ALIGNMENT BETWEEN FLATTENED PROTOSTELLAR INFALL ENVELOPES AND AMBIENT MAGNETIC FIELDS

被引:89
作者
Chapman, Nicholas L. [1 ,2 ]
Davidson, Jacqueline A. [3 ]
Goldsmith, Paul F. [4 ]
Houde, Martin [5 ,6 ]
Kwon, Woojin [7 ,8 ]
Li, Zhi-Yun [9 ]
Looney, Leslie W. [7 ]
Matthews, Brenda [10 ,11 ]
Matthews, Tristan G. [1 ,2 ]
Novak, Giles [1 ,2 ]
Peng, Ruisheng [12 ]
Vaillancourt, John E. [13 ]
Volgenau, Nikolaus H. [14 ]
机构
[1] Northwestern Univ, CIERA, Evanston, IL 60208 USA
[2] Northwestern Univ, Dept Phys & Astron, Evanston, IL 60208 USA
[3] Univ Western Australia, Sch Phys, Crawley, WA 6009, Australia
[4] CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA
[5] Univ Western Ontario, Dept Phys & Astron, London, ON, Canada
[6] CALTECH, Div Phys Math & Astron, Pasadena, CA 91125 USA
[7] Univ Illinois, Dept Astron, Urbana, IL 61801 USA
[8] Univ Groningen, SRON Netherlands Inst Space Res, NL-9747 AD Groningen, Netherlands
[9] Univ Virginia, Dept Astron, Charlottesville, VA 22904 USA
[10] Natl Res Council Canada, Herzberg Inst Astrophys, Victoria, BC V9E 2E7, Canada
[11] Univ Victoria, Dept Phys & Astron, Victoria, BC V8P 1A1, Canada
[12] Caltech Submillimeter Observ, Hilo, HI 96720 USA
[13] NASA, Ames Res Ctr, Univ Space Res Assoc, SOFIA Sci Ctr, Moffett Field, CA 94035 USA
[14] CALTECH, Owens Valley Radio Observ, Big Pine, CA 93513 USA
基金
美国国家科学基金会;
关键词
ISM: jets and outflows; ISM: magnetic fields; stars: formation; techniques: polarimetric; 2-DIMENSIONAL RADIATIVE-TRANSFER; SINGULAR ISOTHERMAL TOROIDS; MOLECULAR CLOUD CORES; SMALL-SCALE STRUCTURE; CLASS; PROTOSTARS; STAR-FORMATION; BOK GLOBULES; INTERSTELLAR CLOUDS; YOUNG STARS; SHARC-II;
D O I
10.1088/0004-637X/770/2/151
中图分类号
P1 [天文学];
学科分类号
0704 ;
摘要
We present 350 mu m polarization observations of four low-mass cores containing Class 0 protostars: L483, L1157, L1448-IRS2, and Serp-FIR1. This is the second paper in a larger survey aimed at testing magnetically regulated models for core-collapse. One key prediction of these models is that the mean magnetic field in a core should be aligned with the symmetry axis (minor axis) of the flattened young stellar object inner envelope (aka pseudodisk). Furthermore, the field should exhibit a pinched or hourglass-shaped morphology as gravity drags the field inward toward the central protostar. We combine our results for the four cores with results for three similar cores that were published in the first paper from our survey. An analysis of the 350 mu m polarization data for the seven cores yields evidence of a positive correlation between mean field direction and pseudodisk symmetry axis. Our rough estimate for the probability of obtaining by pure chance a correlation as strong as the one we found is about 5%. In addition, we combine together data for multiple cores to create a source-averaged magnetic field map having improved signal-to-noise ratio, and this map shows good agreement between mean field direction and pseudodisk axis (they are within 15 degrees). We also see hints of a magnetic pinch in the source-averaged map. We conclude that core-scale magnetic fields appear to be strong enough to guide gas infall, as predicted by the magnetically regulated models. Finally, we find evidence of a positive correlation between core magnetic field direction and bipolar outflow axis.
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页数:14
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