Magnetism in Heaven and Earth Bryan Gaensler Institute for Astronomy Stern und Weltraum / Beck et al. Hubble Heritage Travels Travels John Mandeville’s John Mandeville’s Overview

1.! Magnets on Earth 2.! Magnets in the Heavens 3.! A short wishlist 4.! The future Thales and Sushruta

›! Thales of Miletus (~624 – ~546 BCE): -! “! µ"#$%&'( )*+,( -./' 01.%$, 2'3&' 4'$/* &,$ 5*267,$.” (Aristotle, De Anima) www.daviddarling.info © Science-Scientists’ Visuals ›! Sushruta (Indian surgeon, ~600 BCE): -! “A loose, unbarbed arrow, lodged in a wound … should be withdrawn by applying a magnet to its end.” (Sushruta Samhita 27) China cultural- china.com ›! Wang Xu (~400 BCE) (“Master of Ghost Valley”) -! “The lodestone attracts iron.” (Gui Gu Zi 2)

›! Liu An (179-122 BCE) -! “If you think that because the lodestone can attract iron you can also make it attract pieces of pottery, you will find yourself mistaken. Things cannot be judged merely in terms of weight, they have special and peculiar properties. Such effects are very hard to understand.” (Huainanzi 6) xinfajia.net Europe and Persia

›! Alexander of Neckam (1157-1217) -! “A ship must have a needle mounted on a pivot which will oscillate and turn until the

Travels Travels point looks to the north. The sailors will thus know how to direct their course when the polar star is concealed.” (De Utensilibus) John Mandeville’s John Mandeville’s © Sean Sprague / spraguephoto.com ›! Zahiriddin Muhammad Aufi (1171-1242) -! “The sea captain had taken the wrong path. He immediately brought out a hollow iron in the shape of a fish and threw it in a bowl with water. It turned and came towards the south.” (Jawami ul-Hikayat) Mexican Magnetism!

›! Sculpture of sea turtle with magnetic head, ~300 BCE – 100 CE (Malmstrom 1976) Malmstrom (1976)

›! “M-160”: polished magnetic bar, magnetic field and grooves both aligned with axis, ~1400-1000 BCE (Carlson 1975; Evans 1977) ancient- wisdom.co.uk authenticmaya.com ›! “Fat Boys”: magnetite sculptures with magnetic pole at temple or navel; stone jaguar, magnetic poles in paws, ~2000 BCE (Malmstrom 1997; Guimarães 2004) Terrestrial Magnetism

› Birds: retinal magneto-reception ! Begall et al. (2008) (Mouritsen et al. 2004; Ritz et al. 2004) ›! Cows: align with Earth’s field when grazing or resting (Begall et al. 2008)

›! Humans! Bones in sinus contain ferric iron; Crocker & Samarth (1997) duration of REM sleep depends on orientation (Baker et al. 1983; Ruhenstroth-Bauer et al. 1987) ›! Tesla Hybrid Magnet, Florida State: 450 kG (2800 L of liquid He, P = 33 MW) ›! Multishot Magnet, Los Alamos:

889 kG for 15 ms (Crocker & Samarth 1997) Boyko et al. (1998) ›! MC-1, Sarov, Russia: 28 MG for ~1 µs (170 kg of explosives; “these experiments definitely have to be performed outdoors”) (Boyko et al. 1998) Magnets in the Sky?

›! Alfvén (1937): cosmic ray confinement implies “the Lowell Observatory Archives / ASP / Yerkes Observatory existence of a magnetic field in interstellar space” ›! Babcock (1947): Zeeman splitting in other stars ›! Fermi (Jan 1949): “the main process of acceleration [of cosmic rays] is due to magnetic fields which occupy interstellar spaces … the magnetic field in the dilute matter is of the order of 5x10-6 gauss, while its intensity is probably greater in the heavier clouds” ›! Hall, Hiltner (Feb 1949): starlight is polarized ›! Davis & Greenstein (Mar 1949): “the polarization is not a property of the star but is produced while the

light is traversing extensive regions of interstellar Hall (1949) space … non-spherical dust grains produce [this if] there exists a general galactic magnetic field” ›! Kiepenheuer (June 1950): Galactic radio emission comes from cosmic rays gyrating in magnetic fields The Dawn of Radio Polarimetry

