supersoft sources in m 31: comparing the xmm-newton deep survey, rosat and chandra catalogues holger...

Supersoft sources in M 31: Supersoft sources in M 31: Comparing the XMM-Newton Comparing the XMM-Newton Deep Survey, ROSAT and Deep Survey, ROSAT and Chandra cataloguesChandra catalogues

Holger Stiele

SuperSoft X-ray Sources – New Developments

ESAC Madrid 20.05.2009

20. May. 2009 Holger Stiele 2

The Large Program CollaborationThe Large Program Collaboration

• PI: W.Pietsch (MPE)

• MPE: V. Burwitz, M. Freyberg, J. Greiner, F. Haberl, H. Stiele

• And: R. Barnard (The Open University), D. Hatzidimitriou (University of Crete), M. Hernanz (CSIC-IEEC), G. Israel (INAF), U. Kolb (The Open University), A. Kong (National Tsing Hua University), P. Plucinsky (Harvard-Smithsonian Centre for Astrophysics), P. Reig (IESL), G. Sala (UPC/IEEC), M. Sasaki (Harvard-Smithsonian Centre for Astrophysics), L. Shaw Greening (The Open University), L. Stella (INAF), B. Williams (Pennsylvania State University)

19 scientists from 7 countries


OutlineOutline

The XMM-Newton Deep Survey catalogue Supersoft sources optical novae

Comparing the XMM-Newton Deep Survey, ROSAT and Chandra catalogues The catalogues The method The results


ImageImage• of Deep survey (“outer ring”)

and archival (“major axis”) data (see Pietsch et al. 2005)

• Fields with high background repeated

• Optical extent indicated by D25 ellipse

•

•

0.2 – 1 keV1 – 2 keV2 – 12 keVSSSs; fgstars + SNRs; hard (AGNs,XRBs,Crab like SNR)

Extended sources mostly background galaxy clusters


Hardness Ratios

i= 1…4

B1: 0.2-0.5 keVB2: 0.5-1.0 keVB3: 1.0-2.0 keVB4: 2.0-4.5 keVB5: 4.5- 12 keV

fg star+ AGNGal/GlC

= X-ray colour

XRB SSS SNR

• Extent

• Time variability

• Cross correlations with optical and radio source catalogues

Further classification methods:

HR2 versus HR1 separate SSS; thermal SNRs and fg stars

SSS


X-ray Sources in M 31 Field: X-ray Sources in M 31 Field: Identification and ClassificationIdentification and Classification

identified classified• SSS 43• SNR 25 38• Globular clusters 36 17• XRB 10 22

• foreground stars 22 243• AGN 3 49• Galaxies 4 21• Galaxy clusters 1 1• Hard 1289• Without 127

1951

+

• SSS 43


Supersoft SourcesSupersoft Sources• Definition:

– Radiation with effective temperature of 10 to 100 eV

– Luminosities: ~1036-39 erg s-1

• HR1 < 0 and HR2 - EHR2 < -0.96 or HR2 not defined, HR3, HR4 not defined

• 43 SSSs, 27 “new”


Flux Distribution

Period 217s Trudolyubov & Priedhorsky 2008

Period 865.5s (Nova?) Osborne et al. 2001M31N2007-06b

M31N2005-01c

7.3 1036 erg/s

Blackbody “model” withTbb = 50 eVNH = 6.61020 cm-2

Unabs. fluxes

erg cm-2 s-1

Num

ber

of s

ourc

esM31N2001-11a

Novae


Optical Novae• Major class of SSSs in

centre of M 31: optical novae (Pietsch et al. 2005, 2007)

• Outer regions: not deep enough optical and no X-ray monitoring for novae/SSSs only snapshots (X-rays) only random detections difficult to determine general properties of disk nova population

2005-01b

1997-10c

2005-09b

2005-01c

2007-06b

1997-10c

SSSsNovae


Optical Novae (II)M31N a. opt.det. Not vis. Distance Tbb (eV) LX (erg/s)

