CSI: LMC Type Ia Supernova Remnants

You-Hua Chu University of Illinois

Academia Sinica Institute of Astronomy

and Astrophysics (ASIAA)

R.A. Gruendl, K.C. Pan, P.M. Ricker, R. Foley,

A. Holmes, K. Litke, R. Tippens, D. Weisz

1. Surviving companions in Type Ia SNRs 2. Identification of Type Ia SNRs 3. HST search for surviving companions in Type Ia SNRs in the LMC

1. Surviving companions in Type Ia SNRs 2. Identification of Type Ia SNRs 3. HST search for surviving companions in Type Ia SNRs in the LMC

Two Origins of Supernovae (SNe)

Core-collapse SNe – massive stars Type Ia SNe - white dwarfs (WDs)

Type Ia SN – two possibilities

(1)Single degenerate WD with a normal star companion (2) Double degenerate merger of 2 WDs

Supernova Progenitors

Luminous massive stars can be detected in pre-explosion images.

SN2003gd (Smartt et al. 2004)

After Before

Progenitors of SNe Ia are too faint to be identified.

Was it single degenerate (SD) or double degenerate (DD)?

Embarrassing -- SNe Ia are cosmological distance indicators…

Single Degenerate Scenario of Ia SN

The surviving companion may be identified by its - Faster rotation - Chemical pollution - “Runaway” velocity - Anomalous color and luminosity

Evolution of a Surviving Companion

Pan, Ricker, Taam 2010, 2012

He Star MS star

The surviving companion may be identified by its - Faster rotation - Chemical pollution - “Runaway” velocity - Anomalous color and luminosity

If a surviving companion is found, the SD origin is affirmed.

Searching for Surviving Companions

SN 1006 - Gonzalez-Hernandez et al. 2012 - Kerzendorf et al. 2012 - no surviving companion is found

Tycho’s SN 1572 - Ruiz-Lapuente et al. 2004 (Tycho-G) - Gonzalez-Hernandez et al. 2009 ([Ni/Fe] high) - Kerzendorf et al. 2012 (Ni/Fe normal, no cand.)

Kepler’s SN 1604 - Kerzendorf et al. 2013 (no red giant or >10L

)

Photo credit: Roger Smith

The Large Magellanic Cloud distance 50 kpc; DM = 18.5

Kerzendorf uses Gemini GMOS to Take spectra of the brightest stars in Ia SNRs.

It is possible to use HST images and color-magnitude diagrams to diagnose surviving companions.

Searching for Surviving Companions

SNR 0509-67.5 SNR 0519-69.0

Shaefer & Pagnotta 2012 Edwards et al. 2012 (only V and Hα)

1. Surviving companions in Type Ia SNRs 2. Identification of Type Ia SNRs 3. HST search for surviving companions in Type Ia SNRs in the LMC

Identification of Type Ia SNRs

Balmer-dominated SN ejecta running into a neutral medium; collisionless shock (Chevalier et al. 1980)

SNR 0509-67.5 Hα + X-ray

Size 7 pc

Identification of Type Ia SNRs

Balmer-dominated X-ray Kα emission of Si,S,Ar,Ca,Fe

Hα X-ray

DEM L71 Size 20 pc

Identification of Type Ia SNRs

Balmer-dominated X-ray Kα emission of Si,S,Ar,Ca,Fe

Type Ia SNR

C-C SNR

LMC ISM

Hughes et al. 1995

Identification of Type Ia SNRs

Balmer-dominated X-ray Kα emission of Si,S,Ar,Ca,Fe Spectra of SN light echoes

Light echoes of: SN1987A

Identification of Type Ia SNRs

Balmer-dominated X-ray Kα emission of Si,S,Ar,Ca,Fe Spectra of SN light echoes

Rest et al. 2005, 2008

Light echoes of: SN1987A (27 yr)

N103B (860 yr)

SNR 0519-67.5 (610 yr)

SNR 0509-69.0 (410 yr)

Identification of Type Ia SNRs

Balmer-dominated X-ray Kα emission of Si,S,Ar,Ca,Fe Spectra of SN light echoes Old stellar/interstellar environment

HII & number of blue stars within 100 pc; eliminating C-C SNRs to get Type Ia SNRs (Chu & Kennicutt 1988)

