CSOLOGO1 CSOLOGO2The CSO antenna obtained fringes with SMA antennas, 

as part of the eSMA project. 



    The eSMA (expanded Submillimeter Array) is a project which synthesizes the signals detected with
the CSO 10.4 meter antenna, the JCMT 15 meter antenna, and eight 6-meter SMA antennas. The eSMA
allows us to improve sensitivities and spatial resolution significantly (almost twice improved) compared
with the capability of the SMA itself. 

     The eSMA testing was done under fair weather condition (tau225 ~ 0.1-0.15) on 12 Dec 2005,
following the first engineering run on 6th of December 2005.  For this run, 8 antennas were used
(six SAO SMA antennas, CSO and JCMT).  We observed a lot of quasars to determine baseline
parameters of the CSO.  This experiment was interesting particularly because z (one of the baseline
parameters) was not determined yet for the CSO antenna.   In this experiment, the CSO is named as
antenna 9.  Note that antenna 1 through 6 are for the SMA antennas, antenna 10 is JCMT.  No fringes
were detected with antenna 10 because of some tuning issue JCMT had on the day unfortunately.  
Figure 2 is the array configuration of the SMA antennas.  They were in the compact configuration this time. 



fringes-12dec2005

Figure 1.  Phase (dots in various colors) and amplitude (narrow grey lines) variations of fringes on all baselines towards
various quasars measured in an eSMA experiment done in December 2005.  Numbers noted in left side (such as 1-2)
indicates the baseline between the two antennas.   The CSO telescope (assigned as antenna 9) obtained clear fringes with
all the SMA antennas joined in this experiment.  (Fringes are detected if dots are clustering.  ) This is one of the plots
which the SMA team develops for the regular interferometric observations. 



arrayconfig-12dec2005

Figure 2. The array configuration of the SMA antennas in the experiment done on 12 Dec 2005.  (Note that antenna 7
on pad 11 did not join this experiment.  ) This is one of the plots which the SMA team develops for the regular
interferometric observations.