x-ray spectroscopy of classical novaedaitakei.com/common/files/presentation_cfa_20100421a.pdfat...

http://photojournal.jpl.nasa.gov/archive/PIA09221.mov

X-ray Spectroscopy of Classical Novae

Dai TakeiRikkyo University

Harvard-Smithsonian CfA Seminar, 2010.04.21

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謝辞

セミナーにご招待戴き... for inviting me to the seminar !!

ありがとうございます !!Thank you very much ...

謝辞 (Acknowledgement)

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Classical Novaelate-type dwarf

orgiant

(IR ～ Optical)

white dwarf(X-rays)

accretion disc(Optical ～ UV)


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photosphere(Optical ～ UV)(Optical)


?

photosphere(Optical ～ UV)

dust ?(Near-IR)

① photosphere(super-soft X-ray)

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② shock(thermal X-ray)


③ acc. particles ?(non-thermal X-ray)

① photosphere(super-soft X-ray)

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Talk Plan

1. Classical Novae

1. Introduction

2. Science Strategy

2. Observations

a. Observatories

b. Results with the Suzaku satellite

3. Future works

4. Summary

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CO ONe

(Heavy)(Light)

• Degenerate star (electron degenerate)- Mass limit : Mch ～ 1.4 M。 (Chandrasekhar 1931)

• Mass-Radius relation- More massive WDs are smaller (Nauenberg 1972)

Primary Star (White Dwarf)

.

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Mechanisms of Classical Novae

CO ONe

accretion(H-rich material)

high pressure & temperatureat white dwarf surface

(Heavy)(Light)

TNR : Thermo Nuclear Runaway

Mixing?

TNR

Mixing?

TNR

accretion(H-rich material)

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Mechanisms of Classical Novae

CO ONe

C

N

ONeMg

Si

CN

O

Super-SoftX-rays

Hard X-rays

Nuclearfuel

(Heavy)(Light)

Ejecta( nuclear products + WD material )

Mixing ... ?

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Radio

IR

Example of Light Curve

Bode, M. F. 2009, Astronomische Nachrichten, in press. (arXiv:0911.5254)

① super-soft X-ray

② thermal X-ray

??

Duration of the photospheric emissionis a function of WD mass !!

③ non-thermal X-ray ?


Point of Views : Classical Novae

• Hard X-rays (from shock of the ejecta ?)- Fast evolution- Weak source- Emission lines in the spectra ...?

• Photospheric Super-Soft X-rays- SSX time scale depends on WD mass- Absorption lines by WD atmosphere

• Behavior unpredictable- Observations difficult to schedule !!

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Talk Plan

1. Classical Novae

1. Introduction

2. Science Strategy

2. Observations

a. Observatories


3. Future works

4. Summary

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A. Road to Super-Novae

http://photojournal.jpl.nasa.gov/archive/PIA09221.mov ; http://upload.wikimedia.org/wikipedia/commons/1/14/Tycho-supernova-xray.jpg

Quiescent

Outburst

Mass Loss ...

Mass Increase ...

Type IaSuper-Novae

？

• WD mass is important !!• Increase or Decrease ... ?• Novae (only CO-type) may be

Type Ia SN progenitors ... ?

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Internal shock with velocity variations

B. Chemical Evolution

• CNe have a large population in the Universe

• An outburst scatters heavy elements

• The composition is derived by X-ray spectra

• A systematic observation of CNe is the key !!

CNe

X-rays from Ejecta

X-ray

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C. Origin of Cosmic-rays

• SNR is a major source of galactic cosmic-rays

• CNe are similar to SNe in many properties

• Accelerated particles are expected ...?

Diffusive Shock Acceleration

DownUp

WaveShock

SNR (SN1006)

http://heasarc.gsfc.nasa.gov/Images/asca/sn1006.gifhttp://vega.ess.sci.osaka-u.ac.jp/info/HE08/HE08/hoshino.ppt; http://www.astro.isas.ac.jp/xjapan/news/article/2004/1209

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Talk Plan

1. Classical Novae

1. Introduction

2. Science Strategy

2. Observations

a. Observatories


3. Future works

4. Summary

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Observations of CNe

1. Discovery by amateur astronomers

- Optical magnitudes and spectra

2. ToO observations with Swift

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Swift

http://imagine.gsfc.nasa.gov/Images/news/swift.jpg

Multi-wavelength observatory （2004, Nov. 20）

High maneuverability

Follow-up observations of unpredictable sources

Burst Alert Telescope （BAT）

X-Ray Telescope （XRT）

UltraViolet and Optical Telescope （UVOT）

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X-Ray Telescope （XRT）

http://swift.gsfc.nasa.gov/docs/swift/about_swift/xrt_desc.htmlhttp://swift.gsfc.nasa.gov/docs/swift/analysis/xrt_swguide_v1_2.pdf

