Astronomical Targets

The installation of Bolocam at the Caltech Submillimeter Observatory be followed by the initiation of several key observing programs.

1.

Sunyaev-Zel'dovich effect; the interaction between the Cosmic Microwave Radiation (CMB) and the hot intracluster matter produces a measurable distortion of the CMB. At millimeter wavelengths it is possible to separate the thermal and kinematic components of the Sunyaev-Zel'dovich effect using bolometer array systems [Birkinshaw (1998) and references therein]. Sunyaev-Zel'dovich surveys of high-redshift (z > 0.2) galaxy clusters will produce peculiar velocity surveys covering larger volumes of the universe than ever before and trace the cosmic density field over unprecedented scales.

2.

Protostars and planet formation; stars and planets form inside molecular clouds. The temperature of the dust which is surrounding the stars is estimated to be 15 to 70 K. Millimeter wavelength observations can penetrate this dense cores of star forming regions to observe deeply embedded objects. The high sensitivity of the new cameras and the high mapping speed will produce unbiased surveys of extended dark clouds. It is going to be possible to estimate the star formation efficiencies, mass-accretion rates and evolutionary lifetimes.

3.

Primeval galaxies; early galaxies can be described as the progenitors of present-day galaxies These galaxies are in the process of assembling their mass through gravitational collapse and forming the first generation of stars. The UV radiation from young massive stars is re-radiated by the dust grains in the FIR (typically L_FIR/L$_{UV}\sim$10-100). At high redshift the FIR radiation ($\sim$ 30% of the bolometric luminosity) is shifted into the submillimeter and millimeter. The new generation of large bolometer arrays such as Bolocam will be instrumental in deep surveys to detect galaxy formation in the early universe. These surveys will allow to distinguish between the main different galaxy formation models, the Classical model where the spheroidal systems were formed in a rapid phase at an early time and the Hierarchical model where big systems where formed by the interaction of smaller galaxies.

Figure: The panel shows a impressive view of the Hubble Deep Field at 850 microns
(Hughes et al. 1998). Five sources associated  with individual high red--shift galaxies
(z of about 3) present fluxes higher than 2 mJy after 50 hours of integration.
This image was  obtained  with SCUBA on the JCMT.