J/ApJ/859/4 First-look analysis of ρ Oph-A at 850um (Kwon+, 2018)
A first look at BISTRO observations of the ρ Oph-A core.
Kwon J., Doi Y., Tamura M., Matsumura M., Pattle K., Berry D., Sadavoy S.,
Matthews B.C., Ward-Thompson D., Hasegawa T., Furuya R.S., Pon A., Di
Francesco J., Arzoumanian D., Hayashi S.S., Kawabata K.S., Onaka T.,
Choi M., Kang M., Hoang T., Lee C.W., Lee S.-S., Liu H.-L., Liu T.,
Inutsuka S.-I., Eswaraiah C., Bastien P., Kwon W., Lai S.-P., Qiu K.,
Coude S., Franzmann E., Friberg P., Graves S.F., Greaves J.S., Houde M.,
Johnstone D., Kirk J.M., Koch P.M., Li Di, Parsons H., Rao R.,
Rawlings M.G., Shinnaga H., van Loo S., Aso Y., Byun D.-Y., Chen H.-R.,
Chen M.C.-Y., Chen W.P., Ching T.-C., Cho J., Chrysostomou A., Chung E.J.,
Drabek-Maunder E., Eyres S.P.S., Fiege J., Friesen R.K., Fuller G.,
Gledhill T., Griffin M.J., Gu Q., Hatchell J., Holland W., Inoue T.,
Iwasaki K., Jeong I.-G., Kang J.-H., Kang S.-J., Kemper F., Kim G., Kim J.,
Kim K.-T., Kim K.H., Kim M.-R., Kim S., Lacaille K.M., Lee J.-E., Li D.,
Li H.-B., Liu J., Liu S.-Y., Lyo A.-R., Mairs S., Moriarty-Schieven G.H.,
Nakamura F., Nakanishi H., Ohashi N., Peretto N., Pyo T.-S., Qian L.,
Retter B., Richer J., Rigby A., Robitaille J.-F., Savini G., Scaife A.M.M.,
Soam A., Tang Y.-W., Tomisaka K., Wang H., Wang J.-W., Whitworth A.P.,
Yen H.-W., Yoo H., Yuan J., Zhang C.-P., Zhang G., Zhou J., Zhu L.,
Andre P., Dowell C.D., Falle S., Tsukamoto Y., Nakagawa T., Kanamori Y.,
Kataoka A., Kobayashi M.I.N., Nagata T., Saito H., Seta M., Zenko T.
<Astrophys. J., 859, 4 (2018)>
=2018ApJ...859....4K 2018ApJ...859....4K
ADC_Keywords: Polarization; Millimetric/submm sources; Molecular clouds;
Interstellar medium
Keywords: circumstellar matter; ISM: individual objects (Ophiuchi);
ISM: structure; polarization; radio continuum: ISM; stars: formation
Abstract:
We present 850µm imaging polarimetry data of the ρ Oph-A core
taken with the Submillimeter Common-User Bolometer Array-2 (SCUBA-2)
and its polarimeter (POL-2) as part of our ongoing survey project,
B-fields In STar forming RegiOns (BISTRO). The polarization vectors
are used to identify the orientation of the magnetic field projected
on the plane of the sky at a resolution of 0.01pc. We identify 10
subregions with distinct polarization fractions and angles in the
0.2pc ρ Oph-A core; some of them can be part of a coherent
magnetic field structure in the ρ Oph region. The results are
consistent with previous observations of the brightest regions of
ρ Oph-A, where the degrees of polarization are at a level of a few
percent, but our data reveal for the first time the magnetic field
structures in the fainter regions surrounding the core where the
degree of polarization is much higher (>5%). A comparison with
previous near-infrared polarimetric data shows that there are several
magnetic field components that are consistent at near-infrared and
submillimeter wavelengths. Using the Davis-Chandrasekhar-Fermi method,
we also derive magnetic field strengths in several subcore regions,
which range from approximately 0.2 to 5mG. We also find a correlation
between the magnetic field orientations projected on the sky and the
core centroid velocity components.
