Letters of Intent for 2015

LoI 2015-207
Focus Meeting: The synergy between massive stellar explosions and their hosts

Date: 3 August 2015 to 5 August 2015
Location: IAU GA Hawaii 2015, United States
Contact: Christina Thoene (cthoene@iaa.es)
Coordinating division: Division J Galaxies and Cosmology
Co-Chairs of SOC: Christina Thöne (IAA - CSIC, Granada)
Lise Christensen (Dark Cosmology Centre, NBI, Copenhagen)
Chair of LOC: --- (---)



- Host galaxies of GRBs, SNe and massive stars
- Starburst galaxies as potential host of massive stellar explosions
- Diversity of GRBs, SNe and their progenitors
- Dependence of stellar evolution on the properties of their progenitors and environments
- Resolved observations of the explosion environments
- Influence of stellar explosions on their environments
- Chemical evolution of galaxies due to massive stellar explosions
- Probing the first galaxies with GRBs
- Future facilities and techniques



The explosion of massive stars such as GRBs and SNe are among the most powerful and luminous events in the Universe. Their progenitors require special conditions to form and upon their explosive death they release energy and heavy elements back into their environment and a new cycle of star-formation begins with different initial conditions. Those stellar explosions also play an important role in the general evolution of galaxies across the entire history of the Universe. In this Focus Meeting we want to foster the interaction between the different communities working on massive stellar explosions and star-forming galaxies and galaxy evolution to improve the knowledge of the scientific community on their mutual influences.

GRBs have been detected frequently since the launch of the Swift satellite in 2004, but their progenitors still remain largely a mystery. Long GRBs likely originate from metal poor massive stars in young star-forming regions, conditions primarily found in dwarf galaxies in the local Universe, while short GRBs are the product of the coalescence of two compact stellar remnants and should be found in older populations, although exceptions from all of these conditions have been found. Outliers from both classes call for yet different progenitors and challenge theoretical modeling. Likewise SN classification has diversified in the last decade. In particular, new untargeted surveys like PTF or PanSTARRS allow to find completely new types such as superluminous supernovae that had gone undetected previously and that might occur only under particular conditions. Which kind of galaxies are capable to host the different kinds of explosions? How well are they represented by the different star-burst galaxy populations in the nearby universe? Are they any special in terms of star-formation history, their ability to form new stars, their chemical composition or their environment? Do we need large star-formation triggers to produce SF leading to those stellar explosions?

Spatially resolved observations of the environment of stellar explosions have only been started in recent years and could give some important clues on the composition of the progenitor star, especially when the progenitor cannot be detected. A crucial question to answer is, whether we will be able to conclusively relate the properties of the environment with the progenitor and which observations do we need for this. How different is the evolution of the progenitor under different initial conditions? Are there clear knock-out criteria for different progenitors and their end state? How different can the conditions be throughout a galaxy and what role does spatial resolution play in our conclusions? Large IFU surveys are currently ongoing (e.g. CALIFA) or in planning (e.g. MANGA and SAMI) together with a range of new large-scale facilities in the optical and IR like KMOS/MUSE at the VLT and NIRI/NIRSpec at JWST, making it possible to extend these studies to higher redshifts. Narrow-band tunable filters allow studies at imaging resolutions are available e.g. at GTC and planned in the IR for JWST.

Massive explosions surely do not leave their environments and host galaxies unaltered. Massive stellar explosions can both inhibit and give rise to new (massive) star formation in their surroundings and hosts. SNe and GRBs are responsible for the creation of a large part of heavy elements, released or first created during the explosion. This enriches the host galaxy with metals that will influence the composition of the next generation of stars or it can even leave the galaxy via galactic winds and deplete the intergalactic medium. How would a GRB remnant look like and are there any examples for them in the local Universe? To which degree do stellar explosions influence the star-formation in their surroundings and in their hosts in general? What is their role in the feedback of energy and metals into the IGM? How do they influence the formation of new massive stars and their properties? Which influence do they have on the evolution of their hosts in general?

Last but not least, stellar explosions, in particular GRBs, allow us to trace SF across the entire history of the universe out to the very first galaxies. Which role do galaxies hosting stellar explosions play in the general star-formation history of the Universe? How well do they trace global star-formation? How have the conditions in star-forming galaxies changed over time?

In this meeting we want to bring together observers and theorists from both the GRB/SN and the starburst galaxy communities. We want to approach the link between massive stellar explosions and their hosts using different wavelengths and observing techniques and relate them to state of the art stellar evolution and stellar population modeling. The following people have already agreed to be part of the SOC: S. Vergani (IAP, France), M. Modjaz (NYU, USA), K. Maeda (Kyoto Univ., Japan), K. Belczynski (Warsaw Univ., Poland), N. Tanvir (Univ. Leicester, UK), L. Kewley (ANU, Australia), J. Prochaska (UC Santa Cruz, USA), F. Matteucci (Univ. of Trieste, Italy), A. Gal-Yam (Weizmann Inst., Israel) and G. Östlin (OKC, Sweden)