Nathan Smith
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View article: Optimizing Kilonova Searches: A Case Study of the Type IIb SN 2025ulz in the Localization Volume of the Low-significance Gravitational Wave Event S250818k
Optimizing Kilonova Searches: A Case Study of the Type IIb SN 2025ulz in the Localization Volume of the Low-significance Gravitational Wave Event S250818k Open
Kilonovae, the ultraviolet/optical/infrared counterparts to binary neutron star mergers, are an exceptionally rare class of transients. Optical follow-up campaigns are plagued by contaminating transients, which may mimic kilonovae but do n…
View article: Mid-infrared Dust Evolution and Late-time Circumstellar Medium Interaction in SN 2017eaw
Mid-infrared Dust Evolution and Late-time Circumstellar Medium Interaction in SN 2017eaw Open
We present JWST/Mid-Infrared Instrument (MIRI) and complementary ground-based near-infrared observations of the Type II SN 2017eaw taken 6 yr postexplosion. SN 2017eaw is still detected out to 25 μ m and there is minimal evolution in the m…
View article: JWST Observations of SN 2023ixf. II. The Panchromatic Evolution between 250 and 720 Days after the Explosion
JWST Observations of SN 2023ixf. II. The Panchromatic Evolution between 250 and 720 Days after the Explosion Open
We present the nebular phase spectroscopic and photometric observations of the nearby hydrogen-rich core-collapse supernova (CCSN) SN 2023ixf, obtained through our JWST programs. These observations, combined with ground-based optical and n…
View article: Hubble Space Telescope Deep Upper Limits Rule out a Surviving Massive Binary Companion to the Type Ic Supernova 2012fh
Hubble Space Telescope Deep Upper Limits Rule out a Surviving Massive Binary Companion to the Type Ic Supernova 2012fh Open
Current explanations of the mass-loss mechanism for stripped-envelope supernovae (SNe) remain divided between single and binary progenitor systems. Here we obtain deep ultraviolet (UV) imaging with the Hubble Space Telescope (HST) of the T…
View article: Two Decades of Dust Evolution in SN 2005af through JWST, Spitzer, and Chemical Modeling
Two Decades of Dust Evolution in SN 2005af through JWST, Spitzer, and Chemical Modeling Open
The evolution of dust in core-collapse supernovae (SNe), in general, is poorly constrained owing to a lack of infrared observations a few years after explosion. Most theories of dust formation in SNe heavily rely only on SN 1987A. In the l…
View article: Acute dislocations of the sternoclavicular joint: treatment and outcomes
Acute dislocations of the sternoclavicular joint: treatment and outcomes Open
Objectives: Identify treatment and describe outcomes and complications of acute anterior and posterior sternoclavicular joint dislocation. Design: Retrospective case series. Setting: Twelve level-one trauma centers. Patient/Participants: O…
View article: SN 2019tsf: Evidence for Extended Hydrogen-poor CSM in the Three-peaked Light Curve of Stripped Envelope of a Type Ib Supernova
SN 2019tsf: Evidence for Extended Hydrogen-poor CSM in the Three-peaked Light Curve of Stripped Envelope of a Type Ib Supernova Open
We present multiband ATLAS and ZTF photometry for SN 2019tsf, a Type Ib stripped-envelope supernova (SESN). The slow spectral evolution could be associated with an uncommon explosion mechanism specific to this SN. Possible explanations inc…
View article: Very Late-time JWST and Keck Spectra of the Oxygen-rich Supernova 1995N
Very Late-time JWST and Keck Spectra of the Oxygen-rich Supernova 1995N Open
We present new JWST/MIRI Medium Resolution Spectroscopy and Keck spectra of SN 1995N obtained in 2022–2023, more than 10,000 days after the supernova (SN) explosion. These spectra are among the latest direct detections of a core-collapse S…
View article: One Year of SN 2023ixf: Breaking through the Degenerate Parameter Space in Light-curve Models with Pulsating Progenitors
One Year of SN 2023ixf: Breaking through the Degenerate Parameter Space in Light-curve Models with Pulsating Progenitors Open
We present and analyze the extensive optical broadband photometry of the Type II SN 2023ixf up to 1 yr after explosion. We find that, when compared to two preexisting model grids, the bolometric light curve is consistent with drastically d…
View article: HST Deep Upper Limits Rule Out a Surviving Massive Binary Companion to the Type Ic Supernova 2012fh
