The influence of shocks on star formation in the OMC1 Ridge

Observations are presented of the OMC1 Ridge (a narrow band of molecular gas containing high-mass embedded sources), in the transitions CN N = 2 - 1, 13CO J = 2 - 1 and 13S J = 5 - 4. Variations in velocities and line widths indicate that three distinct regions are present in the area mapped, and that at least one of these is rotating. The resulting shocks when these fragments collided will have compressed the gas to a density nH2~107-8cm-3, sufficient to trigger collapse and to explain the presence of high-mass stars at the edges of the cloud fragments, rather than in their cores. These observational results support theoretical predictions of the importance of collisions in star formation

X-ray variability of the quasar 3C273

Observations of the quasar 3C273 made during 1975-77 have shown that the X-ray flux varied on a time scale of several months. No similar variation was present in radio and optical data taken at similar times. If this variation results from luminosity variations of a central compact object, then an upper limit of ≤4 x 1017cm can be set on its dimensions

GENIE observations of small scale astrophysical processes in star forming regions and quasars

The VLTI/GENIE configuration will operate using at least 4 of the VLTI telescopes (and possibly with one or more of the AT telescopes in the future if adaptive optics become available on them). GENIE effectively can be thought of as a 'smart' coronagraph, enabling high dynamic range imaging to be achieved at moderate spatial resolution, with high rejection of the emission of a central bright point source. However, but this bright source rejection may only provide a rather moderate image quality (due to the few baselines and transfer function on the sky). Operated in this way, only limited image reconstruction is possible since classical radio and millimeter wavelength interferometry techniques are not directly applicable to the outputs of optical interferometers because the absolute phases are generally not measured. However, measurements of visibility and closure phase could lead to situations where image reconstruction becomes possible. This paper addresses the issue of whether there are areas outside of the exoplanet search where it might be able to make a useful impact on astronomy.Comment: Proceedings of the Genie-Darwin Workshop - Hunting for Planet

Why Labor Unions Have Grown Reluctant To Use the “S” Word. Global, High-Tech Economy Makes Striking Riskier As Membership Declines. A Sense of Shared Purpose, 1999

Newspaper article about strikes and the role of unions in strikes, The Wall Street Journal. Vol. 104, No. 118, December 16, 1999

Challenges in Demonstrating the Impact of Overconfidence in M&A Activity

Financial Economics,

A CO/ and IRAS study of Cometary GLOBULE:12

Observations of the J = 2 - 1 CO and C¹⁸O lines are reported towards the reflection nebula NGC 5367 in the head of Cometary Globule CG 12, which show it to be only the second example known to date of molecular outflow activity in such an object. The CO has a bipolar shape, centred close to the infrared source IRAS 13547-3944. This has a bolometric luminosity ~110 L⊙, and lies close to a 13.5 M⊙ molecular core whose kinetic temperature ~20K and diameter ~0.15 pc. This core appears virialised, and offset from the highest temperature material along the eastern edge of the dense gas - which is probably heated by the UV radiation of a nearby B4 star. A highly collimated (axial ratio ≥5) and low-luminosity molecular outflow originates close to this core, extends over a length of 0.9 pc, and contains ~0.05 M⊙ of outfiowing material. The structure of the outflow is discussed along with its relationship to the rest of the globule. This is an example of a relatively isolated low-intermediate mass star formation region, which is speculated to have formed as the result of a nearby supernova event 10 - 20 million years ago, and has to date converted about 20 percent of its gas mass into stars

Towards a Molecular Inventory of Protostellar Discs

The chemical environment in circumstellar discs is a unique diagnostic of the thermal, physical and chemical environment. In this paper we examine the structure of star formation regions giving rise to low mass stars, and the chemical environment inside them, and the circumstellar discs around the developing stars.Comment: 9 page PDF, 550 kbyte

The Curse of Being Clever

Stephen Leacock mentions in one of his essays the horseman who leaped into the saddle and galloped off madly in all directions. It would take a clever horse and a clever rider to do that, but Leacock was not necessarily being clever when he wrote it

Molecular line maps of the Galactic Centre Circumnuclear Disk

Prelimary results are discussed for a long-term programme carried out with the James Clerk Maxwell 15m Telescope, to map the structure and dynamics of the Circumnuclear Disc at the Galactic Centre in a wide range of millimetre and submilletre wavelength molecular line transitions