Spectroscopy with TianMa 65m and also FAST Junzhi Wang SHAO On behalf of the Shanghai 65m RT Team

Outline Introduction of TianMa telescope Capability of radio spectroscopy with TianMa Our ongoing observational projects with TianMa Spectroscopy with FAST early science

Shanghai 65m Radio Telescope 65-m in diameter, fully steerable radio telescope Active surface system installed Covering 1 – 50 GHz with 8 bands L(1.6GHz), S/X(2.3/8.4GHz) C(5GHz), Ku(15GHz), K(22GHz) Ka(30GHz), Q(43GHz) General-purpose (radio astronomy, single-dish, VLBI, geodynamics) Funding Agencies: Chinese Academy of Sciences (CAS) Shanghai Municipality Chinese Lunar Exploration Project Cost ≈ 32M USD

Project Timeline 2008：funded; contract to CETC54 for the antenna construction 2009: complete design (international review panel); start manufacturing; foundation laying ceremony on December 29 2010-11: site construction started on March 19, 2010; foundation completed; antenna construction (wheel-on-track, BUS, alidade, panels, …); active surface system (contract, design, fabrication, installation of actuators) 2012-13: L/S/X and C band Rxs in place; first light on October 26, 2012 & inauguration 2 days later; start commissioning; got named (天马); participation in the Chinese Lunar Mission (ChangE); DIBAS installed & tested 2014-16: on-site system testing; science observations at L/S/C/X bands; active surface tested; Ku/K/Ka/Q band commissioning; project accomplished

Telescope Specs Frequency coverage: 1 ~ 50 GHz Primary reflector adjustable with 1104 actuators Surface accuracy (nominal)： 0.53mm RMS (without active surface) 0.29mm RMS (with active surface) Aperture Efficiency： L/S/C > 60%, X > 55%, Ku > 40%, K > 20% Ka > 50%, Q > 45% (with active surface) Pointing accuracy： 6 arcsec (wind < 4m/s) [c.f. beam ~ 22 arcsec @43 GHz] 10 arcsec (wind < 10m/s) 30 arcsec (wind < 20m/s) Elevation limits: 5~90 degree Slew rates: 0.5 degree/s (azimuth), 0.3 degree/s (elevation) 5

Receiver specs Band "L" "S" "C" "X" "Ku" "K" "Ka" "Q" Wavelength (cm) 21/18 13 6/5 3.6 2/2.5 1.3 0.9 0.7 Freq range (GHz) 1.25-1.75 2.2-2.4 4-8 8.2-9.0 12-18 18.0-26.5 30-34 35-50 Freq low (GHz) 1.25 2.2 4 8.2 12 18 30 35 Freq high (GHz) 1.75 2.4 8 9 26.5 34 50 BW (GHz) 0.5 0.2 0.8 6 8.5 15 BW/CF (%) 33 67 40 38 Freq high/low 1.4 1.1 2.0 1.5 FWHP@CF (") 647.4 422.2 161.8 112.9 64.7 43.6 30.3 22.8 T(Sky) (K) 10 25 26 T(Rx) (K) 14 21 22 T(Sys) (K) 32 27 60 43 66 Efficiency 55% 60% 50% DPFU (K/Jy) 0.66 0.72 0.60 SEFD (Jy) 39 46 48 41 100 72 110 Sensitivity (mJy) 128MHz BW/10min 0.142 0.165 0.110 0.175 0.147 0.360 0.258 0.396 full BW/10min 0.072 0.132 0.020 0.070 0.022 0.044 0.046 0.037 Feed Type Compact Conical Polarization Lin & Circ Dual Circ Refrigerator 1020 350 Structure Single Pixel Dual Band Dual Pixels Status Installed May 2013 Installed Dec 2012 Installed Sep 2014 Installed Mar 2016 Installed Dec 2014

DIBAS: DIgital BAckend System An updated version of the NRAO-VEGAS (Versatile GBT Astronomical Spectrometer), customized with the addition of NRAO-GUPPI (Green Bank Ultimate Pulsar Processing Instrument) Support two types of observing modes Spectral line modes: support 29 modes, including wideband up to 16,384 channels, narrowband up to 524,288 channels and, sub-band modes (higher spectral-resolution over multiple narrow bands (sub-bands) within the sampled bandwidth) Pulsar modes: support the incoherent/coherent search and pulsar timing modes. 7

DIBAS Spectrometer Specs 8

DIBAS Spectrometer Specs

DIBAS Spectrometer Specs(cont’d)

K-band specifications Requirement Frequency Band 18-26.5 GHz (complete K-Band coverage) TRX (each beam, not including sky) < 25 K (75% of band), < 36 K (entire band) Number of beams 2 (expandable up to 3) Polarization dual, circular (axial ratio <= 1 dB) Polarization Isolation >25 dB Pixel-Pixel Isolation >30 dB Aperture Efficiency >55%, any pixel Sideband (image) rejection > 25 dB 1st fixed Local Oscillator frequency 16 GHz Instantaneous RF Bandwidth 8.5 GHz ( 2-10.5 GHz) Headroom > 30 dB (to 1 dB compression point) 11