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Example of Swift

Page, K. L., et al. 2009, MNRAS, 1602

Pre-OutburstDay 1～12Day 14～16Day 21～25Day 39Day 53Day 80～109Day 112～168

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Observations of CNe




- X-ray behavior with snapshots

3. Deep spectroscopic study

http://chandra.harvard.edu/graphics/resources/illustrations/chandra_gcenter.jpg

X-ray observatory （1999, Jul. 23）

The third of NASA Great Observatories

Extremely high spatial resolution

CCD Imaging Spectrometer （ACIS-I, ACIS-S）

Transmission Grating （LETG, METG, HETG）

High Resolution Camera （HRC）

Chandra

http://esamultimedia.esa.int/images/Science/XMM1111.jpg

XMM-Newton

X-ray observatory （1999, Dec. 10）

Large effective area

Photon Imaging Camera （EPIC-MOS, EPIC-PN）

Reflection Grating Spectrometer （RGS）

Optical Monitor （OM）

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OVIII

NVII

NVI

Advantages of Grating

Page, K. L., et al. 2009, MNRAS, 1602Ness, J.-W., 2007 (http://xmm.esac.esa.int/external/xmm_science/workshops/2008symposium/ness_ju.pdf)

But, only forbright sources

Swift spectra

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X-ray SatelliteSuzaku （すざく）

http://eda.plain.isas.jaxa.jp/suzaku_xoops/modules/newbb/download.php?url=/Bamba_Bamba_Aya.ppt.1149042392000http://www.isas.jaxa.jp/j/enterp/missions/asca/image/pct_main_asuka.jpg

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Detectors of Suzaku

XRS

(0,1, ,3) (PIN,GSO)

Not-Working...

Bandpass 0.2 ～ 12 keV 15 ～ 600 keV

Spatial Resolution ～2 arcm. (HPD) N/A

Energy Resolution ～130 eV @ 6 keV ～4.0 keV (PIN)

Time Resolution 8 sec 61μsec

2

XIS HXD

Suzaku

http://eda.plain.isas.jaxa.jp/suzaku_xoops/modules/newbb/download.php?url=/Bamba_Bamba_Aya.ppt.1149042392000http://www.astro.isas.jaxa.jp/suzaku/overview/


Point of Views: Suzaku

• Advantages of Suzaku ...- Wide energy range (0.2 ～ 600 keV)- High sensitivity above 10 keV- Moderately good energy resolution

• Suzaku is a well-suited tool ...- To study line emission of hard X-ray- To examine non-thermal emission

We conducted some ToO observationsof classical novae using Suzaku !!

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Observations of CNe




- X-ray behavior with snapshots

3. Deep spectroscopic study

- I will show you the results of Suzaku !!

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Talk Plan

1. Classical Novae

1. Introduction

2. Science Strategy

2. Observations

a. Observatories


3. Future works

4. Summary

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Suzaku View : Classical Novae

ROSAT ALL-Sky X-ray Background Survey (0.73-1.56 keV)http://skyview.gsfc.nasa.gov/cgi-bin/query.pl

Suzaku J0105-72 (2005.08)- Takei et al. (2008), PASJ, 60, S231

V458 Vul (2007.08)- Tsujimoto et al. (2009), PASJ, 61, S69

V2491 Cyg (2008.04)- Takei et al. (2009), ApJL, 697, 54- Takei et al. (2010), AN, 331, 183- Takei et al., in prep.

U Sco (2010.01)- Takei et al., in prep.

V2672 Oph (2009.08)- Takei et al., in prep.

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Discovery of Suzaku J0105-72

Position reconstructed; Outside of the XIS FoV.

Takei et al. 2008, PASJ, 60, S231

Serendipitous discovery of a transient source during a series of routine calibration observations of 1E0102.2-7219.

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Suzaku J0105-72 : Position

X-ray Source

Optical Source (B0)

Error


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Suzaku J0105-72 : Light Curve

x103

Duration is a function of white dwarf mass.

Suzaku (XIS)Decline of the brightness...

Chandra (ACIS)


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Suzaku J0105-72 : Spectrum

WD Atmosphere- OVII Absorption Edge (τ ～ 1.2 )

Small Magellanic Cloud : 60 kpc- Lbol ～ 1037 erg s-1

- RWD ～ 108 cm

Continuum- Blackbody ( kT ～ 72±2 eV )


All these properties indicate that this is a super-soft source.

The temperature and duration are functions of the WD mass.

.- WD Mass ～ 1.2 M。

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Classical Nova V458 Vulpeculae

- Discovery on 2007 August 8.54 (UT)(Nakano et al. 2007, IAUC, 8861, 2)

- Swift detected X-rays on day 70(Ness et al. 2009, AJ, 137, 4160)

http://www.ztv.ne.jp/web/K.Nakajima/image/Nova2007Vul(07.08.09).jpg

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V458 Vul : Light Curve

Tsujimoto et al, 2009, PASJ, 61, S69

Day 88

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V458 Vul : Spectrum

Tsujimoto et al, 2009, PASJ, 61, S69

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Classical Nova V2491 Cygni

- Discovery on 2008 April 10.728 (UT)(Nakano et al. 2008, IAUC, 8934, 1)

- Swift detected X-rays on day 5(Page et al. 2009, MNRAS, submitted.)

