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

March 1999, Number 27

INDEX

Atmospheric Science Highlights .....1A Note to Arecibo Telescope Users .4Pulsar Observers Explore Turbulent

Milky Way ....................................4Radio Astronomy Highlights ..........6Receiver Test Facility .......................1 1Job Opportunity ..............................1 1Comings and Goings........................1 2

Atmospheric Science HighlightsCraig Tepley and Nestor Aponte

Several studies of the upper atmo-sphere took place at Arecibo since

the last NAIC Newsletter went to press.We begin with a more complete descrip-tion of the topside ionospheric experi-ment that occurred in late November oflast year, which we only briefly men-tioned in that report.

In November, we conducted thePlasmaspheric Observations of LightIons in the Topside Exosphere (PO-LITE) World Day campaign from the22nd through the 25th. One goal of PO-LITE is to advance our appreciation ofthe topside light ion morphology and

Beginning with the June 1, 1999 proposal deadline for Arecibo Observatory, we will have a WWW form for the proposalcover sheet. A preliminary version is available for browsing at: http://www.naic.edu/~ehowell/cover.html. Comment andsuggestions for improvements are welcome. The body of the proposal will still be submitted as a PostScript file, sent byelectronic mail, or hardcopy by regular mail. - Ellen Howell

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February 13, 1999February 14, 1999

AO AM He Data

Fig. 1: The top panel shows the metastable He 10830 Å NIR Doppler profile in the morning twilight at Arecibo

on February 13, 1999. The spectrum was obtained using a NIR Fabry-Perot Spectrometer with a total integra-

tion time of 2.5 minutes. The bottom panel shows upper thermospheric and exospheric temperatures derivedfrom the 10830 Å linewidths. The cross-hatched area envelopes the mean temperature to one standard devia-

tion. (Courtesy of Robert Kerr, Scientific Solutions, Inc.)

NAIC/AO NewsletterMarch 1999, Number 27 2

dynamics through a combination ofmodeling efforts and coordinated obser-vations made by the incoherent scatterradar chain and by DMSP (Defense Me-teorological Satellite Program) over-flights. The use of the full latitudinaland longitudinal extent of the radar chainwas critical to this campaign in that onekey objective was to study the latitudi-nal and longitudinal variations of hydro-gen, oxygen, and helium ions.Simultaneous measurements of neutraloxygen, hydrogen, and helium are alsoimportant to explore the coupling be-tween ion and neutral species in the low-er part of the topside ionosphere.

For this particular campaign, the ob-servations during, or near to the solstic-es were of special interest becausesignificant asymmetries in field-alignedion flows are at their maximum duringthese periods. In the winter, the heliumion layer descends in altitude and in-creases in strength, making the observa-tions easier for most other incoherentscatter radars. Because of its vast sensi-tivity, Arecibo, on the other hand, is wellpositioned to study the helium ion layerthroughout the entire year. We ran theradar for about 60 hours during the coreperiod of POLITE with optical measure-ments on the associated nights.

During POLITE, and for a similar ad-jacent study proposed by Robert Kerr etal. (Scientific Solutions, Inc.), Kerr andhis student Steve Oetting installed theirinfrared Fabry-Perot interferometer inthe Airglow Lab to observe the He10830-Å metastable emission that orig-inates in the thermosphere. Their instru-ment provided critical data on the finalpiece of the ion-neutral chemistry of thehigh-altitude ionosphere by furnishingrelevant information on neutral heliumto compare with He+ measured with theradar. We can also extract O+ and H+

concentrations from radar spectra — theneutral counterparts were determinedfrom optical measurements of the O8446-Å and Hα 6563-Å airglow using theObservatory’s photometers.

In addition, for these studies we re-configured one of our own Fabry-Perotinterferometers to be sensitive to Hα bychanging the etalon plate spacing andperforming a number of other instrumentchanges. High-spectral resolution stud-ies of Hα help us determine the flux ofpotentially “hot” hydrogen atoms thatmay have sufficient energy and velocityto escape the Earth’s atmosphere. Sev-eral additional nights of observationwere made throughout the rest of theyear to support these winter-time high-altitude studies, even during times whenradar observations were unavailable.The purpose of the extended optical runswas to gear-up for a major, early springtopside ionospheric campaign that is tak-ing place as this Newsletter goes to press.

In mid-January, Silvia Duhau (U. ofBuenos Aires) together with MichaelKelley (Cornell U.) and Mike Sulzer(NAIC) carried out several radar runs.The purpose of their experiment was toverify, or not, various rocket Langmuirprobe measurements showing elevatedelectron temperatures in the lower partof the E-region ionosphere during win-ter months around noon. The specificgoals of these incoherent scatter radarmeasurements were to:

1. make the most accurate possible E-region measurements of electrontemperature (T

e) and ion temperature

(Ti), preferably by more than one in-

dependent method, and

2. look for enhancements in the plas-ma line, possibly indicating a tail inthe electron distribution.

One set of temperature measurementswas obtained from coded long pulse ionline observations. Also, an independentmeasurement of T

e/T

i was obtained by

comparing the coded long pulse plasmaline electron density measurements withmeasurements derived from the ion linepower profile. Once the near field re-sponse of the radar was determined, veryhigh quality measurements of T

e/T

i be-

came possible down to 103 km.

In the first three days of the experi-ment we obtained simple power profiles,as well as ion and plasma, and coded longpulse ion line measurements in order todetermine the behavior of the E-region.The last two days used coded long pulseion and plasma line measurements, re-cording the raw data on exabyte tape. Itis these measurements that give extreme-ly high quality plasma line profiles, butthe analysis is very computationally in-tensive. About one fourth of the datahave been analyzed, covering one of thenoon periods. So far, no evidence of el-evated temperatures has been found.

Analysis of the data is continuing.Duhau is developing a collision modelfor the lower E-region so that accuratetemperature measurements can be ob-tained using the ion line spectra. Thegoal is to obtain two independent mea-surements of T

e/T

i over the entire E re-

gion.

The use of the high quality plasmaline profiles in combination with highresolution ion line measurements (madefrom the same radar pulses by recordingtwo channels at once) is a new technique.Preliminary results indicate that it is pos-sible to use the same data, which extendsup to about 190 km to measure the mo-lecular ion fraction with sufficient accu-racy to make comparison with modelsuseful. The difficulty with molecular ionfraction measurements is that the molec-ular and O+ masses are so close that it isnot possible to distinguish them and si-multaneously measure T

e/T

i because the

effects on the spectrum are very similar.With T

e/T

i otherwise determined, the dif-

ferent masses can be seen, although itrequires a lot of independent samples toobtain useful results.

