J/ApJ/708/758 Polarimetry of HH1-2 region (Kwon+, 2010)
Magnetic field structure of the HH 1-2 region: near-infrared polarimetry of point-like sources. Kwon J., Choi M., Pak S., Kandori R., Tamura M., Nagata T., Sato S. <Astrophys. J., 708, 758-769 (2010)> =2010ApJ...708..758K
ADC_Keywords: Polarization ; Photometry, infrared ; YSOs ; Molecular clouds Keywords: infrared: stars - ISM: individual (HH 1-2) - ISM: structure - polarization - stars: formation Abstract: The HH 1-2 region in the L1641 molecular cloud was observed in the near-infrared (IR) J, H, and Ks bands, and imaging polarimetry was performed. Seventy-six point-like sources were detected in all three bands. The near-IR polarizations of these sources seem to be caused mostly by the dichroic extinction. Using a color-color diagram, reddened sources with little IR excess were selected to trace the magnetic field structure of the molecular cloud. The mean polarization position angle of these sources is about 111°, which is interpreted as the projected direction of the magnetic field in the observed region of the cloud. The distribution of the polarization angle has a dispersion of about 11°, which is smaller than what was measured in previous studies. This small dispersion gives a rough estimate of the strength of the magnetic field to be about 130uG and suggests that the global magnetic field in this region is quite regular and straight. In contrast, the outflows driven by young stellar objects in this region seem to have no preferred orientation. This discrepancy suggests that the magnetic field in the L1641 molecular cloud does not dictate the orientation of the protostars forming inside. Description: The observations toward the HH 1-2 region were carried out using the SIRPOL imaging polarimeter on the Infrared Survey Facility (IRSF) 1.4m telescope at the South African Astronomical Observatory. The observations were made on the night of 2008 January 9. File Summary:
FileName Lrecl Records Explanations
ReadMe 80 . This file table1.dat 45 76 Photometry of point-like sources in the HH 1-2 field table2.dat 69 76 Polarimetry of point-like sources in the HH 1-2 field
See also: II/246 : 2MASS All-Sky Catalog of Point Sources (Cutri+ 2003) J/A+A/504/461 : YSOs in L1630N and L1641 (Fang+, 2009) Byte-by-byte Description of file: table1.dat
Bytes Format Units Label Explanations
1- 2 I2 --- Name Source name (<[KCP2010] NN> for Simbad) 4 I1 h RAh Hour of right ascension (J2000) (1) 6- 7 I2 min RAm Minute of right ascension (J2000) 9- 13 F5.2 s RAs Second of right ascension (J2000) 15 A1 --- DE- Sign of declination (J2000) (1) 16 I1 deg DEd Degree of declination (J2000) (1) 18- 19 I2 arcmin DEm Arcminute of declination (J2000) 21- 24 F4.1 arcsec DEs Arcsecond of declination (J2000) 26- 30 F5.2 mag Jmag J-band magnitude 32- 36 F5.2 mag Hmag H-band magnitude 38- 42 F5.2 mag Ksmag Ks-band magnitude 44- 45 A2 --- Group Group (A0, Ar or B) (2)
Note (1): Positions are from the J-H-Ks image (Figure 1). Note (2): Classification based on a color-color diagram (see Section 4.2).
Byte-by-byte Description of file: table2.dat
Bytes Format Units Label Explanations
1- 2 I2 --- Name Source name (<[KCP2010] NN> for Simbad) 4 A1 --- l_P(J) Limit flag on P(J) (3) 5- 9 F5.2 % P(J) J-band polarization 11- 15 F5.2 % e_P(J) ? P(J) uncertainty 17 A1 --- l_P(H) Limit flag on P(H) (3) 18- 22 F5.2 % P(H) H-band polarization 24- 27 F4.2 % e_P(H) ? P(H) uncertainty 29 A1 --- l_P(Ks) Limit flag on P(Ks) (3) 30- 34 F5.2 % P(Ks) Ks-band polarization 36- 39 F4.2 % e_P(Ks) ? P(Ks) uncertainty 41- 45 F5.1 deg PA(J) ? J-band polarization position angle 47- 49 F3.1 deg e_PA(J) ? PA(J) uncertainty 51- 55 F5.1 deg PA(H) ? H-band polarization position angle 57- 59 F3.1 deg e_PA(H) ? PA(H) uncertainty 61- 65 F5.1 deg PA(Ks) ? Ks-band polarization position angle 67- 69 F3.1 deg e_PA(Ks) ? PA(Ks) uncertainty
Note (3): For sources with P/δP<3, the 3δP upper limits are listed.
History: From electronic version of the journal
(End) Emmanuelle Perret [CDS] 10-Feb-2012
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