[mmaimcal]BIWEEKLY CALENDAR OF THE ALMA PROJECT at NRAO

Sat Jun 5 17:37:49 EDT 2004

                        BIWEEKLY CALENDAR OF THE ALMA PROJECT at NRAO
                                June 7 - June 21, 2004

******************************** THIS BIWEEK ***********************************
The Board has reopened the search for the ALMA JAO Project Scientist.

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Denis Urbain, Christian Holmstedt and Wes Grammer arrive at the NTC in Charlottesville 
from their former post in Tucson.

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Past issues of this Calendar may be viewed at 
http://www.cv.nrao.edu/~awootten/mmaimcal/ALMACalendars.html

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General Happenings

Chile        A request for bids for the AOS building foundation has been issued; 
              excavation is expected to commence in the fall. Space on the 18th floor of
              an office building in Santiago has been secured for offices to open there in
              the Fall.  Board, lodging and cleaning services at the ALMA Camp at the OSF site
              started on 01-Jun-2004.  The camp currently houses approximately 10 ALMA persons. Both 
              EU and NA personnel now maintain a presence at the ALMA Camp.  About 69 people
              now work at this site.

ATF          Tests of the prototype antennas have concluded and the Antenna Evaluation Group
              has filed a report on the results.  Systems Engineering now assigns ATF tasks.

NAASC        Paul vanden Bout will return from his sabbatical to assume duties as NAASC Head.
              A new ALMA promotional video is available from EPO.

NTC          Tucson group arriving.  Tests of the 1.3mm Band cartridge third tuning structure 
              on the new (50mm) wafer have yielded good results with noise temperatures within the 
              ALMA specifications.The first station card/filter card test fixture was completed 
              and checked out at the University of Bordeaux for testing of the Tunable Filter Bank 
              cards and digitizers. A second such test fixture was completed and is now working in 
              Charlottesville.

AOC          CDR2 document set submitted for internal review (June 10-12).  SE & I IPT meeting 
              with Project Engineer Rick Murowinski held last week in Socorro.  Three engineers 
              from Bordeaux will be in Socorro this week to assess Digitizer-Correlator interface
              performance.

TUC          Prototype System Integration Planning effort is continuing in both Tucson and Socorro.
              Construction of the RF Simulator is proceeding.  The central LO reference modules are
              being integrated into the Central LO Rack.

DAILY CALENDAR (Times EDT)

Mon  07
All Day ALMA Band 7 (275-373 GHz) Preliminary Design Review, Grenoble
10:30 AM-12:00 PM: JAO/IPT Teleconference
Tue  08
All Day ALMA Band 7 (275-373 GHz) PDR, Grenoble
11:00 AM: ALMA Science Software Requirements telecon (members)
                        Agenda: http://almasw.hq.eso.org/almasw/bin/view/SSR/2004-06-09
4:00 PM-5:00 PM: NAScienceIPT teleconference will not be held this week.
Wed  09
11:00 AM-12:00 PM: Software Science Req. Group Teleconference
Thu  10
All day event: ESO Holiday
8:30 AM-10:00 AM: JAO Teleconference
Fri  11 

Mon  14
1:00 PM-2:30 PM: NA DH Teleconference
Tue  15
10:30 AM-11:00 AM: Science IPT Telecon
4:00 PM-5:00 PM: NAScienceIPT teleconference (open to all interested parties)
                        (434)296-7082
                        Agenda: http://www.cv.nrao.edu/~awootten/mmaimcal/
Wed  16  
Thu  17
8:30 AM-10:00 AM: JAO Teleconference
Fri  18  Sat  

****************************** UPCOMING EVENTS ******************************
#ALMA Calendar  

    * 7-8 June -- ALMA Band 7 (275-373 GHz) PDR, Grenoble
    * 22-23 June -- ALMA Board Meeting, Garching
    * 8-10 July -- Software IPT CDR II, Denver, Colorado.
    * 24 September -- ALMA/EU Meeting, Garching
    * 11-12 Oct -- AMAC Meeting, Florence, Italy

******************************* TECHNICAL NEWS *******************************
ALMA MEMO #493  Finding Fast Switching Calibrators for ALMA
M.A. Holdaway, C. Carilli, R. Laing  2004-04-29 
In order to perform fast switching phase calibration effectively, we need 
to have a database of bright point-like sources at millimeter wavelengths. 
Optimally, this would include flux measurements at 86 GHz and spectral information 
at higher frequencies. We present a sample of 31145 compact flat spectrum radio 
sources with -40 < dec < +60, presumed extragalactic, which will be likely 
candidates for calibrator sources. A sample of variable steep spectrum source 
(ie, sources that could harbor a flat spectrum core even though they appear to 
be steep spectrum) adds another 1767 sources. And a sample of weak but highly 
inverted sources adds another 5296 potential sources to observe. Hence, we have 
as many as 38208 sources which are likely to be detected at millimeter wavelengths, 
though some of the steep spectrum variable sources and highly inverted source 
candidates may be abandoned based on detection rate. The Prototype Interferometer 
(PI) at the ALMA Test Facility (ATF) may be available to verify if these sources 
are indeed bright at 86 GHz. The sensitivity of the prototype receivers should 
permit a noise level of about 3.5 mJy at 86 GHz and about 10 mJy at 250 GHz. 
We expect about a third of the sources will be brighter than 20 mJy at 86 GHz, 
and these detections will be reobserved at 86, 106, 215, and 263 GHz to 
determine the spectrum at higher frequencies and to have some data on 
variability. These observations should take about 80-90 days of time on 
the Prototype Interferometer, and it is suggested that these observations 
could be done at night in the spring and fall of 2005,subject to availability 
of equipment and manpower.

