UV Observations:
Past, Current, Future@fox_ori
Ori FoxSTScISouthern Ring Nebula,
JWST/NIRCam

02/24/2023

UV Observations:
Past, Current, Future@fox_ori
Ori FoxSTScISouthern Ring Nebula,
JWST/NIRCam

02/24/2023

Fox+11, Szalai+18,21

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IIn
Ia-CSM
IIP-n
Ibn
FBOT
Icn
SNCC2i0.9

Tinyanont+21

Can’t Find Citation? Help?

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Fox & Smith 2019

Similar Phase Space
Similar Light Curves
Similar Spectra Progenitor systems
 Late stages of massive star evolution
 Stellar feedback Dust production

 Shock breakout
 Metallicity and CNO Processing
 Confirming Shock Interaction

 Bolometric Luminosity Densities and Mass-Loss History

Observations: Roming (2012), Ofek (2010), Botticella (2010)
Pritchard (2014), PhD Thesis: ``Ultraviolet observations ofCCSNe”
 Theory: Falk (1978), Chevalier & Fransson (1994)
Chevalier & Fransson 94

Shock Velocity (cm/s)
Margalit+22

Thompson Optical DepthCSM Interaction

FBOTs
Margalit+22
Margalit+22

Multitude of resonance lines of ions with different ionization potentials. Ideallysuited for inferring the CSM velocity and density structure. N V 1239-1243, Si IV
1394-1403, C IV 1548-1551, and Mg II 2800.

Type IIn SN 1995N
HST/FOSChevalier+94, Fransson+02, Boian+19

Fransson+05

Lines be explained as a result of photoionization byX-rays and UV The low-density, unshocked ejecta emits mostly
high-ionization at C iii–iv, N iii–v, and O iii–vi.
 The high density, reverse shock emits mostly neutralor singly ionized ions, such as H i lines, Mg ii, andFe ii.
Fransson+05

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Fransson+05Lines be explained as a result of photoionization by
X-rays and UVThe low-density, unshocked ejecta emits mostly
high-ionization at C iii–iv, N iii–v, and O iii–vi.
The high density, reverse shock emits mostly neutralor singly ionized ions, such as H i lines, Mg ii, andFe ii.
Boxlike lines from thin, spherical shell in 93JLine profiles of 98S less clear (ring like 87A?)
No clear distinction in line shapes from different
regions
Optical spectra show that relatively little hydrogen ispresent between the reverse shock and the oxygenrich core.

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

Fransson+05

Lines be explained as a result of photoionization byX-rays and UVThe low-density, unshocked ejecta emits mostly
high-ionization at C iii–iv, N iii–v, and O iii–vi.
The high density, reverse shock emits mostly neutralor singly ionized ions, such as H i lines, Mg ii, andFe ii.
Boxlike lines from thin, spherical shell in 93JLine profiles of 98S less clear (ring like 87A?)
No clear distinction in line shapes from different
regions
Optical spectra show that relatively little hydrogen ispresent between the reverse shock and the oxygenrich core.
Significant nitrogen enrichment in the supernova
ejecta and in the circumstellar gas.

Fransson+05

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In all cases where CNO abundances have been measured, the N/C ratio is considerablylarger than the solar value, N=C 1⁄4 0:25.
The interpretation is that all of these progenitors are believed to have undergone
extensive mass loss prior to the explosion.
Enrichment due to or even directly implies mass loss? Could also be rotational mixing or
binary mass-exchange?
Doing this for SN 1987A, for example, is difficult: need to reconcile BSG progenitor, redto-blue supergiant ratio in LMC, and CNO ratios for consistent model. This is one of thestrong factors leading to the merger model.
Numbers also consistent with Eta Car (Smith & Morse 04, Fransson+14).

Fox+20Total radiated energy in excess of 1050 erg
Pre-explosion mass loss rate of 10-2 M_sol/yr
Total mass loss >1 M_sol

Type IIn SN 2005ip
HST/STIS

Compared to Solar the above ratios areenhanced by factors of 38-51 for N/C and>8.714 for N/O, consistent with products fromCNO burning. But can’t differentiate between
a 20 and 100 M_sol star.
Fox+11, Szalai+18

Fox+20Type IIn SN 2010jl Day 44
HST/COS R~12,000

Keenan+94, Fransson+14

Ratios showed as a function of temperature and density. Overplotted
are the observed ranges of these ratios as horizontal lines.
 Densities consistent with 3x106 – 108 cm-3
Dessart+22

Interaction model based onhelium-star explosion.

Run CMFGEN in standard, steadystate, line blanketing modeRadiation-hydrodynamics andradiative-transfer calculations

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Assume model compressed into adense shell.

Wang+23 (In Prep)Impact of He content and ejecta mass on SED



The model with higher mass and lower He content shows weak/no He I lines
and exhibits extra blanketing in the UV (mostly because of the greater mass but
identical power) a dense shell.

Dessart+22Percentage of optical flux between 4000-8000 ang that is emitted in He I 5875
Ang for different CDS configurations of the helium star models.

