On the nature of the microquasar V4641 Sagittarii
S. Chaty
We present photometric and spectroscopic optical and near-infrared (NIR) observations\footnote{Based on observations collected at the European Southern Observatory, Chile (ESO ID 63.H-0493 and 64.H-0382)} taken during the outburst of the recently flaring source V4641 Sgr = SAX J1819.3-2525 \citep{in'tzand:2000}, on September 1999. This source was independently detected as the {RXTE} source XTE J1819-254 \citep{markwardt:1999a}, and afterwards identified with the variable object V4641 Sgr \citep{kato:1999}. It underwent a bright optical outburst on 1999 Sept. 15.7 UT, going from magnitude 14 to 8.8 in the V-band \citep{stubbings:1999}, and reaching 12.2 Crab in the X-rays \citep{smith:1999} and $Ks \simeq 13$. This outburst was therefore bright, but very brief, with an e-fold decay time of 0.6 days. A radio source was resolved, making of V4641 Sgr a new microquasar \citep{hjellming:2000}. We discuss the nature of this system, showing that our observations suggest a distance farther than previously derived from the radio observations \citep{hjellming:2000}. The distance of the system would be between 3 and 8 kpc, the companion star being a B3-A2 main sequence star. Another possibility is that the companion star is crossing the Hertzsprung gap (type B3-A2 IV), and in this case the distance cited above would be the minimum distance of the system. The system is therefore an Intermediate or High Mass X-ray Binary System (IMXB or HMXB). The inconsistency regarding the distance between the radio and optical/NIR observations could be explained by the detection of an interaction between matter ejected before the X-ray outburst and the surrounding medium of the source. If this is confirmed, this source could be added to the short list of microquasars where such an interaction has been detected.
integral_sax.tex
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%% Copyright 1999 Patrick W Daly
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\title{On the nature of the microquasar V4641 Sagittarii}
\author{S. Chaty}
\affil{Department of Physics and Astronomy, The Open University, 
United Kingdom, s.chaty@open.ac.uk}
\author{I.F Mirabel}
\affil{Service d'Astrophysique, DSM/DAPNIA/SAp, Centre d'\'Etudes de Saclay, 
France}
\affil{Instituto de Astronom\'{\i}a y F\'{\i}sica del Espacio, Conicet, 
Argentina, mirabel@discovery.saclay.cea.fr}
\author{J. Mart\'{\i}}
\affil{Departamento de F\'{\i}sica, Escuela Polit\'ecnica Superior, 
	Universidad de Ja\'en, Spain, jmarti@ujaen.es}
\author{L.F. Rodr\'{\i}guez}
\affil{Instituto de Astronom\'{\i}a, Campus UNAM, Morelia, 
	Michoac\'an 58190, M\'exico, luisfr@astrosmo.unam.mx}

\newcommand{\btx}{\textsc{Bib}\TeX}
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\begin{document}

\keywords{stars: individual: V4641 Sgr, X-rays: stars, infrared: stars}

\maketitle

\begin{abstract}
We present photometric and spectroscopic optical and near-infrared (NIR)
observations\footnote{Based 
on observations collected at the 
European Southern Observatory, Chile (ESO ID 63.H-0493 and 64.H-0382)} 
taken during the outburst of the recently flaring source 
V4641 Sgr = SAX J1819.3-2525 \citep{in'tzand:2000}, 
on September 1999.
This source was independently detected as the {\it RXTE} source XTE J1819-254 
\citep{markwardt:1999a}, and afterwards identified with the
variable object V4641 Sgr \citep{kato:1999}.
It underwent a bright optical outburst
on 1999 Sept. 15.7 UT, going from magnitude 14
to 8.8 in the V-band  \citep{stubbings:1999}, 
and reaching 12.2 Crab in the X-rays
\citep{smith:1999} and $Ks \simeq 13$. 
This outburst was therefore bright, but very brief,
with an e-fold decay time of 0.6 days.
A radio source was resolved, making of V4641 Sgr a new microquasar 
\citep{hjellming:2000}.
We discuss the nature of this system, showing 
that our observations suggest a distance farther
than previously derived from the radio observations \citep{hjellming:2000}.
The distance of the system would be between 3 and 8 kpc, 
the companion star being a B3-A2 main sequence star. Another possibility
is that the companion star is crossing the Hertzsprung gap (type B3-A2 IV),
and in this case the distance cited above would be the minimum distance
of the system.
The system is therefore an Intermediate or 
High Mass X-ray Binary System (IMXB or HMXB).
The inconsistency regarding the distance
between the radio and optical/NIR observations
could be explained by the detection of an interaction
between matter ejected before the X-ray outburst and the surrounding
medium of the source. If this is confirmed, this source could be
added to the short list of microquasars where such an interaction
has been detected.
\end{abstract}

\section{Introduction}

The source $\saxjdhdn$ attracted considerable attention after 
the detection of a giant optical outburst on 1999 September 15.7 UT, 
from the magnitudes 14.0 to 8.8 in the V-band \citep{stubbings:1999}.
The source, in the direction of the galactic bulge,
 was centered on a star called V4641 Sgr in the
catalog of variable stars 
and located in the constellation of Sagittarius \citep{kazarovets:2000}. 
Due to a confusion, most of the references of this X-ray
source are reported to the name of GM Sgr. 
After this confusion was clarified by \citet{williams:1999} and
\citet{samus:1999},
the source was newly designated V4641 Sgr \citep{kazarovets:2000}.
The X-ray source XTE J1819-254 flared, from 1.6 to 12.2 Crab in the X-rays
on 1999, September 14th, as observed by {\it RXTE} in the 2-12 keV band, 
through a brief but dramatic eruption (brightest
source of X-rays in the sky), its position being coincident with
the optical transient \citep{smith:1999}.
Less than 10 hours later, the source was fainter than 50 mCrab.
This source was identified with the previously detected 
faint X-ray transient, $\saxjdhdn$, 
discovered by {\it SAX} on 1999, Feb 20th, 
 \citep{in'tzand:1999} (energy $0.012-0.3$ Crab), 
and independently detected by {\it RXTE}, 
on 1999, Feb 18th \citep{markwardt:1999a}, with an
energy between $<1$ and $80$ mCrab in the 2-10 keV energy band.

\cite{kato:1999} reported an unusual optical activity prior to this giant
optical and X-ray outburst, through a $\sim 1$ mag high-amplitude modulation
6 days before the giant outburst (on Sep. 8th),
and a quasi-periodicity of 2.5 days, which they claimed to 
correspond to the orbital period.
Three other eruptions
followed each lasting less than two hours in the X-rays, ones of the fastest
bursts ever seen. 
The observations by {\it RXTE} \citep{wijnands:2000} 
allowed to observe some strong flaring activity: 
fluctuations by a factor of 4 on the timescale of seconds,
and 500 on minutes. 
No QPO was detected,
but some red noise at $<$ 30 Hz was present.
The observations by {\it SAX} \citep{in'tzand:2000} 
gave a best fit for the column density of
$\nh \sim 0.05 \pm 0.02 \times 10^{22} \cmmoinsdeux$.

The VLA radio telescope detected on Sept. 16.02 UT
a strong radio source of 0.4 Jy at 4.9 GHz, at the
position of the variable star, at 
$\alpha$ = $18\heu 19\hmin 21\hsecp636$,
$\delta$ = $-25\deg 24\amin 25\asecp6$ (J2000) \citep{hjellming:1999a}. 
The galactic coordinates are ($l,b$) = ($6.774015\deg, -4.789045\deg$).
The flux decreased on a timescale of hours, 
with an e-fold decay time of 0.6 day.
The source was resolved, with the presence of an elongation
extending $0.25 \asec$ between 0.6-1.2 day after the huge X-ray flare.
On Sept. 17.93, 22.00 and 24.1 UT, the elongation was at the same position
\citep{hjellming:1999b}.
They claimed that the proper motion was $0.5\asec$ / day, 
but this is strongly
dependent upon the time of the ejection. The 
jets seem to suggest a high inclination angle. 
This allowed to classify the source as a new microquasar
(for a review on the jet sources see \cite{mirabel:1999}).
An HI absorption experiment
towards the source implied a distance $d > 0.4 \kpc$ \citep{hjellming:2000},
and these authors proposed a likely distance of $0.5 \kpc$.

\cite{orosz:2000a} derived from ESO spectroscopic observations
an optical mass function of $2.74 \pm 0.12 \Msol$, which, combined
with the information on the inclination, makes of V4641 a black hole system
with a mass of the compact object $8.73 \leq M_1 \leq 11.70 \Msol$. 
They also found a spectroscopic
period of $2.81678 \pm 0.00056$ days, and assuming an extinction
$E(B-V) = 0.32 \pm 0.10$, quoted a distance between $7.40$ and $12.31 \kpc$
(note that this is bigger than previously derived by \cite{orosz:2000}).

Through our on-going ESO Target of Opportunity program
 aimed at observing new X-ray flaring sources,
we got quickly NIR and optical imaging 
and spectroscopic observations
of this new transient source during its outburst and
we could follow it on its decline for a few months
(from 1999, September to 2000, June).
We report in Section \ref{obs} the main observations and results, 
and discuss them in Section \ref{discussion}.
A more detailed study of this source is reported in Chaty et al. (in prep.).

%__________________________________________________________________

\section{Observations and results} \label{obs}

The optical imaging and spectroscopic observations took place on
1999, September 16, 17, 28 and 29 and on 2000, March 21 and June, 24; 
and the infrared imaging and
spectroscopic observations on 1999, September 19, 20,
22 and 24, and on 2000, March 20. All the observations took
place at ESO, La Silla, but those of June, 24, which were performed 
at the 1.23 m telescope of the Centro
Astron\'omico Hispano Alem\'an at Calar-Alto, 
with the CCD optical camera and exposure times
between 30 and 60s (more details on these observations
are reported in \citet{marti:2001}).
The airmass during the observations was always between 1.008 and 1.020.
The optical observations were performed 
with the NTT telescope and the instrument EMMI RILD.
We imaged the source in V, R and I filters, and took
some spectra with the grism \#1.
The exposure times were nearly 5 min each for the imaging
and 15 min for the spectroscopy.
The infrared observations 
were performed with the NTT and the instrument SOFI.
The imaging was taken through the filters J, H and Ks,
and the spectra with the Grism Red (GR) and 1" slit.
The exposure times were chosen as 15 min for the infrared imaging
and spectroscopy.
The Tables \ref{table_observations_optique} and 
\ref{table_observations_infrarouge} summarize respectively all the different 
optical and infrared observations.
The lightcurves of the overall optical and infrared observations
are respectively reported in Figures \ref{optique_tout} and 
\ref{vir_tout}.
The V-I and J-K colors during the outburst are respectively reported 
in Figures \ref{figure_V-I} and \ref{figure_J-K}.

