NATIONAL RADIO ASTRONOMY OBSERVATORY OBSERVING SUMMARY-1989 STATISTICS February 1990 Cover The Radio Galaxy Fornax A The cover photograph is a superposition of the VLA radio emission (shown as red) from the radio galaxy Fornax A and the visible light in the vicinity of NGC 1316 (shown as blue-white). The two main radio emitting lobes are produced by relativistic electrons in magnetic fields which have been transported hundreds of thousands of light years outward from the elliptical galaxy NGC 1316 which lies between the two regions. The energy for the relativistic flow apparently was provided by the gravitational capture of small galaxies by NGC 1316. The shock waves and trails of the infallen galaxies produce the features in the radio lobes seen as filaments and rings. The small galaxy near NGC 1316 may soon be captured. Observation details: Observers: E. Fomalont (NRAO), R. Ekers (Australia Telescope), K. Ebneter and W. Van Breugel (U. California) Frequency of 1.384 GHz; five hours of D-configuration and five hours of C-configuration Resolution of 15"; field of view is 60' x 40' NATIONAL RADIO ASTRONOMY OBSERVATORY OBSERVING SUMMARY 1989 STATISTICS FEBRUARY 1990 SOME HIGHLIGHTS OF THE 1989 RESEARCH PROGRAM A second Einstein Ring has been identified from new A-configuration VLA observations of MG1652+138, the second candidate for an Einstein ring gravitational lens system to be selected from the MIT-Green Bank 5 GHz survey. Optical images and spectra established the redshift of a faint blue quasar between the two radio sources, while the VLA results have both detected the quasar core at its optical location and improved the ring image quality. The Einstein ring is thought to be the gravitationally lensed image of one of the quasar's radio lobes by an intervening galaxy. The VLA successfully observed a radar bounce from Saturn's largest satellite, Titan. The 8.6 GHz signals were transmitted from the 70-meter DSN Goldstone antenna and received 2.5 hours later at the VLA. The radar echo from Titan- is the weakest such echo ever measured. Differences in surface reflectivity from day to data indicate a highly variable surface on Titan, while the low reflectivity could indicate the presence of a deep ethane ocean. HI observations made with the Areclbo and 140-ft telescopes of the unique galaxy Mai in 1 have shown it to contain an enormous HI disk, of diameter greater than 240 kpc, and mass in excess of 1011 solar masses, making it the largest HI mass of any known galaxy. The low optical surface brightness indicates that Malin 1 has extremely inefficient star formation. It appears to be an unevolvlng disk galaxy whose surface mass density is so low that the chemical composition and mass fraction in gas change very slowly over Hubble times. Interstellar C^D has been detected at 17.6 GHz at the 140-ft, with signal strengths of only a few milli-kelvin, representing a considerable technical feat. Deuterated species are important diagnostics of interstellar ion-molecule chemistry. The observed C4D/C4H abundance ratio is consistent with model predictions, and confirms the expectation that the ratio decreases as the number of carbon atoms in the molecule increases. However, C4D/C4H is only about 5 percent of the C3HD/C3H2 ratio, indicating a problem in the current understanding of the ring species €3^. CO has been detected by the 12-meter telescope in the nearby Sc galaxy M33. Although HI has been long known in M33, previous studies suggested that the molecular gas content was low. A map of the CO emission reveals several large, unbound, molecular clouds, and a relative content of molecular to atomic gas comparable with that in our own galaxy. However, the total mass of M33 is considerably less than the Milky Way, which accounts for the weak CO emission and the difficulty of the long search. In 1989 September the VLA was used in support of the launch of the Normal Incidence X-ray Telescope (NIXT), which provides X-ray images of the sun's corona at one arcsecond resolution. The VLA discovered a powerful flare near the center of the sun's disk, with up to 100 percent circular polarization, and a maximum brightness temperature in excess of 1010 K. These properties are indicative of coherent emission processes (cyclotron maser or plasma radiation). The VLA has performed the first direct image of such a coherent microwave source. Together with the NIXT, Solar Maximum Mission satellite, and ground-based optical observations, the coherent emission mechanism may be identified with a high degree of confidence. Observing Hours 1977 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 Calendar Year 300-Foot MO-Foot iH 12Meter ("31 Interferometer I \VLA Fig. 1. This figure shows the hours scheduled for observing on each telescope during the last decade. Distribution of Scheduled Observing Time 12-Meter 140-Foot VLA o o o o3 1980 81 82 83 84 85 86 87 88 89 1980 81 82 83 84 85 86 87 88 89 1981 82 83 84 85 86 87 88 89 Calendar Year Calendar Year Calendar Year NRAO Staff | Visitors m Testing and Calibration Fig. 2. These graphs show the number of hours scheduled for calibration and for observing by the NRAO staff and by visitors on each telescope system during the last decade. 