László Szűcs

Max-Planck-Institute for
extraterrestrial Physics

Piszkéstető, Mátra Montains, Hungary

Welcome to my website!

I am László Szűcs (Hungarian pronunciation: [ˈlaːsloː ˈsyːt͡ʃ]), a postdoctoral researcher at the Max-Planck-Institute for extraterrestrial Physics (MPE) in Garching, Germany. My fields of research are astrophysics and astrochemistry. In particular, I am interested in comparing theoretical models of astronomical objects (based on our best physics and chemistry knowledge and certain assumptions) to what is observed, to quantify how well we understand them. I study a relatively broad spectrum of objects from star forming molecular clouds to planet forming dusty circumstellar disks. My main asset in this work is radiation transport modeling, a tool allowing us to link physical quantities (e.g. density, temperature, chemical composition) to observable quantities (i.e. flux density or brightness temperature).

Currently I work on a method to include large chemical networks -- required to model the diverse chemistry observed in the ISM -- to hydrodynamical simulations in a computational cost-efficient way.

How well does CO emission measure the H2 mass of MCs?

12th July 2016

Due to its high abundance and observability at radio wavelengths, CO emission is often used as an indicator for the physical characteristics (e.g. mass and virial state) of molecular clouds (MCs). In this work, I tested how the observational techniques, that are based on measuring CO emission, may recover the true masses of MCs. For this I analysed emission maps of hydrodynamic MC simulations. I found that the virial and XCO methods work well (within a factor of two) in contrast to the ¹³CO column density measurement, which underestimates the true mass by about an order of magnitude. Interestingly, the virial methos works even when the overall cloud is super-virial. This is due to a systematically lower virial parameter (i.e. closer to equilibrium) in the CO-emitting regions; in CO emission, clouds might seem (sub-)virial, even when, in fact, they are expanding or being dispersed. [arxiv,short]
Blasted by radiation

20th December 2015

Modern numerical simulations of star formation include an increasing number of physical processes (e.g. self-gravity, turbulence, radiation transport and stellar feedback) to reproduce the statistical properties of star-forming molecular clouds. When the chemistry and radiation propagation are taken into account, the observed appearance of real molecular clouds may also be reproduced. In collaboration with Thomas Bisbas (MPE), we imaged a simulated cloud dispersing under the radiation feedback of a newly born high mass star as the Herschel Space Telescope would see it (both in dust continuum and molecular line emission). The images were selected for the Max Planck Society's yearly advents calendar in 2015. [MPG,more]
The ¹²CO/¹³CO isotope ratio in molecular clouds

20th March 2014

I recently submitted the paper about the carbon monoxid (CO) fractionation chemistry in turbulent molecular cloud simulations. We were looking at how the ¹²CO/¹³CO ratio depends on the total, ¹²CO and ¹³CO column densities, and whether the simplification of a uniform ratio is a good approximation in observational studies or when infering emission from numerical simulations. We find isotope ratios largely consistent with available millimetre-wavelength observations, and a close correlation with the isotopologue column densities. The assumption of uniform ratio results in up to 40-50 percent error in ¹²CO column density/mass estimates form ¹³CO observations, and up to 50 percent error in the integrated emission of ¹³CO when infered from ¹²CO number density distribution. This can, however be corrected by a fitting formula we propose based on the correlation found in our simulations. [arxiv,short]
Herschel view on disks around low-mass stars

4th October 2013

A paper by Johan Olofsson and me as a coauthor about Herschel/PACS observations and the modelling of protoplanetary disks in the Chameleon-I star-forming region is now accepted. We found that mid-infrared observations are not reliable tracers of total dust disk mass around low-mass stars. This is because the disk around low-mass stars can be massive enough to became optically think in the inner few astronomical units. [paper,short]

links

My research is supported by the ERC project 320620 “PALs”.