ira newsletter · cept for minor problems, for example a power failure at effelsberg caused during...

IRA Newsletter

Number 1. January 1, 1992

1123445678

Contents

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VLBI • . • • . . • •

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Interferometer • • • • • • . • • • • • .....Receivers • . • . •

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Backends • . • • . • • • . . • • • • •Computers ....................................................Data Reduction Software and Hardware •Scientific results ...........................................Call for Observing Proposals on the 30m TelescopeCall for Observing Proposals on the Plateau de BureInterferometer .......................................................Position Open • • • . ...........

Foreword

As mentioned above, TRAM offers to include extendedabstracts describing new scientific results in the Newslet-ter series. I think it is in our own interest that this will pro-duce as much as possible a complete and balanced pictureof what is going on at the TRAM telescopes. This goal can,however, only be achieved if it is fully supported by theuser community. I therefore invite you to submit extended.abstracts of your work to the Editor of the Newsletter se-ries, Dr. Robert LUCAS at TRAM-Grenoble, perhaps assoon as your results have been written up for a journaland have been accepted for publication. Your contribu-tions can be sent at any time and would normally be in-cluded in the next Newsletter edition.

As this is the first TRAM Newsletter after a long time13 and as the concept still leaves some room for adjustments,15 we would welcome your ideas and comments to help to

optimize this new means of communication within theTRAM community and beyond.

Michael GRE WING

Foreword30-m Telescope

This is the first edition of the TRAM Newsletter serieswhich will from now on be produced at regular intervalsto improve the communication between TRAM, the usersof the TRAM telescopes, and the wider astronomical com-munity.

In these Newsletters the main emphasis will be (I) onnew developments relating to the TRAM telescopes onPico Veleta and on Plateau de Bure including equipmentand infrastructure changes, (2) on major developmentactivities in the Grenoble laboratories and in the com-puter group, and (3) on scientific results obtained withthe TRAM telescopes. Prior to an upcoming deadline forthe submission of new observing proposals, the Newslet-ters will also contain a reminder and the relevant infor-mation for the next period. In addition we shall includefrom time to time statistics on the use of the telescopesand other information that we think might be of inter-est to a wider community. We would like to include aswell reports from meetings of the TRAM committees, andannounce upcoming events.

30-m Telescope

REFLECTOR SURFACE

An adjustment of the reflector surface was made in Au-gust 600 screws were moved); a 3 mm phase retrievalholography measurement with the transmitter installedon the top of Pico Veleta (2.8 km distance, II° ele-vation) was made in October. Limited time and poorweather conditions prevented so far a check from efficiencymeasurements. Phase retrieval holography was started at39.6 Gliz using the geostationary satellite ITALSAT at anelevation of 43° , which is a favourable elevation for surfacemeasurements since the analysis does not require gravita-tional corrections. The 7 mm VLBI receiver (MPTfR) wasused for this experiment.

1

3C84 43.200 GHz 1991.68

0 —2

—2

—4

2 IRAM Newsletter January 1, 1992

Departure Departurefrom Granada from Telescope

Monday 8:15 10:45Tuesday 8:15 10:45 and 16:30Wednesday no transportThursday 10:00 (only material) 15:00Friday 8:15 16:00

Table 1: 30-m Telescope winter transport schedule

REMOTE OBSERVING FROM GRANADA

Although the possibility of remote observing from theGranada office has been advertized several times, the re-quest for this mode of observation has been small. Forshort observing programs (typically 10 - 15 hours) withfew tunings (2 - 3) this observing mode offers particularcomfort in winter, avoiding occasionally difficult access tothe telescope. The screen displays (pointing, spectra) atthe Granada office are the same as at the telescope, theinteraction with the telescope is via OBS, the communi-cation with the telescope operator is via e—phone and/ornormal telephone line, the data (spectra .30m) are avail-able via the computer link.

Observers willing to use this facility should please in-form us on their "Confirmation of Observing Time".

SOLAR OBSERVATIONS

A test was made to find out whether the telescope caneventually be used for solar observations; the test con-cerned the heating of the subreflector when pointing thetelescope towards the Sun. Measurements were made withan 11 micron radiation thermometer pointed at the sub-reflector, the results showed an increase in temperature of5.1t 70 of the subreflector with respect to ambient.

Replies are solicited in order to poll the interest in solarobservations.

WINTER TRANSPORT SCHEDULE

The winter transport schedule will come into operationfrom on end of December, depending on snow condition.For operational reasons please follow the schedule (ta-ble 1). No transport is available on weekends, except foremergencies.

Albert GREVE

Relative R.A. (milliarcsec)

Figure 1: Preliminary map of 3C84 obtained from theVLBI data taken with Pico Veleta, Effelsberg, and On-sala at 7 mm.

VLBI

A VLBI test experiment was performed on 5th/6thSeptember between the Onsala 20m antenna, Effelsberg100m and TRAM Pico Veleta 30m antenna. VLBI ses-sions at 7mm take place regularly once or twice per year,but an increase in network sensitivity and coverage is ur-gently needed to improve mapping quality and to allowmore objects to be mapped. Funding to equip the PicoVeleta antenna was kindly provided by the VW founda-tion, enabling us to purchase a VLBA recording termi-nal, hydrogen maser and a GPS satellite time and posi-tion receiver. The VLBA equipment was used in a modecompatible with the Mk3 VLBI format, giving 56Mllzrecorded bandwidth. The compact sources to be observedwere chosen to cover several classes of sources in which weare interested. To allow easy detection of fringes 3C273Bwas included, also a number of weak sources which are

January 1, 1992 IRAM Newsletter 3

at the sensitivity limit of the present network. We alsoincluded the SiO line at 43122 MHz in Orion IRC2. Ex-cept for minor problems, for example a power failure atEffelsberg caused during carpet laying, all stations per-formed well. Preliminary analysis of the data at the BonnMk3 correlator has been completed, showing "fringes" onall baselines. A minor format problem caused by a bugin the VLBA terminal control program did not degradethe data. A reduction in phase coherence during daytimesat all antennas was noted, which can be attributed to at-mospheric instability under late summer conditions. Thisnecessitates the use of short (20 second) coherent integra-tion times for much of the experiment. Source structuremodels or simple maps can be constructed for many of thesources, for instance the map of 3C273 shows significantchanges compared to data taken on a global 6-station net-work in April 1991. During this time the flux density ofthe source has also increased considerably. 0J287 seemsto be unresolved. We show a map of 3C84 (figure 1).

