2015A&A...576A.105P

Query : 2015A&A...576A.105P

2015A&A...576A.105P - Astronomy and Astrophysics, volume 576A, 105-105 (2015/4-1)

Planck intermediate results. XX. Comparison of polarized thermal emission from Galactic dust with simulations of MHD turbulence.

PLANCK COLLABORATION, ADE P.A.R., AGHANIM N., ALINA D., ALVES M.I.R., ANIANO G., ARMITAGE-CAPLAN C., ARNAUD M., ARZOUMANIAN D., ASHDOWN M., ATRIO-BARANDELA F., AUMONT J., BACCIGALUPI C., BANDAY A.J., BARREIRO R.B., BATTANER E., BENABED K., BENOIT-LEVY A., BERNARD J.-P., BERSANELLI M., BIELEWICZ P., BOND J.R., BORRILL J., BOUCHET F.R., BOULANGER F., BRACCO A., BURIGANA C., CARDOSO J.-F., CATALANO A., CHAMBALLU A., CHIANG H.C., CHRISTENSEN P.R., COLOMBI S., COLOMBO L.P.L., COMBET C., COUCHOT F., COULAIS A., CRILL B.P., CURTO A., CUTTAIA F., DANESE L., DAVIES R.D., DAVIS R.J., DE BERNARDIS P., DE ROSA A., DE ZOTTI G., DELABROUILLE J., DICKINSON C., DIEGO J.M., DONZELLI S., DORE O., DOUSPIS M., DUPAC X., EFSTATHIOU G., ENSSLIN T.A., ERIKSEN H.K., FALGARONE E., FANCIULLO L., FERRIERE K., FINELLI F., FORNI O., FRAILIS M., FRAISSE A.A., FRANCESCHI E., GALEOTTA S., GANGA K., GHOSH T., GIARD M., GIRAUD-HERAUD Y., GONZALEZ-NUEVO J., GORSKI K.M., GREGORIO A., GRUPPUSO A., GUILLET V., HANSEN F.K., HARRISON D.L., HELOU G., HERNANDEZ-MONTEAGUDO C., HILDEBRANDT S.R., HIVON E., HOBSON M., HOLMES W.A., HORNSTRUP A., HUFFENBERGER K.M., JAFFE A.H., JAFFE T.R., JONES W.C., JUVELA M., KEIHAENEN E., KESKITALO R., KISNER T.S., KNEISSL R., KNOCHE J., KUNZ M., KURKI-SUONIO H., LAGACHE G., LAMARRE J.-M., LASENBY A., LAWRENCE C.R., LEONARDI R., LEVRIER F., LIGUORI M., LILJE P.B., LINDEN-VORNLE M., LOPEZ-CANIEGO M., LUBIN P.M., MACIAS-PEREZ J.F., MAINO D., MANDOLESI N., MARIS M., MARSHALL D.J., MARTIN P.G., MARTINEZ-GONZALEZ E., MASI S., MATARRESE S., MAZZOTTA P., MELCHIORRI A., MENDES L., MENNELLA A., MIGLIACCIO M., MIVILLE-DESCHENES M.-A., MONETI A., MONTIER L., MORGANTE G., MORTLOCK D., MUNSHI D., MURPHY J.A., NASELSKY P., NATI F., NATOLI P., NETTERFIELD C.B., NOVIELLO F., NOVIKOV D., NOVIKOV I., OXBORROW C.A., PAGANO L., PAJOT F., PAOLETTI D., PASIAN F., PELKONEN V.-M., PERDEREAU O., PEROTTO L., PERROTTA F., PIACENTINI F., PIAT M., PIETROBON D., PLASZCZYNSKI S., POINTECOUTEAU E., POLENTA G., POPA L., PRATT G.W., PRUNET S., PUGET J.-L., RACHEN J.P., REINECKE M., REMAZEILLES M., RENAULT C., RICCIARDI S., RILLER T., RISTORCELLI I., ROCHA G., ROSSET C., ROUDIER G., RUSHOLME B., SANDRI M., SCOTT D., SOLER J.D., SPENCER L.D., STOLYAROV V., STOMPOR R., SUDIWALA R., SUTTON D., SUUR-USKI A.-S., SYGNET J.-F., TAUBER J.A., TERENZI L., TOFFOLATTI L., TOMASI M., TRISTRAM M., TUCCI M., UMANA G., VALENZIANO L., VALIVIITA J., VAN TENT B., VIELVA P., VILLA F., WADE L.A., WANDELT B.D. and ZONCA A.

