inaoe.edu.mx
INAOE | Astrofísica | Seminarios
Asignar puntaje:
 
Periodo Año:

   
2018-08-31 Extreme quasars at high redshift
Area:
Investigador Invitado Mary Loli Martinez Aldama
Filiación Institucional IAA-Granada, España
Resumen: Ver resumen The study of the AGN accreting close to the Eddington limit (L/LEdd~1) has taken an important role, due to their potential use as standard candles for cosmological applications. With the purpose to understand the physics of extreme quasar, we perform a spectroscopic analysis of a sample of highly accreting quasars at high redshift (z~2–3). Our sample were observed with the OSIRIS spectrograph on the GTC 10.4 m telescope located at the Observatorio del Roque de los Muchachos in La Palma. The highly accreting quasars were identified using the 4D Eigenvector 1 formalism, which is able to organize type 1 quasars over a broad range of redshift and luminosity. The kinematic and physical properties of the broad line region have been derived by fitting the profiles of strong UV emission lines such as AlIII λ1860, SiIII]λ1892 and CIII]λ1909. We find that AlIIIλ1860 can be associated with a low-ionization virialized sub-system. xA sources show strong blueshifts in the high-ionization lines like in CIVλ1549, indicating a relation between the high Eddington ratios and the productions of outflows. The extreme radiative properties of highly accreting quasar make them prime candidates for maximum feedback effects on the host galaxy. The characterization of extreme quasar allow to assemble large samples of extreme quasars from the latest data releases of the SDSS, especially useful for deriving independent estimates of ΩM in the redshift range 1<z<3.5.
   
Lugar-Hora - 12:00
   
2018-10-19 Masa y espín del agujero negro de Kerr en términos de corrimientos al rojo
Area:
Investigador Invitado Alfredo Herrera Aguilar
Filiación Institucional IF-BUAP
Resumen: Ver resumen En esta charla presentaremos fórmulas analíticas relativistas para estimar la masa y el espín de un agujero negro de Kerr en términos del corrimiento al rojo/azul de fotones emitidos por estrellas que lo orbitan siguiendo trayectorias circulares estables sobre el plano ecuatorial (o galáctico, de ser el caso), así como del radio orbital de dichas estrellas. En principio, estas fórmulas se pueden aplicar a ciertos sistemas astrofísicos
que poseen la estructura antes descrita si se tienen los instrumentos y la precisión necesarias. En el nivel de nuestras modestas aportaciones, la retroalimentación con los astrónomos es de crucial importancia.
   
Lugar-Hora - 12:00
   
2018-11-14 A submillimeter background galaxy projected on the debris disk of  HD95086 revealed by ALMA
Area:
Investigador Invitado Luis Alberto Zapata González
Filiación Institucional IRYA-Morelia
Resumen: Ver resumen In this talk, I present sensitive observations carried out with the  Atacama Large Millimeter/Submillimeter Array (ALMA) of the dusty debris disc HD 95086. These observations were made in bands 6 (223 GHz) and 7 (338 GHz) with an angular resolution of about 1’’, which allowed us to resolve well the bright debris disc. However, we did not detect CO (J = 2-1) and (J = 3-2) emission, excluding the possibility of an evolved gaseous primordial disc. From the mm. emission, we computed a dust mass for the debris disc HD95086 of 0.5 earth masses, resulting in a dust-to-gas ratio of more than 50, which is typical for debris. Our observations additionally detected a of a strong submillimeter source to the north-west of the disc. This new  object might be interpreted as a planet in formation on the periphery of the debris disc HD 95086 or as a strong impact between dwarf planets. However, given the absence of the proper motions of the object similar to those reported in the debris disc (estimated from these new ALMA observations) and for the optical star, this is more likely to be a submillimeter background galaxy. I will discuss the possibilities of finding more background galaxies in the ALMA fields.
   
Lugar-Hora - 16:00
   
2018-11-16 La Astronomía Mexicana bajo la luz de indicadores internacionales
Area:
Investigador Invitado J. Jesús González
Filiación Institucional
Resumen: Ver resumen La Astronomía se ha mantenido como la ciencia de mayor impacto y contribución internacional en nuestro país, algo sorprendente ya que México no ha participado proporcionalmente en los grandes consorcios e infraestructuras desarrolladas desde los años 90’s. Utilizando las herramientas de valoración científica, como el Word of Science, que utilizan las agencias y analistas internacionales en sus tomas de decisión,  presentamos un análisis de la producción e impacto de la Astrofísica Mexicana desde 1980. En este marco, al analizar también la astrofísica generada en UNAM, y en particular por el Instituto de Astronomía, estudiamos en mayor detalle puntos como segos en las citas y el factor de impacto como indicador de calidad. Finalmente, tocamos puntos relativos a la Revista Mexicana de Astronomía y Astrofísica.
   
Lugar-Hora - 13:00
   
2018-11-23 Comprehensive analysis of HD 105, a young Solar System analog
Area:
Investigador Invitado Jonathan Marshall
Filiación Institucional Institute of Astronomy and Astrophysics, Taipei
Resumen: Ver resumen HD 105 is a nearby, pre-main sequence G0 star hosting a moderately bright debris disc (Ldust/Lstar ∼ 2.6×10^-4). The star and its surroundings might therefore be considered an analogue of the young Solar System. We refine
the stellar parameters based on an improved Gaia parallax distance, identify it as a pre-main sequence star with an age of 50 ± 16 Myr. The circumstellar disc was marginally resolved by Herschel/PACS imaging at far-infrared wavelengths. Here we present an archival ALMA observation at 1.3 mm, revealing the extent
and orientation of the disc. We also present HST/NICMOS and VLT/SPHERE 
near-infrared images, where we recover the disc in scattered light at the ≥ 5-σ level. This was achieved by employing a novel annular averaging technique, and is the first time this has been achieved for a disc in scattered light. Simultaneous modelling of the available photometry, disc architecture, and detection in scattered light allow better determination of the disc's architecture, and dust grain minimum size, composition, and albedo. We measure the dust albedo to lie between 0.19 and 0.06, the lower value being consistent with Edgeworth-Kuiper belt objects.
   
Lugar-Hora - 15:00


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

Dirección: Luis Enrique Erro # 1, Tonantzintla, Puebla, México C.P. 72840 | Tel: (222) 266.31.00 Ext: 1324 y 1325 | Contacto: astrofi@inaoep.mx | Fax: 247.22.31

 

Esta obra está licenciada bajo una Licencia Creative Commons Atribución-No Comercial-Sin Obras Derivadas 2.5 México

Creative Commons License