# Presentation: 709493

## Supernovae and Gamma Ray Bursts, Aspen Colorado, 20/2/07

**Joe Anderson**
**Astrophysics Research Institute,**
**Liverpool John Moores University**

***Supernovae and Gamma Ray Bursts, Aspen Colorado, 20/2/07***

## Constraints on supernova progenitors from parent stellar populations

_**Constraints on supernova progenitors from parent stellar populations**_
** ****PhD Project at the ARI, Liverpool John Moores University**
** ****Collaborators: **
**- Phil James, Maurizio Salaris & Sue Percival**
** ****Constraining the nature of all types of SN progenitors through **
**  ****spatial correlations of positions of historical SNe with different**
**  ****stellar populations**

_**SN1998dh (Ia),**_
_**NGC 7541**_

## Supernovae and recent star formation

_**Supernovae and recent star formation**_
_**H**__**α**__** Galaxy Survey (H**__**α**__**GS)**_
_**(James et al. 2004)**_
-  **H****α**** and *****R-*****band imaging of 334 local spiral and irregular**
**  ****galaxies**
** ****H****α**** gives quantitative measure of star formation rate via**
**  ****ionising flux of young hot stars**

_**Supernovae**_
-  **‘****Only stars with masses > 10 solar mass and lifetimes of < 20**
**  ****Myr contribute significantly to the H****α**** ionising flux’**
**	****	****- Kennicutt (1998)**
** ****This should be the same stellar population that gives rise to**
**  ****core-collapse SNe**

***Supernovae and Gamma Ray Bursts, Aspen Colorado, 20/2/07***

## Supernovae and recent star formation

** ****63 historical SNe found within H****α****GS sample**
** ****SNe numbers supplemented with further H****α**** imaging**
**	****- on-going Liverpool Telescope (LT) allocation**
**	****- Isaac Newton Telescope (INT) exposures**
** ****Current sample:**
**- 51 SNII, 20 SNIb/c, 15 SNIa and 15 unclassified **

_**Initial questions to ask:**_
-  **Do SNII and SNIb/c trace the same high mass stellar**
**  ****population?**
** ****Do the positions of SNIa show any association with a**
**  ****young stellar population, as traced by H****α**** emission?**

***Supernovae and Gamma Ray Bursts, Aspen Colorado, 20/2/07***

## SN2004A (II), NGC 6207

_**SN2004A (II), NGC 6207**_

## 1987K (II), NGC 4651

_**1987K (II), NGC 4651**_

## SN1997dt (Ia), NGC 7448

_**SN1997dt (Ia), NGC 7448**_

## Normalised Cumulative Rank Pixel Function

_**Normalised Cumulative Rank Pixel Function**_
_**(NCR)**_
_**(James & Anderson 2006, A & A, 453, 57-65)**_

-  **Pixels on H****α**** host galaxy images sorted into increasing **
**  ****pixel count**
** ****Cumulative distribution of pixel counts formed**
** ****Each pixel on image has an NCR value between 0 and 1:  ****	****	**** - NCR = 0 → zero H****α**** flux/sky values**
** ****- NCR = 1 → centre of brightest HII region**
**   ****within host galaxy**
** ****If a SN progenitor type accurately traces the SF of the host**
**  ****galaxy, then one would expect a mean NCR value for that**
**  ****progenitor of 0.5 and a flat distribution**

***Supernovae and Gamma Ray Bursts, Aspen Colorado, 20/2/07***

## Results & Conclusions

_**SNII**_
-  **Mean NCR value = 0.212 (standard error on mean = 0.035)**
**	****	****- 67% of SNII population falling on HII regions**
** ****1/3 of the SNII progenitor population showing no apparent**
**  ****association with SF regions as traced by H****α**** emission**
** ‘****Runaway’ population**
**	****- possible peculiar velocities calculated**
**	****- population may be OB runaway stars ****	****	****  that have moved position between birth ****	****	****  and explosion**

***Supernovae and Gamma Ray Bursts, Aspen Colorado, 20/2/07***

-  **Embedded in dust?**

_**SN2004A (II), NGC 6207**_

## SNIb/c

_**SNIb/c**_
** ****Mean NCR value = 0.536 (0.054)**
**	****	****- SNIb = 0.379 (0.097)**
**	****	****- SNIc = 0.588 (0.113)**
** ****Progenitor population seems to accurately trace high mass SF**
** ****Some suggestion SNIc population may be more concentrated**
**  ****towards centre of HII regions**

_**SN1991N (Ic),**_
_**NGC 3310**_

_**SN1983I (Ib), NGC 4051**_

## SNIa

_**SNIa**_
** ****Mean NCR value = 0.247 (0.083)**
** ****	****	****- 46% of population falling on HII regions**
-  **Almost 1⁄2 of the progenitors show signs of an association**
**  ****with a young stellar population**
** ****This fraction may form the ‘prompt’ population recently**
**  ****suggested by Mannucci et al. (2006)**
** **
** ‘****Prompt’ progenitors may have**
**  ****lifetimes longer than that of H****α**
**  ****emission**
** ****Multi-wavelength study needed**
**  ****to further constrain SNIa **
**  ****progenitors**

## Future work

_**Future work**_
_**SNIa progenitors**_
** ****Near-IR observations:**
**- *****J*****- and *****K*****- band imaging**
**- trace old stellar mass**
** ****Optical imaging:**
** ****	****	****- additional H****α**** imaging**
**- optical broad band *****B*****-, *****V*****- and *****R- *****imaging**
** ****Use observations in conjunction with BaSTI stellar **
**  ****population synthesis models of Salaris and collaborators**
**  ****(e.g. Pietrinferni et al. 2004)**
** ****Use of models and observations to trace a wide range in**
**  ****stellar ages and metallicities**

## Summary

_**Summary**_
** ‘****Runaway’ SNII, a large fraction of SNII do not seem to be**
**  ****associated with a young stellar population as traced by H****α**
**  ****line emission**
** ****SNIb/c accurately trace high mass star formation**
** ****Possible link between SNIa and a young stellar environment**
** ****Other results not included here, see James & Anderson (2006)**
**- radial positions of SNe within host galaxies**

** ****More detailed study of SNIa progenitor environments**
** ****Application of technique to SNII and SNIb/c**

## Supernovae and Gamma Ray Bursts, Aspen Colorado, 20/2/07

***Supernovae and Gamma Ray Bursts, Aspen Colorado, 20/2/07***

## Other Results

_**Other Results**_
_**(James & Anderson 2006)**_
** ****Investigation into radial positions of SNe within host galaxies**
**- central deficit of all SN types **
**- suggestion that SNIb/c may be more centrally**
**  ****concentrated than SNII: metallicity effect?**

## Supernovae and Gamma Ray Bursts, Aspen Colorado, 20/2/07

***Supernovae and Gamma Ray Bursts, Aspen Colorado, 20/2/07***

- James et al. 2006

## Supernovae and Gamma Ray Bursts, Aspen Colorado, 20/2/07

## Supernovae and Gamma Ray Bursts, Aspen Colorado, 20/2/07