Abstract (from CDS):

Polarized emission observed by Planck HFI at 353GHz towards a sample of nearby fields is presented, focusing on the statistics of polarization fractions p and angles ψ. The polarization fractions and column densities in these nearby fields are representative of the range of values obtained over the whole sky. We find that: (i) the largest polarization fractions are reached in the most diffuse fields; (ii) the maximum polarization fraction p_max decreases with column density N_H in the more opaque fields with N_H>10²¹cm^–2; and (iii) the polarization fraction along a given line of sight is correlated with the local spatial coherence of the polarization angle. These observations are compared to polarized emission maps computed in simulations of anisotropic magnetohydrodynamical turbulence in which we assume a uniform intrinsic polarization fraction of the dust grains. We find that an estimate of this parameter may be recovered from the maximum polarization fraction p_max in diffuse regions where the magnetic field is ordered on large scales and perpendicular to the line of sight. This emphasizes the impact of anisotropies of the magnetic field on the emerging polarization signal. The decrease of the maximum polarization fraction with column density in nearby molecular clouds is well reproduced in the simulations, indicating that it is essentially due to the turbulent structure of the magnetic field: an accumulation of variously polarized structures along the line of sight leads to such an anti-correlation. In the simulations, polarization fractions are also found to anti-correlate with the angle dispersion function S. However, the dispersion of the polarization angle for a given polarization fraction is found to be larger in the simulations than in the observations, suggesting a shortcoming in the physical content of these numerical models. In summary, we find that the turbulent structure of the magnetic field is able to reproduce the main statistical properties of the dust polarization as observed in a variety of nearby clouds, dense cores excluded, and that the large-scale field orientation with respect to the line of sight plays a major role in the quantitative analysis of these statistical properties.

Abstract Copyright: ∼

Journal keyword(s): ISM: general - dust, extinction - ISM: magnetic fields - ISM: clouds - infrared: ISM - submillimeter: ISM

Simbad objects: 13

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Number of rows : 13

N	Identifier	Otype	ICRS (J2000) RA	ICRS (J2000) DEC	Mag U	Mag B	Mag V	Mag R	Mag I	Sp type	#ref 1850 - 2023	#notes
1	NAME PSC CL	ClG	00 58 25.0	+30 39 11						~	129	1
2	* alf UMi	cC*	02 31 49.09456	+89 15 50.7923	3.00	2.62	2.02	1.53	1.22	F8Ib	663	2
3	NAME Perseus Cloud	SFR	03 35.0	+31 13						~	1291	0
4	NAME Taurus Complex	SFR	04 41.0	+25 52						~	4175	0
5	M 42	OpC	05 35 17	-05 23.4						~	3999	0
6	NAME Polaris Flare	MoC	11 00 14.8	+86 10 52						~	185	1
7	NAME Chamaeleon Region	SFR	11 55	-78.0						~	770	0
8	NAME Cha-Mus	DNe	12 15	-76.7						~	36	0
9	NAME Musca	Cld	12 23	-71.3						~	206	0
10	NAME Ophiuchus Molecular Cloud	SFR	16 28 06	-24 32.5						~	3497	1
11	NAME MICROSCOPIUM SUPERCL	SCG	20 36	-34.8						~	10	0
12	NAME Pavo Field	reg	21 14	-57.8						~	18	0
13	NAME Ara	reg	~	~						~	19	0

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