SO04 (WD, Terada)

Welcome to our Session (SO04) !

Photo in City Hole Stockholm, 3 July 2012 reception

The parallel session of 13th Marcel Grossmann Meeting

White Dwarf Pulsars and Rotating White Dwarf Theory

SO04 (WD, Terada)

Scope of this session Original Simple Question Why we do not have White Dwarf Pulsars? Related Questions How can we feedback to Neutron Star Science? (structure of magnetosphere, emission mechanism, death line, diversity of NSs)

What is the impact on Astrophysics? (Origin of Cosmic-rays: 100 years celebration from the discovery !)

What is the impact to extreme physics? (Internal structure, Equation of state, of white dwarfs)

The parallel session of 13th Marcel Grossmann Meeting

White Dwarf Pulsars and Rotating White Dwarf Theory

To answer them is the scope of ...

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SO04 (WD, Terada)

Goal of this session

Shareing our knowledge on white dwarfs Discussion on topics (5 min per talk)

Working together important Interactions between our tasks in this field is important! 1. Know each other 2. Making working group (or mailing list) to exchange information

3. Do not miss the dead line of proceedings, on 28 Feb 2013 !

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Review on High Energy observations in searches for Non-thermal emissions

from Accelerated particles in Magnetic White Dwarfs

Yukikatsu Terada (Saitama University, Japan)

SO04 (WD, Terada)

1. Review on white dwarf pulsars

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SO04 (WD, Terada)

Simple Idea: similarity between NS and WD

WDs can accelerate particles showing non-thermal emission.

White Dwarf Pulsar

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SO04 (WD, Terada)

First Proposal of WD pulsar in 1969

• Original interest was the ORIGIN of COSMIC-RAY. (NS cannot generate low-energy particles in GeV, only WD can do.)

Same year as the pulsar theory by Goldreich and Julian 1969

1969 ICRC

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SO04 (WD, Terada)

First estimation of the contribution to CR 1971 ICRC

CR heavy ions

CR electrons 1971 ICRC

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SO04 (WD, Terada)

Found in the Hillas diagram Makishima 2008

Emax = e v B L ~ 6x1016(P/1s)-1(B/1012G)(L/106cm)2 eV (NS)

So, the idea of WD Pulsar should be quite natural .

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MWD

Maxim

um E

nerg

y (

eV)

Blazer

Magnetic CVs

Globular Cluster

Solar flare

Winter thander

Crab

Magnetic storm

Inversive Magnetic Pinch

SO04 (WD, Terada)

Observational approaches in 1980-1990s Radio Survey • Non-thermal incoherent radio emissions found in 7 WDs (Nelson&Spencer 88, Beasley+ 94, Pavelin+94, Bond+02, Mason&Gray 07) • Coherent radio emissions from AE Aqr and AM Her

(Bastian+88, Abada-Simon+93, Chanmugam&Dulk 82,Dulk+83) Suggesting 1-100 MeV electrons

Gamma-ray survey • AE Aqrii is listed among 5 sources in the first TeV catalog. (Currently NOT) • First detection of TeV from AE Aqr (Meintjes+92, 93) and AM Her (Bhat+91) in flare • Many Report of TeV detections from AE Aqr, independently (Bowden+92 ,Chadwick +95)

• No confirmation with long observation by Whipple (Lang+98)

Difficulties in “Single dish, non-imaging ” γ-ray telescopes

No WD Pulsars ??

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Whipple

SO04 (WD, Terada)

Theoretical predictions in 1990-2000s Interpretation as “mille-second pulsar” equivalent (de Jager 94)

• Idea for a magnetic white dwarf binary, AE Aqr. • High Spin down (33 s, 10-13 s/s, Lsd = 6 x 1033 erg/s) (de Jager+ 94, Mauche+06) • Low accretion, no disk, propeller effect (Wynn+97) to make lower than nGJ

Interpretation of high spin down luminosity of AE Aqr • High magnetic field strength (Bs = 50MG) (Ikhsanov 98, 99) • Verification by Doppler Hα tomogram (Ikhsanov+ 04, Ikhsanov and Beskrovnaya 08) • Estimation of X-ray and Gamma-ray from AE Aqr (Ikhsanov and Biermann 06)

Based on standard NS pulsar theories. + Magnetic reconnection.

Idea of “magnetars” equivalent? • Why we have so many diverse in NSs? • WDs comes in magnetars area

(Terada & Dotani 11) Lbol > Ldp ? (Lbl ~ 0.1% of Lsd )

• New Class of magnetic CVs? (Ikhsanov & Beskrovnaya 12)

• Magnetars as MWD? (Malheiro+12)

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SO04 (WD, Terada)

Observational searches,again, after 2005 Discovery of non-thermal Radio (Zhang & Gil 05)

•radio transient in Galactic Center region, GCRT J1745-3009

Searches for non-thermal emission in X-ray • Suzaku discovery of hard X-ray pulsation (Terada +08) (later)

Searches for non-thermal emission in TeV gamma-ray band

• No TeV emission with MAGIC (Sidro+08) • Simultaneous campaign of AE Aqr with Chandra & MAGIC (Mauche+11 ) • Simultaneous campaign of AE Aqr with Suzaku & H.E.S.S. (Terada+) (later)

