Research at Bayfordbury Observatory
A glympse at the kinds of research programs taking place at Bayfordbury.
Research projects are on-going at Bayfordbury, in conjunction with the University's Centre for Astrophysics Research (CAR) and the Centre for Atmospheric and Instrumentation Research (CAIR) - both deprtments of the Science and Technology Research Institute (STRI) at the University of Hertfordshire.
As a state-of-the-art research facility, we currently have a number of interesting programs being run out of the Observatory.
Examples of research programs:
Here are some examples of the kinds of research being done from our facility:
Detection of tropospheric desert dust
- Mineral dust in the atmosphere is now acknowledged to be an important source of nuclei for the growth of cold clouds such as cirrus.
- Surprisingly, dust from deserts such as the Sahara can travel over very large distances.
- The Lidar and sun photometer at Bayfordbury are used to detect the presence of mineral dust in the atmosphere.
Cirrus climatology from ground-based remote sensing
- Cirrus clouds are thin, could clouds composed of ice crystals.
- Cirrus clouds have significant influence on climate as they influence the radiative balance of the Earth's atmosphere, and somewhat counterintuitively can have an overall warming effect.
- Climate models must therefore accurately represent cirrus clouds.
The radiometers, lidar and all-sky cameras at Bayfordbury are used to determine the occurrence and radiative influence of cirrus clouds, for comparison with the Met Office numerical models.
- Polarimetry is a technique frequently used in astronomy, especially to characterize the properties of interstellar dust.
- Terrestrial applications of polarimetry are less well developed.
The Specpol polarimeter at Bayfordbury is used to characterize the properties of cirrus clouds in the atmosphere, by measuring the polarization of scattered light across a broad spectrum of infrared wavelengths.
Multi-Bandwidth Monitoring of Cataclysmic Variables Identified by SuperWASP
The SuperWASP survey to find exoplanets also detected some binary stars.
In a binary system known as a Cataclysmic Variable (CV) consisting of a white dwarf orbiting close to a red giant, the red giant loses some of its matter causing a regular flare up of activity. This material initially orbits the white dwarf in an accretion disc. These interactions can cause very large changes in the optical brightness.
Several CVs have been identified by the SuperWASP team. A new research project just started my MSc student Peter Beck at Bayfordbury will obtain many brightness measurements for a number of these CVs over many orbits; a light curve will then be produced for each binary star by plotting the brightness against time and then compressing it into a single orbit.
As Bayfordbury is uniquely able to simultaneously robotically control five telescopes, the plan is to use each telescope to record brightness at a different optical bandwidths. Five linked light curves will be generated for each CV and used to investigate the interactions in far greater detail than has been achieved with SuperWASP.
Cirrus detection through infrared radiometry
PhD student Paolo Dandini is currently researching cirrus detection through radiometry using the Heitronics KT15II infrared radiometer, and detecting halos in AllSky camera images using image detection techniques.
In the coming months a more quantitative analysis will be done by using data from the solar photometer to obtain the cloud optical depth, and a further two new radiometers will be installed at Bayfordbury which will be able to measure short and long wave fluxes at the ground. These measurements in particular will be compared to the high resolution weather prediction model calculated by the Met Office.
High Sensitivity Solar Polarimetry
The measurement of the degree of polarization present in the solar disk is challenging because of the very small values averaged over the disk. In earlier work by J.C Kemp fractional polarizations of ~2xe-7 over the whole solar disk were measured with a photo-elastic modulator based polarimeter at high altitudes.
A similar instrument has been recently constructed at the university's Centre for Atmospheric and Instrumentation Research for measuring very small polarizations from the sun but with an emphasis on detecting the polarization resulting from atmospheric scattering of cirrus clouds and atmospheric dust.
The instrument is currently installed in a new robotic dome at Bayfordbury and will be operated remotely by Prof. Bill Martin during clear weather to record polarization data over the long term.
Preliminary results indicate fractional polarizations of ~2xe-5 linear polarization and ~1e-7 circular polarization are typical of the Bayfordbury site during clear weather without significant dust but these values are superimposed on a ‘pedestal’ of azimuthal polarization from Rayleigh scattering of about 1e-4. The latter was not observed by Kemp due to the way their data was processed.
The Off Ecliptic Solar System Object Search
- The Solar System is full of objects including asteroids and comets.
- Most of these lay in the plane of the Solar System, the Ecliptic, and a small number pose a threat to Earth, hence there a number of surveys to identify potential hazardous objects.
- Due to the fact that most objects are on the Ecliptic, the majority of surveys for Solar System focus on this region.
Using the 40cm robotic Iain Nicolson telescope we are searching an area of sky away from the ecliptic for Solar System Objects. Objects in this region of sky, although a lot rarer, are more likely to be undiscovered and may possibly be objects from outside the solar system.
The B250 Survey
- In 2011-12, former student Sam Richards, now at the University of Sydney, undertook a survey of 600 Galaxies using the 40cm CKT robotic telescope.
- Building on this work, we are undertaking a survey of 250 candidate galaxies looking for supernova - the sudden increase in a star's luminosity as it blows itself apart.
- Supernova are rare events, happening only once per 100 years in any one galaxy. However, they are a vital part of galaxy evolution and are a required process for life.
- Using the 40cm Meade Robotic Telescope, we are attempting to make a first detection of a supernova.
Additionally, and perhaps more importantly, we will be monitoring supernova from first detection thereby identifying both the type of supernova and potentially the nature of the progenitor star.
Long term monitoring of Supernova in nearby galaxies
- Supernovae are the dying gasp of massive stars.
- They occurr at the end of their lives when, due to a lack of fuel, they are no longer able to support themselves.
- The star collapses forming a super dense neutron star at its centre.
- The formation of the neutron star blasts it apart in an explosion so energetic, that it may be as luminous as its entire host galaxy for several months.