Detection, Identification, and Correlation of Complex Organic Molecules in 32 Interstellar Clouds Using

Submm Survey Observations

Nadine Wehres, Shiya Wang, Mary Radhuber, Jim Sanders, Jay Kroll, Jake Laas, Luyao Zou, Brian Hays, Trevor Cross, Susanna Widicus Weaver

Department of Chemistry, Emory University, Atlanta, GA 30322

Darek LisDivision of Physics, Mathematics, and Astronomy, California Institute of Technology, Pasadena, CA 91125

Eric HerbstDepartment of Chemistry, University of Virginia, Charlottesville, VA

Molecular Line Surveys using Broadband Heterodyne Receivers

Probe multiple transitions of many molecules simultaneously in a broad energy range

Detailed picture of the physical and chemical conditions (T, r)

Insight into ongoing chemistry, including reaction networks

Input and proof of concept for astrochemical models

Deeper understanding of the formation, destruction, and reaction pathways of these complex species

CSO and Herschel Caltech Submillimeter Observatory

Zrx and broadband sidecab RxCoverage: 219,300 – 267,100 MHz

Resolution: 1 MHz

Herschel Space ObservatoryHeterodyne Instrument for the Far-IR (HIFI)Band 2: 647,700 – 676,200 MHzBand 5: 1,139,700 – 1,168,000 MHzResolution : 134 kHz – 1 MHz

ESA / AOES Medialab HST, NASA/ ESA/ STScI

32 Sources in Star Forming Regions

Shocks and outflows, Hot Cores/Hot Corinos, Quiescent Clouds, ambient/cold clouds, HII

Integration to ~ 20 mK average NGC1333 IRAS 2A G10.47+0.03 G75.78+0.34 NGC6334-29 G34.30+0.20

NGC1333 IRAS 2B W51 G45.47+0.05 NGC6334-38 B1-b

NGC1333 IRAS 4A G12.21-0.10 DR21(OH) NGC6334-43 GCM +0.693-0.027

NGC1333 IRAS 4B G19.61-0.23 G24.33+0.11 NGC6334-IN

NGC2264 W75N G29.96-0.02 Orion KL

NGC7538 G31.41+0.31 G12.91-0.26 L1157

SgrB2N-LMH W3(OH) HH80

G24.78+0.08 L1448MM

Initial Analysis: 12 Molecular Targets Complex organic molecules (COMs) with specific functional groups that trace

formation pathways and physical conditions

Products of gas phase and grain surface chemistry

Initial constraints of associated formation pathways can be determined through these molecules

CSO Line Surveys

Herschel HIFI Line Surveys

ESA / AOES Medialab HST, NASA/ ESA/ STScI

GOBASIC – Global Optimization and Analysis Software for Interstellar Chemistry

Simulation for DR21OH created with GOBASIC in the MATLAB program suite

GOBASIC, Radhuber et al. A&A in revision

Input: JPL/CDMS catalog filesOutput: Column densities, Trot,Spectra are simulated under the

assumption of LTE

Correlation Diagram of Methyl Cyanide vs Methanol

Orion

*NGC6334_I(N)

* Brightest known source of ammonia emission in the sky(Forster et al. 1987 )

Correlation Diagram of Ethyl Cyanide vs Methanol

Correlation Diagram of Sulfur Dioxide vs Methanol

NGC6334_I(N)

Correlation Diagram of Methyl Formate vs Methanol

Correlation between Dimethyl Ether vs Methanol

NGC6334_I(N)

Work in Progress: CARMA Maps

Friedel and Widicus Weaver, ApJS., 201, 17, 2012.

CARMA maps of molecular emission contours overlaid on a Methanol temperature map of Orion-KL

Methyl Formate Ethyl Cyanide

Conclusions

Surveys of 32 star forming regions have been obtained and deconvolution of the double sideband spectra has been performed using CLASS

Initial analysis focuses on 12 complex organic species

Analysis performed using the GOBASIC program suite assuming LTE

Additional CARMA maps will give spatial information for molecules

Correlation of column densities may indicate related chemistry in the formation and destruction of molecules.

AcknowledgementsThe Widicus Weaver Group:Bridget DePrince, Brian Hays, Jake Laas, Mary Radhuber, Jim Sanders, AJ MeskoTrevor Cross, Luyao Zou