XMM-Newtonsurvey of theSMC: Thepoint source catalog

R. Sturm1, F. Haberl1, W. Pietsch1, M. Coe2, S. Mereghetti3, N. LaPalombara3, A. Tiengo3, M. Ehle4, M. Gil fanov5,M. Fili povic6, D. Hatzidimitriou7, R. Corbet8,9, D. Bomans10, S. Snowden9, J. Ballet11, R. Owen11, D. Buckley12

1Max-Planck-Institut fur extraterrestrischePhysik, P.O. Box 1312, D-85741Garching, Germany (rsturm@mpe.mpg.de); 2School of PhysicsandAstronomy, University of Southampton;3INAF, Istituto di AstrofisicaSpazialeeFisicaCosmicaMilano;4XMM-Newton ScienceOperationsCentre, ESAC,

ESA;5Max-Planck-Institut fur Astrophysik;SpaceResearch Institute, Russian Academy of Sciences;6University of Western Sydney;7Department of Astrophysics, Astronomy andMechanics, Faculty of Physics, University of Athens; Foundation for Research andTechnology Hellas, IESL;8University of

Maryland;9NASA/Goddard SpaceFlight Center;10Astronomisches Institut der Ruhr-UniversitaBochum;11LaboratoireAIM, CEA-IRFU/CNRS/UniversiteParis Diderot;12South African Astronomical Observatory.

Summary

The XMM-Newton large-program survey of the Small Magellanic Cloud (SMC) [1,2] in combinationwith archival observations, reveals more than 3000sources [3] in a field of 5.7 deg2 covering the SMCmain body(the bar and eastern wing). This is a significant improvement compared to the 70 sourcesdetected byEinstein in the1980sand 563 byROSAT in the1990s. TheSMC offersauniquepossibilit y toinvestigate theX-ray sourcepopulation of agalaxy aswhole. Thesmall distanceof ∼60 kpc andthe lowGalactic foregroundabsorption of the SMC enables us to study complete X-ray sourcepopulations, likesupernova remnants (SNRs), high massX-ray binaries (HMXBs) and super soft X-ray sources (SSSs)in a low metalli city environment. This is contrary to the Galaxy, where most sources are obscured bylarge amounts of absorbing gas and where uncertainties in distances complicate the determination ofluminosities, or to more distant galaxies, where spatial confusion of individual X-ray sources becomescomplicated and only thebrightest X-ray sourcescan bedetected (e.g. for M31, LX &10

35 erg s−1).

TheData

SMC survey data33 observations (1100 ks)

Archival data34 observations (750 ks)

Calibration observations28 observations (850 ks)

N

E20’ 0 2.5 ks 12 ks 50 ks 200 ks 800 ks

20’

N

E

Left: Hα imageof theSMC overploted with observed fields. Credit: F. Winkler/Middlebury College, theMCELS Team, andNOAO/AURA/NSF

Right: Combined EPIC exposuremap. EPIC MOSis wighted by 0.4 to account for thesmaller effective area.

XMM-NewtonEPIC colour imageof theSMC

20’

N

E

ThemosaicEPICcolour imageof theSMCrevealsmore

than 3000 point sources. In addition several supernova

remnants, clusters of galaxies, and diffuse emission is

seen. In the zoom-in ontheright, detected point sources

are marked by blue circles and pulsars and SNRs are

labelled in white. The moon demonstrates the size of

thefield.

(0.2–1.0) keV

(1.0–2.0) keV

(2.0–4.5) keV

Zoom, see right

Sourcedetection

new cand

new cand

J0047-7306

15.3s

172s

323.2s

755.5s

894s

?

?

?

25.55s

11.87s

263s

HFPK 419

DEM S32IKT2

IKT6

IKT4

IKT5

5’

Source classification

We used X-ray hardness ratiosand information from other wave-lengths, e.g. the flux ratio fX/fopt,to classify sources [4].

Class identified classified

HMXB 55 27SSS 4 7AGN 46 1771fg-star 3 93

HMXB are remarkably frequent in theSMC [5,6]. Thesurveyenables us to studya completepopulation. HMXB can beused toestimate thestar formation rate [7].

SSS are explained by thermonuclear burning onthesurfaceof awhitedwarf. The low foregroundabsorptionenables thestudy ofthesesources in theSMC.

AGN behind theSMC provide areferenceframe for propermotionstudies andmight beused to probe the absorption bytheinterstellar medium of theSMC.

Examples for data analysesof individual sources

0.1

1

Cou

nts

s−1

keV

−1

0.2 0.5−4

−2

0

2

χ

Channel energy (keV)

2006 Mar2007 Apr2007 Oct2009 Oct

0 0.05 0.1 0.15 0.2 0.25

020

4060

Pow

er

Frequency (Hz)

0.951.001.051.101.15

0.2-

1.0

keV

0.9

1.0

1.1

1.2

1.0-

2.0

keV

0.91.01.11.2

2.0-

4.5

keV

0.900.951.001.051.10

4.5-

10.0

keV

0.0 0.5 1.0 1.5 2.0Phase (11.86642 s)

0.900.951.001.051.101.15

0.2-

10.0

keV

Examples for different types of sourceproducts. Left: Spectral analysis of thesymbiotic novaSMC3at 4 different epochs[8]. Middle: Long-term X-ray light curve(lower panel) of a new discovered SSScompared with the I-band light curve ofthe optical counterpart from OGLE III [9].Right: Power density spectrum and foldedpulse profile of the new discovered Be/X-ray binary pulsar with 11.86642(17) s spinperiod [10].

Catalogcharacterisation

5236 detections of 3053individual X-ray sources

927sourcesaredetected more than once

Somesourcesaredetected upto 34times

∼ 500 detections havesufficient statistics for detailed spectraland timinganalysis

positionaccuracy: 1.42′′

(usingastrometric correction)

6433 upper limits for non-detections

exposure: ∼10–30 ks (average), ∼600 ks (maximum)

complete to 10−14 erg s−1 cm−2 in the (0.2–4.5) keV band

corresponding to 4.3×1033 erg s−1 for theSMC

General characteristicsof thedataset

−1 −0.5 0 0.5 1−1

−0.

50

0.5

1

HR

3

HR2

HMXBHMXB?AGNAGN?fg−starfg−star?other

10−15 10−14 10−13 10−12 10−11 10−10

110

100

1000

V =

Fm

ax/F

min

Fmax (erg cm−2 s −1)

HMXBHMXB?AGNAGN?SSSSSS?fg−starfg−star?other

Left: Hardnessratio diagaram. Right: Long-term timevariabilit y.

References[1] Haberl & Pietsch 2008, in X-raysFrom Nearby Galaxies[2] Haberl et al. 2011, in preperation[3] Sturm et al. 2011, in preperation[4] Pietsch et al. 2004, A&A 426, 11[5] Haberl et al. 2008, A&A 489, 327[6] Coe2005, MNRAS 358, 1379[7] Antoniouet al. 2010, ApJ716L,140[8] Sturm et al. 2011, A&A 529, 152[9] Sturm et al. 2011, in preperation[10] Sturm et al. 2011, A&A 527, 131

The X-ray Universe 2011, Berlin, Germany, 27-30 June 2011