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 IAUS275
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%=20iaus2esa.tex=20--=20sample=20pages=20for=20Proceedings=20IAU=20=
Symposium=20document=20class=0D=0A%=20(based=20on=20v1.0=20cca2esam.tex)=0D=
=0A%=20v1.04=20released=2017=20May=202004=20by=20TechBooks=0D=0A%%=20=
small=20changes=20and=20additions=20made=20by=20KAvdH/IAU=204=20June=20=
2004=0D=0A%=20Copyright=20(2004)=20International=20Astronomical=20Union=0D=
=0A=0D=0A%convert=20sgr-mhdmodels+vlbi.png=20sgr-mhdmodels+vlbi.jpg=20=0D=
=0A%~/bin/jpeg2ps=20-o=20sgr-mhdmodels+vlbi.ps=20sgr-mhdmodels+vlbi.jpg=20=
=0D=0A=0D=0A=0D=0A%tar=20-cvzf=20falcke.tgz=20iaus275.pdf=20iaus.cls=20=
iaus275.bbl=20iaus275.tex=20iaus.cls=20astro.sty=20aa.bst=20=
sgr-lg-intrinsicsize-vs-lambda.eps=20sgr-lg-size-vs-lambda.eps=20=
gammie3DMHDmodel_a=3D0.9.ps=20mmvlbiarray.ps=20sgr-mhdmodels+vlbi.ps=20=
sgr-spectrum.ps=0D=0A%Sent=20to=20=20jaas@iar-conicet.gov.ar=0D=0A=0D=0A=
%tar=20-cvzf=20falcke.tgz=20iaus.cls=20iaus275.bbl=20iaus275.tex=20=
iaus.cls=20astro.sty=20aa.bst=20sgr-lg-intrinsicsize-vs-lambda.eps=20=
sgr-lg-size-vs-lambda.eps=20gammie3DMHDmodel_a=3D0.9.ps=20mmvlbiarray.ps=20=
sgr-mhdmodels+vlbi.ps=20sgr-spectrum.ps=0D=0A%for=20astro-ph=0D=0A=0D=0A=
\NeedsTeXFormat{LaTeX2e}=0D=0A=0D=0A\documentclass{iaus}=0D=0A=
\usepackage{graphicx,natbib,astro}=0D=0A\topmargin3.0cm=0D=0A=
\title[Galactic=20Center=20Jet]=20%%=20give=20here=20short=20title=20%%=0D=
=0A{The=20Jet=20in=20the=20Galactic=20Center:=20An=20Ideal=20Laboratory=20=
for=0D=0A=20=20Magnetohydrodynamics=20and=20General=20Relativity}=0D=0A=0D=
=0A\author[Falcke=20et=20al.]=20=20=20%%=20give=20here=20short=20author=20=
list=20%%=0D=0A{Heino=20Falcke$^{1,2}$,=20%\and=20=0D=0ASera=20=
Markoff$^{3}$,=20%\and=0D=0AGeoffrey=20C.=20Bower$^{4}$,=20%\and=0D=0A=
Charles=20F.=20Gammie$^{5,6}$,=20%\and=0D=0AMonika=20Mo\'scibrodzka$^5$,=20=
\and=0D=0ADipankar=20Maitra$^7$=20=0D=0A}=0D=0A=0D=0A%%=20=20=
\thanks{Present=20address:=20Fluid=20Mech=20Inc.,=2024=20The=20Street,=20=
Lagos,=20Nigeria.},=0D=0A=0D=0A\affiliation{$^1$Department=20of=0D=0A=20=20=
Astrophysics,=20Institute=20for=20Mathematics,=20Astrophysics=20and=20=
Particle=0D=0A=20=20Physics=20(IMAPP),=20Radboud=20University,=20=
Nijmegen,=20The=20Netherlands=20\\[\affilskip]=20=0D=0A$^2$ASTRON,=20=
Oude=0D=0A=20=20Hoogeveensedijk=204,=207991=20PD=20Dwingeloo,=20The=20=
Netherlands=20\\[\affilskip]=0D=0A$^3$Astronomical=20Institute=20``Anton=20=
Pannekoek'',=20University=20of=0D=0A=20=20Amsterdam,=20The=20Netherlands=20=
\\[\affilskip]=0D=0A$^4$=20Astronomy=20Department=20\&=20Radio=20=
Astronomy=20Lab,=20UC=20Berkeley,=20USA\\[\affilskip]=0D=0A=
$^5$Department=20of=20Physics,=20University=20of=20Illinois,=0D=0A=
Urbana,=20Illinois,=20USA\\[\affilskip]=0D=0A$^6$Astronomy=20Department,=20=
University=20of=20Illinois,=20Urbana,=20Illinois,=20USA=20\\[\affilskip]=0D=
=0A$^7$Department=20of=20Astronomy,=20University=20of=20Michigan,=20Ann=20=
Arbor,=0D=0AMichigan,=20USA=20=0D=0A}=0D=0A=0D=0A\pubyear{2010}=0D=0A=
\volume{275}=20=20%%=20insert=20here=20IAU=20Symposium=20No.=0D=0A=
\pagerange{1--9}=0D=0A%=20\date{??=20and=20in=20revised=20form=20??}=0D=0A=
\setcounter{page}{1}=0D=0A\jname{Jets=20at=20all=20Scales}=0D=0A=
\editors{G.E.=20Romero,=20R.A.=20Sunyaev=20\&=20T.=20Belloni,=20eds.}=0D=0A=
\begin{document}=0D=0A=0D=0A\maketitle=0D=0A=0D=0A\begin{abstract}=0D=0A=20=
=20Of=20all=20possible=20black=20hole=20sources,=20the=20event=20horizon=20=
of=20the=0D=0A=20=20Galactic=20Center=20black=20hole,=20Sgr=20A*,=20=
subtends=20the=20largest=20angular=0D=0A=20=20scale=20on=20the=20sky.=20=
It=20is=20therefore=20a=20prime=20candidate=20to=20study=20and=0D=0A=20=20=
image=20plasma=20processes=20in=20strong=20gravity=20and=20it=20even=20=
allows=20imaging=0D=0A=20=20of=20the=20shadow=20cast=20by=20the=20event=20=
horizon.=20Recent=20mm-wave=20VLBI=20and=0D=0A=20=20radio=20timing=20=
observations=20as=20well=20as=20numerical=20GRMHD=20simulations=20now=0D=0A=
=20=20have=20provided=20several=20breakthroughs=20that=20put=20Sgr=20A*=20=
back=20into=20the=0D=0A=20=20focus.=20Firstly,=20VLBI=20observations=20=
have=20now=20measured=20the=20intrinsic=0D=0A=20=20size=20of=20Sgr=20A*=20=
at=20multiple=20frequencies,=20where=20the=20highest=20frequency=0D=0A=20=
=20measurements=20have=20approached=20the=20scale=20of=20the=20black=20=
hole=0D=0A=20=20shadow.=20Moreover,=20measurements=20of=20the=20radio=20=
variability=20show=20a=20clear=0D=0A=20=20time=20lag=20between=2022=20=
