Документ взят из кэша поисковой машины. Адрес оригинального документа : http://www.atnf.csiro.au/research/LVmeeting/magsys_pres/gaensler_sn1987a.pdf Дата изменения: Sun Jul 29 09:57:43 2007 Дата индексирования: Sun Dec 23 12:40:16 2007 Кодировка: Поисковые слова: red supergiant

The Radio Supernova Remnant of SN 1987A at 20 Years of Age
Bryan Gaensler, Stephen Ng (USyd); Lister Staveley-Smith (UWA); Dick Manchester, Mike Kesteven, Lewis Ball, Tasso Tzioumis (ATNF)

© Anglo-Australian Observatory / David Malin Images


Circumstellar Structure
· Dense slow red supergiant wind, concentrated into equatorial plane · High-velocity low-density isotropic blue supergiant wind for final ~20 000 yr · Blue supergiant photoionises red supergiant wind (Chevalier & Dwarkadas 1996)

Hydro simulation (Michael et al. 2003)

HST WFPC2 (Pete Challis / SAINTS)

BSG wind

RSG wind


Prompt Phase
· · · · · Core collapse on 23 Feb 1987 Burst of radio emission seen by Power law decay; faded by day Synchrotron in BSG wind ( H , VLBI: V ~ 19000 ­ 30000 MOST on day 2; peaked on day 4 (Turtle et al. 1987) 150 r ­2) (Storey & Manchester 1987; Chevalier & Fransson 1987) km/s (Hanuschik & Dachs 1987; Jauncey et al. 1988)
843 MHz light curve (Ball et al. 1995)

© AAO / David Malin images


Birth of a Supernova Remnant
· MOST, & then ATCA, redetected radio emission in mid-1990 (day ~ 1200)

ATCA (ATNF/CSIRO)

MOST (Douglas Bock)

ATCA 9 GHz X-rays (soft) X-rays (hard)

· Steady increase in flux over 17 years · 9 GHz ATCA data ( source was extended 0.9) showed

(Staveley-Smith et al. 1992, 1993)

· Track size vs. time in u-v plane: first-order fit to thin spherical shell
(Staveley-Smith et al. 1993; Gaensler et al. 1997, 2007)
Staveley-Smith et al. (2007)


Expansion
· Shell was ~1.3 (0.3 pc) across at day ~1800 mean expansion ~ 38 000 km/s (1987-1992) · Since day 1800, approx. constant expansion at V = 4700 ± 100 km/s rapid deceleration slightly better fit: quadratic increase from 3600 km/s to 5200 km/s · Source now same size as optical ring · Radius & velocity match Chandra X-ray data (Park et al. 2004, 2006, 2007)

Gaensler et al. (2007)


Imaging & Super-Resolution

· Limb brightened · Bright lobes to east and west · Eastern lobe brighter than western lobe, & brightening faster

Gaensler et al. (2007)

ATCA 9 GHz diffraction limited (0.9 arcsec) super-resolved (0.5 arcsec)


Multi-Wavelength Comparison
· Two-lobed structures seen in radio, hard X-rays, optical · Lobes align with major axis of ring True morphology is likely a tilted ring · Brighter lobe is at larger radius Asymmetry in explosion/ejecta

ATCA / Chandra / HST (day 6300)

STIS Ly

(Michael et al. 1998)

Model

Prediction

Data (2006.9)

Michael et al. (2003)


Conclusions
· Turn-on & deceleration of radio source due to impact with dense RSG wind · Radio remnant of Supernova 1987A continues to steadily expand & brighten · Consistent multi-wavelength picture of reverse-shock region: - limb-brightened shell expanding at V ~ 5000 km/s - interaction is with stellar wind in equatorial plane - collision of ejecta piston with dense optical ring now upon us! · The Future: ALMA, ASKAP, SKA
NASA / ESA / G. Bacon

9 GHz images of SN 1987A, 1992 to 2007

SN 1993J (Bietenholz et al. 2003)

Cas A (L. Rudnick / T. Rector)