HST Deep Upper Limits Rule Out a Surviving Massive Binary Companion to the Type Ic Supernova 2012fh Open
Current explanations of the mass-loss mechanism for stripped-envelope supernovae remain divided between single and binary progenitor systems. Here we obtain deep ultraviolet (UV) imaging with the Hubble Space Telescope (HST) of the Type Ic…
View article: JWST/MIRI Observations of Newly Formed Dust in the Cold, Dense Shell of the Type IIn SN 2005ip
JWST/MIRI Observations of Newly Formed Dust in the Cold, Dense Shell of the Type IIn SN 2005ip Open
Dust from core-collapse supernovae (CCSNe), specifically Type IIP supernovae (SNe IIP), has been suggested to be a significant source of the dust observed in high-redshift galaxies. CCSNe eject large amounts of newly formed heavy elements,…
View article: SN 2021hpr: A Normal Type Ia Supernova Showing Excess Emission in the Early Rising Phase
SN 2021hpr: A Normal Type Ia Supernova Showing Excess Emission in the Early Rising Phase Open
We present extensive optical observations of a nearby Type Ia supernova (SN Ia), SN 2021hpr, located in the spiral galaxy NGC 3147 at a distance of ∼45 Mpc. Our observations cover a phase within ∼1–2 days to ∼290 days after the explosion. …
View article: JWST and Ground-based Observations of the Type Iax Supernovae SN 2024pxl and SN 2024vjm: Evidence for Weak Deflagration Explosions
JWST and Ground-based Observations of the Type Iax Supernovae SN 2024pxl and SN 2024vjm: Evidence for Weak Deflagration Explosions Open
We present panchromatic optical $+$ near-infrared (NIR) $+$ mid-infrared (MIR) observations of the intermediate-luminosity Type Iax supernova (SN Iax) 2024pxl and the extremely low-luminosity SN Iax 2024vjm. JWST observations provide unpre…
View article: Photometry and Spectroscopy of SN 2024pxl: A Luminosity Link Among Type Iax Supernovae
Photometry and Spectroscopy of SN 2024pxl: A Luminosity Link Among Type Iax Supernovae Open
We present extensive ultraviolet to optical photometric and optical to near-infrared (NIR) spectroscopic follow-up observations of the nearby intermediate-luminosity ($M_V = -$16.81$\pm$0.19~mag) Type Iax supernova (SN) 2024pxl in NGC 6384…
View article: Very Late-Time JWST and Keck Spectra of the Oxygen-Rich Supernova 1995N
Very Late-Time JWST and Keck Spectra of the Oxygen-Rich Supernova 1995N Open
We present new {\it JWST}/MIRI MRS and Keck spectra of SN 1995N obtained in 2022--2023, more than 10,000 days after the supernova (SN) explosion. These spectra are among the latest direct detections of a core-collapse SN, both through emis…
View article: The Immediate, Exemplary, and Fleeting Echelle Spectroscopy of SN 2023ixf: Monitoring Acceleration of Slow Progenitor Circumstellar Material Driven by Shock Interaction
The Immediate, Exemplary, and Fleeting Echelle Spectroscopy of SN 2023ixf: Monitoring Acceleration of Slow Progenitor Circumstellar Material Driven by Shock Interaction Open
We present high-resolution WIYN/NEID echelle spectroscopy ( R ≈ 70,000) of the supernova (SN) 2023ixf in M101, obtained 1.51 to 18.51 days after explosion over nine epochs. Daily monitoring for the first 4 days after explosion shows narrow…
View article: Simulating Chemical Abundances in the Circumstellar Nebula of the Late Stage Binary RY Scuti
Simulating Chemical Abundances in the Circumstellar Nebula of the Late Stage Binary RY Scuti Open
RY Scuti, thought to be a Wolf–Rayet (WR) progenitor, is a massive post-main-sequence binary star system undergoing Roche-lobe overflow (RLOF). SOFIA (+FORCAST) spectroscopy of the inner, ionized region of RY Scuti’s double ringed toroidal…
View article: The Rise of Network Governance and the Changing Nature of Leadership Power
The Rise of Network Governance and the Changing Nature of Leadership Power Open
Purpose: The general objective of this study was to investigate the rise of network governance and the changing nature of leadership power. Methodology: The study adopted a desktop research methodology. Desk research refers to secondary da…
View article: A Multiwavelength Autopsy of the Interacting Type IIn Supernova 2020ywx: Tracing Its Progenitor Mass-loss History for 100 Yr Before Death
A Multiwavelength Autopsy of the Interacting Type IIn Supernova 2020ywx: Tracing Its Progenitor Mass-loss History for 100 Yr Before Death Open