GHz=20and=2043=20GHz.=20The=20combination=20of=20size=20and=0D=0A=20=20=
timing=20measurements,=20allows=20one=20to=20actually=20measure=20the=20=
flow=20speed=0D=0A=20=20and=20direction=20of=20magnetized=20plasma=20at=20=
some=20tens=20of=20Schwarzschild=0D=0A=20=20radii.=20=20This=20data=20=
strongly=20support=20a=20moderately=20relativistic=0D=0A=20=20outflow,=20=
consistent=20with=20an=20accelerating=20jet=20model.=20This=20is=20=
compared=0D=0A=20=20to=20recent=20GRMHD=20simulation=20that=20show=20the=20=
presence=20of=20a=20moderately=0D=0A=20=20relativistic=20outflow=20=
coupled=20to=20an=20accretion=20flow=20Sgr=20A*.=20Further=0D=0A=20=20=
VLBI=20and=20timing=20observations=20coupled=20to=20simulations=20have=20=
the=0D=0A=20=20potential=20to=20map=20out=20the=20velocity=20profile=20=
from=205-40=20Schwarzschild=0D=0A=20=20radii=20and=20to=20provide=20a=20=
first=20glimpse=20at=20the=20appearance=20of=20a=20jet-disk=0D=0A=20=20=
system=20near=20the=20event=20horizon.=20Future=20submm-VLBI=20=
experiments=20would=0D=0A=20=20even=20be=20able=20to=20directly=20image=20=
those=20processes=20in=20strong=20gravity=20and=0D=0A=20=20directly=20=
confirm=20the=20presence=20of=20an=20event=20horizon.=20=0D=0A=
\keywords{accretion,=20black=20hole=20physics,=20gravitation,=20MHD,=20=
relativity,=0D=0A=20=20instrumentation:=20interferometers,=20=20=
instrumentation:=20high=20angular=0D=0A=20=20resolution,=20Galaxy:=20=
center,=20Galaxy:=20nucleus,=20galaxies:=20jets,=20quasars:=20general}=0D=
=0A%%=20add=20here=20a=20maximum=20of=2010=20keywords,=20to=20be=20taken=20=
form=20the=20file=20<Keywords.txt>=0D=0A\end{abstract}=0D=0A=0D=0A=
\firstsection=20%=20if=20your=20document=20starts=20with=20a=20section,=0D=
=0A=20=20=20=20=20=20=20=20=20=20=20=20=20=20%=20remove=20some=20space=20=
above=20using=20this=20command.=0D=0A\section{Introduction}=0D=0ABased=20=
on=20an=20analogy=20to=20other=20active=20galactic=20nuclei=20(AGN)=0D=0A=
\cite{Lynden-BellRees1971}=20proposed=20to=20look=20for=20a=20compact=20=
radio=20source=0D=0Ain=20the=20center=20of=20our=20own=20Milky=20Way,=20=
which=20was=20then=20discovered=20by=0D=0A\cite{BalickBrown1974}=20only=20=
a=20little=20later=20with=20the=20NRAO=0D=0Ainterferometer=20at=20Green=20=
Bank=20--=20barely=20beating=20the=20team=20at=20Westerbork=0D=0A=
\citep{EkersGossSchwarz1975}.=20This=20``compact=20radio=20source=20in=20=
the=0D=0AGalactic=20Center''=20became=20later=20known=20as=20=
``Sagittarius=20A*''=20(Sgr=20A*)=0D=0Aand=20by=20now=20is=20the=20best=20=
constrained=20super-massive=20black=20hole=20candidate=0D=0Awe=20know=20=
of=20to=20date=20\citep[see][for=20a=0D=0A=
review]{MeliaFalcke2001,GenzelEisenhauerGillessen2010},=20with=20a=20=
mass=20of=0D=0A$4\times10^6=20M_\odot$=20measured=20from=20stellar=20=
orbits=0D=0A=
\citep{SchodelOttGenzel2002,GhezSalimWeinberg2008,GillessenEisenhauerFritz=
2009}.=0D=0ASgr~A*=20serves=20as=20an=20excellent=20example=20to=20=
understand=20black=20holes=20(and=0D=0Acompact=20radio=20cores)=20at=20=
very=20low=20accretion=20rates=20and=20is=20a=20potentially=0D=0A=
exciting=20laboratory=20for=20the=20study=20of=20General=20Relativity=20=
(GR)=0D=0Aitself.=20In=20fact,=20\cite{FalckeMeliaAgol2000}=20argued=20=
that,=20what=20they=0D=0Acalled=20the=20``shadow=20of=20the=20black=20=
hole=20event=20horizon''=20could=20reasonably=0D=0Abe=20detected=20with=20=
mm-wave=20very=20long=20baseline=20interferometry=20(VLBI)=20in=0D=0A=
this=20source=20and=20many=20papers=20have=20since=20illuminated=20=
various=20general=0D=0Arelativistic=20effects=20that=20could=20be=20=
tested=20in=20this=20way=0D=0A=
\citep{BroderickLoeb2006,FishDoelemanBroderick2009,HarkoLobo2009,YuanCaoHu=
ang2009,JohannsenPsaltis2010,DexterAgolFragile2010}.=0D=0A=0D=0AHowever,=20=
ever=20since=20its=20discovery,=20a=20discussion=20raged=20about=20the=20=
exact=0D=0Anature=20of=20its=20emission=20processes=20and=20the=20region=20=
where=20the=20observable=0D=0Aradiation=20is=20emitted.=20Already=20=
\cite{ReynoldsMcKee1980}=20suggested=20an=0D=0Aorigin=20of=20the=20radio=20=
emission=20in=20a=20jet=20or=20wind=20from=20a=20stellar-sized=0D=0A=
object.=20Indeed,=20the=20properties=20of=20Sgr=20A*=20resemble=20those=20=
of=0D=0Aflat-spectrum=20compact=20radio=20cores=20in=20quasars=20(later=20=
also=20found=20in=0D=0AX-ray=20binaries),=20which=20were=20explained=20=
by=20\cite{BlandfordKonigl1979}=20as=0D=0Athe=20$\tau$=3D1=20surfaces=20=
(optical=20depth=20becomes=20unity)=20of=20powerful=20=0D=0Arelativistic=20=
