M. R. Siebert
A5030501228- Gamma-ray bursts and supernovae
- Astrophysical Phenomena and Observations
- Astrophysics and Cosmic Phenomena
- Stellar, planetary, and galactic studies
- Astronomy and Astrophysical Research
- Pulsars and Gravitational Waves Research
- Astronomical Observations and Instrumentation
- Galaxies: Formation, Evolution, Phenomena
- Astro and Planetary Science
- Spectroscopy and Laser Applications
- Astrophysics and Star Formation Studies
- Global Political and Economic Relations
- Geophysics and Gravity Measurements
- Solar and Space Plasma Dynamics
- Calibration and Measurement Techniques
- Particle Accelerators and Free-Electron Lasers
- Spectroscopy Techniques in Biomedical and Chemical Research
- Neutrino Physics Research
- Atmospheric Ozone and Climate
- Particle Detector Development and Performance
- Magnetic confinement fusion research
- Cosmology and Gravitation Theories
- Spectroscopy and Chemometric Analyses
- Superconducting Materials and Applications
- Medical Imaging Techniques and Applications
Space Telescope Science Institute
2022-2024
University of California, Santa Cruz
2016-2024
On 2017 August 17, gravitational waves were detected from a binary neutron star merger, GW170817, along with coincident short gamma-ray burst, GRB170817A. An optical transient source, Swope Supernova Survey 17a (SSS17a), was subsequently identified as the counterpart of this event. We present ultraviolet, and infrared light curves SSS17a extending 10.9 hours to 18 days post-merger. constrain radioactively-powered resulting ejection neutron-rich material. The fast rise curves, subsequent...
On 2017 August 17, the Laser Interferometer Gravitational-wave Observatory (LIGO) and Virgo interferometer detected gravitational waves emanating from a binary neutron star merger, GW170817. Nearly simultaneously, Fermi INTEGRAL telescopes gamma-ray transient, GRB 170817A. 10.9 hours after wave trigger, we discovered transient fading optical source, Swope Supernova Survey 2017a (SSS17a), coincident with SSS17a is located in NGC 4993, an S0 galaxy at distance of 40 megaparsecs. The precise...
We present constraints on cosmological parameters from the Pantheon+ analysis of 1701 light curves 1550 distinct Type Ia supernovae (SNe Ia) ranging in redshift $z=0.001$ to 2.26. This work features an increased sample size, span, and improved treatment systematic uncertainties comparison original Pantheon results a factor two improvement constraining power. For Flat$\Lambda$CDM model, we find $\Omega_M=0.334\pm0.018$ SNe alone. Flat$w_0$CDM measure $w_0=-0.90\pm0.14$ alone, H$_0=73.5\pm1.1$...
Here we present 1701 light curves of 1550 spectroscopically confirmed Type Ia supernovae (SNe Ia) that will be used to infer cosmological parameters as part the Pantheon+ SN analysis and SH0ES (Supernovae H0 for Equation State dark energy) distance-ladder analysis. This effort is one a series works perform an extensive review redshifts, peculiar velocities, photometric calibration, intrinsic-scatter models SNe Ia. The total number curves, which are compiled across 18 different surveys,...
On 2017 August 17, Swope Supernova Survey 2017a (SSS17a) was discovered as the optical counterpart of binary neutron star gravitational wave event GW170817. We report time-series spectroscopy SSS17a from 11.75 hours until 8.5 days after merger. Over first hour observations ejecta rapidly expanded and cooled. Applying blackbody fits to spectra, we measure photosphere cooling $11,000^{+3400}_{-900}$ K $9300^{+300}_{-300}$ K, determine a photospheric velocity roughly 30% speed light. The...
Photons from a gravitational wave event Two neutron stars merging together generate signal and have also been predicted to emit electromagnetic radiation. When the GW170817 was detected, astronomers rushed search for source using conventional telescopes (see Introduction by Smith). Coulter et al. describe how One-Meter Two-Hemispheres (1M2H) collaboration first locate source. Drout present 1M2H measurements of its optical infrared brightness, Shappee report their spectroscopy event, which is...
Double detonations in double white dwarf (WD) binaries undergoing unstable mass transfer have emerged recent years as one of the most promising Type Ia supernova (SN Ia) progenitor scenarios. One potential outcome this "dynamically driven double-degenerate double-detonation" (D^6) scenario is that companion WD survives explosion and flung away with a velocity equal to its > 1000 km/s pre-SN orbital velocity. We perform search for these hypervelocity runaway WDs using Gaia's second data...
We present panchromatic observations and modeling of supernova (SN) 2020tlf, the first normal type II-P/L SN with confirmed precursor emission, as detected by Young Supernova Experiment transient survey Pan-STARRS1 telescope. Pre-explosion emission was in $riz-$bands at 130 days prior to 2020tlf persisted relatively constant flux until light. Soon after discovery, "flash" spectroscopy revealed prominent narrow symmetric lines ($v_w < 300$ km s$^{-1}$) that resulted from photo-ionization...
