skip to main content
OSTI.GOV title logo U.S. Department of Energy
Office of Scientific and Technical Information

Title: Broad-lined Supernova 2016coi with a Helium Envelope

Abstract

We present the early-phase spectra and the light curves of the broad-lined (BL) supernova (SN) 2016coi from t = 7 to 67 days after the estimated explosion date. This SN was initially reported as a BL Type SN Ic (SN Ic-BL). However, we found that spectra up to t = 12 days exhibited the He i λ 5876, λ 6678, and λ 7065 absorption lines. We show that the smoothed and blueshifted spectra of normal SNe Ib are remarkably similar to the observed spectrum of SN 2016coi. The line velocities of SN 2016coi were similar to those of SNe Ic-BL and significantly faster than those of SNe Ib. Analyses of the line velocity and light curve suggest that the kinetic energy and the total ejecta mass of SN 2016coi are similar to those of SNe Ic-BL. Together with BL SNe 2009bb and 2012ap, for which the detection of He i was also reported, these SNe could be transitional objects between SNe Ic-BL and SNe Ib, and be classified as BL Type “Ib” SNe (SNe “Ib”-BL). Our work demonstrates the diversity of the outermost layer in BL SNe, which should be related to the variety of the evolutionary paths.

Authors:
 [1]; ;  [2];  [3];  [4]; ; ; ;  [5];  [6];  [7];  [8];  [9];  [10]; ; ; ; ;  [11];  [12] more »; « less
  1. Department of Physics, Faculty of Science and Engineering, Konan University, Okamoto, Kobe, Hyogo 658-8501 (Japan)
  2. Department of Physical Science, Hiroshima University, Kagamiyama 1-3-1, Higashi-Hiroshima 739-8526 (Japan)
  3. National Astronomical Observatory of Japan, National Institutes of Natural Sciences, Osawa, Mitaka, Tokyo 181-8588 (Japan)
  4. Department of Astronomy, Graduate School of Science, Kyoto University, Sakyo-ku, Kyoto 606-8502 (Japan)
  5. Nishi-Harima Astronomical Observatory, Center for Astronomy, University of Hyogo, 407-2 Nishigaichi, Sayo-cho, Sayo, Hyogo 679-5313 (Japan)
  6. Ishigakijima Astronomical Observatory, National Astronomical Observatory of Japan, National Institutes of Natural Sciences, 1024-1 Arakawa, Ishigaki, Okinawa 907-0024 (Japan)
  7. Institute of Astronomy, Graduate School of Science, The University of Tokyo, 2-21-1 Osawa, Mitaka, Tokyo 181-0015 (Japan)
  8. Department of Cosmosciences, Graduate School of Science, Hokkaido University, Kita 10 Nishi8, Kita-ku, Sapporo 060-0810 (Japan)
  9. Nobeyama Radio Observatory, National Astronomical Observatory of Japan, National Institutes of Natural Sciences, 462-2 Nobeyama, Minamimaki, Minamisaku, Nagano 384-1305 (Japan)
  10. Department of Astrophysics, Nagoya University, Chikusa-ku, Nagoya 464-8602 (Japan)
  11. Graduate School of Science and Engineering, Kagoshima University, 1-21-35 Korimoto, Kagoshima 890-0065 (Japan)
  12. Gunma Astronomical Observatory, Takayama, Gunma 377-0702 (Japan)
Publication Date:
OSTI Identifier:
22661345
Resource Type:
Journal Article
Resource Relation:
Journal Name: Astrophysical Journal; Journal Volume: 837; Journal Issue: 1; Other Information: Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
79 ASTROPHYSICS, COSMOLOGY AND ASTRONOMY; ABSORPTION; DETECTION; EXPLOSIONS; HELIUM; KINETIC ENERGY; MASS; SPECTRA; SUPERNOVAE; TYPE I SUPERNOVAE; VELOCITY; VISIBLE RADIATION

