The Leiden/ESA Astrophysics Program for Summer Students (LEAPS) 2017
Projects list 2017
Update: 31, January 2017
These are the proposed research projects for LEAPS 2017. Please note that not all
projects will go ahead and some may still be added in the near future. Final funding decisions
lie with the Faculty sponsors. And please make a note that if you are interested in an ESA project,
to check if your state is an ESA member or affiliate state.
Project list (as of Jan 8 2017):
How the monsters were made: unlocking the formation of the most massive black holes in the Universe with LOFAR
Luminous high-redshift radio galaxies are spectacular objects and prime laboratories
for studying the formation and evolution of massive galaxies and supermassive
black-holes in the early Universe. These radio-loud active galactic nuclei (AGN) are
known to reside in the most massive galaxies in the Universe and were likely some of
the first galaxies and supermassive black holes to form.
In this project you will have the opportunity to combine brand new observations from
the Low Frequency Array (LOFAR) radio survey with a wide range of multi-wavelength
datasets to find and characterise this important population. As the deepest ever
radio continuum survey, the unique dataset provided by LOFAR makes it possible to detect
large numbers of these extreme sources and will allow us study the different modes of
black hole accretion out to unprecedented distances, providing critical constraints on
models of black-hole formation and AGN unification theories.
Shapes and sizes of Solar System small bodies
Type of project: Observational, asteroids, photometry
Asteroid size is a very important physical parameter, since its accurate determination
would give a better estimation of their densities. Additionally, the asteroid shape is
an essential input to thermo-physical models in order to derive physical properties of
the surface of these small bodies. How do asteroid surfaces look? How rocky are they?
The determination of asteroid physical properties is crucial to construct a “map” of
the distribution of material in the main asteroid belt and link the recovered meteorites
with the asteroid parent bodies, which disrupted and sent material to Earth. Asteroids
spin around their axes with periods of a few minutes up to tens of hours! The construction
of asteroid shapes leads to the determination of their rotational axes. This, in
combination with the orbit of the asteroid around the Sun can show whether the asteroid
is slowly drifting towards the Sun or at larger heliocentric distances. This project will
give access to observational data obtained from ESA-funded telescopes in Mediterranean.
The student will be focused on the refinement/finalization of astronomical photometry
software and/or its application on the analysis of the astronomical images to measure
the light flux of the asteroid targets. In special cases it will be possible the
co-observation of the asteroid targets, during the summer period. Experience in
simple software development or use of telescopes would be appreciated.
During this project, we will explore astronomers’ points of view on different aspects
of their attitude towards public engagement (PE) initiatives, their level of confidence
in taking part in PE activities, their perception of the public and their peers and the
value of education and public outreach at their institution. We will also study some
potential changes that are needed to be made in order to improve the astronomers'
participation in EPO and how these changes can be implemented.
Understanding how the most massive stars in our Galaxy are formed
Type of project: Observational, star forming regions using a radio-telescope
The most massive stars in our Galaxy (with masses greater than 8 times the mass of
our Sun) end their lives quite spectacularly when they become supernovae or black
holes. Because of this, they are the main contributor to the chemical enrichment and
energetic input in the Galaxy. However, despite their importance we still do not
fully understand how these massive stars are formed and how they impact their
immediate environment as they evolve. To understand this, we need to study the earliest
stages of the formation of a massive star.
In this project we will use observations of a sample of 12 regions of massive star
formation taken with the Atacama Large Millimeter/submillimeter Array (ALMA). ALMA is
a revolutionary telescope compose of 66 antennas, located in the Chajnantor plateau in
Chile. The 12 objects observed with ALMA have the perfect conditions to start forming
massive stars but no evidence of active star formation has been found within them,
suggesting we are witnessing the very earliest stages of massive star formation. The
analysis of this unique dataset is going to be key to determine what is the physical,
chemical and kinematical structure of the places where massive stars are born. The
student working in this project will be required to analyse the density structure of the
dust within these region using statistical tools. Experience in Python programming will be
The solar atmosphere is a highly dynamic environment; the magnetic fields, which dominate
the motion, are continuously reconfiguring, bringing the plasma along for the ride.