The next step is to commission phase-stable oscillatorsystems to allow VLBI at Pico Veleta at shorter wave-lengths, for instance 3mm. At a frequency of 86GHz sev-eral antennas, including Effelsberg and VLBA antennas,have receiving systems or plan to acquire them. Higherfrequencies, such as 230GHz, will also be possible in thefuture, but this is very much an experimental area at themoment.

Dave GRAHAM

Interferometer

OBSERVING PROJECTS

After one year of operations, the Plateau de Bure- inter-ferometer has fully completed 19 projects. Only 1 projecthad to be cancelled after the first configuration because ofinsufficient sensitivity. 8 projects are currently observed,4 are almost finished, 3 half complete, and 1 just started.This gives a precise idea of how many projects can be car-ried on with the current 3 antenna system: 25 to 30 peryear. Effectively about 30% of the time has been used forproject observations, the remaining being maintenance,tests, improvements, and bad weather.

The repartition of the 27 projects per country is thefollowing:

Country By First With AllAuthors Authors

TRAM 7.0 6.40Germany 6.5 6.35France 9.0 8.25Spain 3.0 2.25USA 1.5 3.20other 0.0 0.55

Per category of projects, the repartition is:

Star Formation, PMS 9Circumstellar Envelopes 71Galaxies 7Others 4

'including one project equivalent to several syntheses

ANTENNAS

— Surface: All antennas have been measured by holog-raphy. Antenna 3 and 2 surfaces have been read-justed. In Antenna 3, this brought the rms surfaceaccuracy down from 108 pm to 72 pm. There isstill room for improvements in surface accuracy, sincesome large scale patterns are still visible.

— Pointing: A new type of inclinometer (liquid sur-face, bi-directional and temperature compensated)has been tested on Antenna 1. It significantly im-proves the accuracy of inclination measurements. Allantennas will be upgraded with this new model,which will allow compensation of inclination varia-tions (known to exists up to 10") on time scales of 2hours, or even shorter.

RECEIVERS

—Antenna 3 receiver has been exchanged. The new re-ceiver, with and TRAM mixer and Nb junction anda Yebes HEMT IF amplifier, has excellent perfor-mances: TREC = 40 to 70 K, with ITSB rejectionTbeLtswBeen 0 and 7 dB. On December 6, we measuredthe lowest system temperature ever recorded at Bure:

= 145 K (main beam brightness scale) at 88.6GHz L.. At 115 GHz, which is only reachable in USB,obtaining a good USBASB ratio is delicate, and theeffective TRZC (USB) is about 100 K.

—Given its relatively poor performances in the bandcenter (93-105 Gliz) in comparison with the new SISmixers, the Schottky receiver will be replaced in 1992.

BACKENDS

—The new correlator should become available on thesite in May-June 1992. Each of the 6 independentunits have the following characteristics:

- tunable LO3 range over 100-600 MHz IF by0.625 MHz steps

• choice of 4 operating modes:

bandwidth channels resolutiona 2 x 80 MHz 2 x 32 2.5 MHzb 2 x 40 MHz 2 x 64 0.625 MHz

2 x 20 MHz 2 x 128 0.156 MHz20 MHz 256 0.078 MHz


For the first three modes, the bandwidth is splitinto two adjacent bands. Typically 10% of thebandwidth is lost due to filter attenuation.

—For the next deadline, proposals may request thenew correlator. However, projects which make ex-plicit use of the capabilities of the new correlator maybe delayed if the installation is not done as planned.Projects which can be carried on with the currentcorrelator should be explicitly mentioned. Given theupward compatibility of the new correlator capabili-ties with the current system, they will be started withthe current system, and continued with the new one.

Stephane GUILLOTEAU

Receivers

Are We Getting Better Receivers Soon ?

The status of installed receivers is reviewed in the sectionsdevoted to each telescope. As for the current activities ofthe receiver group, if they prove successful, they will bereviewed in the same way in future issues of the Newslet-ter, or else we better keep quiet about them. So I willlimit my contribution to either receivers almost ready toship out, or to fairly general considerations.

CLOSED—CYCLE 3—MM RECEIVER

A 3-mm receiver incorporating several new features isscheduled for installation on the 30-m telescope in April1992. It uses a two-backshort mixer built by A. R. Kerr(NRAO) inside a MK4 cryostat using a closed-cycle cryo-generator (the prototype unit built by CENG). Besides,this receiver will be tuned through a remote control rack.

At the time of writing, the installation of the mixer inthe cryostat is complete. The mixer backshort drives hadto be rebuilt by the Grenoble workshop. The local oscil-lator is fed by a 20-dB cold waveguide coupler, designedand built by TRAM, and the signal is fed through a thinmatched window and a cold lens. SSB receiver tempera-tures below 100K have been measured.

The remote control unit, built in Granada, has been inGrenoble since September for testing and modifications. Ithas been successfully used to tune the new receiver. Somework remains to store tuning tables and automate sometasks, such as LO peaking. It is foreseen to ultimately usesimilar systems on all IRAM heterodyne receivers.

345 GHz SIS RECEIVER

A 345 GIlz SIS receiver has been tested at the telescopein November. This receiver was built by H. Rothermel

(MPE, Munich) using Nb junctions fabricated in TRAM.The main results areo TR,D S B r-Z,d 150 Ko Fef f = 0.7O Bel f = 0.17Therefore, the sky or main beam efficiencies are compara-ble to those of the Schottky 345 GHz receiver, while thereceiver temperature is a factor of four lower.

A separately available report is devoted to a full accountof these tests. The receiver has been returned to Grenoblefor improvement of the beam coupling. H. Rothermel isstaying in Grenoble until April 1992. 1.

RECEIVERS FOR PLATEAU DE BURE

The Schottky receiver of Antenna 2 will soon get a well-earned retirement when replaced with an SIS receiver.Some work is also needed on the two other SIS receivers.

After a long period of uncertainty, a solution seems tobe in sight with the Air Liquide closed-cycle cryogenera-tors. Work will resume on the second generation Plateaude Bure receivers, benefitting from the experience gainedwith the closed-cycle receiver ready to be shipped to PicoVeleta.

ONGOING RECEIVER DEVELOPMENTS

For the past 18 months, the receiver group has been im-plementing Nb junctions, first in the 3-mm band, thenin the 230 GHz band. A 2-mm Nb junction is ready fortesting. A better understanding of the mixers is gradu-ally being gained. In the 230 GEN band, a magnetic fieldmust be used to suppress the Josephson current whichotherwise creates excess noise. Flux trapping is more ofa problem with Niobium (a type II superconductor) thanwith Lead. Non-contacting backshorts of a new type arebeing evaluated, which might improve the reproducibilityof receiver tunings. New mixer structures incorporatinginductive tunings are being or will soon be tested.

