Point-symmetric morphology in supernova remnant G11.2-0.3: the jittering jets explosion mechanism

TL;DR

The study investigates whether jittering jets (JJEM) or the delayed neutrino mechanism is the primary driver of core-collapse supernovae by examining remnant morphology. Using high-resolution X-ray and radio images of SNR G11.2-0.3, it identifies three opposite jet-pair structures—two circum-jet rings (Pair 1), a bright inner SE–NW strip (Pair 2), and an ear-nozzle pair (Pair 3)—all interpreted as jet activity during the explosion. Pair 3 is proposed as the final, more energetic episode, with accretion aligning the neutron star spin axis with the jet axis, matching the current pulsar jets. The jets are inferred to have been active for a short time ($\lesssim 1$ s), and additional weaker jet pairs may have participated. Collectively, these point-symmetric features strengthen the JJEM as the primary CCSN mechanism and demonstrate how remnant morphologies can serve as decisive diagnostics between explosion models.

Abstract

I identify a point-symmetric morphology in the core-collapse supernova (CCSN) remnant SNR G11.2-0.3 composed of three pairs of opposite morphological features, and attribute their shaping to three energetic pairs of jets during the explosion process in the frame of the jittering jets explosion mechanism (JJEM). The pairs of morphological features are two opposite rings, a strip of dense ejecta extending on both sides of the central pulsar PSR J1811-1925, and an ear-nozzle opposite structure. According to the JJEM, additional weaker pairs of jets may also have participated in the explosion. The jets' axis from the ear to the nozzle coincides with the axis of the presently active pulsar jets, which is the pulsar spin axis. The jets of this pair were the last that the newly born neutron star launched during the explosion, and the accretion disk that launched these jets spun up the neutron star in the same direction as the jets. The identification of a point-symmetric morphology in SNR G11.2-0.3 strengthens the claim that the JJEM is the primary explosion mechanism of CCSNe.

Figures (4)

• Figure 1: A figure adapted from Robertsetal2003, comparing X-ray pulsar wind nebula (PWN) emission and radio emission. Red: $0.6-1.65 ~\rm{keV}$ X-ray. Green: 3.5 cm radio. Blue: $4-9 ~\rm{keV}$ X-ray. All are at $5^{\prime \prime}$ resolution. I added the identification of two rings and the directions of the two jets that I suggest shaped these circum-jet rings during the explosion. The two images are identical, allowing a clear view without marks in the upper panel. The two rings define Jet Pair 1. Right ascension (J2000) ticks are 18:11:40, 18:11:30 and 18:11:20, and declination (J2000) ticks are $-19:27:00$, $-19:25:00$, and $-19:23:00$.
• Figure 2: A Chandra image adapted from ZhengJTetal2023RAA; the two circles with their labels and the red arrow are their marking and irrelevant to this study. There is a bright inner strip extending from southeast to northwest. I suggest a shaping by a pair of jets, Pair 2. I mark the general directions of the two jets with the orange biconical, which represents the uncertainty in their directions rather than their shapes.
• Figure 3: Two images of SNR G11.2-0.3, with the three pairs of jets identified in this study. The ellipses and arrows of Pair 1 are as in Figure \ref{['Fig:G11FigureOuter1']} (and on the same relative scale), and the biconical shape is as in Figure \ref{['Fig:G11Inner2']}. The double-sided arrow defines Pair 3, two opposite jets that shaped the ear-nozzle structure during the explosion; its length has no meaning, as it only marks the jets' axis. The direction is as the present pulsar jets, but the jets of Pair 3 were active for only a second or so during the explosion. (a) An image of SNR G11.2-0.3 adapted from the https://chandra.harvard.edu/photo/2007/g11/. Color code is for energy bands: red $0.5-1.5 ~\rm{keV}$; green $1.5-2.5 ~\rm{keV}$; blue $2.5-8 ~\rm{keV}$. (Credit: NASA/CXC/Eureka Scientific/Robertsetal2003) (b) Another image of SNR G11.2-0.3 from https://chandra.harvard.edu/photo/2001/1227/. Color code is for energy bands: red $0.6-1.65 ~\rm{keV}$; green $1.65-2.25 ~\rm{keV}$; blue $2.25-7.5 ~\rm{keV}$. The intensity color codes of the two panels differ, and so do the scales; in panel (b), the SNR is $1.08$ as large as in panel (a). (Credit: NASA/McGill/Kaspietal2001)
• Figure 4: Two images of SNR G11.2-0.3 adapted from ZhangYetal2025. I added a double-sided arrow through the pulsar at the center and the marks of the nozzle and ear. The double-sided arrow length is $4.4^{\prime}$, as in Figure \ref{['Fig:G11Inner1']}. (a) Australia Telescope Compact Array (ATCA) $3 ~\rm{cm}$ radio image. (b) RGB image: green: 6 cm ATCA radio map; red: $2.7-9.0 ~\rm{keV}$ (Chandra); Blue: $0.5-2.0 ~\rm{keV}$ (Chandra).