iram newsletter · 2 iram newsletter september 1, 1992 table 1: efficiency of the 30m telescope:...

IRAM Newsletter

Number 5 September 1, 1992

Contents

30m Telescope ......................................................... 1Receivers . 3Backends .

•

. • • • ......... • • 4VLBI. . • . ........... . .. . .

•.......

4Call for Observing Proposals on the 30 m Telescope 5Call for Observing Proposals on the Plateau de Bure

Interferometer ...................................................... 9Scientific Results ...................................................... 11New Preprints ......................................................... 13

30m Telescope

EFFICIENCY MEASUREMENTS

There have been repeated requests of efficiency dataof the 30-m telescope. Table 1 summarizes relevant datacollected from various reports made by various observers.The data are not taken in a homogeneous way, and refer

0.6 a a

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Frequency (GHz)

Figure 1: Aperture efficiency data for the 30m telescope

to different periods of time, different receivers and aper-ture illuminations, with possible adjustments of the sur-face since the reported measurements.

Figure 1 shows a plot of nA versus frequency. We willbe pleased to receive additional data determined by otherobservers.

ITALSAT 7mm HOLOGRAPHY

A successful 7mm holography measurement (7 mm VLBISchottky receiver of the MPIfR) using the geostationarysatellite ITALSAT has been made by D. Morris. Thismeasurement shows unexpected systematic surface (wave-front) deformations of unknown origin. The measurementmust be verified and the surface errors localized.

We are still unable to obtain orbit predictions fromItaly; the orbit of the satellite was thus determined bydedicated observations made at Yebes Observatory, Spain(A. Barcia).

CORRELATORS

The two IRAM correlators have been used since abouttwo months, without serious problems, in the mode of 20MHz bandwidth/ 2048 channels each. This configurationis from now on available for regular observations and canbe requested for in proposals. Work is in progress (G.Paubert, A. Sievers) to make the other bandwidth / res-olution configurations available. Typical results may befound in fig. 2.

3 MM VLBI OBSERVATIONS

The first 3mm VLBI observations were successfully madeon 7-10 July 1992 between the European stations at On-sala, Effelsberg and Pico Veleta.

The observations were made with the 3mm single chan-nel Schottky receiver (see Newsletter 3, May 1992, for alayout of the system), well known to observers at PicoVeleta as the "pointing receiver". The DSB noise tem-perature was typically 200 K. The receiver was equippedwith a circulator plate built by the MPIfR. This plate can

a

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2 IRAM Newsletter September 1, 1992

Table 1: Efficiency of the 30m telescope: summary of measurements up to 1992

Freq. Receiver 7713 77F riA Beam Ref. Date Comments(GHz) (II)

43 MPI Sch. 0.57 61 9 07/91 c) 85 0.65 0.90 2 06/9086 Sch. 0.60 0.53 27 1 8890 SIS 0.54 0.47 26 1 8890 Sch. 0.67 0.53 25.3 7 8690 Sch. 0.58±0.03 27 13 02/92 100? SIS 0.45 - 0.47 4 a), c)106 Sch. 0.57 0.50 22 1 88111 Sch. 0.56 0.49 21 1 88115? SIS 0.89 10 12/91 d)115 SIS 0.89 11 02/92115 Sch. 0.59 0.50 21 7 86 140 SIS 0.59 0.50 17 1 88147 SIS 0.84 11 02/92150 0.55 0.88 2 06/90

256-----STS-1- 0.74 11 02/92230 Sch. 0.55 0.27 13.5 1 88230 Sch. 0.47 0.25 12.3 7 86230 SIS 0.47 0.27 12.5 1 88230 SIS 0.27 4 a), c)230 0.45 0.90 2 06/90230 SIS 0.79 10 12/91230.5 SIS 0.90 0.26±0.01 11.6 3 03 91 Planets

0 om.250 bolom. 11.4 6 08/91250 bolom. 0.44 0.28 11 1 88265 SIS 0,36 0.21 10.8 1 88265 SIS 0.36 0.90 2 06/90345 SIS 0.15 0.09 10 12 02/92345 bolom. 0.09 7 (?) 7 86345 Sch. 0.18 0.10 8.5 1 88 elev 45345 0.20 0.84 2 06/90345 SIS 0.17 0.095 8.5 5 11/91350 MPI bolom. 0.06 8.4 6 08/91350 MPI Sch. 0.106 4,7 87350 MPE Sch. 0.14 4,8

b), c)elev. 55

Comments:a) " from various reports"b) beam map at 350 GHz givenc) gain-elevation curve givend) "low sidelobes", 3 measurements to obtain nF

References:1 D. Downes: 1989, in Introductory courses in galaxies evolution, eds I. Appenzeller, H. Habing, P. Lena, Springer Verlag. [data from1987-1988; no references for the values given in the paper]2 J. Cemicharo, G. Paubert, G. Butin, S. Sanchez, H. Steppe, S. Liechti and W. Brunswig: 29/06/1990, Report on astronomical tests of

the new distribution box for the 30m MI-IT [no references for the values given in the report]3 C. Thum: 21/03/1991, internal note, Aperture efficiency of the 30-m telescope [Derivation of these values after measurement on Marsand Venus]4 H. Steppe, A. Greve, R. Mauersberger, D. Morris, C. Thum Axial gain-elevation dependence of the 30-m MRT between 90 and 845 GHz:Aperture efficiency as a function of wavelength (summary of observations between 1986 and 02/91) [Give best fit for Ruze formula]5 H. Rothermel, A. Greve, H. Hein, B. Lazareff: 11/1991 Tests of a 345 GHz open-structure SIS receiver at the IRAM 30m telescope

6 E. Kreysa et al.: 08/1991, Antenna test measurements at 350 GHz with MPIfR bolometer, MPIIR memo no 727 J.W.M. Baars et al. : 1987, A&A 175,, 3198 W. Wild, Thesis9 H. Steppe, A. Greve, H. Hein, T. Kaempf, C. Koempe, A. Schmidt: Jul 1991 Tests of the 43 GHz receiver.10 M. Carter et al..: 1991 Tests Dec. 1991 report.11 measurements by J. Wink12 H. Rotherm.el et al.: 1992, internal report, in print.13 Observations from 09/02/1992; ti A derived form planets, W30H, NGC7027, NGC7538, K3-50A, 3C273.

