We report ROSAT observations of two molecular clouds previously unstudied in the X-ray band, examining the possibility that X-rays can serve as tracers of star formation at distances >∼ 1 kpc. The targets are the molecular clouds associated with the Monoceros R2 reflection nebula (d = 0.8 kpc) and with the Rosette giant HII region (d = 1.5 kpc). In both cases, the PSPC images show point sources...

SPKI is a certificate-based framework for authorisation in distributed systems. The SPKI framework is extended by an iteration construct, essentially Kleene star, to express constraints on delegation chains. Other possible applications, not explored in the paper, include multidomain network routing path constraints. The main decision problems for the extended language are shown to correspond to...

A general treatment of disk star formation is developed from a dissipative multi-phase model, with the dominant dissipation due to cloud collisions. The Schmidt-Kennicutt law emerges naturally for star-forming disks and starbursts. We predict that there should be an inverse correlation between Tully-Fisher law and Schmidt-Kennicutt law residuals. The model is extended to include a multi-phase t...

Recent observations have discovered star formation activities in the extreme outer regions of disk galaxies. However it remains unclear what physical mechanisms are responsible for triggering star formation in such low-density gaseous environments of galaxies. In order to understand the origin of these outer star-forming regions, we numerically investigate how the impact of dark matter subhalos...

We present high spatial resolution BIHK@-band imaging of a sample of ultralu(FWHMB 0A.3È0A.8) minous infrared galaxies ULIGs) with ““ cool ÏÏ mid-infrared colors (L ir[ 1012 L _ ; ( f25 km/f60 km\ 0.2), which select against active galactic nucleusÈlike (AGN-like) systems, a complementary sample to the ““ warm ÏÏ ULIGs of Surace and coworkers. We Ðnd that all of the cool ULIGs are either advance...

Abstract We construct a catalog of star clusters from Hubble Space Telescope images the inner disk Triangulum Galaxy (M33) using image classifications collected by Local Group Cluster Search, citizen science project hosted on Zooniverse platform. identify 1214 within imaging footprint Panchromatic Andromeda Treasury: Extended Region (PHATTER) survey. Comparing this to existing compilations in l...