Spectral line survey observations are conducted toward the high-mass protostar candidate NGC 2264 CMM3 in the 4 mm, 3 mm, and 0.8 mm bands with the Nobeyama 45 m telescope and the Atacama Submillimeter Telescope Experiment (ASTE) 10 m telescope. In total, 265 emission lines are detected in the 4 mm and 3 mm bands, and 74 emission lines in the 0.8 mm band. As a result, 36 molecular species and 30 isotopologues are identified. In addition to the fundamental molecular species, many emission lines of carbon-chain molecules such as HC 5 N, C 4 H, CCS, and C 3 S are detected in the 4 mm and 3 mm bands. Deuterated molecular species are also detected with relatively strong intensities. On the other hand, emission lines of complex organic molecules such as HCOOCH 3 , and CH 3 OCH 3 are found to be weak. For the molecules for which multiple transitions are detected, rotation temperatures are derived to be 7-33 K except for CH 3 OH. Emission lines with high upper-state energies (E u > 150 K) are detected for CH 3 OH, indicating existence of a hot core. In comparison with the chemical composition of the Orion KL, carbon-chain molecules and deuterated molecules are found to be abundant in NGC 2264 CMM3, while sulfur-bearing species and complex organic molecules are deficient. These characteristics indicate chemical youth of NGC 2264 CMM3 in spite of its location at the center of the cluster forming core, NGC 2264 C. Subject headings: stars: formation -ISM: individual(NGC 2264) -ISM: molecules 2. Observation 2.1. Observation with Nobeyama 45 m NGC 2264 CMM3 was observed in the 4 mm and 3 mm bands with the Nobeyama 45 m telescope at the Nobeyama Radio Observatory (NRO) 1 in May and December, 2014.The observed position is : (α J2000 , δ J2000 ) = (6 h 41 m 12 s .3, +09 • 29 ′ 11 ′′ .9). Eight frequency settings were observed to cover the frequency range from 67.5 to 116.0 GHz. The sideband separating (2SB) mixer receivers T70H/V and TZ1H/V (Nakajima et al. 2013) were used as frontends with the typical system noise temperature of 140 -380 K. The image rejection ratios were measured just before each observation session by applying artificial signals, and were assured to be better than 10 dB. The beam size ranged from 22 ′′ to 15 ′′ .The backends were 16 SMA45 autocorrelators whose band width and frequency resolution each are 1600 MHz and 0.5 MHz, respectively. The frequency resolution corresponds to a velocity resolution of 1.7 km s −1 at 90 GHz. This resolution is enough for resolving spectral line profiles observed in NGC 2264 CMM3 (∼ 3 km s −1 ). The position-switching method was employed with the off-position at (∆α, ∆δ) = (-25 ′ , -25 ′ ). The telescope pointing was checked every hour by observing the SiO maser source SY-Mon. Pointing accuracy was confirmed to be better than 5 ′′ . Intensity scale was calibrated to the antenna temperature (T * a ) scale by using the chopper-wheel method, and its accuracy is estimated to be 20 %. The antenna temperature was converted to the main-beam brightness temperature (T mb ) by T mb = T ...

NGC 2264-C is a high-mass protocluster where several star-formation events are known to have occurred. To investigate whether past protostellar activity has left a chemical imprint in this region, we mapped it in SiO(J = 2 − 1), a shock tracer, and several other molecular lines with the Nobeyama 45 m telescope. Our observations show the presence of a complex network of protostellar outflows. The strongest SiO emission lies beyond a radius of ∼ 0.1 pc with respect to the center of the clump, and is characterized by broad (> 10 km s −1 ) lines and abundances of ∼ 1.4 × 10 −8 with respect to H 2 . Interestingly, SiO appears relatively depleted (χ SiO ∼ 4 × 10 −9 ) within this radius, despite it being affected by molecular outflow activity. We attribute this to fast condensation of SiO back onto dust grains and/or rapid gas-phase destruction of SiO, favored by the high density present in this area (> 10 6 cm −3 ). Finally, we identify a peripheral, narrow-line (∼ 2 km s −1 ) component, where SiO has an abundance of a few times 10 −11 . After considering different options, we conclude that this weak emission may be tracing protostellar shocks from the star formation episode that preceded the current one, which have decelerated over time and eventually resulted in SiO being largely depleted/destroyed. Alternatively, a population of unresolved low-mass protostars may be responsible for the narrow SiO emission. Highangular resolution observations are necessary to distinguish between these two possibilities and thus understand the role of SiO as a chemical tracer of past star-formation episodes in massive protoclusters.

No abstract

No abstract

We have developed waveguide-type low-noise superconducting hot-electron bolometer (HEB) mixers for astronomical observations in the 1.3–1.5 THz region by using a relatively thick NbTiN superconducting film (10.8 nm). We have achieved a receiver noise temperature of 490 K (DSB: double side band) at 1.475 THz. This noise temperature corresponds to seven times the quantum noise. According to gain bandwidth measurements, the contribution of diffusion cooling is found to be responsible for such a good noise performance.