A new focused World Day experi-ment was initiated this past February,called the Global Ionosphere-Thermo-sphere Coupling Study (a.k.a. GITCS).It was a three-day study proposed byMike Kosch (Max Planck Institut fürAeronomie) and Chantal Lathuillere(Centre National de la Recherche Scien-tifique - CNRS). The objectives of this

NAIC/AO NewsletterMarch 1999, Number 27 3

multi-radar, multi- optical experimentwere twofold. First, simultaneous radarand optical measurements of key iono-spheric and thermospheric parameters,such as, electron concentration, ion andelectron temperatures, and ion velocitiesobserved parallel to the Earth’s magnet-ic field, will be used to constrain globalmodels of the thermosphere. Two keymodels used in this study are the Uni-versity College of London 3D Thermo-spheric model and the GrenobleTRANSCAR model. A second objec-tive of GITCS is to determine ion-neu-tral collision frequencies in the F-regionionosphere between O and O+ using me-ridional neutral winds either measureddirectly via optical interferometry, or in-

ferred from incoherent scatter radar mea-surements of ion drifts. The atomic ox-ygen concentration and neutraltemperature needed to determine O-O+

collision frequencies will be taken frommodels of the neutral atmosphere or fromdirect measurement where available.

During the month of February, theArecibo 430 MHz radar ran for nine con-secutive nights (Feb. 12-20). This waspart of a combined effort by Kelley andErhan Kudeki (U. of Illinois) to investi-gate the effects of geomagnetic stormsand substorms in the ionosphere overArecibo, as well as E-region layer for-mation, dynamics and plasma instabili-ties. The Arecibo radar measurementswere complemented by several other in-

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struments, includ-ing two coherentradars from Cor-nell (CUPRI, runby Wes Swartz)and Illinois (Kude-ki), two imagersfrom Cornell(Francisco García)and Los Alamos(Tom Armstrong),and the Arecibosodium resonancelidar and photom-eters. Severalnights were quiteactive in the E-re-gion. In particular,the night of Febru-ary 20-21 had aspectacular eventnear 100 km alti-tude which wasobserved almostcoincidentally byall three radars andthe lidar (see Fig.2). At nearly thesame time a verydisturbed F-layerdrifted overheadwith structurequite similar to anevent observed inJune 1998. More-

over, we were treated to a geomagneticstorm during February 18-19. This stormprevented the usual midnight collapseduring the night of the 18th and alsoraised the height of the F-peak by about100 km. This storm resulted in spectac-ular airglow images showing plasma de-pletions surging pole-ward at highvelocity. The success of the project wasmuch aided by the willingness of astron-omer Carl Heiles (UC Berkeley) to tradetime on the telescope on an active nightfor time later in the week.

As mentioned above, we supportedKudeki et al.’s study with optical obser-vations of the lower thermosphere andupper mesosphere. Craig Tepley (NAIC)and Eva Robles (NAIC) carried out Fab-

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Arecibo Sodium Density Data from 20-21 February, 1999

22

Fig. 2: A “sporadic event” as seen from the (a) 430 MHz incoherent scatter radar power profile, (b) the Na resonance density lidar and(c) CUPRI, occurred at around midnight local time on the night of February 20-21, 1999. Unusually long-lived sporadic E and Na

enhancement layers were observed near 101 km altitude on this night. Plasma frequencies exceeded 3 MHz and the Na densities were

above 10,000 per cc in the layers. At the same time, line-of-sight Doppler velocities measured by CUPRI exceeded 250 m/s. The 2-secaverage spectra are from February 20, 1999 at 23:43:34 AST. The y-axis is range (actual height is near 100 km), and the x-axis is

Doppler velocity. On the right hand side of the spectral plots is the power profile. (2a courtesy of Nestor Aponte, 2b courtesy of Jonathan

Friedman, 2c courtesy of Wes Swartz)

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NAIC/AO NewsletterMarch 1999, Number 27 4

Pulsar Observers Explore TurbulentMilky WayDan Stinebring (Oberlin College)

We know that the interstellar medi-um is inhomogeneous on a tre-

mendously wide range of size scales: allthe way from the size of spiral arms downto microturbulence as small as 106 cm.Pulsar scintillation observations are thebest technique available for probing theionized ISM in the size scale range from108 cm to 1014 cm. In January 1999 agroup of us from Cornell University andOberlin College converged on AreciboObservatory for a two-week session ofpulsar scintillation observations. Ob-serving for about 70 hours at both 430and 1400 MHz, we investigated scintil-lation from a group of about 15 strongpulsars. These were pilot observations todemonstrate that we could obtain usefulscintillation data with unprecedented fre-quency and time resolution. The obser-vations were highly successful. Not onlydid the telescope and the spectrometerwork with very few problems, but thepulsars and the ISM cooperated, too. Wehave seen some features in the new datathat are unlike any that we have seen

A Note to Arecibo Telescope UsersDuring 1998 there were three proposal deadlines for which 128 proposals were received. The total telescope time requestedwas approximately 11,500 hours; clearly we are very heavily oversubscribed at present. This is particularly so as currentlywe still need to dedicate a significant fraction of available telescope time for instrumental tests and calibration, and softwaredevelopment.

As a consequence of the above, it is likely that many highly graded proposals will not be scheduled within the eight-month window during which they are active, and following which non-scheduled proposals automatically cease to be valid,as per established procedures. Nevertheless, if you wish your unscheduled proposal to remain active after the eight months,the recommended strategy is to re-submit it twelve months after the deadline for which it was originally received, thuskeeping it in the queue. Note that on resubmission it will receive a new proposal number, while the old version will beretired. Our current proposal cover sheet contains an entry for declaring that this is a re-submission with no changes, inwhich case the proposal will not be sent to the referees. Of course, if you have made changes either in response to refereecomments, or for other reasons, you should indicate this at the appropriate place on the cover sheet and the modifiedproposal will be sent for refereeing.

We have placed our schedule on the web to provide you with a better feel of the current situation. Our goal is to schedulefour-month blocks as much in advance as possible, but this is still difficult at present. Please note that unless you havespecified on the cover sheet certain scheduling constraints we assume that you will be available to come to Arecibo whenscheduled.

