Abstract
We present near-infrared (NIR) spectra for Type la supernovae at epochs of 13 to 338 d after maximum blue light. Some contemporary optical spectra are also shown. All the NIR spectra exhibit considerable structure throughout the J, H and K bands. In particular, they exhibit a flux 'deficit' in the J band which persists as late as 175 d. This is responsible for the well-known red J-H colour. To identify the emission features and test the 56Ni hypothesis for the explosion and subsequent light curve, we compare the NIR and optical nebular-phase data with a simple non-LTE nebular spectral model. We find that many of the spectral features are due to iron-group elements, and that the J-band deficit is due to a lack of emission lines from species that dominate the rest of the IR/optical spectrum. Nevertheless, some emission is unaccounted for, possibly due to inaccuracies in the cobalt atomic data. For some supernovae, blueshifts of 1000-3000 km s -1 are seen in infrared and optical features at 3 months. We suggest that this is due to clumping in the ejecta. The evolution of the cobalt/iron mass ratio indicates that 56Co-decay dominates the abundances of these elements. The absolute masses of iron-group elements which we derive support the basic thermonuclear explosion scenario for Type la supernovae. A core-collapse origin is less consistent with our data.
| Original language | English (US) |
|---|---|
| Pages (from-to) | 663-679 |
| Number of pages | 17 |
| Journal | Monthly Notices of the Royal Astronomical Society |
| Volume | 290 |
| Issue number | 4 |
| State | Published - 1997 |
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Keywords
- Infrared: stars
- Stars: general
- Supernovae: general
ASJC Scopus subject areas
- Space and Planetary Science
Cite this
Infrared and optical spectroscopy of Type Ia supernovae in the nebular phase. / Bowers, E. J C; Meikle, W. P S; Geballe, T. R.; Walton, N. A.; Pinto, Philip A; Dhillon, V. S.; Howell, S. B.; Harrop-Allin, M. K.
In: Monthly Notices of the Royal Astronomical Society, Vol. 290, No. 4, 1997, p. 663-679.Research output: Contribution to journal › Article
}
TY - JOUR
T1 - Infrared and optical spectroscopy of Type Ia supernovae in the nebular phase
AU - Bowers, E. J C
AU - Meikle, W. P S
AU - Geballe, T. R.
AU - Walton, N. A.
AU - Pinto, Philip A
AU - Dhillon, V. S.
AU - Howell, S. B.
AU - Harrop-Allin, M. K.
PY - 1997
Y1 - 1997
N2 - We present near-infrared (NIR) spectra for Type la supernovae at epochs of 13 to 338 d after maximum blue light. Some contemporary optical spectra are also shown. All the NIR spectra exhibit considerable structure throughout the J, H and K bands. In particular, they exhibit a flux 'deficit' in the J band which persists as late as 175 d. This is responsible for the well-known red J-H colour. To identify the emission features and test the 56Ni hypothesis for the explosion and subsequent light curve, we compare the NIR and optical nebular-phase data with a simple non-LTE nebular spectral model. We find that many of the spectral features are due to iron-group elements, and that the J-band deficit is due to a lack of emission lines from species that dominate the rest of the IR/optical spectrum. Nevertheless, some emission is unaccounted for, possibly due to inaccuracies in the cobalt atomic data. For some supernovae, blueshifts of 1000-3000 km s -1 are seen in infrared and optical features at 3 months. We suggest that this is due to clumping in the ejecta. The evolution of the cobalt/iron mass ratio indicates that 56Co-decay dominates the abundances of these elements. The absolute masses of iron-group elements which we derive support the basic thermonuclear explosion scenario for Type la supernovae. A core-collapse origin is less consistent with our data.
AB - We present near-infrared (NIR) spectra for Type la supernovae at epochs of 13 to 338 d after maximum blue light. Some contemporary optical spectra are also shown. All the NIR spectra exhibit considerable structure throughout the J, H and K bands. In particular, they exhibit a flux 'deficit' in the J band which persists as late as 175 d. This is responsible for the well-known red J-H colour. To identify the emission features and test the 56Ni hypothesis for the explosion and subsequent light curve, we compare the NIR and optical nebular-phase data with a simple non-LTE nebular spectral model. We find that many of the spectral features are due to iron-group elements, and that the J-band deficit is due to a lack of emission lines from species that dominate the rest of the IR/optical spectrum. Nevertheless, some emission is unaccounted for, possibly due to inaccuracies in the cobalt atomic data. For some supernovae, blueshifts of 1000-3000 km s -1 are seen in infrared and optical features at 3 months. We suggest that this is due to clumping in the ejecta. The evolution of the cobalt/iron mass ratio indicates that 56Co-decay dominates the abundances of these elements. The absolute masses of iron-group elements which we derive support the basic thermonuclear explosion scenario for Type la supernovae. A core-collapse origin is less consistent with our data.
KW - Infrared: stars
KW - Stars: general
KW - Supernovae: general
UR - http://www.scopus.com/inward/record.url?scp=0001306946&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=0001306946&partnerID=8YFLogxK
M3 - Article
AN - SCOPUS:0001306946
VL - 290
SP - 663
EP - 679
JO - Monthly Notices of the Royal Astronomical Society
JF - Monthly Notices of the Royal Astronomical Society
SN - 0035-8711
IS - 4
ER -