1994-09a 2591 d 3583 d 3.1” 1.61036

1995-11c 1486 d --- 2.1” 1.681037

1996-08b 1880 d --- 1.1” 5.6 1036

1997-08b 1589 d 2514 d 2.3” 0.7 1036

1997-10c 982 d 1167 d 1.9” 41 5.9 1037

1998-06a 1119 d 2235 d 1.1” 1.7 1036

1999-10a 1751 d --- 1.6” 2.121037

2000-07a 170 d --- 1.3” 1.35 1037

2001-10f 84 d 1009 d 0.9” 3.71037

2001-11a 53 d --- 0.5” Smirnova et al. 2006

2005-01b 535 d 1073 d 4.3” 45 1.01037

2005-01c 703 d --- 0.9” 40.23 1.2 1038

2005-09b 299 d 690 d 0.57”

2007-06b See talk of M. Henze Pietsch et al. 2007

35 5.4 1038


Comparing the XMM-Comparing the XMM-Newton Deep Survey, Newton Deep Survey, ROSAT and Chandra ROSAT and Chandra

cataloguescatalogues

XMM-Newton Deep SurveyXMM-Newton Deep Survey• 1951 sources

• 43 Supersoft sources


ROSAT PSPC SurveyROSAT PSPC Survey

• PSPC survey covering the entire galaxy twice 560 X-ray sources Supper et al. 1997, 2001

• Supersoft sources selected from Greiner 2000 and Kahabka 1999: – Similar selection criterion (as used for XMM-Newton)

– Two hardness ratios (based on standard ROSAT energy bands)

– band separation energies at ~ 0.5 keV, and ~ 1 keV

– ROSAT observations taken about > 10 yr earlier than XMM-Newton observations ( investigation of long term variability)


Chandra ObservationsChandra Observations• Observation of selected fields, especially central region

Kong et al. 2002, Kaaret 2002, Di Stefano et al. 2004, Williams et al. 2004, 2006,

• Very soft sources Di Stefano et al. 2004 – Three energy bands: S: 0.1-1.1 keV; M: 1.1-2 keV; H: 2-7 keV Several criteria to select SSSs and QSSs

– Important difference: Contamination of SSS class with

– Temporal distance to XMM-

Only one band below ~1 keV

foreground stars, SNRs and soft AGNs

Newton observations:centre and Field 2: < 1 yrFields 1+3: > ~ 4yr

Image: Di Stefano et al. 2004

Voss & Gilfanov 2007


MethodMethodTwo step process:

First step: Were the XMM-Newton SSSs detected in previous surveys?

XMM – Newton SSS

Full ROSAT PSPC

Full Chandra

Second step: How many ROSAT/Chandra SSSs are detected with XMM-Newton?

ROSAT SSS

Chandra VSS

Full XMM Deep

Survey


XMM-Newton SSS to ROSAT XMM-Newton SSS to ROSAT PSPC SurveysPSPC Surveys

• 43 XMM-Newton SSS, 12 brighter than ROSAT detection threshold (~5.310-15 erg cm-2 s-1):– 2 also found as ROSAT SSSs– 10 not detected with ROSAT: 6 recent novae, 1 transient, 1

variable 2 must be transient/highly variable

• 31 XMM-Newton SSS with fluxes below ROSAT detection threshold: – 1 also found as ROSAT SSSs (~factor 22-25 brighter in

ROSAT observations)– 3 chance coincidences– 27 remaining sources: 7 recent novae, 1 transient (Di Stefano et al.

2004)


XMM-Newton SSS to Chandra XMM-Newton SSS to Chandra SurveysSurveys

• 9 XMM-Newton SSSs have Chandra counterparts:– 6 are also classified as SSSs from Chandra – 8 of the 9 sources are located in the centre of M 31

• 34 sources do not have Chandra counterparts: – 7 are in regions not covered with Chandra– 10 are novae (4 after 2005, 6 no Chandra

detections (see Pietsch et al. 2005, 2007 and M31N1999-10c,

M31N2001-11a))– 1 variable


ROSAT SSSs to XMM-Newton ROSAT SSSs to XMM-Newton Deep SurveyDeep Survey

• 34 ROSAT SSS, 4 not in observed XMM-Newton field• 14 correlations with XMM-Newton sources•

• 16 ROSAT SSS without XMM-Newton counterparts: 1 nova Where are the novae?No systematic search/monitoring campaign in the years before 1990 number of known optical novae very low (see talk of W. Pietsch)