%---------------------------------------------------------------------------
\begin{table*}
\begin{flushleft}
%\begin{center}
\begin{tabular}{|c|c|c|c|c|c|c|} \hline
{\em Date}      & {\em MJD}     & {\em Inst}    & 
{\em B}   & {\em V} & {\em R} & {\em I} \\ \hline

%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%

16/09/99  & 51438.1 & EMMI      
& - & $13.611\pm0.095$ & $13.325\pm0.1$ & $13.195\pm0.085$ \\
%
17/09/99  & 51439.0& EMMI      
& - & $13.511\pm0.06$  &       -        & $13.045\pm0.08$ \\
%
%
28/09/99  & 51450.0& EMMI             
& - & $13.649\pm0.062$   & $13.603\pm0.012$ & $13.248\pm0.016$ \\
%
29/09/99  & 51451.0& EMMI 
& - & $13.87\pm0.064$  & -                & $13.409\pm0.083$ \\
%
21/03/00  & 51625.4 & EMMI 
& - & $13.889\pm0.116$ & $13.708\pm0.075$ & $13.428\pm0.043$ \\
%
24/06/00 & 51719.5 & C.A.
& $14.32\pm0.05$ & $13.98\pm0.05$   & $13.69\pm0.05$   & $13.27\pm0.05$ \\

%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
\hline
\end{tabular}
\end{flushleft}
%\end{center}
\caption[]{\label{table_observations_optique} {\bf Diary of the 
optical observations.} C.A.: Calar Alto \\
}
\end{table*}

%---------------------------------------------------------------------------
\begin{table*}
\begin{flushleft}
%\begin{center}
\begin{tabular}{|c|c|c|c|c|c|c|} \hline
{\em Date} & {\em MJD}& {\em Inst} & {\em J     } &  {\em H} &  {\em Ks} & {\em J-Ks}     \\ \hline

%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%

%
19/09/99  & 51441.0& SOFI      
& $13.14\pm0.113$  & -              & $13.095\pm0.04$  & 0.045 $\pm$ 0.153 \\
%
20/09/99  & 51441.98& SOFI 
& $12.989\pm0.026$ & -              & $12.809\pm0.056$ & 0.18  $\pm$0.082 \\
%
22/09/99  & 51443.97& SOFI      
& $13.927\pm0.03$    & -              & $13.056\pm0.058$ & 0.870 $\pm$ 0.088 \\
%
24/09/99  & 51445.98& SOFI           
& $14.033\pm0.027$   & -              & $13.719\pm0.029$ & 0.314 $\pm$0.056 \\
%
20/03/00  & 51623.42& SOFI             
& $12.944\pm0.007$   & $12.849\pm0.01$  & $12.723\pm0.013$ & 0.221 $\pm$0.02 \\
%
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
\hline
\end{tabular}
\end{flushleft}
%\end{center}
\caption[]{\label{table_observations_infrarouge} {\bf Diary of the infrared observations.} \\
}
\end{table*}
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%

After the big outburst (from V=14 to 8.8 mag), 
there was still some flaring activity in V, R and I
with variations of $\sim 0.5$ mag with no significant change in the colors.
In NIR there was also 
some flaring activity with variation of $\sim 1$ mag in J and K,
with a significant change in the J-K color during the post-outburst
(between 2 and 5 days after the giant outburst).
This suggests an increased K-contribution compared to J, which 
can be explained either by the emission of a jet,
or the appearance of heated dust (as seen in the case of $\grs$
by \cite{mirabel:1996a}), or even by the interaction 
with the interstellar medium.

We report the normalized
optical spectra offset to get an easier reading 
in Figure \ref{spec_opt_norm}.
The first striking fact is that on a timescale of one day,
the lines were changing from emission to absorption.
All the Balmer serie is visible: H$\alpha$, $\beta$, $\gamma$, $\delta$, 
$\epsilon$, $\zeta$...
The H$\alpha$ emission line is extraordinarily strong: 
one day after the outburst, its
equivalent width was $\sim 100 \AA$, with a FWZI of 
$\sim 6700 \kms$ and a blue wing.
There was also a strong He I $5876 \AA$.
The Na-D absorption line equivalent width of $0.45 \AA$ gives E(B-V) = 0.25 
\citep{munari:1997} implying 
$\nh = 0.14 \times 10^{22} \cmmoinsdeux$ \citep{bohlin:1978}.
There is a strong variability of the lines: 
Balmer H$\alpha$, H$\beta$ and also of He I.
The He II $4680 \AA$ line was claimed to be prominent in emission 
nearer to the outburst time 
by \cite{ayani:1999}. Since we could not detect it, this line
was also very variable.
We can also note the blue continuum, visible on the flux calibrated spectra,
suggesting the emission from an accretion disk, or from a corona.

In the NIR, the He I and Br $\gamma$ lines were observed as strong
lines by \cite{charles:1999a}, in a UKIRT/CGS4 spectrum taken
on Sept 17.22 UT. 
He I exhibited an equivalent width of  2.1 nm, and Br $\gamma$ of 1.4 nm,
both showing extended blue wings (FWZI=5900 km/s),
suggesting a high velocity wind component \citep{charles:1999a}.
The continuum of our NIR spectrum was blue, like the spectrum from
\cite{charles:1999a}.
However, our NIR spectrum shows only 
very faint HeI, He II and Br$\gamma$ lines,
which appear therefore to be strongly variable.
The emission lines and the variability suggest the
 accretion of matter onto a compact
object with a high-velocity wind component ($\sim 6000 \kms$), 
also perhaps the presence of a cocoon or a jet.

\section{Discussion} \label{discussion}

\subsection{Nature of the system: the companion star}

We plotted on a color-magnitude diagram (CMD, Figure \ref{hr})
the optical and NIR magnitudes when the source was faint.
We plotted in this figure the absolute magnitudes corrected for 
three different values of the absorption, and corresponding to
ten different values of the distance of the source.
The values of the absorption correspond 
to $0.05$, $0.1$ and $0.15 \times 10^{22} \cmmoinsdeux$,
derived from our observations and from {\it SAX} observations 
\citep{in'tzand:2000}.
The values of the distance of the source go 
from 1 to $10 \kpc$.
If we constrain the companion object of the binary system 
to be a main sequence star, 
its location on the CMD, 
taking into account the uncertainty on the absorption,
suggests that the distance is constrained to
$3 < d < 8 \kpc$.
Its spectral type is in this case
consistent with an early type B3 - A2 V main sequence star.

However, it is interesting to note that the companion star could
be crossing the Hertzsprung gap (U. Kolb, private communication), 
as for GRO J1655-40 \citep{kolb:1997}, although 
the mass of the companion star in the case of V4641 Sgr
is bigger than for GRO J1655-40.
In this view, the location on the CMD would be above
the main sequence, the distance of the object could
then be still bigger than $3 < d < 8 \kpc$, this range
becoming its minimum distance, and the spectral type would be
B3 - A2 IV.
In both possibilities the mass is constrained between 2 $<$ M $<$ 10 $\Msol$,
suggesting that it is an IMXB or a HMXB.
This is consistent with the results derived by \cite{orosz:2000a}.

\subsection{The jets: a new microquasar?}

If the elongation seen in the radio was a moving component, 
the proper motion was between $224 < \mu < 788$ mas/d depending on the
exact time of the ejection.
For the sake of discussion, we will assume that this is the
approaching (brighter) condensation with $\mu_a = 500$ mas/d.
Since $D\leq \frac{c}{\sqrt{\mu_a \mu_r}}$,
and from our results $D \geq 3 \kpc$, we conclude that the apparent
velocity in the plane of the sky would be strongly superluminal,
$v_a$ greater than $8 c$ at the distance of $3 \kpc$.
However, 
no movement of this elongation was detected between Sept. 16.02 and 24.1.
This suggests an interaction with surroundings at 
$0.25 \asec$ $\geq 1.5 \times 10^3$ AU at the distance of 6 kpc.
This is possible if the ejections began to take place at least 10 days before
the radio detection e.g. on September, $8^{th}$, and we can
see from Figure \ref{figure_V-I} that the source was already active
in the optical at this date.

It seems therefore that the activity of this source was not as sporadic
as we could have thought at the beginning.
Indeed, a previous optical outburst 
occured in 1999, August \citep{watanabe:1999}, 
and {\it RXTE} could detect this source during 270 days
before the giant outburst (in't Zand; Markwardt, these proceedings).
Furthermore, during 5 days before the giant outburst, 
the source was in the optical continuously
2 magnitudes brighter than immediately after, showing a modulation
at the orbital period, with no X-ray emission
(typical upper limit of 12 mCrab, \citet{in'tzand:2000}).
All these facts, combined to the high X-ray variability,
show that, although the \citet{orosz:2000a} 
results suggest that the accretion
in the system is of Roche-lobe overflow type, it could exist
in addition a mass loss from the vicinity of the compact
object.
At a distance of $6 \kpc$, the maximum
luminosity of the source is $\sim 4 \times 10^{38} \ergs$, therefore
close to the Eddington limit of a $\sim 10 \Msol$ object 
($1.3 \times 10^{39} \ergs$). If the transfer rate is highly super-Eddington
such a wind could arise.
This wind could be the reason why surrounding matter
was present, allowing the interaction between further ejections
and surrounding matter to take place.
In this case, the companion star is more likely to be a main sequence
star (U. Kolb, private communication).

