Astrofísica

In this contribution, I will discuss my work in creating synthetic spectra for specific time-steps along the formation of a protostellar core considering different initial conditions. Synthetic spectra are created for optically thick molecular transitions such as HCO+ J=1-0 and NH3 (1,1) due to their moderate critical densities (relative to typical molecular cloud volume densities), which allows the detection of such transitions far from the perceived core centre. In the case of NH3 (1,1), we have included the underlying magnetic hyperfine structure components so that we are able to test the hypotheis presented by Pineda et al. (2010) termed the "transition to coherence" whereby the intrinsic hyperfine components begin to emerge once the turbulent motions of the core gas subside close to the core centre with the inward motions becoming more coherent. I will also discuss the theory underpinning a spectral data analysis routine called COLHYPOD to which I am contributing to.

We present the study of the evolution of the star formation and the nuclear acitivity in compact groups of galaxies over the past 3 Gyr. Our analysis is based on the largest multi-wavelength compact group sample to-date, containing complete UV-to-IR photometry for 1,770 groups (7,417 galaxies). We classify the nuclear activity of the galaxies based on optical emission line and mid-IR diagnostic classifications and estimate the physical properties of the galaxies using theoretical spectral energy distribution modeling. Concering the nuclear activities, we observe a singificant increase of the number of the AGN-hosting galaxies as we are moving towards lower redshifts, and we report the almost complete absence of Seyfert 1 nuclei. On the other hand, we observe a singificant "reddening" of the UV-optical colours of the galaxies and a decrease of their specific star formation rates, caused by both the reduction of their star formation rates as well as the build-up of their stellar masses, over the past 3 Gyr. Our results suggest that the depletion of gas, due to past star formation and/or tidal stripping is the major mechanism driving the evolution of the star formation and nuclear activity in compact groups.

El Servicio de Clima Espacial - MX [SCIESMEX] es uno de los servicios que brinda la Universidad Nacional Autónoma de México (UNAM) para coordinar el intercambio de información entre las redes internacionales de Clima Espacial (ISES) y el público en general. A su vez, parte de nuestros objetivos se centran en distribuir los productos y servicios regionales de Clima Espacial a la comunidad internacional, recopilar información en tiempo real sobre las condiciones en el Sol, viento solar, magnetosfera, ionosfera y termosfera que pueden afectar la operación y confiabilidad de sistemas tecnológicos en tierra y aire que pueden poner en peligro la salud o vida humana en nuestro país.

We used the L(Hbeta) -sigma distance estimator based on the correlation between the ionised gas velocity dispersion and Balmer emission line luminosities of HII Galaxies and Giant H II regions to trace the expansion of the Universe up to z - 2.33. This approach provides an independent constraint on the equation of state of dark energy and its possible evolution with cosmic time. We have used Very Large Telescope and Subaru high-dispersion spectroscopic observations of a local sample of H II galaxies, identified in the Sloan Digital Sky Survey Data Release 7 (SDSS DR7) catalogue in order to redefine and improve the L(Hbeta) - sigma distance indicator and to determine the Hubble constant. To this end, we utilized as local calibration or 'anchor' of this correlation GEHR in nearby galaxies which have accurate distance measurements determined via primary indicators. Using our best sample of 69 nearby H II galaxies and 23 GEHR in nine galaxies, we obtain H0 = 74.3 +/- 3.1 (statistical) +/-2.9 (systematic)kms-1 Mpc-1. We present high-dispersion spectroscopy of HII galaxies at redshifts between 0.6 and 2.33, obtained at the VLT using XShooter. Using six of these HII galaxies we obtain broad constraints on the plane Omega_m - w0. The addition of 19 high-z HII galaxies from the literature improves the constraints and highlights the need for high quality emission line profiles, fluxes and reddening corrections. The 25 high-z HII galaxies plus our local compilation of 107 H II galaxies up to z = 0.16 were used to impose further constraints. Our results are consistent with recent studies, although weaker due to the as yet small sample and low quality of the literature data of high-z HII galaxies. We show that much better and competitive constraints can be obtained using a larger sample of high redshift HII galaxies with high quality data that can be easily obtained with present facilities like KMOS at the VLT.

