ANALYSIS OF THE EARLY-TIME OPTICAL SPECTRA OF SN 2011fe IN M101

Journal Article · Wed Jun 20 00:00:00 EDT 2012 · Astrophysical Journal Letters

DOI:https://doi.org/10.1088/2041-8205/752/2/L26· OSTI ID:22047746

Parrent, J T; Fesen, R A ^[1]; Howell, D A; Dilday, B ^[2]; Friesen, B; Baron, E ^[3]; Thomas, R C; Nugent, P ^[4]; Milisavljevic, D ^[5]; Bianco, F B; Bildsten, L ^[6]; Arcavi, I; Ben-Ami, S; Gal-Yam, A ^[7]; Bersier, D ^[8]; Bloom, J; Cenko, S B; Filippenko, A V ^[9]; Cao, Y ^[10]; Kasliwal, M M ^[11] ; others, and

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1. 6127 Wilder Lab, Department of Physics and Astronomy, Dartmouth College, Hanover, NH 03755 (United States)
2. Las Cumbres Observatory Global Telescope Network, Goleta, CA 93117 (United States)
3. Homer L. Dodge Department of Physics and Astronomy, University of Oklahoma, 440 W Brooks, Norman, OK 73019 (United States)
4. Physics Division, Lawrence Berkeley National Laboratory, 1 Cyclotron Road, Berkeley, CA 94720 (United States)
5. Harvard-Smithsonian Center for Astrophysics, 60 Garden St., Cambridge, MA 02138 (United States)
6. Department of Physics, University of California, Santa Barbara, Santa Barbara, CA 93117 (United States)
7. Department of Particle Physics and Astrophysics, The Weizmann Institute of Science, Rehovot 76100 (Israel)
8. Astrophysics Research Institute, Liverpool John Moores University, Birkenhead CH41 1LD (United Kingdom)
9. Department of Astronomy, University of California, Berkeley, CA 94720 (United States)
10. Cahill Center for Astronomy and Astrophysics, California Institute of Technology, 1200 E California Blvd., Pasadena, CA 91125 (United States)
11. Observatories of the Carnegie Institution for Science, 813 Santa Barbara Street, Pasadena, CA 91101 (United States)

The nearby Type Ia supernova (SN Ia) SN 2011fe in M101 (cz = 241 km s{sup -1}) provides a unique opportunity to study the early evolution of a 'normal' SN Ia, its compositional structure, and its elusive progenitor system. We present 18 high signal-to-noise spectra of SN 2011fe during its first month beginning 1.2 days post-explosion and with an average cadence of 1.8 days. This gives a clear picture of how various line-forming species are distributed within the outer layers of the ejecta, including that of unburned material (C+O). We follow the evolution of C II absorption features until they diminish near maximum light, showing overlapping regions of burned and unburned material between ejection velocities of 10,000 and 16,000 km s{sup -1}. This supports the notion that incomplete burning, in addition to progenitor scenarios, is a relevant source of spectroscopic diversity among SNe Ia. The observed evolution of the highly Doppler-shifted O I {lambda}7774 absorption features detected within 5 days post-explosion indicates the presence of O I with expansion velocities from 11,500 to 21,000 km s{sup -1}. The fact that some O I is present above C II suggests that SN 2011fe may have had an appreciable amount of unburned oxygen within the outer layers of the ejecta.

• OSTI ID: 22047746
• Journal Information: Astrophysical Journal Letters, Vol. 752, Issue 2; Other Information: Country of input: International Atomic Energy Agency (IAEA); ISSN 2041-8205
• Country of Publication: United States
• Language: English

Related Subjects

79 ASTROPHYSICS
COSMOLOGY AND ASTRONOMY
ABSORPTION
ABSORPTION SPECTRA
ASTRONOMY
ASTROPHYSICS
DOPPLER EFFECT
EMISSION SPECTRA
LAYERS
NOISE
OXYGEN
SIGNALS
STAR EVOLUTION
SUPERNOVAE
VELOCITY
VISIBLE RADIATION