Santiago Internship Projects

*Interested students should contact the project owners 

 

Title: VLA low radio frequency emission in groups and clusters of galaxies

Contact/s: Marie-Lou Gendron-Marsolais, mgendron@eso.org

Abstract: Jets created from accretion onto supermassive black holes release relativistic electrons on large distances which strongly affect their environment. These particles emit synchrotron emission visible at ~GHz frequencies. The hierarchical merging of subclusters and groups also generates perturbations and constitutes a potential source of reacceleration for these particles. The proposed project will focus on deep, multi-band, multi-configuration, low radio frequency observations from the Karl G. Jansky Very Large Array (VLA ) of two unique systems: the nearby NGC 4472, dominant member of a galaxy group lying on the outskirts of the Virgo cluster, and Abell 2146, one of the rare clusters undergoing a spectacular merger in the plane of the sky. Both systems have recently been awarded deep X-ray observations, which have significantly help our understanding of their complex dynamical history. The project goal is to reduce, image and analyse the new VLA datasets in order to provide a complete portrait of the non-thermal emission frothe electron population of the AGN outflows in these systems.

Required skills/experience: Prior expertise in research and/or data reduction, as well as programming skills (Python), is desirable, but not necessary. The candidate should have good oral and written communication abilities, be willing to learn new skills and work independently.

Estimated duration of the project: Approximately 3-4 months

Title: Jet Properties of Blazars Observed by ALMA

Contact/s: Hugo Messias, hugo.messias@alma.cl

Abstract: For the purpose of flux calibration, ALMA monitors bright radio sources in the sky, many being Blazars, accreting super massive black-holes whose jets are oriented close to the observational line-of-sight. The goal of the project is to gather more high-energy photometry (in the X- and Gamma-rays spectral regime) in order to improve the characterization of the inverse-Compton component of the sources' spectral energy distribution and establish its relation with the synchrotron component.

Required skills/experience: Python (advantage: basics of super-massive black-holes)

Estimated duration of the project: 3-6 months

Title: NGC6240 CS(5-4) ALMA long-baseline imaging

Contact/s: Hugo Messias, hugo.messias@alma.cl

Abstract: In Treister et al. (2020), a highly detailed map of carbon monoxide (CO) was presented toward the merging galaxy NGC6240. This system is of high interest due to the presence of two super-massive black-holes in its centre. The same data-set also observed carbon monosulfide (CS) which should provide us with a view of the densest regions in the system, likely giving us a view of the clouds possibly harboring the conditions for stellar formation. This work aims to achieve science quality images and velocity maps of CS in this complex system.

Required skills/experience: Python (advantage: interferometry basics)

Estimated duration of the project: 6 months

Title: Environment of Radio Galaxies

Contact/s: Hugo Messias, hugo.messias@alma.cl

Abstract: The Atacama Compact Array (ACA) recently observed a set of 42 radio galaxies in the millimetre wavelength spectral regime. One of the goals of this project was to assess the environment within which these sources are found. By combining ACA and Spitzer imaging, this project aims to determine how much do radio galaxies trace large-scale structures in the first half of cosmic time.

Required skills/experience: coding language (c, c++, Python, Julia, ...; advantage: galaxy-evolution basics)

Estimated duration of the project: 6 months

Title: High-redshift Passive Disc Galaxies

Contact/s: Hugo Messias, hugo.messias@alma.cl

Abstract: In Messias et al.(2010, 2012) infra-red colours were found to be quite efficient in identifying disc galaxies in the early Universe already with low star-formation activity. This work aims to apply this technique to identify such galaxies in two of the most observed regions in the sky: the Great Observatories Origins Deep Survey North and South. Further characterization of their multi-wavelength spectral energy distributions will provide further evidence on their stage of evolution.

Required skills/experience: coding language (Fortran, c, c++, Python, ...; advantage: galaxy-evolution basics)

Estimated duration of the project 6 months

Title: Determining the Dynamical Model of a Lensed-Galaxy

Contact/s: Hugo Messias, hugo.messias@alma.cl

Abstract: In Messias et al.(2014, 2019) a lensed-galaxy was shown to be comprised by two merging galaxies quite distinct from each other. While one dominates the stellar-mass content in the merger, the lightest one is forming stars at a high-rate showing a high content of gas and dust. Using the dynamics of the gas in the latter, this work aims to assess its dynamical properties and put better constrains in the merging type (major or minor) we are observing.

