Rapidly Fading Supernovae from Massive Star Explosions. Io Kleiser - Caltech Advisor: Dan Kasen - UC Berkeley 31 October 2013

Transcription

1 Rapidly Fading Supernovae from Massive Star Explosions Io Kleiser - Caltech Advisor: Dan Kasen - UC Berkeley 31 October 213

2 SN 21X Discovery Normalized Magnitude T 1991bg 1994I 21X-g 21X-r 21X-i 22bj-r Extremely rapidly declining light curves! Similar shape to peculiar SN 22bj Days since Peak Kasliwal et al. 21

3 Spectroscopic Comparison with SN 1994I Spectroscopic similarity to other SNe Ic suggests a similar origin, but the light curves decline much more rapidly than normal Ibc SNe

4 A Small but Growing Class Diffusion time (Arnett 1979):!! SN22bj Thermonuclear Supernovae Luminous Supernovae SCP6F6 SN25ap SN28es PTF9cnd SN26gy PTF1cwr PTF9cwl PTF9atu SN27bi Suggests a small ejected mass as in.ia and similar models! Peak Luminosity [M V ] PTF1bhp PTF12bho Core Collapse.Ia Explosions SN27ke Supernovae PTF11bij PTF9dav PTF11kmb SN212hn PTF1iuv SN25E Ca rich Transients SN28ha SN28S Intermediate PTF1acbp Luminosity NGC3OT Red Transients PTF1fqs Peak Luminosity [erg s 1 ] 1 8 P6 M81OT P6 M82OT Classical Novae Luminous Red Novae M85 OT V838 Mon M31 RV 1 39 SN 22bj (Poznanski et al. 21)! 6 V139 Sco 1 38 SN 21X (Kasliwal et al. 21)! Characteristic Timescale [day] SN 25ek (Drout et al. 213)

5 Modeling SN 21X Light Curves & Spectra with SEDONA Kleiser & Kasen 213 submitted to MNRAS, arxiv: Rapidly Fading Supernovae from Massive Star Explosions Io K. W. Kleiser 1, and Daniel Kasen 2,3, 1 Department of Astronomy, California Institute of Technology, Pasadena, CA Lawrence Berkeley National Laboratory, 1 Cyclotron Road, Berkeley, CA Department of Physics, University of California, Berkeley, CA Parameterized 1D simulations in homologous expansion! Broken power law density structure! Uniform composition (two layers: O/Ne-rich and He+solar)

6 Problems with the.ia Model 12 = log density (g/cm3) = =1.1 = = log optical depth temperature (14 K) No radioactive tail seen (could be below limits; could be little -ray trapping)! Deep oxygen features require a large O mass ( ), larger than the total.ia ejected mass of

7 Different Approach: Core-Collapse Model with Recombination If little or no nickel is present, the luminosity could be due to the diffusion of thermal energy deposited in the explosion shock! O recombination allows radiation to be released more rapidly! This is analogous to a Type II plateau (see Ensman & Woosley 1988, Dessart et al. 211)

8 Model Light Curves absolute magnitude model r 14 model g model i 94I U 13 94I B 94I V 94I R 94I I time (days) SN 21X data; representative model fit; Type Ic SN 1994I for comparison Model parameters:!!!! Dominantly O, Ne, Mg in composition

9 Model Spectrum data 24 d model 24 d scaled flux OI wavelength (angstroms) O/Ne/Mg-rich ejecta + thin He/solar outer layer

10 Spectral Time Series scaled flux + constant d 24 d 36 d 9 d 1 d model data 1 d 17 d 24 d 31 d Color evolution is faster in model spectra than in data, but most major features are reproduced! Discrepancies may be due to simplicity of the 1D uniformcomposition model and potentially could be reduced with finer tuning wavelength (angstroms)

11 Hiding Radioactive Nickel

12 Fusion luminosities, durations, convective Mach numbers, and convective Large Presupernova Radii Stage Duration (t nuc ) L fusion (L ) Mach (M conv ) c (s) Carbon 1 3 yr Neon 1 yr Oxygen 1 yr Silicon 1 day See e.g. Quataert & Shiode 212

13 Summary SN 21X and similar SNe (SN 22bj, SN 25ek, others upcoming) are generally thought to be small-mass explosions, perhaps related to the.ia model! Lack of a visible radioactive tail is difficult but not impossible to accommodate in these models! Particularly, prominent oxygen features suggest that a large ejected mass is needed! We explore core-collapse models in which little or no radioactive material is present in the ejecta recombination allows for higher masses (O plateau)! Parameterized radiative transfer calculations agree with the data, but more detailed modeling is required to understand the progenitors! How can we avoid ejecting radioactive nickel?! How can we expand progenitor radii enough to achieve observed luminosities?

14 Host Galaxies Figure 5. Hosts of SN 21X (left) and SN 22bj (right) are both star-forming galaxies and do not constrain the progenitors Kasliwal et al. 21

15 SN 21X Spectrum SYNOW Fit Type Ic light curve showing strong! features of C, O, Ca Kasliwal et al. 21

16 Degeneracy in the Model 18 M ej E 51 These three parameters can be adjusted to fit a wide range of Ni-free light curves! SN 21X can also be fit with other combinations of values (lower right panel) absolute magnitude absolute magnitude M 3M 5M.1 B.5 B 1 M 5. B cm 1 12 cm cm 1 2 time (days) 3 R M ej =6M E 51 =3B R = cm r g i time (days)