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J/ApJ/604/717       Polarization in OMC 1/4                  (Houde+, 2004)

Tracing the magnetic field in Orion A. Houde M., Dowell C.D., Hildebrand R.H., Dotson J.L., Vaillancourt J.E., Phillips T.G., Peng R., Bastien P. <Astrophys. J., 604, 717-740 (2004)> =2004ApJ...604..717H
ADC_Keywords: Molecular clouds ; Radio lines ; Polarization Keywords: ISM: clouds - ISM: individual (Orion) - ISM: magnetic fields - polarization - radio lines: ISM Abstract: We use extensive 350µm polarimetry and continuum maps obtained with the Hertz polarimeter and SHARC II (Submillimeter High Angular Resolution Camera II) along with HCN and HCO+ spectroscopic data to trace the orientation of the magnetic field in the Orion A star-forming region. Using the polarimetry data, we find that the direction of the projection of the magnetic field in the plane of the sky relative to the orientation of the integral-shaped filament varies considerably as one moves from north to south. By combining the polarimetry and spectroscopic data, we were able to measure a set of average values for the inclination angle of the magnetic field relative to the line of sight. We also present polarimetry data for the OMC-4 region located some 13' south of OMC-1. Description: The core of the data presented in this paper comes from extensive 350µm polarimetry maps obtained with the Hertz polarimeter during numerous nights of observations at the Caltech Submillimeter Observatory. In all, seven different regions of the OMC were studied. They are, from north to south: (1) IRAS 05327-0457, observed on 2002 February 17-18; (2) OMC-3 MMS 16, observed on 1997 September 19, 1998 February 15, 1999 January 27, and 2002 February 18; (3) OMC-3 MMS 89, observed on 2002 February 18; (4) the neighborhood of OMC-2 FIR 34, observed on 1997 September 19, 1998 February 15, and 1999 January 27; (5) the neighborhood of OMC-2 FIR 6, observed on 2002 February 18; (6) OMC-1, observed on numerous nights from 1998 February to 2002 February; and finally (8) OMC-4, observed on 2001 April 16 and 2002 February 18. Although the Hertz data provide both polarimetry and continuum maps, we use a SHARC II map for illustrations of the 350µm continuum. The SHARC II data were obtained on three separate nights: 2002 November 24, 2003 March 1, and 2003 April 16. Objects: --------------------------------------------------------------- RA (2000) DE Designation(s) (File) --------------------------------------------------------------- 05 35 14.0 -05 22 24 OMC-1 = OMC 1 (table2.dat) 05 35 27.0 -05 10 06 OMC-2 = OMC 2 (table3.dat) 05 45 15.0 -05 00 18 OMC-3 = OMC 3 (table4.dat) 05 36 06.2 -05 35 40 OMC-4 = OMC 4 (table5.dat) 05 35 14.4 -04 55 45 IRAS 05327-0457 = [TUK93] 1 (table4.dat) --------------------------------------------------------------- File Summary:
FileName Lrecl Records Explanations
ReadMe 80 . This file table2.dat 43 470 OMC-1, 350 micron Results table3.dat 43 52 OMC-2, 350 micron Results table4.dat 43 85 OMC-3 and IRAS 05327-0457, 350 micron Results table5.dat 43 19 OMC-4, 350 micron Results
See also: J/AJ/125/1537 : QUIRC Chandra sources in OMC 2/3 (Tsujimoto+, 2003) J/ApJ/566/974 : CHANDRA obs. of YSOs in OMC-2 and OMC-3 (Tsujimoto+, 2002) Byte-by-byte Description of file: table?.dat
Bytes Format Units Label Explanations
1- 5 F5.2 arcmin oRA Offset in Right Ascension (1) 7- 12 F6.2 arcmin oDE Offset in Declination (1) 14- 18 F5.2 % Pol Polarization level 20- 23 F4.2 % e_Pol The 1σ error in Pol 25- 29 F5.1 deg PA Position angle (2) 31- 35 F5.1 deg e_PA The 1σ error in PA 37- 42 F6.1 Jy Flux Flux of the 20 arcsecond beam
Note (1): Offset from RA: 5:32:50, DE: -5:15:00 (B1950.0). Sorted in DE first. Note (2): Position angle of E-vector in degrees east from north.
History: From electronic version of the journal
(End) Greg Schwarz [AAS], Patricia Vannier [CDS] 07-May-2004
The document above follows the rules of the Standard Description for Astronomical Catalogues.From this documentation it is possible to generate f77 program to load files into arrays or line by line

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