We investigate the star formation activity in galaxy pairs in chemical hydrodynamical simulations consistent with a Lambda-CDM scenario. A statistical analysis of the effects of galaxy interactions on the star formation activity as a function of orbital parameters shows that close encounters (r 30 kpc/h) can be effectively correlated with an

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We report a multisite photometric campaign for the β Cephei star 12 Lacertae. 750 h of high-quality differential photoelectric Strömgren, Johnson and Geneva time-series photometry were obtained with nine telescopes during 190 nights. Our frequency analysis results in the detection of 23 sinusoidal signals in the light curves. Ten of those

We present the results from a Hubble Space Telescope ACS study of the supernovae (SNe) associated with gamma-ray bursts (GRBs) 040924 (z=0.86) and 041006 (z=0.71). We find evidence that both GRBs were associated with an SN 1998bw-like supernova dimmed by ~1.5 and ~0.3 mag, respectively, making GRB 040924 the faintest GRB-associated SN ever detected

We present time-resolved spectroscopy and photometry of the cataclysmic variable (CV) SDSSJ133941.11+484727.5 (SDSS1339) which has been discovered in the Sloan Digital Sky Survey (SDSS) Data Release 4. The orbital period determined from radial velocity studies is 82.524(24)min, close to the observed period minimum. The optical spectrum of SDSS1339

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