Persistent C II Absorption in the Normal Type Ia Supernova 2002fk

• Published in: arXiv.org 2014-05
• Main Authors: Cartier, Régis, Hamuy, Mario, Pignata, Giuliano, ster, Francisco, Zelaya, Paula, Gaston Folatelli, Phillips, Mark M, Morrell, Nidia, Krisciunas, Kevin, Suntzeff, Nicholas B, Clocchiatti, Alejandro, Coppi, Paolo, Contreras, Carlos, Roth, Miguel, Koviak, Kathleen, Maza, José, González, Luis, González, Sergio, Huerta, Leonor
• Format: Article
• Language: English
• Subjects: Light curve; Line spectra; Photometry; Velocity gradient; Viewing
• ISSN: 2331-8422
• DOI: 10.48550/arxiv.1312.3342

We present well-sampled \(UBVRIJHK\) photometry of SN 2002fk starting 12 days before maximum light through 122 days after peak brightness, along with a series of 15 optical spectra from -4 to +95 days since maximum. Our observations show the presence of C II lines in the early-time spectra of SN 2002fk, expanding at ~11,000 km s\(^{-1}~\) and persisting until ~8 days past maximum light with a velocity of \(\sim\)9,000 km s\(^{-1}~\). SN 2002fk is characterized by a small velocity gradient of \(\dot v_{Si~II}=26\) km s\(^{-1}\) day\(^{-1}\), possibly caused by an off-center explosion with the ignition region oriented towards the observer. The connection between viewing angle of an off-center explosion and the presence of C II in the early time spectrum suggests that the observation of C II could be also due to a viewing angle effect. Adopting the Cepheid distance to NGC 1309 we provide the first \(H_{0}\) value based on near-IR measurements of a Type Ia supernova between 63.0\(\pm\) 0.8 (\(\pm\) 2.8 systematic) and 66.7\(\pm\)1.0 (\(\pm\) 3.5 systematic) km/s/Mpc, depending on the absolute magnitude/decline rate relationship adopted. It appears that the near-IR yields somewhat lower (6-9 %) \(H_0\) values than the optical. It is essential to further examine this issue by (1) expanding the sample of high-quality near-IR light curves of SNe in the Hubble flow, and (2) increasing the number of nearby SNe with near-IR SN light curves and precise Cepheid distances, which affords the promise to deliver a more precise determination of \(H_0\).