Finally, it is interesting to note that \citet{marti:2001} observed
this source to look for minute to hour variability, 
discovering a 0.1 mag variability on the time scale of hours.
Among the different interpretations considered by them, 
it is suggested that this variability could originate in an extended corona
surrounding the jets, by analogy with SS 433.
If this interaction between the jets and the surrounding medium is confirmed, 
this source could therefore be added
to the short list of microquasars where such an interaction has
been detected (see e.g. \cite{mirabel:1999} \& \cite{chaty:2001}).

\section{Conclusions}

From our optical and the {\it SAX} observations we constrained
$0.05 < \nh < 0.15 \times 10^{22} \cmmoinsdeux$. From our
optical and NIR colors the distance is $3 < D < 8 \kpc$,
and the companion star would be a main sequence star of spectral type 
B3 - A2 V.
If the source is crossing the Hertzsprung gap,
this determination of the distance would become its minimum distance,
and the spectral type of the companion star would be B3 - A2 IV. 
The system is therefore an IMXB or a HMXB.
From the radio images, the NIR colors, and the optical spectra,
there is a strong suggestion of interaction of the ejecta
of the source with its surroundings.
This surrounding matter could have originated from a
wind created by fluctuations around the central object,
and in this case the companion star would more certainly
be a main sequence star.
Further observations would be useful to confirm this existence
of surrounding matter.

\section*{acknowledgements}
S.C. thanks Rob Hynes for poiting out this new
flaring source on September 1999, Bob Hjellming
for all the spontaneous communications he gave on the radio
observations of this source, and Ulrich Kolb for many stimulating
discussions and careful rereading of the manuscript. 
S.C. is very grateful to the ESO staff for their availability and skills
to perform service observations for override programs,
and in particular to the NTT team: Leonardo Vanzi, Olivier Hainaut,
St\'ephane Brillant and Vanessa Doublier.
S.C. acknowledges
support from grant F/00-180/A from the Leverhulme Trust.
IFM acknowledges partial support from Conicet/Argentina.
JM acknowledges partial support by DGICYT (PB97-0903) and Junta de
Andaluc\'{\i}a (Spain).

   \bibliographystyle{aa}
   \bibliography{science}
% The results are inserted directly here to simplify
% the demonstration.

%\begin{thebibliography}{}
%\bibitem[Allen(1973)]{allen73}
%Allen C., 1973, Astrophysical Quantities, Athlone Press
%
%\bibitem[Nobody et~al.(1997)]{nobody97}
%Nobody B., Somebody G., Who M.E., et~al., 1997, ApJ 331, 902
%
%\bibitem[Smith \& Jones(1996)]{smith96}
%Smith A., Jones B., 1996, A\&A 555, 999
%
%\end{thebibliography}

%---------------------------------------------------------------------------
%\begin{table*}
%\begin{flushleft}
%%\begin{center}
%\begin{tabular}{|c|c|c|c|c|c|c|c|c|} \hline
%{\em Date}      & {\em MJD}     & {\em Inst}    & 
%{\em B}   & {\em V} & {\em R} & {\em I} & {\em Z} 
%& sp\\ \hline


\twocolumn
\newpage

%%% TOUTES LES FIGURES

%---------------------------------------------------------------------------
\begin{figure}
\centerline{\psfig{file=sax_v_nb.ps,angle=+90.,width=8.9cm}}
\caption[]{Optical Observations. +:VSNET, $\triangle$: B, $\times$:V, $\ast$:R, $\diamond$:I magnitudes. 
The beginning of the optical activity took place on 1999 Sept. 8 UT
(= MJD 51429.5), followed by the outburst of 1999 Sept. 15.7 UT (= MJD 51437).
\label{optique_tout}}
\end{figure}
%---------------------------------------------------------------------------

%%---------------------------------------------------------------------------
\begin{figure}
\centerline{\psfig{file=sax_vir_nb.ps,angle=+90.,width=8.9cm}}
\caption[]{NIR (+ optical) observations. 
+:VSNET, $\times$:V, $\ast$:J, $\Box$: H, 
$\diamond$:Ks magnitudes. \label{vir_tout}}
\end{figure}
%---------------------------------------------------------------------------

%---------------------------------------------------------------------------
\begin{figure}
\centerline{\psfig{file=v-i_zoom2.ps,angle=+90.,width=9.cm}}
\caption[]{Top: +:VSNET, $\times$:V, $\triangle$:I magnitudes. 
Bottom: V-I color. \label{figure_V-I}}
\end{figure}
%---------------------------------------------------------------------------

%---------------------------------------------------------------------------
\begin{figure}
\centerline{\psfig{file=j-k_zoom1.ps,angle=+90.,width=8.9cm}}
\caption[]{Top: +:VSNET, $\times$:V, $\ast$:J, $\diamond$:Ks magnitudes). 
Bottom: J-Ks color. \label{figure_J-K}}
\end{figure}
%---------------------------------------------------------------------------

%---------------------------------------------------------------------------
\begin{figure}
\centerline{\psfig{file=tous_lab.eps,angle=+90.,width=9.cm}}
\caption[]{Normalized and offset optical spectra. \label{spec_opt_norm}}
\end{figure}
%---------------------------------------------------------------------------

%---------------------------------------------------------------------------
\begin{figure}
\centerline{\psfig{file=vk_kctoutzoom2.ps,angle=+90.,width=9.cm}}
\caption[]{Color-magnitude [V-Ks,Ks] diagram. *: Min magnitudes of V4641 Sgr. 
+: typical main sequence stars \citep{ruelas-mayorga:1991}. 
0.28, 0.56 and 0.84 are the visual absorptions
corresponding respectively to the column densities 
$0.05$, $0.1$ and $0.15 \times 10^{22} \cmmoinsdeux$.
\label{hr}}
\end{figure}
%---------------------------------------------------------------------------

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psfig.tex
% Psfig/TeX 
\def\PsfigVersion{1.10}
\def\setDriver{\DvipsDriver} % \DvipsDriver or \OzTeXDriver
%
% All software, documentation, and related files in this distribution of
% psfig/tex are Copyright 1993 Trevor J. Darrell
%
% Permission is granted for use and non-profit distribution of psfig/tex 
% providing that this notice is clearly maintained. The right to
% distribute any portion of psfig/tex for profit or as part of any commercial
% product is specifically reserved for the author(s) of that portion.
%
% To use with LaTeX, use \documentstyle[psfig,...]{...}
% To use with TeX, use \input psfig.sty
%
% Bugs and improvements to trevor@media.mit.edu.
%
% Thanks to Ned Batchelder, Greg Hager (GDH), J. Daniel Smith (JDS),
% Tom Rokicki (TR), Robert Russell (RR), George V. Reilly (GVR),
% Ken McGlothlen (KHC), Baron Grey (BG), Gerhard Tobermann (GT).
% and all others who have contributed code and comments to this project!
%
% ======================================================================
% Modification History:
%
%  9 Oct 1990   JDS	used more robust bbox reading code from Tom Rokicki
% 29 Mar 1991   JDS	implemented rotation= option
% 25 Jun 1991   RR	if bb specified on cmd line don't check
%			for .ps file.
%  3 Jul 1991	JDS	check if file already read in once
%  4 Sep 1991	JDS	fixed incorrect computation of rotated
%			bounding box
% 25 Sep 1991	GVR	expanded synopsis of \psfig
% 14 Oct 1991	JDS	\fbox code from LaTeX so \psdraft works with TeX
%			changed \typeout to \ps@typeout
% 17 Oct 1991	JDS	added \psscalefirst and \psrotatefirst
% 23 Jun 1993   KHC     ``doclip'' must appear before ``rotate''
% 27 Oct 1993   TJD	removed printing of filename to avoid 
%			underscore problems. changed \frame to \fbox.
%			Added OzTeX support from BG. Added new
%			figure search path code from GT.
% 23 Nov 1993	EP	support for .gz (gzipped) files, searched before .Z
%
% ======================================================================
%
% Command synopsis:
%
% \psdraft	draws an outline box, but doesn't include the figure
%		in the DVI file.  Useful for previewing.
%
% \psfull	includes the figure in the DVI file (default).
%
% \psscalefirst width= or height= specifies the size of the figure
% 		before rotation.
% \psrotatefirst (default) width= or height= specifies the size of the
% 		 figure after rotation.  Asymetric figures will
% 		 appear to shrink.
%
% \psfigurepath{dir:dir:...}  sets the path to search for the figure
%
% \psfig
% usage: \psfig{file=, figure=, height=, width=,
%			bbllx=, bblly=, bburx=, bbury=,
%			rheight=, rwidth=, clip=, angle=, silent=}
%
%	"file" is the filename.  If no path name is specified and the
%		file is not found in the current directory,
%		it will be looked for in directory \psfigurepath.
%	"figure" is a synonym for "file".
%	By default, the width and height of the figure are taken from
%		the BoundingBox of the figure.
%	If "width" is specified, the figure is scaled so that it has
%		the specified width.  Its height changes proportionately.
%	If "height" is specified, the figure is scaled so that it has
%		the specified height.  Its width changes proportionately.
%	If both "width" and "height" are specified, the figure is scaled
%		anamorphically.
%	"bbllx", "bblly", "bburx", and "bbury" control the PostScript
%		BoundingBox.  If these four values are specified
%               *before* the "file" option, the PSFIG will not try to
%               open the PostScript file.
%	"rheight" and "rwidth" are the reserved height and width
%		of the figure, i.e., how big TeX actually thinks
%		the figure is.  They default to "width" and "height".
%	The "clip" option ensures that no portion of the figure will
%		appear outside its BoundingBox.  "clip=" is a switch and
%		takes no value, but the `=' must be present.
%	The "angle" option specifies the angle of rotation (degrees, ccw).
%	The "silent" option makes \psfig work silently.
%
% ======================================================================
% check to see if macros already loaded in (maybe some other file says
% "\input psfig") ...
\ifx\undefined\psfig\else\endinput\fi
%
% from a suggestion by eijkhout@csrd.uiuc.edu to allow
% loading as a style file. Changed to avoid problems
% with amstex per suggestion by jbence@math.ucla.edu

\let\LaTeXAtSign=\@
\let\@=\relax
\edef\psfigRestoreAt{\catcode`\@=\number\catcode`@\relax}
%\edef\psfigRestoreAt{\catcode`@=\number\catcode`@\relax}
\catcode`\@=11\relax
\newwrite\@unused
\def\ps@typeout#1{{\let\protect\string\immediate\write\@unused{#1}}}

\def\DvipsDriver{
	\ps@typeout{psfig/tex \PsfigVersion -dvips}
\def\PsfigSpecials{\DvipsSpecials} 	\def\ps@dir{/}
\def\ps@predir{} }
\def\OzTeXDriver{
	\ps@typeout{psfig/tex \PsfigVersion -oztex}
	\def\PsfigSpecials{\OzTeXSpecials}
	\def\ps@dir{:}
	\def\ps@predir{:}
	\catcode`\^^J=5
}

%% Here's how you define your figure path.  Should be set up with null
%% default and a user useable definition.

