1. New Radio Observations of
Supernova 1978K
Stuart Ryder
International Telescopes Support Office
Australian Astronomical Observatory

2. NGC 1313 SN 1978K Image credit: T.A. Rector/University of Alaska
Anchorage, T. Abbott and NOAO/AURA/NSF

3. My favourite supernova
Supernova 1978K in NGC 1313 (4.6 Mpc).
Nearest “middle age” supernova after SN 1987A.
Only discovered in 1991 from ATCA radio, ROSAT X-ray, unusual 2.3m optical spectrum.
Type IIn = narrow emission lines on broad base  dense circumstellar medium.
Luminous Blue Variable progenitor?
Extremely radio luminous.

4. Radio properties of SNe
Romero-Cañizales et al. 2014

5. ATCA radio spectrum 2014
SN 94 GHz ~300× brighter than SN 1987A.
Turnover at low freq. due to free-free absorption by intervening H II region / circumstellar nebula.

6. Next stop: ALMA
Awarded 4.6h (Priority B) in Cycle 3 for Bands 3, 4, 6, 7 (90–340 GHz).
Characterise SED – upturn from cold dust emission?

7. Watching a supernova expand
SN 1987A with ATCA

8. Australian Long Baseline Array
ASKAP
ATCA
Mopra
Ceduna
Parkes
Hobart

9. SN 1978K VLBI March 2015
Free expansion at 10,000 km s-1 for 37 years  0".04
LBA 8.4 GHz = 0".003
SN remnant diameter < 0.005" (0.11 pc)
Past average expansion velocity < 1,500 km s-1

10. Deceleration of SN 1978K
For R ~ t0.78, current expansion velocity ~ 1,000 km s-1
(cf. 1,600 – 6,300 km s-1 in SN 1987A)
Kuncarayakti et al (2016) optical spectroscopy  Ṁ ~ 0.01 M yr MCSM ~ 1 M

11. Recap Not all core-collapse supernovae are like SN 1987A!
ATCA’s 1–100 GHz coverage → measure SN 1978K’s cold dust mass with ALMA.
SN 1978K has been significantly decelerated by its dense circumstellar medium, and has slowed to ~1,000 km s-1 after 37 years.

12. Job opportunity
Joint Macquarie University / International Telescopes Support Office Lecturer in Astronomy.
3 year fixed-term.
Applications close 14 August 2016.
See July 2016 AAS Job Register (
Applications from female and minority candidates are strongly encouraged.
Questions? Contact me or Mark Wardle.