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September 1, 1992 IRAM Newsletter 3

be switched "in no time" between LCP and RCP polar-ization — and this facility turned out to be importantduring the experiment in order to find fringes.

To be confident of a success of the VLBI observationswe have made a test to check the phase stability of thesystem: receiver — IF chain — VLBA terminal. The phasestability was found to be 10 — 20

0 with some larger

phase drifts during several minutes. We are preparing asimilar test for the 3mm and 1.3 mm RS receivers, to beused in future observations.

Some results of the recent 3mm VLBI observations arepresent below (page 4).

Albert GREVE

—20 0

501/11s, 591‘112

Figure 2: 30 m correlator spectra of the CS (J = 2 — 1)line in DR 21. Integration time was 2 minutes for eachobservation

Receivers

RECEIVER UPGRADES AT PICO VELETA

A new 3mm RS mixer, built and tested in Grenoble thisspring was installed at the telescope. The first IF fre-quency for the 3mm receiver was changed to 1.5 GHz.A cryogenic HEMT amplifier built by Yebes Observatorywas installed. The warm IF chain and first downconverterwere also replaced. Improvements in mixer design and IFnoise temperature result in a significantly better SSB re-.ceiver temperature across the 85-115 GHz range, compa-rable to the best performance available elsewhere on Thetelescopes. Despite the lower IF frequency, SSB tuning re-mains possible at most frequencies. Figure 3 shows theperformance of the 3mm receiver prior to the Aug 92 up-grade, as recorded during routine service (a) as well asafter the upgrade, as recorded during initial on-site test-ing (b).

The IF amplifier for the V-pol 230 GHz receiver wasreplaced with one having a lower noise temperature; theperformance has improved only marginally.

For either of these two receivers, the "pseudo-DSB"backshort setting, maximizing IF power, does not alwayscorrespond to equal sideband ratios. The initial value ofgi = Gi1G, at the pseudo-DSB setting, derived from lab-oratory measurements or from a specific procedure usingastronomical lines, should be taken into account when set-ting the receiver for a desired rejection gi.

A more detailed account of these measurements, andsome measurements of focus, error beam, and astigma-tism, can be found in the technical report by Carter et al.

Matthew CARTER,Jean-Yves CHENU, Hauke HEIN, Santiago NAVARRO,Michel GUELIN, Bernard LAZAREFF

3MM - On-Site TestsAug 92

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IRAM Newsletter September 1, 1992

Backends

We summarize here the status of the new correlators:

Previous 3MM Receiver - On-Site PerformanceApr-May 92 _

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—30 m Telescope:The software for the new autocorrelators has beenwritten and tested by G.Paubert and A.Sievers(page 1).

—Plateau de Bure Interferometer:Four units (160 MHz each) have been installed andconnected to the interferometer. The basic phase anddelay refreshing time has been reduced from 4 to 1second. The software is quite operational and allowssearching for small system effects. Two units are keptin Grenoble as targets for lab people who check andinvestigate the problems reported by PdB. A new airconditioning system has been installed to cool thecorrelator.

Marc TORRES

a

250

200

150

100

50

80 100 120Frequency

Trec SS/3

Figure 3: Performance of the 3mm receiver:a) prior to the Aug 92 upgrade, as recorded during routineserviceb) after the Aug 92 upgrade, as recorded during initialon-site testing

VLBI

First 86 GHz VLBI test with the IRAM 30m telescope:First VLBI detection of the quasar 3C454.3 at mm-wavelengths

High resolution studies of the sub-parsec scale radiojets of active galactic nuclei are only possible at mm- andsubmm- wavelengths, since most central regions are op-tically thick at cm-wavelengths. Imaging with sufficientdynamic range requires the participation of large, sen-sitive telescopes. Following the successful 43 GHz VLBItests using the 30 m telescope in September 1991 (TRAMNewsletter no. 1) and May 1992 (data now being corre-lated) we organized a first test experiment at 86 GHz on1992 July 7-10 (18 UT-6 UT) in close cooperation withthe mm-VLBI teams at MPIfR, (Germany) and OnsalaSpace Observatory (Sweden). VLBA/MkIII recording ter-minals at a bandwidth of 112 MHz were used at the 30mat Pico Veleta ("X"), the 100m at Effelsberg ("B"), andthe 20m at Onsala ("5"). Baseline lengths are rangingfrom 832 km (B-S) to 2511 km (X-S), yielding a resolu-tion of 0.14 milliarcseconds (lrn.a.s. 4.3pc at z=1.25[Ho = 100kmIsIMpc, qo = 0.5] is achieved with global"conventional" VLBI arrays at 5 GHz).

Ten active galactic nuclei were selected for the obser-vations on the basis of recent flux density measurementswith the 30m and the Plateau de Bure Interferometer inthe 86-115 GHz band (S3.3mm = 2 — 30 Jy), and mapsfrom high frequency VLBI campaigns (e.g. at 43 GM).The schedule was optimized to enable the investigationof both system performance and sensitivity limits under

Sep mber 1, 1992 IRAM Newsletter 5

varying atmospheric conditions, and structural informa-tion: a 15 min scan consisted of 6.5 min VLBI measure-ments and 8.5 min for pointing/calibration measurements,individual sources were tracked from 0.5 to 2 hours at dif-ferent interferometer hour angles. After initial checks thereceiver polarization was changed at Onsala (LHC to lin-ear) and Pico Veleta (LUG to RHC) to match the one ofEffelsberg (RHC) (a detailed technical report is in prepa-ration).

