Subaru Users Meeting (January 15, 2009)

Light-Echo Spectrum revealed types of Tycho Brahes’s 1572 & Cas A SNe

Cas ABlue ： X-ray (CXO)Green ： Optical (HST)Red ： Mid-IR (SST)

Tomonori Usuda (SUBARU)

Oliver Krause, Stephan M. Birkmann, Miwa Goto (MPIA), Takashi Hattori (Subaru Telescope),

Masaomi Tanaka, Ken’ichi Nomoto (Univ. of Tokyo),

George H. Rieke, Karl A. Misselt (Steward Observatory)

TychoBGY ： X-ray (CXO)Red ： Mid-IR (SST)White: Near-IR

Subaru Users Meeting (January 15, 2009)

Outline1. Review Galactic Supernova Remnants (SNRs) &

Historical Supernovae (SNe)

• Cassiopeia A (Cas A)

• Tycho Brahe’s SN 1572

2. Special Observation Tool: Light echo

3. Case 1: Cas A – Observation / Results

4. Case 2: Tycho – Observation / Results

5. Future plans & Conclusion

Subaru Users Meeting (January 15, 2009)

Designation Year Type

RCW86 185 II / Ia ?

G11.2-0.3 393 ?

Lupus 1006 Ia

Crab 1054 II

3C58 1181 ? II ?

Tycho 1572 Ia

Kepler 1604 Ia / Ib ?

Cas A 1680 ? Ib / Ic / II ?

G1.9+0.3 1870? ?

Review Galactic Supernova?

Kepler

G11.2

RCW86

Tycho Brahe

Crab

Cassiopeia A

G1.9

Subaru Users Meeting (January 15, 2009)

Cassiopeia A

• Second youngest SNR known in our Galaxy(cf. G1.9+0.3 discovered by CXO in 05/13/2008)

• Well known & studied SNR

• It might be appeared around 1680, however no historic records(e.g., SN1054: Crab by Teika Fujiwara 『 Meigetsuki 』 )

Q1: What kind of supernova explosion?

Q2: Why it was not witnessed in 17th century?

Subaru Users Meeting (January 15, 2009)

Tycho Brahes’s 1572 Supernova• Well known & studied SNR• Danish astronomer Tycho Brahe found very bright `new

star’ in the constellation of Cassiopeia on the evening of 11th of November in 1572. He had observed its brightness, color, and proper motion until March in 1574.

• In 20th century, the `new star’ = A supernova– Brightness & Color light curve ←→ Theoretical Model of SN

– X-ray observations → Spherical symmetry of metal abundance

– Radio etc. → No pulser

– Optical → Candidate of surviving binary companion of SN 1572

Q: Is SN 1572 really type Ia Supernova?

→ Classified by only optical spectrum``Astronomie Populaire” by Camille Flammarion (Paris, 1884)

Subaru Users Meeting (January 15, 2009)

How we can solve the mysteries on the past?!

Light Echo can go back to the past rewind time

Subaru Users Meeting (January 15, 2009)

Light echoes – Rewinding time to historic SN explosions

Echo (sound)2800 ft

(850m)

5 seconds

Subaru Users Meeting (January 15, 2009)

Light echoes – Rewinding time to historic SN explosions

Blue : Light of SN explosion arrived at Earth in 1572.

Red : Scattered-light echo by dust arrives now.

Subaru Users Meeting (January 15, 2009)

"As Professor J.H. Oort has pointed out to us, the illumination of surrounding clouds might become a spectacular phenomenon in the case of galactic supernovae. The search for the illumination of galactic clouds by past suspected supernovae such as Tycho's star and the stars which gave rise to the Crab Nebula and perhaps other nebulosities presents an interesting problem”.

By Zwicky Rev. Mod. Phys. 12, 66 (1940)

Light echoes – Rewinding time to historic SN explosions

Suntzeff

SN 1987A

Subaru Users Meeting (January 15, 2009)

However… Observation of Light echo is very difficult.

•Very Faint (Light echo became fainter and fainter day by day)

→ Even though can detect light echo, difficult to take its spectrum

•When? Where? How bright?

→ Just wait and Searching

Light echoes – Rewinding time to historic SN explosions

Suntzeff

SN 1987A

Echo geometry

Dust cloud

SN

Subaru Users Meeting (January 15, 2009)

Observations• When? Where? How bright?

→ Monitoring and ToO (Target of Opportunity)

→ International collaborations with MPIA

• Calar Alto 2.2m & 3.5m + Wide Optical Camera

PI: Oliver Krause (MPIA)

→ Monitoring & Looking for optical light echo

• Subaru Telescope 8.3m + FOCAS

PI: Tomonori Usuda (Subaru/NAOJ)

→ Imaging: Re-confirmation of light echo

Spectroscopy: Take its optical spectrum

Subaru Users Meeting (January 15, 2009)

Case 1: Cassiopeia A

Subaru Users Meeting (January 15, 2009)

October 9, 2007

Spectro-scopy

Associated scattered light echo by Calar Alto 2.2m & SUBARU 8.2m

SUBARU+

FOCAS

Detect optical light echo!

R = 23.4 mag / arcsec2

Subaru Users Meeting (January 15, 2009)

•=2.4nm (476~989 nm) / Av=3.1 mag•Exp time=5.5 hours

Results: Spectroscopy

•Spectral features of Supernovae•Broad line width (17,000 km/s) / P-Cygni profile•Strong H & He emission lines

He I Hα He IWent back in time to detect light that originally arrived at Earth more

than 330 years ago.

