Event Calendar

Location: MP 15th Floor Conf Room

Title: ROHSA: Regularized Optimization for Hyper-Spectral Analysis – Revealing the properties of turbulence in the Warm Neutral Medium

Abstract: Star formation in galaxies is strongly linked to the physical processes that govern the evolution of the interstellar medium. Stars form by gravitational collapse of dense and cold structures in molecular clouds but the process that leads to the formation of these overdensities is still unclear. One key element seems to be related to the efficiency of the formation of the Cold Neutral Medium (CNM). Several studies have aimed at understanding the production of the CNM through the condensation of the Warm Neutral Medium (WNM) in a turbulent and thermally unstable flow using numerical simulations. In general, these studies indicate the presence of a significant fraction of the mass being in the thermally unstable regime. However, the thermodynamical conditions of the gas remain largely unexplored from the observational point of view. To go further, and really compare with numerical simulation that are, for now, under constrained by observation, it is mandatory to map the column density structure of each phase and study the spatial variations of their centroid velocity and velocity dispersion. This calls for methods that can extract the information of each HI phase from fully sampled 21 cm emission data only. I will present ROHSA, an original Gaussian decomposition algorithm based on a multiresolution process from coarse to fine grid using a regularized non-linear least-square criterion to take into account simultaneously the spatial coherence of the emission and the multiphase nature of the gas. This method allows us to infer a spatially coherent vision of the three-phase neutral ISM. Based on these results, I will discuss the new constraints that are obtained with a high-level of confidence on the thermal and turbulent properties of the WNM.

Location: MP1318

Weekly paper discussion focussing on pulsars, compact objects, and propagation effects.

For a list of upcoming discussions, see:
https://docs.google.com/spreadsheets/d/1KEyKBCmeGFUmMoiYKuHEDguCv9OOrEZqm3A6GM1Slk0/edit?usp=sharing 

If you would like to sign up for the presenter rota, email: simard@astro.utoronto.ca Location: CITA lounge

Location: MP1318A

The schedule of speakers: https://tinyurl.com/cosmo-rota  
Location: 15th floor conference room

Title: The Mystery of Methane on Mars: Fact, Folly or Figment?

Abstract: From the first announcement of its discovery in the atmosphere of Mars in 2003, methane has “punched above its weight” of a mere few parts per billion in our scientific imagination of the red planet. This fascination is the result of two factors. First, methane has a lifetime of only a few centuries in the Martian atmosphere, which implies that any methane observed must be resupplied in the present day. Secondly, on the Earth, atmospheric methane is produced mostly through biological processes. This has prompted cautious excitement surrounding the idea that a martian biology working deep underground could be providing the needed methane. The reality is more complex with numerous sources and sinks of methane in the martian environment, most of which are abiotic. In this talk, I will present a history of the investigation of martian methane and discuss some of my own work on this topic before looking to our future hopes of unraveling the story of this mysterious gas.

Host: J.J.

Location: MP1318

Location: MP1318A

The schedule of speakers: https://tinyurl.com/cita-blackboard Location: MP 1318A

Location: MP 15th Floor Conf Room

Title: Into the starlight: Learning the Milky Way

Abstract: Understanding physical processes responsible for the formation and evolution of galaxies like the Milky Way is a fundamental but unsolved problem in astrophysics. Most stars are long-lived, using the stars as "fossil records" (what is known as Galactic archaeology) can offer unparalleled insight into the assembly of galaxies. The landscape of Galactic archaeology is rapidly changing thanks to on-going large-scale surveys (astrometry, photometry, spectroscopy, and asteroseismology) which provide a few orders of magnitude more stars than before. I will discuss various "phenomenological" opportunities enabled by large surveys. I will also discuss how we could describe substructures in the Milky Way through the lens of deep learning.

Host: Katie

Location: MP1318

Weekly paper discussion focussing on pulsars, compact objects, and propagation effects.

For a list of upcoming discussions, see:
https://docs.google.com/spreadsheets/d/1KEyKBCmeGFUmMoiYKuHEDguCv9OOrEZqm3A6GM1Slk0/edit?usp=sharing 

If you would like to sign up for the presenter rota, email: simard@astro.utoronto.ca Location: CITA lounge

Open discussion of stars- and planets-related topics or more specialized discussion of dynamics-related papers on alternating weeks. See here for details. Location: MP 1318A

The schedule of speakers: https://tinyurl.com/cosmo-rota  
Location: 15th floor conference room

Location: MP1318A

The schedule of speakers: https://tinyurl.com/cita-blackboard Location: MP 1318A