Статья

TYPE Ia SUPERNOVA CARBON FOOTPRINTS

R. C. ThomasComputational Cosmology Center, Computational Research Division, Lawrence Berkeley National Laboratory, 1 Cyclotron Road MS 50B-4206, Berkeley, CA 94611, USAG. AlderingPhysics Division, Lawrence Berkeley National Laboratory, 1 Cyclotron Road, Berkeley, CA 94720, USAP. AntilogusLaboratoire de Physique Nucléaire et des Hautes Énergies, Université Pierre et Marie Curie Paris 6, Université Paris Diderot Paris 7, CNRS-IN2P3, 4 place Jussieu, 75252 Paris Cedex 05, FranceC. AragonPhysics Division, Lawrence Berkeley National Laboratory, 1 Cyclotron Road, Berkeley, CA 94720, USAS. BaileyPhysics Division, Lawrence Berkeley National Laboratory, 1 Cyclotron Road, Berkeley, CA 94720, USAC. BaltayDepartment of Physics, Yale University, New Haven, CT 06250-8121, USAS. BongardLaboratoire de Physique Nucléaire et des Hautes Énergies, Université Pierre et Marie Curie Paris 6, Université Paris Diderot Paris 7, CNRS-IN2P3, 4 place Jussieu, 75252 Paris Cedex 05, FranceC. ButonPhysikalisches Institut, Universität Bonn, Nußallee 12, 53115 Bonn, GermanyA. CantoLaboratoire de Physique Nucléaire et des Hautes Énergies, Université Pierre et Marie Curie Paris 6, Université Paris Diderot Paris 7, CNRS-IN2P3, 4 place Jussieu, 75252 Paris Cedex 05, FranceM. ChildressDepartment of Physics, University of California Berkeley, 366 LeConte Hall MC 7300, Berkeley, CA 94720-7300, USAN. ChotardUniversité de Lyon, F-69622 Lyon, FranceY. CopinUniversité de Lyon, F-69622 Lyon, FranceH. K. FakhouriDepartment of Physics, University of California Berkeley, 366 LeConte Hall MC 7300, Berkeley, CA 94720-7300, USAE. GanglerUniversité de Lyon, F-69622 Lyon, FranceE. Y. HsiaoPhysics Division, Lawrence Berkeley National Laboratory, 1 Cyclotron Road, Berkeley, CA 94720, USAM. KerschhagglPhysikalisches Institut, Universität Bonn, Nußallee 12, 53115 Bonn, GermanyM. KowalskiPhysikalisches Institut, Universität Bonn, Nußallee 12, 53115 Bonn, GermanyS. LokenPhysics Division, Lawrence Berkeley National Laboratory, 1 Cyclotron Road, Berkeley, CA 94720, USAP. NugentComputational Cosmology Center, Computational Research Division, Lawrence Berkeley National Laboratory, 1 Cyclotron Road MS 50B-4206, Berkeley, CA 94611, USAK. PaechPhysikalisches Institut, Universität Bonn, Nußallee 12, 53115 Bonn, GermanyR. PainLaboratoire de Physique Nucléaire et des Hautes Énergies, Université Pierre et Marie Curie Paris 6, Université Paris Diderot Paris 7, CNRS-IN2P3, 4 place Jussieu, 75252 Paris Cedex 05, FranceE. PecontalUniversité de Lyon 1, Villeurbanne, Lyon, FranceR. PereiraUniversité de Lyon, F-69622 Lyon, FranceS. PerlmutterDepartment of Physics, University of California Berkeley, 366 LeConte Hall MC 7300, Berkeley, CA 94720-7300, USAD. RabinowitzDepartment of Physics, Yale University, New Haven, CT 06250-8121, USAM. RigaultUniversité de Lyon, F-69622 Lyon, FranceD. RubinDepartment of Physics, University of California Berkeley, 366 LeConte Hall MC 7300, Berkeley, CA 94720-7300, USAK. RungePhysics Division, Lawrence Berkeley National Laboratory, 1 Cyclotron Road, Berkeley, CA 94720, USAR. ScalzoCNRS/IN2P3, Institut de Physique Nucléaire de Lyon, Lyon, FranceG. SmadjaUniversité de Lyon, F-69622 Lyon, FranceC. TaoCentre de Recherche Astronomique de Lyon, Université Lyon 1, 9 Avenue Charles André, 69561 Saint Genis Laval Cedex, FranceB. A. WeaverCentre de Physique des Particules de Marseille, 163, Avenue de Luminy - Case 902 - 13288 Marseille Cedex 09, FranceC. WuTsinghua Center for Astrophysics, Tsinghua University, Beijing 100084, China(The Nearby Supernova Factory)P. J. BrownCenter for Cosmology and Particle Physics, New York University, 4 Washington Place, New York, NY 10003, USAP. A. MilneNational Astronomical Observatories

2011en

ABI

Аннотация

We present convincing evidence of unburned carbon at photospheric velocities in new observations of five TypeIa supernovae (SNe Ia) obtained by the Nearby Supernova Factory. These SNe are identified by examining 346 spectra from 124 SNe obtained before +2.5days relative to maximum. Detections are based on the presence of relatively strong C II λ6580 absorption "notches" in multiple spectra of each SN, aided by automated fitting with the SYNAPPS code. Four of the five SNe in question are otherwise spectroscopically unremarkable, with ions and ejection velocities typical of SNe Ia, but spectra of the fifth exhibit high-velocity (v > 20, 000kms-1) Si II and Ca II features. On the other hand, the light curve properties are preferentially grouped, strongly suggesting a connection between carbon-positivity and broadband light curve/color behavior: three of the five have relatively narrow light curves but also blue colors and a fourth may be a dust-reddened member of this family. Accounting for signal to noise and phase, we estimate that 22+10- 6% of SNe Ia exhibit spectroscopic C II signatures as late as -5days with respect to maximum. We place these new objects in the context of previously recognized carbon-positive SNe Ia and consider reasonable scenarios seeking to explain a physical connection between light curve properties and the presence of photospheric carbon. We also examine the detailed evolution of the detected carbon signatures and the surrounding wavelength regions to shed light on the distribution of carbon in the ejecta. Our ability to reconstruct the C II λ6580 feature in detail under the assumption of purely spherical symmetry casts doubt on a "carbon blobs" hypothesis, but does not rule out all asymmetric models. A low volume filling factor for carbon, combined with line-of-sight effects, seems unlikely to explain the scarcity of detected carbon in SNe Ia by itself.

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Идентификаторы

DOI: 10.1088/0004-637x/743/1/27

Цитирования и источники

Цитирований: 2Использованных источников: 0

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