Latest talks

List of all the talks in the archive, sorted by date.


evanthia_hatziminaoglou_180522s
Tuesday May 22, 2018
Dr. Evanthia Hatziminaoglou
ESO (ALMA ARC)

Abstract

I will present ALMA Compact Array (ACA) 870 micron data of 28 infrared-bright SDSS quasars at redshifts 2 – 4 with estimated star formation rates beyond 1000 solar masses per year, the largest such sample ever observed with ALMA. The majority of the sources have unique ACA counterparts down to 3" - 4"resolution within the SPIRE 250 micron beam, centred on the SDSS coordinates. With only a handful of clear cases of multiple sources within the SPIRE beam, these results are in tension with works on the multiplicity of SPIRE 250 micron sources and sub-millimetre galaxies. I will present an extensive comparison between these findings and other recent works and will discuss the implications in the scenario supporting major mergers as triggers of the brightest AGN.


Henri_MJ_Boffin_180517s
Thursday May 17, 2018
Dr. Henri M. J. Boffin
ESO, Garching

Abstract

Binarity and mass transfer appear to play a key role in the shaping and, most likely, in the formation of planetary nebulae (PNe), thereby explaining the large fraction of axisymmetric morphologies. I present the binary hypothesis for PNe and its current status. Recent discoveries have led to a dramatic increase in the number of post-common envelope binary central stars of PNe, thereby allowing us to envisage statistical studies. Moreover, these binary systems let us study in detail the mass transfer episodes before and after the common envelope, and I present the evidences for mass transfer - and accretion - prior to the common envelope phase.


iacopo_bartalucci_180510s
Thursday May 10, 2018
Dr. Iacopo Bartalucci
CEA, Université Paris-Saclay

Abstract

We present a detailed study of the spatially resolved thermodynamic and hydrostatic mass profiles of the five most massive clusters detected at z~1 via the Sunyaev-Zel'dovich effect. These objects represent an ideal laboratory to test our models in a mass regime where structure formation is driven mainly by gravity. We present a method to study these objects that optimally exploits information from XMM-Newton and Chandra observations. The combination of Chandra’s excellent spatial resolution and XMM-Newton’s photon collecting power allows us to spatially resolve the profiles from the core to the outskirts, for the first time in such objects.  Evolution properties are investigated by comparison with the REXCESS  local galaxy cluster sample. Finally, we discuss the current limitations of this method in the context of  joint analysis of future Chandra and XMM large programs and, more generally, of  multi-wavelength efforts to study high redshift objects.


Carles_Badenes_180503s
Thursday May 3, 2018
Dr. Carles Badenes
University of Pittsburgh / ICCUB

Abstract

I will discuss our present knowledge of the statistics of stellar multiplicity (the multiplicity fraction and the distribution of periods, mass ratios, and eccentricities), and the implications for stellar evolution, in particular for Type Ia Supernovae (SN Ia). I will describe how multi-epoch radial velocity measurements from large spectroscopic surveys can open a new observational window on stellar multiplicity, and present two case studies: white dwarfs in SDSS/SEGUE and the ESO SPY survey, and main sequence stars and red giants in SDSS/APOGEE. For the white dwarfs, we can measure their merger rate and evaluate their viability as Type Ia SN progenitors. For the main sequence stars and red giants, we can explore the interplay between stellar evolution and stellar multiplicity, evaluate the rate of stellar mergers, and uncover a strong dependence of the multiplicity fraction with metallicity.


javier_licandro_180412s
Thursday April 12, 2018
Dr. Javier Licandro
IAC

Abstract

The IAC Solar System group has been cooperating with NASA’s OSIRIS-REx mission since 2011 when I became member of its Science Team. In 2015 we came to an agreement to be members of the Image Processing Working Group (IPWG) to perform two main tasks: produce and analyze the Color-ratio Maps and participate in the in-flight calibration of the cameras (OCAMS). Actually 5 members of our group are participating in the science of the mission.

OSIRIS-REx was launched in 2016 and will visit the asteroid Bennu. It will completely characterize Bennu during 2018-2019, and took a sample of material from the surface that will bring to Earth for detailed study in 2023. Bennu is the primitive near-Earth asteroid more accessible and is also one of the Potentially Hazardous asteroids most likely to collide with Earth. It is well stablished that primitive class asteroids are the parents of carbonaceous chondrite meteorites, the meteorites with the most primitive known composition. Their primitive nature and their water and complex organics content make their study have a high cosmogonic and astrobiological interest

With the aim of supporting the science return of OSIRIS-REx and other two missions (JAXA’s Hayabusa II and ESA’s MarcoPolo-R), we started in 2010 our PRIMitive Asteroids Spectroscopic Survey (PRIMASS). As part of the PRIMASS project, we are obtaining visible and near infrared spectra of the members of the primitive collisional families and dynamical groups of the main asteroid belt. 

