andrea santangelo, iaat bologna 15.05.2007simbol-x workshop “broad band continuum and cyclotron...

Bologna 15.05.2007 Simbol-X Workshop Andrea Santangelo,IAAT

“Broad Band continuum and Cyclotron Scattering Features in the Spectra of

Accreting X-ray Pulsars”

Andrea Santangelo, E. Kendziorra, C. Tenzer, D. Klochkov, D. Horns, T. Schanz, M. Martin

Institut für Astronomie und AstrophysikKepler Center for Astro and Particle Physics

Karls Eberhard Universität Tübingen


Courtesy of Scientific American X-ray Binaries with a NS

Liu et al. A&A, 2000, 2005

G10B 12

Most of them are in HMXRB

A few LMXRB (Her X-1, 4U1626-67,

GX1+4)


Accretion

Kuster, 2003

Ghosh & Lamb, 1978

B ~ 1012-1013 GOn grounds of magnetic flux conservation during the SN core collapse


The „Transient“ Behaviour of the Be/X-ray Binaries

Kretschmar, 1996

1 Crab1mCrab


Accretion Columns ? Basko & Sunyaev, 1976

Kuster, 2003


Or Accretion “Spaghetti” ?


Kretschmar, 1996 after Harding, 1994

erg/sec 1037L


BB

Fe Lines

PL ~

Ecyc

Wien Hump

Dal Fiume et al., A&A 1998


POHEI (E) =E E<Ecut

E>EcutEexp(-(E-Ecut)/Ef))

)EEE

exp(1

1)E(FDCO

cut

kTE

22kTE

21 e))E(oE(e)EAEA(NPEX 21

White et al, 1983

Tanaka, 1986Mihara, 1995

Approximates thermal comptonization Sunyaev and Titarchuk, 1980

The continua ?

Segreto, 2001


1st Science Question• Which is the broad band continuum of accreting Pulsar ?• What are the physical processes that generates the continuum

emission in the accretion column? And the ones that reprocess the emerging radiation ?

Becker & Wolff, ApJ 2007


Broad Band Phase Resolved Spectroscopy with high granularity in phase

1st Requirement


Cyclotron lines basic theory

γmc

eBωc

Gauss 12

10 of units in B keVB6.11E 12c,e cn ωnω

The motion of the electron perpendicularly to the B field is quantized in the Landau levels

Equispaced

If relativistic corrections are taken into account z1

1

θsin

1θsinBBn2mc

mcω 2

2

crit

2

2n

θ is the angle between the photon and the magnetic field

G1014.4e

cmB 13

32

cr


Cyclotron lines basic theory (2)

Electron is excited to the n Landau level

Lifetime is short

De-excitation to ground state via single or multiple photon emission

Mean free path is short, quasi instantaneous re-capturing of the photon

Bologna 15.05.2007 Simbol-X Workshop Andrea Santangelo,IAATSchönerr et al., PHD Thesis, 2007


1:(1.9±0.05):(2.8±0.05):(3.9±0.1)

Harmonic ratios

The EW of harmonics were found to be larger than the fundamental

Shallow First

Deep Second

RXTE Heindl et al. 1999; BeppoSAX Santangelo et al., 1999

E1cyc 12.74

E2cyc 24.16

keV

E3cyc 35.74

E4cyc 49.5

keV

E5cyc 60. keV


2nd Science Question• What can we learn from phase resolved studies of

Cyclotron line energy, width and depth? • Can we extract Physical information (Physical

parameters of the plasma!) from the phase variation of the line shape and emission wings ?

• Excellent progress have been made in the last years!!

G. Schönherr et al., A&A, submitted

O. Nishimura, PASJ, 2006

Araya & Harding, ApJ 517, 334 (1999)

Araya & Harding, ApJ 544, 1067 (2000)


f(θ)

f(E) f(p)

• energy distribution ~ f(E)

• isotropic injection

• internally irradiated plasma

• electron temperature Te

• rel. Maxwellian distribution

• ground Landau state

• low-density plasma

Ingredients: geometry, photons and electrons

B~1013G

cylinderτcy = τ/sin(θ)

θ

<σ(E,θ)>f(p,Te)

QM relativistic cross sections

E┴

Courtesy of Gabi Schönherr, IAAT/Bamberg; Schönherr et al., 2005

Schönerr et al., PHD Thesis, 2007


Line morphologySchönerr et al., A&A submitted 2007


Phase Resolved Spectroscopy of harmonics parameters and capability of

morphological studies

2nd Requirement


The luminosity dependence

? H

MM col

? MH Anticorrelation ?

Correlation ?


Correlation or Anti-correlation?

Tsygankov et al., 2006 V0332+53, Outburst 2005 Anticorrelation is clearly observed

Staubert et al., 2007 Her X-1, 5 years of data Correlation is clearly observed

Caballero et al., 2007 A0535+26


Again X0115+63

Tsygankov et al., 2007, astro-ph 0704.2874v1 4U 0115+63, Outburst 1999, but also 2004


3rd Science Question

• What can we learn from the luminosity dependence of Cyclotron line energy, width and depth ?

• Correlation/Anticorrelation are related to the accretion luminosity ? Do we observe a change of regime around 1037 ergs/sec ?


Capability of monitoring with good accuracy and wide dynamic range the

luminosity dependence of CRSF parameters

3rd Requirement


Simbol X: broad band

seck1

)08.0(04.067.0Depth

)0.3(3.04.7

)2.1(6.05.38E0


Simbol X: Phase Resolved Spectroscopy


Simbol X: Morphology

seck3


Luminosity dependence, V0332

%2Depth

%1

%1E0

%3Depth

%8

%1E0


Conclusions• Simbol X will be able to observe with unprecedented accuracy

– Broad band phase resolved continuum (BB, PL, Cut-off, harder tails)

– The Phase Dependence of CRSF – The Luminosity dependence of CRSF parameters– Phase Resolved Line shapes studies

Emission processes of spectral formation …spectral reprocessing

Geometry of the pulsed components …of the line forming region

Plasma Parameters …B, T, tau, etc…

andrea santangelo, iaat bologna 15.05.2007simbol-x workshop “broad band continuum and cyclotron...

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