july 1998, number 25newslet/no25/naicno.25.pdf · ural test targets for the radar system, are fig....

The NAIC is operated by Cornell University under a Cooperative Agreement with the National Science Foundation.

July 1998, Number 25

not observable with the telescope in win-ter so it was not until May 9 that a suc-cessful detection of a planetary body,Mercury, was obtained. Two weeks lat-er on May 24 we made the first detec-tion of the small near earth asteroid, 4183Cuno and in June there were successfulobservations of another near earth aster-oid, 1994 AH2 (see Fig. 1). The first ob-

Planetary Radar AstronomyDon Campbell

The new S-band planetary radar systemhas been under test and developmentsince “first light” of the upgraded 305mtelescope in October, 1997. In late Oc-tober as part of these tests, an attempt

was made to detect Titan using the Areci-bo antenna to transmit and the 70-mNASA/JPL Goldstone antenna to receivethe echo. While unsuccessful, this at-tempt was a start in getting both the tele-scope and radar system operational.Unfortunately, Mercury and Venus, nat-ural test targets for the radar system, are

Fig. 1: The target, asteroid 1994 AH2, was believed to be about 2 km in diameter. The spectrum has a

narrower-than-expected bandwidth, suggesting either a smaller, very reflective object, or that its pole was

nearly pointed at us during this obsevation.

INDEX

Planetary Radar Astronomy 1Radio Astronomy Highlights 2The Mission of NAIC 2Atmospheric Sciences 6Ionospheric Interactions News 71999 Arecibo Heating Campaigns 8Project Phoenix comes to Arecibo 9Gregorian Pointing 9Proposal Status 10Policy for Large Proposals 10Teacher Workshop at Arecibo 11Summer Student Program for 1998 11The Passage to Nowhere 12Comings and Goings 12

For a long time the front page of this newsletter has been dedicated to the progress of the upgrade. Now you might be expecting us to saythat we have left those days behind us, and that the observatory is back to normal operations. Well, not quite. But we are confident enoughthat we now grace the cover and first pages with scientific results that say, for the first time in recent memory, “we are back in business.”– The Editors

Resolution = 0.019 Hz

Frequency – offset (Hz)

cro

ss s

ect

ion

(K

m )2

First spatially-resolved post-upgrade S-band radar observation.

NAIC/AO NewsletterJuly 1998, Number 25 2

servations with the new system of a com-et, a newly discovered one, C/1998 K5,were made on June 12 and 14 with aweak detection being obtained on the14th. Over the next few months therewill be observations of at least one morenear earth asteroid, 1987 OA, observa-tions of Mercury aimed at a more de-tailed study of the probable ice depositsin the north polar region and observa-tions of Titan, again in a bistatic modewith the 70-m NASA/JPL Goldstone an-tenna.

As of June, 1998 the new S-band ra-dar system is operational, and about fourtimes more sensitive than the old one,but it has not yet achieved it full designperformance. The antenna gain at S-band (12.6 cm wavelength) is currentlymeasured to be 72.0 db (7.3 K/Jy), ap-proximately 1.5 db less than the designvalue. The gain decreases by the expect-

ed 1db out to the maximum zenith angleof 20°. Adjustments of the pitch and rollof the dome will result in improved fo-cusing and, hence, gain. Reduction ofthe rms errors of the secondary and pri-mary reflectors should then bring thegain to its design value. The system tem-perature of each of the two polarizationchannels is close to 30 K, 5 to 10 de-grees above what can probably beachieved. This excess temperature isprobably due to small contributions froma number of sources, tertiary spillover,radiation from the lifting hole in the cen-ter of the primary reflector and higherthan expected receiver temperature. Thenew S-band transmitter is consistentlyputting out between 900 kW and1,000 kW of power. However, some re-medial work, such as better regulationof the klystron magnet power supplies,

would improve operational ease and re-liability.

In the area of data acquisition hard-ware and software much has beenachieved with some further work need-ed. One of the intentions for the new sys-tem was that it be highly automated toallow automatic switching back and forthbetween transmit and receive/data acqui-sition. This capability is especially im-portant when the round trip light time tothe object is less than one minute. Auto-mation of the system has largely beenachieved with coordinated control of thetransmitter, the dome receiver room ro-tary floor, the receive horn protectiveshutter, Doppler shifting of the local os-cillator and data acquisition. It worksimpressively well. CW runs, where amonochromatic wave is transmitted andthe Doppler broadened echo from the ob-ject received, are now almost routine withthe last requirement, frequency switch-ing to improve baseline subtraction,about to be implemented. Ranging ob-servations for delay-Doppler mappingand orbit determination are now possi-ble for time resolutions of one microsec-ond or longer via direct sampling throughthe radar interface. Routines to analyzethis data still need work. Higher timeresolutions needed for the mapping ofNEA’s will require use of the new radardecoder. The hardware for this device iscompleted, but final testing and integra-tion into the system still needs to be done.

Radio Astronomy HighlightsChris Salter

During the first four months of 1998,alignment work on the 305-m telescopeled to azimuth motion restrictions whichseverely limited the number of outsideusers that could be accommodated.However, at the beginning of June 1998,following a month of intensive commis-sioning, the telescope returned toscheduled-user operations during theprime night-time hours. The projects thatrepresent the radio-astronomy observingsince that date are reviewed here.

The Mission of NAICPaul F. Goldsmith and Daniel R. Altschuler

Following the recommendations of the 1997 Arecibo Users and Scientific Ad-visory Committee (AUSAC) we have prepared the following:

Mission Statement

The National Astronomy and Ionosphere Center enables research in theareas of radio astronomy, solar system radar astronomy, and atmospheric sci-ences by providing unique capabilities and state-of-the-art instrumentation fordata collection and analysis, together with logistical support to users.

NAIC initiates and supports progress in the above research areas by main-taining a scientific staff whose members develop individual research programs,provide assistance to visiting scientists, and extend available scientific oppor-tunities by developing and implementing plans for future enhancements to NAICfacilities and instrumentation.

NAIC strengthens scientific and engineering research potential by support-ing activities which provide undergraduate and graduate students with oppor-tunities to further their education. NAIC contributes to the general understandingand appreciation of science by initiating and participating in public educationand outreach programs.