Citation Formats

Yamanaka, Masayuki, Nakaoka, Tatsuya, Kawabata, Miho, Tanaka, Masaomi, Maeda, Keiichi, Honda, Satoshi, Hosoya, Kensuke, Karita, Mayu, Morihana, Kumiko, Hanayama, Hidekazu, Morokuma, Tomoki, Imai, Masataka, Kinugasa, Kenzo, Murata, Katsuhiro L., Nishimori, Takefumi, Gima, Hirotaka, Ito, Ayano, Morikawa, Yuto, Murakami, Kotone, Hashimoto, Osamu, E-mail: yamanaka@center.konan-u.ac.jp, and and others. Broad-lined Supernova 2016coi with a Helium Envelope. United States: N. p., 2017. Web. doi:10.3847/1538-4357/AA5F57.
Yamanaka, Masayuki, Nakaoka, Tatsuya, Kawabata, Miho, Tanaka, Masaomi, Maeda, Keiichi, Honda, Satoshi, Hosoya, Kensuke, Karita, Mayu, Morihana, Kumiko, Hanayama, Hidekazu, Morokuma, Tomoki, Imai, Masataka, Kinugasa, Kenzo, Murata, Katsuhiro L., Nishimori, Takefumi, Gima, Hirotaka, Ito, Ayano, Morikawa, Yuto, Murakami, Kotone, Hashimoto, Osamu, E-mail: yamanaka@center.konan-u.ac.jp, & and others. Broad-lined Supernova 2016coi with a Helium Envelope. United States. doi:10.3847/1538-4357/AA5F57.
Yamanaka, Masayuki, Nakaoka, Tatsuya, Kawabata, Miho, Tanaka, Masaomi, Maeda, Keiichi, Honda, Satoshi, Hosoya, Kensuke, Karita, Mayu, Morihana, Kumiko, Hanayama, Hidekazu, Morokuma, Tomoki, Imai, Masataka, Kinugasa, Kenzo, Murata, Katsuhiro L., Nishimori, Takefumi, Gima, Hirotaka, Ito, Ayano, Morikawa, Yuto, Murakami, Kotone, Hashimoto, Osamu, E-mail: yamanaka@center.konan-u.ac.jp, and and others. Wed . "Broad-lined Supernova 2016coi with a Helium Envelope". United States. doi:10.3847/1538-4357/AA5F57.
@article{osti_22661345,
title = {Broad-lined Supernova 2016coi with a Helium Envelope},
author = {Yamanaka, Masayuki and Nakaoka, Tatsuya and Kawabata, Miho and Tanaka, Masaomi and Maeda, Keiichi and Honda, Satoshi and Hosoya, Kensuke and Karita, Mayu and Morihana, Kumiko and Hanayama, Hidekazu and Morokuma, Tomoki and Imai, Masataka and Kinugasa, Kenzo and Murata, Katsuhiro L. and Nishimori, Takefumi and Gima, Hirotaka and Ito, Ayano and Morikawa, Yuto and Murakami, Kotone and Hashimoto, Osamu, E-mail: yamanaka@center.konan-u.ac.jp and and others},
abstractNote = {We present the early-phase spectra and the light curves of the broad-lined (BL) supernova (SN) 2016coi from t = 7 to 67 days after the estimated explosion date. This SN was initially reported as a BL Type SN Ic (SN Ic-BL). However, we found that spectra up to t = 12 days exhibited the He i λ 5876, λ 6678, and λ 7065 absorption lines. We show that the smoothed and blueshifted spectra of normal SNe Ib are remarkably similar to the observed spectrum of SN 2016coi. The line velocities of SN 2016coi were similar to those of SNe Ic-BL and significantly faster than those of SNe Ib. Analyses of the line velocity and light curve suggest that the kinetic energy and the total ejecta mass of SN 2016coi are similar to those of SNe Ic-BL. Together with BL SNe 2009bb and 2012ap, for which the detection of He i was also reported, these SNe could be transitional objects between SNe Ic-BL and SNe Ib, and be classified as BL Type “Ib” SNe (SNe “Ib”-BL). Our work demonstrates the diversity of the outermost layer in BL SNe, which should be related to the variety of the evolutionary paths.},
doi = {10.3847/1538-4357/AA5F57},
journal = {Astrophysical Journal},
number = 1,
volume = 837,
place = {United States},
year = {Wed Mar 01 00:00:00 EST 2017},
month = {Wed Mar 01 00:00:00 EST 2017}
}
  • Models for the spectra and the light curve (LC), in the photospheric as well as in the late nebular phase, are used to infer the properties of the very radio-bright, broad-lined type IIb supernova (SN) 2003bg. Consistent fits to the LC and the spectral evolution are obtained with an explosion that ejected approx4 M {sub sun} of material with a kinetic energy of approx5 x 10{sup 51} erg. A thin layer of hydrogen, comprising approx0.05 M {sub sun}, is inferred to be present in the ejecta at the highest velocities (v approx> 9000 km s{sup -1}), while a thicker heliummore » layer, comprising approx1.25 M {sub sun}, was ejected at velocities between 6500 and 9000 km s{sup -1}. At lower velocities, heavier elements are present, including approx0.2 M {sub sun} of {sup 56}Ni that shape the LC and the late-time nebular spectra. These values suggest that the progenitor star had a mass of approx20-25 M {sub sun}, (comparable to, but maybe somewhat smaller than that of the progenitor of the X-ray flashes/SN 2008D). The rather broad-lined early spectra are the result of the presence of a small amount of material (approx0.03 M {sub sun}) at velocities >0.1c, which carries approx10% of the explosion kinetic energy. No clear signatures of a highly aspherical explosion are detected.« less