Preliminary analysis of the data (at present being cor-related at MPIfR) has revealed clear detections of severalextragalactic radio sources (e.g. 3C273, 3C279, 3C345,0528+134, NRA0530); for the first time the superlu-minal quasar 3C454.3 has been detected with a VLB-Interferometer at mm-wavelengths. These results alreadydemonstrate the drastic improvement of the sensitivityof mm-VLBI arrays by the use of large (Effelsberg) andsensitive mm-(Pico Veleta) radio telescopes. Further im-provements are expected by the use of an SIS receiverfor the next VLBI test with Pico Veleta. The 30m to-gether with 3-5 antennas and intercontinental baselineswill undoubtedly enable mapping with a resolution of 50p—arcseconds at A3mm - with unsurpassed sensitivity!

Cornelius SCHALINSKI (on behalf of the mm- VLBItesting team)

Call for Observing Proposals onthe 30 m Telescope

The next deadline for the submission of observing propos-als for the IRAM 30 m telescope is Friday October end.Three types of proposals will be considered:

—proposals for 3 mm, 2 mm and 1.3 mm wavelengthsusing heterodyne receivers (to be scheduled betweenend of December 1992 and April 1993);

—proposals for 0.8 mm wavelength, using a heterodyneSIS receiver (to be scheduled end of January or begin-ning of March 1993 ). The receiver will be either thenew 345 GHz receiver under construction at IRAM,or H. Rothermel's (MPE) receiver [8] which was al-ready at the telescope last winter. This latter receivercannot be operated simultaneously with the other re-ceivers.

—proposals for 1.3 mm wavelength using the MPIfRseven-channel bolometer [13] (to be scheduled inFebruary 1993).

Roughly 1400 h of observing time are expected to beavailable for proposals using 3 mm — 1.3 mm heterodynereceivers, 200-300 hours for proposals using the 0.8 mmSIS receiver, and 300-400 hours for proposals using thebolometer. Please find below some relevant informationas well as a copy of the proposal form.

APPLICATIONS

Your applications should be addressed as usual to

TRAM Scientific Secretariat,300 rue de la piscine,

F-38406 St Martin d'Héres, France.

All proposals should have reached the Secretariat by Fri-day October 2nd, midnight. (Proposals sent by Fax willbe accepted, provided they arrive by that time in a read-able form; FAX (33) 76 51 59 38). Except for a duplicateof the source list (see below), no proposal should be sentby e-mail. You (i.e. the Principal Investigator) will re-ceive by return mail an acknowledgment of reception anda 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).

To make the appraisal and the scheduling of your pro-posal easier, we ask you to use proposal forms of the en-closed model. Do not use characters smaller than 1 lpt,which would make your proposal unreadable if we had tofax it, e.g. to the members of the P.C.

On the title page, you must fill out the line 'special re-quirements' if you request 'service observing' or specific

6 IRAM Newsletter September I, 1992

dates for time dependant observations (if there are peri-ods when you cannot observe for personal reasons, pleasespecify them here; beware, however, that they could be amotive for proposal rejection!).

We insist upon receiving with proposals for heterodynereceivers a complete list of frequencies corrected for sourceredshift (to 0.1 GHz, unless your frequencies are confiden-tial). You should specify which receivers you plan to use.Note that the use of the 2 mm receiver prevents use of thesecond 1.3 mm receiver 230G2, which, otherwise, can beused in parallel with receiver 230G1 (see below).

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

—berj aud@ir am .grenet—psi%0208038022556::berj aud—iram04::berj aud

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

be explained in 2 pages of text, maximum, plus one pageof figures and tables. Proposals should be self-explanatory,clearly state these aims, and explain the need of the 30 mtelescope. The amount of time requested should be care-fully estimated and justified (receiver performance is sum-marized below); it should include pointing, focussing, andcalibration checks and allow for receiver tunings (on av-erage 20 min. per receiver).

If time has already been given to one project but turnedout to be insufficient, explain the reasons, e.g. indicatethe amount of time lost due to bad weather or equip-ment failure; if the fraction of time lost is close to 100%,don't rewrite the proposal, except for an introductoryparagraph. For continuation of proposals having led topublications, please give references to the latter. In allcases, indicate on the first page form whether your pro-posal is (or is not) the resubmission or the continuationof a previously submitted 30 m telescope proposal.

SERVICE OBSERVING

To facilitate the execution of short (<10 h) programmes,we propose "service observing" for some easy to observe(e.g. single source) programmes with only one set of tun-ings. The observing will be made by the TRAM staff, ac-cording to a pre-submitted observing plan (forms will begiven when proposals are accepted). Please, if you areinterested by this mode of observing, specify it as a "spe-cial requirement" in the proposal form (IRAM will decidewhich proposals will actually go to that mode). If youare located in Spain, France, or Germany, we will try toe-mail you, via IBERPAC, TRANSPAC, etc..., the SPEC-TRA.30M files in quasi real-time; this excludes any inter-vention in the execution of the programme (see for moredetails below).

PROGRAMMES FOR THE SEPTEMBER 1992 — DECEMBER1992 PERIOD

Eighty-seven 30m telescope proposals were submitted forthe deadline of June 1992. About 2/3 of them will actu-ally get time on the telescope, some, however, with lesstime than requested. The telescope schedule for Septem-ber and October is made; the programme Pis have beenor are notified. The November—December schedule will bepublished shortly; programmes using the IRAM bolome-ter [12] will be scheduled early December.

Principal Investigators of scheduled proposals receivewith the telescope schedule a Confirmation of ObservingTime form which we ask you to return, properly filled, byFax to IRAM Granada and IRAM Grenoble (attentionMrs. C. Berjaud). The list of frequencies to be observed(normally, the same as in the proposal) should arrive inGranada at least two weeks in advance. It is also onlyafter reception in Grenoble of this form than we will sendduly signed mission forms to those of you entitled to travelreimbursement.

If you have questions, please contact Mrs. C. Berjaudat TRAM Grenoble.

Note that the telephone number and FAX number ofthe Pico Veleta Observatory (i.e. The telescope site, notthe downtown Granada office) have changed:Tel: (34) 58-4842-11FAX: (34) 58-48-08-60

RELEVANT INFORMATION ABOUT THE 30 M TELESCOPE

Receivers

The following table lists the possible receiver combina-tions:

Receiver CombinationsReceivers 3-receiver 2-receiver 1-receiver3MM-SISKerr-3mmCont-3mm2mm230G1230G2Bolo-1Bolo-27mm-VLBI

* * *

3 mm Continuum Receiver A cooled 2-channel receiver,operating in 1-channel mode with a Millitech Schottkymixer, is installed in line with the 4th mirror, behind thepolarization rotator. This receiver can be used simultane-ously with either the 2 mm receiver or a guest receiver.

