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

Title: Spectroscopic Observations and Analysis of the Unusual Type Ia SN1999ac

Abstract

The authors present optical spectra of the peculiar Type Ia supernova (SN Ia) 1999ac. The data extend from -15 to +42 days with respect to B-band maximum and reveal an event that is unusual in several respects. prior to B-band maximum, the spectra resemble those of SN 1999aa, a slowly declining event, but possess stronger Si II and Ca II signatures (more characteristic of a spectroscopically normal SN). Spectra after B-band maximum appear more normal. The expansion velocities inferred from the Iron lines appear to be lower than average; whereas, the expansion velocity inferred from Calcium H and K are higher than average. The expansion velocities inferred from the Iron lines appear to be lower than average; whereas, the expansion velocity inferred from Calcium H and K are higher than average. The expansion velocities inferred from Si II are among the slowest ever observed, though SN 1999ac is not particularly dim. The analysis of the parameters v{sub 10}(Si II), R(Si II), v, and {Delta}m{sub 15} further underlines the unique characteristics of SN 1999ac. They find convincing evidence of C II {lambda}6580 in the day -15 spectrum with ejection velocity v > 16,000 km s{sup -1}, but this signature disappears bymore » day -9. This rapid evolution at early times highlights the importance of extremely early-time spectroscopy.« less

Authors:
; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; more »; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; « less
Publication Date:
Research Org.:
COLLABORATION - U. ofParis
OSTI Identifier:
893063
Report Number(s):
LBNL-58301
R&D Project: PSUOPS; BnR: KA1301020; TRN: US0605922
DOE Contract Number:  
DE-AC02-05CH11231
Resource Type:
Journal Article
Journal Name:
The Astronomical Journal
Additional Journal Information:
Journal Volume: 130; Journal Issue: 4; Related Information: Journal Publication Date: 10/2005
Country of Publication:
United States
Language:
English
Subject:
72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS; CALCIUM; IRON; SPECTRA; SPECTROSCOPY; VELOCITY; Supernovae