Use of the Arecibo Observatory, operated by NAIC, is available on an equal,competitive basis to all scientists from throughout the world to pursue researchin radio astronomy, radar astronomy and atmospheric sciences. Observingtime is granted on the basis of the most promising research, as ascertained bypeer review of proposals by external referees.


µB(0)

< 24.8 mag·arcsec-2. The individu-al galaxies were detected between 1372and 1420 MHz, showing the identifiedobjects to range from nearby dwarf gal-axies to large, intrinsically fairly lumi-nous galaxies. Additionally, the colorsof the detected galaxies lie within –0.9< U–B < 1.0m, 0.2 < B–V < 1.7m, show-ing successful detections for galaxiescovering the evolutionary LSB galaxyspectrum, and representing the first-everradio detection of a red LSB galaxy.While most LSB galaxies are extreme-ly blue and HI-rich, the class of red LSBgalaxies might be the descendents offaded starburst systems which have ex-hausted their HI several Gyr ago. TheHI mass of these systems will be criti-cal in resolving their star formation his-tories. These observers also detectedseveral new dwarf galaxies in the 6,000–10,000 kms-1 range, important to largescale structure mapping, as well as de-tecting a couple of low-redshift Malinobjects.

In a related project, Jim Schombert(Oregon), JoAnn Eder (NAIC), George

HI in GalaxiesA completely new auto/cross-correlationspectrometer has been built for post-up-grade operations. For each polarization,this can process four spectral slices, eachof up to 50-MHz bandwidth, with 4096channels and 3-level sampling. Alter-natively, bandwidths decreasing by fac-tors of two down to 195 kHz can bechosen. In addition, it is possible to se-lect either 9-level sampling with band-widths up to 25 MHz, or full-Stokesparameter observing with 3-level sam-pling and 25-MHz maximum bandwidth.One innovation is that the observing pa-rameters of each spectral slice can bechosen independently. Despite the ad-vanced features of its design, we note thatthis spectrometer will serve only as an“interim” backend and will be replacedin a year or so by a “next-generation”correlator.

In early June 1998, Riccardo Giov-anelli (Cornell) observed nearby, in-clined spiral galaxies for which I-bandimages already exist. The measured HIvelocities are being used via the Tully-Fisher technique to estimate secondarydistances, the local density field beingreconstructed from the resultant peculiarvelocities. He pronounced himself im-pressed with the post-upgrade L-bandsystem, noting superb telescope point-ing, and praising the exact repeatabilitybetween ON and OFF source conditionsin position-switching schemes resultingin excellent spectral baseline stability.He notes that the correlator performedexcellently, the 9-level sampling optionallowing high dynamic range of inputsignal and making it very forgiving ofstrong in-band radio-frequency interfer-ence (RFI). He adds that, while the RFIenvironment has presumably worsenedduring the Upgrade hiatus, L-band ob-servations are of overall better qualitynow than pre-upgrade, thanks to systemimprovements. Spectral baselines areextremely flat and separate subcorrela-tor spectra join seamlessly, with mostspectra being usable without the need tosubtract a polynomial baseline.

Low surface brightness (LSB) galax-ies are both a significant contributor tothe total galaxy mass and critical to un-derstanding the distribution and forma-tion of galaxy types. Over the pastseveral years O’Neil, Bothun &Schombert (Oregon) have made a CCDsurvey for LSB galaxies lying primarilyin the direction of the Pegasus and Can-cer galaxy clusters. This is the first ex-tensive multi-filter (Johnson/Kron-Cousins U, B, V, & I) LSB galaxysurvey, and they have found over 120previously undetected galaxies with col-ors ranging from very blue through tothe first discovery of very red LSB gal-axies. Their Arecibo run in late June1998 was the first attempt at determin-ing the gas content and redshift of thesegalaxies. In 58.5 hr of observing, 27 gal-axies were detected using 5-min ON/OFF pairs. The detected galaxies havesizes in the range 10 < r

27 < 47 arcsec (or

scale lengths between 3 and 20 arcsec),inclinations from 20° through 85° (de-termined photometrically), and centralsurface brightnesses in the range 22.0 <

km/sec

Frac

tion

of T

8100 8300 8500 8700 8900

0.004

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Low Surface Brightness Galaxy

5 min. ON-OFF/OFF

Fig. 2: This figure shows the HI spectrum of a low-surface brightness galaxy (J584-18-16). This is part of a

search of extremely faint galaxies taken from the DPOSS. The double trace at the left-hand side of the plot is

the region of overlap between two adjacent subcorrelators; no baseline has been removed. (Courtesy of JimSchombert and JoAnn Eder.)


es were taken whenever telescope mo-tion was either not possible or restrict-ed. However, completion of the track andtrolley alignment work in early May1998, and the subsequent return to fullypointed operations, means that the up-grade searches are no longer consideredactive. It is estimated that by this pointthe surveys cover some 70% of the Areci-bo sky. However, the surveys will con-tinue to have an impact on astronomyoperations at the Observatory, with manygood candidates awaiting confirmationin the months ahead. Significantly, weestimate that a total of 100 pulsars havebeen discovered through Arecibo drift-scan surveys since 1990 when Wolszc-zan (Penn State) used this technique todiscover the two millisecond pulsars,PSR B1257+12 (that accompanied by itsown planetary system), and PSRB1534+12 (potentially the best labora-tory yet for research in relativistic phys-ics).

Early in June 1998, Duncan Lorimer(MPIfR, Bonn) and Kiriaki Xilouris(NAIC) began a deep pulsar search insupernova remnants (SNRs). They ac-quired data at 20 positions, with an aver-age integration time of 23 min on each.While most observations were made at430 MHz using the Carriage House, theyemployed L-band from the Gregoriandome for two of the SNRs. Data reduc-tion is underway at the Cornell TheoryCenter. Pulsars associated with SNRsare of great interest, and these observersare attempting to constrain the birth prop-erties of neutron stars. In addition, theyexpect to address the question of whatfraction of supernovae produce a neutronstar.

A consortium of observers from Ber-keley, Caltech, Jodrell Bank, MIT, NRL,Penn State, and Princeton continue theirregular post-upgrade timing observationof standard millisecond pulsars. To date,7 sessions have been observed, mainlyat L-band, with some half a dozen tar-gets being presently involved. Up to fiveindependent pulsar backends can nowcollect simultaneous data by tapping offof the same I.F., a feature used by the

scanned through ±7.5 arcmin in decli-nation in 3 min, with the correlatordumping independent spectra every 10sec (see Fig. 3). This represents the firstpost-upgrade on-the-fly data acquisition,the measurements confirming over 65%of the observed sources.

