------------------------------------------------------------------------
 hvs.tex A&A, accepted
Date: Tue, 29 Jan 2008 13:01:46 +0100
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%http://www.sternwarte.uni-erlangen.de/~ai32/hvs.pdf
\documentclass{aa}
\usepackage{txfonts,graphicx}
\usepackage{natbib}
\bibpunct{(}{)}{;}{a}{}{,} % to follow the A&A style
\usepackage{epsfig}
\newcommand{\kms}{${\rm km \, s^{-1}}$}
\newcommand{\teff}{$T_{\rm eff}$}
\newcommand{\hei}{He {\sc i}}
\newcommand{\heii}{He {\sc ii}}
\newcommand{\nai}{Na {\sc i}}
\newcommand{\masy}{${\rm mas\,yr^{-1}}$}

\begin{document}

\title {{\sc\Large Letter to the Editor}\\[5mm]
LMC origin of the hyper-velocity star HE\,0437$-$5439\thanks{Based on
observations collected at the European Southern Obser\-vatory, Paranal, Chile
(DDT proposal 276.B-5024).}}
\subtitle{
Beyond the supermassive black hole paradigm}
%
\author {
N. Przybilla\inst{1} \and
M. F. Nieva\inst{1} \and
U. Heber\inst{1} \and
M. Firnstein\inst{1} \and
K. Butler\inst{2} \and
R. Napiwotzki\inst{3} \and
H. Edelmann\inst{1}}
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\offprints{przybilla@sternwarte.uni-erlangen.de}
%
\institute{Dr. Remeis-Sternwarte Bamberg, Sternwartstr. 7, D-96049 Bamberg,
Germany \and Universit\"atssternwarte M\"unchen, Scheinerstr. 1, D-81679
M\"unchen, Germany \and Centre for Astrophysics Research, University of 
Hertfordshire, College Lane, Hatfield AL10 9AB, UK
}
%
%
%
\date{Received... ; accepted ... }
%
\abstract
{Hyper-velocity stars move so fast that only a supermassive black hole (SMBH) 
seems to be capable to accelerate them. Hence the Galactic centre (GC) is 
their only suggested place of origin. Edelmann et al.~(2005) found the
early B-type star HE\,0437$-$5439 to be too short-lived to have reached its 
current position in the Galactic halo if ejected from the GC, except if being 
a blue straggler star. Its proximity to the Large Magellanic Cloud (LMC) 
suggested an origin from this galaxy.}
{The chemical signatures of stars at the GC are significantly different from 
those in the LMC. Hence, an accurate measurement of the abundance pattern of 
HE\,0437$-$5439 will yield a new tight constraint on the place of birth of 
this hyper-velocity star.}
{High-resolution spectra obtained with UVES on the VLT are analysed using 
state-of-the-art non-LTE modelling techniques.}
{We measured abundances of individual elements to very high accuracy in
HE\,0437$-$5439 as well as in two reference stars, from the LMC and the solar
neighbourhood, respectively. The abundance pattern is not consistent at all 
with that observed in stars near the GC, ruling our an origin from the GC.
However, there is a high degree of consistency with the LMC abundance pattern.
Our abundance results cannot rule out an origin in the outskirts of the
Galactic disk. However, we find the life time of HE\,0437$-$5439 to be more
than~three times shorter than the time of flight to the edge of the disk,
rendering a Galactic origin unlikely.}
{Only one SMBH is known to be present in Galaxy and none in the LMC.
Hence the exclusion of an GC origin challenges the SMBH paradigm. We conclude
that there must be other mechanism(s) to accelerate stars to hyper-velocity
speed than the SMBH. We draw attention to dynamical ejection from dense 
massive clusters, that has recently been proposed by Gvaramadze et 
al.~(2008).}
%
\keywords{Galaxy: halo -- Magellanic Clouds -- stars: abundances, distances,
early-type, individual (HE\,0437$-$5439)}
%
\titlerunning {LMC origin of the hyper-velocity star HE\,0437$-$5439}
\authorrunning {Przybilla et al.}
\maketitle
%
\end{document}