jets.=20This=20issue=20was=20revisited=20by=0D=0A=
\cite{FalckeMannheimBiermann1993,FalckeMarkoff2000}=20who=20explained=0D=0A=
spectrum=20and=20size=20of=20Sgr=20A*=20as=20a=20scaled-down=20quasar=20=
jet=20from=20an=20``AGN=0D=0Aon=20a=20starvation=20diet'',=20i.e.=20a=20=
supermassive=20black=20hole=20with=20very=20low=0D=0Aaccretion=20rate=20=
($\dot=20M<10^{-7}=20M_\odot/{\rm=20yr}$).=20This=20semi-analytic=0D=0A=
approach=20was=20based=20based=20upon=20a=20modified=20=
Blandford-K\"onigl=20model=0D=0A\cite[][taking=20the=20longitudinal=20=
pressure=20gradient=20into=0D=0Aaccount]{Falcke1996a}=20and=20the=20=
jet-disk=20symbiosis=20ansatz=0D=0A=
\citep{FalckeBiermann1995,FalckeBiermann1999},=20which=20introduced=20a=20=
very=0D=0Asimple,=20yet=20until=20to=20day=20very=20effective=20linear=20=
scaling=20between=0D=0Ajet-power=20and=20accretion=20disk=20rate=20for=20=
black=20holes=20$Q_{\rm=20jet}=3Dq_{\rm=0D=0A=20=20j}\dot=20M_{\rm=20=
disk}$,=20where=20$q_{\rm=20j}\sim3-10\%.$=20Based=20on=20the=0D=0A=
jet-disk=20symbiosis=20model,=20a=20number=20of=20concrete=20predictions=20=
were=20made=0D=0A\citep{Falcke1999b}=20that=20all=20have=20stood=20the=20=
test=20of=20time.=0D=0A=0D=0AAlternatively,=20it=20was=20proposed=20that=20=
the=20radio=20emission=20--=20and=0D=0Asubsequently=20the=20emission=20=
at=20other=20wavelengths=20--=20was=20produced=20in=20the=0D=0Aaccretion=20=
flow=20itself.=20While=20standard=20optically=20thick,=20geometrically=0D=
=0Athin=20accretion=20models=20started=20to=20fail=20in=20explaining=20=
the=20low=20infrared=0D=0Aflux=20of=20Sgr=20A*=20=
\citep{FalckeMelia1997,CokerMeliaFalcke1999},=20the=20picture=20of=20an=0D=
=0Aoptically=20thin,=20geometrically=20thick=20accretion=20flow,=20=
so-called=0D=0Aadvection-dominated=20or=20radiatively-inefficient=20=
accretion=20flows=20(ADAFs,=0D=0ARIAFs)=20started=20to=20emerge=0D=0A=
\citep{Melia1992a,NarayanMahadevanGrindlay1998,QuataertGruzinov2000a}.=0D=
=0AThese=20models=20initially=20had=20much=20higher=20accretion=20rates,=20=
but=20this=20was=0D=0Abrought=20down=20when=20polarization=20=
measurements,=20using=20Faraday=20rotation=0D=0Aarguments,=0D=0A=
\citep{BowerBackerZhao1999,AitkenGreavesChrysostomou2000,BowerFalckeWright=
2005,MarroneMoranZhao2007}=0D=0Ashowed=20a=20low=20particle=20density=20=
towards=20Sgr=20A*.=20This=20implied=20an=20accretion=0D=0Arate=20below=20=
$10^{-7}M_\odot$/yr.=20Hence,=20our=20Galactic=20Center=20is=20likely=0D=0A=
starving=20as=20well=20as=20radiating=20inefficiently=20and=20producing=20=
a=20jet=0D=0A\citep{YuanMarkoffFalcke2002}.=0D=0A=0D=0A\section{Review=20=
of=20Observational=20Progress}=0D=0AIn=20recent=20years,=20important=20=
progress=20has=20come=20from=20the=20detection=0D=0Aof=20Sgr=20A*=20in=20=
X-rays=20and=20near-infrared=0D=0A=
\citep{BaganoffBautzBrandt2001,GenzelOttEckart2003}=20and=20a=20lot=20of=0D=
=0Aemphasis=20has=20been=20placed=20on=20variability=20studies=20of=20=
Sgr=20A*=20\cite[][to=0D=0Aname=20just=20a=0D=0A=
few]{HerrnsteinZhaoBower2004,Falcke1999a,PorquetGrossoPredehl2008,Mauerhan=
MorrisWalter2005,Yusef-ZadehRobertsWardle2006,MarroneBaganoffMorris2008,Ec=
kartBaganoffZamaninasab2008,MeyerDoGhez2008,Yusef-ZadehBushouseWardle2009,=
Dodds-EdenPorquetTrap2009}.=20The=0D=0Avarious=20campaigns=20have=20=
shown=20that=20flares=20in=20the=20near-infrared=20(NIR)=0D=0Aand=20=
X-rays=20are=20simultaneous=20within=20minutes=20and=20hence=20come=20=
from=20the=20same=0D=0Aregion.=20\cite{Dodds-EdenPorquetTrap2009}=20=
favor=20optically=20thin=0D=0Asynchrotron=20radiation=20over=20inverse=20=
Compton=20as=20the=20dominant=20emission=0D=0Aprocess=20to=20explain=20=
the=20remarkable=20similarity=20of=20a=20particularly=20bright=0D=0A=
flare=20in=20both=20bands.=20On=20the=20other=20hand=20radio/submm-wave=20=
and=20X-ray/NIR=0D=0Aflares=20do=20not=20seem=20to=20be=20simultaneous=20=
and=20no=20generally=20accepted=20lag=0D=0Ahas=20been=20derived,=20=
despite=20various=20claims=20in=20the=20literature,=20which=20are=0D=0A=
ranging=20from=20several=20hours=20to=20minutes.=0D=0A=0D=0AVery=20=
exciting=20has=20also=20been=20the=20progress=20based=20on=20radio=20=
observations,=0D=0Aconstraining=20any=20model=20--=20and=20in=20=
particular=20any=20jet=20model=20--=20much=0D=0Abetter.=20=
\cite{BowerFalckeHerrnstein2004}=20were=20the=20first=20to=20measure=20=
the=0D=0A{\it=20intrinsic}=20source=20size=20of=20Sgr=20A*=20at=2043=20=
GHz=20directly=20using=20Very=0D=0ALong=20Baseline=20Interferometry=20=
