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TH




E JEWEL OF THE CARIBBEAN





THE MAJESTIC RADIO ASTRONOMY

CATHEDRAL


ARECIBO



FIRST VISIT NOV. 11, 1964


CLIMBED T-12
DETECTED RADIO EMISSION NGC 6720
ON A SINGLE TRANSIT AT 430 MHZ..




STAFF MEMBER AIO, JAN. 1, 1965



ARECIBO SUPERB SENSITIVITY

FOR FIVE DECADES.

UNTIL FAST AND THE SKA.





VERSITILE RADIO TELESCOPE



ARECIBO ALFA SURVEY OF RADIO RECOMBINATION LINES

YERVANT TERZIAN Cornell University April 9, 2012


RRL Active Group

· · · · · · · · Y.Terzian
E. Churchwell
R. Minchin
T. McIntyre
B. Liu
M.Lebron
J.Cersosimo
V.Pankonin
· · · · C.Salter
A. Roshi
A.Brazier
L.Anderson



Arecibo ALFA RRLs Group

Y. Terzian
M. Lebron
A. Deshpande
T. Bania
M. Goss
V. Pankonin
G. Joncas
E. Araya
P. Hofner
E. Churchwell
L. Anderson
V. Migenes
L. Staveley-Smith
J. Cersosimo
R. Brown
F. Lockman
M. Learner
P. Leahy
B. Lewis
C. Salter
C. Rodriguez Rico
C. Dickinson



MOTIVATION:

The aim is to produce the most sensitive RRL survey ever made of the galactic plane. Previously, only targeted observations have been performed primarily in the direction of HII regions.

This survey will fully sample the entire Galactic plane visible from Arecibo, and will provide organized data sets that will permit a wide range of science.





Research Areas of Special Interest: -HII regions -Planetary nebulae -Novae -Young massive star formation regions -Ionized stellar outflows -Diffuse ionized interstellar medium -PDRs


Radio Recombination lines in the L-Band (MHz)

n 174 173 172 171 170 169 168 167 166 165 164 163 H 1237.626 1259.150 1281.175 1303.718 1326.792 1350.414 1374.601 1399.368 1424.734 1450.716 1477.335 1504.608 He 1238.130 1259.663 1281.698 1304.249 1327.333 1350.965 1375.161 1399.938 1425.314 1451.308 1477.937 1505.221 C 1238.243 1259.778 1281.815 1304.368 1327.454 1351.088 1375.286 1400.066 1425.445 1451.440 1478.072 1505.359


Contour map of the continuum emission of the galactic plane at 1.4 GHz for 12є < l < 25є and |b| < 4 measured with Effelsberg 100-m telescope (Altenhoff et al. 1970). The image is in galactic coordinates, and the HPBW ~


POSS image of the star-forming region Sharpless 88 (left). Radio recombination lines observations of 5 GHz toward the compact HII region S 88 with the Arecibo telescope (right). Hydrogen, helium, and carbon 109 were clearly detected, and hydrogen and helium 137 we well. C109line is clearly stronger than helium lines. Next to the carbon line is the heavy elements line. This spectra was taken in 45 minutes of integration.


Possible Outcomes:
-Two (three) dimensional velocity structure from RRL profiles, information on turbulent motions, bulk motions of outflows, rotation, expansion, contraction and shocks. -A direct determination of electron temperature distributions across extended ionized regions, and across the galactic plane. -The electron density distribution via non-LTE analysis of all detected objects, and its distribution across the Galactic plane.


-The distribution and relative abundances of ionized He, C, and heavier elements. -The study of photodissociation regions (PDRs) via Carbon RRLs in the transition regions between ionized and neutral gas. -Large scale structure of the Milky Way part seen from Arecibo.


-The structure of the Diffuse Galactic Ionized Medium, its physical parameters and its distribution. -RRLs Survey comparison with many other surveys, such as 2MASS, ISO, MSX, NVSS, ALFA Continuum, ALFA HI Survey. -High probability of serendipitous discoveries from a fully sampled galactic survey.


Radio recombination lines at 1.4 GHz measured with the Arecibo telescope (Silverglate & Terzian 1978). Each spectra took between 30 and 60 minutes of on-source time. The hydrogen line is clearly visible in all spectra, and carbon line show up very bright in W84, S87, and S88.


A sequence of H166 line profiles taken along the Galactic plane at longitudes marked in each spectrum. The vertical scale is antenna temperature in Kelvins at the NRAO 140-ft


Comensal Survey with PALFA

· Sample the Galactic Plane (±1° North and South of the mid-plane).
· Integration time 5 minutes per sky position.
· Observe 12 alpha lines simultaneously.
· Spectrometer (300 MHz BW total).
· Spectral Resolution ~ 4 ­ 5 km/s.











FOR ARECIBO

I HOPE THE BEST

IS YET TO COME