Biomedical subjects

P Schilke

Publications and source records attributed to P Schilke.

3 recordsLinked to original sources

PubMed2000

A Submillimeter HCN Laser in IRC +10216.

We report the detection of a strong submillimeter-wavelength HCN laser line at a frequency near 805 GHz toward the carbon star IRC +10216. This line, the J=9-8 rotational transition within the (0400) vibrationally excited state, is one of a series of HCN laser lines that were first detected in the laboratory in the early days of laser spectroscopy. Since its lower energy level is 4200 K above the ground state, the laser emission must arise from the innermost part of IRC +10216's circumstellar envelope. To better characterize this environment, we observed other, thermally emitting, vibrationally excited HCN lines and found that they, like the laser line, arise in a region of temperature approximately 1000 K that is located within the dust formation radius; this conclusion is supported by the line width of the laser. The (0400), J=9-8 laser might be chemically pumped and may be the only known laser (or maser) that is excited both in the laboratory and in space by a similar mechanism.

Journal Article↗

PubMed1997

33SO2: Interstellar Identification and Laboratory Measurements

The rotational spectrum of 33S isotopically substituted sulfur dioxide, 33SO2, has been measured up to nearly 1 THz. The combined analysis of these new data together with the published line frequencies resulted in refined molecular constants, such as the rotational (A = 59856.4723(62) MHz, B = 10318.3012(15) MHz, C = 8780.1363(15) MHz) and centrifugal distortion constants which yielded precise frequency predictions. The carrier of six previously unidentified interstellar lines in the Caltech molecular line survey in the 325-360 GHz band could be assigned to 33SO2. Copyright 1997 Academic Press. Copyright 1997Academic Press

Journal Article↗

PubMed1997

A line survey of Orion KL from 325 to 360 GHz.

We present a high-sensitivity spectral line survey of the high-mass star-forming region Orion KL in the 325-360 GHz frequency band. The survey was conducted at the Caltech Submillimeter Observatory on Mauna Kea, Hawaii. The sensitivity achieved is typically 0.1-0.5 K and is limited mostly by the sideband separation method utilized. We find 717 resolvable features consisting of 1004 lines, among which 60 are unidentified. The identified lines are due to 34 species and various isotopomers. Most of the unidentified lines are weak, and many of them most likely due to isotopomers or vibrationally or torsionally excited states of known species with unknown line frequencies, but a few reach the 2-5 K level. No new species have been identified, but we were able to strengthen evidence for the identification of ethanol in Orion and found the first nitrogen sulfide line in this source. The molecule dominating the integrated line emission is S02, which emits twice the intensity of CO, followed by SO, which is only slightly stronger than CO. In contrast, the largest number of lines is emitted from heavy organic rotors like HCOOCH3, CH3CH2CN, and CH3OCH3, but their contribution to the total flux is unimportant. CH3OH is also very prominent, both in the number of lines and in integrated flux. An interesting detail of this survey is the first detection of vibrationally excited HCN in the v2 = 2 state, 2000 K above ground. Clearly this is a glimpse into the very inner part of the Orion hot core.

Astronomy↗