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Subaru Users Meeting (January 15, 2009) Light-Echo Spectrum revealed types of Tycho Brahes’s 1572 & Cas A SNe 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) Cas A Blue:X-ray (CXO) Green:Optical (HST) Red:Mid-IR (SST) Tycho BGY:X-ray (CXO) Red:Mid-IR (SST) White: Near-IR Subaru Users Meeting (January 15, 2009) Outline 1. 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) Review Galactic Supernova? RCW86 G11.2 Kepler Designation RCW86 G11.2-0.3 Lupus Crab 3C58 Tycho Kepler Cas A Year 185 393 1006 1054 1181 ? 1572 1604 1680 ? Type II / Ia ? ? Ia II II ? Ia Ia / Ib ? Ib / Ic / II ? G1.9+0.3 1870? ? 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) 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) Light echoes – Rewinding time to historic SN explosions "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”. SN 1987A By Zwicky Rev. Mod. Phys. 12, 66 (1940) Suntzeff Subaru Users Meeting (January 15, 2009) Light echoes – Rewinding time to historic SN explosions 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 Dust cloud SN 1987A SN Echo geometry Suntzeff 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) Associated scattered light echo by Calar Alto 2.2m & SUBARU 8.2m October 9, 2007 Spectroscopy Detect optical light echo! R = 23.4 mag / arcsec2 SUBARU + FOCAS Subaru Users Meeting (January 15, 2009) Results: Spectroscopy He I He I Went back in time toHαdetect light that originally arrived at Earth more than 330 years ago. • dl=2.4nm (ll=476~989 nm) / Av=3.1 mag • Spectral features of Supernovae • Exp time=5.5 hours • Broad line width (17,000 km/s) / P-Cygni profile • Strong H & He emission lines Subaru Users Meeting (January 15, 2009) Type I sub-type Results Spectral Feature 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 II • Strong H lines • Light curve → II-P-type (plateau), II-L-type (linear), II-n-type (narrow) IIb • Visible H lines • Remarkable He lines II Subaru Users Meeting (January 15, 2009) Comparison with the proto-typical type IIb SN 1993J Subaru Users Meeting (January 15, 2009) Type I sub-type Results Spectral Feature 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 II • Strong H lines • Light curve → II-P-type (plateau), II-L-type (linear), II-n-type (narrow) IIb • Visible H lines • Remarkable He lines II Subaru Users Meeting (January 15, 2009) Comparison with the proto-typical type IIb SN 1993J Cas A was a type IIb SN & Red Supergiant (13-20 Solar Mass) as progenitor star Subaru Users Meeting (January 15, 2009) Case 2: Tycho Subaru Users Meeting (January 15, 2009) Results: Imaging N E Slit position 30” Back box: Previous light echo position in 2006 a: Calar Alto 2.2m b: Subaru+FOCAS Red+ mark: Brightest position (R=23.5 mag) → Slit position (2.8”x2.0”) for spectroscopy by FOCAS → Subtraction of sky & nebulosity lines Subaru Users Meeting (January 15, 2009) Results: Spectroscopy He Hα Si Optical spectrum of the light that originally arrived at Earth in 1572 • dl=2.4nm (ll=380~920 nm) / Av=2.4 mag • Exp time=2.5 hours (Red) + 1.5 hours (Blue) • 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 Subaru Users Meeting (January 15, 2009) Type I sub-type Results Spectral Feature 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 II • Strong H lines • Light curve → II-P-type (plateau), II-L-type (linear), II-n-type (narrow) IIb • Visible H lines • Remarkable He lines II Subaru Users Meeting (January 15, 2009) Results: Spectroscopy He Hα Si • 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 Subaru Users Meeting (January 15, 2009) Type I sub-type Results Spectral Feature 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 II • Strong H lines • Light curve → II-P-type (plateau), II-L-type (linear), II-n-type (narrow) IIb • Visible H lines • Remarkable He lines II Subaru Users Meeting (January 15, 2009) Various type Ia Supernova Type Ia SN = Cosmological distance indicator → Discovery of the accelerated expansion of Universe Luminosity is NOT uniform! Subluminous Si Ca Fe Si Ni Normal Type Ia SN Si Ca Fe Ni Overluminous Si Ca Fe Ni Reason why its variety of luminosity? → Accurate cosmological distance indicator? Subaru Users Meeting (January 15, 2009) Results: Spectroscopy Overluminous type Ia Normal type Ia Subluminous type Ia Subaru Users Meeting (January 15, 2009) Unique opportunity to test theories of SN Explosion mechanism 10 arcmin Point source SNe in extra-galaxies Tycho’s SNR d=100 Mpc d = 3.8 kpc 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 !