12-Meter Radio Telescope Summary 1980 I98l 1982 1983 I984 1985 1986 I987 I988 1989 Calendar Year •Observing Installation, Maintenance and Calibration Equipment Failure, Weather and Interference Fig. 3. This summary for each quarter of the calendar year shows the percentage of time the telescope was scheduled for observing; for routine calibration, maintenance, and Installation of new experiments; and the percentage of time lost due to equipment failure, bad weather, and radio interference. The telescope is removed from service for a period of 4-6 weeks each summer during the wet season. This period is used for maintenance and upgrading of the Instrument. During the last half of 1982 and most of 1983 the telescope was out of service for the replacement of the reflecting surface and its backup structure. 140-Foot Radio Telescope Summary 100 ■ I - /~ -s - ^\ /"■ ^ s^ ^ ^' y s^ \ ^N y /s •s LV A /"" / 80 > vN^ V i IV X> s V.- /* V V "^^ y f V / V • / N 60 •\ i vyV ' V - 40 A A - " / ! \ A 20 ^ ^7 \ r/s > \ y V V s - 5k- -< 4 ^ . ^ .-. 4 '•»••■ x^. ^-. s 0 \- '"1 -i —J ^1 -mm* 1980 1981 1982 1983 1984 1985 1986 1987 1988 1989 Calendar Year Observing Installation, Maintenance and Calibration Equipment Failure, Weather and Interference Fig. 4. This summary for each quarter of the calendar year shows the percentage of time the telescope was scheduled for observing; for routine calibration, maintenance, and installation of new experiments; and the percentage of time lost due to equipment failure, bad weather, and radio interference. Major improvements to the telescope system include: 1980 - installation of the Model IV autocorrelation receiver; 1982 - beam efficiency and pointing tests at 1.3 cm; 1983 - brake overhaul and installation of the second channel of the upconverter/maser receiver; 1987 - holographic surface tests and panel readjustments. Very Large Array Telescope Summary 100 - - 80 '**" 1 ^ \ ^S — — ^^ -^ — s ^ ^s ^ ^. - /^ »sX *- " - V /" ^ 60 / *s a> o r "^> f - 40 tr ^ st V A v. S r* ^ - v_ — — —■ ^ _ —^ ^- ^_ r N , / ^s X\ 20 , - ** s« _ * ^N "^ \ s 'x_ .-. >*^. .-. — v^ ^^« • —. •« . —- —- ..»- .-« ■ ._. .— ... .__. .— -> ._. .-• »^- '- —.. 0 V Calendar Year Construction Observing Testing, Maintenance and Calibration Downtime Fig. 5. This summary for each quarter of the calendar year shows the percentage of time the telescope was scheduled for observing; for routine system testing, maintenance, and calibration; and the percentage of time lost due to hardware or software failure, power failure, or bad weather. Time scheduled for completion of the construction was reduced to zero after the first quarter of 1981. Full-Time Permanent Employees 500 1976 1977 1978 1979 1980 1981 1982 1983 1984 1985 1986 1987 1988 1989 1990 1991 Calendar Year Fig. 6. This figure shows the total number of NRAO full-time, permanent employees at the end of each year, projected into the future. Number of People Observing with NRAO Telescopes 1000 I J 950 $8® Visitors and Students ~ - 900 V/A Research Associates - ■1 Permanent Staff 850 est. - - f^H Number of Institutiom t 1 - 800 i^< _, 1 M 750 H^ XW S^: em ^ 1 ^ 1 - 700 mi -m- — £$ — 1 ^ 1 650 I888E i m — M —-1- :•&# m ffl 1 : : : : $ S« : : : : : $S •ip ^ ■ 600 ili m M j^ ^ : ■x-x 1 m :W: m m ^ II . iW: 4fe$ i^ M w550 m m m m - m m 1 ^ X*5S £500 i i W i m ^ ii - m Z x-i'i* 81 450 ii 1 m 1 i m - M ■%•■•' m 1 M P •^•: ^ 400 : : : : _ ;:;.;•:•; •:W: « •x-x : : : : , •:•:?: m II M XWl*v. 350 X'X? m ^i -§- :•!•:•:•: e.:.;:si -I- S::§ S$s — : : : 1 1 — — m ■ .-•-.-.-. ■■ 1 "" ■" .••••*.•. "■ " !•'•■•'• ■'" I ■ ■ ■X'X* '" " 300 V.V.' • *•"•*. .••••••", "••••X I•:•»: m : : x " : :•;•£ ;•;•>>; x-x - ■ m :•:•?>: M $•& S$S ^ : jsS $8$. — m m —#$:—m m M :5¥: : 250 •:■:•;•■. Mi — M — M': : : m m m ; : : : ; sn -»- :?:•:: « ^ X'X' •Xv! :«•:■ ~w- vXv ::«• :¥:% ■x^x :?& ft?: :%¥ ': : :": && : : :: — 200 '.•'.''.•'.'_ """ 'X^v :-::xj ■ $•§■! """ - M ^ '.•'.''.•'.• M M~-m- — SS — -»- I^S pr •Xvl" Ii- 150 M ^ M. ^ ■* ivi'i*" M F %•;•! •.v.v !_PF 100 - ill •:•;•:■:' !? — iirSii: - 4 ^5" T~ 1 :| n n :?:§ * >ivi — !&&■.¥ .• — ^ ■ =? 50 ' — — — ■ ; ~M' : 5*^* "I". —;.:J.:J ■ _l|. _ 22. 7$ M tf i ' 0' i 1975 1976 1977 1978 1979 1980 1981 1982 1983 1984 1985 1986 1987 1988 1989 1990 Calendar Year Fig.