Clumps and Rings of Ejecta in SNR 0540–69.3 as Seen in 3D

• Published in: The Astrophysical journal Vol. 922; no. 2; pp. 265 - 279
• Main Authors: Larsson, J., Sollerman, J., Lyman, J. D., Spyromilio, J., Tenhu, L., Fransson, C., Lundqvist, P.
• Format: Journal Article
• Language: English
• Published: Philadelphia The American Astronomical Society 01-12-2021; IOP Publishing
• Subjects: Algorithms; Astrophysics; Balmer lines; Clumps; Companion stars; Core-collapse supernovae; Ejecta; Emission; Explosions; Hydrogen; Image reconstruction; Nebulae; Pulsar winds; Pulsars; Stellar winds; Supernova; Supernova dynamics; Supernova remnants; Very Large Telescope
• ISSN: 0004-637X; 1538-4357; 1538-4357
• DOI: 10.3847/1538-4357/ac2a41

Abstract
The distribution of ejecta in young supernova remnants offers a powerful observational probe of their explosions and progenitors. Here we present a 3D reconstruction of the ejecta in SNR 0540-69.3, which is an O-rich remnant with a pulsar wind nebula located in the LMC. We use observations from the Very Large Telescope (VLT)/MUSE to study H
β
, [O
iii
]
λ
λ
4959, 5007, H
α
, [S
ii
]
λ
λ
6717, 6731, [Ar
iii
]
λ
7136, and [S
iii
]
λ
9069. This is complemented by 2D spectra from VLT/X-shooter, which also cover [O
ii
]
λ
λ
3726, 3729, and [Fe
ii
]
λ
12567. We identify three main emission components: (i) clumpy rings in the inner nebula (≲1000 km s
−1
) with similar morphologies in all lines; (ii) faint extended [O
iii
] emission dominated by an irregular ring-like structure with radius ∼1600 km s
−1
and inclination ∼40°, but with maximal velocities reaching ∼3000 km s
−1
; and (iii) a blob of H
α
and H
β
located southeast of the pulsar at velocities ∼1500–3500 km s
−1
. We analyze the geometry using a clump-finding algorithm and use the clumps in the [O
iii
] ring to estimate an age of 1146 ± 116 yr. The observations favor an interpretation of the [O
iii
] ring as ejecta, while the origin of the H-blob is more uncertain. An alternative explanation is that it is the blown-off envelope of a binary companion. From the detection of Balmer lines in the innermost ejecta we confirm that SNR 0540 was a Type II supernova and that hydrogen was mixed down to low velocities in the explosion.