Schneider, Rosenberg, John Huchra(CfA) and Eder have begun a survey ofK-band identified galaxies from the nearinfrared 2MASS project and aim at test-ing the characteristics of galaxies in thenear infra-red relative to their 21-cm HIemission. The interesting comparisonhere is that starlight suffers little extinc-tion at K, and it is much less influencedby star-formation than optical bands.They used standard on-off observationsto study galaxies with a range of colors,luminosities, and extragalactic environ-ments.

PulsarsDuring the upgrade years, observationsfor the upgrade drift-scan pulsar search-

Djorgovski and Steve Odewahn(Caltech) are determining the redshiftand HI content of a test sample of newLSB galaxies identified from fields ofthe Caltech Digitized Second PalomarSky Survey (DPOSS). During the fewhours of observing assigned to date, 8candidates were detected (see Fig. 2 foran example). These detections of ex-tremely small (d ~15 arcsec), faint, gas-rich galaxies demonstrates that Areciboobservations will be critical for apply-ing the anticipated large DPOSS LSBcatalogs to tests of biased galaxy forma-tion, LSB galaxy evolution and dwarfgalaxy formation. The newly discoveredobjects would be too faint for efficientoptical redshift measurement.

Steve Schneider and Jessica Rosen-berg (UMass) have scanned approxi-mately 350 objects to derive moreaccurate declinations and flux densitiesfor galaxies originally picked up in anArecibo upgrade HI drift-scan survey.Whilst the telescope tracked the discov-ery right ascension of a galaxy, it also

0230+2757

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0

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Fig. 3: The figure shows the eighteen 10-sec records for a galaxy detected in the UMass upgrade HI drift-scan

survey. The present observing system has proved very stable and no baselines were removed from the spectra.The two polarizations are plotted on top of each other. This particular galaxy is located at 1013 kms-1 in the

plot, and is one of this team’s sources with no clear optical counterpart visible on the Palomar Sky Survey. The

other prominent features in the plot are 1410 and 1400 MHz interference at 2200 and 4400 kms-1 and galacticHI at 0 kms-1. (Courtesy Steve Schneider and Jessica Rosenberg.)


consortium to observe with four or fivebackends simultaneously. Initial resultsindicate that timing residuals achievedby the various backends are unprecedent-edly small, the many innovations in data-taking hardware providing significantimprovements over the pre-upgrade sys-tem.

On June 18 and 21, 1998, Don Back-er (Berkeley) and collaborators observedthe strong millisecond pulsars,J1713+0747 and B1937+21, simulta-neously at Effelsberg and Arecibo, withB1937+21 being observed at Arecibo onall nights from June 18 to 21. The coor-

dinated L-band observations were madethrough identical backends, and will beused to constrain the timing uncertain-ties due to propagation through the in-terstellar medium (ISM). The 1.4-GHztiming residuals for B1937+21 are ex-cellent. There may be a 100–200-ns sys-tematic hour angle effect and, if so,random-noise limited timing at 50 ns per2-min integration is obtained. Howev-er, there are a few aberrant points at the500-ns level which are not understood.The sensitivity to gain changes is negli-gible. The sensitivity to RF changes isvery significant and not constant; thisneeds further investigation.

Xilouris, Shauna Sallmen (Berkeley),Backer, and Andrea Somer (Berkeley)have begun 430-MHz polarimetry of alarge sample of millisecond pulsars.They have extensive calibration for gainand relative RCP/LCP phase and antici-pate a quality result. This extends thework done already by Xilouris and Sall-men to lower frequencies and will be im-portant in interpretation of the structureof millisecond pulsar magnetospheres.

Joel Weisberg (Carleton), Xilourisand collaborators have initiated L-bandmeasurements of the HI absorption spec-tra of distant pulsars. To make these ob-servations they used the new CaltechCBR backend. They will use their spec-tra together with a galactic rotation mod-el to kinematically determine the pulsardistances, which will themselves becombined with the dispersion measuresof the targets to derive the mean elec-tron density along the line of sight.These latter values will be used to cali-brate models of the galactic electron-density distribution.

In June 1998, Backer, Somer andXilouris explored the performance of thetelescope for high-frequency pulsar mea-surements. Their observations resultedin pulse profiles for the 1.5-ms pulsar,B1937+21, at 2.4 GHz, and for PSRB0540+23 at 5 GHz. Both profiles dis-play excellent signal-to-noise ratios (Fig.4 a-b).

VLBIArecibo has continued its support of the8-m orbiting antenna, HALCA, of theJapanese VSOP (VLBI Space Observa-tory Programme) Project. An L-band runon the quasar J1602+334 took place onJune 26, 1998, and fringes were detect-ed over the entire tracking pass to Areci-bo. The first Arecibo C-bandobservations with HALCA were madeon the quasars, J2212+239 andJ2139+143, on May 27 and 28, 1998.The NRAO 140-ft telescope at GreenBank also joined in. The data from thefirst of these runs has recently been cor-related, and strong fringes were found

B0540+023 at 5 GHz

chan

nels

Fig. 4: These plots show the pulse profile of a) B0540+23 at 5 GHz and, b) B1937+21 at 2.38 GHz. The datawere acquired through the Arecibo Berkeley Pulsar Processor (ABPP) on 21st June 1998. (Courtesy of Don

Backer.)

(a)

(b)

chan

nels

B1937+21 at 2.4 GHz


on both recorded channels for all base-lines. Although Arecibo C-band sensi-tivity is presently somewhat below itsdesign target, the signal-to-noise ratiosobtained were 1000:1 between Areciboand the 140-ft, 100:1 between Areciboand HALCA, and 20:1 between HAL-CA and the 140-ft. Correlation forJ2139+143 is awaited. Two further C-band runs on J1824+107 and J1329+319were made on July 7 and 8, 1998. Thetapes have been sent for correlation. Thefirst three of these C-band targets formpart of the VSOP Survey of the 5-GHzcontinuum emission from all flat-spec-trum extragalactic sources at b >10° with5-GHz flux densities greater than 1 Jy.