- XMM-Newton observed on day 40 and 50(Ness et al. 2009, in prep.; Takei et al. 2009, in prep.)

- X-rays were detected in the pre-nova phase(Ibarra et al. 2009, A&A, 497, L5)

http://www.astroarts.jp/news/2008/04/12nova_cyg/v2491cyg.jpg

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V2491 Cygni : Light Curve

The optical data were provided by the variable star observations from the AAVSOInternational Database and the VSOLJ Observation Database contributed by observers worldwide and used in this research.

Day 9

Day 29

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V2491 Cygni : Spectrum (Day 9)

Takei et al. ,2009, ApJL, 697, 54

The highest energy X-rays up to70 keV ever detected from a nova !!

(Takei et al. 2009, ApJL, 697, 54)

Power-Law

Thin-thermal Plasma

HXD

Energy (keV)

Flu

x (

ph

oto

ns

cm-2

s-1k

eV-1

) XIS

(Γ= 0.1)

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Discussion

Electron

Photon X-ray

-①

MagneticField

Electron

X-ray

-

②

Electron

X-rayProton

-+

③

Non-thermal particle- Theoretical works

(e.g., Tatischeff & Hernanz 2007)

- Radio observations(e.g., Rupen et al. 2008)

Flat power-law spectrum- Photon Index : Γ= 0.1- Flux : I(E) ∝ E-Γ

Electron population- ① IC or ② Synchrotron

-> Number Index : P ≤ -0.8- ③ Bremsstrahlung

-> Number Index : P ≤ 1.1

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• Diffusive Shock Acceleration model (P ≥ 2.0)(e.g., Blandford & Ostriker 1980, ApJ, 237, 793)

• Flat population (P ≤ 1.1) cannot be explained(Takei et al. 2009, ApJL, 697, L54)

Diffusive Shock Acceleration

DownstreamUpstream

WaveShock

SNR (SN1006)

http://heasarc.gsfc.nasa.gov/Images/asca/sn1006.gifhttp://vega.ess.sci.osaka-u.ac.jp/info/HE08/HE08/hoshino.ppt; http://www.astro.isas.ac.jp/xjapan/news/article/2004/1209

Standard Acceleration Model

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Classical Nova V2672 Ophiuchi

http://www.astroarts.jp/news/2009/08/18nova_oph/noph2009_confirm.jpg

- Discovery on 2009 August 16.515 (UT)(Nakano et al. 2008, CBET, 1910, 1)

- Swift detected X-rays on day 1(Schwarz et al. 2009, ATel, 2173, 1)

- Suzaku observed on days 12 and 22(Takei et al., in prep.)

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Day 22

Day 12

V2672 Oph : Light Curve

The optical data were provided by the variable star observations from the AAVSOInternational Database contributed by observers worldwide and used in this research.

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V2672 Oph : X-ray Spectra

Spectral evolution in the flare !!Intensive Si emission line !!

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Talk Plan

1. Classical Novae

1. Introduction

2. Science Strategy

2. Observations

a. Observatories


3. Future works

4. Summary

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Monitor of All-sky X-ray Image (MAXI)

It monitors all-sky the once every 96 minutes

Wide energy range (0.5 ～ 30 keV)

Gas Slit Camera （GSC）

Solid-state Slit Camera （SSC）

1. MAXI

http://cosmic.riken.go.jp/maxi/maxi_public_html/aboutmaxi/JEM_MAXI_with_field_of_view.jpg

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MAXI X-ray Image

http://www.jaxa.jp/press/2009/08/img/20090818_maxi_1L.jpg

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X-ray observatory （planned for launch in 2013）

Future X-ray mission in Japan and US

Soft X-ray Spectrometer （SXS）

Soft X-ray Imager （SXI）

Hard X-ray Imager （HXI）

Soft Gamma-ray Detector （SGD）

2. ASTRO-H

http://astro-h.isas.jaxa.jp/doc/080901_NeXT_SAC1.pdf

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SXS

Detectors of ASTRO-H

Bandpass 0.3 ～ 10 keV 0.5 ～ 12 keV 5 ～ 80 keV10 ～ 600 keV

PSF (FPD) 1.7 arcm. 1.7 arcm. 1.7 arcm. -

Energy Res. ～ 7 eV ～ 150 eV 2 keV 2 keV

Time Res. ? ? ? ?

SXI HXI SGD

http://astro-h.isas.jaxa.jp/doc/080901_NeXT_SAC1.pdf

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Talk Plan

1. Classical Novae

1. Introduction

2. Science Strategy

2. Observations

a. Observatories


3. Future works

4. Summary

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Summary

• Five recent classical novae were observed• WD mass was estimated (Suzaku J0105-72)• Plasma abundances were constrained (V458 Vul)• Non-thermal X-rays were discovered (V2491 Cyg)• X-ray flare was confirmed (V2672 Oph)• Data is coming soon ... (U Sco)• My Ph.D thesis will be bright, like these novae !!!

@ Roof of SAO

x-ray spectroscopy of classical novaedaitakei.com/common/files/presentation_cfa_20100421a.pdfat...

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