The Continuum receiver is primarily used for pointing;switching between this and the other receivers via OBS isfast. Continuum sources of > 0.8 Jy (at 86 GHz) and SiOmaser sources can be used for pointing checks; there are


approximately 120 continuum sources and 15 SiO (J =2--I, v = 1) masers catalogued. The Continuum receiveris normally aligned within 2" of the other receivers. It issufficiently phase stable for VLBI observations.

3 mm SIS receiver This receiver has been equipped witha new Nb junction mixer in August 1992. Its performancehas improved above 100 GHz and in particular at 115GHz, where the SSB receiver temperature is 80K. TheIF frequency of this receiver is 1.5 GII.z, and not 3.9 GHzas for the 1.3 mm and 2 mm receivers. When tuned for theCO 115.27 GHz line in the LSB, the oxygen 118.75 GlIzfalls in the USB: system temperatures are lower thereforewhen using a large (> 15dB) USB rejection. Tests on thetelescope have shown the following behaviour ([15]):

—Tuning band: 85 - 116 GHz.- SSB receiver temperature in the lower sideband (at

standard reference plane, behind the polarization ro-tator): 100 K below 94 Gib and about 80 K abovethat frequency. At and near 100 Gllz, the mixer can-not be tuned SS& USB rejections of >10 dB can bereached over the rest of the band.

Beware of possible (weak) instabilities near 100 GHz andcheck your calibration on strong reference sources (seeTRAM line catalog and updates [1, 10, 15]). Beware alsoof possible interference between the 'second' 1.3 mm re-ceiver, 230G2, and this receiver when operating at har-monic frequencies (the two receivers receive the same po-larization; the interference will be a strong and narrowline).

2 mm Receiver The performance of this receiver is good,with good tuning characteristics (rejection 8 dB, good re-producibility). Tuning range from 130 GHz to 180 GHzwith DSB receiver temperatures of 115 K to 150 K be-tween 130 and 160 Gliz and increasing to 250 K at 180G Hz .

1.3 mm Receivers

—230G1:

This receiver (the 'old' 1.3 mm receiver) is equippedwith a Pb junction.

The range is 208 - 267 GHz. The tuning list showsthat SSB tuning with more than 8 dB rejection ispossible up to approx. 250 GHz [2]. SSB temperaturesare 200-250 K between 210 and 245 GHz.

—230G2:

This 'second' 1.3 mm SIS receiver has a Nb junc-tion mixer. Its cooled stage IF amplifierwas replacedin August 1992 by a new HEMT, provided by theC.A. Yebes, and the receiver performance improved.It has been tested on the telescope in August andfound to operate satisfactorily, through, presently, ina limited frequency range (see [10 and 15]). Note thatat 230 GHz its noise temperature is 1.5 times lower

than that of 230G1 and that asking for simultaneous1.3 mm and 2 mm observations deprives you of thisreceiver.

—Operating band: 216— 234 GHz.—SSB receiver temperature: < 150 K.- USB rejection achievable: 10dB.

The new LO allows tunings above 234 GHz, but thereceiver temperature quickly degrades (e.g. 200 KDSB at 238 GM). We hope to exchange the mixer inDecember and to be able to extend the RX operatingband.

There are occasionally problems with starting the re-ceiver after a warm-up (tuning of magnetic field).

The two 1.3 mm receivers and the 3 mm SIS RX can beused simultaneously. Beware, however, of possible inter-ference of 230G2's LO into the 3 mm RX. Note that the23OG2 RX cannot be used with the 2 mm receiver. The 2mm and 230G2 RX use the same control box; switchingfrom one to the other will not be straightforward and willnot be made upon request.

0.8 mm Receiver The 345 GHz SIS receiver built by H.Rothermel (MPE, Munich) will again be made availablefor a couple of weeks, probably in January. The expectedperformances (see [8]) are:

—Operating band: 330 GHz - 360 GHz—DSB receiver temperature= 150 (up to 345 GHz)

170 K above- Feff= 0.7—Beff=0.17This receiver works only in DSB mode with an 1.5 GHz

IF.

7 mm VLBI Receiver The Schottky 7 mm receiver (pro-vided by MPIfR) has a DSB temperature of 150-160 Kand is installed at the `bolometer position' so that the 4thmirror must be turned before use. This receiver will notbe used for non-VLBI programmes.

Bolometer The MPIfR 7-channel 1.25 mm bolometer [11]will be available in February to external users for a periodof 2- 3 weeks. The seven horns are placed at the cornersand center of an hexagon with a corner-to-corner spacingcorresponding to 20" . Each channel has a sensitivity of

90 mJy s1/2 under very good weather conditions and aHPBW of 12".

This bolometer is normally operated by wobbling thesecondary mirror in azimuth at 2 Hz. As the array isfixed in Nasmyth coordinates, the orientation of the 7beams with respect to the sky and to the chopping direc-tion changes with elevation. Special software will be madeavailable at the telescope by the MPIfR for data reduction.Users should be aware that the reduction of 7-channelobservations is considerably more complex than that of

8 IRA M Newsletter September 1, 1992

single-channel data. Array data reduction can be doneonly on an IRAM PC with a program package which, atpresent, does not support sky noise reduction algorithms.

GENERAL POINT ABOUT RECEIVER OPERATIONS

We urge observers to restrict their frequency lists as muchas possible and to send them early to Granada and Greno-ble. For late arrivals (less than 2 week in advance) thereis no guarantee for a prior test of the requested tunings.

Remote observing / Service observing

The telescope is controlled by the operator, assisted bythe astronomer on duty, in the local as well as in the re-mote 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 way byexperienced observers. This mode of observation shouldbe requested at least 2 weeks in advance.