Success in Space VLBI is not, how-ever, the end of the good news in respectof VLBI and Arecibo. Early in 1997,NAIC submitted a consortium proposal(with NRAO as partner) to the NSF Ma-jor Research Instrumentation (MRI) pro-gram for the purchase of aVLBA-compatible system for Arecibo.Late in 1997, we received official con-firmation that the proposal had been suc-cessful. The MRI program requires thatcost sharing at the level of 30% be madeby the proposing institution, meaningthat of the total project costs of $502,000,about $150,000 will be provided by Cor-nell University. The equipment was or-dered early in 1998 and, when in placein early 1999, will enable the 305-m tele-scope to join in a wide range of VLBIobservations in conjunction withNRAO’s Very Long Baseline Array(VLBA), the global VLBI network, fu-ture Space VLBI antennas, and ad-hocarrays of the world’s largestfrequency-agile telescopes. In addition,Alan Rogers from Haystack Observato-ry has kindly supplied Arecibo with aphase calibration unit which will be usedin all future VLBI runs.

Atmospheric SciencesJonathan Friedman

World Day campaigns dominated atmo-spheric sciences activity during the past

three months. There were two notablesuccesses during this period. The firstwas coordination of the display of ob-servations over the world wide web withthe other National Science Foundation’sIncoherent Scatter Radar facilities. Thesecond was the implementation, for thefirst time since the start of the upgrade,of beam swinging with the ISR.

The first World Day campaign of thisperiod was April 27–29. It was a UARC(Upper Atmosphere Research Collabo-ratory) campaign in which SixtoGonzález participated in a demonstra-tion at the NSF in Washington. This wasthe first time that data from all of theNSF’s ISRs were available on the websimultaneously.

During May 26–27 we had a success-ful one day topside experiment. On June23–24 an important milestone in thecommissioning of the upgraded tele-scope was reached as we carried out thefirst beam-swinging experiment sincethe upgrade began. We did one 24 hourrun swinging the azimuth at half slew-rate (0.2 deg/s). The vector velocitiesobtained from this run are shown in Fig-ure 5. The three components shown arethe velocity parallel to the magnetic field

(Vpar), and the perpendicular north (Vpn)and east (Vpe) velocities. Although thisperiod was moderately disturbed, the ve-locities are in general agreement withtypical summer values, in particular thevelocity parallel to the magnetic field(Vpar) shows the usual post sunset col-lapse and large morning upward flow thatare two standard features of the summerionosphere over Arecibo. In addition,Mike Kelley from Cornell University hadtwo 5 hour observations during the nexttwo nights (see below) at full azimuthscan rate 0.4 deg/s or about 15 minutesper scan). The second of these nightswas quite disturbed (K

p=6+) and the

measurements show spectacular stormeffects on the ionosphere: increased tem-peratures around midnight and large ir-regularities in the density profiles. Afterthese succesful experiments we can safe-ly say that we are “back in business”.

Optical observations were made dur-ing all of the World Day observations.In April, nine nights of observations fromthe 21st through May 2 were carried out.Photometers recorded 78 hours of 630.0nm and 557.7 nm emissions along with65 hours of Fabry-Perot wind and tem-perature measurements from the sameemissions. The spectrometer operated

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Arecibo Ion Velocities June 23-24, 1998

Fig. 5: Ion velocities from 23-24 June, 1998. The three components shown are the velocity parallel to the

magnetic field (Vpar), and the perpendicular north (Vpn) and east (Vpe) velocities. The velocities are in gen-eral agreement with typical summer values.


80 hours in the red part of the spectrumrecording OH and O

2 emissions for me-

sospheric temperatures. Nine nights ofdata were also taken during the periodfrom May 19-21, although bad weatherand power outages caused some minorproblems. Finally, the airglow facilityoperated for ten nights during the JuneWorld Day period. Each instrumentlogged 80 hours. All of these data areawaiting analysis. During these periodsthe resonance lidar systems were idle,awaiting repairs of critical parts.

As mentioned above, the June WorldDay was extended to include 10 addi-tional hours of observing, this in supportof two field operations. One involvedcoherent scatter observations made bythe University of Illinois (Erhan Kudekiand Julio Urbina) and by Cornell Uni-versity (Wes Swartz) which were dedi-cated to sporadic E plasma instabilitystudies. The other was a tomographycampaign using the chain of stations onPuerto Rico (Gary Bust, Robert McCoy,Paul Bernhardt, and Daniel Meléndez)and an all-sky imager/GPS station set upby Cornell students (Francisco Garcia,Lymari Castro, and John Makela). Cas-tro is a former REU summer student atthe Observatory. She enrolled in thegraduate program at Cornell this sum-mer.

The first publication to come out ofthe Coqui Dos rocket campaign was justsubmitted to Geophysical Research Let-ters by University of New Hampshiregraduate student Lynette Gelinas. It isentitled “First observation of meteoriticcharged dust in the tropical mesosphere”and co-authored by Kristina Lynch ofUNH, Mike Kelley, Steve Collins, andSteve Baker of Cornell University, andQihou Zhou and Jonathan Friedmanfrom the Arecibo Observatory. The studyprovides the first observations of theearth’s mesopause dust layer using in-struments on Mike Kelley's SuddenAtom Layer rocket. This paper com-pared the dust observation with simulta-neously observed sporadic E andenhanced sodium layers. These datawere recorded with Arecibo's incoherent

scatter radar and sodium resonance li-dar. Steve Collins is compiling a CDwith all the sodium lidar and ISR datataken in the campaign. This will form alarge part of his thesis after he returns toCornell in the fall.

At the annual CEDAR meeting inBoulder, CO, June 7-12, Arecibo atmo-spheric science staff members played im-portant roles in three workshops.Jonathan Friedman worked with Rich-ard Collins (University of Alaska, Fair-banks) and C. Y. (Joe) She (ColoradoState University) to put together the two-part lidar workshop on Monday after-noon. This workshop was modelled onthe 1997 CEDAR ISR facilities work-shop. The first two hours was a plenarytutorial in which Jonathan gave the open-ing talk on the application of lidars tomiddle and upper atmospheric research.The second two hour session consistedof reports from the various facilities.Steve Collins reported on progress in li-dar work at Arecibo.