- Daniel Altschuler

ry-Perot measurements of neutral windsand photometric observations of variousupper mesospheric airglow emissions,such as, O(1S), OH, and O

2. The neutral

temperature at different heights in the at-mosphere are extracted from these air-glow data. Ann Chojnacki (Cornell U.)and Jonathan Friedman (NAIC) also op-erated our resonance fluorescence lidaron many of the nights of the experimentmeasuring the structure of the mesopauseregion between approximately 80 and105 km altitude using the sodium layeras a tracer. An interesting example ofthe detailed dynamics present at this al-titude range is shown in Fig. 2b, alsofrom the night of Feb. 20-21, where wesee the influence of pronounced atmo-spheric gravity waves that strongly re-veal their presence in the Na layer. Theenhanced Na layer near 101 km was veryunusual in that it was long lived. Theselayers normally last on the order of anhour, while on this particular night it wasapparent throughout the 7+ hour obser-vation period.

A four-day World Day, Lower Ther-mosphere Coupling Study (LTCS) oc-curred in early March. This particularexperiment was somewhat of a merger

between two different scientific focuses— the “standard” tidal study character-istic of LTCS observations in the past,with the influence of magnetic stormson ionospheric conditions. Generally,the effects of magnetic storms on the ion-osphere are more pronounced at higheraltitudes and are believed to have verylittle influence deep within the atmo-sphere.

With the hope of catching an intensegeomagnetic disturbance by flexiblyscheduling a “floating” observation win-dow for this experiment, the March 1999LTCS attempted to quantify whether ornot there is a major, or even minor, stormeffect on the lower thermosphere. Un-fortunately, initial results are somewhatinconclusive because only a smallamount of magnetic activity was ob-served during the experiment. This studywas a pilot project for the upcomingCEDAR-TIMED investigations that be-gin next year after the launch of theNASA TIMED satellite that will studythe upper mesosphere and lower thermo-sphere.

NAIC/AO NewsletterMarch 1999, Number 27 5

before and have given us the incentivefor a deeper analysis of scintillation be-havior.

The Cornell part of our group con-sisted of Jim Cordes and graduate stu-dent Maura McLaughlin. The Oberlincontingent was made up of four under-graduates (Kate Becker, Joaquín Espino-za Goodman, Mark Kramer, and JimSheckard) and Dan Stinebring. The fourundergraduates were able to join the ob-serving trip because of generous supportfrom the National Science Foundation(NSF). We posed a bit of a shock to thecomputer group at first, descending insuch numbers before their new comput-ers had arrived, but within a few dayswe were well set with workstations andhad distributed our observing and pro-cessing tasks around the group. Al-though this was a first visit to Arecibofor the Oberlin students, McLaughlinwas an invaluable guide in all facets ofthe observations. She quickly helpedorient both the other students and my-self in the intricacies of obtaining andhandling the large quantities of data in-

herent in these observations (~5 MB/sdata rates). Soon we were in a produc-tive routine of observing followed byrapid-turnaround analysis of the data thatallowed us to adjust our observing sched-ule for the following night.

The success of our observations de-pended critically on a new spectrometerthat is coming into routine operation: theAOFTM, which faithful readers of thesepages will know is the Arecibo Obser-vatory Fourier Transform Machine. Thisspectrometer can take a 10-MHz widebandpass and split it into 1024 frequen-cy channels. What sets it apart from oth-er spectrometers is that it producesspectral estimates every 0.1 ms, allow-ing for the accumulation of spectra atdifferent phase windows of a pulsarpulse. This can be accomplished evenfor millisecond pulsars, a few of whichwe included in our observing list. Fortu-nately, McLaughlin and Cordes, alongwith Zaven Arzoumanian of Cornell de-veloped most of the software for theAOFTM and were able to make small

modifications to facilitate our data-tak-ing.

Our data analysis consisted of pro-ducing dynamic spectra from the muchlarger quantity of raw data we obtainedin each pulsar observation. A dynamicspectrum is a two-dimensional array,each row of which is the spectrum of thepulsar (for a particular phase window)for an integration time that we set to be10 seconds. Over the course of a 1-2hour long observation, these spectrabuild up to show the dynamic behaviorof the pulsar spectrum (see Fig. 3). Thetime variation of the spectrum is causedby the relative motion of the pulsar, theISM, and the observatory during the ob-servations. Since pulsars are high-ve-locity objects (space velocities in therange of 200-400 km/s and beyond), thepulsar motion dominates.

We had several scientific goals forthese observations. One was to look foroccurrences of strong refraction in theionized ISM. We wanted to scan a groupof promising pulsars looking for occa-sions when the signal from the pulsar gotsplit into a small number of discrete raypaths by refracting structures in the ISM.Such occasions show up as interferencepatterns in the dynamic spectrum, whichcan then be analyzed further to extractinformation about the bending angle ofthe rays, the number of discrete ray bun-dles, and the amount of flux density ineach bundle. Such studies have beenpursued in the past, but we believe thatthe post-upgrade Arecibo telescope canmake substantial new contributions tothis field, both because of the improvedtelescope performance, the increased fre-quency agility, and the AOFTM and fu-ture instrumentation. Arecibo’s uniquesensitivity is vital to these observations,as is the high frequency resolution of theAOFTM, since the interference patternswe are looking for are often faint, andthe most interesting of them occur asrapidly oscillating patterns across the dy-namic spectra.

Such incidents of strong refractionare interesting not only for what they tell

PSR B1933+16

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Fig. 3: The dynamic spectrum of the interstellar scintillations of pulsar, PSR B1933+16, at a frequency of

1406 MHz. The observations represent a one-hour track on the source.

NAIC/AO NewsletterMarch 1999, Number 27 6

Radio Astronomy HighlightsKiriaki Xilouris and Chris Salter

HI in the Milky Way and ExternalGalaxies

Herbig-Haro (HH) objects are shockfronts formed by the interaction of

high-velocity flows of gas ejected bynewly born stars and the ambient medi-um. Outflows from young stars, whichhave been observed with velocities of upto 500 kms-1, play a major role in the dis-persion of ambient gas around youngembedded stars. In addition, the com-bined kinetic energy input of many out-flows into the surrounding gas may alterthe properties of the parent cloud by thegeneration of turbulent motions. Recent-ly, it has been found that not only do par-sec-scale HH flows exist, but that theyare also quite common. This has sparkedmajor interest on the impact of these en-ergetic mass flows on their environment.Giant HH flows are either comparablein length or longer than associated COoutflows, and have sizes about an orderof magnitude larger than the cloud coresfrom which they originate. Many HHobjects are found in regions where thereis little or no CO emission and lie welloutside the boundary of the parent darkcloud against a rich background of starsand galaxies. Thus it is evident that theyhave blown out of their parent molecu-lar cores and clouds and into the low-density intercloud medium (ICM). Onceout of the cloud, the flows inject massand energy directly into the surroundingICM. Mass outflows from young starscan heat, ionize, dissociate, and entrainmaterial in the ICM. One or more shocksassociated with the same flow can accel-erate the entrained ICM gas to velocitiesgreater than those of the quiescent cloud.It has also been proposed that the cumu-lative action of many outflows andshocks may be the primary agent in theproduction of turbulence in molecularclouds and the surrounding ICM.