\def\figurepath{./:}
\def\psfigurepath#1{\edef\figurepath{#1:}}

%%% inserted for Searching Unixpaths
%%% (the path must end with :)
%%% (call: \DoPaths\figurepath )
%%%------------------------------------------------------
\def\DoPaths#1{\expandafter\EachPath#1\stoplist}
%
\def\leer{}
\def\EachPath#1:#2\stoplist{% #1 part of the list (delimiter :)
  \ExistsFile{#1}{\SearchedFile}
  \ifx#2\leer
  \else
    \expandafter\EachPath#2\stoplist
  \fi}
%
% exists the file (does not work for directories!)
%
\def\ps@dir{/}
\def\ExistsFile#1#2{%
   \openin1=\ps@predir#1\ps@dir#2
   \ifeof1
       \closein1
       %\ps@typeout{...not: \ps@predir#1\ps@dir#2}
   \else
       \closein1
       %\ps@typeout{...in:  \ps@predir#1\ps@dir#2}
        \ifx\ps@founddir\leer
          %\ps@typeout{set founddir #1}
           \edef\ps@founddir{#1}
        \fi
   \fi}
%------------------------------------------------------
%
% Get dir in path or error
%
\def\get@dir#1{%
  \def\ps@founddir{}
  \def\SearchedFile{#1}
  \DoPaths\figurepath
%  \fi
}
%------------------------------------------------------
%%% END of Searching Unixpaths


%
% @psdo control structure -- similar to Latex @for.
% I redefined these with different names so that psfig can
% be used with TeX as well as LaTeX, and so that it will not 
% be vunerable to future changes in LaTeX's internal
% control structure,
%
\def\@nnil{\@nil}
\def\@empty{}
\def\@psdonoop#1\@@#2#3{}
\def\@psdo#1:=#2\do#3{\edef\@psdotmp{#2}\ifx\@psdotmp\@empty \else
    \expandafter\@psdoloop#2,\@nil,\@nil\@@#1{#3}\fi}
\def\@psdoloop#1,#2,#3\@@#4#5{\def#4{#1}\ifx #4\@nnil \else
       #5\def#4{#2}\ifx #4\@nnil \else#5\@ipsdoloop #3\@@#4{#5}\fi\fi}
\def\@ipsdoloop#1,#2\@@#3#4{\def#3{#1}\ifx #3\@nnil 
       \let\@nextwhile=\@psdonoop \else
      #4\relax\let\@nextwhile=\@ipsdoloop\fi\@nextwhile#2\@@#3{#4}}
\def\@tpsdo#1:=#2\do#3{\xdef\@psdotmp{#2}\ifx\@psdotmp\@empty \else
    \@tpsdoloop#2\@nil\@nil\@@#1{#3}\fi}
\def\@tpsdoloop#1#2\@@#3#4{\def#3{#1}\ifx #3\@nnil 
       \let\@nextwhile=\@psdonoop \else
      #4\relax\let\@nextwhile=\@tpsdoloop\fi\@nextwhile#2\@@#3{#4}}
% 
% \fbox is defined in latex.tex; so if \fbox is undefined, assume that
% we are not in LaTeX.
% Perhaps this could be done better???
\ifx\undefined\fbox
% \fbox code from modified slightly from LaTeX
\newdimen\fboxrule
\newdimen\fboxsep
\newdimen\ps@tempdima
\newbox\ps@tempboxa
\fboxsep = 3pt
\fboxrule = .4pt
\long\def\fbox#1{\leavevmode\setbox\ps@tempboxa\hbox{#1}\ps@tempdima\fboxrule
    \advance\ps@tempdima \fboxsep \advance\ps@tempdima \dp\ps@tempboxa
   \hbox{\lower \ps@tempdima\hbox
  {\vbox{\hrule height \fboxrule
          \hbox{\vrule width \fboxrule \hskip\fboxsep
          \vbox{\vskip\fboxsep \box\ps@tempboxa\vskip\fboxsep}\hskip 
                 \fboxsep\vrule width \fboxrule}
                 \hrule height \fboxrule}}}}
\fi
%
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
% file reading stuff from epsf.tex
%   EPSF.TEX macro file:
%   Written by Tomas Rokicki of Radical Eye Software, 29 Mar 1989.
%   Revised by Don Knuth, 3 Jan 1990.
%   Revised by Tomas Rokicki to accept bounding boxes with no
%      space after the colon, 18 Jul 1990.
%   Portions modified/removed for use in PSFIG package by
%      J. Daniel Smith, 9 October 1990.
%
\newread\ps@stream
\newif\ifnot@eof       % continue looking for the bounding box?
\newif\if@noisy        % report what you're making?
\newif\if@atend        % %%BoundingBox: has (at end) specification
\newif\if@psfile       % does this look like a PostScript file?
%
% PostScript files should start with `%!'
%
{\catcode`\%=12\global\gdef\epsf@start{%!}}
\def\epsf@PS{PS}
%
\def\epsf@getbb#1{%
%
%   The first thing we need to do is to open the
%   PostScript file, if possible.
%
\openin\ps@stream=\ps@predir#1
\ifeof\ps@stream\ps@typeout{Error, File #1 not found}\else
%
%   Okay, we got it. Now we'll scan lines until we find one that doesn't
%   start with %. We're looking for the bounding box comment.
%
   {\not@eoftrue \chardef\other=12
    \def\do##1{\catcode`##1=\other}\dospecials \catcode`\ =10
    \loop
       \if@psfile
	  \read\ps@stream to \epsf@fileline
       \else{
	  \obeyspaces
          \read\ps@stream to \epsf@tmp\global\let\epsf@fileline\epsf@tmp}
       \fi
       \ifeof\ps@stream\not@eoffalse\else
%
%   Check the first line for `%!'.  Issue a warning message if its not
%   there, since the file might not be a PostScript file.
%
       \if@psfile\else
       \expandafter\epsf@test\epsf@fileline:. \\%
       \fi
%
%   We check to see if the first character is a % sign;
%   if so, we look further and stop only if the line begins with
%   `%%BoundingBox:' and the `(atend)' specification was not found.
%   That is, the only way to stop is when the end of file is reached,
%   or a `%%BoundingBox: llx lly urx ury' line is found.
%
          \expandafter\epsf@aux\epsf@fileline:. \\%
       \fi
   \ifnot@eof\repeat
   }\closein\ps@stream\fi}%
%
% This tests if the file we are reading looks like a PostScript file.
%
\long\def\epsf@test#1#2#3:#4\\{\def\epsf@testit{#1#2}
			\ifx\epsf@testit\epsf@start\else
\ps@typeout{Warning! File does not start with `\epsf@start'.  It may not be a PostScript file.}
			\fi
			\@psfiletrue} % don't test after 1st line
%
%   We still need to define the tricky \epsf@aux macro. This requires
%   a couple of magic constants for comparison purposes.
%
{\catcode`\%=12\global\let\epsf@percent=%\global\def\epsf@bblit{%BoundingBox}}
%
%
%   So we're ready to check for `%BoundingBox:' and to grab the
%   values if they are found.  We continue searching if `(at end)'
%   was found after the `%BoundingBox:'.
%
\long\def\epsf@aux#1#2:#3\\{\ifx#1\epsf@percent
   \def\epsf@testit{#2}\ifx\epsf@testit\epsf@bblit
	\@atendfalse
        \epsf@atend #3 . \\%
	\if@atend	
	   \if@verbose{
		\ps@typeout{psfig: found `(atend)'; continuing search}
	   }\fi
        \else
        \epsf@grab #3 . . . \\%
        \not@eoffalse
        \global\no@bbfalse
        \fi
   \fi\fi}%
%
%   Here we grab the values and stuff them in the appropriate definitions.
%
\def\epsf@grab #1 #2 #3 #4 #5\\{%
   \global\def\epsf@llx{#1}\ifx\epsf@llx\empty
      \epsf@grab #2 #3 #4 #5 .\\\else
   \global\def\epsf@lly{#2}%
   \global\def\epsf@urx{#3}\global\def\epsf@ury{#4}\fi}%
%
% Determine if the stuff following the %%BoundingBox is `(atend)'
% J. Daniel Smith.  Copied from \epsf@grab above.
%
\def\epsf@atendlit{(atend)} 
\def\epsf@atend #1 #2 #3\\{%
   \def\epsf@tmp{#1}\ifx\epsf@tmp\empty
      \epsf@atend #2 #3 .\\\else
   \ifx\epsf@tmp\epsf@atendlit\@atendtrue\fi\fi}


% End of file reading stuff from epsf.tex
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%

%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
% trigonometry stuff from "trig.tex"
\chardef\psletter = 11 % won't conflict with \begin{letter} now...
\chardef\other = 12

\newif \ifdebug %%% turn me on to see TeX hard at work ...
\newif\ifc@mpute %%% don't need to compute some values
\c@mputetrue % but assume that we do

\let\then = \relax
\def\r@dian{pt }
\let\r@dians = \r@dian
\let\dimensionless@nit = \r@dian
\let\dimensionless@nits = \dimensionless@nit
\def\internal@nit{sp }
\let\internal@nits = \internal@nit
\newif\ifstillc@nverging
\def \Mess@ge #1{\ifdebug \then \message {#1} \fi}