Bernard LAZAREFF

Backends

Assembly of the new 30-m spectral correlators has endedby early December. Module and system testing werecompleted successfully. The real-time software and someglobal stability tests will be conducted until Christmas.Delivery is scheduled for the first days of January, 1992.The spectral capabilities of these two units will range from

1We are presently studying the possibility of making this receiver

available to guest observers as soon as possible. For details, pleasesee the call for proposals in this Newsletter.


4096 channels on 40MHz to 1024 channels on 1280 MHz.A User's manual has been written in August, 1991 and iswidely spread on the site. Copies are available from theIRAM Library under the reference 209/91.

The six Plateau de Bure correlator units (4 antennas,960 MHz bandwidth) will start to be integrated just af-ter the expedition of the 30-m ones. All the modules arealready built. Central parts (signal, time and frequencydistributions) are currently under design.

Marc TORRES

Computers

1991 has been an auspicious year for the computer groupwith new installations and various activities.

COMPUTING FACILITIES AT GRENOBLE

In July the computer and terminal rooms were rear-ranged. Now, in a spacious room with comfortable chairswe meet visitors accessing the large facilities as well andthe still demanding MAC users editing documentationswith their favorite personal computers.

However more important but less visible improvementshave been made: early this year a new microVAX 4000model 300 (IRAM04) was added to the VMS cluster. Itbecame the most powerful VAX/VMS server at TRAMwith 8 times the CPU performances of a VAX-11/780.It main features are 32 Mbytes of memory, a 1 GbyteDSSI disk and a 1.2 Gbyte SCSI extra disk. Now the VMScluster is composed of this new server plus 2 work stations(VS3200 and GPX), all running DECwindows. To achievethe integration of personal computers, printers, and ser-vices in general, PATHWORK for MAC has been addedand an improved version for PC has been installed. Thisintegration based on Ethernet thin wire cable connectionhas proved to be an efficient and valuable solution.

Meanwhile it has been decided to use a UNIX RISCwork station to reduce the interferometer data. Risc ma-chines are today the best price/performance solution forintensive calculations and fast scientific visualization. Af-ter an evaluation on different stations from several man-ufacturers with standard operations, including mappingand cleaning, an HP 730 has been selected and purchased.This machine will be offered in priority to the visitorscoming to Grenoble to process their data collected atBure. The HP 730 delivers 72 SPECmarks, 76 MIPS and22 MFLOPS. It has been purchased with 32 MBytes ofmemory, a 400 MByte internal disk and with DAT andCD ROM drives. The machine is on the way to be pro-posed to the users. Its customization includes the instal-lation of the well known editor EMACS, and tools such as

DECTERM to create X DEC terminal windows, NPRINTto use the VMS cluster printers, and facilities to createproject accounts.

Recently a HP 720 has been received. This machine,purchased with french funds to help interferometry im-agery and algorithm development, will be used by stafffrom TRAM and Grenoble Observatory. For both HP workstations, extra magnetic disks and writable optical diskdrives has been ordered. Raw and reduced data will bekept on optical disks (one per project) and magnetic fastdisks will serve mainly as scratch space.

PC users with Ethernet connection to the VAXes canrun X terminal emulation under DECNET. To sup-port various network protocols, larger color scale andfast window management, NCD X color terminals havebeen purchased and installed in some astronomer offices.With both DECNET and TCP/IP those terminals canserve directly X applications running on HP/UNIX andVAX/VMS.

Recently our computers have been connected toGRENET, the campus Ethernet network, with an accessto Internet. Our subscription to Fnet, the french branchof EUnet, give us the opportunities to send and receivemail messages through our address IRAM.GRENET.FR.

BACKEND AND RECEIVER CONTROL

Using VME has been a key decision for the TRAM de-velopment: this includes the spectral correlators and thetuning of the future receivers under microprocessor con-trol. For all VME micros the common features are the059 operating system, the C programming language,Ethernet-TCP/IP communications and NFS to providevirtual disks for the software development.

Most of the routines for the correlator acquisition, con-trol and preprocessing have been written and tested.Those routines include the connection between the 059micros and the filter and LO black box, the correlator con-figuration, the sampler level adjustment, the acquisitionsynchronized on external interrupts, the preprocessing asFFT and clipping correction, and the data transfer to theVAX. An operational version of the software for the 30-mcorrelator, based on specifications from Granada, shouldbe assembled and tested soon.

For the receiver control, the VME microprocessor isinterfaced to a bus already developed and used at TRAM-Granada. Written in C, elementary control of motors hasbeen achieved in continuous or in pulse mode. With thistechnique a module has been written to set and to phaselock the frequency of an local oscillator and the completeadjustment of a receiver will be tested as soon as a receiveris available for this purpose.

Alain PERRIGOUARD


Data Reduction Software andHardware

—Interferometer data reduction will now be moved tothe new HP workstation. One face of an optical diskwill be devoted to each interferometer project for per-manent storage, while the hard disks will be used hasfast scratch space for interactive data reduction. TheHP 700s workstations also share some disk space withthe main VAX-4000, which is connected to Plateaude Bure.

—Software upgrade to use the GILDAS software(GreG, CLASS, CLIC, and all tasks) on the HP 730has been going on since September. GILDAS is nowalmost fully operational, although some bugs maypersist in a few tasks.

The HP workstations are typically 5 to 15 timesfaster than the VAX 4000 for data reduction.

—The new GILDAS software is operational on VAX-VMS, IBM AIX (RS/6000 machines), and HP-UX(HP 700 series), and being ported on ULTRIX (DEC3000/5000). It provides nearly transparent access todata files (GILDAS images, CLASS and CLIC datafiles) in a heterogeneous network (VAX, IEEE hard-ware machines, little and big endians). It is upwardcompatible with the previous version of GILDAS (butnot downward).

This version will be released on the previously men-tioned machines middle January 1992. Adaptationfor SUN-OS (Sparc workstations) should be relativelystraightforward.

Siephane GUILLOTEAU


Scientific results

We plan to include in this section abstracts of new scien-tific results obtained with IRAM instruments. Abstractsshould be e-mailed to R. Lucas (lucaseiram. grenet . fr );figures may be included as long as they are sent inPostscript (or in the form of GreG ".vec" files).

