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.


July 2015

1.07.15 (Wednesday)
12:00
"Unveiling a Mysterious World - Dawn arrives at Ceres"
Jian-Yang LI (Planetary Science Institute)
Abstract
Close
"Unveiling a Mysterious World - Dawn arrives at Ceres"

Jian-Yang LI (Planetary Science Institute)

Abstract

Dawn spacecraft entered the first science orbit around Ceres in late April 2015, starting its year-long mapping activity of this mysterious world. Ceres, as the largest object located near the water ice-line in the current solar system, could hide clues about water transportation shaping the habitable Earth, as well as the process of the formation of outer solar system planets and icy satellites. It may also holds secrets of the new category of objects in the asteroid belt that are actively outgassing, the so-called Main-Belt Comets. However, little is known about Ceres after more than 200 years since its discovery, due primarily to its nearly featureless visible-infrared spectrum and lack of meteorite analogues. Since approach, Dawn spacecraft has collected images of Ceres with resolutions down to 400 m/pixel so far. Many spectacular features on the surface have been identified, such as bright spots, large scale lineaments, relaxed basins, and mysterious mons, all much more interesting than one could ever expect. The study of Ceres is just beginning. I will briefly introduce the background of Ceres, and discuss some early images of interesting surface features.

7.07.15 (Tuesday)
12:00
"Massive-star magnetospheres in the NIR"
Mary OKSALA (LESIA, Observatoire de Paris)
Abstract
Close
"Massive-star magnetospheres in the NIR"

Mary OKSALA (LESIA, Observatoire de Paris)

Abstract

Magnetospheres of massive stars are known to exhibit variable emission signatures in the Hydrogen recombination lines in spectroscopy in optical wavelengths (i.e. the Balmer series). These features have been used to study both the mass content and the structure of the magnetosphere. This work aims to broaden our knowledge of these circumstellar environments into the near-infrared. We explore the line profiles produced in the Brackett series as a possible magnetic diagnostic, examining their shapes and variability. Infrared is fast becoming the next frontier, and this study represents a first step in utilizing the benefits of longer wavelengths over UV and optical.

14.07.15 (Tuesday)
12:00
"Spurious and real iron spreads in globular clusters"
Alessio MUCCIARELLI (Universita' degli Studi di Bologna, Italy)
Abstract
Close
"Spurious and real iron spreads in globular clusters"

Alessio MUCCIARELLI (Universita' degli Studi di Bologna, Italy)

Abstract

For several decades, globular clusters have been considered the best example of simple stellar populations, hosting coeval and chemical homogeneous stars. In particular, the striking homogeneity in terms of iron abundance is usually considered as the main chemical signature of globular clusters. In the last years, deep and extensive spectroscopic investigations have revealed a more complex picture, with the discovery of some massive clusters harboring intrinsic iron spread (like the extreme cases of Omega Centauri and Terzan 5). In this talk I will review the main evidence collected so far for "anomalous" clusters with intrisic iron spreads and I will discuss some effects able to mimic spurious metallicity spreads in some "peculiar" globular clusters like NGC3201 and M22.

16.07.15 (Thursday)
12:00
"Understanding the z~6 Quasars Population: New Insights from Pan-STARRS1"
Emanuele Paolo FARINA (Max-Planck-Institut für Astronomie)
Abstract
Close
"Understanding the z~6 Quasars Population: New Insights from Pan-STARRS1"

Emanuele Paolo FARINA (Max-Planck-Institut für Astronomie)

Abstract

Luminous quasars at high redshift provide direct probes of the evolution of supermassive black holes (SMBH) and the intergalactic medium (IGM) at early cosmic time. Over the last decade, numerous studies have established a sample of ~60 luminous quasars at z>5.5, selected using data from the Sloan Digital Sky Survey (SDSS) and the CFHT Quasar Survey. These studies have established the existence of SMBHs less than a Gyr after the Big Bang, and the presence of almost complete Gunn-Peterson absorption, indicating the end of the reionization at z~6. The discovery and characterisation of a statistically significant sample of bright quasars in this redshift range is crucial to further study this important era in the history of the Universe. The unprecedented sky coverage and depth of the Pan-STARRS1 (PS1) survey represents a fundamental step forward in building a complete sample of high-z quasar, and allowed us to more than double the number of z~6 quasars known in less then 3 years. Our new sample include quasars that are nearly a magnitude fainter that the SDSS ones and shows a variety of quasars properties, in terms of both luminosities and spectral features. During the talk I will present new results from our search for high redshift quasars and our effort to understand the environment where supermassive black holes can form in the early Universe.


June 2015

30.06.15 (Tuesday)
12:00
"The circumstellar environment of evolved stars at high angular resolution"
Miguel MONTARGES (IRAM, Grenoble)
Abstract
Close
"The circumstellar environment of evolved stars at high angular resolution"

Miguel MONTARGES (IRAM, Grenoble)

Abstract

Chemical enrichment of the Galaxy, and ultimately of the Universe is caused by evolved stars. Nuclear fusion is producing heavy elements in their interior which are moved to the surface thanks to large convective motions. Pulsating models of AGB stars can correctly explain how the evolved material is expelled from the photosphere to the circumstellar environment, and how dust condensates. However, it cannot account for the bipolar structure of many planetary nebulae. We manage to directly image the dust scattering by a disk around the close AGB star L2 Puppis with VLT/NACO and of its stellar companion with VLT/SPHERE. This will help understanding the shaping of planetary nebulae of the hourglass type. On the massive star side, no scenario account for the the triggering of the mass loss of red supergiant stars (RSG) as they are not experiencing pulses nor flares. I will review our recent observations of the close environment of the nearest RSG star, Betelgeuse.


Future Talks

Choose your preferred calendar format to stay informed