The Suzaku PV observation of the Planetary Nebula BD+30°3639

The Suzaku PV observation of the Planetary Nebula BD+30°363

9Mio MURASHIMA, Motohide KOKUBUN (U-Tokyo),

Hiroshi MURAKAMI (ISAS), Kiyoshi HAYASHIDA (Osaka-U), Kyoko MATSUSHITA (Tokyo-U.Sci), Jun'ichi KOTOKU (Titech),

Keith ARNAUD, Kenji HAMAGUCHI (GSFC),Kazuo MAKISHIMMA (U-Tokyo/RIKEN)

Mostly based on the PhD Thesis by Mio Murashima“X-ray Study of Planetary Nebulae”

Nov. 2005: Approved by SWG to use the Suzaku data, on condition that the results be published by the end of March.

Dec. 20, 2005: Thesis submitted to Dept. Astronomy, U.Tokyo.

Jan. 26, 2006: Thesis defense completed successfully. Feb. 14, 2006: Thesis accepted. March, 2006: Degree to be awarded.

To be submitted to ApJL as Murashima et al.

1. Contributed to R&D and pre-launch tests of the HXD.2. Explored X-ray emission from pl. nebulae (with Dr. Kokubun).3. Proposed and planned the PV observation of BD+30 3639 (acce

pted on Sept. 10, 2005).4. Contributed to quantification of the XIS low-E QE change (on xoo

ps).5. Lead data analysis, and discovered a very high C/O ratio.6. Accomplished a fine PhD thesis in only half a year after the laun

ch (perhaps the quickest record among Japanese astro-satellites).

7. Her results selected as one of three press-release topics at the JAS meeting in March 2006.

8. Presently, serving as a duty scientist at USC.

1. Qualification of Mio Murashima(Guideline set by the Steering Comm. on Jan. 13, 2006)

Feb.20, 2006 Suzaku SWG 3/25

BD+30°3639 / HD184738 / V1966 Cyg One of the most well studied planetary nebulae (PNe) (α,δ)=(19 34 45.23, +30 30 58.9) ; (l,b)= (64.79, +5.

02) Distance 1.3±0.2 kpc NH ~ 1e21 cm-2

2. The target

color: H-alphacontours: X-ray

2.5 arcsec The X-ray brightest PN. X-rays are emitted from inside

the optical shell. Similar shapes in C- and O-bands.

(2-1) Basic information

0.3–0.5 keV 0.5–0.7 keV


(2-2) Previous X-ray spectroscopy

Newton

Chandra

XIS-BI XIS-FI

Responses to 0.37 keV monoenergetic X-rays

ASCAArnaud et al. (1996)

ChandraKastner et al. (2000)Mannes et al. (2003)

0.5 1.0 1.5 keV

Ne (H)

C N O

C N O Ne

ASCA354 <35 <3

10.5 +7.7-4.5

Chan-dra 354 9 4.2

19.3 ±1.4

Extreme abundances suggested

assumed


3. The Suzaku Observation PV-phase observation on 2005 September 21-22 Exposure 34.3 ks 0.033 c/s/XIS-FI, 0.089 c/s/XIS1

SDSS optical imageGray scale: [OIII]Contours: X-rays(ROSAT)Mavromatakis et al. (2002)

SNR G65.2+5.7

18 arcmin 1 deg.

XIS field of view


source region bkgd region

5. The XIS Images

XIS-0 (0.3-0.7 keV) XIS-1 (0.3–0.7 keV)

XIS-1: 0.3–0.5 keV

XIS-1: 0.5–0.7 keV


6. Analysis of the XIS Spectra(6-1) Raw XIS-1 spectra

kT=0.2 keV 1 solar

[H-like C] / [He-like O] line ratio

Decreasing relative QE

× 0.75

XIS-BI response (initial) × 0.5

Inter-Stellar NH (1e21)

× 0.4

~0.3

Expected count ratio : ~0.02

Excess NH (1e21) × 0.4

The observed C lines are much stronger!

source region,background region

H-like O-Kα0.65 keV

He-like O-Kα0.56 keV

C-Kβ (0.44 keV)

H-like C-Kα (0.37 keV)

He-like Ne-Kα0.91 keV


XIS-1XIS-023

Before correction

XIS gain: self-calibrated (2-3 %) using lines in the source spectraLow-E QE: calibrated using RXJ 1856.5-3754 (2005 Oct. 24).