{ %%% Things that need abnormal catcodes %%%
	\catcode `\@ = \psletter
	\gdef \nodimen {\expandafter \n@dimen \the \dimen}
	\gdef \term #1 #2 #3%
	       {\edef \t@ {\the #1}%%% freeze parameter 1 (count, by value)
		\edef \t@@ {\expandafter \n@dimen \the #2\r@dian}%
				   %%% freeze parameter 2 (dimen, by value)
		\t@rm {\t@} {\t@@} {#3}%
	       }
	\gdef \t@rm #1 #2 #3%
	       {{%
		\count 0 = 0
		\dimen 0 = 1 \dimensionless@nit
		\dimen 2 = #2\relax
		\Mess@ge {Calculating term #1 of \nodimen 2}%
		\loop
		\ifnum	\count 0 < #1
		\then	\advance \count 0 by 1
			\Mess@ge {Iteration \the \count 0 \space}%
			\Multiply \dimen 0 by {\dimen 2}%
			\Mess@ge {After multiplication, term = \nodimen 0}%
			\Divide \dimen 0 by {\count 0}%
			\Mess@ge {After division, term = \nodimen 0}%
		\repeat
		\Mess@ge {Final value for term #1 of 
				\nodimen 2 \space is \nodimen 0}%
		\xdef \Term {#3 = \nodimen 0 \r@dians}%
		\aftergroup \Term
	       }}
	\catcode `\p = \other
	\catcode `\t = \other
	\gdef \n@dimen #1pt{#1} %%% throw away the ``pt''
}

\def \Divide #1by #2{\divide #1 by #2} %%% just a synonym

\def \Multiply #1by #2%%% allows division of a dimen by a dimen
       {{%%% should really freeze parameter 2 (dimen, passed by value)
	\count 0 = #1\relax
	\count 2 = #2\relax
	\count 4 = 65536
	\Mess@ge {Before scaling, count 0 = \the \count 0 \space and
			count 2 = \the \count 2}%
	\ifnum	\count 0 > 32767 %%% do our best to avoid overflow
	\then	\divide \count 0 by 4
		\divide \count 4 by 4
	\else	\ifnum	\count 0 < -32767
		\then	\divide \count 0 by 4
			\divide \count 4 by 4
		\else
		\fi
	\fi
	\ifnum	\count 2 > 32767 %%% while retaining reasonable accuracy
	\then	\divide \count 2 by 4
		\divide \count 4 by 4
	\else	\ifnum	\count 2 < -32767
		\then	\divide \count 2 by 4
			\divide \count 4 by 4
		\else
		\fi
	\fi
	\multiply \count 0 by \count 2
	\divide \count 0 by \count 4
	\xdef \product {#1 = \the \count 0 \internal@nits}%
	\aftergroup \product
       }}

\def\r@duce{\ifdim\dimen0 > 90\r@dian \then   % sin(x+90) = sin(180-x)
		\multiply\dimen0 by -1
		\advance\dimen0 by 180\r@dian
		\r@duce
	    \else \ifdim\dimen0 < -90\r@dian \then  % sin(-x) = sin(360+x)
		\advance\dimen0 by 360\r@dian
		\r@duce
		\fi
	    \fi}

\def\Sine#1%
       {{%
	\dimen 0 = #1 \r@dian
	\r@duce
	\ifdim\dimen0 = -90\r@dian \then
	   \dimen4 = -1\r@dian
	   \c@mputefalse
	\fi
	\ifdim\dimen0 = 90\r@dian \then
	   \dimen4 = 1\r@dian
	   \c@mputefalse
	\fi
	\ifdim\dimen0 = 0\r@dian \then
	   \dimen4 = 0\r@dian
	   \c@mputefalse
	\fi
%
	\ifc@mpute \then
        	% convert degrees to radians
		\divide\dimen0 by 180
		\dimen0=3.141592654\dimen0
%
		\dimen 2 = 3.1415926535897963\r@dian %%% a well-known constant
		\divide\dimen 2 by 2 %%% we only deal with -pi/2 : pi/2
		\Mess@ge {Sin: calculating Sin of \nodimen 0}%
		\count 0 = 1 %%% see power-series expansion for sine
		\dimen 2 = 1 \r@dian %%% ditto
		\dimen 4 = 0 \r@dian %%% ditto
		\loop
			\ifnum	\dimen 2 = 0 %%% then we've done
			\then	\stillc@nvergingfalse 
			\else	\stillc@nvergingtrue
			\fi
			\ifstillc@nverging %%% then calculate next term
			\then	\term {\count 0} {\dimen 0} {\dimen 2}%
				\advance \count 0 by 2
				\count 2 = \count 0
				\divide \count 2 by 2
				\ifodd	\count 2 %%% signs alternate
				\then	\advance \dimen 4 by \dimen 2
				\else	\advance \dimen 4 by -\dimen 2
				\fi
		\repeat
	\fi		
			\xdef \sine {\nodimen 4}%
       }}

% Now the Cosine can be calculated easily by calling \Sine
\def\Cosine#1{\ifx\sine\UnDefined\edef\Savesine{\relax}\else
		             \edef\Savesine{\sine}\fi
	{\dimen0=#1\r@dian\advance\dimen0 by 90\r@dian
	 \Sine{\nodimen 0}
	 \xdef\cosine{\sine}
	 \xdef\sine{\Savesine}}}	      
% end of trig stuff
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%

\def\psdraft{
	\def\@psdraft{0}
	%\ps@typeout{draft level now is \@psdraft \space . }
}
\def\psfull{
	\def\@psdraft{100}
	%\ps@typeout{draft level now is \@psdraft \space . }
}

\psfull

\newif\if@scalefirst
\def\psscalefirst{\@scalefirsttrue}
\def\psrotatefirst{\@scalefirstfalse}
\psrotatefirst

\newif\if@draftbox
\def\psnodraftbox{
	\@draftboxfalse
}
\def\psdraftbox{
	\@draftboxtrue
}
\@draftboxtrue

