SOFIA/HAWC polarimetry of low-mass YSOs

and their environs

SOFIA/HAWC polarimetry of low-mass YSOs

and their environs

SHARP

SOFIA/HAWC polarimetry of low-mass YSOs

and their environs

SHARP

Class 0

- molecular clouds have ordered B-fields- what is energy density, compared with… gravity? turbulence? rotation?- see Crutcher 2004 review article (CF, Zeeman)

- if fields are energetically important, they probably affect dynamical collapse of cores

Crutcher 2006

isolated, lo-mass SF

Crutcher 2006

1 - few thousand AU

isolated, lo-mass SF

Crutcher 2006

1 - few thousand AU

isolated, lo-mass SF

low-mass pinch in NGC 1333 IRAS4A(Girart, Rao, & Marrone 2006)

Class II YSO

low-mass pinch in NGC 1333 IRAS4A(Girart, Marrone, & Rao 2006)

Class II YSO

low-mass pinch in NGC 1333 IRAS4A(Girart, Marrone, & Rao 2006)

Class II YSO

why not morelo-mass pinches?

faint, small

why not more cases of B parallel to outflow?

maybe because very uniform fields are rare

more typical case is this prestellar core…(Kirk, Ward-Thompson, & Crutcher 2006)

…to find correlation between outflow and field, need to map field right where star is forming… within a few thousand AU.

will attempt with SHARP…

SHARP: 9 arcsec beam at 350 microns

9 arcsec is 1800 AU at 200 pc

(SCUBA polarimeter had 14 arcsec)

In comparison with 800 micron maps from the SCUBA polarimeter 350 micron observations are relatively more sensitive to warm dust near to the protostar,

criteria used for the Class 0 target list

distance < 400 pc

distance to nearest neighbor must be > 10,000 AU

preference for outflow axis nearly parallel to plane of sky

criteria used for the Class 0 target list

distance < 400 pc

distance to nearest neighbor must be > 10,000 AU

preference for outflow axis nearly parallel to plane of sky

target list of Class 0 YSOs for winterseason

(developed mainly by Brenda Matthews and Jackie Davidson)

goals of SHARP survey of Class 0YSOs

1. test for correlation of projected field direction with projected outflow direction

2. look for pinches (beam ~1800 AU @ 200 pc)

Both find < 2 for most TTS disks

goals of SOFIA/HAWCpol survey of Class 0 and Class I YSOs

1. test for correlation of projected field direction with projected outflow direction

2. look for pinches (beam ~ 900 AU @ 200 pc; 50m)

better ability to isolate the warmer inner regions

can trace evolution of B-field

get a 3D view