Abstract Aguilar-Ajello

[Alex Aguilar <alex.aguilar@jpl.nasa.gov>]

Please find attached my registration form and abstract for the upcoming
NASA Laboratory Astrophysics Workshop


Thank you,
Alex


Registration form
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Last name: Aguilar
First name: Alejandro
Middle name/initial:
Affiliation: Jet Propulsion Laboratory
Street Address: 
City:
Pasadena
State:
CA
Postal Code:
91109
Country: USA
Tel:
(818)354-0120
Fax:
(818)354-9476
E mail: alex.aguilar@jpl.nasa.gov
Citizenship*: Mexico
Abstract title: Visible to near infrared emission spectra of
electron-excited H$_2$
Special requirements:
*Non-US citizens should contact Cara Loomis if travel reimbursement for
the Workshop is required. 

\documentclass{article}
\begin{document}
\title{Visible to near infrared emission spectra of electron-excited
H$_2$}
\author{Alejandro Aguilar \and Geoffrey K. James  \and Herve Abgrall
\and Evelyne Roueff\and Joseph M. Ajello}
\date{24 January 2006}
\maketitle
\begin{abstract}

H$_2$ is the most abundant molecule in the universe and is an active
component of star formation.  Inside of dense molecular clouds,
heating and ionization occur by cosmic rays, X-rays and shock waves
generating energetic electrons. Collisional excitation by electrons
is the source of both UV and Visible-optical-IR (VOIR) H$_2$
fluorescence in the ISM, circumstellar disks and certain classes of
stars~[1]. Verification of the importance of collsional excitation
processes has occurred with analysis of HST and IUE observations of
Herbig-Haro (HH) Objects, T Tauri stars and reflection
nebulae~[2,3]. In particular, intense H$_2$ transitions in the VOIR
from various vibrational levels have been observed in
highly-collimated jets of matter from young stellar objects~[4].
These observed lines trace the colder molecular part of the
post-shocked gas~[5].

In recent work, we have demonstrated [6] that the gerade series
(EF$^1\Sigma^{+}_{g}$, GK$^1\Sigma^{+}_{g}$, H$^1\Sigma^{+}_{g}$,
I$^1\Pi_{g}$, J$^1\Delta_{g}$...) by virtue of its cascade spectrum
in the visible/near IR to the $n$~=~$2p\sigma$B and $2p\pi$C states,
the upper states of the Lyman and Werner bands, respectively, make a
significant contribution to the UV spectrum of H$_2$. Here, we have
measured the electron-impact-induced emission spectrum of H$_2$ in
the VOIR wavelength region of 700~nm to 950~nm at a spectral
resolution of 2~nm (FWHM). A model spectrum of H$_2$, based on newly
calculated transition probabilities and line positions including
rovibrational coupling for the strongest band systems is in
excellent agreement with observed intensities.

The VOIR emission spectra of H$_2$ and HD have never been studied
before in optically-thin single-scattering conditions. This work
will complete analytic models for use in electron transport codes of
the two most fundamental sets of electronic cross sections in UV
astronomy: the Lyman and Werner band systems
(B$^1\Sigma^{+}_{u}1s\sigma2p\sigma$ -- X$^1\Sigma^{+}_{u}$ and
C$^1\Pi^{+}_{u}1s\sigma2p\pi$ -- X$^1\Sigma^{+}_{u}$) of H2 and
HD~[7].
\end{abstract}

[1] Delgarno \textit{et al.}, Ap. J. Supp., \textbf{125}, 237,
(1999) [2] Herczeg \textit{et al.}, Astrophys. J., \textbf{607},
369, (2004) [3] Bergin \textit{et al.}, Astrophys. J., \textbf{614},
L133, (2004) [4] Nisini \textit{et al.}, A\&A, \textbf{441},
159-170, (2005) [5] Giannini \textit{et al.}, A\&A, \textbf{419},
999-1014, (2004) [6] Liu \textit{et al.}, Astrophys. J. Suppl.,
\textbf{138}, 229(2002) and J. Phys. B, \textbf{36}, 173(2003) [7]
Ajello \textit{et al.}, Astrophys. J. Supp., \textbf{159}, 314,
(2005).
\end{document}

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Alex Aguilar, Ph.D.
Research Associate
Jet Propulsion Laboratory 183-401
Earth & Space Science Division 320
Pasadena, CA 91109
Office: (818)354-0120
Lab: (818)354-3362
FAX: (818)354-9476

web-site: http://science.jpl.nasa.gov/people.cfm?PersonID=864

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