Bob Watson's Home Page
I'm a post-doc working in the Radio Astronomy technology group of the
Jodrell Bank Centre for Astrophysics, University of Manchester. Over the
past 20 years or so I have been involved in the design, construction,
installation, control, observations and analysis of the various CMB
anisotropy experiments in which Jodrell Bank have had sited out at the
Izaña Observatory of the Instituto de Astrofísica
de Canarias (IAC) in
Tenerife, Spain. Now I'm back in Manchester building a general CMB data
reduction pipeline to be used mainly for QUIJOTE and C-BASS data.
The next goal of CMB experiments is to measure the polarized anisotropy signals which give even more cosmological information. The ultimate quest to find evidence for the tensor modes (long wavelength gravitational waves) created by inflation. Thereby providing strong evidence for inflation and put limits on it's nature. This will prove to be the most challenging experimental task to date as not only does it require an order of magnitude more sensitivity, but also in the presence of strong foregrounds and schematics.
One way to go is with interferometers due to their strong rejection of systematics (although they have a few of their own). Corrugated horns have the cleanest and simplest beams as compared to the mirror systems of current B-mode experiments and so are less affected by the systematic errors which limit these instruments rather than their raw sensitivity. The problem is correlators for these sort of high N element array is expensive and needs big international collaborations such as ALMA and SKA, but there might be a niche for relatively small compact arrays. A quasi-optical approach is being developed for bolometers which avoids the N-squared pairing whereby the fringes are imaged on to an array of detectors and all common baselines (of which are are many in a compact regular array) are processed in parallel.
Almost a by-product of CMB astronomy is the study of galactic foregrounds, which although a nunance for the CMB is a fasinating topic of it's own. Especially the mysterious anonmalous microwave emission which follows infrared dust, but should not be detectable at centermeter wavelengths. It looks to be caused by tiny dust grains or big molecules spinning at several gigahertz. Tenerife radiometer data suggested there was a large source in the Perseus region and IAC's COSMOSOMAS data pinpointed it to the Perseus molecular clould and now we have followed it up with VSA data.
The new Big brother to the COSMOSOMAS experiments will soon be online with a JBCA 30GHz front-end module and Manchester designed optics and horn designed and manufactored here. This path-finder instrument for a B-mode and foregrounds telescope working at 11,13,15,17,19 and 33GHz.
We were part of the CLOVER B-mode experiment it which we were going to be involved in the low-level data analysis of the raw 97GHz data as it arrived in the UK from Chajnantor, Chile. Sadly due to funding differcultiesthis project was closed and it remains to be seen if anything salvaged for a new experiment
Tenerife ExperimentI was sent out to Iza&htilde;, Tenerife as an eager M.Sc. student to take data for three months with some strange large horned 10GHz radiometer with a wagging metal plate (laughingly called a "mirror"). After various other experiment (5degree 10GHz, 15GHz, 33GHz and 33GHz interferometer (16.7 and 32 wavelength baselines) and 16 years later I was still there.
VSAThen Very Small Array happened, which I ran and maintained in Tenerife as well.
COSMOSOMASAt the same time COSMOSOMAS was happening. I wrote the acquisition system twice (about 4 months solid in C with Bison and flex and then about 2 weeks in Python with a bit of C).
Since my main focus has been on the acquisition and offline analysis software, which has developed into a strong interest in Linux, Java (see Moon applet), perl and currently python (and open source software in general).