Description:
Continuum observations of ρ Oph-A at 850um were made by inserting
POL-2 into the optical path of SCUBA-2 on the James Clerk Maxwell
Telescope (JCMT) between 2016 April 15 and 2016 April 24. The region
was observed in 20 sets of 41 minutes observations.
Continuum polarimetric observations were simultaneously taken at 450um
with a resolution of 9.6". In this paper, we discuss the 850um data
only.
Objects:
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RA (ICRS) DE Designation(s)
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16 26 26.4 -24 22 33 ρ Oph-A = NAME rho Oph A Cloud
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File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 95 240 Submillimeter polarimetry in the ρ Ophiuchi
cloud core
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See also:
J/A+A/216/44 : Walraven photometry in Sco-Cen association (De Geus+, 1989)
J/ApJ/650/945 : Polarisation around filamentary dark cloud GF 9
(Poidevin+, 2006)
J/A+A/472/519 : N2H+(1-0) maps of Ophiuchus main cloud (Andre+, 2007)
J/ApJS/181/321 : Properties of Spitzer c2d dark clouds (Evans+, 2009)
J/ApJS/182/143 : SCUPOL Legacy polarimetry of SCUBA (Matthews+, 2009)
J/A+A/498/167 : Embedded sources in L 1688 (van Kempen+, 2009)
J/ApJS/186/406 : 350um polarimetry from CSO (Dotson+, 2010)
J/ApJ/708/758 : Polarimetry of HH1-2 region (Kwon+, 2010)
J/ApJ/741/35 : NIR photometry and polarization in NGC 2264 (Kwon+, 2011)
J/ApJ/793/126 : L204 - Cloud 3 polarimetry and photometry (Cashman+, 2014)
J/ApJ/783/1 : VRI and H polarization toward Sh 2-29 (Santos+, 2014)
J/ApJS/220/17 : Wide-field NIR polarimetry of ρ Oph cloud (Kwon+, 2015)
J/MNRAS/447/1996 : Ophiuchus molecular cloud CO observations (White+, 2015)
Byte-by-byte Description of file: table1.dat
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Bytes Format Units Label Explanations
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1- 3 I3 --- Seq [1/240] Souce index number (1)
5- 6 I2 h RAh [16] Hour of Right Ascension (J2000) (2)
8- 9 I2 min RAm [26] Minute of Right Ascension (J2000) (2)
11- 14 F4.1 s RAs [10/46] Second of Right Ascension (J2000) (2)
16 A1 --- DE- [-] Sign of the Declination (J2000) (2)
17- 18 I2 deg DEd [24] Degree of Declination (J2000) (2)
20- 21 I2 arcmin DEm [17/26] Arcminute of Declination (J2000) (2)
23- 27 F5.2 arcsec DEs Arcsecond of Declination (J2000) (2)
29- 36 F8.3 mJy/beam I [34/3403] Stokes I intensity; mJy/beam
38- 42 F5.3 mJy/beam e_I [1.9/7.6] Uncertainty in I
44- 50 F7.3 mJy/beam Q [-14/27] Stokes Q intensity; mJy/beam
52- 56 F5.3 mJy/beam e_Q [1.2/5] Uncertainty in Q
58- 64 F7.3 mJy/beam U [-76/25] Stokes U intensity; mJy/beam
66- 70 F5.3 mJy/beam e_U [1.2/5.1] Uncertainty in U
72- 76 F5.2 % P [0.2/26.7] Polarization
78- 81 F4.2 % e_P [0.04/4] Uncertainty in P
83- 87 F5.1 deg theta [-89/85] Polarization position angle
89- 92 F4.1 deg e_theta [0.5/12.4] Uncertainty in theta
94 A1 --- Comp [a-j] Component region shown in Figure 8
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Note (1): Sources are sorted by declinations.
Sources with I>0, P/e_P>2, and e_P<4 are listed.
Note (2): Positions are from the Stokes I image (Figure 1).
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History:
From electronic version of the journal
(End) Prepared by [AAS], Emmanuelle Perret [CDS] 03-Apr-2019