  • We report on our serendipitous pre-discovery detection and follow-up observations of the broad-lined Type Ic supernova (SN Ic) 2010ay at z = 0.067 imaged by the Pan-STARRS1 3{pi} survey just {approx}4 days after explosion. The supernova (SN) had a peak luminosity, M{sub R} Almost-Equal-To -20.2 mag, significantly more luminous than known GRB-SNe and one of the most luminous SNe Ib/c ever discovered. The absorption velocity of SN 2010ay is v{sub Si} Almost-Equal-To 19 Multiplication-Sign 10{sup 3} km s{sup -1} at {approx}40 days after explosion, 2-5 times higher than other broad-lined SNe and similar to the GRB-SN 2010bh at comparable epochs.more » Moreover, the velocity declines {approx}2 times slower than other SNe Ic-BL and GRB-SNe. Assuming that the optical emission is powered by radioactive decay, the peak magnitude implies the synthesis of an unusually large mass of {sup 56}Ni, M{sub Ni} = 0.9 M{sub Sun }. Applying scaling relations to the light curve, we estimate a total ejecta mass, M{sub ej} Almost-Equal-To 4.7 M{sub Sun }, and total kinetic energy, E{sub K} Almost-Equal-To 11 Multiplication-Sign 10{sup 51} erg. The ratio of M{sub Ni} to M{sub ej} is {approx}2 times as large for SN 2010ay as typical GRB-SNe and may suggest an additional energy reservoir. The metallicity (log (O/H){sub PP04} + 12 = 8.19) of the explosion site within the host galaxy places SN 2010ay in the low-metallicity regime populated by GRB-SNe, and {approx}0.5(0.2) dex lower than that typically measured for the host environments of normal (broad-lined) SNe Ic. We constrain any gamma-ray emission with E{sub {gamma}} {approx}< 6 Multiplication-Sign 10{sup 48} erg (25-150 keV), and our deep radio follow-up observations with the Expanded Very Large Array rule out relativistic ejecta with energy E {approx}> 10{sup 48} erg. We therefore rule out the association of a relativistic outflow like those that accompanied SN 1998bw and traditional long-duration gamma-ray bursts (GRBs), but we place less-stringent constraints on a weak afterglow like that seen from XRF 060218. If this SN did not harbor a GRB, these observations challenge the importance of progenitor metallicity for the production of relativistic ejecta and suggest that other parameters also play a key role.« less
  • Diffuse interstellar bands (DIBs) are absorption features observed in optical and near-infrared spectra that are thought to be associated with carbon-rich polyatomic molecules in interstellar gas. However, because the central wavelengths of these bands do not correspond to electronic transitions of any known atomic or molecular species, their nature has remained uncertain since their discovery almost a century ago. Here we report on unusually strong DIBs in optical spectra of the broad-lined Type Ic supernova SN 2012ap that exhibit changes in equivalent width over short (≲ 30 days) timescales. The 4428 Å and 6283 Å DIB features get weaker with time,more » whereas the 5780 Å feature shows a marginal increase. These nonuniform changes suggest that the supernova is interacting with a nearby source of DIBs and that the DIB carriers possess high ionization potentials, such as small cations or charged fullerenes. We conclude that moderate-resolution spectra of supernovae with DIB absorptions obtained within weeks of outburst could reveal unique information about the mass-loss environment of their progenitor systems and provide new constraints on the properties of DIB carriers.« less
  • Long-duration gamma-ray bursts (GRBs) at z < 1 are found in most cases to be accompanied by bright, broad-lined Type Ic supernovae (SNe Ic-BL). The highest-energy GRBs are mostly located at higher redshifts, where the associated SNe are hard to detect observationally. Here, we present early and late observations of the optical counterpart of the very energetic GRB 130427A. Despite its moderate redshift, z = 0.3399 ± 0.0002, GRB 130427A is at the high end of the GRB energy distribution, with an isotropic-equivalent energy release of E{sub iso} ∼ 9.6 × 10{sup 53} erg, more than an order of magnitudemore » more energetic than other GRBs with spectroscopically confirmed SNe. In our dense photometric monitoring, we detect excess flux in the host-subtracted r-band light curve, consistent with that expected from an emerging SN, ∼0.2 mag fainter than the prototypical SN 1998bw. A spectrum obtained around the time of the SN peak (16.7 days after the GRB) reveals broad undulations typical of SNe Ic-BL, confirming the presence of an SN, designated SN 2013cq. The spectral shape and early peak time are similar to those of the high expansion velocity SN 2010bh associated with GRB 100316D. Our findings demonstrate that high-energy, long-duration GRBs, commonly detected at high redshift, can also be associated with SNe Ic-BL, pointing to a common progenitor mechanism.« less