Seminars and Colloquia at ESO/Santiago

For ESO and ESO-related Conferences and Workshops in Europe and Chile please check the main Conferences and Workshops page.


Broadcast of the ESO talks is available upon request.  If anyone is interested, kindly contact us via email
at least 60 min prior  to the beginning of the talk.


May 2015

6.05.15 (Wednesday)
15:30
"Young brown dwarfs: testing star and planet formation"
Aleks SCHOLZ (University of St. Andrews, U.K.)
Abstract
Close
"Young brown dwarfs: testing star and planet formation"

Aleks SCHOLZ (University of St. Andrews, U.K.)

Abstract

Brown dwarfs - objects intermediate in mass between stars and planets - are ideal benchmark objects to test theories of star and planet formation. In particular, we hope to contribute to the understanding of the Initial Mass Function, the evolution of disks, and the physics of accretion. In this talk I will present results from a variety of observational studies focused on young brown dwarfs. I will show recent findings from our brown dwarf survey SONYC (Substellar Objects in Nearby Young Cluster), from IR and submm/mm observations of brown dwarf disks, and from variability studies aimed to constrain magnetic activity and accretion.

7.05.15 (Thursday) -- CANCELLED (to be re-scheduled soon!)
14:00
"The circumstellar environment of young brown dwarfs" (Joint ESO/ALMA Colloquium)
Jean-Louis MONIN (Obs. de Grenoble - Univ. J. Fourier, France)
Abstract
Close
"The circumstellar environment of young brown dwarfs"

Jean-Louis MONIN (Obs. de Grenoble - Univ. J. Fourier, France)

Abstract

Young brown dwarfs (BD) have intermediate masses between low mass stars and planets and therefore occupy a unique niche in our exploration of the star and planet formation process. Evidence are growing that stars and BD share the same formation mechanism (eg. Chabrier, 2013, PP6 conference). This common formation route could even be the same for free-floating planets. Among the physical phenomena related to star formation, accretion and ejection are ubiquitous. Young Brown dwarfs present a disk frequency similar and sometimes larger than the one of their higher mass TTS counterparts (eg. Monin et al. 2010). However, the outflow phenomenon remains quasi unexplored in the substellar domain. Using the IRAM 30m telescope, we have performed a systematic search for outflow signatures in a large sample of VLMS and BD in Taurus and ρ Oph star forming regions. In the course of this survey, we have confirmed previous detections (rho-OPH 102, MHO5 ; Phan-Bao 2008, 2011) and we have discovered 2 other outflows in BDs (FUTau, Monin et al. 2013 ; BD Tau 6, Monin et al. 2014, CS 18 conference).
I will also present follow-up observations on the IRAM interferometer that have revealed the structure of some of these outflows with a spatial resolution ~ 1 arcsec.

19.05.15 (Tuesday)
12:00
"Supernova environmental studies with Integral Field Spectroscopy"
Lluis GALBANY (Universidad de Chile)
Abstract
Close
"Supernova environmental studies with Integral Field Spectroscopy"

Lluis GALBANY (Universidad de Chile)

Abstract

Detecting the progenitor stars of different types of supernova (SN) directly would require a census of stars in nearby galaxies. Alternatively, the study of the environment once the supernova faded has proved to be succesful in constraining the properties of their progenitors. We used optical IFS of nearby SN host galaxies (0.005 < z < 0.03) provided by the Calar Alto Legacy Integral Field Area (CALIFA) Survey with the goal of finding correlations in the environmental parameters at the location of different SN types. The total sample consists of 128 SNe of all types in 113 galaxies. We focused on the properties related with star formation and the SN environmental metallicities, for which wide-field IFS enables proper comparisons of different approaches. In addition, we are also studying the coeval parent stellar populations of nearby SNe in finer details (~tens pc) with IFU spectrographs at several major telescopes including VLT, in order to directly derive SN progenitor physical properties. I will summarize the results from these two studies, and give prospects on the future of the IFS of SN environments.