This results in fascinating features and activity, such as filaments and coronal mass
ejections (CMEs). In order to better understand these transient objects, a technique has
been developed which allows us to peer into the internal structure of the plasma and
uncover the density and mass distribution, as well as give estimates of total ejection
masses. The aim of this project is to conduct analysis of the internal mass structure of
a large number of filaments across their lifetimes. By comparing density maps with
information about the underlying magnetic field evolution, a deeper insight into
formation mechanisms may be gained, and typical eruption masses will be examined in order
to begin to dissect the anatomy of CMEs. The student will observe the solar atmosphere
over the past decade and search for suitable targets, and will be provided with several
command-line tools with which to conduct the analysis itself. This is an exciting project
for someone who wants to learn more about the stunning activity of the Sun, gain experience
in data processing using interactive programming, and enjoy some freedom in choosing the
specific focus of the project. The work will hopefully yield a publication in a
Planets-Disk Interaction in the Early Solar System: Formation of the Oort Cloud
and Santiago Torres
Type of project: planetary system dynamics, theory and simulations
Jan Hendrik Oort proposed in 1950 the existence of the cometary cloud
that surrounds the Solar System, but its formation remains unclear.
In several studies it has been argued that the Oort cloud formed in
the early stages of the Solar System, shortly after the giant planets
formed. Jupiter, in particular, would have cleared the debris around
its orbit and ejected the material into very elongated orbits.
Approximately 8% of this material could have remained bound to the
Solar System, the rest was ejected into the interstellar space. These
studies are based on N-body simulations that only take Jupiter into
account. The other giant planets are ignored, and the external
perturbations by stars and the Galactic tidal field are ignored. The
Galactic tidal field is important, however, in order to circularize
the orbits of the ejected material.
We want to test the hypothesis that 8% of inter-planetary material
formed the basis of the Oort cloud, and to what degree the orbits of
the young Oort cloud objects can be circularized by the Galactic tidal
This study will be done by performing simulations of the early
evolution of the Solar System including the giant planets and the
Galactic tidal field.
Supervision will be done by postdoc dr. Maxwell Cai and PhD student
Santiago Torres, under the supervision of prof. Portegies Zwart.
Aerosol characterization above California using the data of the test flight of the prototype SPEX instrument
SPEX (Spectropolarimeter for Planetary EXploration) is an innovative, high precision,
multi viewing angle spectropolarimeter for the characterization of planetary atmospheres.
It can measure the flux and the degree and direction of linear polarization of sunlight
that has been scattered within a planetary atmosphere from 400 to 800 nm.
In orbit around Earth, SPEX can perform multi-angle, multi-wavelength measurements
of intensity and polarization, in order to characterize aerosol and cloud particles in
the Earth atmosphere, with the overall goal to reduce the large uncertainty on the
aerosol direct- and indirect effects on climate. The effect of aerosols on climate
represents the largest reported uncertainty in the most recent assessment of the
Intergovernmental Panel on Climate Change (IPCC). This uncertainty severely hampers
future predictions of climate change [https://www.sron.nl/earth-instrument-development/spex].
In 2016, a test flight with a development model of the SPEX instrument was performed
above California using the high altitude flying ER-2 airplane. The raw instrument data
has been processed to extract the degree of polarization and depth of polarization across
a range of wavelengths. This information can be used to determine the refractive index of
the particulates in the atmosphere. In turn, the refractive index can be used to determine
the particle type, e.g. sea salt or soot. The goal of the summer project is to develop a
method to determine the refractive index per pixel and perform the aerosol classification
using the real measurement data above California.
We live in a molecular universe! Nearly 200 molecules have been identified in interstellar or circumstellar clouds. The large part of these molecules containing carbon (C), which is one of the building blocks of the life as we know it. All the interstellar molecules are made of few (less than 15) atoms, the only exception being the buckminsterfullerene molecule, the most stable member of the fullerene family, which contains 60 carbon atoms.
The detection of this molecule prompt many questions: how does C60 form in the ejecta of dying stars? How does it interact with photons and cosmic rays? Why there is a big jump, from 15 to 60 atoms, in the mass distribution of interstellar molecules? Are other smaller or larger members of the fullerene family present in interstellar and circummstellar clouds?
The project proposed here is to characterise the infrared vibrational spectrum of other type of fullerene molecules using theoretical methods and look for their signature in infrared spectrum of planetary nebulae and photodissociation regions.
The role of dust in star formation: A spatially resolved perspective
Dust is a fundamental constituent in galaxies, that is both a seed for, and a by-product
of, massive star formation. While we have a better understanding of global properties of
dust in galaxies in different galaxy environments across cosmic time, the distribution of
dust within galaxies, or the spatial properties of dust, and its link to star formation
remains largely a puzzle. This is key to understanding the connection between different
modes of star formation within galaxies (e.g. compact or diffuse star formation, bursts
of star formation etc.) and the production, destruction and distribution of dust, which
will in-turn provide much needed insights into the role of dust in advancing star
formation across a disk of a galaxy.
