1. Primera parte

2. Astronomical Polarimetry Optical and NIR applications Antonio Pereyra Observatório Nacional (ON) Rio de Janeiro - Brazil

3. LNA site

6. Polarimetry at LNA Instrument: IAGPOL –Polarimetric module –Operations modes: Imaging: –Point sources –Extended sources –Optical (w/ CCDs) –NIR (w/ CamIV) Spectropolarimetry –w/ EIFU (Integral Field Unit)

7. Retarder (λ/2 or λ/4) Analyser (Savart / Polaroid) Filters (Clear, U,B,V,R,I) Optical axis Wheel axis Detector (CCD, NIR – J,H,K) IAGPOL - Optical System

8. Measuring the Polarization Stokes parameters:

9. Measuring the Polarization Linear polarization: U’ (x100) P 2θ2θ Q’ (x100)

10. Transmitted intensity through waveplate /2 + Savart: Ni +Ni + Ni –Ni – I’(  i ) = ½ [I ± Q cos 4  i ± U sin 4  i ] I I’ Measuring the Polarization

11. Example: Crowded field

12. Modulation (waveplate+Savart)

13. HD110984 (optical polarized standard) Z  P R =(5.67  0.01)%@91. 3° (Tapia 88’) P = (Q’ 2 + U’ 2 ) ½  100 θ = ½ tan -1 (U’/Q’)

16. Applications

17. Interstellar Medium Unpolarized light from background star Aligned grain w/ angular momentum // B B Linear polarized light

18. Musca Dark Cloud Feitzinger & Stüve 84

19. MDC 2.5°x2.5 ° DSS

20. Pereyra & Magalhães 00 B ~ perpendicular to the longest axis of MDC Results support models of collapse along B

21. Pereyra & Magalhães 00 B ~ perpendicular to the longest axis of MDC Results support models of collapse along B

22. Pereyra & Magalhães 00 B ~ perpendicular to the longest axis of MDC Results support models of collapse along B

24. 2%2% 2MASS (H) DDS (optical) IRAS 12322- 7023 9’x9’ Pereyra & Magalhães 05 Optical vs NIR

25. Sigue segunda parte