3 SSS confirmed with XMM-Newton

5 Fg Star cand 1 Fg Star

1 SNR 1 Galaxy

2 <hard> 1 No class. (2 XMM)

most of these sources not highly variable (fvar < 5)


Chandra VSSs to XMM-Chandra VSSs to XMM-Newton Deep SurveyNewton Deep Survey

• 20 Chandra SSSs– 15 correlations with XMM-Newton sources:

– 5 not detected with XMM-Newton (4 transients (Di Stefano et al. 2004, 2 of them novae), 1 faint)

5 Confirmed SSSs 2 Fg Star cand.

3 Confirmed fg Stars 1 SNR cand.

2 Confirmed SNRs 2 XRB cnad.


Chandra VSSs to XMM-Chandra VSSs to XMM-Newton Deep SurveyNewton Deep Survey

• 23 Chandra QSSs– 12 correlations with XMM-Newton sources:

– 11 not detected with XMM-Newton (1 outside XMM field, 5 transients (Di Stefano et al. 2004), 1 in crowded centre, 2 faint)

3 Confirmed fg Stars

3 Fg Star cand. 1 Fg Star

1 Bg Gal cand. 2 <hard>

2 No class.


What do we learn?What do we learn?• 3 sources detected in all 3 missions visible

for more than a decade:– Two are located in the central field:

• XMMM31 J004318.8+412017 = r3-8 = [SHL2001] 235: foreground polar? (Williams et al. 2006)

• XMMM31 J004252.5+411540 = r2-12 = [SHL2001] 203 = [PFJ93] 58 = [TF91] 69: 217s period (Trudolyubov et al. 2008)

– XMMM31 J003840.5+401956 = s2-26 = [SHL2001] 27:

r2-12

r3-8

s2-26

ROSAT: ~22-25 brighterXMM: June 2006 – Jan. 2008

in 3 Chandra observations (2000-2001) only once visible

variable (Di Stefano et al. 2004)

ROSAT

ChandraXMM-Newton


What do we learn? (II)What do we learn? (II)

• Of 12 XMM-Newton sources with brightness above ROSAT threshold, only 2 observed by ROSAT underlines variability of the source class on long time scales (~83% variable, cf. Greiner et al. 2004)

• ROSAT as well as Chandra SSSs contain sources of other classes


What do we learn? (III)What do we learn? (III)• Two interesting sources:

– XMMM31 J004307.1+411810 = r3-115: Chandra and XMM-Newton observations between 2000-end 2001: SSSXMM-Newton observation Jan. 2002: hard spectrum (Pietsch et al. 2005)

– XMMM31 J004247.9+411549 = r1-25: Chandra observations between 2000-end 2001: SSSXMM-Newton observation July 2004: hard spectrumoptical counterpart within 1.2” (‘regular or semi-regular red variable’ Fliri et al. 2006)

Nature unclear: X-ray transient (BH primary) or symbiotic

r1-25

r3-115


SummarySummary Deep XMM-Newton survey of M 31 1951 X-ray sources,

43 Supersoft sources Optical novae are an important class of SSSs in M 31 (5 in

addition to Pietsch et al. 2005, 2007) Correlation with ROSAT PSPC surveys and Chandra

catalogues 3 persistent SSSs SSSs are a highly variable source class Many ROSAT and Chandra SSSs get other classes from

XMM-Newton observations Two sources that show supersoft-hard transition between

Chandra and XMM-Newton observations


The large program collaboration:

• PI: W.Pietsch (MPE)

• MPE: V. Burwitz, M. Freyberg, J. Greiner, F. Haberl, H. Stiele

• And: R. Barnard (The Open University), D. Hatzidimitriou (University of Crete), M. Hernanz (CSIC-IEEC), G. Israel (INAF), U. Kolb (The Open University), A. Kong (National Tsing Hua University), P. Plucinsky (Harvard-Smithsonian Centre for Astrophysics), P. Reig (IESL), G. Sala (UPC/IEEC), M. Sasaki (Harvard-Smithsonian Centre for Astrophysics), L. Shaw Greening (The Open University), L. Stella (INAF), B. Williams (Pennsylvania State University)

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