In another of the CEDAR workshops,Sixto González collaborated with PhilErickson (Millstone Hill) and Bob Kerr(Scientific Solutions) to convene a top-side workshop. The highlights (besidesthe premium time slot at 3:30 on Fridayafternoon) were Mike Sulzer’s talk onthe effect of electron collisions on theISR spectrum and Bryan Macpherson’sbrief presentation on observations dur-ing the February 1998 solar eclipse. Inaddition, there was discussion on hav-ing a topside workshop that may be host-ed at Arecibo.

At the Upper Atmospheric Facilitiesworkshop on Thursday, Craig Tepleygave an overview of atmospheric workduring the last year at Arecibo. This talkwas highlighted by results from the Co-qui Dos sounding rocket campaign andprogress on the upgrade. Of particularinterest was the upcoming World Daywhich, as we now know, was able to in-corporate beam swinging for the firsttime since the upgrade began.

Finally, in another CEDAR presen-tation Steve Collins combined with Brent

Grime, a former Arecibo REU summerstudent and now graduate student atPenn State, on a poster giving results oflidar observations of atomic layer en-hancements observed during the CoquiDos campaign. The study of these ALEswill form important parts of Steve’s dis-sertation and Brent's Masters’ thesis.

Ionospheric Interactions NewsBrett Isham

Collaboration with EISCATBrett Isham was principal scientific co-ordinator in a heating experiment car-ried out between June 5 and 15 at theEISCAT facility located near Tromso innorthern Norway. The principal objec-tives of the experiment were the studyof the microphysics of Langmuir turbu-lence during the first 100 ms after theturn on of the HF electromagnetic pumpwave and the physics of irregularitiesproduced during the heating process.EISCAT is a unique location for Lang-muir turbulence experiments due to thehigh HF effective radiated power (up to1.2 MW ERP), two incoherent scatterwave vectors (at 224 and 931 MHz), andthe near-field-aligned geometry (be-tween 0 and 13 degrees from parallel tothe geomagnetic field), all of whichcomplement very well similar experi-ments performed at Arecibo. Simulta-neous radio beacon scintillation andstimulated electromagnetic emission ob-servations were also performed and pro-vided valuable diagnostics on thebackground spectrum of plasma irregu-larities. During half of the heating ob-servations the HF duty cycle wasincreased and the irregularities becamethe primary topic of study, with the EIS-CAT radars providing valuable incoher-ent scatter support not yet available atother high latitude heating facilities.

This was the second EISCAT heat-ing experiment to be coordinated withsupport from Brett’s NSF/ONR Iono-spheric Interactions Initiative grant.Time on the EISCAT radars was con-


tributed by Tor Hagfors of the Max-Planck-Institute in Lindau, Germany,César La Hoz of the University of Trom-so in Norway, and Wlodek Kofman ofCEPHAG at Domaine University inGrenoble, France. The Max-Planck-In-stitute also contributed financial support,which helped to enable participation byFrank Djuth and John Elder of GeospaceResearch, Inc., whose work was support-ed by the Air Force Research Lab. Frankand John brought and operated their rawdata-taking system, which allowed tworaw data channels on each EISCAT ra-dar. The Air Force Research Lab alsoactively participated by performing ra-dio beacon scintillation and stimulatedelectromagnetic emission observations ata remote field site -- Keith Groves, BobLivingston, and Jake Quinn were respon-sible for those measurements. HF radarsupport during the first part of the cam-paign was provided by the British CUT-LASS SuperDARN radars in Iceland andFinland, operated by Terry Robinson andDarren Wright of Leicester University inthe UK. The timing of the experimentwas fortunate in that Pekka Hiitola of theGeophysical Institute in Sodankyla, Fin-land, offered to test a new raw data tak-ing system at the EISCAT 931 MHzremote receiving antenna in Finland,where the angle to the geomagnetic fieldis about 30 degrees, much closer to the45° angle at Arecibo and potentially veryinteresting for an EISCAT/Arecibo com-parison. Mike Rietveld, jointly of EIS-CAT and the Max-Planck-Institute, wasinvaluable in coordinating many of thedetails and through his operation of theheating facility and assistance in operat-ing the radars.

As noted above, the primary experi-mental objectives were Langmuir turbu-lence and irregularities. However,conditions in the auroral ionosphere varymarkedly from day to day, and not alldays were suited to the principal objec-tives. As a result, sufficient time wasavailable for several backup experiments,including natural plasma line observa-tions, support of satellite overpasses inthe hope of measuring auroral precipita-tion events, and meteor observations.

Specific results are not yet availableas the raw data has not been processed,but it is clear that, during the low dutycycle (100 ms on every 30 seconds)Langmuir turbulence experiment, the224 MHz (VHF) radar saw strong en-hancements looking 13 degrees awayfrom field-aligned, whereas the 931MHz (UHF) radar saw only occasionalvery weak enhancements at 13 degreesand saw much stronger and consistentenhancments at the field-aligned posi-tion, in agreement with past results. Itis a mystery as to why the UHF behavesin this fashion, and we expect the newdata to be of significant help in findingthe explanation.

1999 Arecibo Heating CampaignsMike Sulzer

In calendar year 1999 Arecibo intendsto conduct two ionospheric interactionscampaigns. The first of these will takeplace in the January/February time frameand the second in the mid to late sum-mer period. A decision has been madeto appoint a campaign scientist who willhelp coordinate the efforts by workingwith Mike Sulzer and John Harmon ofthe Arecibo Observatory and with the

user community. For the winter cam-paign Dr. Herbert Carlson will be thecampaign scientist and for the summercampaign Dr. Keith Groves will take onthese duties.

In the Active Experiments Newslet-ter it was announced that new proposalsmust be tendered for review to the Ob-servatory by August 1, 1998. We areextending this deadline to August 15.Emphasis will be placed on those exper-iments which can benefit most from win-ter ionospheric conditions and airglowobservations. There is a possibility thatthe scientists involved will be asked torelinquish time to a CEDAR/Wide Lati-tude Studies substorm campaign, shouldsuch an event occur during the heatingcampaign. As part of the campaign plan-ning we will incorporate contingencyplans for replacing hours lost due to mag-netic activity.

New proposals for the Summer 1999Campaign can be submitted at the sametime but must be submitted by October1, 1998. Emphasis will be placed on ex-periments which can benefit from simul-taneous coherent scatter radarobservations from Guadeloupe and/orsummertime ionospheric weather condi-tions.