Required skills/experience: coding language (c, c++, Python, Julia, ...; advantage: galaxy-evolution basics)

Estimated duration of the project:  6 months

Title: Obscuration Events in Evolved Stars

Contact/s: Claudia Paladini, cpaladin@eso.org, Peter Scicluna peter.scicluna@eso.org

Abstract: In 2019 the red supergiant star Betelgeuse generated a lot of interest and speculation when experienced a dimming event visible with naked eye. However Betelgeuse is not the only object exhibiting such kind of events. Almost 1/3 of the carbon-enriched asymptotic giant branch (AGB) stars, during their life, undergo episodes where extreme changes in their colors are recorded. In this project the student will reduce and interpret SPHERE data of the archetypal of C-rich Mira stars that underwent a dimming event, the carbon Mira R Fornacis,

Required skills/experience: Python programming language

Estimated duration of the project: 3 months

Title: Tomography of an hourglass: the interferometric view of the biconical outflow of R Crateris

Contact/s: Claudia Paladini, cpaladin@eso.org, Peter Scicluna peter.scicluna@eso.org

Abstract: A companion interacting with the circumstellar environment (CSE) is the most accepted explanation for the presence of asymmetric planetary nebulae (PN). In the previous phase of stellar evolution, on the asymptotic giant branch (AGB), evidence for this interaction was observed only in the CSEs of a handful of objects, and overall the mass-loss process from AGB stars is regarded as spherically symmetric. Within this project the student will interpret newly acquired VLTI interferometric data of the semi regular variable R Crateris using geometric and radiative transfer models. The data are already reduced and show strong departure from spherical symmetry which could be due to the presence of previously unseen companion.

Required skills/experience: Python programming language

Estimated duration of the project: 2 months

Title: VISIR at the heart of a triple system

Contact/s: Claudia Paladini, cpaladin@eso.org, Peter Scicluna peter.scicluna@eso.org

Abstract: The mass-loss process from evolved stars is a key ingredient for our understanding in many fields of astrophysics, including stellar evolution and the enrichment of the interstellar medium via stellar yields. In this project the student will analyze and interpret with radiative transfer coronography data taken with VLT/VISIR of an Asymptotic Giant Branch (AGB) Star. The object is one of the very few triple systems on the AGB so far known. The data will be able to shed light on the nature of the third companion. The modeling will help understanding how the presence of a companion interacts with the stellar wind in the race towards the formation -at the next evolutionary stage- of asymmetric planetary nebulae.

Required skills/experience: Python programming language

Estimated duration of the project: 2 months

Title: Exoplanet atmospheres: probing for molecular absorption.

Contact/s: Dr. Florian Rodler, frodler@eso.org

Abstract: Gaseous exoplanets at orbital distances just a few stellar radii away from their host stars ("hot Jupiters") represent unique laboratories for probing exotic atmospheric compositions. This project is dedicated to an analysis of different datasets (spectroscopy) that were taken of transiting exoplanets with the goal to probe these spectra for molecular absorption coming from the exoplanet atmosphere. Data were obtained at the 6.5m Baade Magellan telescope and the 10m GranTeCan telescope in La Palma. 

Required skills/experience: Enthusiasm & motivation, data reduction skills (IRAF or other), knowledge of spectroscopy, coding skills (python, C). Expertise in data analysis of transmission spectroscopy would be an asset. 

Estimated duration of the project: The project length would be 3 months.

Title: Precise radial velocities of planetary mass companions with SINFONI

Contact/s: Robert De Rosa, rderosa@eso.org

Abstract: Measuring the orbital architecture of planetary systems provides insight into their formation, and their dynamical evolution and stability. Only a handful of directly imaged planets have radial velocity measurements to-date given the challenging nature of the observation, but in each case the result had a high impact. With this project we are seeking to expand this sample by analyzing observations of the HD 106906 b planet taken with SINFONI, an integral field spectrograph on the VLT. This planet is at an extremely wide separation, and the visual orbit suggests it is on an eccentric and inclined orbit relative to the inner system raising questions regarding its formation pathway. A radial velocity measurement of this planet would allow us to confirm that the planet is actually gravitationally bound to the star, and to further constrain the eccentricity of its orbit. We will apply a novel data analysis technique developed for Keck/OSIRIS observations that can achieve a precision of 0.4km/s on sources of a similar brightness and spectral type. This is smaller than the range of radial velocities relative to the host star consistent with the visual orbit (±2km/s), and comparable to the uncertainty on the radial velocity of the host star (12.2±0.2km/s), suggesting a single measurement would help to further constrain the three-dimensional orbit of this system.

