An interacting scalar field and the recent cosmic acceleration

In this paper it is shown that the Brans - Dicke scalar field itself can serve the purpose of providing an early deceleration and a late time acceleration of the universe without any need of quintessence field if one considers an interaction, i.e, transfer of energy between the dark matter and the Brans - Dicke scalar field.Comment: 10 pages, 2 figure

Near infra-red spectroscopy of V838 Monocerotis

Near IR, multi-epoch, spectroscopic and photometric observations of the enigmatic, eruptive variable V838 Mon in JHK bands are reported. One of the unusual features is the detection of several strong neutral TiI lines in emission in the K band. From the strength of these lines, the mass of the ejected envelope is estimated to be in the range 10e-7 to 10e-5 M(sun). The spectra also show the strong presence of the first and second overtones of 12CO bands seen in the K and H bands. The CO bands show a complex evolution. Deep water bands at 1.4 and 1.9 micron are also seen later in the object's evolution. Blackbody fits to the JHK photometric data show that V838 Mon has evolved to temperatures between 2400 - 2600 K by approximately 130 days after outburst. The spectra at this stage have the general characteristics of a very cool M giant.Comment: 7 pages, 5 figures, to appear in Astronomy and Astrophysic

Physical interpretation of constants in the solutions to the Brans-Dicke equations

Using an energy-momentum complex we give a physical interpretation to the constants in the well-known static spherically symmetric asymptotically flat vacuum solution to the Brans-Dicke equations. The positivity of the tensor mass puts a bound on parameters in the solution.Comment: 10 pages, RevTe