A catalogue of X-ray emitting WR stars Ada Nebot, C. Motch, and the - - PowerPoint PPT Presentation

A catalogue of X-ray emitting WR stars

Ada Nebot, C. Motch, and the ARCHES collaboration

ARCHES workshop Paris, 30 Novembre - 2 Dicembre 2015

The Galactic science case

• What is the XLF of the hard X-ray

low to intermediate luminosity sources?

• CVs, AB (Sazonov+2006)
• OB, WR too!! (Mauerhan+2010,

Anderson+2011)

• What is the origin of the hard X-ray

emission in O,B and WRs?

• Intrinsic X-ray emission
• Wind accretion onto a compact
• bject
• Colliding winds in a binary

How can XMM-Newton help?

• Large FOV ~30 min + high sensitivity
• 30-100 serendipitous sources/pointing

~133.000 sources with multi-wavelength information

EPIC-pn 0.2-12 keV image of field 3C436

• Statistical identification based on

different surveys:

• Bright flux sample Della Ceca+2004
• Medium flux sample Barcons+2002
• Faint flux sample
• Galactic Plane Survey Hands+2004, Motch

+2010, Nebot Gómez-Morán+2013

The cross-correlation

2MASS EPIC-pn DSS GLIMPSE AllWISE

Cross-correlation with

• ptical/infrared catalogues

2MASS

WO 1% WC 43% WN 57%

Wolf-Rayet stars

• The input catalogue: 639 WRs from the catalogue from P

. Crowther

WO 1% WC 39% WN 60% WO 1% WC 43% WN 57%

Wolf-Rayet stars

• The input catalogue: 639 WRs from the catalogue from P

. Crowther

• The coverage: ~one third within the ARCHES catalogue coverage

WO 7% WC 21% WN 72%

• The input catalogue: 639 WRs from the catalogue from P

. Crowther

• The coverage: ~one third within the ARCHES catalogue coverage
• The detections: 29 WRs with an entry in the ARCHES catalogue

WO 1% WC 39% WN 60% WO 1% WC 43% WN 57%

Wolf-Rayet stars

• What is the fraction of active WRs ? Does it depend on the spectral type?
• ~17% of the WN (mostly binaries but some single too)
• ~8% of the WC (binaries + the single ? WR102-1)
• 100% WO (WR 30a binary, WR142 is likely single fast rotator)

Wolf-Rayet stars: fraction of X-ray active WRs

• But need to correct for detection biases:

f = # WRs detected / # WRs covered x detection biases

• Detection biases depend on: Lx, Nh, distance, exposure time, sensitivity,

… (work in progress)

Using WR as learning sample…

0.5 1.0 1.5 2.0 2.5 H-Ks

• 0.5

0.5 1.0 HR3 1: WR

X-ray and infrared colours

• (H-K) estimate on the

extinction AK Indebetouw et

• al. (2005)
• Modelled the evolution of HR

with extinction for different populations:

• Young stars (dashed line)

(kT1,kT2) = (0.2,0.8)keV

• Hard WR (solid line)

kT = 5 keV (e. g. WR 142, Oskinova et al. 2009)

Using WR as learning sample…

0.5 1.0 1.5 2.0 2.5 H-Ks

• 0.5

0.5 1.0 HR3 1: WR

Soft Hard

• (H-K) estimate on the

extinction AK Indebetouw et

• al. (2005)
• Modelled the evolution of HR

with extinction for different populations:

• Young stars (dashed line)

(kT1,kT2) = (0.2,0.8)keV

• Hard WR (solid line)

kT = 5 keV (e. g. WR 142, Oskinova et al. 2009)

Using WR as learning sample… X-ray and infrared colours

0.5 1.0 1.5 2.0 2.5 H-Ks

• 0.5

0.5 1.0 HR3 Hard X-ray 1: WR

What is the nature of the hard X-ray sources with infrared (2MASS & GLIMPSE) associations?

