M. R. Siebert
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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: JWST Discovery of a High-redshift Tidal Disruption Event Candidate in COSMOS-Web
JWST Discovery of a High-redshift Tidal Disruption Event Candidate in COSMOS-Web Open
The rates and properties of tidal disruption events (TDEs) provide valuable insights into their host galaxy central stellar densities and the demographics of their central supermassive black holes. TDEs have been observed only at low redsh…
View article: The Gravity Collective: A Comprehensive Analysis of the Electromagnetic Search for the Binary Neutron Star Merger GW190425
The Gravity Collective: A Comprehensive Analysis of the Electromagnetic Search for the Binary Neutron Star Merger GW190425 Open
We present an ultraviolet to infrared search for the electromagnetic (EM) counterpart to GW190425, the second ever binary neutron star merger discovered by the LIGO-Virgo-KAGRA Collaboration. GW190425 was more distant and had a larger loca…
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: 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: 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: Testing for Intrinsic Type Ia Supernova Luminosity Evolution at z > 2 with JWST
Testing for Intrinsic Type Ia Supernova Luminosity Evolution at z > 2 with JWST Open
The James Webb Space Telescope (JWST) is opening new frontiers of transient discovery and follow-up at high redshift. Here we present the discovery of a spectroscopically confirmed Type Ia supernova (SN Ia; SN 2023aeax) at z = 2.15 with JW…
View article: The JADES Transient Survey: Discovery and Classification of Supernovae in the JADES Deep Field
The JADES Transient Survey: Discovery and Classification of Supernovae in the JADES Deep Field Open
The JWST Advanced Deep Extragalactic Survey (JADES) is a multicycle JWST program that has taken among the deepest near- and mid-infrared images to date (down to ∼30 AB mag) over ∼25 arcmin 2 in the GOODS-S field in two sets of observations…
View article: Properties of high-redshift Type II supernovae discovered by the JADES transient survey
Properties of high-redshift Type II supernovae discovered by the JADES transient survey Open
In this work we estimate the explosion and progenitor properties of six Type II supernovae (SNe) at 0.675 <= z <= 3.61 discovered by the James Webb Space Telescope (JWST) Advanced Deep Extragalactic Survey (JADES) transient survey by model…
View article: An Updated Detection Pipeline for Precursor Emission in Type II Supernova 2020tlf
An Updated Detection Pipeline for Precursor Emission in Type II Supernova 2020tlf Open
We present a new photometric pipeline for the detection of pre-supernova (pre-SN) emission in the Young Supernova Experiment (YSE) sky survey. The method described is applied to SN 2020tlf, a type II SN (SN II) with precursor emission in t…
View article: SN H0pe: The First Measurement of <i>H</i> <sub>0</sub> from a Multiply Imaged Type Ia Supernova, Discovered by JWST
SN H0pe: The First Measurement of <i>H</i> <sub>0</sub> from a Multiply Imaged Type Ia Supernova, Discovered by JWST Open
The first James Webb Space Telescope (JWST) Near InfraRed Camera imaging in the field of the galaxy cluster PLCK G165.7+67.0 ( z = 0.35) uncovered a Type Ia supernova (SN Ia) at z = 1.78, called “SN H0pe.” Three different images of this on…
View article: An Updated Detection Pipeline for Precursor Emission in Type II Supernova 2020tlf
An Updated Detection Pipeline for Precursor Emission in Type II Supernova 2020tlf Open
We present a new photometric pipeline for the detection of pre-supernova (pre-SN) emission in the Young Supernova Experiment (YSE) sky survey. The method described is applied to SN 2020tlf, a type II SN with precursor emission in the last …
View article: Double “acct”: A Distinct Double-peaked Supernova Matching Pulsational Pair Instability Models
Double “acct”: A Distinct Double-peaked Supernova Matching Pulsational Pair Instability Models Open
We present multiwavelength data of SN 2020acct, a double-peaked stripped-envelope supernova (SN) in NGC 2981 at ∼150 Mpc. The two peaks are temporally distinct, with maxima separated by 58 rest-frame days and a factor of 20 reduction in fl…
View article: SN 2021foa: The “Flip-flop” Type IIn/Ibn Supernova
SN 2021foa: The “Flip-flop” Type IIn/Ibn Supernova Open
We present a comprehensive analysis of the photometric and spectroscopic evolution of SN 2021foa, unique among the class of transitional supernovae for repeatedly changing its spectroscopic appearance from hydrogen-to-helium-to-hydrogen do…
View article: Spectroscopic analysis of the strongly lensed SN Encore: constraints on cosmic evolution of Type Ia supernovae
Spectroscopic analysis of the strongly lensed SN Encore: constraints on cosmic evolution of Type Ia supernovae Open
Strong gravitational lensing magnifies the light from a background source, allowing us to study these sources in detail. Here, we study the spectra of a $z = 1.95$ lensed Type Ia supernova (SN Ia) SN Encore for its brightest image A, taken…
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 SNe, 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, which can conden…
View article: The Type I superluminous supernova catalogue I: light-curve properties, models, and catalogue description
