SN2018gep: The Death Throes of a Stripped Massive Star

Transcript

1. SN2018gep: The Death Throes of a Stripped Massive Star Anna Y. Q. Ho (Caltech) Zwicky Transient Facility (ZTF) with D. Goldstein, S. Schulze, D. Khatami, D. Perley, M. Ergon, A. Gal-Yam, A. Corsi, R. Lunnan, S. Kulkarni — and the ZTF partnership
2. Before PTF/iPTF, 7.3 deg2 HSC, 1.7 deg2 ZTF, 47 deg2 1 deg LSST, 9.6 deg2 PS1, 7 deg2 DES, 2.5 deg2 ZTF high-cadence survey: discover explosions early 1725 deg2, 6x per night (Bellm et al. 2019)
3. Sept 9: a discovery in the ZTF high-cadence survey Before
4. Sept 9: a discovery in the ZTF high-cadence survey Before
5. After Before SDSS Sept 9: a discovery in the ZTF high-cadence survey
6. After Before Difference image Sept 9: a discovery in the ZTF high-cadence survey
7. 18 19 20 21 Apparent Mag P48 g P48 r 0.3 0.4 rg/s/Hz] t0 = −25 ± 2 min 1.3 mag/hr 18 19 20 21 Apparent Mag P48 g P48 r −50 0 50 100 150 Minutes since ZTF discovery 0.0 0.1 0.2 0.3 0.4 Lν [1028 erg/s/Hz] t0 = −25 ± 2 min P48 g P48 r 18 19 20 21 Apparent Mag P48 g P48 r 0.3 0.4 rg/s/Hz] t0 = −25 ± 2 min Minutes Since ZTF Discovery After Before Difference image SDSS Sept 9: a discovery in the ZTF high-cadence survey
8. 18 19 20 21 Apparent Mag P48 g P48 r 0.3 0.4 rg/s/Hz] t0 = −25 ± 2 min 1.3 mag/hr 18 19 20 21 Apparent Mag P48 g P48 r −50 0 50 100 150 Minutes since ZTF discovery 0.0 0.1 0.2 0.3 0.4 Lν [1028 erg/s/Hz] t0 = −25 ± 2 min P48 g P48 r 18 19 20 21 Apparent Mag P48 g P48 r 0.3 0.4 rg/s/Hz] t0 = −25 ± 2 min Minutes Since ZTF Discovery After Before Difference image SDSS Sept 9: a discovery in the ZTF high-cadence survey
9. 18 19 20 21 Apparent Mag P48 g P48 r 0.3 0.4 rg/s/Hz] t0 = −25 ± 2 min 1.3 mag/hr 18 19 20 21 Apparent Mag P48 g P48 r −50 0 50 100 150 Minutes since ZTF discovery 0.0 0.1 0.2 0.3 0.4 Lν [1028 erg/s/Hz] t0 = −25 ± 2 min P48 g P48 r 18 19 20 21 Apparent Mag P48 g P48 r 0.3 0.4 rg/s/Hz] t0 = −25 ± 2 min Minutes Since ZTF Discovery IAU name: AT2018gep After Before Difference image SDSS Sept 9: a discovery in the ZTF high-cadence survey (ATel: Ho+ 2018)
10. Sept 10: Swift + optical spectroscopy 0 1 2 3 4 5 Days since ZTF discovery 15 16 17 18 19 20 21 22 Apparent Mag Swift LT P200, P60 LT P200 LT P200 P200 LRIS DCT VLA −21 −20 −19 −18 −17 −16 −15 −14 Absolute Mag UVW2 g-band r-band g-band r-band (ATel: Ho+2018, Schulze+ 2018)
11. Sept 10: Swift + optical spectroscopy 0 1 2 3 4 5 Days since ZTF discovery 15 16 17 18 19 20 21 22 Apparent Mag Swift LT P200, P60 LT P200 LT P200 P200 LRIS DCT VLA −21 −20 −19 −18 −17 −16 −15 −14 Absolute Mag UVW2 g-band r-band g-band r-band blue (hot) (ATel: Ho+2018, Schulze+ 2018)
12. Sept 10: Swift + optical spectroscopy 0 1 2 3 4 5 Days since ZTF discovery 15 16 17 18 19 20 21 22 Apparent Mag Swift LT P200, P60 LT P200 LT P200 P200 LRIS DCT VLA −21 −20 −19 −18 −17 −16 −15 −14 Absolute Mag UVW2 g-band r-band g-band r-band —> z=0.032 (140 Mpc) blue (hot) (ATel: Ho+2018, Schulze+ 2018)
13. Sept 10: Swift + optical spectroscopy 0 1 2 3 4 5 Days since ZTF discovery 15 16 17 18 19 20 21 22 Apparent Mag Swift LT P200, P60 LT P200 LT P200 P200 LRIS DCT VLA −21 −20 −19 −18 −17 −16 −15 −14 Absolute Mag UVW2 g-band r-band g-band r-band —> z=0.032 (140 Mpc) blue (hot) (ATel: Ho+2018, Schulze+ 2018)
