Delay time distribution sheds light on supernovae

[trinitree88]

Once a galaxy begins star formation, it marches onwards towards the eventual first supernovae. Considerations of star formation rates, and star formation histories alter the eventual supernovae rates. By examining the apparent supernovae rates, and their relative proportions of core collapse (CC-Sne) and single degenerate/double degenerate types (SD/DD) one can model different delay time distributions (DTD's) for the onset of supernovae and the resulting metallicities in their host galaxies. Certain models may be ruled out with increased observations (which is what we usually hope for). SEE:http://arxiv.org/PS_cache/arxiv/pdf/...006.3576v1.pdf

and in a related paper, using both new and archived data from HST and the Advanced Camera for Surveys, the authors, Keren Sharon et al, find that the supernovae rate appears to be non-evolving as far as 0.5 < z < 0.9 ( a pretty heady group )

SEE:http://arxiv.org/PS_cache/arxiv/pdf/...006.3757v1.pdf

[Nereid]

There's a pretty big literature on this topic, and it's a very active area of research. It will be interesting to read the papers which cite the Sharon et al. one.

For some related reading, and to get a handle on the challenges involved in coming up with robust estimates of DTD's, check out Supernovae in Low-Redshift Galaxy Clusters: Observations by the Wise Observatory Optical Transient Search (WOOTS),
Evidence for short-lived SN Ia progenitors,
Supernova rates from the Southern inTermediate Redshift ESO Supernova Search (STRESS),
The Ages of Type Ia Supernova Progenitors,
The Extended HST Supernova Survey: The Rate of SNe Ia at z>1.4 Remains Low,
An Intensive HST Survey for z>1 Supernovae by Targeting Galaxy Clusters,
Type Ia Supernovae Rates and Galaxy Clustering from the CFHT Supernova Legacy Survey,
A Measurement of the Rate of Type Ia Supernovae in Galaxy Clusters from the SDSS-II Supernova Survey,
The radial distribution of type Ia supernovae in early-type galaxies: implications for progenitor scenarios,
The Palomar Transient Factory: System Overview, Performance and First Results,
The supernova rate in local galaxy clusters,
The supernova rate and delay time distribution in the Magellanic Clouds,
Nearby Supernova Rates from the Lick Observatory Supernova Search. IV. A Recovery Method for the Delay Time Distribution, and
Delay Time Distribution Measurement of Type Ia Supernovae by the Subaru/XMM-Newton Deep Survey and Implications for the Progenitor.

[Roger E. Moore]

My impression is that the double-degenerate model is better supported than the single-degenerate one, but the latter cannot be ruled out. This sound right?

[Jerry]

Nice set of reference, thanks Neried!

http://arxiv.org/abs/0803.1130v1

Poznanski et al. (2007) have found roughly half the Type Ia supernovae near z ∼ 1 as was seen in the GOODS, and essentially none at lower-z. Given the single search epoch and acute solid angle surveyed, it is not unlikely for the SDF survey to have a null result at lower redshifts. However, the differences near z ∼ 0.8 seem appreciable. It serves as another example of a growing problem; the relatively large discrepancies in rate measurements by several authors in this redshift range (see Figure 1). It is disappointing that there does not as yet appear to be a resolution in these measured discrepancies, as there could be great power in combining rate results to gain further insight on the modality of the SN Ia delay-time distributions, and ultimately the progenitors mechanisms of Type Ia supernovae. But until then, this analysis will remain necessarily limited. ,,

Here we have discussed possible solutions to this discrepancy and found:

• It is unlikely that the difference between model predicted rates and observed rates is
due to statistical fluctuations or cosmic variance.
• It is also unlikely that the low rate we measure is due to an underestimate of the host
galaxy dust extinction or an overestimate detection efficiency.
• A bimodal model with a larger fraction of delayed Type Ia and that takes into account
SFR hidden by dust results in a better fit to data.
• Another possible scenario that would result in a decrease in the high redshift SNR is
if the WD explosion efficiency deceases at high redshift.

Only four possibilities? Finding far fewer events than expected based upon the local sample is inconsistent with other observables, such as the spectral energy distribution. How much weight should this have?

Once again, I think they are systemically underestimating the luminosity of the most distant events and in doing so, missing badly on either the distance modules, the obscuration rates, or both.

[Nereid]

Nearby Supernova Rates from the Lick Observatory Supernova Search. I. The Methods and Database (link is to arXiv abstract).