intensity. In the spectrum shown here itis not possible to clearly delineate be-tween scintillation maxima and minima.The scintillation structure has taken ona more complicated structure. We arenot yet sure why this is so, although weconjecture that we are seeing the inter-ference between 5-10 discrete ray bun-dles. We have further work to do to seeif this idea holds up. However, we wantto further analyze this dynamic spectrumto extract more information about theinterfering rays and hence the structuresin the ISM that are producing the pat-tern. The detection and analysis of fine-scale complicated features such as thoseshown here would not be possible with-out Arecibo’s sensitivity and the frequen-cy resolution provided by the AOFTM.

Another intriguing pattern in someof the dynamic spectra is the presenceof very low-level interference patternsthat have roughly the same orientationangle but a wide range of ridge line sep-arations, similar to flying perpendicularto the prevailing ridge line of an oldermountain range like the Appalachians.What is remarkable in the patterns thatwe are seeing is how narrow and regularare their spectral signatures, seen mostclearly by forming the 2-d power spec-trum of the dynamic spectrum. Thewisp-like features we see must resultfrom the interference between a well-defined ray bundle and some more ex-tended feature of the image. Theextended feature has to be somewhatone-dimensional in character to explainthe results, however. Again, we needfurther analysis and modeling to fullyunderstand what these high quality dataare telling us.

We returned from our observing runwith new questions uncovered ratherthan old questions answered. We find itis taking some time to get used to thehigh resolution and high dynamic rangeof these new spectra. They are differentenough from previous results that wewill be forced to improve the sophisti-cation of our modeling. Although thesedata did not easily fall into familiar cat-egories, the uncovering of new phenom-

us about the ISM but also for how wecan use them to learn about the pulsarmagnetosphere. Pioneering work byCordes and Alex Wolszczan (Penn StateU.) at Arecibo in the 1980’s demonstrat-ed that episodes of refractive fringing al-low nearly nanoarcsecond angularresolution indirect views of the pulsaremitting region. By comparing the dy-namic spectrum produced at one portionof the pulse profile with that at anotherwe can set limits on, or even detect, thetransverse separation of the emitting re-gions giving rise to different portions ofthe pulse profile.

Finally, one of us (Cordes) has de-veloped a technique whereby scintilla-tion observations and VLBI propermotion measurements of a pulsar can becombined to obtain an improved distancedetermination. This is particularly impor-tant for pulsars at high galactic latitudewhere the Taylor and Cordes electrondistribution model fails to specify thedistance because the pulsar is above thebulk of the galactic plane electrons thatcontribute to the dispersion measure.High quality dynamic spectra obtainedat several epochs are necessary input tothis technique.

Since returning to our home institu-tions, we have been busy analyzing thedata obtained in January. We plan onmaking at least one presentation on thesedata at the upcoming AAS meeting inChicago, but we can mention some pre-liminary highlights of the data set here.First of all, despite persistent interfer-ence, particularly at 430 MHz, the datawere of consistently high quality. TheAOFTM appears able to handle high lev-els of RFI and keep it relatively isolatedfrom other frequency channels. In ourfirst pass through the data we ran acrossseveral dynamic spectra that are unlikeany we have observed before or are fa-miliar with in the literature. For exam-ple, the dynamic spectrum of PSR1933+16 shown in Fig. 3 has a compli-cated mottled appearance that is unlikethe standard dynamic spectrum, whichis generally more like a large body ofwater interrupted by islands of brighter

ena is part of the excitement that keepsbringing us back to “El Radar”.

NAIC/AO NewsletterMarch 1999, Number 27 7

In Jan 1999, Héctor Arce & AlyssaGoodman (CfA) searched for high-ve-locity neutral hydrogen (HI) entrained byshocks produced by giant HH flows inthe low-density ICM. Their targets wereHH objects lying well outside the darkcloud inhabited by the outflow source,previously discovered in the optical.They are certain that there is acceleratedgas at these positions, the tricky part isto detect it. All of the positions theylooked at suffer from Galactic HI “con-tamination”, and thus it is very probablethat any observed high-velocity emissioncontains both background (Galactic)emission and the high-velocity entrainedgas it is desired to detect. To cope withthis problem, these observers took anumber of OFF positions (different foreach source) situated less than 10' aroundthe ON-source position. The spectra ofthe OFFs (together adding up to have thesame integration time as the ON posi-tion) were averaged and then subtractedfrom the ON position in an attempt tosubtract the Galactic emission from theON spectra. To beat down the noise, in-tegrations of many hours were taken oneach position. Ultimately they hope todetect very low-emission high-velocitywings in the (ON - OFF) spectra, indic-ative of high-velocity gas accelerated by

HH flow-produced shocks. Detection ofthe high-velocity wing will enable cal-culation of the amount of energy thesegiant HH flows deposit in the ICM, andhow much they contribute to ICM tur-bulence. The results obtained from theseobservations, in conjunction with pub-lished optical/IR spectral and photomet-ric observations of the same HH objects,will aid understanding of the effectswhich mass outflows from young starshave on the low-density ICM and theprocess of gas entrainment by shocks.In addition, this combination of obser-vations will advance our knowledge ofthe physical characteristics of the ICM.