\newif\if@prologfile
\newif\if@postlogfile
\def\pssilent{
	\@noisyfalse
}
\def\psnoisy{
	\@noisytrue
}
\psnoisy
%%% These are for the option list.
%%% A specification of the form a = b maps to calling \@p@@sa{b}
\newif\if@bbllx
\newif\if@bblly
\newif\if@bburx
\newif\if@bbury
\newif\if@height
\newif\if@width
\newif\if@rheight
\newif\if@rwidth
\newif\if@angle
\newif\if@clip
\newif\if@verbose
\def\@p@@sclip#1{\@cliptrue}
%
%
\newif\if@decmpr
%
\def\@p@@sfigure#1{\def\@p@sfile{null}\def\@p@sbbfile{null}\@decmprfalse
   % look directly for file (e.g. absolute path)
   \openin1=\ps@predir#1
   \ifeof1
	\closein1
	% failed, search directories for file
	\get@dir{#1}
	\ifx\ps@founddir\leer
		% failed, search directly for file.bb
		\openin1=\ps@predir#1.bb
		\ifeof1
			\closein1
			% failed, search directories for file.bb
			\get@dir{#1.bb}
			\ifx\ps@founddir\leer
				% failed, lose.
				\ps@typeout{Can't find #1 in \figurepath}
			\else
				% found file.bb in search dir
				\@decmprtrue
				\def\@p@sfile{\ps@founddir\ps@dir#1}
				\def\@p@sbbfile{\ps@founddir\ps@dir#1.bb}
			\fi
		\else
			\closein1
			%found file.bb directly
			\@decmprtrue
			\def\@p@sfile{#1}
			\def\@p@sbbfile{#1.bb}
		\fi
	\else
		% found file in search dir
		\def\@p@sfile{\ps@founddir\ps@dir#1}
		\def\@p@sbbfile{\ps@founddir\ps@dir#1}
	\fi
   \else
	% found file directly
	\closein1
	\def\@p@sfile{#1}
	\def\@p@sbbfile{#1}
   \fi
}
%
%
%
\def\@p@@sfile#1{\@p@@sfigure{#1}}
%
\def\@p@@sbbllx#1{
		%\ps@typeout{bbllx is #1}
		\@bbllxtrue
		\dimen100=#1
		\edef\@p@sbbllx{\number\dimen100}
}
\def\@p@@sbblly#1{
		%\ps@typeout{bblly is #1}
		\@bbllytrue
		\dimen100=#1
		\edef\@p@sbblly{\number\dimen100}
}
\def\@p@@sbburx#1{
		%\ps@typeout{bburx is #1}
		\@bburxtrue
		\dimen100=#1
		\edef\@p@sbburx{\number\dimen100}
}
\def\@p@@sbbury#1{
		%\ps@typeout{bbury is #1}
		\@bburytrue
		\dimen100=#1
		\edef\@p@sbbury{\number\dimen100}
}
\def\@p@@sheight#1{
		\@heighttrue
		\dimen100=#1
   		\edef\@p@sheight{\number\dimen100}
		%\ps@typeout{Height is \@p@sheight}
}
\def\@p@@swidth#1{
		%\ps@typeout{Width is #1}
		\@widthtrue
		\dimen100=#1
		\edef\@p@swidth{\number\dimen100}
}
\def\@p@@srheight#1{
		%\ps@typeout{Reserved height is #1}
		\@rheighttrue
		\dimen100=#1
		\edef\@p@srheight{\number\dimen100}
}
\def\@p@@srwidth#1{
		%\ps@typeout{Reserved width is #1}
		\@rwidthtrue
		\dimen100=#1
		\edef\@p@srwidth{\number\dimen100}
}
\def\@p@@sangle#1{
		%\ps@typeout{Rotation is #1}
		\@angletrue
%		\dimen100=#1
		\edef\@p@sangle{#1} %\number\dimen100}
}
\def\@p@@ssilent#1{ 
		\@verbosefalse
}
\def\@p@@sprolog#1{\@prologfiletrue\def\@prologfileval{#1}}
\def\@p@@spostlog#1{\@postlogfiletrue\def\@postlogfileval{#1}}
\def\@cs@name#1{\csname #1\endcsname}
\def\@setparms#1=#2,{\@cs@name{@p@@s#1}{#2}}
%
% initialize the defaults (size the size of the figure)
%
\def\ps@init@parms{
		\@bbllxfalse \@bbllyfalse
		\@bburxfalse \@bburyfalse
		\@heightfalse \@widthfalse
		\@rheightfalse \@rwidthfalse
		\def\@p@sbbllx{}\def\@p@sbblly{}
		\def\@p@sbburx{}\def\@p@sbbury{}
		\def\@p@sheight{}\def\@p@swidth{}
		\def\@p@srheight{}\def\@p@srwidth{}
		\def\@p@sangle{0}
		\def\@p@sfile{} \def\@p@sbbfile{}
		\def\@p@scost{10}
		\def\@sc{}
		\@prologfilefalse
		\@postlogfilefalse
		\@clipfalse
		\if@noisy
			\@verbosetrue
		\else
			\@verbosefalse
		\fi
}
%
% Go through the options setting things up.
%
\def\parse@ps@parms#1{
	 	\@psdo\@psfiga:=#1\do
		   {\expandafter\@setparms\@psfiga,}}
%
% Compute bb height and width
%
\newif\ifno@bb
\def\bb@missing{
	\if@verbose{
		\ps@typeout{psfig: searching \@p@sbbfile \space  for bounding box}
	}\fi
	\no@bbtrue
	\epsf@getbb{\@p@sbbfile}
        \ifno@bb \else \bb@cull\epsf@llx\epsf@lly\epsf@urx\epsf@ury\fi
}	
\def\bb@cull#1#2#3#4{
	\dimen100=#1 bp\edef\@p@sbbllx{\number\dimen100}
	\dimen100=#2 bp\edef\@p@sbblly{\number\dimen100}
	\dimen100=#3 bp\edef\@p@sbburx{\number\dimen100}
	\dimen100=#4 bp\edef\@p@sbbury{\number\dimen100}
	\no@bbfalse
}
% rotate point (#1,#2) about (0,0).
% The sine and cosine of the angle are already stored in \sine and
% \cosine.  The result is placed in (\p@intvaluex, \p@intvaluey).
\newdimen\p@intvaluex
\newdimen\p@intvaluey
\def\rotate@#1#2{{\dimen0=#1 sp\dimen1=#2 sp
%            	calculate x' = x \cos\theta - y \sin\theta
		  \global\p@intvaluex=\cosine\dimen0
		  \dimen3=\sine\dimen1
		  \global\advance\p@intvaluex by -\dimen3
% 		calculate y' = x \sin\theta + y \cos\theta
		  \global\p@intvaluey=\sine\dimen0
		  \dimen3=\cosine\dimen1
		  \global\advance\p@intvaluey by \dimen3
		  }}
\def\compute@bb{
		\no@bbfalse
		\if@bbllx \else \no@bbtrue \fi
		\if@bblly \else \no@bbtrue \fi
		\if@bburx \else \no@bbtrue \fi
		\if@bbury \else \no@bbtrue \fi
		\ifno@bb \bb@missing \fi
		\ifno@bb \ps@typeout{FATAL ERROR: no bb supplied or found}
			\no-bb-error
		\fi
		%
%\ps@typeout{BB: \@p@sbbllx, \@p@sbblly, \@p@sbburx, \@p@sbbury} 
%
% store height/width of original (unrotated) bounding box
		\count203=\@p@sbburx
		\count204=\@p@sbbury
		\advance\count203 by -\@p@sbbllx
		\advance\count204 by -\@p@sbblly
		\edef\ps@bbw{\number\count203}
		\edef\ps@bbh{\number\count204}
		%\ps@typeout{ psbbh = \ps@bbh, psbbw = \ps@bbw }
		\if@angle 
			\Sine{\@p@sangle}\Cosine{\@p@sangle}
	        	{\dimen100=\maxdimen\xdef\r@p@sbbllx{\number\dimen100}
					    \xdef\r@p@sbblly{\number\dimen100}
			                    \xdef\r@p@sbburx{-\number\dimen100}
					    \xdef\r@p@sbbury{-\number\dimen100}}
%
% Need to rotate all four points and take the X-Y extremes of the new
% points as the new bounding box.
                        \def\minmaxtest{
			   \ifnum\number\p@intvaluex<\r@p@sbbllx
			      \xdef\r@p@sbbllx{\number\p@intvaluex}\fi
			   \ifnum\number\p@intvaluex>\r@p@sbburx
			      \xdef\r@p@sbburx{\number\p@intvaluex}\fi
			   \ifnum\number\p@intvaluey<\r@p@sbblly
			      \xdef\r@p@sbblly{\number\p@intvaluey}\fi
			   \ifnum\number\p@intvaluey>\r@p@sbbury
			      \xdef\r@p@sbbury{\number\p@intvaluey}\fi
			   }
%			lower left
			\rotate@{\@p@sbbllx}{\@p@sbblly}
			\minmaxtest
%			upper left
			\rotate@{\@p@sbbllx}{\@p@sbbury}
			\minmaxtest
%			lower right
			\rotate@{\@p@sbburx}{\@p@sbblly}
			\minmaxtest
%			upper right
			\rotate@{\@p@sbburx}{\@p@sbbury}
			\minmaxtest
			\edef\@p@sbbllx{\r@p@sbbllx}\edef\@p@sbblly{\r@p@sbblly}
			\edef\@p@sbburx{\r@p@sbburx}\edef\@p@sbbury{\r@p@sbbury}
%\ps@typeout{rotated BB: \r@p@sbbllx, \r@p@sbblly, \r@p@sbburx, \r@p@sbbury}
		\fi
		\count203=\@p@sbburx
		\count204=\@p@sbbury
		\advance\count203 by -\@p@sbbllx
		\advance\count204 by -\@p@sbblly
		\edef\@bbw{\number\count203}
		\edef\@bbh{\number\count204}
		%\ps@typeout{ bbh = \@bbh, bbw = \@bbw }
}
%
% \in@hundreds performs #1 * (#2 / #3) correct to the hundreds,
%	then leaves the result in @result
%
\def\in@hundreds#1#2#3{\count240=#2 \count241=#3
		     \count100=\count240	% 100 is first digit #2/#3
		     \divide\count100 by \count241
		     \count101=\count100
		     \multiply\count101 by \count241
		     \advance\count240 by -\count101
		     \multiply\count240 by 10
		     \count101=\count240	%101 is second digit of #2/#3
		     \divide\count101 by \count241
		     \count102=\count101
		     \multiply\count102 by \count241
		     \advance\count240 by -\count102
		     \multiply\count240 by 10
		     \count102=\count240	% 102 is the third digit
		     \divide\count102 by \count241
		     \count200=#1\count205=0
		     \count201=\count200
			\multiply\count201 by \count100
		 	\advance\count205 by \count201
		     \count201=\count200
			\divide\count201 by 10
			\multiply\count201 by \count101
			\advance\count205 by \count201
			%
		     \count201=\count200
			\divide\count201 by 100
			\multiply\count201 by \count102
			\advance\count205 by \count201
			%
		     \edef\@result{\number\count205}
}
\def\compute@wfromh{
		% computing : width = height * (bbw / bbh)
		\in@hundreds{\@p@sheight}{\@bbw}{\@bbh}
		%\ps@typeout{ \@p@sheight * \@bbw / \@bbh, = \@result }
		\edef\@p@swidth{\@result}
		%\ps@typeout{w from h: width is \@p@swidth}
}
\def\compute@hfromw{
		% computing : height = width * (bbh / bbw)
	        \in@hundreds{\@p@swidth}{\@bbh}{\@bbw}
		%\ps@typeout{ \@p@swidth * \@bbh / \@bbw = \@result }
		\edef\@p@sheight{\@result}
		%\ps@typeout{h from w : height is \@p@sheight}
}
\def\compute@handw{
		\if@height 
			\if@width
			\else
				\compute@wfromh
			\fi
		\else 
			\if@width
				\compute@hfromw
			\else
				\edef\@p@sheight{\@bbh}
				\edef\@p@swidth{\@bbw}
			\fi
		\fi
}
\def\compute@resv{
		\if@rheight \else \edef\@p@srheight{\@p@sheight} \fi
		\if@rwidth \else \edef\@p@srwidth{\@p@swidth} \fi
		%\ps@typeout{rheight = \@p@srheight, rwidth = \@p@srwidth}
}
%		
% Compute any missing values
\def\compute@sizes{
	\compute@bb
	\if@scalefirst\if@angle
% at this point the bounding box has been adjsuted correctly for
% rotation.  PSFIG does all of its scaling using \@bbh and \@bbw.  If
% a width= or height= was specified along with \psscalefirst, then the
% width=/height= value needs to be adjusted to match the new (rotated)
% bounding box size (specifed in \@bbw and \@bbh).
%    \ps@bbw       width=
%    -------  =  ---------- 
%    \@bbw       new width=
% so `new width=' = (width= * \@bbw) / \ps@bbw; where \ps@bbw is the
% width of the original (unrotated) bounding box.
	\if@width
	   \in@hundreds{\@p@swidth}{\@bbw}{\ps@bbw}
	   \edef\@p@swidth{\@result}
	\fi
	\if@height
	   \in@hundreds{\@p@sheight}{\@bbh}{\ps@bbh}
	   \edef\@p@sheight{\@result}
	\fi
	\fi\fi
	\compute@handw
	\compute@resv}
%
%
%
\def\OzTeXSpecials{
	\special{empty.ps /@isp {true} def}
	\special{empty.ps \@p@swidth \space \@p@sheight \space
			\@p@sbbllx \space \@p@sbblly \space
			\@p@sbburx \space \@p@sbbury \space
			startTexFig \space }
	\if@clip{
		\if@verbose{
			\ps@typeout{(clip)}
		}\fi
		\special{empty.ps doclip \space }
	}\fi
	\if@angle{
		\if@verbose{
			\ps@typeout{(rotate)}
		}\fi
		\special {empty.ps \@p@sangle \space rotate \space} 
	}\fi
	\if@prologfile
	    \special{\@prologfileval \space } \fi
	\if@decmpr{
		\if@verbose{
			\ps@typeout{psfig: Compression not available
			in OzTeX version \space }
		}\fi
	}\else{
		\if@verbose{
			\ps@typeout{psfig: including \@p@sfile \space }
		}\fi
		\special{epsf=\ps@predir\@p@sfile \space }
	}\fi
	\if@postlogfile
	    \special{\@postlogfileval \space } \fi
	\special{empty.ps /@isp {false} def}
}
\def\DvipsSpecials{
	%
	\special{ps::[begin] 	\@p@swidth \space \@p@sheight \space
			\@p@sbbllx \space \@p@sbblly \space
			\@p@sbburx \space \@p@sbbury \space
			startTexFig \space }
	\if@clip{
		\if@verbose{
			\ps@typeout{(clip)}
		}\fi
		\special{ps:: doclip \space }
	}\fi
	\if@angle
		\if@verbose{
			\ps@typeout{(clip)}
		}\fi
		\special {ps:: \@p@sangle \space rotate \space} 
	\fi
	\if@prologfile
	    \special{ps: plotfile \@prologfileval \space } \fi
	\if@decmpr{
		\openin1=\ps@predir\@p@sfile.gz
		\ifeof1
		        \closein1
		        % failed, supposed to be a *.Z file
			\if@verbose{
				\ps@typeout{psfig: including \@p@sfile.Z \space }
			}\fi
			\special{ps: plotfile "`zcat \@p@sfile.Z" \space }
		\else
                        \closein1
			% found .gz file
			\if@verbose{
				\ps@typeout{psfig: including \@p@sfile.gz \space }
			}\fi
			\special{ps: plotfile "`gunzip -c \@p@sfile.gz" \space }
		\fi
	}\else{
		\if@verbose{
			\ps@typeout{psfig: including \@p@sfile \space }
		}\fi
		\special{ps: plotfile \@p@sfile \space }
	}\fi
	\if@postlogfile
	    \special{ps: plotfile \@postlogfileval \space } \fi
	\special{ps::[end] endTexFig \space }
}
%
% \psfig
% usage : \psfig{file=, height=, width=, bbllx=, bblly=, bburx=, bbury=,
%			rheight=, rwidth=, clip=}
%
% "clip=" is a switch and takes no value, but the `=' must be present.
\def\psfig#1{\vbox {
	% do a zero width hard space so that a single
	% \psfig in a centering enviornment will behave nicely
	%{\setbox0=\hbox{\ }\ \hskip-\wd0}
	%
	\ps@init@parms
	\parse@ps@parms{#1}
	\compute@sizes
	%
	\ifnum\@p@scost<\@psdraft{
		\PsfigSpecials 
		% Create the vbox to reserve the space for the figure.
		\vbox to \@p@srheight sp{
		% 1/92 TJD Changed from "true sp" to "sp" for magnification.
			\hbox to \@p@srwidth sp{
				\hss
			}
		\vss
		}
	}\else{
		% draft figure, just reserve the space and print the
		% path name.
		\if@draftbox{		
			% Verbose draft: print file name in box
			% 10/93 TJD changed to fbox from frame
			\hbox{\fbox{\vbox to \@p@srheight sp{
			\vss
			\hbox to \@p@srwidth sp{ \hss 
			        % 10/93 TJD deleted to avoid ``_'' problems
				% \@p@sfile
			 \hss }
			\vss
			}}}
		}\else{
			% Non-verbose draft
			\vbox to \@p@srheight sp{
			\vss
			\hbox to \@p@srwidth sp{\hss}
			\vss
			}
		}\fi	



