INAOE | Astrofísica | Seminarios
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2017-01-20 Casting shadows on a fiery sky: obscuration events in active galactic nuclei
Investigador Invitado Jacobo Ebrero
Filiación Institucional ESAC, Madrid, Spain
Resumen: Ver resumen Active galactic nuclei (AGN) are characterised by their X-ray emission, which is known to vary at short and long timescales. While their variability can sometimes be due to intrinsic variations in the accretion flow, in other occasions it may attributed to the passage of intervening material across our line of sight. The monitoring of such obscuring or eclipsing events are of particular interest as they can be useful to probe the dynamics and physical properties of the matter in the vicinity of the central supermassive black hole.

These events have been reported as short eclipses, possibly due to the passing of broad line region clouds, as well as longer periods compatible with a long-lasting stream of material intersecting our line of sight. In fact, systematic studies of these kind of obscuration events show that they may be more common than previously thought, happening regularly in a majority of AGN, but they have passed unnoticed due to the lack of continuous monitoring.
Lugar-Hora - 12:00
2017-01-25 Is there really such a thing as Dark Matter?
Investigador Invitado Xavier Hernandez
Filiación Institucional IA-UNAM
Resumen: Ver resumen I will review a number of scalings and astronomical observations which suggest that
the gravitational anomalies usually ascribed to the presence of an as yet undetected and
hypothetically dominant dark matter, might instead signal a change in the character of
gravity in the low acceleration regime. Such ideas lead to testable predictions in a number
of low acceleration astronomical systems, which I will describe. Spanning over 11 orders of
magnitude in mass, from wide binary stellar systems, through globular clusters, elliptical
and spiral galaxies, observations consistently suggest a change in gravity associated to
the local acceleration scale.
Lugar-Hora - 12:00
2017-01-26 Resolving Debris Discs with ALMA
Investigador Invitado Mark Booth
Filiación Institucional AIU, Jena, Alemania
Resumen: Ver resumen Debris discs were first detected 3 decades ago when it was noticed that IRAS observations of a number of stars showed an infra-red excess above the stellar photosphere. These observations were quickly followed-up by a resolved image of the dust around beta Pictoris, clearly demonstrating it to be an edge on disc. But few other discs were resolved until much more recently. Resolved images allow us to determine the radial distribution of dust in the disc. By looking for signatures in these resolved images they can tell us about the dynamical history of the planetary system and where planets might orbit today. Much work along these lines has been done in the optical and infrared, but these observations are dominated by small grains that are affected by transport forces whereas sub-mm and mm observations have the benefit of being most sensitive to larger grains that trace the 'birth-ring' of planetesimals that are more useful for constraining dynamical effects of planets. ALMA has revolutionised such observations by giving us both high resolution and high sensitivity at long wavelengths. I will demonstrate its benefits by focusing on observations of two systems: HR 8799 and epsilon Eridani. HR 8799 is a massive A star and the only system so far where multiple planets have been directly imaged. Our observations allow us to see the inner edge of the disc for the first time. By comparing this with the expectations from dynamical simulations we find that either the planets orbits have changed during the evolution of the system or there must be an extra planet in the system beyond those so far detected. Epsilon Eridani is the nearest star to us known to have a debris discs at just 3.2pc away - this results in the disc being too large to fit within the ALMA primary beam. Because of this we focus our observations on the northern part of the disc. With our high resolution we are able to resolve the width of this disc, finding it to be one of the narrowest detected with a fractional width comparable to the Solar System. This suggests the possibility of a planet interior to the disc shaping the inner and outer edges as Neptune is thought to do to our own Kuiper belt.
Lugar-Hora - 12:00
2017-02-17 FILEC
Area: Inaoe
Investigador Invitado FILEC
Filiación Institucional INAOE
Resumen: Ver resumen tbd
Lugar-Hora - 12:00
2017-02-24 Connecting simulations and observations in galaxy formation studies
Investigador Invitado Giovanni Guidi
Filiación Institucional Leibniz Institute for Astrophysics Potsdam
Resumen: Ver resumen Observational and computational extragalactic astrophysics are two fields of research that study the same subject from different perspectives. However, as these two approaches are intrinsically different in their methodology, the connection between simulations
and observations is still not fully established.

