On the accretion of a new group of galaxies on to Virgo: I. Internal kinematics of nine in-falling dEs

ABSTRACT Galaxy environment has been shown to play an important role in transforming late-type, star-forming galaxies to quiescent spheroids. This transformation is expected to be more severe for low-mass galaxies ($M \lt 10^{10}\, \mathrm{M}_\odot$) in dense galaxy groups and clusters, mostly due to the influence of their past host haloes (also known as pre-processing) and their present-day environments. For the first time, in this study, we investigate a sample of nine early-type dwarf galaxies (dEs) that were accreted as a likely bound group on to the Virgo galaxy cluster about 2–3 Gyr ago. Considering this special condition, these nine dEs may provide a test bed for distinguishing between the influence of the Virgo galaxy cluster and the effects of the previous host halo on their current properties. Specifically, we use VLT/MUSE integral-field unit spectra to derive their kinematics and specific angular momentum (λR) profiles. We observe a spread in the λR profiles of our sample dEs, finding that the λR profiles of half of them are as high as those of low-mass field galaxies. The remaining dEs exhibit λR profiles as low as those of Virgo dEs that were likely accreted longer ago. Moreover, we detect nebular emission in one dE with a gas velocity offset suggesting ongoing gas stripping in Virgo. We suggest that the low-λR dEs in our sample were processed by their previous host halo, prior to their infall to Virgo, and that the high-λR dEs may be experiencing ram pressure stripping in Virgo.

MASCARA-3b

We report the discovery of MASCARA-3b, a hot Jupiter orbiting its bright (V = 8.33) late F-type host every 5.55149 ± 0.00001 days in an almost circular orbit (e = 0.050−0.017+0.020). This is the fourth exoplanet discovered with the Multi-site All-Sky CAmeRA (MASCARA), and the first of these that orbits a late-type star. Follow-up spectroscopic measurements were obtained in and out of transit with the Hertzsprung SONG telescope. Combining the MASCARA photometry and SONG radial velocities reveals a radius and mass of 1.36 ± 0.05 RJup and 4.2 ± 0.2 MJup. In addition, SONG spectroscopic transit observations were obtained on two separate nights. From analyzing the mean out-of-transit broadening function, we obtain v sin i⋆ = 20.4 ± 0.4 km s−1. In addition, investigating the Rossiter-McLaughlin effect, as observed in the distortion of the stellar lines directly and through velocity anomalies, we find the projected obliquity to be λ = 1.2−7.4+8.2 deg, which is consistent with alignment.

UV-IR color profiles of the outer regions of 2K nearby S4G galaxies

We present our new, spatially-resolved, photometry in FUV and NUV from images obtained by GALEX, and IRAC1 (3.6 μm) photometry obtained by the Spitzer Space Telescope. We analyzed the surface brightness profiles μFUV, μNUV, μ[3.6], as well as the radial evolution of the (FUV-NUV), (FUV - [3.6]), and (NUV - [3.6]) colors in the Spitzer Survey of Stellar Structures in Galaxies (S4G) galaxies (d < 40 Mpc) sample. We defined the GALEX Blue Sequence (GBS) and GALEX Red Sequence (GBR) from the (FUV - NUV) versus (NUV - [3.6]) color-color diagram, populated by late-type star forming galaxies and quiescent early-type galaxies respectively. While most disk becomes radially bluer for GBS galaxies, and stay constant for GRS galaxies, a large fraction ( > 50%) of intermediary GALEX Green Valley (GGV) galaxies’ outer disks are becoming redder. An outside-in quenching mechanism such as environmentally-related mechanisms such as starvation or ram-pressure-stripping could explain our results.

Towards Extraction of Massive DIB Datasets from Stellar Spectroscopic Surveys

Medium to high-resolution stellar spectroscopic surveys can potentially be used to build DIB databases by means of automated methods of analysis. Multiplex spectrographs increase strongly those potentialities and allow small-scale variability studies. Because measurements of the stellar parameters are generally the primary goal of the surveys, synthetic spectra can be computed and used to extract DIBs from late-type star data. Large datasets should allow deeper investigations on the DIB variability in response to stellar radiation fields, DIB reddening relationships, and help localizing interstellar clouds. Here we describe our attempts to build and test automated methods adapted to both early and late type stars.

An Astrobiological Experiment to Explore the Habitability of Tidally Locked M-Dwarf Planets

We present a summary of a three-year academic research proposal drafted during the Sao Paulo Advanced School of Astrobiology (SPASA) to prepare for upcoming observations of tidally locked planets orbiting M-dwarf stars. The primary experimental goal of the suggested research is to expose extremophiles from analogue environments to a modified space simulation chamber reproducing the environmental parameters of a tidally locked planet in the habitable zone of a late-type star. Here we focus on a description of the astronomical analysis used to define the parameters for this climate simulation.