"Service observing" , with the PI staying at his home in-stitute, is also possible upon request for some programmes(of less than 8 hours, with only one set of tunings and fewsources or positions observed). Observations are made bythe local staff (operators helped by astronomer on duty orby a member of the investigator's institute present at thetelescope for his own observations). We intend to sendthe 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. For this type of observation,we request an aknowledgement of the TRAM staff mem-ber's help in the forthcoming publication.

Backend

The spectral backend consists of 6 parts which can beindividually connected to any receiver.

—The 1_1MHz filterbank, consiting of 512 channels of1 MHz (can be split into two halves and connectedto two different receivers);

—The L1MHz filterbank, consisting of 512 channels of1 MHz (not splittable);

—The 100kHz backend, consisting of 256 channels of100 kHz (splittable into two halves movable inside the500 MHz instantaneous bandwidth, or connectableto two different receivers; one of the halves can beconnected to a spectrum expander with expansionratios: 2, 4 and 8).

—The 500 channel AOS: bandwidth 500 MHz; actualspectral resolution 1.5 MHz.

—The LAUTO new autocorrelator, consisting of 2048channels (total band available: 20 MHz, 40 MHz, 80MHz, 160 MHz) or 1024 channels (total band: 320MHz, 500 MHz).

—The LAUTO new autocorrelator, identical toLAUTO.

The TRAM autocorrelators are being tested at the tele-scope and are available, presently with some restrictionsin the possibilities of configuration (e.g. one autocorrela-tor per receiver).

Pointing / Focussing

Pointing sessions are made every one to two weeks; atpresent, the fitted pointing parameters yield an absolutepointing accuracy better than 3" (r.m.s.). We also try tokeep the receivers as closely aligned as possible (to about2", however, alignment can be lost by unknown reason).Check of the pointing and alignment is the responsabil-ity of the observers (use a planet for alignment checks).Normally, the focus position can be monitored with the 3mm Continuum receiver. Note that 230 G2 and 230 G1have foci differing by 0.5 mm. Using both receivers, youshould carefully monitor the focus and choose a compro-mise value. Not doing so may result in broadened beams(e.g. HPW 15" and non-gaussian beams on one receiver[15].

Wobbler

—Beam-throw: from 0 to 240" on either side of thesource (avoid small amplitudes).

—Phase duration: (standard) 0.5 s for continuum, 2 sfor line.

Calibrated spectral lines

We are continuing a number of line calibrations at thehigher frequencies (2 mm and 1.3 mm, similar to theMauersberger et al. catalog) and calibrations for red-shifted CO lines. These calibrations are made with pre-cisely known rejections (see e.g. [2,9,10]).

REFERENCES

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


[3] Thermal effects on the azimuth and elevation encodersJ. Cernicharo, J. Penalver (Sept. 1991)

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

[6] Test of the 43 GHz receiverH. Steppe, A. Greve, H. Hein, T. Kampf, C. Kompe,A. Schmidt (Sept. 1991)

[7] Gain elevation curve and aperture efficiencies for theIRAM 30 m telescopeH. Steppe, R. Mauersberger, A. Greve, D. Morris (Sept.91).

[8] Test of a 345 GHz open structure RS receiver at theTRAM 30 m telescopeH. Rothermel, A. Greve, H.Hein, B. Lazareff (Nov 91)

[9] Meteorological conditions measured at the IRAM 30-m telescopeA. Greve, J. Penalver, W. Brunswig, B. LeFloch (Dec1991)

[10] IRAM 30-m telescope receiver tests in December1991S. Liechti, M. Guelin, M. Carter, H. Hein, S. Navarro,B. LeFloch, A. Greve (Feb 1992)

[11] Bolometer array testE. Kreysa, G. Haslam (May 1992 Newsletter)

{12} A facility bolometer for the 30m telescopeC. Thum, E. Kreysa, D. John, H.P. Gemuend, W.Brunswig, A. Greve, G. Haslam, R. Lemke, H.P.Reuter, M. Ruiz, A. Sievers, H. Steppe (Aug. 1992; seealso May 1992 Newsletter)

[13] Holography of the 30 m telescope in July 92D. Morris, A. Barcia, J. Garrido, H. Hein, G. Butin, A.Greve (Sept 92)

[14] Surface precision of the 30 m telescopeD Morris, A. Greve (Sept 92)

[15] Receiver tests during the August 1992 periodM. Carter, J.Y. Chenu, H. Hein, S. Navarro, A. Greve,M. Guelin (Sept 92)

These reports are available under request (see alsoprevious Newsletters). Please write to Mrs. C. Berjaud,TRAM Grenoble.

Michel GUELIN and Albert GREVE

Call for Observing Proposals onthe Plateau de Bure

InterferometerObserving proposals are invited for the IRAM Plateaude Bure Interferometer (PdBI), for Jan 1, 1992 to Apr30, 1992. The deadline for applications is Friday October2nd, 1992. The available frequency range will be 81 GHzto 116 GHz.

Details of PdBI and operations are given in the docu-ment "An Introduction to the TRAM Plateau de Bure In-terferometer". Proposers should read this document care-fully before submitting any proposal.

Proposals should be sent to

TRAM Scientific SecretariatInterferometer Observing Proposal

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

FRANCE

IRAM expects to schedule and complete between 10 to20 projects in this period, with an elapsed time of twomonths between start and end of any given project. Selec-tion will be based on scientific merit, technical feasibility,and adequacy to the instrument.

For this call for proposal, please note the following:

—Number of AntennasAntenna 4 will come into operation during the firstquarter of 1993. We anticipate that most of the newprojects will be carried out with 4 antennas.

—ConfigurationsThe exact scheme of configurations is not yet finalizedfor 4 antennas. However, the "CD" (compact) arraywill be obtained with 3 configurations, and the "BC"(high resolution) array with 4 configurations. We donot yet know whether BC and CD arrays will sharemore than 1 configuration. Accordingly, it is of theutmost importance that you specify the exactconfiguration (3C or CD) required.

—Scheduling periodThe scheduling period will most likely start late Jan-uary, to give time for antenna 4 commissioning andto finish previous projects with 3 antennas.

