Non-thermal Continuum toward Sgrb2(n-lmh)

An analysis of continuum antenna temperatures observed in the Green Bank Telescope (GBT) spectrometer bandpasses is presented for observations toward SgrB2(N-LMH). Since 2004, we have identified four new prebiotic molecules toward this source by means of rotational transitions between low energy levels; concurrently, we have observed significant continuum in GBT spectrometer bandpasses centered at 85 different frequencies in the range of 1 to 48 GHz. The continuum heavily influences the molecular spectral features since we have observed far more absorption lines than emission lines for each of these new molecular species. Hence, it is important to understand the nature, distribution, and intensity of the underlying continuum in the GBT bandpasses for the purposes of radiative transfer, i.e., the means by which reliable molecular abundances are estimated. We find that the GBT spectrometer bandpass continuum is consistent with optically-thin, non-thermal (synchrotron) emission with a flux density spectral index of -0.7 and a Gaussian source size of ∼143 at 1 GHz that decreases with increasing frequency as ν. Some support for this model is provided by high frequency Very Large Array (VLA) observations of SgrB2. Subject headings: radiation mechanisms: nonthermal – ISM: HII regions ISM: individual (Sagittarius B2(N-LMH)) ISM: radio continuum: interstellar The North source in SgrB2, i.e. SgrB2(N), is a giant star-forming region that lies along the galactic equator near the center of our Galaxy. When searching for new interstellar molecules in SgrB2, the pointing position SgrB2(N-LMH) has produced excellent results. There is another strong molecular source 45 to the south of this pointing position known as Main, i.e. SgrB2(M), that can influence molecular detections toward SgrB2(N-LMH) if NASA Goddard Space Flight Center, Computational and Information Sciences and Technology Office, Code 606, Greenbelt, MD 20771 National Radio Astronomy Observatory, 520 Edgemont Road, Charlottesville, VA, 22903-2475 Optical Technology Division, National Institute of Standards and Technology, Gaithersburg, MD 20899