(VLBI),=20yielding=20a=20size=20of=20some=2020=0D=0ASchwarzschild=20=
radii=20($R_{\rm=20s}$)=20only.=20This=20was=20a=20true=20breakthrough,=0D=
=0Agiven=20that=20the=20structure=20of=20Sgr=20A*=20had=20been=20washed=20=
out=20due=20to=0D=0Ainterstellar=20scattering=20for=2030=20years=20since=20=
its=20discovery=20(yielding=20a=0D=0Ameasured=20size=20that=20decreases=20=
with=20$\lambda^2$=20at=20low=20frequencies,=0D=0A=
Fig.\,\ref{figsgrsize},=20left).=20=20Further=20VLBI=20measurements=20=
then=0D=0Aprovided=20measurements=20up=20to=20220=20GHz=0D=0A=
\citep{ShenLoLiang2005,DoelemanWeintroubRogers2008}=20giving=20sizes=20=
down=0D=0Ato=20$4=20R_{\rm=20s}$!=20Hence,=20it=20is=20clear=20now=20=
that=20the=20intrinsic=20source=0D=0Asize=20decreases=20with=20=
increasing=20frequency=20(Fig.\,\ref{figsgrsize},=0D=0Aright)=20--=20an=20=
important=20prediction=20of=20the=20jet=20model.=20Direct=20comparison=0D=
=0Aof=20the=20jet=20model=20with=20the=20actual=20VLBI=20data=20shows=20=
a=20consistency=20with=0D=0Athe=20compact=20source=20size=20and=20=
structure,=20but=20does=20favor=20edge-on=0D=0Ageometries=20=
\citep{MarkoffBowerFalcke2007}.=0D=0A=0D=0A\begin{figure}[htb]=0D=0A%=20=
\vspace*{-2.0=20cm}=0D=0A\begin{center}=0D=0A=20=
\includegraphics[width=3D0.49\textwidth]{sgr-lg-size-vs-lambda.eps}=20=
\hfill=20=
\includegraphics[width=3D0.49\textwidth]{sgr-lg-intrinsicsize-vs-lambda.ep=
s}=20=0D=0A%=20\vspace*{-1.0=20cm}=0D=0A=20\caption{Left:=20measured=20=
major=20axis=20size=20of=20Sgr=20A*=20as=20function=20of=0D=0A=20=20=20=
wavelength=20measured=20by=20various=20VLBI=20experiments.=20Right:=20=
Derived=20intrinsic=20size=20of=20Sgr=20A*=20after=0D=0A=20=20=20=
subtraction=20of=20a=20$\lambda^2$=20scattering=20law=20using=20all=20=
available=0D=0A=20=20=20VLBI=20data=20(see=0D=0A=20=20=20=
\cite{FalckeMarkoffBower2009}=20for=20details).=20The=20dashed=20line=0D=0A=
=20=20=20indicates=20the=20systematic=20uncertainties=20due=20to=20=
different=0D=0A=20=20=20normalizations=20of=20the=20scattering=20law.}=0D=
=0A=20=20=20\label{figsgrsize}=0D=0A\end{center}=0D=0A\end{figure}=0D=0A=0D=
=0AAdditional=20information=20has=20come=20from=20the=20measurement=20of=20=
time=20lags=20in=0D=0Athe=20radio=0D=0A=
\citep{Yusef-ZadehRobertsWardle2006,Yusef-ZadehWardleHeinke2008},=20=
where=0D=0Ait=20was=20shown=20that=2043=20GHz=20radio=20flares=20precede=20=
22=20GHz=20flares=20by=20about=0D=0A20=20minutes.=20Given=20that=20the=20=
intrinsic=20size=20difference=20between=20these=20two=0D=0Afrequencies=20=
is=20about=2030=20light=20minutes=20one=20arrives=20at=20the=20natural=0D=
=0Aconclusion=20that=20the=20radio=20emitting=20plasma=20flows=20out=20=
with=20the=20speed=20of=0D=0Alight=20\citep{FalckeMarkoffBower2009},=20=
which=20is=20now=20also=20suggested=20by=20the=0D=0Ashort-time=20=
variability=20of=20the=20source=0D=0A=
\citep{Yusef-ZadehBushouseWardle2009}.=20=0D=0A=0D=0AAlternative=20=
models=20based=20on=20simple=20adiabatic=20expansion=20of=20``blobs''=0D=0A=
which=20expand=20sub-relativisitically=0D=0A=
\citep{Yusef-ZadehRobertsWardle2006,EckartBaganoffMorris2009}=20have=0D=0A=
only=20been=20fitted=20to=20the=20light=20curves=20and=20fail=20to=20=
take=20the=20VLBI=20sizes=0D=0Ainto=20account.=20They=20predict=20much=20=
smaller=20source=20sizes=20and=20would=0D=0Apostulate=20two=20very=20=
different=20emission=20regions,=20while=20fits=20for=0D=0Aadiabatic=20=
expansion=20in=20a=20jet=20\citep{MaitraMarkoffFalcke2009}=20do=0D=0A=
reproduce=20radio=20light=20curves=20and=20VLBI=20sizes=20very=20well.=0D=
=0A=0D=0AIn=20the=20following=20we=20will=20now=20focus=20on=20the=20the=20=
basic=20properties=20of=0D=0Aemission=20from=20a=20jet=20and=20briefly=20=
discuss=20how=20future=20radio=20observations=0D=0Aand=20modeling=20will=20=
provide=20us=20with=20deeper=20insight=20into=20the=20formation=20of=0D=0A=
jets=20close=20to=20the=20event=20horizon.=0D=0A=0D=0A\section{The=20=
Basic=20Jet=20Model}=0D=0AGiven=20the=20observational=20progress=20any=20=
model=20for=20Sgr=20A*=20nowadays=20has=20to=0D=0Aexplain=20the=20=
spectrum,=20size,=20and=20variability=20properties=20of=20the=0D=0A=
source.=20Here=20we=20will=20briefly=20explain=20the=20physical=20=
background,=20how=20many=0D=0Aof=20the=20observed=20properties=20arise=20=
quite=20naturally=20in=20a=20jet=0D=0Amodel.=20Figure=20=
\ref{figspectrum}=20shows=20the=20radio=20spectrum=20of=20Sgr=20A*=20and=0D=
=0Aa=20schematic=20view=20of=20the=20various=20jet=20model=20components.=20=
=20Assume=20a=20hot=0D=0Amagnetized=20plasma=20is=20ejected=20close=20to=20=
