SUPER-LUMINOUS TYPE Ic SUPERNOVAE: CATCHING A MAGNETAR BY THE TAIL

Journal Article · Thu Jun 20 00:00:00 EDT 2013 · Astrophysical Journal

DOI:https://doi.org/10.1088/0004-637X/770/2/128· OSTI ID:22127068

Inserra, C.; Smartt, S. J.; Jerkstrand, A.; Fraser, M.; Wright, D.; Smith, K.; Chen, T. -W.; Kotak, R.; Nicholl, M. ^[1]; Valenti, S. ^[2]; Pastorello, A.; Benetti, S. ^[3]; Bresolin, F.; Kudritzki, R. P.; Burgett, W. S.; Chambers, K. C.; Flewelling, H. ^[4]; Botticella, M. T. ^[5]; Ergon, M. ^[6]; Fynbo, J. P. U., ^[7] ; others, and

---

1. Astrophysics Research Centre, School of Mathematics and Physics, Queens University Belfast, Belfast BT7 1NN (United Kingdom)
2. Las Cumbres Observatory Global Telescope Network, 6740 Cortona Dr., Suite 102 Goleta, CA 93117 (United States)
3. INAF, Osservatorio Astronomico di Padova, vicolo dell'Osservatorio 5, I-35122 Padova (Italy)
4. Institute of Astronomy, University of Hawaii, 2680 Woodlawn Drive, Honolulu, HI 96822 (United States)
5. INAF-Osservatorio Astronomico di Capodimonte, Salita Moiariello 16, I-80131 Napoli (Italy)
6. The Oskar Klein Centre, Department of Astronomy, AlbaNova, Stockholm University, SE-10691 Stockholm (Sweden)
7. Dark Cosmology Centre, Niels Bohr Institute, University of Copenhagen, DK-2100 Copenhagen (Denmark)

We report extensive observational data for five of the lowest redshift Super-Luminous Type Ic Supernovae (SL-SNe Ic) discovered to date, namely, PTF10hgi, SN2011ke, PTF11rks, SN2011kf, and SN2012il. Photometric imaging of the transients at +50 to +230 days after peak combined with host galaxy subtraction reveals a luminous tail phase for four of these SL-SNe. A high-resolution, optical, and near-infrared spectrum from xshooter provides detection of a broad He I {lambda}10830 emission line in the spectrum (+50 days) of SN2012il, revealing that at least some SL-SNe Ic are not completely helium-free. At first sight, the tail luminosity decline rates that we measure are consistent with the radioactive decay of {sup 56}Co, and would require 1-4 M{sub Sun} of {sup 56}Ni to produce the luminosity. These {sup 56}Ni masses cannot be made consistent with the short diffusion times at peak, and indeed are insufficient to power the peak luminosity. We instead favor energy deposition by newborn magnetars as the power source for these objects. A semi-analytical diffusion model with energy input from the spin-down of a magnetar reproduces the extensive light curve data well. The model predictions of ejecta velocities and temperatures which are required are in reasonable agreement with those determined from our observations. We derive magnetar energies of 0.4 {approx}< E(10{sup 51} erg) {approx}< 6.9 and ejecta masses of 2.3 {approx}< M{sub ej}(M{sub Sun }) {approx}< 8.6. The sample of five SL-SNe Ic presented here, combined with SN 2010gx-the best sampled SL-SNe Ic so far-points toward an explosion driven by a magnetar as a viable explanation for all SL-SNe Ic.

• OSTI ID: 22127068
• Journal Information: Astrophysical Journal, Journal Name: Astrophysical Journal Journal Issue: 2 Vol. 770; ISSN ASJOAB; ISSN 0004-637X
• Country of Publication: United States
• Language: English

Related Subjects

79 ASTRONOMY AND ASTROPHYSICS
COBALT 56
DETECTION
DIAGRAMS
ENERGY ABSORPTION
ENERGY LOSSES
GALAXIES
HELIUM
INFRARED SPECTRA
LUMINOSITY
MASS
NICKEL 56
NUCLEAR DECAY
PEAKS
RED SHIFT
SPIN
SUPERNOVAE