A detailed analysis of how environment affects the star formation history of early-type galaxies (ETGs) is undertaken via high signal-to-noise ratio stacked spectra obtained from a sample of 20 977 ETGs (morphologically selected) from the Sloan Digital Sky Survey-based SPIDER survey. Two major parameters are considered for the study: the central

NGC4321 is a two-armed grand design spiral galaxy in the Virgo Cluster. HI emission line data with 15 arcsecond resolution from the VLA map the velocity field of the hydrogen gas in the disk of NGC4321. In a grand design spiral galaxy, the presence of a spiral density wave causes deviations from circular rotation in the gas. The observed velocity

We present 5-40 μm spectroscopy of 41 planetary nebulae (PNe) in the Magellanic Clouds, observed with the Infrared Spectrograph on board the Spitzer Space Telescope. The spectra show the presence of a combination of nebular emission lines and solid state features from dust, superimposed on the thermal IR continuum. By analyzing the 25 LMC and 16

We present results on low-resolution mid-infrared spectroscopy of a sample of 70 infrared-luminous galaxies and quasars obtained with the Infrared Spectrograph (IRS) onboard Spitzer. We selected the sample from the European Large Area Infrared Survey (Oliver et al. 2000, Rowan-Robinson et al. 2004), which was carried out with the Infrared Space

Context: Near-Earth asteroid-comet transition object 107P/ (4015) Wilson-Harrington is a possible target of the joint European Space Agency (ESA) and Japanese Aerospace Exploration Agency (JAXA) Marco Polo sample return mission. Physical studies of this object are relevant to this mission, and also to understanding its asteroidal or cometary nature

We present the discovery of a new extreme high proper motion object (˜3.5 arcsec/year) which we classify as an ultracool subdwarf with [M/H] ˜ -0.5. It has a formal spectral type of sdM9 but also shows L-type features: while the VO bands are completely absent, it exhibits extremely strong TiO absorption in its optical spectrum. With a radial