14. One of the most rapidly rising & luminous transients to date 14 Fig modified from Margutti et al. (2019) Type I superluminous supernovae Stripped-envelope (Type Ibc) core- collapse supernovae Type IIP supernovae IIL supernovae IIn supernovae 18gep “Fast-luminous” transients See also: Drout+ 2014 Tanaka+ 2016 Arcavi+ 2016 Kasen+ 2017 Whitesides+ 2017 Rest+ 2018 Pursiainen+ 2018 Smartt+ 2018 Prentice+ 2018 Perley+ 2019
15. 0 1 2 3 4 5 Days since ZTF discovery 15 16 17 18 19 20 21 22 Apparent Mag Swift LT P200, P60 LT P200 LT P200 P200 LRIS DCT VLA −21 −20 −19 −18 −17 −16 −15 −14 Absolute Mag By Sept 14: UV, X-ray, nine optical spectra, radio obs UVW2 g-band r-band
16. 0.7 days 5 days
17. carbon and oxygen at high temperatures (CIII, CIV, OIII, OIV, …) 0.7 days 5 days
18. 45,000 km/s high-velocity material 30,000 km/s 0.7 days 5 days carbon and oxygen at high temperatures (CIII, CIV, OIII, OIV, …)
19. Sept 17 (Day 8): Spectra evolved into a supernova (Type Ic-BL) high-redshift analog: iPTF16asu (Whitesides, Lunnan+ 2017)
20. Core-collapse supernova (1051 erg) Sept 17 (Day 8): Spectra evolved into a supernova (Type Ic-BL)
21. 10%: Ic Stripped of H, He Core-collapse supernova (1051 erg) Sept 17 (Day 8): Spectra evolved into a supernova (Type Ic-BL)
22. 1%: Ic-BL* “broad-lined” 10%: Ic Stripped of H, He Core-collapse supernova (1051 erg) (> 1052 erg) Sept 17 (Day 8): Spectra evolved into a supernova (Type Ic-BL)
23. 1%: Ic-BL* “broad-lined” 10%: Ic Stripped of H, He Core-collapse supernova (1051 erg) (> 1052 erg) GRB Sept 17 (Day 8): Spectra evolved into a supernova (Type Ic-BL)
24. 1%: Ic-BL* “broad-lined” 10%: Ic Stripped of H, He Core-collapse supernova (1051 erg) (> 1052 erg) GRB GRB Ic-BL SN? Sept 17 (Day 8): Spectra evolved into a supernova (Type Ic-BL)
25. 1%: Ic-BL* “broad-lined” 10%: Ic Stripped of H, He Core-collapse supernova (1051 erg) (> 1052 erg) GRB GRB Ic-BL SN? Sept 17 (Day 8): Spectra evolved into a supernova (Type Ic-BL) Our early data: the earliest spectra of a stripped-envelope SN
26. Light curve not powered by radioactive decay 0 10 20 30 40 Days since first light 1042 1043 1044 1045 Lbol (erg/s) Ic-BL 0 10 20 Days since first li
27. 0 10 20 30 40 Days since first light 1042 1043 1044 1045 Lbol (erg/s) Ic-BL SN2018gep 0 10 20 Days since first li Lpeak > 4 x 1044 erg/s tpeak = 1-3 days Light curve not powered by radioactive decay
28. High temperatures, large radius 1042 0 2 4 6 Rph (1015 cm) v=0.1c 0 10 20 30 40 Days since t0 104 Teff (K) 5000 K 200 400 600 (AU) first point: ~3x1014 cm, ∆t~hours
29. What about shock breakout? Lpeak > 4 x 1044 erg/s tpeak = 1-3 days
30. What about shock breakout? R* Lpeak > 4 x 1044 erg/s tpeak = 1-3 days
31. What about shock breakout? R* vsh Lpeak > 4 x 1044 erg/s tpeak = 1-3 days
32. What about shock breakout? R* vsh vdiff Lpeak > 4 x 1044 erg/s tpeak = 1-3 days
33. What about shock breakout? R* vsh vdiff Lpeak > 4 x 1044 erg/s tpeak = 1-3 days
34. What about shock breakout? R* vsh vdiff tBO ~ R*/vsh Lpeak > 4 x 1044 erg/s tpeak = 1-3 days
35. What about shock breakout? R* vsh vdiff tBO ~ R*/vsh Lpeak > 4 x 1044 erg/s tpeak = 1-3 days
36. What about shock breakout? R* vsh vdiff tBO ~ R*/vsh Lpeak > 4 x 1044 erg/s tpeak = 1-3 days