Soft Hard

X-ray and infrared colours Using WR as learning sample…

0.5 1.0 1.5 2.0 2.5 H-Ks

• 0.5

0.5 1.0 HR3 Hard X-ray 1: WR 7: HMXB 7: Be

What is the nature of the hard X-ray sources with infrared (2MASS & GLIMPSE) associations?

Soft Hard

Using WR as learning sample… X-ray and infrared colours

0.5 1.0 1.5 2.0 2.5 H-Ks

• 0.5

0.5 1.0 HR3 Hard X-ray 1: WR 7: HMXB 7: Be

Pilot Survey: Awarded 1/2 night at the WHT What is the nature of the hard X-ray sources with infrared (2MASS & GLIMPSE) associations?

Soft Hard

Using WR as learning sample… X-ray and infrared colours

Nebot Gómez-Morán et al 2015 (astro-ph XXX) 0.2-12 keV, XMM 8 µm, GLIMPSE 24 µm, MIPSGAL 0.2-12 keV, XMM 5.6 µm, GLIMPSE 1.4 GHz, VLA 0.2-12 keV, XMM 24 µm, MIPSGAL 1.4 GHz, VLA 0.2-12 keV, XMM 8 µm, GLIMPSE 24 µm, MIPSGAL 0.2-12 keV, XMM 8 µm, GLIMPSE 24 µm, MIPSGAL

WN8h Ofpe/WN9 Be

Investigating multi-wavelength properties…

X-ray-to-infrared flux ratio

log (fx/fk) < -2 — WR log (fx/fk) ~ -2.5 — γ-Cas analogs log (fx/fk) > -3 — HMXBs What is the nature of the hard X-ray sources with infrared (2MASS & GLIMPSE) associations?

Nebot Gómez-Morán et al 2015

• 5
• 4
• 3
• 2
• 1

log10(fx/fk) 2 4 6 8 1 0 1 2 1 4 Ks Unidentified Be HMXB W R

γ-Cas

Investigating multi-wavelength properties…

Lx versus Period

141 139 138 133 4 7 4 6

• 1

1 2 3 4 log (Period [days]) 32.0 32.5 33.0 33.5 34.0 Lx (0.2-12keV) [ergs/s]

a WN

Preliminary results… Distance known for 24 of these 31 WRs, and period for 12 binaries Computed mean Lx in three bands: T

• tal (0.2-12 keV), soft (0.2-2 keV), hard (2-12keV)

Lx in 0.2-12 keV

Lx versus Period

30a 140 7 9 4 8 1 1 141 139 138 133 4 7 4 6

• 1

1 2 3 4 log (Period [days]) 32.0 32.5 33.0 33.5 34.0 Lx (0.2-12keV) [ergs/s]

a WO a WC a WN

Lx in 0.2-12 keV Preliminary results… Distance known for 24 of these 31 WRs, and period for 12 binaries Computed mean Lx in three bands: T

• tal (0.2-12 keV), soft (0.2-2 keV), hard (2-12keV)

30a 140 7 9 4 8 1 1 141 139 138 133 4 7 4 6

• 1

1 2 3 4 log (Period [days]) 32.0 32.5 33.0 33.5 34.0 Lx (2-12keV) [ergs/s]

a WO a WC a WN 30a 140 7 9 4 8 1 1 141 139 138 133 4 7 4 6

• 1

1 2 3 4 log (Period [days]) 31.0 31.5 32.0 32.5 Lx (0.2-2keV) [ergs/s]

a WO a WC a WN

2-12 keV

Lx versus Period

0.2-2 keV Preliminary results… Distance known for 24 of these 31 WRs, and period for 12 binaries Computed mean Lx in three bands: T

• tal (0.2-12 keV), soft (0.2-2 keV), hard (2-12keV)

Summary

• The WR catalogue will provide SED for at least 31 WRs (WN, WC and

WO) detected in X-rays.

• Hard X-ray sources with log(fx/fk) < -3 are dominated by WR stars
• We have WR candidates and we plan to take more spectra to confirm

their nature.

• and…