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The broad-lined type ic sn 2012ap and the nature of relativistic supernovae lacking a gamma-ray burst detection
| Content Provider | NASA Technical Reports Server (NTRS) |
|---|---|
| Author | Milisavljevic, D. Mazzali, P. Fesen, R. A. Margutti, R. Sanders, N. E. Cenko, S. B. Maeda, K. Silverman, J. M. Soderberg, A. M. Parrent, J. T. |
| Copyright Year | 2014 |
| Description | We present ultraviolet, optical, and near-infrared observations of SN2012ap, a broad-lined Type Ic supernova in the galaxy NGC 1729 that produced a relativistic and rapidly decelerating outflow without a gamma-ray burst signature. Photometry and spectroscopy follow the flux evolution from â13 to +272 days past the B-band maximum of â17.4 +/- 0.5 mag. The spectra are dominated by Fe II, O I, and Ca II absorption lines at ejecta velocities of v approx. 20,000 km s(exp. â1) that change slowly over time. Other spectral absorption lines are consistent with contributions from photospheric He I, and hydrogen may also be present at higher velocities (v approx. greater than 27,000 km s(exp. â1)). We use these observations to estimate explosion properties and derive a total ejecta mass of 2.7 Solar mass, a kinetic energy of 1.0Ã1052 erg, and a (56)Ni mass of 0.1â0.2 Solar mass. Nebular spectra (t > 200 d) exhibit an asymmetric double-peaked [O I] lambda lambda 6300, 6364 emission profile that we associate with absorption in the supernova interior, although toroidal ejecta geometry is an alternative explanation. SN2012ap joins SN2009bb as another exceptional supernova that shows evidence for a central engine (e.g., black-hole accretion or magnetar) capable of launching a non-negligible portion of ejecta to relativistic velocities without a coincident gamma-ray burst detection. Defining attributes of their progenitor systems may be related to notable properties including above-average environmental metallicities of Z approx. greater than Solar Z, moderate to high levels of host-galaxy extinction (E(B âV ) > 0.4 mag), detection of high-velocity helium at early epochs, and a high relative flux ratio of [Ca II]/[O I] > 1 at nebular epochs. These events support the notion that jet activity at various energy scales may be present in a wide range of supernovae. |
| File Size | 1770867 |
| Page Count | 16 |
| File Format | |
| Alternate Webpage(s) | http://archive.org/details/NASA_NTRS_Archive_20160005814 |
| Archival Resource Key | ark:/13960/t0rr6v92t |
| Language | English |
| Publisher Date | 2014-08-11 |
| Access Restriction | Open |
| Subject Keyword | Nature Supervova Lacking Solar Spectra Optical Measurement Ejecta Galaxies Supernovae Stellar Mass Metallicity Relativistic Velocity Explosions Absorption Spectra Line Spectra Gamma Ray Bursts Ntrs Nasa Technical Reports Server (ntrs) Nasa Technical Reports Server Aerodynamics Aircraft Aerospace Engineering Aerospace Aeronautic Space Science |
| Content Type | Text |
| Resource Type | Article |