22.05.15 (Friday)
12:00
"Searching for faint emission lines in very deep UVES spectra of photoionized nebulae"
Jorge GARCIA ROJAS ()
Abstract
Close
"Searching for faint emission lines in very deep UVES spectra of photoionized nebulae"

Jorge GARCIA ROJAS ()

Abstract

In this talk I summarize the results of more than 10 years of high-quality data obtained with UVES at VLT. We have detected very faint recombination lines (RLs) of C, O and Ne in Galactic and extragalactic H II regions that allow us to compute C, O and C/O radial gradients from RLs in the Milky Way and in other local group galaxies, such as NGC300. We have also determined C/O ratios from RLs in low-metallicity star-forming galaxies and I will discuss some of the implications of these results based on the comparison with chemical evolution models. I will also discuss the first results on an ambitious project aimed to the detection of extremely faint neutron-capture element emission lines in planetary nebulae to constrain the efficiency of the s-process and the convective dredge-up in the Asymptotic Giant Branch phase. Finally, I will make a picture of a new project devoted to accurate determinations of C/O ratios from RLs in double-dust chemistry (DC) Galactic planetary nebulae.


June 2015

3.06.15 (Wednesday)
12:00
"The massive stars nursery R136"
Zeinab KHORRAMI (Laboratoire Lagrange – Observatoire de la Cote d’Azur)
Abstract
Close
"The massive stars nursery R136 "

Zeinab KHORRAMI (Laboratoire Lagrange – Observatoire de la Cote d’Azur)

Abstract

As most stars are born in a clustered mode, young massive star clusters are the best places to find and study the formation and evolution of massive stars. R136 is one of the most massive nearby clusters in the LMC, which contains at least until now 72 known O and Wolf-Rayet stars. These young objects are usually embedded in dust and gas so that correcting the local extinction plays an important role for estimating the mass of stars. The extinction is derived for 26 O-stars in different HST filters using TLUSTY[3] atmosphere model for O-stars. Then we derived the mass and hence the Mass Function (MF) by multicolour photometry from HST data. We also simulated series of R136-like clusters using the Nbody6 code to test the segregation scenario for R136. thus we checked if massive stars tend to be formed locally at the center of a cloud or homogeniously. By comparing the surface brightness profiles (SBP) of simulated clusters mimicking R136’s SBP from HST data, we could determine which scenario is simulated the best R136. the results of these studies bring a new homogenious insight to the understanding of R136 and similar clusters in the light of future VLT and E-ELT high dynamic imaging observations at the diffraction limit in visible and IR wavelengths.

11.06.15 (Thursday)
12:00
"Unveiling the Massive Stars in the Galactic Centre"
Hui DONG (Instituto de Astrofísica de Andalucía, Spain)
Abstract
Close
"Unveiling the Massive Stars in the Galactic Centre"

Hui DONG (Instituto de Astrofísica de Andalucía, Spain)

Abstract

Because of the proximity, the Galactic Centre is a unique lab for studies of the interplay between stars, ISM and super massive black holes in galactic nuclei. The central 200 pc of the Galactic Centre includes 4x10^7 molecular clouds and has a star formation rate of ~0.03 M/yr. Three young, massive and compact star clusters were found and includes around 100 massive stars, which strongly shape the nearby ISM. However, the massive stars beyond the clusters are still unknown. A complete census of these `field' massive stars have an important impact on our understanding of several fundamental astrophysical questions, such as 1) how molecular clouds form stars in this extreme environments, 2) initial massive function and 3) the stellar evolution models for massive stars in high metallicity environment. I will present our effort during these years to identify massive stars in the Galactic Centre and study their properties and origin. Our results show that massive stars pervade the Galactic Centre and they partly formed in situ and partly were ejected from the three clusters.


Future Talks

Choose your preferred calendar format to stay informed