Required skills/experience:

- Experience with spectroscopic data analysis or a motivation to acquire the skill for their future studies/career.                          

- Experience with Python required (ideally with matplotlib and FITS file I/O).

- Experience with shell scripts or working from the command line would be a benefit.

Estimated duration of the project:  4 months

Title: Illuminating cold dust in evolved stars

Contact/s: Peter Scicluna, peter.scicluna@eso.org

Abstract: Asymptotic Giant Branch (AGB) stars are responsible for a significant fraction of the dust production in our galaxy. However, there are large uncertainties on exactly how much they produce, in part because the coldest parts of their outflows are very hard to detect. As part of the Nearby Evolved Stars Survey, we have performed deep observations of cold dust in AGB star outflows using the SCUBA-2 instrument at the James Clerk Maxwell Telescope, observing roughly 500 stars in unprecedented detail. You will work on processing the data and developing models to optimise the processing and interpret the outcome. This will improve our understanding of how much cold dust is in the outflow and how that compares to the hot dust. In turn, this will feed into understanding how the dust-production process varies with time, helping to understand the discrepancy between the amount of dust produced by stars and the amount present in the interstellar medium.

Required skills/experience: Familiarity with python and the terminal. Some knowledge of observations or models at infrared or sub-mm wavelengths would be useful, but is *not* a requirement.

Estimated duration of the project: Can be tailored to the student's interests and skills, but we expect a minimum of 6 weeks to be required.

Title: Artifact Free Protoplanetary Disk Imaging with Star-hopping

Contact/s: Zahed Wahhaj, zwahhaj@eso.org

Abstract: A new technique called star-hopping, introduced to the SPHERE exo-planet imager on the VLT, can obtain ADI artifact-free images of proto-planetary disks, for the first time. In usual, Angular Difference Imaging (ADI), the predominant method to image disks, any extended morphology is severely affected by self-subtraction artefacts, as PSF subtraction is indispensable in adaptive optics (AO)  imaging. We have recently obtained a star-hopping dataset from a SPHERE DDT on the famous 4-planet system, HR 8799 which has a debris disk. The detections of the planets and planetary spectra have been excellent and the data reduction led to some advanced tools (Wahhaj el al. submitted). However, more work needs to be done for reduction tools for the debris disk, particularly for disk feature detection accuracy. This project would be very suitable for a student: using star-hopping RDI to obtain the most accurate images so far of the dust disks in young planetary systems.

Required skills/experience:

- IDL or python programming.

- Interest in exoplanet imaging or spectroscopy.

- BA/BS in Science

Estimated duration of the project: 13 weeks 

Title: A systematic study of tidal disruption event properties

Contact/s: Thomas Wevers, twevers@eso.org

Abstract: Tidal disruption events occur when a star passes so close to a supermassive black hole that the tidal forces overcome its self-binding energy. As a result, the star is destroyed and part of the material is accreted, leading to transient multi-wavelength emission. However, so far the mechanism responsible for the luminous UV/ optical emission is not known and its properties are poorly understood. Recent advances in both detection rate and multi-wavelength follow-up have resulted in a significant number of tidal disruption events having well-sampled Swift UV/optical light curves. The aim of this project is to build a pipeline that analyses these light curves in a systematic way, including de-reddening, host galaxy light subtraction and blackbody fitting. Using these processed light curves we can investigate correlations between observable properties (e.g. blackbody temperature, radius) with fundamental properties such as the black hole and disrupted stellar mass.

Required skills/experience: Some code needs to be written, so familiarity with Python (or similar) is preferred. Knowledge of photometry would be useful, but is not required.

Estimated duration of the project: 3-6 months