the=20black=20hole=20from=20a=20compact=0D=0Anozzle=20and=20expands=20=
freely=20thereafter.=20The=20plasma=20in=20the=20nozzle=20will=0D=0Aemit=20=
synchrotron=20radiation=20peaking=20between=20100=20GHz=20and=20a=20few=20=
THz=20due=0D=0Ato=20optical=20depth=20effects=20(almost=20black=20body=20=
radiation),=20producing=20the=0D=0A``submm-bump''.=20If=20the=20electron=20=
distribution=20is=20non-Maxwellian,=20i.e.,=0D=0Ahas=20a=20high-energy=20=
power-law=20tail,=20optically=20thin=20synchrotron=20radiation=0D=0Awill=20=
appear,=20that=20can=20easily=20extend=20into=20the=20near-infrared=20or=20=
even=0D=0AX-ray=20regime=20(which=20could=20also=20have=20a=20=
contribution=20from=20inverse=0D=0ACompton=20emission=20from=20the=20=
submm-bump).=0D=0A=0D=0A\begin{figure}[htb]=0D=0A%=20\vspace*{-2.0=20cm}=0D=
=0A\begin{center}=0D=0A=20\hfill=20=
\includegraphics[width=3D0.99\textwidth]{sgr-spectrum.ps}=20\hfill=20=0D=0A=
%=20\vspace*{-1.0=20cm}=0D=0A=20\caption{Spectrum=20of=20Sgr=20A*=20and=20=
schematic=20overview=20of=20various=0D=0A=20=20=20contributions=20from=20=
a=20jet.}=0D=0A=20=20=20\label{figspectrum}=0D=0A\end{center}=0D=0A=
\end{figure}=0D=0A=0D=0AWhen=20the=20plasma=20leaves=20the=20nozzle=20=
and=20expands,=20it=20will=20expand=20with=0D=0Asound=20speed=20and=20=
advance=20with=20the=20bulk=20flow=20speed,=20roughly=20filling=20a=0D=0A=
conical=20Mach=20cone.=20=20Like=20in=20a=20multi-color=20accretion=20=
disk,=20the=0D=0Asynchrotron=20emission=20will=20then=20peak=20at=20=
lower=20and=20lower=20frequencies=20the=0D=0Afurther=20out=20the=20=
plasma=20gets.=20=20This=20will=20naturally=20lead=20to=20an=20optically=0D=
=0Athick,=20flat=20radio=20spectrum=20and=20a=20source=20size=20=
$\propto\nu^{-1}$=0D=0A\citep{BlandfordKonigl1979,FalckeBiermann1995}.=20=
With=20the=20jet-disk=0D=0Ascaling=20mentioned=20above=20one=20can=20=
then=20readily=20explain=20flux=20and=20size=20of=0D=0ASgr=20A*=20to=20=
zeroth=20order=20\citep[see][for=20a=20text-book=20level=0D=0A=
description]{Falcke2003}.=20However,=20a=20simple=20Blandford-K\"onigl=20=
model=0D=0Ais=20not=20really=20appropriate,=20since=20close=20to=20the=20=
black=20hole=20the=20pressure=0D=0Agradient=20--=20and=20likely=20other=20=
processes=20as=20well=20--=20will=20lead=20to=20an=0D=0Aacceleration=20=
of=20the=20jet,=20yielding=20an=20inverted=20spectrum=20and=20a=20=
steeper=0D=0Athan=20$\nu^{-1}$=20frequency-size=20relation=0D=0A=
\citep{Falcke1996a,FalckeMarkoff2000}.=0D=0A=0D=0ATo=20understand=20the=20=
variability=20behavior=20one=20has=20to=20remember=20that=20the=0D=0A=
radio/submm=20spectrum=20(<1=20THz)=20is=20optically=20thick=20and=20=
thus=20originates=0D=0Ain=20a=20superposition=20of=20emission=20=
components=20from=20different=20spatial=0D=0Aregions,=20peaking=20at=20=
increasingly=20lower=20frequencies=20as=20their=0D=0Acharacteristic=20=
scale=20increases.=20=20The=20NIR/X-ray=20spectrum,=20on=20the=20other=0D=
=0Ahand,=20is=20optically=20thin=20and=20comes=20from=20one,=20i.e.,=20=
the=20smallest,=0D=0Aspatial=20scale.=20Already=20=
\cite{MarkoffFalckeYuan2001}=20showed=20that=20the=0D=0Ajet=20radio=20=
emission=20will=20mainly=20respond=20to=20changes=20in=20the=20density=20=
(and=0D=0Ahence=20accretion=20rate,=20given=20the=20assumed=20jet-disk=20=
coupling),=20while=20the=0D=0ANIR/X-ray=20emission=20will=20be=20highly=20=
sensitive=20to=20changes=20in=20the=20electron=0D=0Atemperature=20or=20=
power-law=20distribution.=20Comparing=20Sgr=20A*=20to=20a=20lightning=0D=0A=
storm=20on=20earth,=20one=20might=20say=20that=20the=20radio=20would=20=
reflect=20the=20bulk=0D=0Amotion=20of=20the=20clouds=20and=20the=20=
winds,=20while=20NIR/X-rays=20are=20more=20like=0D=0Alightning=20within=20=
the=20clouds.=0D=0A=0D=0A=0D=0AThis=20explains=20the=20high=20NIR/X-ray=20=
variability=20and=20its=20tight=20correlation=0D=0A--=20NIR=20and=20=
X-ray=20both=20reflect=20co-spatial=20changes=20in=20the=20population=20=
of=0D=0Ahigh-energy=20electrons=20in=20the=20nozzle=20region,=20close=20=
to=20the=20event=0D=0Ahorizon.=20Compared=20to=20the=20bulk=20density=20=
of=20the=20flow,=20the=20number=20of=0D=0Ahigh-energy=20electrons=20is=20=
small=20and=20their=20cooling=20time=20is=20fast.=20Hence,=0D=0Aalready=20=
a=20small=20change=20in=20the=20efficiency=20of=20accelerating=20=
non-thermal=0D=0Aelectrons=20can=20lead=20to=20large=20changes=20in=20=
NIR=20and=20X-rays=20without=0D=0Aaffecting=20the=20overall=20energy=20=
budget=20too=20much.=0D=0A=0D=0AOn=20the=20other=20hand,=20to=20produce=20=