Karen O’Neil (NAIC), Greg Bothun,& Jim Schombert (Oregon) undertook aHI survey of over 100 low surface bright-ness (LSB) galaxies between Jun andNov, 1998. This resulted in 41 detectedgalaxies with 22.0 mag arcsec-2 < µ(0)

B

< 25.0 mag arcsec-2. The detectionsrange in color from very blue throughthe first λ21-cm detection of very redLSB galaxies, while their HI mass-to-luminosity ratios vary from reasonablygas poor (M

HI/L

B = 0.1 M

o/L

o) to possi-

bly the most gas rich galaxies ever de-tected (M

HI/L

B = 46 M

o/L

o). Analysis of

the structural properties of these galax-

ies shows a diverse population, rangingfrom dwarfs to intrinsically luminoussystems, though no large, Malin I-typegalaxies were identified. They found nocorrelation between the galaxies’ colorand M

HI/L

B, and in fact found red LSB

galaxies with MHI

/LB> 9 M

o/L

o. How-

ever, contradicting the idea that star for-mation in these galaxies has beendelayed only in those regions with an un-derdensity of HI gas, is their discoverythat the highest M

HI/L

B values corre-

spond to galaxies with scale lengths lessthan 2 kpc. Additionally, they havefound no correlation between velocitywidths and central surface brightness orM

HI/L

B for these galaxies, showing a lack

of support, but by no means discredit-ing, galaxy formation theories which relyon a µ(0) dependence on angular mo-mentum. Finally, the most significantdiscovery of this survey is a completelack of correlation between the rotation-al widths of the galaxies and their abso-lute magnitudes. Attempts to fit thegalaxies to even the broadened HI Tul-ly-Fisher relation of Zwaan et al. (MN-RAS, 273, L35, 1995) failed (see Fig.4). It thus appears likely that the observedHI Tully-Fisher relation, like the Free-man (ApJ, 160, 811, 1970) law concern-ing galaxy surface brightnesses, ismerely a selection effect, showing not alaw of galaxy formation but merely ourlimited ability to view the Universe.

Molecular-Line StudiesWendy Lane & Frank Briggs (Kapteyn)searched for redshifted 1665- and 1667-MHz OH absorption in two low-redshiftλ21-cm absorbers along the line of sightto the QSO B0738+313. With the newcorrelator, both transitions could be ob-served simultaneously for both redshiftsystems by setting four separate 3.125-MHz wide subcorrelators at frequenciesnear 1360 and 1540 MHz in the band ofthe L-wide receiver. No absorption wasseen to a 3σ limit of 0.12% in either sys-tem. During the observations, 10 minwas also spent observing the λ21-cm ab-sorption in the lower redshift system(Fig. 5). This observation resolved both

B(m

ag)

-15.4

-16.8

-18.2

-19.6

-21

20 50 100 200 50014

W50 (km/s)

Fig. 4: The 50% velocity widths versus absolute B magnitude for all galaxies detected by the survey of O’Neil,Bothun, & Schombert. The solid and dashed lines are the 1σ and 2σ fits to the Tully-Fisher relation for

previously detected low surface brightness galaxies by Zwaan, et al. (1995). (Courtesy Karen O’Neil)

NAIC/AO NewsletterMarch 1999, Number 27 8

the main line and the second, weakercomponent for the first time. The ex-treme narrowness of the absorption pro-files constrains the kinetic temperatureof the absorbing gas to be less than 350K. The HI column density in the λ21-cm lines calculated with the kinetic tem-perature is only half of that measured inthe Damped Lyα line for this sys-tem. It seems likely that the “miss-ing” gas might lie in a warmerphase component not detected bythese observations.

Jeremy Darling & RiccardoGiovanelli (Cornell) have discov-ered the galaxy IRAS 06487+2208to be an OH Megamaser by ob-servations of the 1665- and 1667-MHz OH lines redshifted to about1457 MHz (cz = 43080 kms-1).IRAS fluxes for the object give aninfrared luminosity of L

IR ~ 1012.5

h75

-2 Lo, placing it in the class of

ultraluminous infrared galaxies(L

IR > 1012 L

o), and making it a

good megamaser candidate. IRAS06487+2208 is unresolved in theDigitized Sky Survey, so these ob-servers cannot say if the object isan interacting system. The 1667-MHz line is the stronger of the twoOH lines (S

1667/S

1665 ~ 6), with an

isotropic luminosity of 102.8 h75

-2 Lo. This

line exhibits a full width at half-maxi-mum of 241 kms-1. There are clearly anumber of different sources spread overa range of velocities which contribute tothe 1667-MHz line, including an OH ab-sorber. As a test of the validity of thedetection, the 1665-MHz line was plot-ted at the same velocity as that at 1667MHz (Fig. 6) such that the two lines, ifgenuine, would show some correspon-dence of features. The two lines do in-deed show some similar characteristics,most notably an absorption feature nearthe center of both. IRAS 06487+2208was selected to be a strong FIR source,but radio-quiet (from NVSS, S

1.4 GHz =

10.8 mJy) to minimize standing wavesin the bandpass.

In the Arecibo sky there are 355IRAS sources with an LRS 2n spectraltype, which are expected to have detect-able OH masers. Only 52% do. Thisposes the question of just why there areso many objects without masers. Dur-ing the past months, Lewis (NAIC) hasmade OH observations of the last 40,rather blue, objects in the sample, whichhe has also searched for 22-GHz water

masers. The percentage exhibiting ma-sers is surprisingly independent of theirIR colors. It now seems likely that the2n sources without masers are predomi-nantly objects that have passed througha recent thermal pulse, and so are at aphase where the new energy from Heburning is enhancing their luminosities,thus lengthening their periods, and so in-creasing their mass-loss rates. Such starsexperience a sudden coupling betweentheir gaseous shells and radiatively driv-en dust, when the gas density becomessufficient to slow down dust particles.This in turn results in an abrupt increasein the expansion velocity of the circum-stellar gas, which causes it to move be-yond the prior equilibrium distributionof screening dust; in effect the objectswithout masers are those without a suf-ficient dust screen to protect their mole-cules. This scenario suggests that theseobjects should also have systematicallylonger pulsation periods, which they do.

Lewis has also begun a project toimprove the quality of existing data onthe Arecibo set of OH/IR stars. The firstsegment of this project was to confirmthe nature of objects with |b| > 10o andred IR colors, most of which are associ-ated with young stellar objects wherethese overlap the IR color range of thereddest OH/IR stars. Three of the 1612-MHz detections, 03220+3035,04236+2559 & 04305+2414 have soli-tary 1665-, 1667- and 1612-MHz fea-tures at just the same velocity, and soare probably YSO. However, as a resultof this work, Lewis has found a new pro-to-planetary nebula with OH emission,19386+0155, an object very like the pro-totypical example, 18095+2704, foundat Arecibo 10 yr ago. The accompany-ing spectra (Fig. 7) were observed simul-taneously, and result from 15 minON-source integration.

