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Started supervision of a new bachelor thesis using JWST data

A new bachelor thesis under my supervision, with the title Spectral analysis of galaxies at high redshift (z<9) using the JWST, started at the Department of Astrophysics, University of Vienna. Logo Department of Astrophysics

Here is a short description:

Plenty of information about galaxy formation and evolution and their physical properties can be derived from galaxy emission lines (ELs). The interstellar medium (ISM) conditions such as the metallicity, ionization, and density, as well as the physical properties such as star formation rate and dust attenuation can be derived using ELs. EL ratio diagrams can be used to disentangle if the dominant ionizing sources in galaxies are star formation or active galactic nuclei (AGN).

Studying ELs at different redshifts enables an understanding of how the physical conditions of galaxies change over cosmic time. Since strong rest-frame optical ELs move to the (near-)infrared at higher redshifts, James Webb Space Telescope (JWST) spectroscopy is very useful to analyse rest-frame optical ELs of galaxies up to z=9.

For the started bachelor thesis under my supervision, publicly available data from JWST will be used for a spectral analysis of high redshift galaxies.

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Christian Maier’s top 5 extragalactic astronomy publications

Here are Christian Maier’s top 5 extragalactic astronomy publications. Christian Maier’s main research interests in extragalactic astronomy include the evolution of star formation rates and metallicities of galaxies, and therole of AGN and (cluster) environment on galaxy evolution and on quenching. These topics are part of Christian Maier’s  top 5 extragalactic astronomy publications.

Extragalactic Astronomy Publication 1 : Star-formation quenching of cluster galaxies as traced by metallicity and presence of active galactic nuclei, and galactic conformity

We explored 18 clusters from the Local Cluster Substructure Survey at 0.15 < z < 0.26, using spectra from the Arizona Cluster Redshift Survey Hectospec survey of about 1800 cluster members. As a result, we found that massive cluster galaxies suffer a rapid quenching of star formation, likely due to AGN triggered by the increasing ram pressure stripping toward the cluster center, which can compress the gas and fuel AGN.

Extragalactic Astronomy Publication 2: Cluster induced quenching of galaxies in the massive cluster XMMXCS J2215.9-1738 at z ∼ 1.5 traced by enhanced metallicities inside half R200

We explored the massive cluster XMMXCS J2215.9-1738 at z ∼ 1.5 with KMOS spectroscopy. As a result, the enhanced metallicities of cluster galaxies at z ∼ 1.5 inside 0.5R200 indicate that the density of the intracluster medium in this massive cluster becomes high enough toward the cluster center such that the ram pressure exceeds the restoring pressure of the hot gas reservoir of cluster galaxies.

Extragalactic Astronomy Publication 3: The Mass-Metallicity and Fundamental Metallicity Relations at z > 2 Using Very Large Telescope and Subaru Near-infrared Spectroscopy of zCOSMOS Galaxies

To explore the so-called “fundamental metallicity relation” (FMR) at z > 2, we used VLT-SINFONI and Subaru-MOIRCS near-infrared spectroscopy of 20 zCOSMOS-deep galaxies at 2.1 < z < 2.5. The galaxies show direct evidence that the SFR is still a second parameter in the MZR at these redshifts.

Extragalactic Astronomy Publication 4 (in collaboration with Lisa Kewley): The Cosmic BPT Diagram: Confronting Theory with Observations

We used our theoretical models to derive a new redshift-dependent classification line diagram that utilizes the standard optical diagnostic line ratios.

Extragalactic Astronomy Publication 5: Mass and Environment as Drivers of Galaxy Evolution in SDSS and zCOSMOS and the Origin of the Schechter Function

We explored the simple inter-relationships between mass, star formation rate, and environment in the SDSS, zCOSMOS, and other deep surveys. A purely empirical approach was taken to identify those features of galaxy evolution that are demanded by the data. We then explored the analytic consequences of these.

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Galaxy evolution and the quenching of star formation

What causes the death of galaxies? Is it nature or nurture? The new James Webb telescope combined with ground-based VLT data  provide new insights in  galaxy evolution and the quenching of star formation.

The new JWST (James Webb Space Telescope) data combined with KMOS and MUSE data from VLT are a powerful tool to study the evolution of galaxies and the cessation of star formation. Many of the JWST and MUSE observations (e.g., Abell 370) are publicly available, ready to be used for data analysis.

Galaxies in clusters Continue reading “Galaxy evolution and the quenching of star formation”