Статья

CALCIUM-RICH GAP TRANSIENTS IN THE REMOTE OUTSKIRTS OF GALAXIES

M. M. KasliwalCahill Center for Astrophysics, California Institute of Technology, Pasadena, CA 91125, USAS. R. KulkarniCahill Center for Astrophysics, California Institute of Technology, Pasadena, CA 91125, USAA. Gal‐YamBenoziyo Center for Astrophysics, Faculty of Physics, The Weizmann Institute of Science, Rehovot 76100, IsraelP. NugentComputational Cosmology Center, Lawrence Berkeley National Laboratory, 1 Cyclotron Road, Berkeley, CA 94720, USAM. SullivanDepartment of Physics, Oxford University, Oxford OX1 3RH, UKLars BildstenDepartment of Physics, University of California, Santa Barbara, CA 93106, USAO. YaronBenoziyo Center for Astrophysics, Faculty of Physics, The Weizmann Institute of Science, Rehovot 76100, IsraelHagai B. PeretsHarvard-Smithsonian Center for Astrophysics, 60 Garden St., Cambridge, MA 02338, USAIair ArcaviBenoziyo Center for Astrophysics, Faculty of Physics, The Weizmann Institute of Science, Rehovot 76100, IsraelSagi Ben-AmiBenoziyo Center for Astrophysics, Faculty of Physics, The Weizmann Institute of Science, Rehovot 76100, IsraelV. BhaleraoCahill Center for Astrophysics, California Institute of Technology, Pasadena, CA 91125, USAJ. S. BloomDepartment of Astronomy, University of California, Berkeley, CA 94720-3411, USAS. B. CenkoDepartment of Astronomy, University of California, Berkeley, CA 94720-3411, USAA. V. FilippenkoDepartment of Astronomy, University of California, Berkeley, CA 94720-3411, USAD. A. FrailNational Radio Astronomy Observatory, Array Operations Center, Socorro, NM 87801, USAM. GaneshalingamDepartment of Astronomy, University of California, Berkeley, CA 94720-3411, USAA. HoreshCahill Center for Astrophysics, California Institute of Technology, Pasadena, CA 91125, USAD. A. HowellKavli Institute for Theoretical Physics, University of California, Santa Barbara, CA 93106, USANicholas M. LawDunlap Institute for Astronomy and Astrophysics, University of Toronto, 50 St. George Street, Toronto M5S 3H4, Ontario, CanadaDouglas C. LeonardDepartment of Astronomy, San Diego State University, San Diego, CA 92182, USAWeidong LiDepartment of Astronomy, University of California, Berkeley, CA 94720-3411, USAE. O. OfekBenoziyo Center for Astrophysics, Faculty of Physics, The Weizmann Institute of Science, Rehovot 76100, IsraelDavid PolishookBenoziyo Center for Astrophysics, Faculty of Physics, The Weizmann Institute of Science, Rehovot 76100, IsraelD. PoznanskiSchool of Physics and Astronomy, Tel-Aviv University, Tel Aviv 69978, IsraelR. M. QuimbyCahill Center for Astrophysics, California Institute of Technology, Pasadena, CA 91125, USAJ. M. SilvermanDepartment of Astronomy, University of California, Berkeley, CA 94720-3411, USAA. SternbergBenoziyo Center for Astrophysics, Faculty of Physics, The Weizmann Institute of Science, Rehovot 76100, IsraelD. XuBenoziyo Center for Astrophysics, Faculty of Physics, The Weizmann Institute of Science, Rehovot 76100, Israel

2012en

ABI

Аннотация

From the first two seasons of the Palomar Transient Factory, we identify three peculiar transients (PTF09dav, PTF10iuv, PTF11bij) with five distinguishing characteristics: peak luminosity in the gap between novae and supernovae (M_R ≈ - 15.5 to -16.5), rapid photometric evolution (t_(rise) ≈12-15 days), large photospheric velocities (≈6000 to 11000 km s^(-1)), early spectroscopic evolution into nebular phase (≈1 to 3 months) and peculiar nebular spectra dominated by Calcium. We also culled the extensive decade-long Lick Observatory Supernova Search database and identified an additional member of this group, SN 2007ke. Our choice of photometric and spectroscopic properties was motivated by SN 2005E (Perets et al. 2010). To our surprise, as in the case of SN 2005E, all four members of this group are also clearly offset from the bulk of their host galaxy. Given the well-sampled early and late-time light curves, we derive ejecta masses in the range of 0.4--0.7 M_⊙. Spectroscopically, we find that there may be a diversity in the photospheric phase, but the commonality is in the unusual nebular spectra. Our extensive follow-up observations rule out standard thermonuclear and standard core-collapse explosions for this class of "Calcium-rich gap" transients. If the progenitor is a white dwarf, we are likely seeing a detonation of the white dwarf core and perhaps, even shock-front interaction with a previously ejected nova shell. In the less likely scenario of a massive star progenitor, a very non-standard channel specific to a low-metallicity environment needs to be invoked (e.g., ejecta fallback leading to black hole formation). Detection (or lack thereof) of a faint underlying host (dwarf galaxy, cluster) will provide a crucial and decisive diagnostic to choose between these alternatives.

Перевод пока недоступен

Идентификаторы

DOI: 10.1088/0004-637x/755/2/161

Цитирования и источники

Цитирований: 2Использованных источников: 0

Показатели — AkademScholar