Citation Formats

Garavini, G, Aldering, G, Amadon, A, Amanullah, R, Astier, P, Balland, C, Blanc, G, Conley, A, Dahlen, T, Deustua, S E, Ellis, R, Fabbro, S, Fadeyev, V, Fan, X, Folatelli, G, Frye, B, Gates, E L, Gibbons, R, Goldhaber, G, Goldman, B, Goobar, A, Groom, D E, Haissinski, J, Hardin, D, Hook, I, Howell, D A, Kent, S, Kim, A G, Knop, R A, Kowalski, M, Kuznetsova, N, Lee, B C, Lidman, C, Mendez, J, Miller, G J, Moniez, M, Mouchet, M, Mourao, A, Newberg, H, Nobili, S, Nugent, P E, Pain, R, Perdereau, O, Perlmutter, S, Quimby, R, Regnault, N, Rich, J, Richards, G T, Ruiz-Lapuente, P, Schaefer, B E, Schahmaneche, K, Smith, E, Spadafora, A L, Stanishev, V, Thomas, R C, Walton, N A, Wang, L, and Wood-Vasey, W M. Spectroscopic Observations and Analysis of the Unusual Type Ia SN1999ac. United States: N. p., 2005. Web.
Garavini, G, Aldering, G, Amadon, A, Amanullah, R, Astier, P, Balland, C, Blanc, G, Conley, A, Dahlen, T, Deustua, S E, Ellis, R, Fabbro, S, Fadeyev, V, Fan, X, Folatelli, G, Frye, B, Gates, E L, Gibbons, R, Goldhaber, G, Goldman, B, Goobar, A, Groom, D E, Haissinski, J, Hardin, D, Hook, I, Howell, D A, Kent, S, Kim, A G, Knop, R A, Kowalski, M, Kuznetsova, N, Lee, B C, Lidman, C, Mendez, J, Miller, G J, Moniez, M, Mouchet, M, Mourao, A, Newberg, H, Nobili, S, Nugent, P E, Pain, R, Perdereau, O, Perlmutter, S, Quimby, R, Regnault, N, Rich, J, Richards, G T, Ruiz-Lapuente, P, Schaefer, B E, Schahmaneche, K, Smith, E, Spadafora, A L, Stanishev, V, Thomas, R C, Walton, N A, Wang, L, & Wood-Vasey, W M. Spectroscopic Observations and Analysis of the Unusual Type Ia SN1999ac. United States.
Garavini, G, Aldering, G, Amadon, A, Amanullah, R, Astier, P, Balland, C, Blanc, G, Conley, A, Dahlen, T, Deustua, S E, Ellis, R, Fabbro, S, Fadeyev, V, Fan, X, Folatelli, G, Frye, B, Gates, E L, Gibbons, R, Goldhaber, G, Goldman, B, Goobar, A, Groom, D E, Haissinski, J, Hardin, D, Hook, I, Howell, D A, Kent, S, Kim, A G, Knop, R A, Kowalski, M, Kuznetsova, N, Lee, B C, Lidman, C, Mendez, J, Miller, G J, Moniez, M, Mouchet, M, Mourao, A, Newberg, H, Nobili, S, Nugent, P E, Pain, R, Perdereau, O, Perlmutter, S, Quimby, R, Regnault, N, Rich, J, Richards, G T, Ruiz-Lapuente, P, Schaefer, B E, Schahmaneche, K, Smith, E, Spadafora, A L, Stanishev, V, Thomas, R C, Walton, N A, Wang, L, and Wood-Vasey, W M. 2005. "Spectroscopic Observations and Analysis of the Unusual Type Ia SN1999ac". United States. https://www.osti.gov/servlets/purl/893063.
@article{osti_893063,
title = {Spectroscopic Observations and Analysis of the Unusual Type Ia SN1999ac},
author = {Garavini, G and Aldering, G and Amadon, A and Amanullah, R and Astier, P and Balland, C and Blanc, G and Conley, A and Dahlen, T and Deustua, S E and Ellis, R and Fabbro, S and Fadeyev, V and Fan, X and Folatelli, G and Frye, B and Gates, E L and Gibbons, R and Goldhaber, G and Goldman, B and Goobar, A and Groom, D E and Haissinski, J and Hardin, D and Hook, I and Howell, D A and Kent, S and Kim, A G and Knop, R A and Kowalski, M and Kuznetsova, N and Lee, B C and Lidman, C and Mendez, J and Miller, G J and Moniez, M and Mouchet, M and Mourao, A and Newberg, H and Nobili, S and Nugent, P E and Pain, R and Perdereau, O and Perlmutter, S and Quimby, R and Regnault, N and Rich, J and Richards, G T and Ruiz-Lapuente, P and Schaefer, B E and Schahmaneche, K and Smith, E and Spadafora, A L and Stanishev, V and Thomas, R C and Walton, N A and Wang, L and Wood-Vasey, W M},
abstractNote = {The authors present optical spectra of the peculiar Type Ia supernova (SN Ia) 1999ac. The data extend from -15 to +42 days with respect to B-band maximum and reveal an event that is unusual in several respects. prior to B-band maximum, the spectra resemble those of SN 1999aa, a slowly declining event, but possess stronger Si II and Ca II signatures (more characteristic of a spectroscopically normal SN). Spectra after B-band maximum appear more normal. The expansion velocities inferred from the Iron lines appear to be lower than average; whereas, the expansion velocity inferred from Calcium H and K are higher than average. The expansion velocities inferred from the Iron lines appear to be lower than average; whereas, the expansion velocity inferred from Calcium H and K are higher than average. The expansion velocities inferred from Si II are among the slowest ever observed, though SN 1999ac is not particularly dim. The analysis of the parameters v{sub 10}(Si II), R(Si II), v, and {Delta}m{sub 15} further underlines the unique characteristics of SN 1999ac. They find convincing evidence of C II {lambda}6580 in the day -15 spectrum with ejection velocity v > 16,000 km s{sup -1}, but this signature disappears by day -9. This rapid evolution at early times highlights the importance of extremely early-time spectroscopy.},
doi = {},
url = {https://www.osti.gov/biblio/893063}, journal = {The Astronomical Journal},
number = 4,
volume = 130,
place = {United States},
year = {Tue Jul 12 00:00:00 EDT 2005},
month = {Tue Jul 12 00:00:00 EDT 2005}
}