Interferometric Observations of SiO v = 0 ThermalEmission from Evolved Stars

R. Lucas, V. Bujarrabal, S. Guilloteau, R. Bachiller,A. Baudry, J. Cernicharo, J. Delannoy, T. Forveille,M. Guelin, S.J .E. Radford

Abstract: Using the TRAM interferometer on Plateau deBure we observed the SiO v = 0, J = 2 - 1 emissionfrom the 0-rich evolved stars RX Boo, VY CMa, R Cas,

Cet, NML Cyg, W llya, R Leo, 1K Tau, IRC+10011,and IRC+10420, the carbon star IRC+10216, and the S-type star x Cyg. In the best studied examples, RX Boo,R Cas, x Cyg, and IK Tau, the flux distribution has cir-cular symmetry. The observations of the other objectsare also compatible with this geometry. The linear radii,at half power, of the SiO emitting regions in the 0-richand S-type Miras range from 1 to 7 10 15 cm. Such sizesare larger than those adopted in recent models for SiOthermal emission, but much smaller than CO diameters.For supergiants and IRC+10216, the emitting regions arelarger than for 0-rich Miras.

Except for IRC+10216, the source diameters do notvary with radial velocity. This is not the behaviour ex-pected for envelopes expanding with an almost constantvelocity, which would have a clear maximum at the cen-tral velocities, and shows that the terminal velocity is notyet attained at distances of the order of 5 10 15 cm fromthe star. We suggest that such a phenomenon is due tograin formation extending over a region comparable to theSiO emitting shell, which is much larger than previouslybelieved.

HCN in the center of the galaxy IC 342D. Downes, S. J. E. Radford, S. Guilloteau, M. Guelin,A. Greve, D. Morris

Abstract: We have mapped HCN(1-0) line emission fromthe center of the galaxy IC 342 with the TRAM interfer-ometer at 2.7" resolution. By comparing this HCN mapwith other molecular line maps of similar resolution, wehave made the first determination of molecular line ratioson a scale of 20 pc in a massive galaxy other than our own.In the five main clouds within 100 pc of IC 342's nucleus,the C0(1-0)/HCN(1-0) intensity ratio is 7 ± 2 and is atleast twice as high farther out in the mini spiral arms.In the central region, the line intensity ratios of 13C0(1-0)/11CN(1-0) and IleN(1-0)/N113 are both - 2. We havealso detected 3.4 mm continuum radiation near the centerof the galaxy at a level of 27 nay. Comparison with 15

and 24 Gllz maps shows the 3.4 mm continuum is free-free emission rather than thermal radiation by dust. Thenumber of ionizing photons is similar to that in our Galac-tic center. Since the free-free continuum is associated withonly one of the dense molecular clouds traced by the HCN,most of the molecular clouds in the center of IC 342 donot show any massive star formation activity. The gas inthe molecular clouds is probably heated by turbulent dis-sipation rather than starlight. Since both the HCN(1-0)and the far IR radiation come from much smaller regionsthan the 12 C0(1-0), the RCN is better correlated withthe FIR radiation than is 12CO 3 but neither IICN nor COtrace star formation. The global LFIR /M(112) ratio is onlyan indirect indicator of the efficiency of star formation inthe center of IC 342.

Isotopic abundances in carbon-rich circumstellarenvelopes : a further iteration on the oxygen iso-tope puzzleC. Kahane, J. Cernicharo, M. Gu6lin, J. G6mez-Gonzalez

Abstract: We have detected the (J=1-0) and (J=2-1)lines of the oxygen and carbon isotopomers of COin five dusty carbon-rich envelopes (CIT6, IRC+10216,CRL618, CRL2688, NGC7027) which represent evolutionstages ranging from early AGB to planetary nebula. TheC170/C 180 abundance ratios, assumed to equal 170/180in the gas phase, are found to be larger than 1 in thelast four envelopes, and a lower limit of 1 was derived inCIT6. The 160/170 and

160/180 ratios, which range re-

spectively from 250 to 850 and 300 to 1300, were derivedfrom measured 13C160/120.70 and nci60/12ci80 ra-tios, assuming a 12C/ 13C ratio for each source. The carbonisotopic ratio is derived in CIT6 and CRL618 from the op-tically thin lines of rare isotopomers of CS, a method pre-viously used for IRC+10216. For the two last envelopes,CRL2688, and NGC7027, we have derived a lower limitto this ratio from the CO lines. It can be noticed thatin the five envelopes, we measure 12C/ 13C ratios largerthan 30, i.e. significantly larger than previous estimatesfor CRL2688 and CRL618. The values of the oxygen iso-topic ratios measured in these five dusty envelopes arecompared with those obtained from infrared observationsin less opaque envelopes, and with the predictions of themodels of nucleosynthesis and dredge-up in the red gi-ants. The 170/180 ratios measured in these five dustyenvelopes appear similar to those obtained from infraredobservations in less opaque C-rich and 0-rich envelopes,i.e. 4 to 5 times larger than the remarkably constant valueobserved in the interstellar medium (Penzias 1981). Weargue that AGB stars with C-rich (or translucent 0-rich)envelopes cannot be the dominant sources of oxygen (andpresumably, more generally, of star processed matter) inthe interstellar medium.


Call for Observing Proposals onthe 30m Telescope

The next deadline for the submission of observing propos-als for the TRAM 30 m telescope is Monday February 3rd.Exceptionally, three types of proposals will be consideredseparately:

—proposals at 3 mm, 2 mm and 1.3 mm wavelength(to be scheduled between May and August 1992),

—spectral line proposals at 0.8 mm (to be scheduled inthe second half of March 1992),

—"key programme" proposals.

Roughly 1700 h of observing time are expected to beavailable for 3 mm-1.3 mm proposals and 200 h for 0.8mm proposals. One key programme will be started thissummer. Please, find below some relevant information aswell a proposal form for "ordinary" 3 mm, 2 thin, 1.3mm or 0.8 mm programmes. A special form for "key pro-gramme" is also attached to this Newsletter.

APPLICATIONS

Your applications should be addressed as usual to:

TRAM Scientific Secretariat30-meter Observing Proposal

300 rue de la PiscineF-38406 St Martin d'Ileres Cedex

FRANCE

All proposals should have reached the Secretariat by Mon--day 3rd, midnight. (Proposals sent by Fax will be ac-cepted, provided they arrive by that time in a readableform; fax (33) 76 51 59 38). Except for a duplicate sourcelist (see below), no proposal should be sent by e-mail. You(i.e. the Principal Investigator) will receive by return mailan acknowledgement of receipt and a proposal number.

To avoid the allocation of several numbers per proposal,send only one copy of your proposal, either by mail orby fax. In case your fax reaches us in time incompleteor unreadable, we will try our best to contact you (yourresponsibility, however).