radio=20flares=20a=20major=20change=20in=0D=0Athe=20bulk=20density=20of=20=
low-energy=20electrons=20is=20required,=20i.e.,=20a=20change=20in=0D=0A=
accretion=20rate=20and=20total=20jet=20power.=20When=20induced=20at=20=
the=20foot=20point=20the=0D=0Adensity=20surge=20will=20have=20to=20=
propagate=20with=20the=20flow=20speed=20outwards=0D=0A\citep[see][for=20=
detailed=0D=0Amodeling]{FalckeMarkoffBower2009,MaitraMarkoffFalcke2009}.=20=
This=0D=0Asuggests=20lower=20relative=20flux=20changes=20compared=20to=20=
NIR,=20time=20lags=20in=20the=0D=0Asense=20that=20higher-frequencies=20=
lead=20lower=20ones,=20and=20not=20necessarily=20a=0D=0Atight=20=
connection=20between=20major=20radio/mm--flares=20on=20one=20hand=20and=0D=
=0ANIR/X-ray--flares=20on=20the=20other.=20Of=20course,=20it=20is=20=
conceivable=20that=20a=0D=0Asudden=20increase=20in=20accretion=20rate=20=
onto=20the=20black=20hole,=20which=20is=20seen=0D=0Aas=20a=20radio=20=
flare,=20will=20also=20lead=20to=20more=20efficient=20dissipation=20and=0D=
=0Aparticle=20acceleration.=20However,=20in=20any=20case=20NIR/radio=20=
delays=20are=0D=0Alikely=20not=20easy=20to=20interpret=20and=20should=20=
certainly=20not=20be=20used=20to=0D=0Aestimate,=20e.g.,=20time=20scales=20=
for=20adiabatic=20expansion.=20On=20the=20other=0D=0Ahand,=20time=20lags=20=
within=20the=20radio/submm-wave=20regime=20could=20have=20high=0D=0A=
diagnostic=20powers,=20since=20they=20are=20directly=20related=20to=20=
the=20flow=0D=0Aspeed.=20Hence,=20VLBI=20size=20and=20radio=20monitoring=20=
data=20combined=20would=0D=0Aprovide=20unique=20information=20about=20=
the=20acceleration=20and=20formation=20of=0D=0Aastrophysical=20jets=20=
and=20in=20particular=20the=20longitudinal=20velocity=20profile.=0D=0A=0D=
=0A\section{MHD=20Modeling=20and=20Event=20Horizon=20Imaging}=0D=0A=
Parallel=20to=20the=20semi-analytic=20modeling=20a=20new=20breed=20of=20=
MHD=20models=20has=0D=0Abecome=20available,=20some=20of=20which=20are=20=
now=20geared=20towards=20Sgr=20A*.=20These=0D=0Amodels=20basically=20=
start=20from=20first=20principles=20following=20the=20evolution=0D=0Aof=20=
a=20hot=20magnetized=20plasma=20as=20it=20is=20accreted=20onto=20a=20=
black=0D=0Ahole.=20Initially,=20jets=20did=20not=20form=20naturally=20in=20=
these=20simulations=0D=0A\citep[][]{StoneHawleyGammie1996,Hawley2000},=20=
especially=20when=20the=0D=0Ainitial=20configuration=20contained=20only=20=
a=20toroidal=20magnetic=20field,=20while=0D=0Asimulations=20with=20=
random=20or=20poloidal=20fields=20seemed=20well=20to=20be=20able=20to=0D=0A=
produce=20jet-like=20outflows=0D=0A=
\citep[e.g.,][]{KoideShibataKudoh1999,MeierKoideUchida2001}.=20Nowadays,=0D=
=0Amost=20MHD=20simulations=20include=20poloidal=20magnetic=20field=20=
and=20hence=20show=0D=0Asome=20evidence=20for=20jet-like=20outflows.=20=
Given=20the=20excellent=20observational=0D=0Aconstraints=20on=20scales=20=
close=20to=20the=20event=20horizon,=20Sgr=20A*=20has=20now=0D=0Abecome=20=
a=20useful=20testbed=20also=20for=20numerical=20MHD=20simulations=0D=0A=
\cite[e.g.,][]{OhsugaKatoMineshige2005,NobleLeungGammie2007,ChanLiuFryer20=
09,MoscibrodzkaGammieDolence2009,DexterAgolFragile2010,HilburnLiangLiu2010=
}.=0D=0A=0D=0AFor=20example,=20\cite{MoscibrodzkaGammieDolence2009}=20=
have=20performed=0D=0Asimulations=20based=20on=20an=20axisymmetric=20=
version=20of=20the=20GRMHD=20code=20{\it=0D=0A=20=20harm},=20applying=20=
relativistic=20radiative=20transfer=20\citep[grmonty:=0D=0A=
][]{DolenceGammieMoscibrodzka2009}=20and=20GR=20ray=20tracing=20=
\cite[ibothros:=0D=0A][]{NobleLeungGammie2007}=20during=20=
post-processing.=20These=202D=20simulations=0D=0Ado=20indeed=20also=20=
show=20a=20jet-like=20outflow,=20but=20it=20appears=20rather=0D=0Afaint.=20=
Compared=20to=20the=20early=20pure=20GR=20ray=20tracing=20simulations=0D=0A=
\citep{FalckeMeliaAgol2000}=20the=20shadow=20of=20the=20black=20hole=20=
remains=0D=0Avisible=20and=20a=20significant=20part=20of=20the=20=
parameter=20range=20of=20the=20models=0D=0Acan=20be=20excluded.=20In=20=
their=20simulations,=0D=0A\cite{MoscibrodzkaGammieDolence2009}=20find=20=
that=20the=20VLBI=20sizes=20and=0D=0Aother=20properties=20favor=20=
edge-on=20orientations=20and=20a=20fast=20spinning=20black=0D=0Ahole.=0D=0A=
=0D=0A\begin{figure}[htb]=0D=0A%=20\vspace*{-2.0=20cm}=0D=0A=
\begin{center}\includegraphics[width=3D0.7\textwidth]{sgr-mhdmodels+vlbi.p=
s}=0D=0A%=20\vspace*{-1.0=20cm}=0D=0A=20\caption{Left:=20Time-averaged=20=
