RESEARCH/ conferences organized The Earth seen 
from the Moon
by
the Apollo XVI
NASA mission,
in UV light.

Earth as seen from the Moon in the UV band

Last update: February 9th, 2016

Main research lines are associated with Ultraviolet Astronomy, Astrophysical Plasmas and Star Formation. These activities are coordinated through the Space Astronomy Research Group at UCM: AEGORA .

As principal investigator of the Spanish participation in the Russian led space mission World Space Observatory - Ultraviolet (WSO-UV) most of my activity is concentrated in the development of the the WSO-UV Science Operations and Science Center in the UCM campus. 

The WSO-UV is a multipurpose observatory consisting of a 1.7 m-aperture telescope and three instruments for high-resolution spectroscopy, long-slit low-resolution spectroscopy, and deep UV and optical imaging. The WSO-UV mission will last for five years with a planned extension of five years more. The foreseen launch date is 2021. The Spanish site of the project can be accessed here

The WSO-UV will provide observations of exceptional importance for the study of several astrophysical problems. The mission has six key scientific objectives:

  • The study of galaxy formation and the chemical evolution of the Universe, covering the last 80% of its lifetime (0< z < 2).
  • The measurement of the properties of diffuse matter in the Universe and its distribution in galactic haloes.
  • The formation and evolution of the Milky Way.
  • The role of discs in astronomical engines.
  • The chemical composition and properties of the atmospheres of giant extrasolar planets.
  • The study of astrochemical processes in UV irradiated environments


My two most recent research works are:
Variation of the ultraviolet extinction law across the Taurus-Auriga star-forming complex. A GALEX based study
Gómez de Castro, A.I.
, López-Santiago, J., López-Martínez, F., Sánchez, N., de Castro, E., Cornide, M.
The Taurus-Auriga molecular complex (TMC) is the main laboratory for the study of low-mass star formation. The density and properties of interstellar dust are expected to vary across the TMC. These variations trace important processes such as dust nucleation or the magnetic field coupling with the cloud. In this paper, we show how the combination of near ultraviolet (NUV) and infrared (IR) photometry can be used to derive the strength of the 2175 Ĺ bump and thus any enhancement in the abundance of small dust grains and polycyclic aromatic hydrocarbons in the dust grains size distribution. This technique is applied to the envelope of the TMC, mapped by the GALEXAll Sky Survey (AIS). Ultraviolet and IR photometric data have been retrieved from the GALEX-AIS and the 2MASS catalogues. NUV and K-band star counts have been used to identify the areas in the cloud envelope where the 2175 Ĺ bump is weaker than in the diffuse interstellar medium namely, the low column density extensions of L1495, L1498 and L1524 in Taurus, L1545, L1548, L1519, L1513 in Auriga and L1482-83 in the California region. This finding agrees with previous results on dust evolution derived from Spitzer data and suggests that dust grains begin to decouple from the environmental Galactic magnetic field already in the envelope.
Protoplanetary disk shadowing by gas infalling onto the young star AK Sco
Gómez de Castro, A.I., Loyd, R. O., France, K.  Sytov, A.Yu., Bisikalo, D.
Young solar-type stars grow through the accretion of material from the circumstellar disk during pre-main sequence (PMS) evolution. The ultraviolet radiation generated in this process plays a key role in the chemistry and evolution of young planetary disks. In particular, the hydrogen Lyman-alpha line (Lya) etches the disk surface by driving photoevaporative flows that control disk evolution. Using the Hubble Space Telescope, we have monitored the PMS binary star AK Sco during the periastron passage and have detected a drop of the H2 flux by up to 10%  lasting 5.9 hours. We show that the decrease of the H2 flux can be produced by the occultation of the stellar Lya photons by a gas stream in free fall from 3 R*. Given the high optical depth of the Lya line, a very low gas column density of NH > 5x1017 cm-s suffices to block the Lya radiation without producing noticeable effects in the rest of the spectral tracers.
 
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