tbd

Powerful relativistic jets in radio-loud active galactic nuclei (AGN) can deposit enormous amounts of mechanical energy into their surroundings, potentially regulating star-formation in the host galaxy and the fuel supply back onto the supermassive black hole. Substantial progress in our understanding of AGN jets has been made in recent times, particularly in relation to the conditions required for efficient jet formation, as well as our knowledge of the three-dimensional magnetic field structure of the jet. I will review our current understanding of AGN jets before presenting new radio polarization and Faraday rotation observations of radio-loud AGN from parsec to kiloparsec scales. I will show the importance of full-Stokes, broadband radio observations in providing important constraints on fundamental jet parameters such as the jet magnetic field strength, it's 3D structure, and the amount of magnetic flux at the jet launching site.

We have recently discovered that Holm 15A, the brightest cluster galaxy in Abell 85 (A85-BCG), could host an ultramassive black hole (UMBH) with a mass of about one hundred billion solar masses. This large black hole mass results from extrapolations of black hole mass scaling laws with host galaxy estructure and dynamics. We review known scaling laws and discuss the existence of UMBH in the universe. We also comment on the likely effects of UMBH on galaxy formation and evolution.

En esta plática muestro recientes resultados que parecen demostrar que existe una relación entre el fenómeno de altas discrepancias de abundancias en nebulosas planetarias (diferencias en las abundancias obtenidas a partir de líneas de excitación colisional y líneas de recombinación) y el hecho de que la estrella central sea un sistema binario de período muy corto que ha experimentado una fase de envoltura común. Se presentan resultados obtenidos a partir de espectrofotometría profunda con el telescopio de 4.2m WHT en el Roque de Los Muchachos, en La Palma de tres nebulosas planetarias: Abell 46, Abell 63 y Ou5. Se discutirá sobre el posible orígen de la discrepancia de abundancias en este tipo de objetos.

The launch of the Fermi satellite in 2008 has led to an explosion in our knowledge of gamma-ray pulsars above 100 MeV, with over 150 pulsars now detected in this energy range. Twenty-eight pulsars have been detected by the Fermi Large Area Telescope (LAT) above 10 GeV and 13 of these show pulsations at even higher energies (> 25 GeV). Meanwhile, ground-based Imaging Atomospheric Cherenkov Telescopes (IACTs: H.E.S.S., MAGIC, and VERITAS) have reported emission above 50 GeV from 2 pulsars (the Crab and Vela), with the latest results from MAGIC suggesting that the Crab pulsar emits pulsations above 1 TeV. I will discuss a search for high-energy emission LAT-detected gamma-ray pulsars using the latest Fermi LAT data and outline a project to use the recently-inaugurated HAWC observatory to carry out a survey of the very high energy (VHE, > 100 GeV) sky to search for pulsations from gamma-ray pulsars in the Northern Hemisphere.

tbd

The key project “Chemical HErschel Surveys of Star form- ing regions” (CHESS), takes full advantage of the new opportunity offered by Herschel/HIFI and explores in a systematic way the frequency range between 480 and 1902 GHz in several star-forming regions. The goal of the project is to provide the first ever spectral census of this frequency range in a selected sample of sources covering the principal parameters and aspects of the star-formation process: mass of the forming star, its evolutionary status, and the interaction with the surroundings. In this talk I will focus on the results of the interstellar shock L1157-B1, in particular the studies of molecular species such as CO, H2O, CS, N2H+, among others.

Actualmente el Gran Telescopio Milimétrico se encuentra operacional usando los llamados instrumentos de Primera Luz (cámara de continuo, AzTEC y espectrómetro, RSR) dando soporte a los programas de Ciencia Temprana. Sin embargo existe la necesidad de nueva instrumentación que explote las capacidades del GTM tales como, velocidad de mapeo, profundidad y cobertura espectral. En esta plática se mostrará el diseño conceptual de una cámara para observaciones a 2 mm, basada en detectores de inductancia cinética en un arreglo de 10x10 pixeles. Además se mostraran los avances que el grupo de instrumentación tiene en los sub-sistemas de criogénia, RF y diseño de detectores.