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Magnetic fields in perturbed galaxies: a sensitive measure of external influences or

Some terminology: Regular magnetic field: a unidirectional one: RM 0 Pseudo-regular field: an anisotropic random one: <Bx 2 > > <By 2 > RM=0.

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Magnetic fields in perturbed galaxies: a sensitive measure of external influences or

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  1. Some terminology: Regular magnetic field: a unidirectional one: RM0 Pseudo-regular field: an anisotropic random one: <Bx2> > <By2> RM=0 • Magnetic fields in perturbed galaxies: a sensitive measure of external influences • or • Why to observe abnormal galaxies when we don’t yet fully understand normal ones?

  2. Prepared by Marek Urbanik • Based on observations made in cooperation with • K. Chyży, M. Soida, M. Weżgowiec, K. Otmianowska-Mazur - Astronomical Observatory, Jagiellonian University, Kraków • R. Beck – Max-Planck-Institut für Radioastronomie, Bonn • B. Vollmer - CDS, Observatoire Astronomique de Strasbourg • Ch. Balkowski - Observatoire de Paris, GEPI, CNRS, and Université Paris 7 • A. Chung - Smithsonian Astrophysical Observatory • J. van Gorkom - Department of Astronomy, Columbia University • J.D. Kenney - Yale University Astronomy Department

  3. 15% 10% 40% 1% NGC 4038/39 4.85 GHz DSS+TP+B-vec A merging pair The fundamental work by Chyży & Beck (2004) A&A, 417, 541 Courtesy K. Chyży HST image credit: B. Whitmore (STScI) and NASA

  4. NGC 4038/39 4.85 GHz DSS+TP+B-vec A merging pair The fundamental work by Chyży & Beck (2004) A&A, 417, 541 A highly polarized „collisionregion” A low-polarization hidden SF region A highly polarized, steep spectrum outflow region Courtesy K. Chyży

  5. A magnetic bridge? VLA TP conts + PI B-vecs VLA archive data Drzazga, Chyży in prep. NGC 877 Courtesy K. Chyży

  6. Knapik et. al. in prep. Note the vertically polarized plume north of the centre. Unlikely to be an AGN-borne jet as NGC 4490 is of late type. NGC4490/85 another interacting pair

  7. NGC 4490/85 a magnetized stream?? The vertically polarized structure north of the centre of NGC 4490 exactly corresponds in position and orientation (marked by a red line) with the HI spur seen there by Clemens et al. (1998 – ADS link here) and by Clemens & Alexander (2002 – ADS link here).

  8. NGC 3627 PV along this line and analogous along the NW arm Image credit: M. Neeser (Univ.-Sternwarte Munchen), P. Barthel (Kapteyn Astron. Institute), H. Heyer, H. Boffin (ESO), Pol. vectors – see Soida et al., 2001, A&A 378, 40 (VLA)

  9. NW normal region Diffuse CO(1-0) gas IRAM dish (Reuter et al. 1996) Clumpy CO(1-0) gas OVRO interf. (Soida et al. in prep) SE abnormal region Diifuse CO gas Clumpy CO gas

  10. Colour – clumpy cool gas seen by OVRO, conts – IRAM 1-0 upper panel: polarized intensity Colour – clumpy cool gas seen by OVRO, conts – HHT 3-2 upper panel: polarized intensity Data: OVRO inrerferometer (colour) – M. Soida, IRAM – Reuter et al. 1996 A&A 306, 721 CO(3-2) HHT – Krakow (M. Soida, M. Urbanik) + Bonn (M. Dumke, M. Krause, R. Wielebinski), in prep. A very personal remark: Without polarization observations probably these anomalies would remain unnoticed? All the analyses to be found in: Soida et al. in prep.

  11. Stephan’s Quintet Intergalactic hot X-ray gas pool See Trinchieri et al. 2003, A&A, 401, 173

  12. Bt = 7G Bu = 1.5 G Bt = 8G Bu = 2G Optical image credit: NASA, ESA, and the Hubble SM4 ERO Team Stephan’s Quintett Soida et al. in prep. Genuine intergalactic (quasi) regular magnetic field TP conts+PI B-vecs VLA 6cm

  13. Fractions of pol. flux on both sides of a major axis 15% 85% Motion? NGC 4501 in the Virgo Cluster TP+PI B-vecs, VLA 6cm Vollmer et al. + Kraków+Bonn& USA teams, 2007,A&A 464, L37

  14. NGC 4501 rectified: Assymmetry of the magnetic pitch angles Data from Vollmer et al. 2007 + Kraków+Bonn & USA teams

  15. Polarization used to constrain the model Vollmer et al.(incl. Krakow, Bonn & USA teams, 2008), A&A 483, 89

  16. ???? Colour - HI data: Phookun & Mundy 1995 ApJ, 453, 154, kindly provided by Dr Phookun NGC 4654 TP contours +PI vecs VLA 20cm Radio data Vollmer et al. (incl. Krakow, Bonn & USA teams) 2007 see also A&A 464, L37

  17. Edge-on „no reason” case NGC 4535 – in southern Virgo extension – a „no reason” face-on case Effelsberg 6 cm Weżgowiec et al., 2007, A&A 471, 93 Vollmer et al. (incl. Krakow, Bonn & NRAO teams) 2007 Galaxy motion? NGC 4402 blown from the bottom? TP conts + PI vecs VLA 6cm Vollmer et al. (+Krakow+Bonn+USA teams): Vollmer et al., 2010, A&A 512, A36

  18. Now green contours are TP while bars denote pol. int. B-vectors (VLA at 6cm) see Vollmer et al. (incl. Krakow, Bonn & USA teams), 2007,A&A 464, L37 Motion? NGC 4438 X-rays (green) M. Weżgowiec from archive NEWTON-XMM data

  19. Attempt to summarize • We have observed: • Magnetic bridges • Anomalous arms • Compressional ridges • Magnetized outflows • Intergalactic magnetic fields Magnetic field as seen in polarization is a very good „preselector” of anomalies to be studied in detail in other domains (X-rays, HI dynamics etc.)

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