Rachel Kleban (Cornell) & PaulGoldsmith (NAIC/Cornell) continuetheir series of OH-absorption measure-ments in the 1612-, 1665-, and 1667-MHz lines of OH, against sevenradio-continuum background sources. A

Flux

Den

sity

(mJy

)

0

2

4

6

8

10

41000 42000 43000 44000 45000 46000

cz (km/s)

IRAS 06487+2208: OH Megamaser at cz=43080 km/s

νo = 1665.4018 MHz

νo = 1667.359 MHz

Fig. 6: The OH spectrum of ultraluminous infrared galaxy,

IRAS 06487+2208, which is redshifted to cz = 43080 kms-1.

the upper trace shows the spectrum shifted such that the1665-MHz line coincides with that from the 1667-MHz tran-

sition in the lower trace. The spectrum spans 25 MHz. The

upper trace is offset arbitrarily in flux density to ease view-ing of the correspondence of peaks and the absorption fea-

ture present in the two lines. (Courtesy Jeremy Darling)

Nor

mal

ized

Int

ensi

ty

Velocity (km/sec)-50 0 50

1

0.95

0.9

0.85

0.8

Fig. 5: A 10-minutes ON, 10-minutes OFF observa-

tion of the l21-cm line at z=0.0912 towards the QSOB0738+313. Channel spacing is 0.7 kms-1, allowing

this extremely narrow line to be resolved for the first

time. (Courtesy Wendy Lane)

NAIC/AO NewsletterMarch 1999, Number 27 9

sample absorption spectrum is shown inFig. 8. The sources are located neardense cores in the Taurus molecularcloud, the observers having previouslymade small emission maps at these sitesin CO,13CO, and C18O. These observa-tions are the second of an on-going set,and the sources will be reobserved sev-

eral more times in OH and H2CO, be-

ginning in March 1999. The aim is tolook at how the spectra change with timeas the parallax from the earth’s orbit anddifferential galactic rotation change therelative positions of the clouds and ra-dio sources. The data will be combinedwith a radiative transfer model to inves-tigate the small-scale structure of molec-ular clouds at a variety of scales.

PulsarsMost encouragingly, during the past fewmonths Arecibo has welcomed to theObservatory several enthusiastic new-comers to pulsar research. These youngscientists have made their presence feltand left their mark here. Five Of these,Andrea Somer (Berkeley), Eric Splaver& Walter Brisken (Princeton), AdamChandler (Caltech) & Maceij Konacki(Penn State), are graduate students cur-rently working on Ph.D. projects basedlargely on data acquired with the upgrad-ed telescope. They have enlivened theObservatory with their presence and ex-cited the local staff with their new ideasand projects. Already experts in theirfield, and close to thesis completion, areFrederick Jenet (Caltech) & MauraMcLaughlin (Cornell) who have per-

formed impressive researchusing instruments that theyhave assisted in developing,and software which in largepart they themselves wrote.We wish all these young peo-ple well with their studiesand look forward to theircontinued participation at theObservatory.

An additional influx oflively young people camewith a group of undergradu-ates from Oberlin Collegeunder the guidance of DanStinebring (see previous ar-ticle). They visited the Ob-servatory for four weeks,getting involved with pulsarobserving and experiencingthe culture of radio astrono-

my first hand. Bernie Kuan & Claire Pet-tersen (Carleton) were also here gettingstarted in radio astronomy by studyingkinematic distances to pulsars withmulti-epoch HI-absorption observationsof pulsars with Joel Weisberg (Carleton)and Kiriaki Xilouris (NAIC).

Remote pulsar observing has nowbecome a regular practice at Arecibo,starting with the Arecibo-Berkeley Pul-sar Processor (ABPP) and continuingwith the Penn State Pulsar Machine(PSPM) and the Caltech Baseband Re-corder (CBR). Although still in its in-fancy, the appearance of remoteobserving demonstrates how easy it isto observe with Arecibo from the com-fort of one’s own office. Hopefully, withthe imminent appearance of a faster in-ternet connection and a sophisticateduser interface, remote observing will be-come a routine part of pulsar observingat Arecibo. We point interested users toour web site, (http://www.naic.edu/~pul-sar/observing.html), where the operationof each machine is described, as are theways to observe pulsars with the upgrad-ed telescope.

Fruchter (STScI), Xilouris, Lorimer& Eder (NAIC) and Angel Vázquez(NAIC) have been observing a newly dis-covered 25-ms pulsar from the STScI/NAIC drift-scan upgrade search to es-tablish its timing properties. The lackof any supernova remnant in its vicinity,together with its height above the galac-tic plane (1 kpc), suggest that this is nota young object. Indeed, it seems to fallin the rare class of recycled millisecondpulsars with periods between 10 and 40ms. At present, there are only 4 knownclass members, suggesting a very inter-esting evolutionary history. Two slowerpulsars, PSR J1905+06 and J0329+16,with periods of 989.6 and 893.4 ms re-spectively, have been confirmed from alist of 8 candidates resulting from theSTScI/NAIC drift-scan search.

Lorimer has used the Cornell Theo-ry Center (CTC) to analyze a large vol-ume of pulsar search data taken with thePSPM. These 430-MHz pointed obser-

1665 MHz OH Absorption Against a Radio Continuum Source

Flux

Den

sity

(m

Jy) 0

-50

Velocity (km/sec)0 1 2 3 4 5 6 7 8 9 10 11 12

Fig. 8: The 1665-MHz, OH-absorption spectrum against a

background radio continuum source seen through a dense re-gion of the Taurus molecular cloud complex. The spectrum is

the average of both polarizations, with 40-min total integra-

tion, and a resolution of 0.035 kms-1. Position switching in ahexagonal pattern around the central continuum source was

used. (Courtesy Rachel Kleban)

0

40

80

-20 0 20 40 60

1667 MHz

LSR Velocity (km/s)

0

40

80

1665 MHz

FL

UX

(m

Jy)

0

20

40

601612 MHz

IRAS 19386+0155

Fig 7: Spectra of the 1612-, 1665- and 1667-MHzOH lines from IRAS 19386+0155. The data were

taken on 11 October 1998, with a resolution of 0.14

kms-1. (Courtesy Murray Lewis)

NAIC/AO NewsletterMarch 1999, Number 27 10

vations were made around the positionsof optically identified white-dwarf starsin Oct 1998. The results of this searchwill help in establishing the frequencyof millisecond pulsars and white dwarfstars possessing a hydrogen-dominatedsurface.

