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

   
2019-01-18 Fermi LAT observations of Sagittarius A* and nearby galactic nuclei
Area: Astrofísica
Investigador Invitado Rodrigo Nemmen
Filiación Institucional Universidade do Porto
Resumen: Ver resumen The nearest supermassive black hole—Sagittarius A* (Sgr A*), located at the center of the Milky Way—is a great laboratory to investigate the physical processes occurring in the vicinity of event horizons. I will present an ongoing analysis of ~10 years of Fermi LAT data (100 MeV - 300 GeV) of the point source likely associated with Sgr A*. I will also present Fermi LAT observations of a complete sample of nearby, low-luminosity active galactic nuclei. These observations are uniquely helping us to understand high-energy processes in nearby galactic nuclei.
   
Lugar-Hora Auditorio del Centro de Información - 12:00
   
2019-02-15 Inefficient jet-induced star formation in Centaurus A
Area: Astrofísica
Investigador Invitado Quentin Salome
Filiación Institucional IRYA-Morelia
Resumen: Ver resumen Star formation is one of the key mechanisms driving the evolution of galaxies across cosmic times. The environment certainly plays a role in star formation, therefore looking at large scales is essential to understand the physics of star formation. In particular, recent studies suggest that AGN can regulate the gas accretion and thus slow down star formation (negative feedback). However, evidence of AGN positive feedback is also invoked in a few radio galaxies.

The northern filaments of Centaurus A are a testbed region for positive feedback, here through jet-induced star formation. These filaments extend on scales up to 15 kpc, aligned with the radio-jet, and show evidence of recent star formation (Rejkuba et al. 2001). I will present different studies of the northern filaments of Centaurus A at different resolutions. Along the radio jet, at the intersection of the radio jet and a HI shell (Schiminovich et al. 1994), CO emission has been detected with SEST in the shell (Charmandaris et al. 2000).

We detected CO in a much larger area along the filaments with APEX (Salomé Q et al. 2016a) and ALMA (Salomé Q. et al. 2017), including outside the HI gas. The ALMA resolution (~20 pc) enabled us to separate giant molecular clouds and study their physical properties (mass, size, velocity dispersion).
   
Lugar-Hora Auditorio del Centro de Información - 12:00
   
2019-02-22 Quasars: from the physics of line formation to cosmology
Area: Astrofísica
Investigador Invitado Paola Marziani
Filiación Institucional INAF-Osservatorio Astrofisico di Arcetri
Resumen: Ver resumen Quasars accreting matter at very high rates (known as extreme
Population A (xA) or super-Eddington accreting massive black holes)
provide a new class of distance indicators covering cosmic epochs from
the present-day Universe up to less than 1 Gyr from the Big Bang. The
very high accretion rate makes it possible that massive black holes
hosted in xA quasars radiate at a stable, extreme luminosity-to-mass
ratio. This in turn translates into stable physical and dynamical
conditions of the mildly ionized gas in the quasar low-ionization line
emitting region. In this talk, I first analyze the systematization of
the main optical and UV spectral properties of quasars along their
“main sequence” and then introduce and discuss extreme Population A
quasars, with a focus on the physical conditions that are derived for
the formation of their emission lines and the selection criteria that
make them easily identifiable in large spectroscopic surveys over a
broad redshift range. Ultimately, the analysis supports the
possibility of identifying a virial broadening estimator from
low-ionization line widths, and the conceptual validity of
redshift-independent luminosities based on virial broadening for a
known luminosity-to-mass ratio.
   
Lugar-Hora Auditorio del Centro de Información - 12:00
   
2019-02-28 NGC6334I - Tracing the Gas Motion During A Contemporaneous Maser Flare
Area: Astrofísica
Investigador Invitado James Chibueze
Filiación Institucional North West University, SA
Resumen: Ver resumen NGC6334I showed evidence of episodic accretion event observed as flare in multiple maser species (water, methanol and hydroxyl) and a brightening of the dust continuum emission in millimeter wavelength.
Our multi-epoch water maser
observations overlapped with this episodic event. Evidence of compact outflows and turbulent gas motion can me seen in the region. MM1 (a dominant millimeter source in the region) recently excited 6.7 GHz methanol masers, and these gas motion we see around it trace the earliest activities associated formation of the driving source in the region.
   