—Coordinates and VelocitiesThe interferometer will now operate in the J2000.0system. For best positionning accuracy, source co-ordinates MUST be in the J2000.0 system; positionerrors up 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 CorrelatorThe new correlator system will be available duringthis period. As a reminder, this correlator has 6independent units, each being tunable anywhere inthe 100-600 MHz band, and providing 4 choices ofbandwidth/channel configuration: 160 MHz/64, 80MHz/128, 40 MHz/256 and 20 MHz/256.

—ReceiversAll receivers can be tuned in lower sideband withUSB rejection of 5-8 dB. In this mode system tem-peratures (2-;) below 150 K for A #2 and A#3, and180 K for A#1 (Trec 45 and 55 K respectively) arenormally reached below 100 GHz. Higher rejectionsoffer no gain in sensitivity. Accordingly, observationsare preferentially done in LSB. If your 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 GHz,

—Sun AvoidanceFor safety reasons, the sun avoidance circle has beenextended to 35 degrees. Please take this into accountfor your sources and for the calibrators.

—MosaicsThe 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.

—Data reductionProposers should be aware of constraints for data re-duction:

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

• We keep the data reduction schedule very flexi-ble, but wish to avoid the presence of more than2 groups at the same time in Grenoble. Pleasecontact us in advance.

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

• CLIC has been modified to handle the new cor-relator data. The new version is upward com-patible with the previous, but the reverse is nottrue. Observers wanting to finish data reduc-tion at their home institute should obtain anupdated version of CLIC, which will be releasedin October.

Data reduction will be carried out on the dedicatedHP workstation.

—Local contactDepending upon the program complexity, IRAM mayrequire an in-house collaborator instead of the normallocal contact.

—Technical pre-screeningAll 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 observationsPlease contact S.Guilloteau in case of doubt aboutnon-standard program feasibility.

The documentation for the IRAM Plateau de Bure in-terferometer includes documents of general interest to po-tential users:

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

—"IRAM 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 are also available; they areintended to observers on the site (TRAM on-duty as-tronomers, operators, or observers with non-standard pro-grams):

—"TRAM Plateau de Bure Interferometer: OBS UsersGuide"

—"TRAM Plateau de Bure Interferometer: AmplitudeCalibration"

—"TRAM Plateau de Bure Interferometer: Flux Mea-surements"

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

—"TRAM Plateau de Bure Interferometer: TroubleShooting Guide"

Most of these documents are now available on the TRAMelectronic mail file server news s erveiram grenet . fr. In-structions for using the file server are given at the end ofthe Newsletter.

Stiphane GUILLOTEAU


Scientific Results

CO emission from radio quiet quasars: new detec-tions support a thermal origin for the FIR emis-sion

D. Alloin', R. Barvainis2 , M.A. Gordon3 , R. Antonucci41 DAEC, Observatoire de Paris, Meudon, France2 Haystack Observatory, Westford, Mass. 01886, USA3 NRAO, Tucson, Ariz. 85721-0655, USA4 Physics Department, Univ. of California at Santa Bar-bara, Cal. 93106, USA

Abstract: We report detections of CO emission fromthe radio quiet quasars and luminous Seyfert I galaxies0050 + 12, 0157 + 00, 0232 - 09, 0838 + 77, 1353 + 18,1434 + 59, and 1613 + 65, and upper limits in 5 others.The observations show the same correlation between COand far-infrared (FIR) luminosity, and between 60 - 100eum color temperature and the ratio LFIR/M(H 2), as haspreviously been found for luminous IR galaxies. Theseresults support thermal radiation from dust as the far-infrared source rather than synchrotron emission.

Because we have observed with two different telescopes(the NRAO 12m and the TRAM 30m), and in two differenttransitions (CO = 1 - 0) and CO (J = 2 - 1)), wehave been able to constrain source sizes in a few objects,One source, NGC 895, appears to be resolved by the 13"CO = 2 - 1) beam at TRAM. Three other sourcesmay be somewhat resolved by this beam, depending onassumptions about CO excitation.

Detection of an intergalactic molecular complex ?

N. Brouillet 1,2 , C. Henke12 , and A. Baudryl1 Observatoire de l'Universite de Bordeaux, 33270 Floirac,France2 Max-Planck Institut fiir Radioastronomie, Auf demHiigel 69, 5300 Bonn, Germany

Abstract: 12C0 J = 1 - 0 and 2 - 1 emission is reportedfrom a highly confined 20") region east of M81. Beingassociated with the M81 group of galaxies, the molecularcomplex (106 - 10 7Mo) is likely of intergalactic natureand may represent the missing link between the extendedHI clouds of high column density and the young dwarfirregulars observed in this region.

A survey for extragalactic HCN and HCO+

Nguyen-Q-Rieu l , J.M.Jackson2 , C. Henke13 , Truong-Bach', and R. Mauersberger31 DEMIRM, Observatoire de Paris-Meudon, Meudon,France2 Dept. of Astronomy, Boston University, 725 Common-wealth Ave., Boston, MA 02215, USA3 Max-Planck Institut fiir Radioastronomie, Auf demHagel 69, 5300 Bonn, Germany

Abstract: We have surveyed 15 galaxies for HCN andHCO+ J = 1 - 0 emission and detected HCN in 12 ob-jects and IMO in 11. Maps were made of 1C342, M51,and M83. Since the HON and HCO + lines require higherdensities than CO J = 1 - 0 for excitation, they probedenser gas. Strong HCO+ J = 3 - 2 emission has beenfound in NGC 253. Our new J = 1 - 0 detections alongwith the J = 3 - 2 data are used to estimate excitationtemperatures and optical depths. We find Tex P.-, 20 K forNGC253, and ", 10 K for M82 and IC342, which indicatesa substantially larger kinetic temperature and/or volumedensity in NGC253. The HON/HCO+ line ratio variesfrom 0.5 to > 4, independent of obvious star formationindicators. In M51, the inner spiral arms traced by COare detected in HCN. In this galaxy, the HCN emissionpeak does not coincide with the strongest CO peak, butis instead located at the center of the nuclear CO ring.The maps of HCN and HCO+ J = 1 - 0 emission towardIC342 are significantly different, especially at the periph-ery of the nuclear region. These results show that CO,HCN, and HCO + probe distinct physical regions.