The Type I superluminous supernova catalogue I: light-curve properties, models, and catalogue description Open
We present the most comprehensive catalogue to date of Type I superluminous supernovae (SLSNe), a class of stripped-envelope supernovae (SNe) characterized by exceptionally high luminosities. We have compiled a sample of 262 SLSNe reported…
View article: AGN STORM 2. IX. Studying the Dynamics of the Ionized Obscurer in Mrk 817 with High-resolution X-Ray Spectroscopy
AGN STORM 2. IX. Studying the Dynamics of the Ionized Obscurer in Mrk 817 with High-resolution X-Ray Spectroscopy Open
We present the results of the XMM-Newton and NuSTAR observations taken as part of the ongoing, intensive multiwavelength monitoring program of the Seyfert 1 galaxy Mrk 817 by the AGN Space Telescope and Optical Reverberation Mapping 2 (AGN…
View article: Double "acct": a distinct double-peaked supernova matching pulsational pair-instability models
Double "acct": a distinct double-peaked supernova matching pulsational pair-instability models Open
We present multi-wavelength data of SN2020acct, a double-peaked stripped-envelope supernova (SN) in NGC2981 at ~150 Mpc. The two peaks are temporally distinct, with maxima separated by 58 rest-frame days, and a factor of 20 reduction in fl…
View article: AGN STORM 2. VIII. Investigating the Narrow Absorption Lines in Mrk 817 Using HST-COS Observations*
AGN STORM 2. VIII. Investigating the Narrow Absorption Lines in Mrk 817 Using HST-COS Observations* Open
We observed the Seyfert 1 galaxy Mrk 817 during an intensive multiwavelength reverberation mapping campaign for 16 months. Here, we examine the behavior of narrow UV absorption lines seen in the Hubble Space Telescope/Cosmic Origins Spectr…
View article: Discovery of a Relativistic Stripped-envelope Type Ic-BL Supernova at z = 2.83 with JWST
Discovery of a Relativistic Stripped-envelope Type Ic-BL Supernova at z = 2.83 with JWST Open
We present James Webb Space Telescope (JWST) NIRCam and NIRSpec observations of a Type Ic supernova (SN Ic) and its host galaxy (JADES-GS+53.13533-27.81457) at z = 2.83. This SN (named SN 2023adta) was identified in deep JWST/NIRCam imagin…
View article: Discovery of an Apparent Red, High-velocity Type Ia Supernova at z = 2.9 with JWST
Discovery of an Apparent Red, High-velocity Type Ia Supernova at z = 2.9 with JWST Open
We present the James Webb Space Telescope (JWST) discovery of SN 2023adsy, a transient object located in a host galaxy JADES-GS+53.13485−27.82088 with a host spectroscopic redshift of 2.903 ± 0.007. The transient was identified in deep (JW…
View article: SpectAcLE: An Improved Method for Modeling Light Echo Spectra
SpectAcLE: An Improved Method for Modeling Light Echo Spectra Open
Light echoes give us a unique perspective on the nature of supernovae and nonterminal stellar explosions. Spectroscopy of light echoes can reveal details on the kinematics of the ejecta, probe asymmetry, and reveal details of ejecta intera…
View article: Spectroscopic analysis of the strongly lensed SN~Encore: Constraints on cosmic evolution of Type Ia supernovae
Spectroscopic analysis of the strongly lensed SN~Encore: Constraints on cosmic evolution of Type Ia supernovae Open
Strong gravitational lensing magnifies the light from a background source, allowing us to study these sources in detail. Here, we study the spectra of a $z = 1.95$ lensed Type Ia supernova SN~Encore for its brightest Image A, taken 39 days…
View article: JWST Spectroscopy of SN H0pe: Classification and Time Delays of a Triply Imaged Type Ia Supernova at z = 1.78
JWST Spectroscopy of SN H0pe: Classification and Time Delays of a Triply Imaged Type Ia Supernova at z = 1.78 Open
SN H0pe is a triply imaged supernova (SN) at redshift z = 1.78 discovered using the James Webb Space Telescope. In order to classify the SN spectroscopically and measure the relative time delays of its three images (designated A, B, and C)…
View article: The Type I Superluminous Supernova Catalog I: Light Curve Properties, Models, and Catalog Description
The Type I Superluminous Supernova Catalog I: Light Curve Properties, Models, and Catalog Description Open
We present the most comprehensive catalog to date of Type I Superluminous Supernovae (SLSNe), a class of stripped envelope supernovae (SNe) characterized by exceptionally high luminosities. We have compiled a sample of 262 SLSNe reported t…
View article: AGN STORM 2: VIII. Investigating the Narrow Absorption Lines in Mrk 817 Using HST-COS Observations
AGN STORM 2: VIII. Investigating the Narrow Absorption Lines in Mrk 817 Using HST-COS Observations Open
We observed the Seyfert 1 galaxy Mrk817 during an intensive multi-wavelength reverberation mapping campaign for 16 months. Here, we examine the behavior of narrow UV absorption lines seen in HST/COS spectra, both during the campaign and in…
View article: AGN STORM 2: IX. Studying the Dynamics of the Ionized Obscurer in Mrk 817 with High-resolution X-ray Spectroscopy
AGN STORM 2: IX. Studying the Dynamics of the Ionized Obscurer in Mrk 817 with High-resolution X-ray Spectroscopy Open
We present the results of the XMM-Newton and NuSTAR observations taken as part of the ongoing, intensive multi-wavelength monitoring program of the Seyfert 1 galaxy Mrk 817 by the AGN Space Telescope and Optical Reverberation Mapping 2 (AG…