Proposals will be processed only if they are submittedusing the enclosed proposal forms (note that the forms for"key" and "ordinary" programmes are different). Do notuse characters of too small size (smaller than 11 point),which could make your proposal unreadable if we had tofax it, e.g. to the members of the P.C.

"Ordinary" Programmes

In the title page, you must fill out the line "special re-quirements" if you request "service observing" or specificdates for time dependant observations (if there are peri-ods when you cannot observe for personal reasons, please

specify them here; beware, however, that they could be amotive for proposal rejection!).

We insist upon receiving with the proposal a completelist of frequencies corrected for source redshift (to 0.1 Gliz,unless your frequencies are confidential). You should spec-ify with which receivers you plan to observe. Note that theuse of the 2 mm receiver prevents that of the second 1.3mm receiver, 230G2, which, otherwise, can be used in par-allel with receiver 230G1 (see below).

If your source list is long (e.g. more than 15 sources),we would appreciate if you could e-mail a duplicate to oneof the following email-addresses:

—[email protected]—earn::"te130m@frgag51"—psi%0208038022556::b erjaud—iram04::berjaud

this will help us to keep up a computerized source list.The scientific aims of the proposed programme should

be explained in 2 pages maximum of text, plus one page offigures and tables. Proposals should be self-explanatory,clearly state the aims and explain the need of the 30 mtelescope. The amount of time requested should be care-fully estimated and justified (the receiver performancesare summarized below); it should include pointing, fo-cussing, and calibration checks and allow for receiver tun-ings (average 20 min per receiver).

In order to open the telescope to more scientists andto increase the likelihood of completion of accepted pro-grammes, we would like to judge independently the short,self-contained projects and the longer ones. We ask youtherefore to specify whether time is asked for a self-contained project (supposed to lead directly to a publica-tion) or for a part of a larger project on the TRAM tele-scopes. If time has already been given but turned out to beinsufficient, explain the reasons, e.g. indicate the amountof time lost due to bad weather or equipment failure; ifthe fraction of time lost is close to 100%, don't rewrite theproposal, except for an introductory paragraph. For con-tinuation of proposals having led to publications, pleasegive references to the latter.

0.8 mm Spectral Line Programmes

The high sensitivity reached during a test period, last De-cember, with a prototype 0.8 mm SIS receiver (built by11. Rothermel from the Max Planck Institut fuer Extrater-restrische Physik, Garching) has prompted us to reservein the second half of march 199ta 1.5 week—long sessionfor programmes mostly aimed at spectral line studies be-tween 330 Gllz and 360 GHz.

The overall performances of this receiver at the tele-scope were (see report [8]):

—Trec(DSB)_^.t 150 K

—Forward efficiency (coupling to the sky) = 0.7

—Beam efficiency 0.17

—Aperture efficiency 0.10

January 1, 1992 TRAM Newsletter 9

- IIPBW= 8.5"

—Instantaneous spectral bandwidth: 512 MHz.

This receiver, on loan from M.P.E., will be used instead ofthe Schottky 345 GHz receiver. The 0.8 mm SIS receiverwill be usable simultaneously with one of the two 1.3 mmreceivers. Depending on the configuration chosen after thefinal tests, the 3 mm SIS receiver will be available eithersimultaneously with the 0.8 mm receiver, or as an alter-native (in the latter case, it will take only one minute toswitch between the 0.8 mm and the 3 mm receivers). Notethat for practical reasons no 0.8 mm receiver will n4 beavailable before the Fall, outside the March session.

All proposals asking for this receiver should take intoaccount the difficulties (large error beam, marginal point-ing accuracy, critical focussing, aperture efficiency chang-ing with elevation) of operating the 30 m telescope below1 mm. They must include (or be coupled to) a backupprogramme at lower frequencies. Use the "ordinary" pro-gramme proposal form and check out the "345 SIS" box.

Service Observing

To facilitate the execution of a number of short (<10h), self-contained programmes, we start "service observ-ing" for some easy to observe (e.g. one single source) pro-grammes with only one set of tunings. The observing willbe made by the TRAM staff, according to a pre-submittedobserving plan (forms will be given when proposals areaccepted). Please, if you are interested by this mode ofobserving, specify it as a "special requirement" in theproposal form (TRAM will decide which proposals will ac-tually go into that mode). If you are located in Spain,France, or Germany, we will try to mail you, via IBER-PAC, TRANSPAC, etc..., the spectra.30m files in quasireal-time; this excludes any intervention during the exe-cution of the programme (see for more details below).

Key Programmes on the 30 m Telescope

One "key" programme, to be started during the next ob-serving period, will be accepted on an experimental ba-sis. As specified earlier (see the "Call for Ideas for KeyProjects at the 30 m Telescope" of October 16th, 1991) aprogramme will qualify as "key programme" if and onlyif it satisfies all of the following conditions:

—it is an important, well defined, timely scientificproject that requires >200 hours total observingtime;

—it is perfectly adapted to the 30 m telescope and thereceivers available;

—it is likely to stimulate a whole new series of smallerresearch projects;

—it will provide a database of fundamental scientificinterest to a wide community;

—the proposers convincingly explain how they will ac-quire the database and will control its quality; theyshould carefully evaluate the amount of observingtime needed, specifying the assumed weather condi-tions.

—the proposers guarantee immediate data reductionand transfer of the full data (raw and reduced) tothe TRAM archive after each observing session.

We expect that the selected "key programme" will be car-ried out by an open team having a very good knowledgeof the 30 m telescope and with members from several in-stitutes.

The scientific aims and practical aspects of the pro-posed programme should be explained in 10 pages of text,figures and tables.

LAST PROGRAMME COMMITTEE MEETING

One hundred and thirty 30m telescope programmes, em-anating from 240 astronomers from 14 countries werediscussed at the last Programme Committee meeting(November 1991). A total of 5700 hours of observing timewere requested.

Thirty-nine programmes were rated "A" (some withspecial conditions, however), 21 programmes rated "B,and 70 rated "C", the scale of programme merit de-creasing from "A" to "C". Taking into account mainte-nance and various technical activities (receiver installa-tion, VLBI test period), 2000 hours of telescope will beallocated to programmes rated "A" or "B". Some pro-grammes rated "A" will be reduced in time and onlypart of the "B" programmes will actually be scheduled.Eight additional programmes, emanating from the groupof MPIfR scientists participating to the construction ofthe 1.3 mm bolometer, were also examined and will bescheduled. Proposals using the bolometer will be sched-uled between February 24th and March 17th; the spectralline programmes from end of December till beginning ofMay (December, January and February schedules havebeen notified to the interested Pis; March, April and Mayschedules will be communicated shortly). If you have ques-tions, please contact Mrs. C. Berjaud at TRAM Grenoble.