In this seminar I will present OSIRIS-REx mission and summarize the research activities of the IAC Solar System group, in particular those related with our participation in the OSIRIS-REx mission: (1) the preparation for the analysis of OCAMS images using Dawn images of Ceres; (2) the spectroscopic characterization of the inner main belt primitive asteroids families from which Bennu likely came from.


mike_beasley_nacho_trujillo_180322s
Thursday March 22, 2018
Dr. Mike Beasley, Dr. Ignacio Trujillo
IAC

Abstract

The discovery of relic galaxies in our nearby Universe allow us to explore the physical conditions that took place at the early stages of galaxy formation (z>2) with unprecedented detail. In this talk, we will describe how these objects have been found, what is the physical motivation to explore them and what are the most relevant results we have learnt so far. In particular, in this seminar, we will focus on our recent publication in the journal Nature, where we study the globular cluster population of the massive compact relic galaxy NGC1277 using the Hubble Space Telescope. The analysis of its globular cluster population has confirmed the extraordinary nature of this object. This galaxy underwent  an early collapse phase but failed to evolve and accrete smaller satellite galaxies. The study of the globular cluster of this system (which has no similar counterpart in the near Universe) gives unique insights into the formation and evolutionary processes of the most massive galaxies.


Enrica_Bellocchi_180320s
Tuesday March 20, 2018
Dr. Enrica Bellocchi
Centro de Astrobiología de Madrid

Abstract

The kinematic characterization of different galaxy populations is a key
observational input to distinguish between different galaxy evolutionary
scenarios, since it helps to determine the number ratio of rotating disks
to mergers at different cosmic epochs. Local luminous and ultra-luminous
infrared galaxies [(U)LIRGs] offer a unique opportunity to study at high
linear resolution and S/N extreme star forming events and compare them
with those observed at high z.
We obtained Very Large Telescope (VLT) VIMOS optical integral field
spectroscopy (IFS) data of a sample of 38 local (z < 0.1) (U)LIRGs (50
individual objects). Our goal is to analyze in detail the kinematics of
the
H\alpha ionized gas applying kinematic criteria able to characterize the
evolutionary status of these systems. In particular, the unweighted and
weighted kinemetry-based methods are used to kinematically classify our
galaxies in disk and merger. We also simulate our systems at z=3 to
evaluate how a loss of angular resolution affects our results.
From the kinemetry-based analysis we are able classify our local (U)LIRGs
in three distinct kinematic groups according to their total kinematic
asymmetry values (Ktot) as derived when using the weighted (unweighted)
method: 1) 25 out of 50 galaxies are kinematically classified as disk; 2)
out of 50 galaxies are kinematically classified as merger; 3) 16 out of 50
galaxies lie in the transition region, in which disks and mergers coexist.
When we apply our criteria to the high-z simulated systems, a lower total
kinematic asymmetry frontier value is derived with respect to that found
locally. The loss of angular resolution smears out the kinematic features,
thus making objects to appear more kinematically regular than actually they
are.


Begona_Vila_Costas_180314s
Wednesday March 14, 2018
Dr. Begoña Vila Costas
NASA/GSFC

Abstract

The James Webb Space Telescope is the largest, most complex telescope being launched to date. It includes segmented folded mirrors and a folded sunshield deploying on orbit and instruments with state of the art infrared detectors and different science capabilities operating below 45K (-228 C).
A rigorous test campaign including ambient and cryogenic tests to verify the health, performance and operations readiness in the conditions it will see on orbit is near its completion. We will talk about some of those tests and their challenges as all the observatory components get assembled, covering in particular the comprehensive program of thermal, optical, electrical and operational tests in the cryogenic chambers at Goddard Space Flight Center and Johnson Space Center. We will talk also about how the telescope achieves the pointing stability required for science operations by using the various components of its Fine Guidance System.


Hector_Socas_180308s
Thursday March 8, 2018
Dr. Hector Socas Navarro
IAC

Abstract

This paper puts forward a possible new indicator for the presence of moderately advanced civilizations on transiting exoplanets. The idea is to examine the region of space around a planet where potential geostationary or geosynchronous satellites would orbit (herafter, the Clarke exobelt). Civilizations with a high density of devices and/or space junk in that region, but otherwise similar to ours in terms of space technology (our working definition of “moderately advanced”), may leave a noticeable imprint on the light curve of the parent star. The main contribution to such signature comes from the exobelt edge, where its opacity is maximum due to geometrical projection. Numerical simulations have been conducted for a variety of possible scenarios. In some cases, a Clarke exobelt with a fraction alface-on opacity of ∼10^{-4} would be easily observable with existing instrumentation. Simulations of Clarke exobelts and natural rings are used to quantify how they can be distinguished by their light curve.

To appear in ApJ.


Olga_Zamora_180307s
Wednesday March 7, 2018
Dr. Olga Zamora, Juan José Sanabria y Francisco Javier Hernández
IAC

Abstract

En esta charla hablaremos sobre el proceso de actualización
del telescopio IAC80 en los últimos años, con el objetivo de llevar a cabo
observaciones muy exigentes en cuanto a número de imágenes, precisión temporal y astrométrica.
Se presentará la nueva cámara de gran campo CAMELOT-2
y su interfaz inteligente de usuario, que permite una observación cuasi-robótica por medio de macros
automáticas. Por último, se presentará el diseño del nuevo sistema de control, base de una futura robotización.



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