View a pdf version of ALMA Memo #493. 
http://www.alma.nrao.edu/memos/html-memos/alma493/memo493.pdf

ALMA MEMO #497 ANALYSIS OF WIND DATA GATHERED AT CHAJNANTOR 
Juan Pablo Pérez Beaupuits (ESO), Angel Otárola (ESO), 
Fredrik T. Rantakyrö (ESO),Roberto C. Rivera (ESO)
Simon J. E. Radford (NRAO), Lars-Åke Nyman (ESO) 2004-05-07 

A general description and statistics of the wind speeds and directions
registered at the ALMA site during 2001 and 2002 are presented.
Measurements from different wind directions within 22.5º (in azimuth),
topographic sectors and two markedly different daily periods were
obtained. Spectra of the wind turbulence are presented for three wind
speed conditions. During the diurnal period the convective turbulence
and mean wind speed determine the shape and magnitude of the wind
spectra, whereas in the nocturnal period the effects of the mechanical
turbulence, such as the wind shear and surface roughness together with
the mean wind speed, become relevant. No significant differences were
found between the spectra obtained from three topographic sectors in the
diurnal period, whereas in the nocturnal period a statistical test
showed a significant difference for a particular topographic sector and
for a given wind speed range, reflecting changes in the wind spectrum
structure due to the local topography. General models of average spectra
were found for three mean wind speeds, in the diurnal and nocturnal
periods. Relations between the models and the mean wind speed were
found. These relations makes it possible to estimate the spectral
behaviour of the wind at the ALMA site for different mean wind speeds,
which will be useful in the study of the wind loading on the antenna
structure and pointing. Based on the results we can also conclude that
the performance of the ALMA antenna regarding wind load is expected to
be better for both daytime and nighttime periods. 

View a pdf version of ALMA Memo #497. 
http://www.alma.nrao.edu/memos/html-memos/alma497/memo497.pdf

ALMA MEMO # 499    An Approach Detecting the Event Horizon of SgrA*  
 Makoto Miyoshi, Seiji Kameno, Jose K. Ishitsuka, Zhi-Qiang Shen, Rohta Takahashi, 
 Shinji Horiuchi    2004-05-20 00:00 
Imaging the vicinity of a black hole is one of the ultimate goals of VLBI astronomy. 
 The closest massive black hole, SgrA*, located at the Galactic center is the leading candidate 
 for such observations. Combined with recent VLBI recording technique and submillimeter radio 
 engineering, we now have the sufficient sensitivity for the observations. Here we show 
 performance simulations of submillimeter VLBI arrays for imaging SgrA*. Good images are 
 obtained from submillimeter VLBI arrays in the southern hemisphere composed of more than 
 10 stations. We also note that even with a small array, we can estimate the shadow size and 
 then the mass of black hole from visibility analysis. Now, all we need is to construct a 
 submillimeter VLBI array in the southern hemisphere if we wish to unveil the black hole 
 environment of SgrA*.

View a pdf version of ALMA Memo #499. 
http://www.alma.nrao.edu/memos/html-memos/alma499/memo499.pdf

ALMA MEMO #500  Wind power spectrum near Chajnantor
S. Sakamoto (NAOJ), H. Ishizaki (NAOJ), K. Kohno (IoA, U. Tokyo) 2004-05-20

We present wind power spectral density up to ~1 Hz measured near Cerro Chajnantor. The 
power spectral density of variable component is represented by its value around 0.1 Hz. 
Median values of the wind power spectral density are smaller than those predicted by 
the Simiu model with a roughness length of 0.05 m in most cases. The 90-percentile 
values of the wind power spectral density are approximately three times larger than 
the corresponding median values. The wind power spectral density is not a simple 
function of mean wind velocity, and sometimes shows significant suppression after 
sunset. There exists no significant change of the wind power spectral density and 
roughness length that depend on the wind direction. Agreement of wind velocity measured 
at 8.0 m and 3.0 m above the surface within a few 10% difference supports small 
roughness length (<< 0.5). The van der Hoven spectrum extracted from long-term weather 
station data implies that the weather system in this area is very stable and change of 
mean wind velocity (i.e., duration of gusty conditions) is dominated by the diurnal cycle.

View a pdf version of ALMA Memo #500.
http://www.alma.nrao.edu/memos/html-memos/alma500/memo500.pdf

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Please send information for upcoming calendars by Friday evening of the
preceding biweekly period to Janet Bauer or Al Wootten via e-mail 
(jbauer at nrao.edu or awootten at nrao.edu).

The calendar will be issued between late Friday and sometime on Monday by e-mail
to all NRAO scientific staff members and anyone else interested. A specific
mailing list, alma-info, has been created for anyone wishing to receive it.  Past issues
are now available at http://www.cv.nrao.edu/~awootten/mmaimcal/ALMACalendars.html