Lugar-Hora Auditorio del Centro de Información - 15:00
   
2019-03-08 La evolución de los vientos nucleares en el AGN IRAS 17020+4544
Area: Astrofísica
Investigador Invitado Mario Sanfrutos
Filiación Institucional Instituto de Astronomía, UNAM
Resumen: Ver resumen La galaxia Seyfert 1 de líneas estrechas IRAS 17020+4544 presenta un complejo sistema de vientos nucleares formado por múltiples componentes a velocidades tanto relativistas como lentas (Ultra-Fast Outflows o UFOs y Warm Absorbers o WAs, respectivamente). En esta plática presentaré el análisis de los espectros de difracción tomados con XMM-Newton en 2004 y 2014, en donde encontramos que el WA está formado por varias capas de gas ionizado, algunas de las cuales presentan una peculiar evolución a lo largo de los 10 años transcurridos entre las observaciones: hallamos componentes cuasi estacionarias junto a otras en inflow y en outflow, con variaciones significativas de sus velocidades. Nuestra interpretación de estos resultados se enmarca en la hipótesis del "shocked outflow", según la cual esta evolución sería el resultado de las turbulencias inducidas en el viento al chocar con el gas circunnuclear.
   
Lugar-Hora Auditorio del Centro de Información - 12:00
   
2019-03-15 Luz en la expansión acelerada del universo (Fin de la era obscura)
Area: Cosmología
Investigador Invitado Carlos Ortiz
Filiación Institucional Universidad Autónoma de Zacatecas
Resumen: Ver resumen Mediante la variación de la acción de Hilbert - Einstein y utilizando las leyes de termodinámica se llega a explicar la expansión acelerada del universo; lo anterior sin necesidad de introducir a mano la constante cosmológica, dimensiones extra o hacer modificaciones a las ecuaciones de campo de la Relatividad General, i.e. sin cucharear. El modelo también resuelve otros problemas de la cosmología, como son el problema de coincidencia de la constante cosmológica.
   
Lugar-Hora Auditorio del Centro de Información - 12:00
   
2019-03-29 Restarting activity in the nuclei of Giant Radio Galaxies
Area: Astrofísica
Investigador Invitado Lorena Hernández
Filiación Institucional Universidad de Valparaiso
Resumen: Ver resumen Giant radio galaxies (GRG) are defined as those active galactic nuclei (AGN) whose radio morphology show linear extended emission above 0.7 Mpc. The lobes in these galaxies can be as old as 10^8 years, whereas the AGN activity can be reactivated within 10^4-8 yrs, thus GRG are perfect laboratories to study AGN evolution and restarted activity. The usual way to find restarting activity is through the radio morphology, where different phases of nuclear activity can be observed in the same dataset. However, we might be missing a fraction of restarting activity in galaxies because we are not able to detect the earliest phase where the new jets have recently formed and are not visible in the radio band. In this seminar I will focus on two cases of restarted activity on early phases, namely PBC J2333.9-2343 and Mark 1498. These sources were selected on a hard X-ray basis and we performed multiwavelength analyses in order to gain information of different emitting regions and to have the most comprehensive view of their nuclei.
   
Lugar-Hora Auditorio del Centro de Información - 12:00
   
2019-04-05 Multi-wavelength variability of the blazars 3C 279 and 3C 273 and its relation with the pc-scale jet
Area: Astrofísica
Investigador Invitado Victor Manuel Patiño Álvarez
Filiación Institucional INAOE
Resumen: Ver resumen En esta charla, presento los resultados de la investigación hecha a las fuentes 3C 279 y 3C 273.
Usamos curvas de luz multifrecuencia que abarcan más de 6 años, desde radio hasta rayos gamma,
con el objetivo de descifrar la estratificación de las diferentes regiones de emisión, así como los mecanismos
de emisión dominantes. Además, presento la localización exitosa de una región de emisión de rayos gamma
en el blazar 3C 279. También daré una corta explicación acerca de cómo malinterpretar resultados estadísticos
pueden llevar a conclusiones erróneas en este tipo de estudios.
   
Lugar-Hora Auditorio del Centro de Información - 12:00


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