There are now a number of on-going observational campaigns, such as SAMI and MaNGA
surveys, aimed at obtaining spatially resolved information for large samples of galaxies.
This project will make use of a unique sample of galaxies observed in the SAMI survey,
for which we also have multi-wavelength (from far-UV to far-IR) global information,
to investigate spatially the relationship between dust and star formation in galaxies in
a range of different galaxy environments and types.
Water makes up a large fraction of our own planet. Yet, the mechanism that initially
delivered that water to Earth is still one of the major questions in astronomy and
planetary sciences. One way to investigate the mechanism is to observe and quantify
water toward objects that are on their way to form their planetary system.
This project will use the combination of interferometric observations and radiative
transfer modelling of water lines to quantify the water content of young
proto-planetary disks. The planetary system will eventually be formed in these disks.
Thus, the quantification of the water content will provide constraints on how and when
water is delivered to Earth size bodies.
Search for diffuse radio emission from galaxy clusters in LOFAR Tier-I survey data
Type of project: simulation plus observational type project on galaxy clusters
Clusters of galaxies are the largest gravitationally bound structures in the Universe.
Galaxy clusters form through a sequence of mergers of sub-clusters. Observations with
X-ray and radio telescopes reveal the co-existence of both thermal and non-thermal
components of the intra-cluster medium. However, the number of clusters that are detected
in radio band is far less than those reported by X-ray observations. A possibility is that
the diffuse radio emission in most clusters is naturally faint and is below the detection
limit of the current radio telescopes. Upcoming low-frequency radio surveys (e.g., LOFAR
Tier-I, MWA) are expected to significantly increase the number of clusters detected in
the radio. However, an optimal strategy to search for the faint diffuse emission is
still unclear, especially for projects that aim to map a large area of the sky such as
the LOFAR Tier-I and MWA GLEAM surveys. The aim of this LEAPS project is to develop a
robust, efficient strategy to detect diffuse radio emission in the LOFAR Tier-I survey
data. The work involves literature study (e.g., on radio interferometry), developing
strategy (on either a group or individual), writing code (e.g., python, bash, C++),
learning common radio packages (e.g., CASA, BBS, DPPP, PyBDSM), and testing the procedure
on real LOFAR data.
The optical properties of far-IR selected galaxies
A wide variety of multi-wavelength data (from the ultra-violet to the far- infrared)
is available for the galaxies that lie in the CANDELS survey fields from both ground
and space-based observatories. This allows us to study the properties of galaxies as well
as galaxy evolution at a peak epoch in the formation of galaxies (z~2) in great detail.
Particularly interesting are those dusty galaxies that actively form large amounts of stars
or even undergo a strong burst of star formation. Such galaxies are easily identified
through their emission in the far-infrared and consequential detection with the Herschel
Space Telescope. We followed up our sample of Herschel detected galaxies with optical
spectroscopy using the Multi-Object-Spectrograph on the Gemini- South telescope. The
resulting spectra of ~300 galaxies now need to be reduced and analysed (redshifts measured
and emission line properties analysed) and put into context with the existing photometric
observations. Data reduction will be carried out with the Gemini IRAF package. This
project will provide a good basis not only data reduction techniques for spectroscopy as
well as the analysis of spectroscopic data. We are looking for a highly motivated
student interested in galaxy evolution studies and willing to work in the framework of
an international collaboration.
A giant LEAP: stepping through lookback times to directly calibrate the Lyman-alpha emission of young galaxies
The Lyman-alpha (Lya) emission line is the strongest spectroscopic feature in star-forming
galaxies in the early Universe (z>2). As such, Lya has been used to discover galaxies that
are even fainter than those observed in the Hubble Deep Field. However, due to its
sensitivty to neutral hydrogen and dust, the fraction of produced Lya photons that we
observe is unknown. This severly limits the use of Lya as a tracer of galaxy properties
like the star formation rate.
Observations now indicate that the majority of Lya photons escape at large distances
from galaxies. However, the exact escape fraction or how this depends on galaxy properties
is not well understood. This is because it has been challenging to measure escape
fractions accurately, mostly due to the lack of well-understood spectroscopic features such
as Halpha. The proposed LEAPS project will use new data from a specially designed
experiment to measure the Lya escape fraction directly for a large sample of galaxies in
well defined redshift-steps. With these measurements, it will be possible to determine how
the Lyman-alpha escape fraction depends on galaxy properties and the distance from galaxies.