The Project Pheonix Mobile Research Facility was recently located outside the transmitter room.

Photo by Tony Acevedo


Project Phoenix comes to AreciboChris Salter

Under a long-term commitment, ProjectPhoenix of the SETI Institute will recom-mence observing at Arecibo from Sep-tember 1998. In late 1992, as NASA’sHigh Resolution Microwave Survey,they used 200 hours on the telescope, ob-serving portions of the band between 1and 3 GHz on a number of Sun-like stars.No Extra Terrestrial Intelligence (ETI)signals were detected. In each of the nextfive years they will observe biannuallyfor 12 hr per day and 20 days per ses-sion. With this observing time they willsearch for ETI signals from a large num-ber of nearby solar-type stars.

Project Phoenix’s future observingtechnique will be very different to thepure single-dish approach employed pre-upgrade. Apart from doubling the band-width, they will now supplement theTargeted Search System (TSS) at Areci-bo with two Follow-Up Detection De-vices (FUDDs) operating pseudo-interferometrically at Arecibo and JodrellBank. For a narrow-band signal, the dif-ferential Doppler shift and drift betweenthese two sites pointing at the same ce-lestial position can be used as a filter toreject terrestrial or near-Earth RFI. A re-cent 16-week long campaign betweenthe Parkes and Mopra antennas provedthe system, though no potential ETI sig-nals were detected. Observations arealso being made using the NRAO 140-ftantenna and the Woodbury, GA, 30-mdish. Using Arecibo with 300-sec inte-grations, this team can gain a factor of20 in sensitivity over Parkes and GreenBank.

Because of limitations at JodrellBank at S-band, they will begin measure-ments at L-band. However, S-band ob-servations are also required for detectionof the beacon on the Pioneer 6 space-craft, used to check and calibrate the per-formance of the FUDDs. Up to the year2000, Project Phoenix will operate in theband 1.2 to 1.75 GHz, and the search willthen be continued in the 1.75 to 3 GHzrange.

The SETI search activity uses a Mo-bile Research Facility (MRF), a 30-ft by8-ft portable electronics shelter. TheMRF arrived at Arecibo recently, and isnow installed adjacent to the telescopecontrol room. It houses the necessaryback-end processing electronic equip-ment to support the project. In addition,the project’s own RF/IF up/down con-verter is now installed in the observingturret of the Gregorian Dome. Recently,SETI Institute staff have been on-site atArecibo preparing for the re-launch oftheir observations which will occur intwo month’s time.

Gregorian PointingMike Davis

The last shim bolt was tightened downon the azimuth rails in late April. Verti-cal alignment was improved from 3.6 to1.4 mm rms, the radial alignment is nowwithin 1.8 mm rms, and the average ra-dius is within 0.6 mm of its design val-ue.

These improvements set the stage fornew pointing measurements, which werecarried out in May. All measurementswere done at night, using the 2 arcminuteS-Band (2380 MHz) beam. Over 1,000“turret scans” were made of 23 unre-solved sources with very well knownpositions, spaced approximately everytwo degrees in declination. A turret scanallows the massive feed arm to tracksmoothly while the feed turret executesa sinusoidal motion with a period of 15seconds and amplitude of about 6 arc-minutes, see Fig. 6. The turret movesthe feed and receiver back and forthacross the focal point to shift the beamon the sky in the azimuth direction. Atthe same time the Gregorian Dome scans10 arcminutes in zenith angle. Each scanlasts two minutes, and provides an inde-pendent measurement of the azimuth andzenith angle pointing errors, sourcestrength, beam width in both coordinates,and relative system temperature.

Phil Perillat wrote the data acquisi-tion, processing and model fitting soft-ware. Mike Nolan contributed to the

Fig. 6: Turret Scan used to determine pointing corrections for the Arecibo telescope. While the massive feedarm tracks the nominal source azimuth and the Gregorian dome scans slowly through 10 arcminutes in zenith

angle, the antenna beam cuts through the source azimuth 16 times using 12 arcminute peak-to-peak sinusoi-

dal motion of the feed turret. Abscissa: Time, in tenths of seconds. Ordinate: Intensity (arbitrary units). Bothpolarizations are plotted.


development of the pointing model,which uses 13 free parameters in eachcoordinate. In addition, an ‘encoderfunction’ tabulated every half degree pro-vides an empirical fit to irregularities inthe elevation rail rack girder. The mod-el’s zero points are adjusted for eachfeed, to allow for small differences inmounting location, using turret scansmade for that purpose.

Figure 7 shows the results of testmeasurements following installation ofthe new pointing model. All of the ef-fort which went into precise alignmentof the rails has paid off. These residualshave an rms error of 3.7 arcseconds over-all, 2.2 in zenith angle and 3.4 in azi-muth. This is significantly better thanthe specification of 5 arcseconds rms ineach coordinate, and somewhat betterthan the residuals from the model fit of2.4 and 3.8 arcsec rms in zenith angleand azimuth, for a total of 4.5 arcsec.

A few cautions: these results obvi-ously apply only at night, and may de-grade with time. They do not yet takeadvantage of the improved platform sta-bility which will be provided by thetiedowns when we activate their comput-er control. Nevertheless, the present re-sults are significantly better thanexpected, and are a tribute to the carefulalignment work being carried out by JoseMaldonado and his staff in the Mainte-nance department.

Proposal StatusDaniel R. Altschuler and John K.Harmon

With a total current time request sinceFeb 1, 1997 of over 10,000 hours dis-tributed over 170 proposals we are cur-rently heavily oversubscribed. Only asmall fraction of all proposals will re-ceive telescope time during 1998, con-sidering also that a significant fractionof time is being used for commission-ing activities and adjustments to the tele-scope to improve performance.

We have extended the validity of cur-rent proposals as explained in the previ-ous newsletter so that proposalssubmitted for the 1997 deadlines (num-bered from 1000 to 1114) are valid forscheduling until Dec. 15, 1998. If notscheduled by then they will no longerbe considered. You will need to resub-mit proposals to keep them active.

All proposals submitted for 1998deadlines will be treated according to ourstandard procedures. If a proposal doesnot get scheduled in the first four-monthperiod because of lack of available tele-scope time, it will remain in the active-proposal category for the next period(unless the proposer withdraws the pro-posal). It will compete with all new pro-posals received by the next deadline. Ifa proposal fails to be scheduled after thesecond try, it will not be considered fur-ther. Proposers might then wish to sub-mit a revised version for a new deadline.