›! Razin (1956, 1958), Thompson (1957), Pawsey & Harting (1960): attempts to detect polarisation & Faraday rotation in Galactic radio emission ›! Bolton & Wild (1957): “large radio reflectors [offer] the possibility of determining longitudinal fields in localized interstellar regions by observing the Zeeman splitting of the 21-cm line” ›! Westerhout et al. (1962), Wielebinski et al. (1962): detection of polarisation of diffuse Galactic radio emission ›! Cooper & Price (1962): Detection of interstellar Faraday rotation against lobes of Centaurus A ›! Verschuur (1968): Detection of H I Zeeman splitting; “Fields of the order of 2x10-5 G exist in the Perseus spiral arm in the direction of the radio source Parkes polarimetry of Centaurus A Cassiopeia A.” (shortest abstract of all time?) (Cooper & Price 1962) Extremes of Cosmic Magnetism Magnetic filaments in ›! High-z seed fields B ~10-30 –10-20 G (Widrow 2002; Subramanian 2007) (Fabian et al. 2008) ›! Intergalactic Medium B ~ 1-10 nG ? › Intracluster Medium B ~ 0.1-1 µG ! Perseus A ›! Interstellar medium B ~ 1 µG – 10 mG ›! Galactic Centre B ~ 50 µG – 1 mG

(Crocker et al. 2010; Ferrière 2010) (Yusef-Zadeh et al. 1984)

›! Main sequence star: HD 215441 B0 8 34 kG Galactic Centre (Babcock 1960) 9 ›! White dwarf: PG 1031+234 B0 8 10 G (Schmidt et al. 1986) 13 ›! : PSR J1847-0130 B0 8 9 x 10 G (McLaughlin et al. 2003) SGR 1806-20 giant flare 15 ›! : SGR 1806-20 B0 8 2 x 10 G, 16 (Kouveliotou et al. 1998, Israel et al. 2005) Bi 8 10 G (NASA) ›! Cosmic strings (Ostriker et al. 1986) B ~ 1030 G ›! Planck-mass monopoles B ~ 1055 G (Duncan et al. 2000) Wishlist #1: Origin of B in Neutron Stars

-2 -1 ›! Fossil field of progenitor star? (B ! R , EB ! R ) (Ginzburg 1964; Ferrario & Wickramasinghe 2006)  -! !magnetar 0.1 !NS , but few known massive stars have " ~ "magnetar -! neutron star spin: " or J conserved, but not both (Spruit & Phinney 1998) "1 Ori C, B ~ 1100 G (Donati et al. 2002) -! can’t explain vs. high-B (Pivovaroff et al. 2000; Kaspi & McLaughlin 2005)

-2 ›! Dynamo in proto-neutron star? (EB ! Erot ! R ) (e.g., Duncan & Thompson 1992) -! strong magnetic field 9 rapid initial rotation -! energetics of SNRs around magnetars rule out P0 ~ 1-3 ms (Vink & Kuiper 2006) Magnetar 1E2259+586 and SNR CTB 109 (Sasaki et al. 2004) Wishlist #2: Magnetic Shielding

›! Correspondence of warm and cold H I in ISM (McClure-Griffiths et al. 2010) ›! Survival of high-velocity clouds in Galactic halo RM through HVC ›! Temperature discontinuities in clusters Abell 754 ( X-ray temperature map of Markevitch et al. 2003)

Galactic H I emission and absorption (Strasser et al. 2007) Wishlist #3: Growth Time of Galactic B

›! How quickly do fields grow? Kronberg et al. (2008) ›! How quickly can fields replenish themselves? ›! Field strength vs. field scale? (Gaensler et al. 2005) RMs through LMC Arshakian et al. (2009) ASKAP POSSUM

›! Polarisation Sky Survey of the Universe’s Magnetism

-! PIs Bryan Gaensler, Tom Landecker, Russ Taylor CSIRO / Swinburne -! ~50 scientists from 12 countries

›! All-sky (2 < +30o) ASKAP survey of polarised continuum, over 1150-1450 MHz to 10 µJy rms at 18: resolution -! RMs for ~3 million sources (~100 RMs/deg2) -! six months into Design Study

›! Four science goals: -! magneto-ionic properties of ISM & its components CSIRO / M. Whiting -! structure & geometry of large-scale B of -! magnetic properties of , AGN & clusters -! evolution of magnetic fields with cosmic time

http://www.physics.usyd.edu.au/sifa/possum