We report the results of our systematic survey for Galactic 6.7 GHz Class II CH 3 OH maser emission toward a sample of young stellar objects. The survey was conducted with the Shanghai Tianma Radio Telescope (TMRT). The sample consists of 3348 sources selected from the all-sky Wide-Field Infrared Survey Explorer (WISE) point source catalog. We have discussed the selection criteria in detail and the detection results of those at high Galactic latitudes (i.e. |b| > 2 • ) in a previous paper (paper I). Here, we present the results from the survey of those at low Galactic latitudes, i.e. |b| < 2 • . Of 1875 selected WISE point sources, 291 positions that were actually associated with 224 sources were detected with CH 3 OH maser emission. Among them, 32 are newly detected. Majority of the newly detected sources are associated with bright WISE sources. The majority of the detected sources (209/224 = 93.3%) are quite close to the Galactic Plane (|b| < 1 • ) and lie on the inner spiral arms with positive LSR velocities. Detection rate and the color-color distribution of our detection are all matched with our anticipation. Combining with detections from previous surveys, we compile a catalogue of 1085 sources with 6.7 GHz CH 3 OH maser emission in our Galaxy.

We present observations of the C-band 1 10 − 1 11 (4.8 GHz) and Ku-band 2 11 − 2 12 (14.5 GHz) K-doublet lines of H 2 CO and the C-band 1 10 − 1 11 (4.6 GHz) line of H 2 13 CO toward a large sample of Galactic molecular clouds, through the Shanghai Tianma 65-m radio telescope (TMRT). Our sample with 112 sources includes strong H 2 CO sources from the TMRT molecular line survey at C-band and other known H 2 CO sources. All three lines are detected toward 38 objects (43 radial velocity components) yielding a detection rate of 34%. Complementary observations of their continuum emission at both C-and Ku-bands were performed. Combining spectral line parameters and continuum data, we calculate the column densities, the optical depths and the isotope ratio H 2 12 CO/H 2 13 CO for each source. To evaluate photon trapping caused by sometimes significant opacities in the main isotopologue's rotational mm-wave lines connecting our measured K-doublets, and to obtain 12 C/ 13 C abundance ratios, we used the RADEX non-LTE model accounting for radiative transfer effects. This implied the use of the new collision rates from Wiesenfeld & Faure (2013). Also implementing distance values from trigonometric parallax measurements for our sources, we obtain a linear fit of 12 C/ 13 C = (5.08±1.10)D GC + (11.86±6.60), with a correlation coefficient of 0.58. D GC refers to Galactocentric distances. Our 12 C/ 13 C ratios agree very well with the ones deduced from CN and C 18 O but are lower than those previously reported on the basis of H 2 CO, tending to suggest that the bulk of the H 2 CO in our sources was formed on dust grain mantles and not in the gas phase.

We report Shanghai Tian Ma Radio Telescope detections of several long carbonchain molecules at C and Ku band, including HC 3 N, HC 5 N, HC 7 N, HC 9 N, C 3 S, C 6 H and C 8 H toward the starless cloud Serpens South 1a. We detected some transitions (HC 9 N J=13-12 F=12-11 and F=14-13, H 13 CCCN J=2-1 F=1-0 and F=1-1, HC 13 CCN J=2-1 F=2-2, F=1-0 and F=1-1, HCC 13 CN J=2-1 F=1-0 and F=1-1) and resolved some hyperfine components (HC 5 N J=6-5 F=5-4, H 13 CCCN 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±0.15):(1.47±0.18) for [H 13 CCCN]:[HC 13 CCN]:[HCC 13 CN]. This result implies that the 13 C isotope is also concentrated in the carbon atom adjacent to the nitrogen atom in HC 3 N in Serpens south 1a, which is similar to TMC-1. The [HC 3 N]/[H 13 CCCN] ratio of 78±9, the [HC 3 N]/[HC 13 CCN] ratio of 70±8, and the [HC 3 N]/[HCC 13 CN] ratio of 53±4 are also comparable to those in TMC-1. In any case, Serpens South 1a proves a testing ground for understanding carbon-chain chemistry.

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We report the detection of widespread CH 2 OHCHO and HOCH 2 CH 2 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.

In this paper, we report radio observations of the Galactic Center magnetar PSR J1745−2900 at six epochs between June and October, 2014. These observations were carried out using the new Shanghai Tian Ma Radio Telescope at a frequency of 8.6 GHz. Both the flux density and integrated profile of PSR J1745−2900 show dramatic changes from epoch to epoch showing that the pulsar was in its "erratic" phase. On MJD 56836, the flux density of this magnetar was about 8.7 mJy, which was ten times large than that reported at the time of discovery, enabling a single-pulse analysis. The emission is dominated by narrow "spiky" pulses which follow a log-normal distribution in peak flux density. From 1913 pulses, we detected 53 pulses whose peak flux density is ten times greater than that of the integrated profile. They are concentrated in pulse phase at the peaks of the integrated profile. The pulse widths at the 50% level of these bright pulses was between 0.2 • to 0.9 • , much narrower than that of integrated profile (∼12 • ). The observed pulse widths may be limited by interstellar scattering. No clear correlation was found between the widths and peak flux density of these pulses and no evidence was found for subpulse drifting. Relatively strong spiky pulses are also detected in the other five epochs of

We performed a systematic 6.7 GHz Class II methanol maser survey using the Shanghai Tianma Radio Telescope toward targets selected from the all-sky Wide-Field Infrared Survey Explorer (WISE) point catalog. In this paper, we report the results from the survey of those at high Galactic latitudes, i.e. |b| > 2 • . Of 1473 selected WISE point sources at high latitude, 17 point positions that were actually associated with 12 sources were detected with maser emission, reflecting the rarity (1−2%) of methanol masers in the region away from the Galactic plane. Out of the 12 sources, 3 are detected for the first time. The spectral energy distribution (SED) at infrared bands shows that these new detected masers occur in the massive star forming regions. Compared to previous detections, the methanol maser changes significantly in both spectral profiles and flux densities. The infrared WISE images show that almost all of these masers are located in the positions of the bright WISE point sources. Compared with the methanol masers at the Galactic plane, these high-latitude methanol masers provide good tracers for investigating the physics and kinematics around massive young stellar objects, because they are believed to be less affected by the surrounding cluster environment.

We have conducted a line survey toward Orion KL using the Q-band receiver of the Tianma 65 m radio telescope (TMRT), covering 34.8–50 GHz with a velocity resolution between 0.79 and 0.55 km s−1, respectively. The observations reach a sensitivity of the level of 1–8 mK, proving that the TMRT is sensitive for conducting deep-line surveys. In total, 597 Gaussian features are extracted. Among them, 177 radio recombination lines (RRLs) are identified, including 126, 40, and 11 RRLs of hydrogen, helium, and carbon, with a maximum Δn of 16, 7, and 3, respectively. The carbon RRLs are confirmed to originate from photodissociation regions with a V LSR ∼ 9 km s−1. In addition, 371 molecular transitions of 53 molecular species are identified. Twenty-one molecular species of this survey were not firmly detected in the Q band by Rizzo et al., including species such as H2CS, HCOOH, C2H5OH, H 2 13 CO, H2CCO, CH3CHO, CH2OCH2, HCN υ 2 = 1, and CH3OCHO υ t = 1. In particular, the vibrationally excited states of ethyl cyanide (C2H5CN υ13/υ21) are for the first time firmly detected in the Q band. NH3 (15,15) and (16,16) are identified, and they are so far the highest transitions of the NH3 inversion lines detected toward Orion KL. All of the identified lines can be reproduced by a radiative transfer model.