Extensive searching at 430 and 1410MHz by Xilouris, Lorimer and collabo-rators has not revealed periodic radio sig-nals related to the magnetar, SGR1907+14. Neither folding modulo theX-ray period of the magnetar, nor search-ing for individual bright pulses, haveidentified periodic features. Followingthe recent claim of radio-pulse detectionfrom this source at low radio frequen-cies by Shitov (IAUC No. 7110), testobservations were also made at 47 MHz.The band around 47 MHz is heavily in-terfered by ground communication sig-nals making data reduction very difficult.

The facility pulsar spectrometer, theArecibo Observatory Fourier TransformMachine (AOFTM), is working very de-pendably and data-taking software isrunning smoothly. The acquisition of a108-Gbyte disk array allows the data tobe written directly to disk, facilitatingremote observing and freeing the observ-er from the constraints of tape-drivespeed.

Jim Cordes (Cornell), McLaughlinand collaborators have been using the160-node SP2 super-computer of the CTCfor most of theirAOFTM data process-ing. The CTC has re-cently acquiredMammoth and DLTtapes drives, makingthe porting of data fromArecibo much simpler.Using the AOFTM, thisgroup has confirmedseveral new pulsarsfrom pre-upgrade drift-scan and piggy-backsearches, and manymore await confirma-tion. One of these pul-

sars has a very large

apparent p, and futuretiming observationswill better constrain itsparameters. The samegroup has obtainedseveral pointings to-wards the LMXB,0614+091. Currentlythe data are being pro-cessed in shortchunks, with acceler-ation searches increas-ing the sensitivity toshort-period binaries.They have also ob-tained 20 half-hourpointings towards thenearby galaxy, M33,and are searching forisolated dispersedpulses in the hopes ofdetecting or constrain-ing the number ofCrab-like pulsars in that system. Fur-ther, as a result of an L-band search forpulsars in the Sagittarius spiral arm, thisgroup reports several interesting candi-dates which await confirmation. The datareduction is on-going.

In Jan 1999, a team from Cornell(Cordes & McLaughlin) and OberlinCollege (Stinebring, Kate Becker,Joaquín Espinoza Goodman, MarkKramer & Jim Sheckard) conducted a

PSR J1709+2313, 430 MHz, PSPM1

Pulse Phase Bin

Nor

mal

ized

Flu

x

0 100 200

two-week session of pulsar scintillationobservations. Such observations are thebest available technique for probing theionized ISM on size scales between 108

cm and 1014 cm. Observing for about 70hr at both 430 and 1400 MHz, they in-vestigated scintillation from a group ofabout 15 strong pulsars. Details of theseobservations can be found in the accom-panying article on page 4 by Dan Stine-bring.

Since Nov 1997, several millisecondpulsars have been timed with the PSPMby Anderson (Caltech), Konacki,Wolszczan (PSU) & Xilouris. ThePSPM’s performance has been moni-tored by timing the fastest known milli-second pulsar, PSR B1937+21, at 1400MHz. A long-term rms residual of 0.3µs achieved for this pulsar (Fig. 9) servesas an illustration of the PSPM’s currenttiming capabilities. As the result of con-tinuing timing observations of a 4.6-mspulsar, PSR J1709+2313 (Fig. 10), de-tected by the PSU/NRL group shortly be-fore the Arecibo upgrade, Anderson,Konacki & Wolszczan have obtained atiming model which successfully phase-connects the pre- and post-upgrade pulse

Fig. 10: The pulse profile of PSR J1709+2313 at 430 MHz made with the

PSPM.

PSR B1937+21, 1420 MHz, PSPM1

Nor

mal

ized

Flu

xT

OA

res

idua

ls [

µs]

PSR B1937+21, σ = 0.3 µs

Time [year]

0 50 100

1998 1998.5 1999-2

-1

0

1

2

Pulse Phase Bin

Fig. 9: PSPM observations made at 1420 MHz of the millisecond pulsar, PSR

B1937+21; a) the pulse profile, and b) the timing residuals.

NAIC/AO NewsletterMarch 1999, Number 27 11

arrival-time measurements for this ob-ject. PSR J1709+2313 is a 22.7-day bi-nary pulsar with very low eccentricity,small spindown rate, and low propermotion, all characteristic of low-massbinary millisecond pulsars.

The 14 known globular-cluster pul-sars visible from Arecibo have been reg-ularly timed by Sri Kulkarni (Caltech)and collaborators. These long-term ob-servations are being made remotely, andwill eventually lead to a determinationof the mass in the two relativistic binarysystems within these clusters. Further-more, the positions of the pulsars in theclusters, very precisely determined bytiming, will allow studies of the clusterinternal structure.

With a new data-taking system andsoftware, a Caltech group led by Fred-erick Jenet is trying to get a fresh look athigh time-resolution observations of bothfast and slow pulsars, giving new insightsinto the emission mechanism. It is hopedthat with this fresh approach they willcontribute towards unlocking the secretsof the pulsar magnetosphere.

The Coordinated Pulsar Timing ex-periment is an organized effort from fourgroups to obtain biweekly observationsaimed at simultaneously timing as manyas 12 millisecond pulsars using five dif-ferent backends. Already it has made its14th successful timing run. The groupshope to achieve submicrosecond timinguncertainties, giving the most accuratepulsar timing to date as the total extentof the observations increases. For themost recent run, the first “Observers of

the Month”, Eric Splaver (Princeton) andMichael Kramer (Berkeley) were presentat Arecibo to help with the run.

Somer, Backer (Berkeley) and col-laborators report that they have phase-connected observations of PSRJ0030+04 which indicate that this new-ly discovered source is a very nearby,isolated, 4.8 ms pulsar.

Tim Hankins (NMIMT) and collab-orators have made simultaneous, multi-frequency observations of single pulsesbetween Arecibo and the VLA. Hankinstook the VLA data, with local staff re-sponsible for the Arecibo observations.

VLBIArecibo participated in a 5-GHz VSOPobservation of the quasar J0149+05 on16 Nov 98. Sadly, the data handling unitaboard the HALCA satellite ceased towork just before the experiment. Never-theless, the terrestrially observed datawere correlated at the Penticton correla-tor in Canada. Signal-to-noise ratios of1253:1 were found between Arecibo andthe Green Bank 140-ft telescope, while310:1 resulted from the baseline betweenArecibo and Noto, Sicily.

