Molecule Search Summing Lines Demo Detection of Isotopomers
- Slides: 18
Molecule Search: Summing Lines Demo: Detection of Isotopomers of HC 5 N In 39 -48 GHz GBT Survey of TMC Glen Langston (NSF) + Many Students S
Why Molecules? - Precursors of Life • Molecular Chemistry is Dynamic • Diagnostic clock of star formation • Cloud temperature Image from Tielens (2013), Reviews of Modern Physics, vol. 85, page 1021
What Telescope? - GBT a. k. a. Robert C. Byrd Green Bank Telescope 100 m Diameter 0. 3 to 90 GHz Multi-band Spectrometer Radio Quiet Zone
What Molecules? - Carbon Chains Molecules found by Hollis, Jewell, Lovas, Remijan, Mollendal, 2004 Ap. J. Let. 610, L 21 Lovas, Remijan, Hollis, Jewell, Snyder (2006) Ap. J. Let. 637, L 37
Confirm Molecules? - Select Carbon Chains
Where? - Taurus Molecular Cloud (TMC) Taurus Region Rich in Molecules Long Carbon Chains found in TMC and several regions CO https: //science. nrao. edu/science/Decadal%20 Survey/tech/langston_chemistrymap_TEC_RMS. pdf CO image from Goldsmith, P. F. , Heyer, M. H. , Narayanan, G. , Snell, R. L. , Li, D. , & Brunt, C. , 2008
What Data? - GBT 39 -48 GHz TMC Survey Soon to be in Ap. J. Supp. , with all calibrated data online Spectral Resolution 0. 04 km/sec Sensitivity 0. 06 K RMS (1 Hour obs. )
Where? - TMC Cyanopolyyene Peak HC 5 N H CCCCC N Averaging Lines in velocity to increase SNR
What Demo? - Isotopomers of H 13 CC 4 N All Lines See: Langston, Turner (2007), Ap. J. 658, 455. Average Line
What Demo? - Isotopomers of HC 13 CC 3 N All Lines Average line
What Demo? - Isotopomers of HC 213 CC 2 N All Lines Average line
What Demo? - Isotopomers of HC 313 CCN All Lines Average line
What Demo? - Isotopomers of HC 413 CN All Lines Average line
What Demo? - Average All Isotopomers HC 5 N 3 HC 5 N lines in this frequency range Peak 3. 334 +/- 0. 005 K (TB) RMS 0. 011 K 5 x 3 HC 5 N Isotopomer lines Peak 0. 047 +/- 0. 003 K (TB) RMS 0. 007 K
What Demo! - 12 C/13 C = 71. 5 +/- 4. 5
New Confirmation? - H 2 C 3 HCN 14 Strongest Lines in frequency range. No detection of any individual line. Weighted average shows clear 10 sigma detection.
New Confirmation! - H 2 C 3 HCN 0. 057 +/- 0. 005 Confirmation.
New Detection? - Keep Posted Thanks! Great Summer Students H? C? N NRAO and GBT Staff Astrochemists for Lines and Models. Cologne Database of Molecular Spectroscopy THE COLOGNE DATABASE FOR MOLECULAR SPECTROSCOPY, CDMS by H. S. P. Müller, S. Thorwirth, D. A. Roth, and G. Winnewisser; Astron. Astrophys. 370 (2001) L 49 – L 52. H. S. P. Müller, F. Schlöder, J. Stutzki, and G. Winnewisser, THE COLOGNE DATABASE FOR MOLECULAR SPECTROSCOPY, CDMS: A USEFUL TOOL FOR ASTRONOMERS AND SPECTROSCOPISTS, J. Mol. Struct. 742, 215– 227 (2005).