The HCN and HCO + J = 1 - 0 emission is onlyweakly correlated with CO J = 1 - 0 emission in a sim-ilar beam, suggesting that either the dense gas contentor the HCN and HCO+ abundances vary from galaxy togalaxy. In starburst and Seyfert galaxies, the emission ofHCO+ tends to be more tightly correlated with that ofCO and with the non-thermal continuum emission of thecentral compact radio source. This indicates that the pro-duction and/or excitation of HCO + may be due to an in-creased ionization by cosmic rays in the nuclear star form-ing regions. The H1 2 *--*CN/n 13CN and 1112C0411113C0+

intensity ratios in IC342, NGC253, and M82 are compa-rable to the 12C0/ 13C0 ratios. This result is consistentwith chemical models in the case of low electron densityand weak line saturation.

Submillimeter spectrum and dust mass of theprimeval galaxy 10214+4724

D. Downes', S. J. E. Radford', A. Greve 2 , C. Thum', P.M. Solomon3 , and J. E. Wink'1 Institut de Radio Astronomie Millimetrique, 38406 St.Martin d'Heres, France2 Instituto de Radioastronomia Millimetrica, 18012Granada, Spain3 Astronomy Program, State University of New York,Stony Brook, NY 11794, USAIRAM Preprint 258, ApJ (Letters), in press

Abstract: We measured with the IRAM 30m telescope thecontinuum flux of the extremely luminous primeval galaxyIRAS 10214+4724 at a wavelength of 1.2mm. This is thelongest wavelength at which this galaxy's thermal contin-uum radiation has been detected; at z = 2.286, it corre-sponds to a rest wavelength of 370 pm. From the entirecontinuum spectrum, we estimate a dust temperature of80 K and from the optically thin radiation at 370 pm (rest

I I I I I

CO(8"45)

Observed Frequency (GHz)210.6 210.4 210.2

6-4

5

I '

10214+4724z = 2.286

•I1■I

41.■

MM."

11■■••

..•■•1

0

—500

105.4 105.3

1 i I I -

0 500

105.2 105.1

10214+47244 —z = 2.286

-1 " " I I .-

C0(32)

2 if1

01.•

I I I I I i I I 1 -

0 500Velocity 1ty Offset (Ian s)

Figure 4: CO in IRAS 10214+4724

—2

—500


frame) we find a dust mass of 2.5 x 108 h- 2 Mo. For the11 2 mass of 1 x 10 11 h- 2 Mo implied by the CO line lu-minosity, this yields a ratio of the mass of gas (11 2 + He)to warm dust of 500, which is surprisingly normal for agalaxy at z = 2.3. It is the same value as observed in thecentral regions of nearby luminous galaxies that have so-lar metallicity. The ratio of observed CO and 370 pm (restframe) luminosities in 10214+4724, essentially the gas todust mass ratio, is the same as in nearby galaxies. Hencein this galaxy, most of the heavy elements have alreadybeen produced, at nearly present-day abundances.

Warm molecular gas in the primeval galaxy10214+4724

P. M. Solomon', D. Downes2 , and S. J. E. Radford21 Astronomy Program, State University of New York,Stony Brook, NY 11794, USA2 Institut de Radio Astronomie Millimetrique, 38406 St.Martin d'Heres, FranceIRAM Preprint 259, ApJ (Letters), in press

Abstract: We observed CO(6 -05) and (3 -+ 2) emission atz = 2.286 from the extremely luminous infrared galaxy10214+4724. The CO(6 5) line traces warm molecu-lar gas, which is found in the Milky Way only in re-gions of high mass star formation. The molecular gas in10214+4724 is warm and dense with n(H 2 ) Pd.# 5000 cm-3if 21in = 50K. The total mass of molecular hydrogenM(H 2 ) = 1 x 10"h -2 Mo. Although this is about 200times less mass than initially estimated by Brown Sz Van-.den Bout (1991), it is still 3-5 times larger than the molec-ular mass of any other galaxy yet observed and 60h-2more than the H2 mass of the Milky Way. A starburstcan power 10214+4724 only if predominantly high massstars are produced. This extraordinary primeval galaxyhas most of its mass in molecular gas, has already col-lapsed, and is undergoing an extreme starburst that isgenerating metals in abundances close to solar.

CO Observations in NGC 604 : I. Physical Prop-erties

F. Viallefond l , F. Boulanger 2,3 , P. Cox4,5 , J. Lequeux1,2,M. Perault 2 and S.N. Vogel61 Observatoire de Paris, Section de Meudon, 92190Meudon, France2 Radioastronomie, Ecole Normale Superieure, 24 rueLhomond, 75231 Paris Cedex, France3 IPAC, Caltech 100 - 22, Pasadena, California 91125,U.S.A.4 Observatoire de Marseille, 2 Pl. Leverrier, 13248 Mar-seille Cedex 4, France5 Max-Planck-Institut fiir Radioastronomie, Auf demHiigel 69, D-5300 Bonn 1, Federal Republic of Germany6 University of Maryland, Astronomy Program, CollegePark, MD 20742, U.S.A.

Abstract: A field of one arcmin. diameter on the eastern

September 1, 1992 'RAM Newsletter 13

edge of the HIT region NGC 604 has been mapped in the(2 — 1) and (1 — 0) transitions of the 12 C0 molecule. Thedistribution of the CO emission, which is observed all overthat field, is characterized by two prominent concentra-tions plus a diffuse component with complex kinematics.The 13C0 molecule in the (2 — 1) and the (1 — 0) tran-sitions has also been observed. From these observations,the physical conditions (density, mass, temperature) ofthese concentrations are derived. Although NGC 604 isknown to be deficient in heavy elements as compared tothe metallicity in the solar neighborhood, the CO lumi-nosity to virial mass ratio is typical of those for GiantMolecular Clouds in our Galaxy.