appearance=20of=202D=20MHD=20accretion=20models=20at=20345=20GHz=0D=0A=20=
=20=20(bottom-left:=20best-fit=20model)=20from=0D=0A=20=20=20=
\cite{MoscibrodzkaGammieDolence2009}.=20Right:=20Reconstructed=20images=0D=
=0A=20=20=20with=20a=20putative=20global=20submm-VLBI=20array.=20=20Top:=20=
face-on=20geometry,=0D=0A=20=20=20Bottom:=20edge-on=20geometry.=20The=20=
black=20hole=20shadow=20is=20clearly=20visible=0D=0A=20=20=20for=20=
face-one=20orientation=20but=20much=20less=20so=20for=20edge-on.}=0D=0A=20=
=20=20\label{figmhdvlbi}=0D=0A\end{center}=0D=0A\end{figure}=0D=0A=0D=0A=
To=20demonstrate=20the=20potential=20of=20this=20approach,=20we=20have=20=
performed=20some=0D=0Asimple=20simulations=20of=20future=20VLBI=20=
observations=20(Figure=0D=0A\ref{figmhdvlbi}).=20For=20this=20we=20have=20=
taken=20the=20predicted=20intensity=0D=0Adistributions=20at=20345=20GHz=20=
(Fig.~\ref{figmhdvlbi})=20from=0D=0A=
\cite{MoscibrodzkaGammieDolence2009},=20smeared=20them=20with=20a=20=
Gaussian=0D=0Akernel=20according=20to=20the=20scattering=20law=20=
\citep[taken=0D=0Afrom][]{FalckeMarkoffBower2009},=20and=20passed=20them=20=
through=20the=0D=0Ainterferometry=20simulation=20tool=20{\it=20simdata2}=20=
in=20{\it=20CASA}=0D=0A\citep{McMullinWatersSchiebel2007}.=20Frequencies=20=
and=20baselines=20were=0D=0Aappropriately=20scaled=20to=20avoid=20=
numerical=20problems=20and=20noise=0D=0Acontributions=20were=20=
neglected.=20The=20array=20layout=0D=0A(Fig.~\ref{figvlbilayout})=20=
consisted=20of=20a=20number=20of=20existing=0D=0A(sub)mm-wave=20=
facilities=20(CARMA,=20SMT,=20JCMT),=20telescopes=20which=20are=0D=0A=
planned,=20are=20under=20construction=20or=20are=20not=20yet=20equipped=20=
for=20VLBI=0D=0A(LLAMA,=20ALMA,=20LMT,=20SPT),=20and=20one=20putative=20=
site=20in=20Peru=20to=20fill=20in=0D=0Amissing=20baselines.=0D=0A=0D=0A=
One=20can=20see=20that=20indeed=20such=20an=20array=20would=20be=20well=20=
matched=20to=20the=0D=0Aresolution=20needed=20to=20study=20event-horizon=20=
scale=20structures=20in=20Sgr=0D=0AA*.=20High=20spin=20and=20inclination=20=
will=20produce=20a=20rather=20compact=20emission=0D=0Aregion=20with=20a=20=
size=20of=20$\sim2-4=20R_{\rm=20g}$=20and=20a=20shadow=20that=20is=20=
difficult=0D=0Ato=20see=20unless=20one=20achieves=20sufficient=20dynamic=20=
range=20($\sim100:1$).=0D=0A=0D=0AIt=20will=20be=20interesting=20to=20=
see=20how=20this=20picture=20changes=20as=20the=0D=0Asimulations=20=
improve.=20Figure~\ref{figvlbilayout}=20(right)=20shows=20a=0D=0A=
snapshot=20of=20a=20single=20frame=20from=20a=20preliminary=203D=20GRMHD=20=
simulation=20with=0D=0A{\it=20harm},=20again=20including=20ray=20tracing=20=
and=20radiation=20transport,=20for=20a=0D=0Ablack=20hole=20spin=20of=20=
a=3D0.9.=20While=20in=20the=202D=20simulation=20the=20jet=20is=20very=0D=0A=
dim,=20to=20the=20point=20that=20it=20is=20not=20even=20visible=20in=20=
the=20emission=20maps=0D=0Apresented=20here,=20the=20jet=20becomes=20=
much=20more=20prominent=20in=20the=203D=0D=0Acase.=20This=20is=20=
apparently=20due=20to=20an=20increased=20electron=20temperature=20in=0D=0A=
the=20jet,=20possibly=20coming=20from=20increased=20acoustic=20heating.=20=
Clearly,=20the=0D=0Aelectron=20temperature=20in=20disk=20and=20jet=20=
plays=20and=20important=20role=20for=20the=0D=0Aappearance=20of=20Sgr=20=
A*,=20but=20it=20is=20also=20the=20least=20understood=0D=0Aparameter.=20=
Such=20simulations=20provide=20a=20taste=20for=20the=20future=20=
direction=0D=0Athe=20field=20can=20evolve=20to.=0D=0A=0D=0A=
\begin{figure}[htb]=0D=0A%=20\vspace*{-2.0=20cm}=0D=0A\begin{center}=0D=0A=
\begin{tabular}{cc}=0D=0A=
%\includegraphics[width=3D0.4\textwidth]{mmvlbiarray.ps}=20&=20=
\vbox{\vspace{-2cm}\includegraphics[width=3D0.4\textwidth]{gammie3DMHDmode=
l_a=3D0.9.ps}\vspace{2cm}}=0D=0A=
\includegraphics[width=3D0.4\textwidth]{mmvlbiarray.ps}=20&=20=
\raisebox{0.2cm}{\includegraphics[width=3D0.394\textwidth]{gammie3DMHDmode=
l_a=3D0.9.ps}}=0D=0A%=20=0D=0A\end{tabular}=0D=0A\caption{Left:=20=
Google-Earth=20view=20of=20the=20Earth=20with=20positions=20of=20the=0D=0A=
=20=20submm-VLBI=20stations=20used=20in=20the=20simulation=20as=20green=20=
boxes.=20Right:=0D=0A=20=20Snapshot=20of=20a=203D=20GRMHD=20simulation=20=
with=20similar=20parameters=20as=20in=0D=0A=20=20Fig.~\ref{figmhdvlbi}.=20=
Shown=20is=20the=20intensity=20at=20345=20GHz.=20The=20jet=20is=0D=0A=20=20=
much=20more=20visible,=20compared=20to=20the=202D=20case.}=0D=0A=20=20=20=
\label{figvlbilayout}=0D=0A\end{center}=0D=0A\end{figure}=0D=0A=0D=0A=