We will soon have the schedulesposted on the web so that you may bebetter informed.

Policy for Large ProposalsDaniel R. Altschuler

Our policy for Large Proposals followsthe recommendations of the report of theNRAO large proposals committee. Yourcomments are welcome at this time.

The narrative of a large proposal canbe up to 12 pages long. All proposalsthat ask for more observing time than

300–400 hours and, at the Director's dis-cretion, some proposals requesting lesstime than this, will initially be evaluatedby an expanded “skeptical review” pan-el of five or more referees. The panel willbe drawn from the normal pool of pro-posal referees for the telescope, augment-ed if necessary by others who haverecently been proposal referees. The pan-el will be roughly balanced between “ex-perts” in the sub-discipline addressed bythe large proposal, and cross-disciplinary“skeptics”.

The panel will assess:• the scientific priority for the propos-

al in competition with all other sci-ence that is being done at thetelescope,

• whether the telescope is well suitedto the proposal,

• whether the total duration proposedfor the project is well-defined andcommensurate with the scientific pri-ority,

• whether there should be any propri-etary “holding time” for the data, and,if so, for how long,

• whether the proposal is suitable foruse as a backup project in a dynamicscheduling strategy for the telescope.

The panel will provide the Directorwith a recommended course of actionand a summary of its deliberations.

Volunteering for Skeptical ReviewProposers of “moderate-sized” (below-threshold) projects may also volunteerfor expanded “skeptical review” of theirproposals. This option provides a way toobtain a stronger guarantee of observingtime for moderate-sized projects whosescience could clearly be advanced by re-ceiving such guarantees, in return forsubmitting them to a more demandinginitial review. We emphasize that we seethis as an option to be used rarely, andonly in exceptional cases where the sci-ence would suffer if the project was donepiecemeal through the regular proposalprocess.

Combined AZ and ZA error (arcsec)

Nu

mb

er

of

sam

ple

s

Test of new S-Band pointing model 28–29 May 1998

00

5

10

15

20

25

30

2 4 6 8 10 12 14 16

Fig. 7: Distribution of measured pointing residuals,

following installation of the new pointing model. Thestandard deviation is 3.7 arcseconds, with a 95th per-

centile value of 7.7 arcseconds.


Ongoing “Expert Review”The skeptical review panel for a largeproposal should also advise the Directorwhether any further “expert” review ofthe proposal is needed in any of the fol-lowing four areas:

• scientific issues of observing stra-tegy,

• technical issues of observing stra-tegy and data acquisition,

• ongoing review of project progress,and

• public availability of the data pro-ducts.

Not all large proposals will requirefurther review in all of these areas, andmany may not require further review atall. If a highly-rated large proposal is ofsufficient scope or technical complexityto warrant ongoing review, the NAIC willmake every effort to achieve this with-out over-burdening either the proposersor the expert referees. The arrangementsfor any ongoing “expert review” wouldbe made at the discretion of the Directoron a case-by-case basis.

If several large proposals are highlyrated by the skeptical review panels, theDirector will seek advice from across-disciplinary subset of the regularproposal referees about upper limits tothe fraction of all observing time thatshould be devoted to them.

First Teacher Workshop takes placeat AreciboDaniel R. Altschuler

One of the stated objectives of the An-gel Ramos Foundation Visitor and Edu-cational Facility was to “help to improvescience teaching in the public and pri-vate schools of Puerto Rico.” Towardthis end a proposal was successfully writ-ten to the Puerto Rico Department of Ed-ucation to provide funds for teacherworkshops. This summer two one-weeklong workshops led by José Alonso wereheld for a total of fifty teachers from thenorth-central area of Puerto Rico. Theworkshops provided hands-on activities

in the areas of weather, the moon, oursolar system and the constellations. Italso included a tour of the observatory,a “star party”, and a talk by one of ourscientists.

We hope to extend this program toteachers from all of Puerto Rico once wehave a larger VSQ.

Summer Student Program for 1998JoAnn Eder

The Observatory is hosting ten studentsfrom universities in Puerto Rico and themainland for ten weeks of research andstudy. This summer, the Arecibo Sum-

mer Student Program also includes ateacher from a local middle school whois working on developing classroom ma-terials in Spanish at the Visitor Center.She and the other summer students arebusily preparing for their own observ-ing time with the new Gregorian system.The students have designed four very in-teresting research programs which in-clude observations of radio continuumsources, spiral galaxies, OH/IR stars(evolved stars with circumstellar shells)and regions of star formation. In addi-tion, the students are working on re-search projects in radar and radioastronomy and atmospheric physics withtheir advisers.

Participants in the 1998 AOVEF Teachers’ Workshop.Photo by José Alonso

The 1998 Arecibo Observatory Summer Students. Pho

to b

y To

ny A

ceve

do


The 1998 NAIC summer studentsare: Angel Alejandro (UPR -Humacao),Monique Aller (Wellesley), Yira Corde-ro (UPR -Humacao), Ingrid Daubar(Cornell), Simon DeDeo (Harvard),David Kaplan (Cornell), Dale Kocevski(U. of Michigan), Myriam López (Moro-vis Middle School), Felix Mercado (U.Metropolitana), Benjamin Oppenheimer(Harvard), and Celia Salmerón (U. ofHouston).

The Passage to Nowhere GoesSomewhereDaniel R. Altschuler

As reported in the February 1996 News-letter, the new hallway to the controlroom area was inaugurated as “phaseone” of the control room modificationproject with a lot of fanfare in January1996. Until recently however this hall-way was a passage to nowhere, since assometimes happens, “phase two” had tobe delayed until we found the resources

Construction on the Control Room extension.

to do it. I am pleased that we are nowmore than half-way into completion ofthe control room expansion which we ex-pect to be ready by early September.

The new addition will provide roomfor user instrumentation, office space fortelescope operations and RFI coordina-tion work, office space for the mainte-nance department and a control roomannex with a small kitchenette.

Comings and Goings

New Astronomy PostdocsNAIC have recently awarded post-doc-toral research associateships to twoyoung radio astronomers. The CornellUniversity post-doctoral position atArecibo will be filled by Duncan Lorimerfrom the MPIfR, Bonn. Karen O’Neilfrom the University of Oregon will alsobe joining us at Arecibo as a post-doc.They will both be arriving in Puerto Ricothis October.

