TIME MONITORING OBSERVATIONS OF SiO J = 2 - 1 AND J = 3 - 2 LINES TOWARD ORION KL

• Published in: The Astronomical journal 2010-01, Vol.139 (1)
• Main Authors: Cho, Se-Hyung, Kim, Hyun-Goo, Chung, Hyun-Soo, Roh, Duk-Gyoo, Kim, Hyo-Ryung, Yun, Youngjoo
• Format: Article
• Language: English
• Subjects: ASTRONOMY; ASTROPHYSICS, COSMOLOGY AND ASTRONOMY; GENERAL AND MISCELLANEOUS//MATHEMATICS, COMPUTING, AND INFORMATION SCIENCE; MASERS; MONITORING; RADIO TELESCOPES; SILICON OXIDES; STARS
• ISSN: 1538-3881; 1538-3881
• DOI: 10.1088/0004-6256/139/1/302;COUNTRYOFINPUT:INTERNATIONALATOMICENERGYAGENCY(IAEA)

We have carried out time monitoring observations of the {sup 28}SiO v = 0, 1, 2, J = 2 - 1, {sup 28}SiO v = 0, 1, 2, J = 3 - 2, and {sup 29}SiO v = 0, J = 3 - 2 transitions in Orion KL with the 14 m radio telescope at Taeduk Radio Astronomy Observatory. The pair of J = 2 - 1 and J = 3 - 2 transitions was simultaneously observed from 1999 January to 2001 March. Each transition shows different characteristics. Both the v = 1, J = 2 - 1, and J = 3 - 2 masers show a relatively stable double-peaked profile and little variation in intensity. The {sup 28}SiO v = 2, J = 3 - 2 maser presents the most active intensity variations including a disappearance on 2000 February 17 and 2001 February 16. The v = 2, J = 3 - 2 maser may trace the closest region to the central young stellar object and results in the strongest variations of intensity and line profile. The v = 2, J = 2 - 1 maser was not detected in the monitoring. The {sup 28}SiO v = 0, J = 3 - 2 lines showed a large variation of peak intensity compared with {sup 28}SiO v = 0, J = 2 - 1 that might be due to partial masing. The different observational results of {sup 28}SiO v = 0, 1, J = 2 - 1, {sup 28}SiO v = 0, 1, 2, J = 3 - 2, and {sup 29}SiO v = 0, J = 3 - 2 transitions might reflect that individual transitions trace different portions of gas.