Star formation history; coarse spatial grids (Badenes et al. 2009; Harris & Zaritsky 2009)

4’ = 60 pc

B 0509−67.5

DEM L71

B 0519−69.0 N103B

B 0548−70.4 DEM L316A

Type Ia SNRs in the LMC

B 0509−67.5

DEM L71

B 0519−69.0 N103B

B 0548−70.4 DEM L316A

Type Ia SNRs in the LMC

B 0509−67.5

DEM L71

B 0519−69.0 N103B

B 0548−70.4 DEM L316A

Type Ia SNRs in the LMC

Mg Si S

Ar Ca

S

Si

Si

S

Fe L-shell

B 0534−69.9 DEM L249

DEM L238 B 0454−67.2

Type Ia SNRs in the LMC

4’ = 60 pc

Type Ia SNRs in the LMC B 0534−69.9

B 0454−67.2 DEM L238

DEM L249

(XMM-Newton)

DEM L238 DEM L249

XMM-Central XMM-Shell Chandra-Central Borkowski et al. 2006

Fe L-shell emission

O/Fe ~ 13 for the LMC ISM < 1 for Type Ia SNe > 10 for C-C SNe

Large Type Ia SNRs show O/Fe ~ 1-5. Higher than Ia, but too low for C-C.

Ionization timescale (nt) high CSM density not expected around WDs

“Prompt” Type Ia – 107-108 yr after SF

We Learned from X-ray Spectra

1. Surviving companions in Type Ia SNRs 2. Identification of Type Ia SNRs 3. HST search for surviving companions in Type Ia SNRs in the LMC

HST Program for LMC Type Ia SNRs

Undergraduate “Scientific Writing” project.

Porposal was awarded 16 orbits to image 9 Type Ia SNRs in the LMC: - Search for surviving companions - Determine star formation history

Images in F475W, F555W, F814W, F656N and near-IR F110W, F160W for SNR 0509

The Case of SNR 0509-67.5

Schaefer & Pagnotta 2012

No surviving companion with V < 26.9.

A “smudge” is seen at the center of the SNR. It could be a galaxy; however, a SNR-related origin is not ruled out.

SNR 0509-67.5

We noticed a point-like source in F814W…

F814W (814nm) F110W (1.1μm) Spitzer (3.6μm) It is even more prominent in near-IR.

The SED is made with HST & Spitzer data. The 3.6” aperture is needed for Spitzer, but includes optically bright stars.

- The nucleus is redder than the disk. - Balmer jump? If yes, galaxy at z ≈ 0.8.

Balmer Jump?

Pagnotta, Walker, & Schaefer 2014

Gemini GMOS spectrum Detected one line from the smudge at 6766 Å. Concluded z = 0.031

Gemini GMOS detected line at 676nm.

If Hα line, z = 0.03. Too red.

If [O II] line, z = 0.8. Colors are right.

Photobomb galaxy !

4’ = 60 pc

B 0509−67.5

DEM L71

B 0519−69.0

B 0548−70.4

Four Balmer-Dominated SNRs

No clear candidates for surviving companions at the center of SNR. Abigail Holmes et al. in prep

Three Large Type Ia SNRs

Error circles are large Hard to pin down candidate survivors. Katrina Litke et al. in prep

4’ = 60 pc

The Case of SNR DEM L316

A – SN Ia B - CC SN

Williams & Chu 2005

A B

He stars MS stars

He stars MS stars

The Case of SNR DEM L316

F555-F814 F475-F555

F55

5

F55

5

The spread in the red clump indicates Differential extinction.

F555-F814 F475-F555

F55

5

The Case of SNR DEM L316

Need to examine multiple CMDs. More complicated than expected…

SNR N103B - Young and Prompt?

Rest et al. -- light echo, Type Ia, 860 yr

SNR N103B - Young and Prompt?

HST and Chandra images of N103B

1

2

3 4

5

6 7 8

9

10

11

12

13

SNR N103B - Young and Prompt?

Right positions in the CMD, wrong in the image. No obvious candidate for surviving companion.

Questions: What kind of progenitor?

Are these knots CSM or SN ejecta?

The crime has not been solved. Investigation is still ongoing…