Duncan Lorimer hails from Darlingtonin the north of England. After studyingundergraduate astrophysics at the Uni-versity of Wales, Cardiff, he moved toManchester University, and the NuffieldRadio Astronomy Labs, Jodrell Bank, topursue his post-graduate studies. Therehe obtained his Ph.D. in 1994, havingwritten a thesis entitled, “The GalacticPopulation of Millisecond and NormalPulsars” under the supervision of An-drew Lyne, Dick Manchester and Mat-thew Bailes. For part of this time, he usedthe Parkes telescope intensively as amember of the Parkes Southern Sky Pul-sar Survey team. From late 1995, Dun-can has worked in the pulsar group at theMPIfR, Bonn, continuing his work onpulsar statistics and pulsar search, as wellas being involved in a number of collab-orative projects as part of the EuropeanPulsar Network (EPN). The latter in-cludes the simultaneous observation ofindividual pulses at a variety of frequen-cies. Duncan came to Puerto Rico for thefirst time this June to participate in apulsar search project with Kiriaki Xil-

Photo by Tony AcevedoAnother angle on the Control Room construction.

Photo by Tony Acevedo


You can find the electronic version (PDF) of this newsletter at http://www.naic.edu/about/newslett/aonews.html

ouris (see the Radio Astronomy High-lights). He admits to enjoying hiking,golf, cricket, music and learning lan-guages. We look forward greatly to himjoining us in 3 months time, and hopethat he will find the island to his taste —We can provide the hiking, golf, and mu-sic, Duncan, with Spanish there to belearned; I guess it’s not too far to Anti-gua, Trinidad and Jamaica for the crick-et either!

Karen O’Neil was also here at Arecibofor the first time recently, observing lowsurface brightness (LSB) galaxies withJim Schombert (again, see Radio Astron-omy Highlights). Karen pursued her un-dergraduate studies at Marlboro College,before moving to the University of Ore-gon where she completed her Ph.D. in1997 under Greg Bothun. Her thesis hadthe intriguing title of, “Faint Fuzzy Stuff:The Missing Baryons?” That faint fuzzystuff was LSB galaxies, and in her workshe focused on discovering and classi-fying these extremely faint objects, andinvestigating their composition and evo-lution. In particular, she used the Mc-Donald Observatory 0.8-m opticaltelescope with a 2048 x 2048 CCD cam-era to search the local universe for LSBgalaxies, cataloging over 120, mostlynew discoveries. Among these are thefirst very red LSB galaxies, the finalproof that LSB galaxies cover the entirerange of galaxy development. On herrecent trip to Arecibo, Karen made herpresence felt quickly as one of the firstpost-upgrade HI observers. She even leftus a very full and useful set of notes onobserving with the post-upgrade spec-tral-line system. When she returns inOctober, we trust that she will enjoy hertime here as much as we will enjoy hav-ing her as a colleague.

New Electronics EngineerAndrew Dowd has joined the electron-ics department of the Arecibo Observa-tory. Having worked previously atNRAO, the University of Arizona, andSAO he comes with vast experience

working with signal processing systems,and a very good understanding of our in-strumentation and requirements.

Andrew grew up near Cornell Uni-versity, where much of his family stillresides. He arrived in Puerto Rico withhis wife, Zoe. Their interests includeScuba Diving, Sailing and Hiking, all ofwhich they intent to pursue actively inPuerto Rico. They also enjoy snow ski-ing, which means they will need to re-turn state-side for occasional visits tocolder climes. We are very pleased tocount Andy as a member of our Staff.

New Telescope OperatorGerson Ortíz Ortíz joins the telescopeoperations group as Operations Techni-cian. He obtained a Bachelors degree inPhysics and Applied Electronics from theUniversity of Puerto Rico, Humacaocampus. He took their astronomy courseand worked as an assistant at their ob-servatory. In college he also did researchwork on Pentium processors. After grad-uation Gerson worked for one year atElizabeth Arden in the area of Manage-ment Information Systems. Gerson en-

Gerson Ortíz

Andrew Dowd

Victor Negrón

joys water sports and physical fitness ac-tivities. We are pleased to welcome Ger-son to the Observatory.

New Transmitter Technician

Victor Negrón Dávila, also with a Bach-elors degree in Physics and Applied Elec-tronics from the University of PuertoRico, Humacao campus has joined ourstaff as an S-band technician. At Hu-macao he participated in the NASAsponsored Solar Moon Buggy projectwhich won third place in last year's na-tional competition held in Huntsville, Al-abama. Victor practices Judo andOlympic Wrestling and was Judo cham-pion of the LAI (Inter-university Athlet-ic League of Puerto Rico) for the last fouryears and wrestling LAI champion lastyear. We welcome Victor to our staff.

Adiós Ray GonzálezAlthough Ray was less than three years“old” at the Observatory, he became agrandfather last year (congratulationsRay!). As a devoted head of the family,he and wife Deborah decided that muchas they liked Puerto Rico and the Obser-vatory, they preferred to live closer totheir children. So it was time to moveon. We are happy that Ray could takeup a software analyst position at NASAGoddard Space Flight Center with spe-cial responsibilities for the X-Ray orbit-ing telescope, only a short drive awayfrom his family. Visitors to the ControlRoom can see Ray's mark on the AOmonitor displays, the S2 (VLBI) recordersystem, and the ARTS user interface. Wewish Ray and family all the best.

TO:

NAIC/Arecibo Observatory Newsletter504 Space Science BuildingCornell UniversityIthaca, NY 14853-6801 U.S.A.

*address correction requested

NAIC/AO Newsletter is published three times per year by theNational Astronomy and Ionosphere Center.The NAIC is operated by Cornell University under a cooperativeagreement with the National Science Foundation.

Tapasi Ghosh, Jonathan Friedman & José F. Salgado, Editors

Address: NAIC/AO NewsletterP.O. Box 995Arecibo, PR 00613-0995

Phone: +1-787-878-2612Fax: +1-787-878-1861E-mail: [email protected] or [email protected]: www.naic.edu

july 1998, number 25newslet/no25/naicno.25.pdf · ural test targets for the radar system, are fig....

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