Identifying Progenitors of Stripped-Envelope Supernovae

Transcription

1 Identifying Progenitors of Stripped-Envelope Supernovae Gastón Folatelli Instituto de Astrofísica de La Plata (IALP), CONICET, Argentina Aug 11th, 2016 Collaborators: S. Van Dyk, H. Kuncarayakti, K. Maeda, M. Bersten, O. Benvenuto, K. Nomoto, G. Pignata, M. Hamuy, R. Quimby, W. Zheng, A. Filippenko, N. Smith, N. Elias-Rosa, R. J. Foley, A. A. Miller G. Folatelli (IALP) SE-SN Progenitors SNe Through the Ages 1 / 12

2 Stripped-Envelope Supernova Progenitors Progenitor detections Powerful method (d 30 Mpc) Combined with evolutionary models to get initial masses SNe II associated with RSG (also YSG) (Smartt+09,15, Van Dyk+12) SN 1987A: BSG; SNe IIb: YSG SN 2008bk: progenitor SN confirmation SNe Ib/Ic: no detections (Eldridge+13) until iptf13bvn (SN Ib) Hot progenitors (optically faint)/ dusty environments Possible channels for stripped SNe Single, massive WR stars (M ini 25M ) Smartt15 Interacting binaries with lower constraint on M ini G. Folatelli (IALP) SE-SN Progenitors SNe Through the Ages 2 / 12

3 The Type IIb Supernova 2008ax (d 8 Mpc) SN 2008ax in NGC 4490 Progenitor candidate (Crockett+08) Nearby, well-observed Type IIb SN (Pastorello+08, Martí-Vidal+09, Roming+09, Tsvetkov+09, Taubenberger+11, Chornock+ 11, and more) Blue, luminous pre-sn object detected in archival HST images Uncertain nature: massive WR star or interacting binary Fast light curve = low ejected mass = not WR? Lacked post-sn confirmation from disappearance of progenitor pre-sn HST images (1994/2001) G. Folatelli (IALP) SE-SN Progenitors SNe Through the Ages 3 / 12

4 The Type IIb Supernova 2008ax (d 8 Mpc) New HST images in 2011 and 2013 using WFC3 (improved resolution) 1994: unresolved progenitor 2011: SN + 3 objects 2013: SN disappears Pre-SN object disappeared Three nearby sources resolved (A, B, C) Subtraction of flux from A,B,C = refined progenitor Folatelli+15 G. Folatelli (IALP) SE-SN Progenitors SNe Through the Ages 4 / 12

5 The progenitor of SN 2008ax revisited Subtracted SED: fainter and bluer Binary scenario explains all observables Hot companion should be below MS O9 B0 G. Folatelli (IALP) SE-SN Progenitors SNe Through the Ages 5 / 12

6 The Type Ib Supernova iptf13bvn (d 26 Mpc) Possibly first SNIb progenitor Blue prog. candidate (Cao+13) Massive WN star models fit pre-sn photometry (Groh+13) Hydro LC models suggest low mass. Binary? (Bersten+14) Also from [O I] line in neb. spectrum (Kuncarayakti+15) Revised pre-sn photometry favors binary (Eldridge+15, Kim+15) Bersten+14 Pre-SN HST imaging B V I Kim+15 Cao+13 G. Folatelli (IALP) SE-SN Progenitors SNe Through the Ages 6 / 12

7 Testing the progenitor candidate New imaging with HST in 2015: check progenitor disappearance (1.5 h in BV + 40 min in I) + search for companion (2.5 h in UV) Faint object detected in BVI. No detection in UV (Folatelli+16) UV B V I G. Folatelli (IALP) SE-SN Progenitors SNe Through the Ages 7 / 12

8 Interpreting the new photometry Dimming of 3-4σ in BV suggests progenitor disappeared We likely detected the fading SN = Pre-SN object was mostly the progenitor Dust formation is not likely because it would change the SED Folatelli+16 G. Folatelli (IALP) SE-SN Progenitors SNe Through the Ages 8 / 12

9 Interpreting the new photometry Dimming of 3-4σ in BV suggests progenitor disappeared We likely detected the fading SN = Pre-SN object was mostly the progenitor Dust formation is not likely because it would change the SED Folatelli+16 G. Folatelli (IALP) SE-SN Progenitors SNe Through the Ages 8 / 12

10 Comparison with evolutionary models Single stars: consistent with rotating models of 20 and 28 M (Groh+13) But too massive to fit the SN light curves (Bersten+14, Fremling+14) Binaries: too massive companions (35 M ) to comply with UV limit Folatelli+16 G. Folatelli (IALP) SE-SN Progenitors SNe Through the Ages 9 / 12

11 Comparison with evolutionary models Binary scenario seems to be favored Companions of up to 20 M are allowed Eldridge+Maund 2016 suggested low-mass binary ( 12 M prim.) based on BV data and revised models Confirmation must wait for future observations (if time is granted) G. Folatelli (IALP) SE-SN Progenitors SNe Through the Ages 10 / 12

12 Summary The connection between different types of SNe and their progenitors is still an open issue Stripped-envelope SNe can provide clues about the mass-loss history and the role of binarity among massive stars Direct progenitor detection is a powerful tool in the nearby universe ( 30 Mpc). Its utility relies on stellar evolution models Examples: SN 2008ax is the third SN IIb with confirmed progenitor detection iptf13bvn may be the first SN Ib with identified progenitor Both may have binary origin G. Folatelli (IALP) SE-SN Progenitors SNe Through the Ages 11 / 12

13 Comparison with evolutionary models Folatelli+16 G. Folatelli (IALP) SE-SN Progenitors SNe Through the Ages 12 / 12