Rong-Bing Zhao

TMRT OBSERVATIONS OF CARBON-CHAIN MOLECULES IN SERPENS SOUTH 1a

We report Shanghai Tian Ma Radio Telescope detections of several long carbon-chain molecules at C and Ku band, including HC3N, HC5N, HC7N, HC9N, C3S, C6H and C8H toward the starless cloud Serpens South 1a. We detected some transitions (HC9N J=13-12 F=12-11 and F=14-13, H13CCCN J=2-1 F=1-0 and F=1-1, HC13CCN J=2-1 F=2-2, F=1-0 and F=1-1, HCC13CN J=2-1 F=1-0 and F=1-1) and resolved some hyperfine components (HC5N J=6-5 F=5-4, H13CCCN J=2-1 F=2-1) for the first time in the interstellar medium. The column densities of these carbon-chain molecules in a range of 10^{12}-10^{13} cm^{-2} are comparable to two carbon-chain molecule rich sources, TMC-1 and Lupus-1A. The abundance ratios are 1.00:(1.11\pm0.15):(1.47\pm0.18) for [H13CCCN]:[HC13CCN]:[HCC13CN]. This result implies that the 13C isotope is also concentrated in the carbon atom adjacent to the nitrogen atom in HC3N in Serpens south 1a, which is similar to TMC-1. The [HC3N]/[H13CCCN] ratio of 78\pm9, the [HC3N]/[HC13CCN] ratio of 70\pm8, and the [HC3N]/[HCC13CN] ratio of 53\pm4 are also comparable to those in TMC-1. In any case, Serpens South 1a proves a testing ground for understanding carbon-chain chemistry.

Widespread Presence of Glycolaldehyde and Ethylene Glycol around Sagittarius B2

We report the detection of widespread CH

Simultaneous 13 cm/3 cm Single-pulse Observations of PSR B0329+54

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Pulsar studies with Shanghai tian ma radio telescope

OHCHO and HOCH

TMRT Observations of 26 Pulsars at 8.6 GHz

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Investigating the multifrequency pulse profiles of PSRs B0329+54 and B1642–03 in an inverse Compton scattering model

CH

SINGLE-PULSE RADIO OBSERVATIONS OF THE GALACTIC CENTER MAGNETAR PSR J1745-2900

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Progress of Wideband VLBI Digital System Development at SHAO

OH emission in Galactic center giant molecular cloud Sagittarius B2 using the Shanghai Tianma 65m Radio Telescope. Our observations show for the first time that the spatial distribution of these two important prebiotic molecules extends over 15 arc-minutes, corresponding to a linear size of approximately 36 pc. These two molecules are not just distributed in or near the hot cores. The abundance of these two molecules seems to decrease from the cold outer region to the central region associated with star-formation activity. Results present here suggest that these two molecules are likely to form through a low temperature process. Recent theoretical and experimental studies demonstrated that prebiotic molecules can be efficiently formed in icy grain mantles through several pathways. However, these complex ice features cannot be directly observed, and most constraints on the ice compositions come from millimeter observations of desorbed ice chemistry products. These results, combined with laboratory studies, strongly support the existence of abundant prebiotic molecules in ices.

Digital phase calibrating unit machine

We have investigated the mode-changing properties of PSR B0329+54 using 31 epochs of simultaneous 13 cm/3 cm single-pulse observations obtained with Shanghai Tian Ma 65 m telescope. The pulsar was found in the abnormal emission mode 17 times, accounting for ~13% of the 41.6 hours total observation time. Single pulse analyses indicate that mode changes took place simultaneously at 13 cm/3 cm within a few rotational periods. We detected occasional bright and narrow pulses whose peak flux densities were 10 times higher than that of the integrated profile in both bands. At 3 cm, about 0.66% and 0.27% of single pulses were bright in the normal mode and abnormal mode respectively, but at 13 cm the occurrence rate was only about 0.007%. We divided the pulsar radiation window into three components (C1, C2 and C3) corresponding to the main peaks of the integrated profile. The bright pulses preferentially occurred at pulse phases corresponding to the peaks of C2 and C3. Fluctuation spectra showed that C2 had excess red noise in the normal mode, but broad quasi-periodic features with central frequencies around 0.12 cycles/period in the abnormal mode. At 3 cm, C3 had a stronger quasi-periodic modulation centered around 0.06 cycles/period in the abnormal mode. Although there were some asymmetries in the two-dimensional fluctuation spectra, we found no clear evidence for systematic subpulse drifting. Consistent with previous low-frequency observations, we found a very low nulling probability for B0329+54 with upper limits of 0.13% and 1.68% at 13 cm/3 cm respectively.

Realization method of double-passage real-time relevance machine

A 65 m diameter full-steerable radio telescope TMRT with the frequency coverage from 1.25 to 50.0 GHz is newly built at Shanghai. To satisfy the demands of the pulsar and spectral line observations, a Digital Backend System (DIBAS) was built for this telescope. The DIBAS can support both the pulsar search and online folding pulsar observation. Either the coherent or incoherent dedispersion pulsar observation mode can be chosen according to demand of observers. The testing pulsar observation results showed that the pulsar observation system works well. A series of pulsar projects (such as pulsar timing, hunting, VLBI, etc) are carried out with the TMRT. Some important findings are expectable in the future.