Dense Wine

Ejected Shell
Dessart+22

Margalit+22
Margalit+22

Maeda+22

Qinan Wang(JHU) Grad StudentWang+23 (in prep)
Wang+23 (in prep)Qinan Wang(JHU) Grad Student

Wang+23 (in prep)
Wang+23 (in prep)Anika Goel
Kansa StateSTScI Summer Student

Jdaviz: JWST Data Analysis Visualization Tools

Wang+23 (in prep)
Wang+23 (in prep)Qinan Wang(JHU) Grad Student

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Relatively standard Mg lines
High ionization C IV and N V

Wang+23 (in prep)Qinan Wang
(JHU) Grad Student

Wang+23 (in prep)Comparison of interaction models and spectra
for 20nxt at 11, 20, 34, and 36 days postmaximum. The top two panels include UVspectra, as well.

Best fit a moderate mass (4 M_sol) He-starmodel initially on the He ZAMS, corresponding
to a pre-SN star mass of 3.16 M_sol.

In other words, we effectively exclude highmass stars and point towards lower-mass stars
that, in addition, have evolved an interacting
binary and lost their H-rich envelop throughmass transfer.

Possible mechanisms: nuclear flashes, repeatedmass transfer in short-period binaries, double
WD merger, Thorne-Zytkow-like object collapse
to NS or BH, or…???

Question: Can you differentiate from a Hewhite dwarf?

Qinan Wang(JHU) Grad Student

Host galaxy median star formation rate density among SN Ibn

Wang+23 (in prep)

Perley+22

Many similarities, but many differences:

21csp has a number of additional carbon lines, but missing strong doublet NV 1238/1242.
High velocity absorption component not seen in the 2020nxt (possibly contamination)

And what about FBOTs? Need spectraQinan Wang(JHU) Grad StudentMany similarities, butmany differences:

Wang+23 (in prep)

Strong high-ionization lines
Missing MgOther?

Graham+19

 91T like SN at z=0.038
 NUV point source on day 686
 CSM inner radius ~5x1016 cm

Dessart+22

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UV is critical fordifferentiating IIP (andother) shell models

IIPs, even non-interacting
ones, should exhibit latetime UV emission

Melissa Shahbandeh
STScI Postdoc

Shahbandeh+23

Keck spectra show clear signatures of CSM interaction even 6500 days postexplosion. No accompanying UV observations yet.

Melissa Shahbandeh
STScI Postdoc

SN 2004etSN 2017eaw

Shahbandeh+23

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Huge dust masses illuminated by radiative emission from shock interaction(more next week)

Vasylyev+22: Compares early time UV spectra of SNe IIP (21yja,99em,05cs, 05ay,12aw) finding diversity. UV spectrum of 21yja is dominated by Fe II and Fe III,
causing line blanketing. Variations due to combination of metallicity, reddening,and pre-explosion behavior.

Ben-Ami+15: STIS UV spectra of SNe IIb 2013df and compared to 93J, 01ig, 11dh,
and 13df). IIb’s can be divided into two groups: 93J, 11dh, and 13df -> UVcontinuum flux excess not affected by line absorption…implying it originates above
the photosphere. Correlation between shock-cooling phase duration and amountof flux in the UV attributed to shocked CSM.

 Multi-wavelength, particularly in the UV
 Rapid response, to get data pre-peak to probe

pre-shocked CSM
 Sensitivity to observe at late-time, nebularphase Observations: Statistically significant data sets of all new types of SNe Dedicated UV spectrograph in space (i.e., UVEX) FBOTs, SNe Icn, SNe Ia-CSMs
 Theory: Non-LTE and the consistent calculation of the full spectrum
 FBOTs, SNe Icn, SNe Ia-CSMs
 Pushing to multi-dimensions
 Many people are working on this but it seems generally

limited to analytical or semi-analytical studies, with lots ofapproximation, no radiative transfer, sometimes no dynamicsetc.

 SNe IIn: Have high CNO ratios -> lower mass

binaries?
 SNe Ibn: Dessart models require low mass stripped
helium star, suggestive of possible low masscompanion SNe Icn/FBOTs/Ia-CSM: Modeling required, but it’s
fun to hypothesize that similarities suggest there
could be a trend.
 SNe IIPn: Advantage to getting on them early tomeasure UV excess, but late-time observations will
prove quite pivotal in coming years Could SNe be the only SNe from single massivestars???

 CSMs around supernovae are:
 Big
 Big News Extreme Multi-wavelength observations, specifically inthe UV, are necessary to constrain theenergetics, mass-loss history, and explosion.
 In the future, a focus on UV observations andtheory will drive this field forwardOptical spectra are dominated by CSM interaction at all epochs
You never really observe the underlying ejecta
Characteristics of the surrounding CSM are overshadowed by the shockphysics itself, leaving relatively little to gleam from optical spectra
Type IIn SN 2005ip

Fox+20

Optical spectra are dominated by CSM interaction at all epochs
You never really observe the underlying ejecta
Characteristics of the surrounding CSM are overshadowed by the shockphysics itself, leaving relatively little to gleam from optical spectra
Type IIn SN 2005ip

Fox+20Fox+19

 Similarities between some FBOTs* and SNe Ibn
 *FBOT definition required: 18cow-like vs fast evolving.
See Perley+21, Ho+20, Coppejans+20

Fox+19, See also: Margutti+19

*Mg II is a low-ionization line that should be in
all SNe with CSM interaction, yet it’spractically absent in SNe Icn and Ia-CSM.
*Is this due to the degree of shock
interaction? Or does it indicate something
more about the degree of CNO processing?