	}\fi
}}
\psfigRestoreAt
\setDriver
\let\@=\LaTeXAtSign




symbols.tex
% USEFUL SYMBOLS

\def\ie{\mbox{\'{\i}}}

% NOMS DE SOURCES

\def\unedzs{1 \mbox{E } 1207.4-5209}
\def\annihilateur{1 \mbox{E } 1740.7-2942}
\def\unedhqu{1 \mbox{E } 1841-045}
\def\azsv{\mbox{A}0620-00}
\def\cicam{\mbox{CI Cam}}
\def\cirxu{\mbox{Circinus X-1}}
\def\cygxu{\mbox{Cygnus X-1}}
\def\cygxt{\mbox{Cygnus X-3}}
\def\grb{\mbox{GRB} 990712}
\def\gro{\mbox{GRO J} 1655-40}
\def\grs{\mbox{GRS } 1915+105}
\def\grsdstq{\mbox{GRS } 1734-292}
\def\grsdstn{\mbox{GRS } 1739-278}
\def\grsdsch{\mbox{GRS } 1758-258}
\def\gx{\mbox{GX } 339-4}
\def\gxtcq{\mbox{GX } 354-0}
\def\irasnord{\mbox{IRAS } 19124+1106}
\def\irassud{\mbox{IRAS } 19132+1035}
\def\ksdsvq{\mbox{KS } 1724-356}
\def\ksdstu{\mbox{KS } 1731-260}
\def\lmcxu{\mbox{LMC } X-1}
\def\lmcxt{\mbox{LMC } X-3}
\def\novmus{\mbox{Nova Muscae 1991}}
\def\novoph{\mbox{Nova Ophiuchi 1993}}
\def\qu{\mbox{4U } 1630-47}
\def\saxjdsqs{\mbox{SAX J1747.0-2853}}
\def\saxjdhzh{\mbox{SAX J1808.4-3658}}
\def\saxjdhdn{\mbox{SAX J1819.3-2525}}
\def\scoxu{\mbox{Sco X-1}}
\def\seyfert{\mbox{Seyfert}}
\def\sgrzcvc{\mbox{SGR } 0525-66}
\def\sgrsvs{\mbox{SGR } 1627-41}
\def\sgr{\mbox{SGR } 1806-20}
\def\sgrdnc{\mbox{SGR } 1900+14}
\def\slx{\mbox{SLX } 1735-269}
\def\smcxu{\mbox{SMC X-1}}
\def\snr{\mbox{SNR G } 45.7-0.4}
\def\ss{\mbox{SS } 433}
\def\terzanu{\mbox{Terzan\,\,}1}
\def\terzanun{\mbox{Terzan\,\,}1}
\def\vqcqc{\mbox{V} 404 \mbox{Cyg}}
\def\wc{\mbox{W } 50}
\def\xtejzqvu{\mbox{XTE J} 0421+560}
\def\xtejodh{\mbox{XTE J} 1118+480}
\def\xtejqcq{\mbox{XTE J} 1550-564}
\def\xtejdsqh{\mbox{XTE J}1748-288}
\def\xtejdscc{\mbox{XTE J} 1755-324}
\def\xtejdhcn{\mbox{XTE J} 1859+226}

% UNITES

\def\angstrom{\mbox{ \scriptsize{A} \vspace*{1.cm}\hspace{-2.9mm}}^{\circ}}
\def\arcsecdeux{\mbox{ arc.s}^{2}}
\def\cmmoinsdeux{\mbox{ cm}^{-2}}
\def\cmmoinstrois{\mbox{ cm}^{-3}}
\def\cm{\mbox{ cm}}
\def\metre{\mbox{ m}}
\def\kg{\mbox{ kg}}
\def\micrometre{\mbox{ } \mu \mbox{m}}
\def\microns{\mbox{ } \mu \mbox{m}}
\def\hz{\mbox{ Hz}}
\def\msmoinsun{\mbox{ m.s}^{-1}}
\def\msmoinsdeux{\mbox{ m.s}^{-2}}
\def\kms{\mbox{ km\,s}^{-1}}
\def\pc{\mbox{ pc}}
\def\kpc{\mbox{ kpc}}
\def\Mpc{\mbox{ Mpc}}
\def\kmh{\mbox{ km\,h}^{-1}}
\def\Kkms{\mbox{ K\,km\,s}^{-1}}
\def\Msol{\mbox{ }M_{\odot}}
\def\Lsol{\mbox{ }L_{\odot}}
\def\mag{\mbox{ magnitude}}
\def\mags{\mbox{ magnitudes}}
\def\mJy{\mbox{ mJy}}
\def\Jy{\mbox{ Jy}}
\def\mT{\mbox{ mT}}
\def\rad{\mbox{ rad}}
\def\G{\mbox{ G}}
\def\J{\mbox{ J}}
\def\K{\mbox{ K}}
\def\sparan{\mbox{ s an}^{-1}}
\def\paran{\mbox{ an}^{-1}}
\def\jours{\mbox{ jours}}
\def\JparK{\mbox{ J K}^{-1}}
\def\NAmoinsdeux{\mbox{ N A}^{-2}}
\def\WattCmMoinsDeuxMuMoinsUn{\mbox{ W cm}^{-2}\mu \mbox{m}^{-1}}
\def\Wattmetremoinsdeux{\mbox{ W m}^{-2}}
\def\WparHz{\mbox{ W Hz}^{-1}}
\def\erg{\mbox{ erg}}
\def\ergpars{\mbox{ erg\,s}^{-1}}
\def\ergs{\mbox{ erg\,s}^{-1}}
\def\ergcms{\mbox{ erg s}^{-1} \mbox{cm}^{-2}}
\def\ergcmsarcmin{\mbox{ erg cm}^{-2} \mbox{s}^{-1} \mbox{arcmin}^{-2}}
\def\ergcmsang{\mbox{ erg cm}^{-2} \mbox{s}^{-1} \mbox{A \hspace{-6mm}}^{\circ}}
\def\arcminmoinsdeux{\mbox{arcmin}^{-2}}
\def\keV{\mbox{ keV}}
\def\W{\mbox{ W}}
\def\countss{\mbox{ counts s}^{-1}}
\def\coupss{\mbox{ coups s}^{-1}}
\def\cmmoinstrois{\mbox{ cm}^{-3}}
\def\masparan{\times 10^{-3 \, \prime \prime} \mbox{ an}^{-1}}
\def\mJyparbeam{\mbox{ mJy\,beam}^{-1}}
\def\janskyparbeam{\mbox{ Jansky\,faisceau}^{-1}}
\def\gcmcube{\mbox{ g cm}^{-3}}

% ANGLES

\def\deg{^{\circ}}
\def\degp{{\rlap.}^{\circ}}
\def\amin{^\prime}
\def\aminp{{\rlap.}^{\prime}}
\def\asec{^{\prime \prime}}
\def\asecp{{\rlap.}^{\prime \prime}}