Subaru Users Meeting (January 15, 2009)

ResultsType sub-type Spectral Feature

I

Ia•No Hydrogen lines•Strong Si lines•Remarkable Fe lines in later phases

Ib•No Hydrogen lines•Remarkable He lines in max period•Weak Si lines / No Fe lines

Ic•No H & He lines•Weak Si lines / No Fe lines

IIII

•Strong H lines•Light curve → II-P-type (plateau), II-L-type (linear), II-n-type (narrow)

IIb•Visible H lines•Remarkable He lines

Subaru Users Meeting (January 15, 2009)

Comparison with the proto-typicaltype IIb SN 1993J

Subaru Users Meeting (January 15, 2009)

ResultsType sub-type Spectral Feature

I

Ia•No Hydrogen lines•Strong Si lines•Remarkable Fe lines in later phases

Ib•No Hydrogen lines•Remarkable He lines in max period•Weak Si lines / No Fe lines

Ic•No H & He lines•Weak Si lines / No Fe lines

IIII

•Strong H lines•Light curve → II-P-type (plateau), II-L-type (linear), II-n-type (narrow)

IIb•Visible H lines•Remarkable He lines

Subaru Users Meeting (January 15, 2009)

Cas A was a type IIb SN & Red Supergiant (13-20 Solar Mass) as progenitor star

Comparison with the proto-typicaltype IIb SN 1993J

Subaru Users Meeting (January 15, 2009)

Case 2: Tycho

Subaru Users Meeting (January 15, 2009)

N

E

30”

Results: Imaging

a: Calar Alto 2.2mb: Subaru ＋ FOCAS

Back box: Previous light echo position in 2006

Red+ mark: Brightest position (R=23.5 mag)

→ Slit position (2.8”x2.0”) for spectroscopy by FOCAS

→ Subtraction of sky & nebulosity lines

Center of SNR

Center of SNR

Slit positionShift

Subaru Users Meeting (January 15, 2009)

Results: Spectroscopy

•Remarkable spectral features of Supernovae•Broad line width (9,000~12,000 km/s)•No H & He lines•Strong absorption lines of Si and Fe

Hα

Si

He

Optical spectrum of the light that originally arrived at Earth in 1572

•=2.4nm (380~920 nm) / Av=2.4 mag•Exp time=2.5 hours (Red) + 1.5 hours (Blue)

Subaru Users Meeting (January 15, 2009)

ResultsType sub-type Spectral Feature

I

Ia•No Hydrogen lines•Strong Si lines•Remarkable Fe lines in later phases

Ib•No Hydrogen lines•Remarkable He lines in max period•Weak Si lines / No Fe lines

Ic•No H & He lines•Weak Si lines / No Fe lines

IIII

•Strong H lines•Light curve → II-P-type (plateau), II-L-type (linear), II-n-type (narrow)

IIb•Visible H lines•Remarkable He lines

Subaru Users Meeting (January 15, 2009)

Results: Spectroscopy

•Spectral features of Supernovae•Broad line width (9,000~12,000 km/s)•No H & He lines•Strong absorption lines of Si and Fe

→ Type Ia Supernova

Hα

Si

He

Subaru Users Meeting (January 15, 2009)

ResultsType sub-type Spectral Feature

I

Ia•No Hydrogen lines•Strong Si lines•Remarkable Fe lines in later phases

Ib•No Hydrogen lines•Remarkable He lines in max period•Weak Si lines / No Fe lines

Ic•No H & He lines•Weak Si lines / No Fe lines

IIII

•Strong H lines•Light curve → II-P-type (plateau), II-L-type (linear), II-n-type (narrow)

IIb•Visible H lines•Remarkable He lines

Subaru Users Meeting (January 15, 2009)

Type Ia SN = Cosmological distance indicator

→ Discovery of the accelerated expansion of Universe

Luminosity is NOT uniform!

Various type Ia Supernova

Normal

Type Ia SN OverluminousSubluminous

Reason why its variety of luminosity?→ Accurate cosmological distance indicator?

SiCa

FeNi

SiCa

FeNi

SiCa

FeNi

Subaru Users Meeting (January 15, 2009)

Results: Spectroscopy

Overluminous type Ia

Normal type Ia

Subluminous type Ia

Tycho was normal type Ia SN

Subaru Users Meeting (January 15, 2009)

Unique opportunity to test theories of SN Explosion mechanism

d=100 Mpc d = 3.8 kpc

10 arcmin

SNe in extra-galaxies Tycho’s SNR

Point source

Subaru Users Meeting (January 15, 2009)

Spatial Resolved Investigation

HighVelocity Ca II

Subaru Users Meeting (January 15, 2009)

Conclusions• For the first time, spectra of historical Galactic supernovae

(Cas A & Tycho) have been secured.

• Cas A: Type IIb SN & Red Supergiant (13~20 Mo)

• Why Cas A was not witnessed in 17th century

Type IIb SN fade away quickly, poor weather of several days, higher extinction (Av~8), peak brightness (~3 mag)

• Tycho: Normal type Ia SN & d=3.4kpc (cf. 2.3~2.8 kpc)

• Light echoes at different position angles from the source

→3D aspect

→ Spatial structure of SN outburst mechanism

Subaru Users Meeting (January 15, 2009)

Mahalo !