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From Out of the Blue:

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Ben Shappee, Peter Brown, Michael Tucker, Chris Ashall, Tony Piro

Transients Down Under | 30 January 2024

Linking 2002es-like and 2003fg-like SNe Ia with Swift

Willem Hoogendam

AI Generated Image

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What Is a SN Ia?

Progenitor System

WD Mass

 

Explosion Mechanism

CO-WD accreting from

MS/RG companion

Detonates

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What Is a SN Ia?

Progenitor System

Single Degenerate

(WD + MS/RG)

WD Mass

Double Degenerate

(WD + WD)

Core Degenerate

(WD + AGB)

 

 

 

Explosion Mechanism

Deflagration to

Detonation Transition

Deflagration

(subsonic)

Detonation

(supersonic)

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Rising Light Curves

  • Rising light curve categories based on observation:
    • Single power-law rise
    • Double power-law rise
    • Non-monotonic bump

Hoogendam+2023

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Observational Influences on Rising Light Curves

Kasen 2010

Shock interaction may effect the rising light curve, with the effect strongest in the ultraviolet

  • Shocking non-degenerate companion

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Observational Influences on Rising Light Curves

Pakmor+2011

Shock interaction may effect the rising light curve, with the effect strongest in the ultraviolet

  • Shocking non-degenerate companion
  • Shocking material from a violent merger

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Observational Influences on Rising Light Curves

Joy Pollard

Shock interaction may effect the rising light curve, with the effect strongest in the ultraviolet

  • Shocking non-degenerate companion
  • Shocking material from a violent merger
  • Shocking pre-existing envelope or wind

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Swift Observations

Hoogendam+2023

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Model Predictions

Time from Explosion

Magnitude

Optical

Ultraviolet

Time from Explosion

C+O Envelope; Maeda+23

H-rich Wind; Moriya+23

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SNe Ia Subtypes:

  • Normal SNe Ia are very common

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SNe Ia Subtypes:

  • Normal SNe Ia (grey)
  • 1991T-like (red) and 1991bg-like (green) are also reasonably frequent and probably an extension of the normals (see Wolfgang Kerzendorf’s talk yesterday)

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SNe Ia Subtypes:

  • Normal SNe Ia (grey)
  • 1991T-like (red) and 1991bg-like (green)
  • Weird, peculiar, 2002es-like and 2003fg-like SNe Ia are more rare, and are certainly not extensions of the normal SNe Ia.

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Swift Observations

Blue: 2003fg-like

Orange: 2002es-like

Grey: Normal/Other

Hoogendam+2023

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Swift Observations

Hoogendam+2023

Brown: 2002es & 2003fg-likes

Grey: Normal/Other

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Linking the Extremes

  • 2002es-like and 2003fg-like SNe Ia both have
    • Unique UV colors and rising light-curve bumps
    • Weak or absent secondary maximum in r & i bands.
    • Low ejecta velocities
    • Nebular [O i] emission

Ashall+20 Diagram

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Carbon in 2002es-like and 2003fg-like SNe Ia

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Carbon in 2002es-like and 2003fg-like SNe Ia

SN 2019yvq

Burke+21

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Carbon in 03fg-like SNe

  • C envelope
    • Observational evidence suggests 2003fg-like SNe Ia explode inside a carbon circumstellar medium.
    • Some 2002es-like SNe Ia show C ii, suggesting a carbon circumstellar medium.
    • Because they have lower energies, 2002es-like SNe Ia may have C i.

Ashall+21

2003fg-like SNe Ia

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Conclusions

  • 2002es-like and 2003fg-like SNe Ia have unique UV colors and bumps.
  • These strange subtypes are more connected than initially thought.
  • We need more observations:
    • More rapid-follow-up observations of 2002es-like and 2003fg-like SNe Ia.
    • UV to NIR photometric and spectroscopic coverage.