The project involves the reduction and analysis of deep photometric data in the best
Galaxy image modeling using Shapelets and sparse techniques
Galaxy images are sometimes decomposed in a special orthonormal basis called the Shapelets
[1-2]. The Shapelet-decomposition describes the galaxies to a good extent and has remarkably
good mathematical properties. Light from distant galaxies are lensed gravitationally by
clusters of galaxies and by the large-scale structure of the Universe and this introduces
a coherent shear in the observed images of the galaxies. The imprint of this shear can be
found in every coefficient when expanded in the Shapelet basis [3-4], and hence the
decomposition can be used to estimate the lensing shear and in turn map the invisible dark
matter in the Universe! The Shapelet formalism also enables a simple way to deconvolve the
point spread function (PSF) from the observed galaxy images . While the infinite number
of Shapelets serve as a complete basis, due to noise in the images, pixelisation and finite
size of the images, only the low-order Shapelets are meaningful. The omission of the
higher-order Shapelets can have artifacts and no longer accurately describe galaxies when
they are highly elongated and/have have a complex morphology and substructures .
These artifacts can be minimized by employing a suite of Shapelets of different radii,
also referred to as compound Shapelets . Compound Shapelets form an overcomplete basis
and thus the decomposition is not unique. The student will work on determining the "best"
solution(s) given a set of shapelets and on the choice of the compound Shapelets themselves
to optimise the performance. The student will have an opportunity to learn and apply some of
the sparse optimisation tools and techniques. A basic background in astronomical imaging might
be helpful but is not necessary.
The goal of the project will be to measure, and interpret in astrophysical and cosmological
context, the angular clustering signal of galaxies in new wide-angle catalogues, such as the
Kilo-Degree Survey (KiDS), as well as those based on SDSS or WISE. The measurement will be
performed with publicly available tools, or software developed by the student, depending
on student's interests. The interpretation will consist in estimating such cosmological
parameters as the mean matter density of the Universe and large-scale galaxy bias, at
various redshifts and for various galaxy types. The project could be further extended using
other type of data such as from modern radio surveys, for instant LOFAR or SKA precursors.
Cosmic Ray Content of the Inter-Galactic Medium ? A multi-messenger approach
Cosmic rays (high energy particles) are a a hither-to poorly constrained
element of the physics and the energy budget of galaxy groups. Although
numerous production mechanisms for these particles exist (e.g star formation,
acceleration at shocks, dark matter annihilation) it is unclear to what extent
the inter-galactic medium(IGM) is permeated by these particles and what their
importance to I) the energy budget of the IGM of galaxy groups is, respectively
II) the (re-)ionization of the IGM may be.
The Galaxy And Mass Assembly survey in combination with the data from the
Fermi-LAT instrument provides an ideal resource to begin constraining these
questions empirically, by using information from across the electromagnetic
spectrum. In particular GAMA provides the basis for a highly complete galaxy
group catalog tracing the IGM of galaxy groups, while the gamma ray flux measured
by Fermi traces the cosmic rays interacting with the IGM. Furthermore, GAMA's
multi-wavelength coverage from the FUV-FIR/submm/radio provides information
about possible sources of cosmic rays such as star formation. This project will
initially focus on cross-correlating the available GAMA group and Fermi gamma ray
data to constrain the incident cosmic ray flux. Follow-up characterization of
potential sources may then be possible with the full GAMA survey data.
Information on the GAMA survey is available here:
Ultra-large scale observables in the EFT formalism of modified gravity
Upcoming cosmological experiments such as Euclid and the SKA will
allow us to probe large cosmological scales, where modified gravity
(MG) models possibly exhibit distinct signatures. The present project
aims at expressing ultra-large scale effects in the Effective Field
Theory (EFT) formalism and assessing the possibility to distinguish
different MG models with future galaxy and/or 21 cm surveys.
Determine the sensitivity of an infrared earth observation instrument
identify different in-flight calibration procedures for existing instruments
analyse the possible techniques and methods for the instruments under development
estimate the uncertainties and accuracies of the different methods
propose a detailed plan for an overall in-flight calibration plan
report your findings and collaborate with the other members of the team
Please note that the ESA projects are only available for students from ESA member or
The working language of the observatory is English, and students should
be sufficiently proficient in English to perform a research project.
(Austria, Belgium, Czech Republic, Denmark, Estonia, Finland, France,
Germany, Greece, Hungary, Ireland, Italy, Luxembourg, The Netherlands, Norway, Poland, Portugal,
Romania, Spain, Sweden, Switzerland, the United Kingdom and Canada). Students from
Bulgaria, Cyprus, Malta, Latvia, Lithuania, Slovakia and Slovenia (affilliate members) can also apply for ESA projects.