XIS-1XIS-023

After correction

Energy dependence of excess absorption ⇒ modeled so that the XIS spectra of RXJ 1856 can be reproduced by the XMM-determined blackbody model.

Time evolution of the excess absorption ⇒ modeled so that the Chandra flux of BD+30 3639 agrees with that with Suzaku.

QE decrease from the launch at 0.37 keV is ~54% on Sept. 21, and ~30% on Oct. 24.

(6-2) The XIS low-energy CAL (on xoops)

XMM model


APEC, NH=1x1021 cm-2

1.5

CVI OVIIOVIII NeIX

0.3 0.5 1.0 2.0

Energy (keV)

(6-3) Simple model fits to the XIS-1 spectrum

Fixed at 1 solar abundance⇒ kT ~ 0.24 keV (χ2/dof = 648/79)

0.3 0.5 1.0 2.0

Energy (keV) Fiexed at solar ratios⇒ kT ~ 0.23 keV, ab.~ 0.01 solar (χ2/dof = 296/78)The spectrum cannot be reproduced by isother

mal solar-ratio IE models.


(6-4) 1T analysis vAPEC, ACIS/XIS-1/XIS-023 joint

0.3 0.5 1.0 1.5

Energy (keV)

ACISXIS-1

XIS-023

Absolute abundances are highly uncertain because;- He/H ratio can be non-unity- Metals themselves emit continuum

NH = (2.1+0.2–0.4) e21

kT = 0.19 ± 0.01 　keVC = 19+43 -11

N = 0.67+0.25 -0.20 O = 0.20+0.03 -0.02

Ne = 1.1+0.2 -0.1

Fe < 0.07Others = 0 fixedχ2/dof = 312/229


Confidence contours68%, 90%, 99%

Abund. (solar)

90% range

C/O 95 75-110

N/O 3.3 1.0-5.0

Ne/O 5.5 4.8-7.3

Abundance ratios are well dtermined.

C/O N/O

Ne/O

(6-5) 1T abundance ratios

Lower-kT plasmas would emit stronger C-lines. What if there are mutiple kT’s (but with the same abundances)? Test 2T-model fits (free kT’s and free norms), but asuuming the C/O ratio.

0

10

20

30

40

50

60

10 100

del

ta-c

his

qu

are

assumed C/O ratio10 20 30 50 100 200

Assumed C/O ratio

(6-6) 2T analysis

010203040506010100delta-chisquareassumed C/O ratio

1T: C/O = 75~110

0.3 0.5 1.0 2.0

Energy (keV)

2T: C/O = 35~120

ACIS

XIS-1

XIS-023

ACIS

XIS-1

XIS-023

The high C/O ratio remains unchanged even considering muti-kT condition.


7. Interpretation

Fast wid（ 700 km/s ）

Central star

Hot gas

Shell (nebula)

Contact discontinuity

Inner shock

Outer shock

Interpretable in temrs of Interacting Stellar Wind model (Kwok et al. 1978; Volk & Kwok 1985)

C/O ~ 60 (solar units)

14N(α,γ)18F(β+ν)18O(α,γ)22Ne

Typical in the He-burning layer; competition between 3α reaction and 12C(α,γ)16O (Suda et al. 2004)

H-rich env.

Masss loss

conduciton

convection

He-burning shell

X-ray emission (size, kT,,..)

Lx~ ~ 1.4×1033 erg s-1

only ~0.1% of kinetic luminosity supplied by the winds

Mass, density, and ionization equilibrium of the plasmaMx~4×10-4 M◎ 　； ne~100 cm-3 ; t~103 yr ; ne t~ 3×1012

N/O ~ 3 (solar units)

Ne/O ~ 7 (solar units)

Remainder of CNO cycle

We have successfully detected the He-burning products at the final evolutionary stage of a low-mass star!

Documents

The Suzaku PV observation of the Planetary Nebula BD+30°3639