In this talk I will discuss the possibility to combine both approaches in the study of galaxy formation and evolution, using the methods and results of one field to test and validate the methods and results of the other. I will present a study of the biases and systematics in the derivation of the galaxy properties in observations, using simulated galaxies' SEDs to test observational analysis algorithms, and I will show a
comparison between simulations and SDSS data. I will also discuss the creation of synthetic datasets that mimic the new generation of IFS survey, which can be used to test the accuracy of the observational analysis algorithms in recovering the spatially-resolved properties of galaxies.
Lugar-Hora Auditorio de Docencia - 12:00
2017-03-10 La masa y el espín de un agujero negro de Kerr a partir de observaciones
Area: FIsica
Investigador Invitado Alfredo Herrera Aguilar
Filiación Institucional IF-BUAP
Resumen: Ver resumen En esta charla se mostrará cómo se pueden calcular la masa y el espín
de un agujero negro rotatorio en el marco de la Relatividad General a
partir de observaciones, a saber, del corrimiento hacia el rojo/azul
que experimentan los fotones que son emitidos por las estrellas/gas
que orbitan en torno al agujero negro. Este simple método se puede
aplica al hipotético agujero negro central de nuestra galaxia.
Lugar-Hora - 12:00
2017-03-17 El azufre como trazador de abundancias químicas en galaxias con líneas de emisión
Investigador Invitado Angeles Diaz
Filiación Institucional
Resumen: Ver resumen Se discuten las ventajas e inconvenientes de usar el azufre como trazador de
la metalicidad del gas en nebulosas ionizadas y se presentan diferentes
aplicaciones a objetos con baja y alta metalicidad, gradientes de abundancias
y determinaciones de helio primordial.
Lugar-Hora Auditorio de Docencia - 12:00
2017-03-23 New 2-mm (Band-4) Receiver ("B4R") for LMT
Investigador Invitado Bunyo Hatsukade & Ryohei Kawabe
Filiación Institucional National Astronomical Observatory of Japan Chile Observatory & The University of Tokyo
Resumen: Ver resumen We are developing a single-beam and dual-polarization 2-mm-band
receiver system ("B4R") for LMT. The development of the receiver
is based on the ALMA band-4 receiver. In this talk we introduce the
B4R receiver and show the current status, future plans, and science
cases to be conducted with B4R/LMT.
We also present our ALMA observations of submillimeter galaxies
obtained by AzTEC/ASTE surveys.
Lugar-Hora - 15:30
2017-03-24 NEFER & FABCAM: A high order scanning Fabry-Perot and a monolythic detector for GTC
Investigador Invitado Margarita Rosado Solis
Filiación Institucional IA-UNAM
Resumen: Ver resumen NEFER (Nuevo Espectrómetro Fabry-Perot de Extrema Resolución) is a high spectral resolution, scanning Fabry-Perot Spectrometer. It will be installed in the OSIRIS instrument at the GTC 10 m telescope. This 3D instrument uses a high order scanning Fabry-Perot to obtain highly accurate kinematical information of extended cosmic sources such as galaxies or nebulae. Astronomical data obtained with this instrument lead to 3D spectroscopic data cubes composed of several images, each one at different gaps of the scanning Fabry-Perot Interferometer. In this talk we present a general description of the different phases of development and several astronomical applications on kinematical studies of extended sources.
Lugar-Hora - 12:00
2017-04-07 An empirical method to determine the resolved stellar population ages
Investigador Invitado Hector Ibarra
Filiación Institucional IA-UNAM
Resumen: Ver resumen One of the main hot topics in astrophysics is the study of how galaxies evolve. One of the points is the estimation of the stellar population ages; Multiple methods found in the literature depends on spectroscopic measurements to determine how old the stellar population are. In this study, we show that the stellar population ages depend strongly on their spatially resolved colours and their total Ha equivalent width. Therefore, we propose a single method using only photometric data to determine in an accurate way the ages of the resolved stellar populations. In this work, we use the MaNGA survey to analyse the local stellar population ages from a sample of 2,500 galaxies and 5 galaxies observed with the direct camera in the Guillermo Haro Observatory. This work is part of a collaboration with Javier Casado from the Universidad Autónoma de Madrid.
Lugar-Hora - 12:00
2017-04-14 EASTER
Area: Festividad
Investigador Invitado EASTER
Filiación Institucional INAOE
Resumen: Ver resumen tbd
Lugar-Hora - 00:07

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05-07-2010 a las 14:08 por Webmaster

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