Jinqing Wang

Locating positions of γ-ray-emitting regions in blazars

We propose a new method to locate the gamma-ray-emitting positions R gamma from the measured time lags tau(ob) of gamma-ray emission relative to broad emission lines. The method is also applicable to lower frequencies. R-gamma depends on parameters tau(ob), R-BLR, upsilon(d) and theta, where R-BLR is the size of the broad-line region, upsilon(d) is the travelling speed of disturbances down the jet and theta is the viewing angle of the jet axis to the line of sight. As tau(ob) = 0, tau(ob) 0, the broad lines zero-lag, lag or lead the gamma-rays, respectively. It is applied to 3C 273, in which the lines and the radio emission have enough data, but the gamma-rays do not. We find tau(ob) 0 for the 5, 8, 15, 22 and 37 GHz emission relative to the broad lines H alpha, H beta and H gamma. The lag may be positive or negative; however, current data do not allow discrimination between the two cases. The measured lags are of the order of years. For a given line, tau(ob) generally decreases as radio frequency increases. This trend most likely results from the radiative cooling of relativistic electrons. The negative lags have an average of tau(ob)= -2.86 yr for the 37 GHz emission, which represents the lines lagging the radio emission. The positive lags have tau(ob) = 3.20 yr, which represents the lines leading the radio emission. We obtain the radio-emitting positions R-radio = 0.40-2.62 pc and R-radio = 9.43-62.31 pc for the negative and positive lags, respectively. From the constraint of R-gamma less than or similar to R-radio, we have R-gamma less than or similar to 0.40-2.62 pc for the negative lags. For the positive lags, 4.67-30.81 < R-gamma less than or similar to 9.43-62.31 pc. These estimated R-gamma are consistent with those of other studies. These agreements confirm the reliability of the method and assumptions. The method may also be applicable to BL Lacertae objects, in which broad lines were detected.

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:(1.11pm0.15):(1.47pm0.18) 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 78pm9, the [HC3N]/[HC13CCN] ratio of 70pm8, and the [HC3N]/[HCC13CN] ratio of 53pm4 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

A Q-band two-beam cryogenic receiver for the Tianma Radio Telescope

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Design and testing for phase stabilized based on optical fiber

OHCHO and HOCH

TMRT Observations of 26 Pulsars at 8.6 GHz

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Correcting Gravitational Deformation at the Tianma Radio Telescope

CH

Single-sideband baseband convertor

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Digital phase calibrating unit machine

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.

Realization method of double-passage real-time relevance machine

A Q-band two-beam cryogenic receiver for the Tianma Radio Telescope (TMRT) has been developed, and it uses the independently-developed key microwave and millimeter-wave components operating from 35 to 50GHz with a fractional bandwidth of 35%. The Q-band receiver consists of three parts: optics, cold unit assembly and warm unit assembly, and it can receive simultaneously the left-handed and right-handed circularly polarized waves. The cold unit assembly of each beam is composed of a feed horn, a noise injection coupler, a differential phase shifter, an orthomode transducer and two low-noise amplifiers, and it works at a temperature range near 20 K to greatly improve the detection sensitivity of the receiving system. The warm unit assembly includes four radio-frequency amplifiers, four radio-frequency high-pass filters, four waveguide biased mixers, four 4–12 GHz intermediate-frequency amplifiers and one 31–38 GHz frequency synthesizer. The measured Q-band four-channel receiver noise temperatures are roughly 30–40 K. In addition, the single-dish spectral line and international very long baseline interferometry (VLBI) observations between the TMRT and East Asia VLBI Network at the Q-band have been successfully carried out, demonstrating the advantages of the TMRT equipped with the state-of-the-art Q-band receiver.