are extreme starbursts related to the triggering of AGN in the nuclei of galaxies? Overall, 41 talks and 4 posters with their corresponding 10 minutes short talks were presented during the workshop. In addition, the workshop was designed with emphasis on discussions, and therefore, there were 6 discussion sessions of up to one hour during the workshop. Here is presented a summary of the purposes of the workshop as well as a compilation of the abstracts corresponding to each of the presentations. The summary and conclusions of the workshop along with a description of the future prospects by Sylvain Veilleux can be found in the last section of this document. A photo of the assistants is included.Comment: worksho

HI and CO observations of Arp 104: a spiral-elliptical interacting pair

We present data probing the spatial and kinematical distribution of both the atomic (HI) and molecular (CO) gas in NGC 5218, the late-type barred spiral galaxy in the spiral-elliptical interacting pair, Arp 104. We consider these data in conjunction with far-infrared and radio continuum data, and N-body simulations, to study the galaxies interactions, and the star formation properties of NGC 5218. We use these data to assess the importance of the bar and tidal interaction on the evolution of NGC 5218, and the extent to which the tidal interaction may have been important in triggering the bar. The molecular gas distribution of NGC 5218 appears to have been strongly affected by the bar; the distribution is centrally condensed with a very large surface density in the central region. The N-body simulations indicate a timescale since perigalacticon of approximately 3 x 10**8 yr, which is consistent with the interaction having triggered or enhanced the bar potential in NGC 5218, leading to inflow and the large central molecular gas density observed. Whilst NGC 5218 appears to be undergoing active star formation, its star formation efficiency is comparable to a `normal' SBb galaxy. We propose that this system may be on the brink of a more active phase of star formation.Comment: 15 pages, accepted by MNRA

Mid-infrared spectroscopy of high-redshift submillimeter galaxies:First results

We present mid-infrared spectra of five submillimeter galaxies at z = 0.65-2.38 taken with the Spitzer Space Telescope. Four of these sources, at z ≾ 1.5, have strong PAH features and their composite spectrum is well fitted by an M82-like spectrum with an additional power-law component consistent with that expected from AGN activity. Based on comparison with local templates of the 7.7 μm PAH equivalent width and the PAH-to-infrared luminosity ratio, we conclude that these galaxies host both star formation and AGN activity, with star formation dominating the bolometric luminosity. The source at z = 2.38 displays a Mrk 231-type broad emission feature at rest frame ~8 μm that does not conform to the typical 7.7 μm/8.6 μm PAH complex in starburst galaxies, suggesting a more substantial AGN contribution