2019A&A...630A..74M


Query : 2019A&A...630A..74M

2019A&A...630A..74M - Astronomy and Astrophysics, volume 630A, 74-74 (2019/10-1)

The geometry of the magnetic field in the central molecular zone measured by PILOT.

MANGILLI A., AUMONT J., BERNARD J.-P., BUZZELLI A., DE GASPERIS G., DURRIVE J.B., FERRIERE K., FOENARD G., HUGHES A., LACOURT A., MISAWA R., MONTIER L., MOT B., RISTORCELLI I., ROUSSEL H., ADE P., ALINA D., DE BERNARDIS P., DE GOUVEIA DAL PINO E., DUBOIS J.P., ENGEL C., GUILLET V., HARGRAVE P., LAUREIJS R., LONGVAL Y., MAFFEI B., MAGALHES A.M., MARTY C., MASI S., MONTEL J., PAJOT F., PEROT E., RODRIGUEZ L., SALATINO M., SACCOCCIO M., SAVINI G., STEVER S., TAUBER J., TIBBS C. and TUCKER C.

Abstract (from CDS):

We present the first far infrared (FIR) dust emission polarization map covering the full extent of Milky Way's central molecular zone (CMZ). The data, obtained with the PILOT balloon-borne experiment, covers the Galactic center region - 2°<l<2°, -4°<b<3° at a wavelength of 240µm and an angular resolution of 2.2'. From our measured dust polarization angles, we infer a magnetic field orientation projected onto the plane of the sky (POS) that is remarkably ordered over the full extent of the CMZ, with an average tilt angle of ∼22° clockwise with respect to the Galactic plane. Our results confirm previous claims that the field traced by dust polarized emission is oriented nearly orthogonally to the field traced by GHz radio synchrotron emission in the Galactic center region. The observed field structure is globally compatible with the latest Planck polarization data at 353 and 217GHz. Upon subtraction of the extended emission in our data, the mean field orientation that we obtain shows good agreement with the mean field orientation measured at higher angular resolution by the JCMT within the 20 and 50km/s molecular clouds. We find no evidence that the magnetic field orientation is related to the 100pc twisted ring structure within the CMZ. The low polarization fraction in the Galactic center region measured with Planck at 353 GHz combined with a highly ordered projected field orientation is unusual. This feature actually extends to the whole inner Galactic plane. We propose that it could be caused by the increased number of turbulent cells for the long lines of sight towards the inner Galactic plane or to dust properties specific to the inner regions of the Galaxy. Assuming equipartition between magnetic pressure and ram pressure, we obtain magnetic field strength estimates of the order of 1mG for several CMZ molecular clouds.

Abstract Copyright: © A. Mangilli et al. 2019

Journal keyword(s): Galaxy: center - polarization - magnetic fields - balloons - methods: data analysis - dust, extinction

Simbad objects: 6

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Number of rows : 6
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 Galactic Center reg 17 45 39.60213 -29 00 22.0000           ~ 13547 0
2 NAME Sgr A* X 17 45 40.03599 -29 00 28.1699           ~ 4089 3
3 NAME Sgr A East Rad 17 45 41 -29 00.8           ~ 484 2
4 NAME the Brick MoC 17 46 09 -28 43.8           ~ 181 0
5 NAME Sgr B2 MoC 17 47 20.4 -28 23 07           ~ 2162 1
6 NAME Galactic Bar reg ~ ~           ~ 1126 0

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2023.03.22-21:03:20

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