****examples of the previous year summer projects****

The LOFAR Pilot Survey for Nearby Radio Pulsars

Since December, and into the summer, we are taking pilot LOFAR pulsar-survey data. We expect to find roughly a dozen new radio pulsars even in this first batch. Data reduction and pulsar searching on the first data has begun; the student will help search these data for the dispersed, periodic radio bursts characteristic of  pulsars, look for candidate sources, and then compare with databases of known sources. The student could identify some of the first-ever LOFAR pulsar discoveries. Optionally, the student may investigate what candidate visualization techniques may improve both this LOFAR pipeline, and the similar V-FASTR fast transients project with the VLBA.

Characterizing the earth's ionosphere with LOFAR 

The topic to cover are ionospheric issues (and possibly beam issues), but with a clear scientific target. Observations to handle could be from (or related to) LOFAR commissioning observing project LEA128, or they could consist of preparatory observations for LOFAR's pilot survey, the Million Source Shallow Survey. The latter would either a series of short snapshot observations, or dealing with short time-slices from 6hr datasets. Multi-beamed observations may be useful for characterizing ionospheric issues. The exact scheme will depend on where the commissioning efforts stand in the early summer.

Prepare for Epoch of Reionization observations with LOFAR

The success of the LOFAR Epoch of Reionization (EoR) experiment relies on our understanding of foreground contamination, ionospheric distortions, RFIs, complex instrumental response, and noise. Therefore, the LOFAR-EoR team has 

(i) developed an end-to-end simulation of the experiment, which is used intensively for testing the cosmological signal extraction schemes; and

(ii) obtained/planned a number of LOFAR-EoR commissioning observations with aim to constrain the foregrounds, instrumental properties, and noise.

Here, we propose a summer student project aimed as a part of the LOFAR-EoR commissioning effort.  The project includes the following tasks:

- analysis of one LOFAR-EoR commissioning dataset (including calibration, effects of the beam, modeling of the sources in the field, and source extraction);

- obtaining the properties of the noise by taking the difference between the two subsequent frequency channels.

Testing the new VISIR pipeline with simulations

In context of the E-ELT mid-infrared instrument study METIS, the VLT mid-infrared instrument VISIR is undergoing a major upgrade, including an upgrade with novel Aquarius detector systems and an automatic image processing system, called pipeline. This pipeline should provide science-grade data products, removing all instrumental signatures, calibrating measurements in physical units with associated error bars. Essential is that no spurious features are introduced during the various processing steps, e.g. the image quality is preserved and not downgraded by the data processing algorithms.

After general functionality tests of the pipeline, performed by the ESO developers the next step, and a very important one, is the benchmark verification and detailed evaluation whether the requirements on the processing system are met. Such tests have to be done by means of simulations.

For example existing raw fits files of VISIR standard star observations in imaging and spectroscopy are used where exposures are replaced by simulated images or laboratory data as taken with the new Aquarius detector.  Those simulated raw data are run through the new ESO provided pipeline system. This allows, as outlined in a detailed test plan, to compare various parameters of the pipeline products (such as conservation of energy and flux, Strehl ratio, error propagation, ...)  against analytical results. For the summer project, we will focus on the spectroscopy.

Source-finding and parametrisation in large HI surveys

In order to prepare the upcoming large surveys with Apertif/ASKAP/MEERKAT, the need arises for reliable software to identify HI sources and to parametrise them as best as possible, in real time, on the fly. While there are quite some efforts in this direction, a final general-purpose detection- and parametrisation pipeline has not been found yet. The purpose of this summer-studentship is to engage the student in this effort.

A large fraction of sources will be unresolved or barely resolved and the summer student will test a set of pre-defined source-finding algorithms working on basically two data sets to improve our knowledge on how to identify and parametrise barely resolved sources. Data from the EBHIS survey, conducted with the Effelsberg 100m dish, will be searched by eye and by comparing those results with the outcome of different source finding algorithms (Duchamp, Serra, Beta test, Kuiper test), and advantages and disadvantages of the techniques have to be identified. Consequently, basic parametrisation techniques will be tested, partly inherent to the source finders.  EBHIS is particularly suited for this test, since for lots of the unresolved galaxy disks (at the Effelsberg resolution of 9 arcmin) complementary high-resolution data already exist. A goal, which may be reachable with a summer student familiar with programming, would be to explore a solution combining the virtues of all the mentioned source finding algrorithms.

From a science point of view, the project may well see if the EBHIS survey contains isolated HI objects at the outer regions of the Local Group (Leo T analogs). Such a search is one of the main scientific aims of large-area surveys such as EBHIS, but also the Apertif and ASKAP surveys.

Atomic Hydrogen in Galaxy Cluster Cores

The aim of the project is to search for neutral atomic hydrogen (HI) in the centers of six clusters of galaxies. This search is done via observation of HI in absorption against the central radio galaxy.

The cores of galaxy clusters are gas-rich and violent environments that represent a crucial test for many aspects of galaxy formation and evolution and, in particular, to understand the effect of the central active galactic nuclus (AGN) on the intracluster medium of these systems.

The project will include the reduction and analysis of new data obtained with the Westerbork Synthesis Radio Telescope (WSRT). The observations will be used to constrain the mass and dynamics of the HI gas in these clusters.

All data will be available by the summer and one of the targets has already been detected in HI. Discovering HI in all targets would more than double the amount of currently known clusters cores with HI detections.

Supporting data at other wavelengths is available to perform detailed comparisons between the HI gas, the ionised/molecular gas, and the AGN. In particular we have optical integral field spectropy that can be used to study the detailed physics of ionised gas in these clusters.

EVN imaging of the rotating-wind detected quasar PG1700+518

Rotation Measure Gradient Reversals test Magnetic Tower Models