Detalles de publicación

PP 016075

QUIJOTE Scientific Results. II. Polarisation Measurements of the Microwave Emission in the Galactic molecular complexes W43 and W47 and supernova remnant W44

R. Génova-Santos (1,2), J. A. Rubiño-Martín (1,2), A. Peláez-Santos (1,2), F. Poidevin (1,2), R. Rebolo (1,2,3) , R. Vignaga (1,2), E. Artal (4), S. Harper (5), R. Hoyland (1), A. Lasenby (6,7), E. Martínez-González (8), L. Piccirillo (5), D. Tramonte (1,2), and R. A. Watson (5)
(1) Instituto de Astrofísıca de Canarias, 38200 La Laguna, Tenerife, Canary Islands, Spain (2) Departamento de Astrofísica, Universidad de La Laguna (ULL), 38206 La Laguna, Tenerife, Spain (3) Consejo Superior de Investigaciones Científicas, Spain (4) Departamento de Ingenieria de COMunicaciones (DICOM), Laboratorios de I+D de Telecomunicaciones Plaza de la Ciencia s/n, E-39005 Santander, Spain (5) Jodrell Bank Centre for Astrophysics, Alan Turing Building, School of Physics and Astronomy, The University of Manchester. Oxford Road, Manchester, M13 9PL, U.K (6) Astrophysics Group, Cavendish Laboratory, University of Cambridge, J.J. Thomson Avenue, Cambridge CB3 0HE, UK (7) Kavli Institute for Cosmology, Madingley Road, Cambridge, CB3 0HA (8) Instituto de Física de Cantabria (CSIC-Universidad de Cantabria), Avda. de los Castros s/n, 39005 Santander, Spain
We present Q-U-I JOint TEnerife (QUIJOTE) intensity and polarisation maps at 10 − 20 GHz covering a region along the Galactic plane 24º < l < 45º, |b| < 8º. These maps result from 210 h of data, have a sensitivity in polarisation of ≈40 μK/beam and an angular resolution of ≈ 1º. Our intensity data are crucial to confirm the presence of anomalous microwave emission (AME) towards the two molecular complexes W43 (22σ) and W47 (8σ). We also detect at high significance (6σ) AME associated with W44, the first clear detection of this emission towards a SNR. The new QUIJOTE polarisation data, in combination with WMAP, are essential to: i) Determine the spectral index of the synchrotron emission in W44, βsync = −0.62 ± 0.03, in good agreement with the value inferred from the intensity spectrum once a free-free component is included in the fit. ii) Trace the change in the polarisation angle associated with Faraday rotation in the direction of W44 with rotation measure −404 ± 49 rad /m2. And iii) set upper limits on the polarisation of W43 of Π_AME < 0.39 per cent (95 per cent C.L.) from QUIJOTE 17 GHz, and < 0.22 per cent from WMAP 41 GHz data, which are the most stringent constraints ever obtained on the polarisation fraction of the AME. For typical physical conditions (grain temperature and magnetic field strengths), and in the case of perfect alignment between the grains and the magnetic field, the models of electric or magnetic dipole emissions predict higher polarisation fractions.

 
Aceptado para publicación en MNRAS | Enviado el 2016-09-27 | Proyecto P/401199/03