Person: Keto, Eric
Loading...
Email Address
AA Acceptance Date
Birth Date
Research Projects
Organizational Units
Job Title
Last Name
Keto
First Name
Eric
Name
Keto, Eric
3 results
Search Results
Now showing 1 - 3 of 3
Publication Submillimeter Array 440 μm/690 GHz Line and Continuum Observations of Orion KL(IOP Publishing, 2006) Beuther, H.; Zhang, Qizhou; Reid, Mark; Hunter, T. R.; Gurwell, Mark; Wilner, David; Zhao, Jun-Hui; Shinnaga, H.; Keto, Eric; Ho, P. T. P.; Moran, James; Liu, S.‐Y.Submillimeter Array observations of Orion-KL at ∼ 1′′ resolution in the 440 µm/690 GHz band reveal new insights about the continuum and line emission of the region. The 440 µm continuum flux density measurement from source I allows us to differentiate among the various proposed physical models: Source I can be well modeled by a “normal” protostellar SED consisting of a proton-electron free-free emission component at low frequencies and a strong dust component in the submillimeter bands. Furthermore, we find that the protostellar object SMA1 is clearly distinct from the hot core. The non-detection of SMA1 at cm and infrared wavelengths suggests that it may be one of the youngest sources in the entire Orion-KL region. The molecular line maps show emission mainly from the sources I, SMA1 and the hot core peak position. An analysis of the CH 3CN(37 K − 36 K) K-ladder ( K = 0...3) indicates a warm gas component of the order 600 ± 200K. In addition, we detect a large fraction ( ∼ 58%) of unidentified lines and discuss the difficulties of line identifications at these frequencies.Publication Line Imaging of Orion KL at 865 μm with the Submillimeter Array(IOP Publishing, 2005) Beuther, H.; Zhang, Qizhou; Greenhill, Lincoln; Reid, Mark; Wilner, David; Keto, Eric; Shinnaga, H.; Ho, P. T. P.; Moran, James; Liu, S.‐Y.; Chang, Chih-WeiWe present the first submm (865 µm) imaging spectral line survey at one arcsecond resolution conducted with the Submillimeter Array toward Orion-KL. Within the two × two GHz bandpasses (lower and upper sidebands, 337.2–339.2GHz and 347.2–349.2GHz), we find about 145 spectral lines from 13 species, 6 isotopologues, and 5 vibrational excited states. Most nitrogen-bearing molecules are strong toward the hot core, whereas the oxygen-bearing molecules peak toward the south-west in the so-called compact ridge. Imaging of spectral lines is shown to be an additional tool to improve the identifications of molecular lines. Arcsecond spatial resolution allows us to distinguish the molecular line emission of the sources I and n from that of the hot core. The only molecular species detected strongly toward source I is SiO, delineating mainly the collimated north-east south-west low-velocity outflow. The two positions close to source I, which have previously been reported to show maser emission in the v=0 28SiO(1–0) and (2–1) lines, show no detectable maser emission in the v=0 28SiO(8–7) line at our spatial resolution. SiO is weak toward source n, and thus source n may not currently be driving a molecular outflow. CH 3OH is the molecule with the highest number of identified lines (46) in this spectral window. This “line forest” allows us to estimate temperatures in the region, and we find temperatures between 50 and 350 K, with the peak temperatures occurring toward the hot core. The detection of strong vibrational excited line emission from the submm continuum peak SMA1 supports the interpretation that the source SMA1 is likely of protostellar nature.Publication Subarcsecond Submillimeter Continuum Observations of Orion KL(IOP Publishing, 2004) Beuther, H.; Zhang, Qizhou; Greenhill, Lincoln; Reid, Mark; Wilner, David; Keto, Eric; Marrone, D.; Ho, P. T. P.; Moran, James; Rao, R.; Shinnaga, H.; Liu, S.-Y.We present the first 865 µm continuum image with sub-arcsecond resolution obtained with the Submillimeter Array. These data resolve the Orion-KL region into the hot core, the nearby radio source I, the sub-mm counterpart to the infrared source n (radio source L), and new sub-mm continuum sources. The radio to submillimeter emission from source I may be modeled as either the result of proton-electron free-free emission that is optically thick to ∼ 100 GHz plus dust emission that accounts for the majority of the submillimeter flux, or H− free-free emission that gives rise to a power-law spectrum with power-law index of ∼ 1.6. The latter model would indicate similar physical conditions as found in the inner circumstellar environment of Mira variable stars. Future sub-arcsecond observations at shorter sub-mm wavelengths should easily discriminate between these two possibilities. The sub-mm continuum emission toward source n can be interpreted in the framework of emission from an accretion disk.