We investigate the internal structure and density profiles of haloes of mass 1010-1014 M⊙ in the Evolution and Assembly of Galaxies and their Environment (EAGLE) simulations. These follow the formation of galaxies in a Λ cold dark matter Universe and include a treatment of the baryon physics thought to be relevant. The EAGLE simulations reproduce

We present measurements of internal proper motions at more than five hundred positions of the Eskimo Nebula (NGC 2392), based on images acquired at two epochs with WFPC2 on board the Hubble Space Telescope (the two epochs are separated by 7.695 yr). A detailed comparison of the two observations clearly shows the expansion of the nebula. We measured

We present an analysis of six spatially resolved planetary nebulae (PNe), NGC 3242, NGC 5315, NGC5882, NGC 7662, IC 2165, and IC 3568, from observations in the Cycle 19 program GO 12600 using HSTSTIS. These six observations cover the wavelength range 1150-10,270 Å with 0.2 and 0.5 arcsec wideslits, and are co-spatial to 0.1 arcsec along a 25 arcsec

Three of the best determinations of the primordial helium abundance (Yp) are those obtained from low metallicity HII regions by Aver, Olive, Porter, & Skillman (2013); Izotov, Thuan, & Guseva (2014); and Peimbert, Peimbert, & Luridiana (2007). In this poster we update the Yp determination by Peimbert et al. taking into account, among other aspects

Some of the world's largest telescopes and largest concentrations of telescopes are on sites in Arizona and the Canary Islands. Active site protection efforts are underway in both regions; the common challenge is getting out ahead of the LED revolution in outdoor lighting. We review the work with local, regional, and national government bodies

We report on our ongoing project "Statistical studies of HII regions in the nearby extra-galaxies". In this report we present the overview of our detailed study of warm dust in the nearby Galaxy NGC 4321 (M100). We measure the flux values in the 4 Spitzer-IRAC bands of some 275 HII regions in M100. In addition, we also present our new measurements