RELEVANT INFORMATION ABOUT THE 30 M TELESCOPE

Receivers

1. 3 mm Continuum Receiver:A cooled single-channel Schottky mixer receiver isinstalled in line of the 4th mirror, behind the polar-ization rotator. This receiver can be used simultane-ously with either the 2 mm receiver, or the 0.8 mmSchottky receiver, or a guest receiver. With the newIF distribution box this receiver can be connectedto all backends. Its tuning band (70-100 GHz) andnoise characteristics are given in Fig. 2. The receiver

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is primarily used for pointing; switching between thisand the other receivers via OBS is fast. Continuumsources of > 0.8 J'y (at 86 GHz) and SiO masersources can be used as pointing sources: there areapproximately 120 such continuum sources and 15SiO (J=2-1,v=1) masers catalogued. The Schottkyreceiver is normally aligned within 2" to the otherreceivers.

2. 3 mm SIS receiver:This receiver has been equipped with a new Nb junc-tion mixer in December. Tests on the telescope haveshown the following behaviour (report of Dec. 1991available upon request —Pp:

—Tuning band: 86 - 116 GHz.- SSB receiver temperature in the lower sideband

(at standard reference plane, behind the polar-ization rotator): 200 K at 115 GHz and about150 K at the center of the band 90 - 108 GHz.

- USB rejections of >10 dB can be reached overthe band.

Beware of possible (weak) instabilities near 110-122GHz and always check your calibration on strong ref-erence sources (see TRAM line catalog and updates {1,5]). Beware also of possible interference of the "sec-ond" 1.3 mm receiver, 230G2, with this receiver whenoperating at harmonic frequencies (the two receiversreceive the same polarization; the interference will bea strong and narrow line).

A new 3 mm SIS receiver, equipped with a closed-cycle cryostat, will be installed on the telescope inApril 1992 (see page 4 of this Newsletter). This re-ceiver should be available for the next period andhave better performances than the present 3 mm SIS,particularly near 115 GHz.

3. 2 mm Receiver:The performance of this receiver is good, with goodtuning characteristics (rejection 8 dB, good repro-ducibility). Tuning range from 127 GlIz to 183 GHzwith SSB receiver temperatures below 150 K up to150 Gliz and increasing to 400 K at 177 Gliz (seeFig. 3).

4. 1.3 mm Receivers:

- 230G1This receiver (the "old" 1.3 mm receiver) isequipped with a Pb junction.The band is 208 - 270 GHz. A SSB tuning listhas been established and shows that SSB tun-ing with more than $ dB rejection is possibleup to approx. 250- GHz. SSB temperatures are200-250 K between 210 and 245 Gliz (see Fig.4 and report [2]).

- 230G2This "second" 1.3 mm SIS receiver has a Nbjunction mixer. It has been tested on the tele-scope in December and found to operate satis-factorily (see [9]), except for a leak, which madeit unavailable since Christmas, but which shouldsoon be fixed.

—Operating band: 216— 231 Gift—SSB receiver temperature: 200 K- USB rejection achievable: >10 dB

The two 1.3 mm receivers and the 3 mm SIS receivercan be used simultaneously. Beware, however, of pos-sible interference of 230G2's LO into the 3 mm re-ceiver. Note that the 230G2 receiver cannot be usedwith the 2 mm receiver. The 2 mm and 230G2 re-ceivers use the same control box; switching from oneto the other will not be straightforward and will notbe made upon request.

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Figure 4: Performance of the 230G1 SIS receiver

5. 0.8 mm ReceiverThe 350 GHz Schottky will not be available duringthe coming period. During the second half of March,a more sensitive SIS receiver, built by H. Rother-mel and on loan from M.P.E. will be operated, asnoted above. Please, check the "345 GHz SIS" circlein the proposal form if you want to use this receiver.Note that 345 Gllz receiver proposals will competetogether and that the telescope efficiency is relativelylow and the pointing accuracy marginally adequateat this high frequency (see [7]).

6. 7 mm VLBI ReceiverThe Schottky 7 mm receiver (provided by MPIfR)has a DSB temperature of 150-160 K and is installedat the "bolometer position" so that the 4 th mirrormust be turned before use. This receiver will not beused for non-VLBI programmes.

7. BolometerNo bolometer will be made available during this ses-sion.

General Points about Receiver Operations

Under the condition of the present staff in the re-ceiver group it is possible to have one receiver en-gineer/technician at the telescope, weekends included.Through this situation the receiver tunings of the 1.3, 2and 3 mm SIS receivers have improved; it does not mean,however, that this one technician/engineer is available for24 hours, as sometimes expected by observers. (Night-time tunings, for example, will continue to be made byoperators.)

In view of the non-reproducibility of some receiver tun-ings, time often lacks for keeping up to date the tuninglists. (A test tuning with rejection measurement may betime-consuming —half to one hour— at some frequencies,

where the receiver behaves poorly.) While waiting for eas-ier to tune receivers, we use bad or marginal weather forthe pre-tunings: please be cooperative and don't cling toyour observing time if weather is poor. Remote control,which will be installed in the course of 1992-1993 on allreceivers, will help to cut further down receiver tuningtimes.

Meanwhile, we urge the observers to restrict as muchas possible their frequency tuning lists and to send themearly to Granada and Grenoble. For late arrivals (less thana week in advance) there is no guarantee for a prior testof the requested tunings.

Remote Observing / Service Observing

The telescope is controlled by the operator, assisted bythe astronomer on duty, in the remote as well as in thelocal observing modes. The operator tunes the receivers(at least during night time) and is in charge of the su-pervision of the telescope; he has to leave occasionallythe control room. During this time the astronomer onduty takes over. Remote observations thus require twopersons at the telescope and are only possible for a lim-ited number of hours. For safety reasons, direct accessto the OBS/OBSINP telescope control programmes fromoutside is not allowed, except from TRAM Granada.

Remote observing using OBS/OBSINP is possible fromthe downtown Granada TRAM office, while keeping closecontact with the operator/astronomer-on-duty via e-phone or other means. The RED data are on display.Short (few hours) proposals can be carried out this wayby experienced observers.