S-bearing Molecules in 0-rich Circumstellar En-velopesA. Omont l , It. Lucas2,4 , M. Morris", S. Guilloteau2,41 Institut d'Astrophysique de Paris, CNRS, 98bis BdArago, 75014 Paris2 IRAM, 300, rue de la Piscine, 38406 Saint-Martin-d'Héres, France3 UCLA, Dept of Astronomy-156205, Los Angeles, CA90024, U.S.A.4 Observatoire de Grenoble, Universite Joseph Fourier,BP 53X, 38041 Grenoble, France

Abstract: Using the TRAM 30m telescope, we have carriedout a systematic survey of the millimeter line emission ofSO2 and H2 S in various categories of 0-rich circumstel-lar envelopes. The main sample contains 14 OH/IR starsof three classes: IRC objects with intermediate mass-lossrates, very cold OH/IR stars, and 011 supergiants. Threelines of SO 2 and two lines of II 2 S were observed. Bothmolecules were detected in all the stars, with multilinedetections in most of them. The J = 5 — 4 line of SiO,present in one of the observed frequency bands, was alsodetected in all objects. In addition, SO 2 was detected intwo SRb stars, and H 25 in the carbon star IRC+10216.Upper limits were obtained for the emission from 15 otherstars, both 0- and C-rich. The 86 GHz line of SO was alsodetected in 5 stars.

The lines of SO 2 are found to be optically thin with arelatively low rotational excitation temperature (25 — 40K), in good agreement with the chemical models predict-ing its photosynthesis in the outer layers of the envelope.The derived maximum abundances a few 10- 6 bynumber) also agree reasonably well with these models.

The apparent rotational temperature of 11 25 is inferredto be somewhat larger 50 — 100 K) and its line profilesappear somewhat narrower, suggesting a location of H2Sin inner layers of the envelope which have possibly notyet been fully accelerated. Models we have made for theinfrared rotational excitation shows that it is possible toaccount for the observational results with H 2 S confinedto the inner envelope with a relatively large abundance

10-5) and a cutoff radius of 10 16 cm. However, it isdifficult to give a satisfactory chemical account of such a

cutoff radius. It implies either a very low abundance of H(< 10- 5), or a synthesis of H 2 S on grains. The destructionof H 2 S much closer to the star than the destruction radiusof 11 20 is also difficult to explain by photodissociation orgrain processes.

The overall abundance of sulfur in the gas phase of 0-rich circumstellar envelopes is certainly relatively large,probably at least 50% of the solar abundance.

A few outstanding stars are discussed in terms of theirpeculiarities: the line profiles of the bipolar nebula OH231.8+4.2 are examined in terms of the pronounced bipo-lar structure and unusually high velocities within the flow,and the H2 S profiles in the supergiant NML Cygni arepossibly affected by the strong and anisotropic externalradiation field.

New Preprints

The following preprints are available from IRAM:

258. Submillimeter Spectrum and Dust Mass of thePrimeval Galaxy 10214+4724D. Downes, S.J.E. Radford, A. Greve, C. Thum, P.M.Solomon, J.E. Wink1992, Ap.J. (Letters) (abstract in this issue)

259. Warm Molecular Gas in the Primeval Galaxy10214+4724P.M. Solomon, S.J.E. Radford, D. Downes1992, Ap.J. (Letters) (abstract in this issue)

260. Dusty disks in the Multiple Systems UZ Tau andGG TauM. Simon, S. Guilloteau(abstract in Newsletter # 4)

261. Star Formation and Molecular Clouds in Blue Com-pact GalaxiesL.J.Sage, J.J. Salzer, H.H. Loose, C. Henkel

The following working report is available from TRAM

212/92 A Facility Bolometer for the TRAM 30-m Tele-scopeC. Thum, E. Kreysa, D. John, H.P. Gemiind, W.Brunswig, A. Greve, G. Haslam, It. Lemke, H.P.Reuter, M. Ruiz, A. Sievers, H. Steppe


The TRAM Newsletter is edited by Robert LUCAS at IRAM-Grenoble (e-mail address: lucaseiram.grenet.fr ).The IRAM Newsletter is available on electronic mail, by means of an electronic mail file server installed at IRAM. This fileserver is a file distribution service that uses electronic mail facilities to deliver files. To communicate with it you should senda message to the electronic address:newsservairam.grenet.frFor instance, to obtain a copy of the May 1992 issue, just send the one line message:SENDME MAY92.PSto the above electronic address. You will receive later a mail message containing the IRAM Newsletter in Postscript code.Please discard all the e-mail header information with a text editor, and send the file to a Postscript laser printer.More information may be obtained by sending the one line message:HELPWe also start to compile a list of e-mail addresses of IRAM users (e.g., in order to send warning messages when the Newsletteris available, but also to provide fast information, if needed). If you feel your address should be on this list, please send the oneline message:SUBSCRIBEto the following e-mail address:iramusers-requesteiram.grenet.frBoth addresses are valid on Internet, EARN-Bitnet and EAN .... Please keep R. Lucas informed of any problem you mayencounter.

IRAM Addresses:Address: Telephone: Fax:

Grenoble Institut de Radioastronomie Millimetrique (33) 76 82 49 00 (33) 76 51 59 38300 rue de la Piscine, Domaine Universitaire38406 St Martin d'Heres Cedex, France

Plateau de Bure Institut de Radioastronomie Millimetrique (33) 92 53 85 20 (33) 92 53 85 23Observatoire du Plateau de Bure05250 St Etienne en Devoluy, France

Granada Institut° de Radioastronomia (34) 58 27 95 08 (34) 58 20 76 62Avenida Divina Pastora 7, Nucleo Central8012 Granada, Esparta

Pico Veleta Institut° de Radioastronomia Millimetrica (34) 58 48 02 11 (34) 58 48 08 60Estacion Radioastronomia IRAM-IGNdel Pico VeletaSierra Nevada, Granada, Espana

E-Mail Addresses:

- IRAM-Grenoble: usernametIRAM.GRENET.FR , or through SPAN: IRA1104: :username or 17805: :username

—IRAM-Granada: usernameaIRAM.ES, or through SPAN: IRAMEG::username or 16494: :username

The username is generally the last name of the person to be contacted.

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