\section{Conclusions}=0D=0AThere=20is=20no=20other=20supermassive=20=
black=20hole=20with=20such=20a=20wealth=20of=0D=0Ainformation.=20The=20=
properties=20are=20not=20different=20from=20many=20other=20radio=0D=0A=
cores=20in=20nearby=20low-power=20AGN=20when=20appropriately=20scaled=20=
to=20a=20very=20low=0D=0Aaccretion=20rate=20=
\citep{FalckeBiermann1999,NagarFalckeWilson2005,MarkoffNowakYoung2008}.=20=
In=0D=0Afact,=20within=20the=20fundamental=20plane=20of=20black=20hole=20=
activity=0D=0A=
\citep{MerloniHeinzdiMatteo2003,FalckeKordingMarkoff2004,KordingFalckeCorb=
el2006},=0D=0Athat=20has=20been=20discussed=20at=20length=20in=20this=20=
meeting,=20it=20represents=0D=0Aalmost=20an=20extreme=20``off-state''.=0D=
=0A=0D=0ASpectrum,=20size,=20and=20radio=20time-lags=20and=20evolution=20=
in=20Sgr=20A*=20strongly=0D=0Asuggest=20a=20jet-nature=20of=20the=20=
radio=20emission,=20with=20mildly=20relativistic=0D=0Aoutflow=20speeds.=20=
Since=20the=20the=20submm-wave=20emission=20comes=20from=20the=0D=0A=
direct=20proximity=20of=20the=20event=20horizon,=20Sgr=20A*=20is=20an=20=
ideal=20source=20to=0D=0Aimage=20the=20shadow=20of=20the=20event=20=
horizon=20{\it=20and}=20to=20find=20out=20how=0D=0Aastrophysical=20jets=20=
are=20formed=20--=20for=20example=20by=20combining=20mm-VLBI=0D=0A=
observations=20and=20time-lag=20measurements.=20=20=0D=0A=
\bibliographystyle{aa}=0D=0A\bibliography{hfrefs}=0D=0A=0D=0A=0D=0A=
\begin{discussion}=0D=0A=0D=0A\discuss{C.=20Fendt}{What=20is=20your=20=
heating=20model=20for=20the=20electrons.=20This=0D=0A=20=20is=20beyond=20=
MHD.}=0D=0A=0D=0A\discuss{H.=20Falcke}{It=20is=20essentially=20local=20=
numerical=20dissipation.}=0D=0A=0D=0A\discuss{Luis.=20F.=20Rodriguez}{Is=20=
there=20any=20chance=20of=20seeing=20the=20jet=20a=0D=0A=20=20few=20=
arcsec=20away=20from=20Sgr=20A*=20using=20an=20ultra-sensitive=20radio=20=
array=20like=0D=0Athe=20EVLA?}=0D=0A=0D=0A\discuss{H.=20=
Falcke}{Unfortunately=20does=20the=20Sgr=20A*=20size=20grow=20roughly=0D=0A=
=20=20with=20$\lambda$=20while=20the=20scattering=20size=20grows=20with=20=
$\lambda^2$,=20hence=0D=0A=20=20the=20core=20will=20always=20be=20hidden=20=
at=20lower=20frequencies.=20Perhaps=20one=0D=0A=20=20could=20see=20some=20=
interaction=20region=20further=20out,=20but=20teh=20Galactic=20Center=20=
is=20a=20very=20complicated=0D=0A=20=20region.}=0D=0A=0D=0A\discuss{S.=20=
Corbel}{Do=20you=20have=20any=20idea=20why=20we=20live=20in=20a=20galaxy=20=
with=0D=0A=20=20the=20faintest=20LLAGN?}=0D=0A=0D=0A\discuss{H.=20=
Falcke}{Estimates=20for=20the=20accretion=20rate=20based=20on=0D=0A=20=
environmental=20factors=20are=20all=20many=20orders=20of=20magnitude=20=
above=20the=0D=0A=20=20current=20value.=20Maybe=20we=20live=20in=20a=20=
special=20time.=20For=20example,=20the=0D=0A=20=20nearby=20supernova=20=
remnant=20Sgr=20A=20East=20has=20probably=20just=20swept=20over=20the=0D=0A=
black=20hole=20a=20few=20thousand=20years=20ago.=20Such=20local=20=
effects=20could=20easily=20disrupt=0D=0Aa=20steady=20accretion=20flow.}=0D=
=0A=0D=0A\discuss{E.=20de=20Gouveia=20Dal=20Pino}{Do=20you=20think=20=
that=20the=20time=20lag=0D=0A=20=20technique=20will=20be=20able=20to=20=
separate=20the=20complex=20motions=20that=20may=0D=0A=20=20occur=20at=20=
launching=20like,=20for=20instance,=20rotational=20velocity=20from=20the=0D=
=0A=20=20$v_{\rm=20z}$=20component?}=0D=0A\discuss{H.=20Falcke}{Good=20=
question=20--=20helical=20motion=20is=20indeed=20quite=0D=0A=20=20=
commonly=20observed=20in=20quasar=20jets=20with=20VLBI.=20Rotation=20=
will=20lead=20to=0D=0A=20=20differential=20beaming=20and=20hence=20will=20=
imprint=20a=20wobble=20as=20a=20function=0D=0A=20=20of=20frequency=20on=20=
top=20of=20the=20flare=20spectrum.=20Maybe=20with=20very=20sensitive=0D=0A=
=20=20broad-band=20monitoring,=20e.g.=20with=20ALMA=20and=20SKA=20in=20=
the=20future,=20might=0D=0A=20=20such=20subtleties=20be=20detectable.}=0D=
=0A\end{discussion}=0D=0A=0D=0A\end{document}=0D=0A=

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Prof. Dr. Heino Falcke

Professor of Astroparticle Physics and Radio Astronomy - Radboud Univ.
LOFAR International Project Scientist - ASTRON, Dwingeloo
  	
Department of Astrophysics, IMAPP, Radboud Universiteit
P.O. Box 9010, 6500 GL Nijmegen, The Netherlands
(Visitors: Heyendaalseweg 135, 6525 AJ Nijmegen, The Netherlands)

Web: 	www.astro.ru.nl/~falcke
Tel:     	+31 (0)243652020    	Mobile:  	+49 (0)15123040365
Fax:     	+31 (0)243652807   	Secr:    	+31 (0)243652804
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