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SO04 (WD, Terada)

2. Suzaku searches for non-thermal emission from WDs.

Collaborators: Y. Terada, A. Harayama (Saitama Univ. Japan), T. Hayashi, T. Dogtani, M. Ishida (ISAS/JAXA, Japan), A. Bamba (Aoyama Gakuin, Jp), K. Makishima (U.Tokyo, Jp), K. Mukai (NASA/GSFC, USA), Y. Urata (Taiwan Cent Univ, Taiwan), A. Nitta (Gemini Observatory, USA), Okkie de Jager(North-West Univ, South Africa), Paula Chadwick(Durham Univ, UK) , Stefan Wagner(LSW, Germany), David Buckley(Univ.of Cape Town, South Africa)

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SO04 (WD, Terada)

Breakthrough: Suzaku discovery of hints

Neutron Star (Crab)

White Dwarf (AE Aqr)

Enhances at soft X-ray flares

(1) Sharp Pulse profile like NSs!

Object: AE Aqr (Intermediate Polar) Suzaku observation: Oct 2005 (SWG), 70 ksec

Terada+ 2008

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SO04 (WD, Terada)

Spectral property of the Hard X-ray pulses

Phase resolved spectra

(2) No Thermal lines in the Pulse spectrum in over 2 keV band.

Peak

Becker and Trumper 1999 Possenti et al 2002

Luminosity of Pulse component

AE Aqr

Spin down energy (erg/s) X-

ray

Flux

(erg

/s)

(3) Similar photon index and fraction to spin down energy as NS case

Possible non-thermal emission from AE Aqr

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SO04 (WD, Terada)

Isolated WDs ① Known P and B, highest Ldp, EUVE J0317-85.5 (2010, 60 ks)

② ROSAT candidate, EUVE J1439 +75.0 (2012, 40 ks)

③ ROSAT candidate, PG 1658 +440 (2012, 50 ks)

And beyond.. Binary system (MCVs) ① Another TeV source, AM Her, in low state (2008, 100 ks) (Terada +10)

② Simultaneous observation of AE Aqr with Optical + Suzaku + H.E.S.S.(2009, ToO 160ks) (Next Viewgraph)

③ hard catalog by INTEGRAL, IGRJ00234+6141 (2010, 80 ks)

④ hard catalog in Swift BAT, V2487 Oph (2010, 50 ks) thermal

Pulsar Non-thermal?

E ※ Rejection of thermal emission is the key for searches

Harayama talk

star accretion wd

Hayashi talk

NS WD

ms pulsars AE Aqr, MCVs

Radio pulsars Isolated WDs?

(de Jager 94)

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SO04 (WD, Terada)

Multi-wave campaign of AE Aqr • First Guest observation with H.E.S.S (8 hr, 6 nights) • Long observation with Suzaku(net 160 ksec, 400 ksec in total), • Optical telescope network • Date: 14 – 21 Oct, 2009

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SO04 (WD, Terada)

Results in multi-wave campaign • [Gamma] Very short exposure with H.E.S.S., due to bad weather • [X] Suzaku observation was competed (5 days!) • [Opt] bad weather, but partially overlapping with Suzaku

Light Curve in X-ray

Several flares in X-ray Good correlation between X-opt, especially for soft X-rays

Energy (keV) Time (s)

Flare

Soft

X

Hard

X

1000 s

Optical

Soft

X-ra

y C

ross-col.

0.7 – 3 keV

Optial

SAAO

Turkey

<2keV

>2keV

1 day

0.5-1 keV

1-2 keV

2-4keV

4-6 keV

6-10keV

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SO04 (WD, Terada)

X-ray spectra

Top/Bottom

Pulsed

Fe

Ne, Fe Mg

Ar S

Si O

•Phase resolved X-ray spectra with Suzaku (70 ksec+50 ksec+160 ksec)

Top & Bottom

No plasma lines in PULSED spectrum Non thermal !!

1.8x1030 erg/s @102pc 0.5-10keV = 0.5% of LSD(confirmed)

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SO04 (WD, Terada)

3. Summary List of Questions

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SO04 (WD, Terada)

List of questions to you all in this room Do we really have WD pulsars?

• Please show current observational attempts (Terada, Hayashi, Harayama, Meregetti) • Please show plans with newly born and/or near future missions (Kitaguchi, others) • Can we expect non-thermal emissions from WD pulsars? Death line?(Wada, Ikhsanov) • Is it Pulsar-like emission and/or PWN-like emission?

Can we feedback to NS pulsar science?

• What is the similarity between NS and WD? Especially for magnetars? (Malheiro, Coelho, Achille) • What is the difference between NS and WD? (Wada) • Do we have some hints on question why we have so many kinds of NS pulsars, when they are simply rotating magnets? (all)

What is the impact to astrophysics ? (Origin of cosmic-rays, 100 years from the discovery)

• Electron and positron source? (Kashiyama) What is the impact to extreme physics? (Internal structure of WDs)

• What is the internal structure of WD. (Boshkayev, Simonetta, Upasana, Sheyse)

Let’s start and enjoy the session !!

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