Cairo March 2009

Prospects for Swift studies on NS X-ray binaries

(sorry, no magnetars)

Sergio Campana

Osservatorio astronomico di Brera

• Burst Alert Telescope (BAT)– CdZnTe detectors (7 keV

energy resolution)– 15-150 keV – 1-4’ localization over 2 sr

field of view

• X-Ray Telescope (XRT)– CCD (140 eV @ 6 keV)– 0.3-10 keV– <5” localization over

24’x24’

• (UVOT) UV/Optical Telescope – Imaging & Grism

spectroscopy– UV to V– Sub-arc localization

• Autonomous re-pointing, 60 - 300 sec

• Onboard and ground triggers

BAT

XRT

Spacecraft

UVOT

BAT

UVOT

XRT

Spacecraft

Swift Mission (Nov. 2004 - ...)

How does Swift work?

???

Swift strenghts (I)

Brocksopp et al. 2006

GRO J1655-40

SWIFT J1922.7-1716

Falanga et al. 2007

Multi-wavelength coverage

UVOT

BAT

XRT

XRT INTEGRALRXTE

Swift’s strengths (II)

BAT monitoring of the X-ray sky (about 100 sources detected daily). BAT is able to discover new X-ray transient and follow them during the brightest part of the outburst. Daily 1 ks observation of the Galactic Center.

1600 s

Krim

m e

t al.

2006

Galactic Center region

Swift’s strengths (III)Thanks to its scheduling flexibility (one shot) ideal instrument to perform short exposures to identify and to provide an accurate localization of hard X-ray sources (e.g. INTEGRAL, RXTE, Swift-BAT) as well as past and present X-ray missions (RASS, ASCA and XMMSL).

Leyder et al. 2007

Sguera et al. 2007

IGR J18483-0311

INTEGRALROSATSwift-XRT

ISGRI, JEM-XSwift-XRT

IGR J08408-4503

Swift’s strengths (IV)

Thanks to its scheduling flexibility (multiple shots) ideal instrument to perform (loose) monitoring campaigns.

Campana 2009

23 d

RXS J171824.2-402934

Swift NS-binaries science

Strange transients

Wijnands et al. 2009 Consistent with a type I burst from a LMXRB

10 d

Accreting ms X-ray pulsars

Discovery of the seventh AMXPs SWIFT 1756.9-2508

Krimm et al. 2008

X-ray transients (AMXP)

Campana et al. 2008

SAX J1808.4-3658

X-ray transients (classical)

Degenaar et al. 2009

unpublished

EXO 0748-676

Aql X-1

Monitoring of the Galactic center

Degenaar & Wijnands 2009

Fast transientsRomano et al. 2007IGR J11215-5952

INTEGRALRomano et al. 2008

P~164.6dP~164.6d

Eccentric orbitEccentric orbit

Fast transients (II)

Sidoli et al. 2008

Summary

Swift thanks to:

• Wide energy range UV to hard X

• Flexibility

• Sensitivity (especially for binaries and AXP that are bright objects)

Can in the next few years provide important results in this field

• Detecting (new/rare transient sources, bursts, superbursts)

• Monitoring (evolution of outbursts, long term spectral changes, timing)

• Archiving (long term light curves)

Swift in perspective

• Monitor X-ray binary transients’ state changes, launch of micro-jet and jets (BAT, XRT, UVOT)

• X-ray burst statistics (BAT)

• Detect in real time and follow superbursts (BAT & XRT follow-up)

•Follow fast transient outbursts (XRT)

• Follow transient outbursts down to quiescence (BAT, XRT & UVOT)

X-ray burst studies & statistics

Burst rate as a function of flux

Cor

nelis

se e

t al.

2003

Coc

chi e

t al.

2001

Gal

low

ay e

t al.

2004

Eddington-limited burst

Periodic behaviour as a function of flux

SuperburstsIn

’t Z

and

et a

l. 20

04

Str

ohm

ayer

&

Mar

kwar

dt 2

002

4U 1636-53

State transitions

Belloni 2007

BH XRB

NS XRB

Homan et al. 2007

X-ray transients

Aql X-1SAX J1808.4-3658

Campana et al. 2007a

Campana et al. 1998

20022006

mC

rab