We describe calculations for the formation of icy planets and debris disks at 30–150 AU around 1–3 M⊙ stars. Debris disk formation coincides with the formation of planetary systems. As protoplanets grow, they stir leftover planetesimals to large velocities. A cascade of collisions then grinds the leftovers to dust, forming an observable debris disk. Stellar lifetimes and the collisional cascade...

We have identified six early-type galaxies at z > 2.8 in the central 5.76 arcmin Hubble Ultra Deep Field NICMOS region based on a pronounced broad-band discontinuity between the NICMOS F110W and F160W bandpasses. These galaxies have red observed optical and near-infrared colors (ABF775W−ABF160W ≥ 2) that cannot be explained entirely by dust reddening (indicating advanced age), and their luminos...

We present the results of a MOPED analysis of ∼ 3× 10 galaxy spectra from the Sloan Digital Sky Survey Data Release Three (SDSS DR3), with a number of improvements in data, modelling and analysis compared with our previous analysis of DR1. The improvements include: modelling the galaxies with theoretical models at a higher spectral resolution of 3Å; better calibrated data; an extended list of e...

Surface photometry detections of red and exceedingly faint halos around galaxies have resurrected the old question of whether some non-negligible fraction of the missing baryons of the Universe could be hiding in the form of faint, hydrogen-burning stars. The optical/near-infrared colours of these red halos have proved very difficult to reconcile with any normal type of stellar population, but ...

We derive the stellar and circumstellar parameters with two models: the classical constant density nebula model and a stellar wind model. Depending on the mass loss rate of the star the stellar wind model results in a range of valid values which can deviate from the classical model results. This is especially true for the elemental abundances which are for every valid stellar wind model larger ...

The deep, near-infrared narrow-band survey HiZELS has yielded robust samples of Hα-emitting star-forming galaxies within narrow redshift slices at z = 0.8, 1.47 & 2.23. In this paper, we distinguish the stellar mass and star-formation rate (SFR) dependence of the clustering of these galaxies. At high stellar masses (M∗/M⊙ & 2 × 1010), where HiZELS selects galaxies close to the so-called star-fo...

We present a detailed analysis of the Galaxy Stellar Mass Function (GSMF) of galaxies up to z = 2.5 as obtained from the VIMOS VLT Deep Survey (VVDS). Our survey offers the possibility to investigate it using two different samples: (1) an optical (I-selected 17.5 < IAB < 24) main spectroscopic sample of about 6500 galaxies over 1750 arcmin 2 and (2) a near-IR (K-selected KAB < 22.34 & KAB < 22....