NATIONAL RADIO ASTRONOMY OBSERVATORY Observing Summary - 1984 Statistics February 1985 NATIONAL RADIO ASTRONOMY OBSERVATORY Observing Summary - 1984 Statistics February 1985 Some Highlights of the 1984 Research Program • The 300-foot telescope was used to detect low-frequency carbon recombination lines from cold, diffuse Interstellar clouds in the direction of Cas A. Previously reported absorption lines were confirmed at 26 MHz and a number of other lines were identified in the 25 MHz to 68 MHz range. These lines promise to become an important diagnostic for the ionization conditions in cool interstellar clouds. • Extremely painstaking observations of several Abell clusters of galaxies with the 140-foot telescope have yielded three positive detections of the Sunyaev-Zeldovich effect. The dimunition in the brightness of the microwave background in the direction of clusters is the direct result of the Inverse Compton scattering of the 3° K blackbody photons by electrons in the Intracluster gas. The observations took full advantage of the low noise temperature, broadband, and excellent stability of the Green Bank 18-26 MHz maser system. • The J ■ 1*0 transition of the long-sought-after molecular ion, HCNff*", was detected with the 12-meter telescope at 74.1 GHz. The existence of protonated HCN is one of the prime tests of the theory of ion-molecule reaction schemes in interstellar chemistry. Virtually all CN-containing interstellar molecules, such as HCN, HNC, and many long-chain cyanopolyynes, form directly from HCNH+. • A high-resolution VLA survey of all catalogued, high surface brightness, compact objects in the southern galactic plane uncovered a few objects which are not classifiable into previously known SNR categories. The peculiar axisymmetric source morphologies exhibit filamentary, nonthermal emission and spectral indices intermediate between shell- and Crab-like remnants and seem to represent a new class of nonthermal radio sources. • VLA monitoring of the brightest radio sources in M82 over the past three years has detected rapid luminosity decay on the scale of only a few years. The sources are interpreted as decaying supernovae associated with the starburst source of energy and massive star formation in M82fs nucleus. The rate of supernova production in the inner nucleus of M82 is approximately 50 times higher than for the entire disk of our galaxy, and the individual sources are up to 150 times brighter than Cas A. • The radio galaxy 3C 75 at the center of the cluster Abell 400 has been identified as the source of four jets originating from a double nucleus. Intercomparison of the high resolution VLA maps with detailed optical and X-ray images of the galaxy and cluster suggest that the jets may be powered from their interaction with the turbulent gas in the cluster as well as from an "engine" at the center of 3C 75. Observing Hours 40 est. est. est. est. est. est. 1975 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 Calendar Year 1300-Foot 140-Foot B 12-Meter WM Interferometer WhVLA 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 300-Foot VLA :y ■il I I Ill■I. 1975 76 77 78 79 80 81 82 83 84 1975 76 77 78 79 80 81 82 83 84 1975 76 77 78 79 80 81 82 83 84 1981 82 83 84 Calendar Year Calendar Year Calendar Year Calendar Year \NRAO Staff I Visitors I 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 o 1975 1976 1977 1978 1979 1980 1981 1982 1983 1984 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 1 •^ ^ — - - "N r ^ / ^ 'N , /■ /\ 80 / V V.^ ys. n v. ^ "V y s^ \i ^s / \ y^ A h V 1 -^ /' s? - s/ ! V / \J V N vy v- 60 \ V - - / A 40 i\ - A - A / w A / / /*s 20 /N \< A • V X 'N s v ^N J v\ y V *s J \/ i_ ■>»< v- 7 ^ 0 rr: ^C .—^ .^'~'^. V.^' 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: 1974 - installation of the maser Cassegrain system; 1977 - data processing computer and installa¬ tion of the maser Cassegrain system; 1978 - tests of the deformable subreflector; 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. 300-Foot Radio Telescope Summary 100 A V -\ /^ N^ ^\ *- - •s " ^ ■"^ ^ ss ^ /~ A > /"" - - "S V V V Jm r V y 80 •^ A 1r \,V - - \ / ■£ 60 a> V ofc- - - a> ^ 40 { \ - - / A 20 J A s\ / "N A A /s y -/ V - - - ^ ^ .y S- —■ ^ \_ - -■ — : . * ^ 7 V J, -" 0 ± Calendar Year • Observing • Installation, Maintenance and Calibration Equipment Failure, Weather and Interference Fig. 5. 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. During 1980 a new traveling feed was installed, and in 1983 cables were replaced and the telescope was painted. Very Large Array Telescope Summary 1977 1978 1979 1980 1981 1982 1983 1984 Calendar Year Construction Initial Observing and Testing Observing Testing, Maintenance and Calibration Downtime Fig. 6. 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. During 1977 and 1978 no distinction was made between astronomical and test observing. Time scheduled for completion of the construction was reduced to zero after the first quarter of 1981. Full-Time Permanent Employees 450 400 ffifaVLA Construction 350 ■I Research and Operations I \VLBA Construction 300 fc250 rssst 'sw -ssss.vwx. rssssrsssj ^ 200 150 100 50 0 1957 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 v v Fiscal Year Calendar Year Fig. 7. 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 1959 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 Calendar Year Fig. 8. This bar chart shows for each calendar year the number of NRAO permanent research staff and the number of research associates who use the telescopes. In addition, it shows the total number of visitor-users of NRAO telescopes and the number of institutions from which the NRAO visitors come. The significant jump in these last two categories for 1981 reflects the increased use of the VLA. Distribution of Telescope Time by Per Cent 12-meter 140-foot 300-foot VLA 1984 Summary Visitors 46% 60% 48% 56% 53% Students 4% 9% 28% 9% 12% Permanent Staff 10% 12% 10% 7% 10% Research Associates 0% 1% 5% 3% 2% Tests and Calibrations 15% 6% 0% 16% 9% Maintenance and Installation 23% 10% 7% 8% 12% Holidays and Unscheduled 1% 2% 2% 1% 2% 10 Distribution of Scheduled Observing Programs in Various Research Areas, by Percent 12-meter 140-foot 300-foot VLA Overall I. SOLAR SYSTEM — Sun, Planets, Satellites, and Comets 3% 2% 4% 5% 4% II. STELLAR Pulsars, X-ray Sources, Planetary Nebulae, 23% 9% 11% 22% 16% Circumstellar Shells, Supernova Remnants, Masers, Novae, Supernovae, and Stars III. GALACTIC Galactic Structure, Center, Molecular 45% 22% 19% 23% 27% Clouds, HII Regions, Star Formation, Molecules, and Interstellar Medium IV. EXTRAGALACTIC — Normal and Active Galaxies, Radio Galaxies, 29% 67% 66% 50% 53% Clusters, Quasars, VLB Studies, Extra- galactic Molecules, and Cosmology 11 Institutions from which Visitors Came to Use NRAO Telescopes during 1984 Telescope Institution 12-m 140-ft 300-ft VLA 1. Anglo Australian Observatory X 2. Alabama U. of X 3. Arcetri Ap. Obs. (Italy) X 4. Arizona U. of - Steward, L & P Lab. x X 5. Barcelona U. of (Spain) x 6. Battelle Northwest Labs. 7. Bell Labs. (N.J.) 8. Besancon Obs. (France) 9. Birmingham U. of (UK) 10. Bologna U. of (Italy) 11. Boston U. x 12. Brandeis Univ.