On 02 Dec 98, Arecibo participatedin its first scheduled terrestrial VLBI formany years. This was organized to serveas a test session by a Russian team, co-ordinated by Igor Molotov, Sergey Likh-achev & Andrey Chuprikov (AstroSpace Center). The observations weremade at λ18 cm, with the targets includ-ing an OH/IR star, 2 pulsars and a qua-

Job Opportunity

RFI Engineer - Arecibo Observatory

Following completion of the Grego-rian Upgrade, the Arecibo Observa-

tory offers a much increased frequencycoverage and wider bandwidths to itsusers. However, given the recent explo-sion in global communications and theever-increasing usage of the radio spec-trum, achieving the full potential of the“new” telescope represents a challenge(for more information see, http://www.na i c . edu /~ tghosh / smarg /index.html). We invite applications fromqualified persons interested in joining theArecibo Observatory Electronics Depart-ment in its efforts to meet this challenge.

The successful candidate will worktowards minimizing emissions from on-site equipment; design, maintain andupgrade RFI monitoring and mobile de-tection equipment and organize search-es for sources of interference. To ensurecoexistence with other spectrum users,he/she will work with local spectrum

New Receiver Testing Laboratory

For a long time we have wanted to have a facility to allow us tomeasure system temperatures of low-noise-receivers for our tele-scope. We recently completed construction of this Receiver Test-ing Laboratory located near the Lidar Laboratory. Here, receiverscan be mounted on a table which can be jacked through an open-ing on the roof to get a clear view of the sky.

sar. The observations await correlationat Penticton.

Since HALCA’s return to observa-tions in Jan 1999, five 5-GHz observa-tions have been made as part of VSOPoperations. In these, the extragactic ob-jects, J0226+343, J0955+335,J1124+322, J1135+301 & J0911+338served as targets. The tapes recordedhave been sent to Penticton and Mitaka,Japan, for correlation.

Photo by Luis Murray

NAIC/AO NewsletterMarch 1999, Number 27 12

Jeffrey Hagen, Senior Scientific Pro-grammer Analyst at NRAO's 12m tele-scope in Tucson, AZ, has joined the AOComputer Department on leave fromNRAO for one year. He brings his con-siderable expertise in development ofreal-time control systems and VME-based data acquisition. We thank NRAOfor lending us Jeff's skills at a criticaltime in AO's post-Upgrade era.

Jean-Luc MargotJean-Luc Mar-got comes to thePlanetary RadarA s t r o n o m yGroup as a Post-Doc. He did hisPh.D. work atCornell Univer-sity under DonCambell, andcompleted histhesis entitled“Lunar Topography from Earth-basedRadar Interferometric Mapping.” Hesuccessfully defended his thesis on Feb.5, 1999. Soon after he moved here toArecibo.

Jean-Luc hails from Louvain Bel-gium, and he completed his 5-year de-gree in Electrical Engineering at theUniversity of Louvain, where he gradu-ated with “grande distinction” in June1993. He wrote an undergraduate the-sis on observations of atmospheric wa-ter vapor content using satellitemicrowave measurements.

His first observing proposal at Areci-bo is for the imaging of asteroid Golev-ka using radar interferometry techniques,an extension of his thesis work. WithMike Nolan, he plans to transmit fromArecibo, and to receive the radar echoessimultaneously at Arecibo and DSS-63in Madrid, Spain.

Jean-Luc comes to Puerto Rico withis wife, Karin, an electrical engineerworking for a local biomedical productscompany. Outside of their highly tech-

users and authorities both under the Pu-erto Rico Coordination Zone (PRCZ)agreement and in response to complaintsfrom telescope users. He/she will alsobe responsible for the maintenance andimprovements of our data and voicecommunication systems, including localand external networks.

Eligibility: The minimum qualifica-tion required is a BSE degree in electri-cal engineering, plus at least three yearsexperience in relevant areas. Good com-munication skills and a working knowl-edge of Spanish are highly desirable.

The Arecibo Observatory is part ofthe National Astronomy and IonosphereCenter, which is operated by CornellUniversity. AAE/EOE.

Send Applications to :Attn.: Human Resources DepartmentRFI EngineerARECIBO OBSERVATORYHC 3 Box 53995Arecibo, PR 00612

Deadline: April 15, 1999

Álvarez, conocido cariñosamente como“Tío Pino”, “Don José”, “Cheíto-tun-tún”, “El Jardinero”, “El Tórtolo”, etc.Siempre lo recordaremos por sus car-acterísticas Típicas, como por ejemplo:“¡amigo!”, “¡te quiero!”, “que lindo es-tás”, “que bien te ves” y por los abrazosa nuestra gente. Estuvo con nosotros en-tre febrero 21 del 1983 al 5 de marzo de1999. Le deseamos a nuestro queridocompañero, mucha salud, prosperidad ydisfrute en su jubilación.

An era ended at the Arecibo Observato-ry with the retirement of José LópezÁlvarez, affectionately known as “TíoPino” (uncle Pine), “Don José”, “Cheí-to-tun-tún”, “El Jardinero” (The Garden-er), “El Tórtolo” (The Dove), etc. Nearlyall who visit the Observatory for even ashort time have come to know our charm-ing gardener. Much missed will be hisshouts of: “¡amigo!”, “¡te quiero!” (I loveyou!), “que lindo estás” (how cute youare!), “que bien te ves” (how well youlook), and for his frequent and indiscrim-inate hugs. Don José joined the Obser-vatory February 21, 1983 and retired onMarch 5, 1999. We hope that our dearfriend will enjoy in his retirement muchhealth and prosperity. We dearly wishthat he comes to visit us frequently andsee, first and foremost, the work donehere by his hands.

New Arrivals

Jeffrey HagenArun Venkataraman

Don José

Pho

to b

y To

ny A

ceve

do

Comings and Goings

¡Se retira Don José!

Carmen Segarra and Jonathan Friedman

Recientemente se acogió al sistema deretiro nuestro compañero José López

Jean-Luc

NAIC/AO NewsletterMarch 1999, Number 27 13

nical workdays, Jean-Luc and Karin en-joy spelunking, a useful hobby in bothPuerto Rico and Belgium.

Gene Lauria

Gene recently moved permanently toArecibo as part of the “advance team”of the Ithaca Laboratory move. Genecame to NAIC in 1993. He has a Mas-ters’ of Engineering degree from the U.of Massachusetts, Amherst with a spe-ciality in Electromagnetics. The movedoes more than bring his large reservoirof electromagnetic expertise to the Ob-servatory site, it unites him with hisspouse, pulsar astronomer Kiriaki Xil-ouris in time for their first anniversary.