\def\heu{^{h}}
\def\heup{{\rlap.}^{h}}
\def\hmin{^{m}}
\def\hminp{{\rlap.}^{m}}
\def\hsec{^{s}}
\def\hsecp{{\rlap.}^{s}}

% MOLECULES ET TRANSITIONS

\def\douzecoabb{^{12} \mbox{CO}}
\def\treizecoabb{^{13} \mbox{CO}}
\def\hcoabb{\mbox{H}^{13}\mbox{CO}^{+}}
\def\siodeuxabb{\mbox{SiO}_{2-1}}
\def\siotroisabb{\mbox{SiO}_{3-2}}
\def\siocinqabb{\mbox{SiO}_{5-4}}
\def\csabb{\mbox{CS}}

\def\douzecounzero{^{12} \mbox{CO } (\mbox{J} = 1 - 0)}
\def\douzecodeuxun{^{12} \mbox{CO } (\mbox{J} = 2 - 1)}
\def\treizecodeuxun{^{13} \mbox{CO } (\mbox{J} = 2 - 1)}
\def\treizecounzero{^{13} \mbox{CO } (\mbox{J} = 1 - 0)}
\def\hcoplus{\mbox{H}^{13}\mbox{CO}^{+ }(\mbox{J} = 1 - 0)}
\def\siodeuxun{\mbox{SiO } (\mbox{J} = 2 - 1, v = 0)}
\def\siotroisdeux{\mbox{SiO } (\mbox{J} = 3 - 2, v = 0)}
\def\siocinqquatre{\mbox{SiO } (\mbox{J} = 5 - 4, v = 0)}
\def\csdeuxun{\mbox{CS } (\mbox{J} = 2 - 1)}
\def\hdeux{\mbox{H}_{2}}

\def\Ta{\mbox{T}_{A}^{*}}

% ABBREVATIONS

\def\Av{A_{\rm v}}
\def\plusoumoins{\, \pm \,}
\def\pom{\, \pm \,}
\def\cad{\mbox{c'est-\`a-dire}}
\def\taf{\mbox{tout � fait}}
\def\foot{\footnotemark\footnotetext}
\def\hdeuxromain{\mbox{H\,{\sc ii}}}
\def\nh{N \mbox{(H)}}
\def\rg{r_{\scriptsize g}}
\def\ltsima{\; \buildrel < \over \sim \;}
\def\simlt{\lower.5ex\hbox{\ltsima}}            % < over MMM
\def\gtsima{\; \buildrel > \over \sim \;}
\def\simgt{\lower.5ex\hbox{\gtsima}}            % > over MMM

% NOMS

\def\M{\mbox{Mirabel}}
\def\R{\mbox{Rodr\'{\i}guez}}

integral_sax.bbl
\begin{thebibliography}{26}
\expandafter\ifx\csname natexlab\endcsname\relax\def\natexlab#1{#1}\fi
\expandafter\ifx\csname url\endcsname\relax
  \def\url#1{{\tt #1}}\fi
\expandafter\ifx\csname urlprefix\endcsname\relax\def\urlprefix{URL }\fi

\bibitem[{{Ayani} et~al.(1999){Ayani}, {Peiris}, \& {Clarke
  Institute}}]{ayani:1999}
{Ayani} K., {Peiris} T.C., {Clarke Institute} C., Sep. 1999, {IAU Circ.}, 7254,
  1+

\bibitem[{{Bohlin} et~al.(1978){Bohlin}, {Savage}, \& {Drake}}]{bohlin:1978}
{Bohlin} R.C., {Savage} B.D., {Drake} J.F., Aug. 1978, {Astrophys. J.}, 224,
  132

\bibitem[{{Charles} et~al.(1999){Charles}, {Shahbaz}, \&
  {Geballe}}]{charles:1999a}
{Charles} P.A., {Shahbaz} T., {Geballe} T., Oct. 1999, {IAU Circ.}, 7267, 2+

\bibitem[{{Chaty} et~al.(2001){Chaty}, {Rodr\'{\i}guez}, {Mirabel}
  et~al.}]{chaty:2001}
{Chaty} S., {Rodr\'{\i}guez} L.F., {Mirabel} I.F., et~al., 2001, {Astron.
  Astrophys.}, 366, 1041

\bibitem[{{Hjellming} et~al.(1999{\natexlab{a}}){Hjellming}, {Rupen}, \&
  {Mioduszewski}}]{hjellming:1999a}
{Hjellming} R.M., {Rupen} M.P., {Mioduszewski} A.J., Sep. 1999{\natexlab{a}},
  {IAU Circ.}, 7254, 2+

\bibitem[{{Hjellming} et~al.(1999{\natexlab{b}}){Hjellming}, {Rupen}, \&
  {Mioduszewski}}]{hjellming:1999b}
{Hjellming} R.M., {Rupen} M.P., {Mioduszewski} A.J., Sep. 1999{\natexlab{b}},
  {IAU Circ.}, 7265, 2+

\bibitem[{{Hjellming} et~al.(2000){Hjellming}, {Rupen}, {Hunstead}
  et~al.}]{hjellming:2000}
{Hjellming} R.M., {Rupen} M.P., {Hunstead} R.W., et~al., Dec. 2000, {Astrophys.
  J.}, 544, 977

\bibitem[{{in't Zand} et~al.(1999){in't Zand}, {Heise}, {Bazzano}
  et~al.}]{in'tzand:1999}
{in't Zand} J., {Heise} J., {Bazzano} A., et~al., 1999, {IAU Circ.}, 7119

\bibitem[{{in't Zand} et~al.(2000){in't Zand}, {Kuulkers}, {Bazzano}
  et~al.}]{in'tzand:2000}
{in't Zand} J.J.M., {Kuulkers} E., {Bazzano} A., et~al., May 2000, {Astron.
  Astrophys.}, 357, 520

\bibitem[{{Kato} et~al.(1999){Kato}, {Uemura}, {Stubbings}, {Watanabe}, \&
  {Monard}}]{kato:1999}
{Kato} T., {Uemura} M., {Stubbings} R., {Watanabe} T., {Monard} B., Oct. 1999,
  Informational Bulletin on Variable Stars, 4777, 1+

\bibitem[{{Kazarovets} et~al.(2000){Kazarovets}, {Samus}, \&
  {Durlevich}}]{kazarovets:2000}
{Kazarovets} E.V., {Samus} N.N., {Durlevich} O.V., Mar. 2000, Informational
  Bulletin on Variable Stars, 4870, 1+

\bibitem[{{Kolb} et~al.(1997){Kolb}, {King}, {Ritter}, \& {Frank}}]{kolb:1997}
{Kolb} U., {King} A., {Ritter} H., {Frank} J., 1997, {Astrophys. J.}, 485, L33

\bibitem[{Markwardt et~al.(1999)Markwardt, Swank, \&
  Marshall}]{markwardt:1999a}
Markwardt C., Swank J., Marshall F., 1999, {IAU Circ.}, 7120

\bibitem[{{Mart\'{\i}} et~al.(2001){Mart\'{\i}}, {Zamanov}, {Paredes}, \&
  {Rib\'o}}]{marti:2001}
{Mart\'{\i}} J., {Zamanov} R., {Paredes} J.M., {Rib\'o} M., 2001, Informational
  Bulletin on Variable Stars, submitted

\bibitem[{{Mirabel} \& {Rodr\'{\i}guez}(1999)}]{mirabel:1999}
{Mirabel} I., {Rodr\'{\i}guez} L., 1999, {Annu. Rev. Astron. Astrophys.}, 37,
  409

\bibitem[{{Mirabel} et~al.(1996){Mirabel}, {Rodr\'{\i}guez}, {Chaty}
  et~al.}]{mirabel:1996a}
{Mirabel} I.F., {Rodr\'{\i}guez} L.F., {Chaty} S., et~al., 1996, {Astrophys.
  J.}, 472, L111

\bibitem[{{Munari} \& {Zwitter}(1997)}]{munari:1997}
{Munari} U., {Zwitter} T., Feb. 1997, {Astron. Astrophys.}, 318, 269

\bibitem[{{Orosz} et~al.(2000{\natexlab{a}}){Orosz}, {Kuulkers}, {van der Klis}
  et~al.}]{orosz:2000}
{Orosz} J.A., {Kuulkers} E., {van der Klis} M., et~al., Jun.
  2000{\natexlab{a}}, {IAU Circ.}, 7440, 1+

\bibitem[{{Orosz} et~al.(2000{\natexlab{b}}){Orosz}, {Kuulkers}, {van der Klis}
  et~al.}]{orosz:2000a}
{Orosz} J.A., {Kuulkers} E., {van der Klis} M., et~al., Dec.
  2000{\natexlab{b}}, In: American Astronomical Society Meeting, vol. 197,
  8320+

\bibitem[{{Ruelas-Mayorga}(1991)}]{ruelas-mayorga:1991}
{Ruelas-Mayorga} R.A., Apr. 1991, Revista Mexicana de Astronomia y Astrofisica,
  22, 27

\bibitem[{{Samus} et~al.(1999){Samus}, {Hazen}, {Williams} et~al.}]{samus:1999}
{Samus} N.N., {Hazen} M., {Williams} D., et~al., Oct. 1999, {IAU Circ.}, 7277,
  1+

\bibitem[{Smith et~al.(1999)Smith, Levine, \& Morgan}]{smith:1999}
Smith D., Levine A., Morgan E., 1999, {IAU Circ.}, 7253

\bibitem[{Stubbings(1999)}]{stubbings:1999}
Stubbings R., 1999, {IAU Circ.}, 7253

\bibitem[{{Watanabe}(1999)}]{watanabe:1999}
{Watanabe} T., 1999, VSOLJ Variable Star Bulletin, 34, 3

\bibitem[{{Wijnands} \& {van der Klis}(2000)}]{wijnands:2000}
{Wijnands} R., {van der Klis} M., Jan. 2000, {Astrophys. J.}, 528, L93

\bibitem[{{Williams}(1999)}]{williams:1999}
{Williams} G.V., Sep. 1999, {IAU Circ.}, 7253, 3+

\end{thebibliography}