Service observing, with the PI staying in his own in-stitute, is available. Observations are be made by the lo-cal staff (operator, helped by astronomer on duty or bya member of the investigator's institute present at thetelescope for his own observations). They should be re-stricted to a single set of tunings, to few source changes,and be limited to approximately 10 hours. We intend tosend the spectra .30m data-files and the two pages of theOBS monitor to Grenoble, Bonn, Meudon, and perhaps afew other places (not in the US, so far). This is a passiveway of observing, no direct interaction with the telescopethrough OBS being possible.

Backend

The spectral backend consists of 5 parts which can beindividually connected to any receiver.

—512 channels of 1 MHz (can be split into two halveson two different receivers);

—512 channels of 1 MHz (not splittable);—256 channels of 100 kHz (splittable into two halves

movable inside the 500 MHz instantaneous band-width, or connectable to two different receivers; oneof the halves can be connected to a spectrum ex-pander with expansion ratios: 2, 4 and 8).


—500 channel AOS; bandwidth 500 MHz; actual spec-tral resolution 1.5 MHz.

—512 channel autocorrelator; total bandwidth: 40, 80,or 160 MHz.

The new IRAM autocorrelator (two units, each of1024 channels, 500 MHz max. bandwidth, 10 kHz max.resolution) will arrive at Granada in January; tests andinstallation at the telescope will start immediately. Hope-fully, it will be available for astronomical programmessometime this spring.

Pointing/Focussing

Pointing sessions are made every one to two weeks; atpresent, the fitted pointing parameters yield an absolutepointing accuracy better than 3-4" (r.m.s.). We also tryto keep the receivers as closely aligned as possible (toabout 2"). Check of the pointing and alignment is how-ever the responsibility of the observers (use a planet foralignment checks). Normally, the focus position can bemonitored with the 3 mm Continuum receiver, which hasthe same focus as the other receivers (except for 230G2whose focus is off by 0.4mm — to be checked for each runon a planet, however).

Wobbler

Beam-throw: from 0 to 240" on either side of the source(avoid small amplitudes). Phase duration (standard): 0.5 sfor continuum, 2 s for line. Note that usually sky noise isnot significantly decreased by wobbling faster.

Calibrated Spectral Lines

We are continuing the calibration of line intensities instandard astronomical sources, started with the Mauers-berger et al. catalog (Astron. Astrophys. Suppl. 79, 217,1989). These include higher frequency line calibrations(e.g. 245 Gliz) and denser grid of calibration measure-ments near the CO rotational line frequencies. These cal-ibrations are made with precisely known rejections (seee.g. [2,9]).

Weather Statistics

An analysis of the meteorological conditions, measuredover 3 years at the 30 m telescope site, is available un-der request [10]. It shows that the zenith sky opacity at1.3 mm, recorded in 1991, has switched from a "winterregime" (average day+night opacityf"...d 0 . ) to a "summerregime" 0.5) at the end of May and back to the win-ter regime at the end of September. 230 GHz opacitiesas low as 0.15 were recorded at several occasions duringmid-summer nights.

1991 REPORTS AVAILABLE UNDER REQUEST

1 Receiver tests of the December 1990 technical periodM. Guelin, H. Hein, S. Liechti, J. Cernicharo (Jan.1991)

2 Receiver tests during the April 1991 technical periodS. Liechti, M. Guelin, H. Hein, A. Greve (June 1991)

3 Antenna test measurements at 350 GHz with theMPIfR bolometer E. Kreysa, H. Steppe, C. Thum,J. Baars, R. Chini, A. Greve, G. Haslam, A. Sievers(Aug. 1991)

4 Thermal effects on the azimuth and elevation en-coders J. Cernicharo, J. Penalver (Sept. 1991)

5 Antenna test measurements at 350 GHz with theMPIfR Bolometer E. Kreysa, H. Steppe, C. Thum,J. Baars, R. Chini, A. Greve, G. Haslam, A. Sievers(Sept. 1991)

6 Test of the 43 GlIz receiver H. Steppe, A. Greve, H.Hein, T. Kampf, C. Kompe, A. Schmidt (Sept. 1991)

7 Gain elevation curve and aperture efficiencies for theTRAM 30 m telescope H. Steppe, R. Mauersberger,A. Greve, D. Morris (Sept. 91).

8 Tests of a 345 GHz open structure SIS receiver atthe TRAM 30-m telescope H. Rothermel, A. Greve,H. Hein, B. Lazareff (Nov. 1991).

9 3 mm and 1.3 mm receiver tests during the Decemberllth-13th period M. Carter, H. Hein, S. Navarro, Y.Bortolotti, B. Lefloch, S. Liechti, A. Greve, M. Guelin(Dec. 1991).

10 Meteorological conditions measured at the IRAM 30-m telescope A. Greve, J. Penalver, W. Brunswig, B.LeFloch (Dec. 1991)

(Please write to Mrs. C. Berjaud, TRAM Grenoble)

Michel GUELIN and Albert GREVE


Call for Observing Proposals onthe Plateau de Bure

Interferometer

Observing proposals are invited for the IRAM Plateaude Bure Interferometer (PdBI), for May 1, 1992 to Au-gust 31, 1992. The deadline for applications is February3, 1992. The available frequency range will be 81 GIIz to116 GHz.

Details of PdBI and operations are given in the docu-ment "An Introduction to the IRAM Plateau de Bure In-terferometer". Proposers should read this document care-fully before submitting any proposal. The PdBI has un-surpassed sensitivity, but limited imaging capabilities andspectral line coverage. For spectral line projects, the max-imum bandpass is 80 MHz (128 channels), and the highestresolution is 0.078 MHz (5 MHz, 64 channels, or 10 MHz128 channels).

Proposals should be sent to:

TRAM Scientific SecretariatInterferometer Observing Proposal

300 rue de la PiscineF-38406 Saint Martin d'Heres Cedex

FRANCE

TRAM expects to schedule and complete a total num-ber of up to 8 new projects in this period, with an elapsedtime of two months between start and end of any givenproject. Selection will be based on scientific merit, tech-nical feasibility, and adequacy to the instrument.

For this 4th call for proposal, please note the following:

—Summer Time Period:Day time observations are almost impossible duringthis period, with the exception of point source de-tection, or sources with strong enough continuum forself-calibration. Relatively high average water vaporcontent may adversely affect observations at frequen-cies higher than 100 GHz. No BC configuration willbe accepted for frequencies higher than 100 GHz dur-ing this period.

—Scheduling period:Please note that the applications are for a specificscheduling period.

—Coordinates and Velocities:The interferometer will now operate in the J2000.0system. For best positioning accuracy, source coordi-nates MUST be in the J2000.0 system; position errorsup to 0.3" may occur otherwise.