37. Proof of concept: CASTRO simulations With David Khatami (Berkeley)
38. Proof of concept: CASTRO simulations 1042 1043 1044 1045 Lbol (erg/s) Model SN2010bh, x2 Model + SN2010bhx2 SN2018gep 100 101 (1015 cm) 109 1010 1011 (L⊙) 400 600 (AU) 10−1 100 Rph (1015 c Model 0 5 10 15 Days since t0 104 Teff (K) 5000 K Model Lbol /(4πR2σ) 200 400 (AU) CSM interaction Ic-BL light curve CSM Interaction + Ic-BL ESN=1052 erg, MCSM = 0.02 solar mass, RCSM = 3x1014 cm With David Khatami (Berkeley)
39. 39 1042 1043 Lbo 10−1 100 101 Rph (1015 cm) Model 0 5 10 15 Days since t0 104 Teff (K) 5000 K Model Lbol /(4πR2σ) 109 ) 200 400 600 (AU) Proof of concept: CASTRO simulations ESN=1052 erg MCSM = 0.02 solar mass RCSM = 3x1014 cm CSM interaction CSM interaction CSM interaction + Ic-BL With David Khatami (Berkeley)
40. ZTF coaddition pipeline: Danny Goldstein (Hubble Fellow, Caltech) Search for pre-explosion emission
41. −17.5 −15.0 −12.5 −10.0 −7.5 −5.0 −2.5 0.0 Days since ZTF discovery 16 18 20 22 Apparent Mag Swift LT P200, P60 LT P200 −20 −18 −16 −14 Absolute Mag Aug 24-27 Sep 3-6 −20 −10 0 10 20 30 40 50 60 Days since ZTF discovery 22 A −14 ag ZTF coaddition pipeline: Danny Goldstein (Hubble Fellow, Caltech) Search for pre-explosion emission
42. ZTF coaddition pipeline: Danny Goldstein (Hubble Fellow, Caltech) −17.5 −15.0 −12.5 −10.0 −7.5 −5.0 −2.5 0.0 Days since ZTF discovery 16 18 20 22 Apparent Mag Swift LT P200, P60 LT P200 −20 −18 −16 −14 Absolute Mag Aug 24-27 Sep 3-6 −20 −10 0 10 20 30 40 50 60 Days since ZTF discovery 22 A −14 ag Search for pre-explosion emission First definitive pre-explosion detection of a Ic-BL (but see also PTF11qcj; Corsi et al. 2014)
43. ~1014 cm at 10 days First definitive pre-explosion detection of a Ic-BL (but see also PTF11qcj; Corsi et al. 2014) −17.5 −15.0 −12.5 −10.0 −7.5 −5.0 −2.5 0.0 Days since ZTF discovery 16 18 20 22 Apparent Mag Swift LT P200, P60 LT P200 −20 −18 −16 −14 Absolute Mag Aug 24-27 Sep 3-6 −20 −10 0 10 20 30 40 50 60 Days since ZTF discovery 22 A −14 ag ZTF coaddition pipeline: Danny Goldstein (Hubble Fellow, Caltech) Search for pre-explosion emission
44. Many outstanding mysteries * What powers the LC at late times? * What is the source of the pre-explosion emission? * What are the implications for detecting a jet/GRB? * … An eruptive mass-loss history encoded in a fast-luminous transient, a Ic-BL SN, and pre-explosion emission Highlights * Earliest spectra of stripped-envelope SN * First definitive detection of pre-explosion emission for a Ic-BL * Connection to the mysterious “fast-luminous transients” * Evidence for eruptive mass-loss in Ic-BL progenitor ah@astro.caltech.edu
51. Velocities similar to Ic-BL associated with GRBs 0 5 10 15 20 25 Time since explosion (days) 101 102 2 × 101 3 × 101 4 × 101 6 × 101 Fe II Velocity (103 km/s) iPTF16asu SN2017iuk SN1998bw SN2006aj SN2003lw SN2010bh LLGRB-SN SN2018gep GRB-SNe 100,000 km/s 10,000 km/s 60,000 km/s 40,000 km/s 30,000 km/s 20,000 km/s
52. 0 10 20 30 40 Days since first light 1042 1043 1044 1045 Lbol (erg/s) Ic-BL SN2018gep 0 10 20 30 40 Days since first light AT2018cow SN2018gep
56. −0.6 −0.4 −0.2 0.0 0.2 0.4 0.6 0.8 1.0 g − r, observer frame −20 −19 −18 −17 −16 Absolute g-band mag, observer frame SN2018gep AT2018cow KSN2015K 1 hour 1 day 10 days 20 days