Galaxy Morphology in the HST Frontier Fields Cluster MACSJ0416.1-2403 at Redshift z=0.4

Supervisor: Bodo Ziegler

Contact information: bodo.ziegler@univie.ac.at

Co-supervisors: Bianca Ciocan (PhD student), Miguel Verdugo (ELT postdoc)

Expected duration: 9 months

Project description & Goals:

Galaxy morphology, sizes, and stellar masses are important characteristics of a stellar system that can be determined from (multi-filter) photometry. We propose to exploit archival HST imaging of a cluster from the Frontier Fields campaign, MACSJ0416.1-2403 at redshift z=0.4, to measure galaxy structure and derive stellar masses. The HST imaging covers a wide region beyond the viral radius allowing an investigation of environmental effects. That way we can examine scaling relations like the Mass-Size relation at a cosmological epoch where cluster assembly peaks.

In addition, parts of the cluster were also observed by the VLT 2nd-generation 3D-spectrograph MUSE in the MUSCATEL campaign. The optical spectra are currently analyzed by PhD student B Ciocan to examine star formation, chemical enrichment, and internal kinematics of dozens of massive galaxies. There will be essential synergy between the two projects by combining the structural and kinematic properties of the galaxies.

Our group has year-long expertise with studying galaxy structure and the necessary tools and methods. The project is an extension, in some way, of a study by previous PhD student U. Kuchner. For the determination of structure we’ll mainly use a s/w package called PyMorph, which is a Python derivative of the heavily applied analysis tool GALFIT.

Working plan & Milestones (including final thesis):

  1. Introduction to the subject via literature and seminar presentations
  2. Retrieval of the archival HST imaging via MAST from STScI
  3. Training of the PyMorph tool
  4. Application of PyMorph to fit surface brightness distributions of galaxies to determine sizes and, if time allows, to perform a non-parametric analysis (like concentration and asymmetry) to study morphology
  5. Depending on project progress, training and derivation of stellar masses, else they will be derived and provided by the supervisors.
  6. Investigation of scaling relations like Mass-Size Relation and comparison to published other observational and numerical simulation studies.
  7. Write master thesis, and optional, present results at workshops.

Requirements / special skills: Good knowledge of extragalactic topics and good command of (oral and written) English. Experience with python programming would be an asset.

References:

Small selection:

more will be provided. 

Alternatively, we can perform the same analysis as outlined above based on James Webb Space Telescope multi-band photometry of the central regions of SMACS 0723 galaxy cluster at a redshift of z=0.39. This data will enable a detailed study of the structure and morphology of faint, low-mass cluster galaxies..