EAVWS2010, Kagoshima, Japan, 22-24 April 2010 RFI Environment Two site surveys (2008 May and 2009 October) are consistent in that，most RFIs appear at the outside of the designed bands, and at C-band and above RFI is not a problem. Some RFIs at L-band!!! L 1.25~1.75GHz S 2.15~2.45GHz C 4.5~7GHz X 8~9GHz EAVWS2010, Kagoshima, Japan, 22-24 April 2010 12

RFI @ SH65m site

RFI protection

site meteorology - PWV Precipitable Water Vapor (PWV) Good in Autumn/winter !

site meteorology - optical depth (τ) 22GHz： about 1/3 days with less than 0.1 optical depth 43GHz： about 1/4days with less than 0.1 optical depth

Capability of Spectral line high sensitivity, wide frequency coverage Suitable for spectral line observations. Standard PS mode and OTF mode can be used now. Data from 2IFs (~1GHz) obtained Simultaneously Discovery of new lines (masers or thermal) Search for some important line emissions, such as high-z CO (bw=4MHz, T=20hr, sigma=0.2 mJy@22GHz, or, 0.9mJy @ 43 GHz) Multiple-line observation towards SFRs Deep K-band Galactic Plane Survey 17

Spectral line emission in ~10 - 50 GHz K 18

Molecular lines at cm-band Menten 2004 19

C-band（4-8 GHz） > 1K：6.7 GHz CH3OH，4.765 & 6.035 GHz OH maser, CH2CNH (-1.3 K, Sgr B2, Lovas et al. 2006, no follow-up) >0.1K：H2CO absorption，NH2CHO (0.3 K, Sgr B2, Rub et al. 1971) > 0.01 K: HC5N, HC7N, HC9N… RRLs Ku (12-18.5 GHz) band is another important band for TianMa 20

NSFC Major project Studying Star formation and ISM with TianMa Chief Scientist : Prof. Zhiqiang Shen From 2016Jan to 2020Dec Group 1: Star formation in the Milky Way Group 2: ISM properties and star formation history in the Milky Way Group 3: Dense gas and Star formation in nearby galaxies Group 4: Mega-masers, starburst and AGN 21

Group 1:Star formation in the Milky Way 6.7 GHz CH3OH maser survey toward candidates of massive star forming regions selected with WISE color (on-going, almost done) RRL survey toward massive star forming regions selected both with WISE YSO candidates and strong radio continuum emission (on-going) NH3 mapping observations toward massive star forming regions based on CH3OH and RRL survey (will start from the end of this year) Further high resolution observational studies with (sub-)millimeter observations for some of the sources 22

Work Progress  

Group 2:ISM and Star formation history in the Milky Way Observing lines of long carbon chain molecules, such as HC5N, HC7N in Galactic molecular clouds Determining electron properties (density, temperatures, etc.) with the observations of multiple transition RRLs Isotopic abundances of 12C/13C, 14N/15N, 33S/34S with different distances to the Galactic center (DGC): star formation history? 24

HC5N, HC7N, HC9N,C3S, C6H, C8H and isotopic line of HC3N were detected Lines of long carbon chain molecules in Serpens South 1a detected with TianMa Left：HC3N 2-1 and its 13C isotopic lines; Right: Comparison between Serpens South 1a and TMC-1、Lupus-1A。 HC5N, HC7N, HC9N,C3S, C6H, C8H and isotopic line of HC3N were detected Li, Juan et al., , 2016, ApJ, 824, 136 “TMRT Observation of carbon-chain Molecules in Serpens South 1A” as the first refereed paper of spectroscopy observation with TianMa

Li Juan et al. in preparation

Group 3:Dense gas and star formation in nearby galaxies Dense gas tracers and star formation law: what can we do with TianMa? CS 1-0, HC3N 5-4 & 2-1 in nearby galaxies with TianMa Optically thin lines of dense gas tracers in galaxies: isotopic lines, such as 13CS 1-0 and C34S 1-0 Mapping massive star forming regions with the same lines as that for galaxies: obtain the conversion factor of luminosity to dense gas mass 27

Detected dense gas tracers Nearby galaxy M66 HC3N 2-1 Will test CS 1-0 in coming months using Q band receiver 28

Group 4:Mega-maser, starburst and AGN Searching for new H2O mega-maser sources Searching for CH3OH mega-masers Radio continuum properties of H2O and OH mega-maser host galaxies VLBI imaging for H2O and OH mega-masers 29

Five-hundred-metre Aperture Spherical Telescope (FAST) Diameter: 500m Frequency range:70MHz-3GHz, early science (270MHz-1620MHz) Pulsar, spectroscopy, VLBI 2016 Sep 25 30

Spectroscopy with FAST early science Capabilities: limited tracking time flux calibration is not perfect weak RFI is not well known bandpass stability is not perfect Good sensitivity Better choices: Known frequency and red-shift, relatively strong, but still weak lines hard for long integration time difficult for unknown frequency lines Largest OH MM sample highest red-shifted OH MM (?) OH mega-maser survey Long carbon chain lines (HC2n+1N) in low mass star forming regions Largest molecule (?) 31

Thanks for your attention !