Please do not forget to specify LSR velocities for thesources. For pure continuum projects, the "special"velocity NULL (no Doppler tracking) can be used.

—New CorrelatorWe plan to install the new correlator system during

this period. The old correlators will be decommis-sioned as soon as the new system is installed: theywill not be used in parallel with the new system. De-tails of the new system are given elsewhere in thisnewsletter.

Proposals which require the new system possibilitieswill be accepted, but may be delayed until the cor-relator is finally operational. Other proposals will bestarted with the current correlators, but will continuewith the new system once it is installed. This will ofcourse complicate the data reduction process. How-ever, as spectral resolutions are compatible, we donot expect this additional complication to be severe.

—Receivers:The two SIS receivers can be tuned in lower side-band with USB rejection of 4-7 dB. In this modesystem temperatures (7;.*) below 150 K for A#3, and200 K for A#1 (Trec 50 and 70 K respectively), arenormally reached below 100 Gilz. Higher rejectionsoffer no gain in sensitivity. Accordingly, observationsare preferentially done in LSB. If you want a double-sideband tuning (e.g. to observe one spectral line ineach band), please specify it.

This LSB tuning is not possible above 113 Gliz, andnot for the Schottky mixer (2-3 dB rejection may bereached however).

The Schottky receiver has relatively poor perfor-mance in the 93 to 105 Gllz band (Trec 160-200 KDSB). We plan to replace it by an SIS mixer in 1992,but we still have no definite schedule for this.

—Two Antenna Proposals:Because of normal antenna maintenance in summer,2 antennas only may be available for 3-4 weeks.Projects which can be carried out in such a mode(detection, flux measurements, or in general all non-mapping projects) may take advantage of this mode.

Sun Avoidance:For safety reasons, the sun avoidance circle has beenextended to 35 degrees. Please take this into accountfor your sources AND for the calibrators.

—Mosaics:The PdBI has mosaicing capabilities, but the point-ing accuracy may be a limiting factor at the high-est frequencies. Please contact S.Guilloteau in caseof doubts.

—Configurations (reminder):The standard configurations have changed slightly toallow an increase in sensitivity for the "compact"CD configuration. D1 has been modified to N20-E10-W05 instead of N20-E10-W12, and a D3 con-figuration (N01-N05-W05) has been added. D3 willbe necessary only for sensitivity limited observations(mostly CO).


Stephane GUILLOTEAU—Data reduction:Proposers should be aware of constraints for data re-duction:

• In general, data will be reduced in Grenoble.Proposers will not come for the observations,but will have to come for the reduction.

• Fixed time slots will be allocated to each pro-posals for data reduction, typically one monthin advance. We try however to keep the datareduction schedule as flexible as we can.

• IRAM may consider splitting the data reductionin two phases: intermediate calibration and finalmapping.

Data reduction will be carried out on the dedicatedHP workstation.

—Local contact:Depending upon the program complexity, TRAM mayrequire an in-house collaborator instead of the normallocal contact.

—Technical pre-screening:All proposals will be reviewed for technical feasibilitybefore going to the program committee. Please helpin this task by submitting technically precise propos-als. Scientific justification should be kept within 2pages. If proposals are submitted sufficiently in ad-vance, there may be time for interaction with pro-posers in case of technical restrictions.

—Non-standard observations:Please contact S.Guilloteau in case of doubt aboutnon-standard program feasibility.

Available documents of general interest to potentialusers:

—"An Introduction to the TRAM Plateau de Bure In-terferometer".

—"TRAM Plateau de Bure Interferometer: CalibrationCookBook".

- "TRAM Plateau de Bure Interferometer: MappingCookBook".

—"TRAM Plateau de Bure Interferometer: FrequencySetup"

—"CLIC: Continuum and Line Interferometer Calibra-tion"

More specialized documents available:

—"TRAM Plateau de Bure Interferometer: OBS UsersGuide"

—"TRAM Plateau de Bure Interferometer: AmplitudeCalibration"

—"TRAM Plateau de Bure Interferometer: Pointing Pa-rameters"

—"TRAM Plateau de Bure Interferometer: TroubleShooting Guide"


Position OpenRESIDENT ASTRONOMER IN GRANADA

Applications are invited for the post of a resident as-tronomer at TRAM-Granada, starting April 1s1, 1992. Thetasks involve:- maintenance, supervision and upgrading of the 30-mtelescope control software- development and implem.entation of software for newobserving modes and associated data aquisition- participation in the development and supervision of dataarchiving at the 30-m telescope- regular participation in the astronomer-on-duty serviceat the 30-m telescope to support guest observers- participation in test observations (pointing, calibration,etc.) and their analysis.

Resident astronomers are expected to pursue scientificprojects- either of their own- and/or in collaboration with other TRAM staff members- and/or in collaboration with outside groups.

The initial appointment will be for a period of 2 yearswith the possibility of a prolongation by 1 year.

The applicants should have a university degree inphysics or astrophysics. Experience in observational as-tronomy is required. The candidate should furthermorehave an interest and a basic knowledge in computer sys-tems and scientific software.

Applications should be submitted to the TRAM Direc-tion at Grenoble, as soon as possible, and no later thanFebruary 15th, 1992.

The IRAM Newsletter is edited by Robert LUCAS at IRAM-Grenoble (e-mail address: lucaseiram.grenet.fr )

TRAM Addresses:

—Institut de Radioastronomie Millimêtrique300 rue de la Piscine, Domaine Universitaire38406 St Martin &Hems Cedex, FranceTel: (33) 76 82 49 00 Fax: (33) 76 51 59 38

—Institut de Radioastronotoie MillimetriqueObservatoire du Plateau de Bure05250 St Etienne en Devoluy, FranceTel: (33) 92 53 85 20 Fax: (33) 92 53 85 23

—Institut° de Radioastronomia MillimetricaAvenida Divina Pastora 7, Nucleo Central8012 Granada, EspanaTel: (34) 58 27 95 08 Fax: (34) 58 20 76 62

—Institut° de RaclioastronomiaEstacion Radioastronomia. IRAM-IGN del Pico VeletaSierra Nevada, Granada, EspaliaTel: (34) 58 48 04 13 Fax: (34) 58 48 04 17

E-Mail Addresses:

- TRAM-Grenoble: usernameCIRAM.GRENET.FR , orthrough SPAN: IRA}I04::username or 17805: :username

—TRAM-Granada: usernameCIRALES, or through SPAN:IRAMEG: :username or 16494: :username

The username is generally the last name of the person to becontacted.

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