While the subclass of interacting supernovae (SNe) with narrow hydrogen emission lines (Type IIn supernovae (SNe IIn)) consists of some of the longest-lasting and brightest supernovae (SNe) ever discovered, their progenitors are still not …
View article: Spectroscopy of AT 2016blu’s recurring supernova impostor outbursts
Spectroscopy of AT 2016blu’s recurring supernova impostor outbursts Open
We present spectra of the supernova (SN) impostor AT 2016blu spanning over a decade. This transient exhibits quasi-periodic outbursts with an $\sim$113 d period, likely triggered by periastron encounters in an eccentric binary system where…
View article: JWST/MIRI detects the dusty SN1993J about 30 years after explosion
JWST/MIRI detects the dusty SN1993J about 30 years after explosion Open
Context. Core-collapse supernovae (CCSNe) have long been considered to contribute significantly to the cosmic dust budget. Newly-formed dust in the SN ejecta cools quickly and is therefore detectable at mid-infrared (mid-IR) wavelengths. H…
View article: Spectropolarimetry of SN 2023ixf Reveals Both Circumstellar Material and an Aspherical Helium Core
Spectropolarimetry of SN 2023ixf Reveals Both Circumstellar Material and an Aspherical Helium Core Open
We present multi-epoch optical spectropolarimetric and imaging polarimetric observations of the nearby Type II supernova (SN) 2023ixf discovered in M101 at a distance of 6.85 Mpc. The first imaging polarimetric observations were taken +2.3…
View article: Simulating Chemical Abundances in the Circumstellar Nebula of the Late Stage Binary RY Scuti
Simulating Chemical Abundances in the Circumstellar Nebula of the Late Stage Binary RY Scuti Open
RY Scuti, thought to be a Wolf-Rayet (WR) progenitor, is a massive, post-main-sequence, binary star system undergoing Roche lobe overflow (RLOF). SOFIA (+FORCAST) spectroscopy of the inner, ionized region of RY Scuti's double ringed toroid…
View article: The Long-lived Broadband Afterglow of Short Gamma-Ray Burst 231117A and the Growing Radio-detected Short Gamma-Ray Burst Population
The Long-lived Broadband Afterglow of Short Gamma-Ray Burst 231117A and the Growing Radio-detected Short Gamma-Ray Burst Population Open
We present multiwavelength observations of the Swift short γ -ray burst GRB 231117A, localized to an underlying galaxy at redshift z = 0.257 at a small projected offset (∼2 kpc). We uncover long-lived X-ray Chandra X-ray Observatory and ra…
View article: Luminous Type II Short-plateau SN 2023ufx: Asymmetric Explosion of a Partially Stripped Massive Progenitor
Luminous Type II Short-plateau SN 2023ufx: Asymmetric Explosion of a Partially Stripped Massive Progenitor Open
We present supernova (SN) 2023ufx, a unique Type IIP SN with the shortest known plateau duration ( t PT ∼ 47 days), a luminous V -band peak ( M V = −18.42 ± 0.08 mag), and a rapid early decline rate ( s 1 = 3.47 ± 0.09 mag (50 days) …
View article: Asymmetries and Circumstellar Interaction in the Type II SN 2024bch
Asymmetries and Circumstellar Interaction in the Type II SN 2024bch Open
We present a comprehensive multi-epoch photometric and spectroscopic study of SN 2024bch, a nearby (19.9 Mpc) Type II supernova (SN) with prominent early high-ionization emission lines. Optical spectra from 2.8 days after the estimated exp…
View article: SN 2018is: A low-luminosity Type IIP supernova with narrow hydrogen emission lines at early phases
SN 2018is: A low-luminosity Type IIP supernova with narrow hydrogen emission lines at early phases Open
We present a comprehensive photometric and spectroscopic study of the Type IIP supernova (SN) 2018is. The V band luminosity and the expansion velocity at 50 days post-explosion are −15.1 ± 0.2 mag (corrected for A V = 1.34 mag) and 1400 km…
View article: The Red Supergiant Progenitor Luminosity Problem
The Red Supergiant Progenitor Luminosity Problem Open
Analysis of pre-explosion imaging has confirmed red supergiants (RSGs) as the progenitors to Type II-P supernovae (SNe). However, extracting an RSG's luminosity requires assumptions regarding the star’s temperature or spectral type and the…
View article: Spectroscopy of AT 2016blu's recurring supernova impostor outbursts
Spectroscopy of AT 2016blu's recurring supernova impostor outbursts Open
We present spectra of the supernova (SN) impostor AT 2016blu spanning over a decade. This transient exhibits quasiperiodic outbursts with a $\sim$113 d period, likely triggered by periastron encounters in an eccentric binary system where t…