EPIC - Palermo (14-16/10/03) 1

X-rays from star-forming regions :Stellar and Interstellar Studies

with XMM (and Chandra)

Thierry Montmerle (Grenoble)with : Nicolas Grosso & Hideki Ozawa (Grenoble)Myha Vuong (Saclay), Eric Feigelson (Penn State)

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Outline

• 1. Nearby star formation in clusters : – Introduction : case of the Oph cloud

• 2. EPIC results : Stellar studies – data analysis – comparison with Chandra

• 3. Interstellar studies : Metallicity of nearby star-forming clouds using X-ray absorption

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1. Introduction

Looking towards and through

molecular clouds

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The Oph cloud core in X-rays : Chandra (5+100 ksec) + XMM (25 ksec) fields

Chandra ACIS

XMM EPIC

ISOCAM

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10 m 1 m

IR

optical

UV

dust gas+dust

X

EUV

1 surface

10 medium

100 core

~ EX–2.5

0.1 keV 1 keV 10 keV

XMM/Chandra

AV(X=1)

2 m 2 keV™

Cloud

Lyman disc.

x 107

Röntgen, 1895

CN

O

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2. XMM/EPICobservations of the Oph cloud

Comparison with Chandra

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The XMM view of the Oph cloud core(Grosso, Ozawa, Montmerle et al. 2003)

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Cross-Identification of MOS1, MOS2, and PN sources

3 + 1” ⇒ same source

Several “binary” sources → caused by alignment ?

MOS1 MOS2 PN

A○ × out

× ○ out

B○ × out

× ○ out

C○ × ×

× ○ ○

D○ × ×

× ○ ○

E○ ○ ×

× × ○

F○ × ×

× ○ ×

G○ ○ ×

× × ○

H○ × ○

× ○ ×

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Identification between MOS1

and 2MASS

DETX (“)

DETY(“) rotation N

1 -0.6 -0.4 -1.5e-3 25

2 -0.8 -0.8 -1.2e-3 2

3 -2.2 0.6 7.4e-3 3

4 -1.2 -0.7 -3.6e-3 4

5 -0.7 -0.6 2.8e-3 4

6 -2.4 -3.1 1.2e-3 8

7 -3.2 1.0 -9.4e-3 3

3 + 1” ⇒ same source

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DETX (“) DETY(“) rotation N

1 0.3 -1.4 -0.6e-3 21

2 -1.2 -1.0 -3.8e-3 12

3 0.7 -1.9 0.4e-3 4

4 -0.8 0.1 3.7e-3 3

5 2.0 -2.7 -1.1e-3 3

6 -0.2 -2.5 4.5e-3 7

7 0.7 -1.3 1.9e-3 3

Identification between MOS2

and 2MASS

3 + 1” ⇒ same source

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DETX (“) DETY(“) rotation N

all -0.2 -0.1 -0.2e-3 57

Identification between PN and

2MASS

3 + 1” ⇒ same source

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Before correction After correction

Position correction of the EPIC images

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Before correction After correction

Position correction of the EPIC images

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XMM-Newton

Chandra

Number of sources

87 87

Number of sources in both F.O.V

47 81

Detection by both

43 43

F.O.V~30` diameter

17`x17`

Time 30 ks 100 ks

(Chandra data from Imanishi et al. 2001)

Source detection and Identification

with Chandra X-ray sources

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Identification with Infrared

YSOs

Class I : 7/11(protostars : envelopes)

Class II : 28/61(T Tauri stars with disks)

Class III : 14/15(diskless T Tauri stars)

Classification by Bontemps et al. 2001

X-ray detection rate

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Lx vs. Lbol

Weak correlation between Lbol and LX index : 0.11

LX/Lbol is not constant with Lbol

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3. Looking through the Oph cloud

First measurement of the metallicity

of a molecular cloud(Vuong et al. 2003)

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IR sources

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X-rays (> 100 cts) => NH,X NIR to MIR => AJ

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NH,X : Cross-check between Chandra and XMM (3 sources)

[~107 K]

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Galactic relationX-ray counts

?

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NH,X <=>Metallicityfrom X-rayabsorption

AJ => AV via RV

<=> grain properties

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Conclusions(among others)

• The wide FOV of XMM/EPIC allows to capture the essence of high-energy star formation in one single exposure; links with IR however necessary to understand the nature of the sources

• => X-ray properties evolve significantly from protostars (envelopes) to “old” T Tauri stars (without disk)

• Spectral properties (absorption up to very high values) may be used to probe the metallicity of molecular clouds -a specific property of X-rays