Optical and near infrared observations of SN 1998bu

Spyromilio, J.; Gilmozzi, R.; Sollerman, J.; Leibundgut, B.; Fransson, Claes; Cuby, J. G.

doi:10.1051/0004-6361:20040570

Cited by 40 publications

(63 citation statements)

References 24 publications

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“…Especially the addition of the infrared has provided new insights (Spyromilio et al 2004, Sollerman et al 2004, Stritzinger & Sollerman 2007. SNe Ia have IR light curves, which after the peak phase are nearly flat for several hundred days until the IR catastrophe sets in and the ejecta cool enough so that the energy is radiated in fine-structure lines in the thermal infrared rather than in the optical or the near-infrared (Fransson et al 1996).…”

Section: Type Ia Supernovaementioning

confidence: 99%

Supernovae and cosmology

Leibundgut

2007

Gen Relativ Gravit

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The extreme luminosity and their fairly unique temporal behaviour have made supernovae a superb tool to measure distances in the universe. As complex astrophysical events they provide interesting insights into explosion physics, explosive nucleosynthesis, hydrodynamics of the explosion and radiation transport. They are an end product of stellar evolution and provide clues to the stellar composition. Since they can be observed at large distances they have become critical probes to further explore astrophysical effects, like dust properties in external galaxies and the star formation history of galaxies. Some of the astrophysics interferes with the cosmological applications of supernovae. The local velocity field, distorted by the gravitational attraction of the local large scale structure, and the reddening law appear at the moment the major limitations in the accuracy with which cosmological parameters can be determined. These absorption effects can introduce a secondary bias into the observations of the distant supernovae, which needs to be carefully evaluated. Supernovae have been used for the measurement of the Hubble constant, i.e. the current expansion rate of the universe, and the accelerated cosmic expansion directly inferred from the apparent faintness of the distant supernovae.

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Section: Type Ia Supernovaementioning

confidence: 99%

Supernovae and cosmology

Leibundgut

2007

Gen Relativ Gravit

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“…The spectrum of SN 1998bu, taken from Spyromilio et al (2004), was obtained at 398 days after explosion. This is one of the best S /N spectra available at this epoch, and one of the few covering the region above 8000 Å.…”

Section: Spectrummentioning

confidence: 99%

“…A problem is, however, that the spectrum is contaminated by a light echo (Cappellaro et al 2001), which especially in the blue gives a substantial contribution to the flux. We have removed this as discussed in Spyromilio et al (2004). For the reddening of SN 1998bu we adopt E B−V = 0.30 and a distance of 11 Mpc (Suntzeff et al 1999).…”

Section: Spectrummentioning

confidence: 99%

Three-dimensional modeling of type Ia supernovae – The power of late time spectra

Kozma¹,

Fransson²,

Hillebrandt

et al. 2005

A&A

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118

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Abstract. Late time synthetic spectra of type Ia supernovae, based on three-dimensional deflagration models, are presented. We mainly focus on one model, "c3_3d_256_10s", for which the hydrodynamics (Röpke 2005, A&A, 432, 969) and nucleosynthesis (Travaglio et al. 2004(Travaglio et al. , A&A, 425, 1029 was calculated up to the homologous phase of the explosion. Other models with different ignition conditions and different resolution are also briefly discussed. The synthetic spectra are compared to observed late time spectra. We find that while the model spectra after 300 to 500 days show a good agreement with the observed Fe II-III features, they also show too strong O I and C I lines compared to the observed late time spectra. The oxygen and carbon emission originates from the low-velocity unburned material in the central regions of these models. To get agreement between the models and observations we find that only a small mass of unburned material may be left in the center after the explosion. This may be a problem for pure deflagration models, although improved initial conditions, as well as higher resolution decrease the discrepancy. The relative intensity from the different ionization stages of iron is sensitive to the density of the emitting iron-rich material. We find that clumping, with the presence of low density regions, is needed to reproduce the observed iron emission, especially in the range between 4000 and 6000 Å. Both temperature and ionization depend sensitively on density, abundances and radioactive content. This work therefore illustrates the importance of including the inhomogeneous nature of realistic three-dimensional explosion models. We briefly discuss the implications of the spectral modeling for the nature of the explosion.

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“…In fact, very little has been published in this respect since the sparse, but pioneering, observations presented by Elias & Frogel (1983). Recently, two latetime H-band data points for SN 1998bu (250-350 days past maximum) suggest that this SN Ia also had a flat near-IR light curve at late phases (Spyromilio et al 2004). Our constant J-band and H-band light curves immediately highlight the main point of our study, the increasing importance of the near-IR at late phases.…”

Section: The Importance Of Near-ir Light Curvesmentioning

confidence: 99%

The late-time light curve of the type Ia supernova 2000cx

Sollerman

Lindahl

Kozma

et al. 2004

A&A

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117

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Abstract.We have conducted a systematic and comprehensive monitoring programme of the type Ia supernova 2000cx at late phases using the VLT and HST. The VLT observations cover phases 360 to 480 days past maximum brightness and include photometry in the BVRIJH bands, together with a single epoch in each of U and K s . While the optical bands decay by about 1.4 mag per 100 days, we find that the near-IR magnitudes stay virtually constant during the observed period. This means that the importance of the near-IR to the bolometric light curve increases with time. The finding is also in agreement with our detailed modeling of a type Ia supernova in the nebular phase. In these models, the increased importance of the near-IR is a temperature effect. We note that this complicates late-time studies where often only the V band is well monitored. In particular, it is not correct to assume that any optical band follows the bolometric light curve at these phases, and any conclusions based on such assumptions, e.g., regarding positron-escape, must be regarded as premature. A very simple model where all positrons are trapped can reasonably well account for the observations. The nickel mass deduced from the positron tail of this light curve is lower than found from the peak brightness, providing an estimate of the fraction of late-time emission that is outside of the observed wavelength range. Our detailed models show the signature of an infrared catastrophe at these epochs, which is not supported by the observations.

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Optical and near infrared observations of SN 1998bu

Cited by 40 publications

References 24 publications

Supernovae and cosmology

Supernovae and cosmology

Three-dimensional modeling of type Ia supernovae – The power of late time spectra

The late-time light curve of the type Ia supernova 2000cx

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