# TANAMI: Milliarcsecond Resolution Observations of Extragalactic Gamma-ray Sources 

Roopesh Ojha 1 , $^{2}$, Matthias Kadler3 , 4 , 5 , $^{6}$, M. B¨ ock 3 , $^{4}$, R. Booth$^{7}$, M. S. Dutka$^{8}$, P. G. Edwards$^{9}$, A. L. Fey$^{1}$, 

L. Fuhrmann $^{10}$, R. A. Gaume$^{1}$, H. Hase$^{11}$, S. Horiuchi$^{12}$, D. L. Jauncey$^{9}$, K. J. Johnston$^{1}$, U. Katz$^{4}$, 3 

M. Lister $^{13}$, J. E. J. Lovell$^{14}$, Cornelia M¨ uller , $^{4}$, C. Pl¨ otz $^{15}$, J. F. H. Quick$^{7}$, E. Ros10 , $^{16}$, G. B. Taylor$^{17}$, 

D. J. Thompson $^{18}$, S. J. Tingay$^{19}$, G. Tosti20 , $^{21}$, A. K. Tzioumis$^{9}$, J. Wilms3 , $^{4}$, J. A. Zensus10 

$^{4}$ECAP, Universit¨ at Erlangen-N¨ urnberg, Germany 

$^{10}$MPIfR, Auf dem H¨ ugel 69, 53121 Bonn, Germany $^{11}$BKG, Univ. de Concepcion, Casilla 4036, Correo 3, Chile 

$^{12}$Canberra Deep Space Communication Complex, PO Box 1035, Tuggeranong, ACT 2901, Australia 

$^{15}$BKG, Geodetic Observatory Wettzell, Sackenrieder Str. 25, 93444 Bad K¨ otzting, Germany 

$^{21}$Dipartimento di Fisica, Universit` a degli Studi di Perugia, 06123 Perugia, Italy 

$^{1}$United States Naval Observatory, 3450 Massachusetts Ave., NW, Washington DC 20392, USA 

$^{2}$NVI, Inc., 7257D Hanover Parkway, Greenbelt, MD 20770, USA 

$^{3}$Dr. Remeis-Sternwarte, Sternwartstr. 7, 96049 Bamberg, Germany 

$^{5}$CRESST/NASA Goddard Space Flight Center, Greenbelt, MD 20771, USA 

$^{6}$USRA, 10211 Wincopin Circle, Suite 500 Columbia, MD 21044, USA 

$^{7}$Hartebeesthoek Radio Astronomy Observatory, PO Box 443, Krugersdorp 1740, South Africa $^{8}$The Catholic University of America, 620 Michigan Ave., N.E., Washington, DC 20064, USA 

$^{9}$CSIRO Astronomy and Space Science, PO Box 76, Epping, NSW 1710 Australia 

$^{13}$Dept. of Physics, Purdue University, 525 Northwestern Avenue, West Lafayette, IN 47907, USA 

$^{14}$School of Mathematics & Physics, Private Bag 37, Univ. of Tasmania, Hobart TAS 7001, Australia 

$^{16}$Dept. d’Astronomia i Astrof´ısica, Universitat de Val`encia, 46100 Burjassot, Val`encia, Spain 

$^{17}$Dept. of Physics and Astronomy, University of New Mexico, Albuquerque NM, 87131, USA 

$^{18}$Astrophysics Science Division, NASA Goddard Space Flight Center, Greenbelt, MD 20771, USA 

$^{19}$Curtin Institute of Radio Astronomy, Curtin University of Technology, Bentley, WA, 6102, Australia 

$^{20}$Istituto Nazionale di Fisica Nucleare, Sezione di Perugia, 06123 Perugia, Italy 

The TANAMI (Tracking AGN with Austral Milliarcsecond Interferometry) and associated pro- grams provide comprehensive radio monitoring of extragalactic gamma-ray sources south of decli- nation − 30 degrees. Joint quasi-simultaneous observations between the Fermi Gamma-ray Space Telescope and ground based observatories allow us to discriminate between competing theoretical blazar emission models. High resolution VLBI observations are the only way to spatially resolve the 