Abstract The first James Webb Space Telescope (JWST) Near InfraRed Camera imaging in the field of galaxy cluster PLCK G165.7+67.0 ( z = 0.35) uncovered a Type Ia supernova (SN Ia) at 1.78, called “SN H0pe.” Three different images this one SN were detected as result strong gravitational lensing, each traversing path spacetime, thereby inducing relative delay arrival image. Follow-up JWST observations all three enabled photometric and rare spectroscopic measurements two time delays. Following...
Abstract The JWST Advanced Deep Extragalactic Survey (JADES) is a multicycle program that has taken among the deepest near- and mid-infrared images to date (down ∼30 AB mag) over ∼25 arcmin 2 in GOODS-S field two sets of observations with 1 yr separation. This presented first opportunity systematically search for transients, mostly supernovae (SNe), out z > 2. We found 79 SNe: 38 at < 2, 23 3, 8 3 4, 7 4 5, undetermined redshifts, where redshifts are predominantly based on...
The Foundation Supernova Survey aims to provide a large, high-fidelity, homogeneous, and precisely-calibrated low-redshift Type Ia supernova (SN Ia) sample for cosmology. calibration of the current SN is largest component systematic uncertainties cosmology, new data are necessary make progress. We present motivation, survey design, observation strategy, implementation, first results Survey. using Pan-STARRS telescope obtain photometry up 800 SNe at z < 0.1. This strategy has several unique...
Abstract The merging neutron star gravitational-wave event GW170817 has been observed throughout the entire electromagnetic spectrum from radio waves to γ -rays. resulting energetics, variability, and light curves are shown be consistent with originating merger of two stars, in all likelihood followed by prompt gravitational collapse massive remnant. available -ray, X-ray, data provide a clear probe for nature relativistic ejecta non-thermal processes occurring within, while ultraviolet,...
A spectral-energy distribution (SED) model for Type Ia supernovae (SNe Ia) is a critical tool measuring precise and accurate distances across large redshift range constraining cosmological parameters. We present an improved framework, SALT3, which has several advantages over current models including the leading SALT2 (SALT2.4). While SALT3 similar philosophy, it differs from by having estimation of uncertainties, better separation color light-curve stretch, publicly available training code....
ABSTRACT We present observations of ASASSN-19dj, a nearby tidal disruption event (TDE) discovered in the post-starburst galaxy KUG 0810+227 by All-Sky Automated Survey for Supernovae (ASAS-SN) at distance d ≃ 98 Mpc. observed ASASSN-19dj from −21 to 392 relative peak ultraviolet (UV)/optical emission using high-cadence, multiwavelength spectroscopy and photometry. From ASAS-SN g-band data, we determine that TDE began brighten on 2019 February 6.8 first 16 rise was consistent with flux ∝t2...
Time domain science has undergone a revolution over the past decade, with tens of thousands new supernovae (SNe) discovered each year. However, several observational domains, including SNe within days or hours explosion and faint, red transients, are just beginning to be explored. Here, we present Young Supernova Experiment (YSE), novel optical time-domain survey on Pan-STARRS telescopes. Our is designed obtain well-sampled $griz$ light curves for transient events up $z \approx 0.2$. This...
We present multiwavelength observations of the Type II SN 2020pni. Classified at $\sim 1.3$ days after explosion, object showed narrow (FWHM $<250\,\textrm{km}\,\textrm{s}^{-1}$) recombination lines ionized helium, nitrogen, and carbon, as typically seen in flash-spectroscopy events. Using non-LTE radiative transfer code CMFGEN to model our first high resolution spectrum, we infer a progenitor mass-loss rate $\dot{M}=(3.5-5.3)\times10^{-3}$ M$_{\odot}$ yr$^{-1}$ (assuming wind velocity...
Type Ia supernovae (SNe Ia) are more precise standardizable candles when measured in the near-infrared (NIR) than optical. With this motivation, from 2012-2017 we embarked on RAISIN program with Hubble Space Telescope (HST) to obtain rest-frame NIR light curves for a cosmologically distant sample of 37 SN ($0.2 \lesssim z 0.6$) discovered by Pan-STARRS and Dark Energy Survey. By comparing higher-$z$ HST data 42 at $z<0.1$ observed Carnegie Supernova Project, construct diagram observations...
We present the Young Supernova Experiment Data Release 1 (YSE DR1), comprised of processed multi-color Pan-STARRS1 (PS1) griz and Zwicky Transient Facility (ZTF) gr photometry 1975 transients with host-galaxy associations, redshifts, spectroscopic/photometric classifications, additional data products from 2019 November 24 to 2021 December 20. YSE DR1 spans discoveries observations young fast-rising supernovae (SNe) that persist for over a year, redshift distribution reaching z~0.5. relative...
The modern study of astrophysical transients has been transformed by an exponentially growing volume data. Within the last decade, transient discovery rate increased a factor ~20, with associated survey data, archival and metadata also increasing number discoveries. To manage data at this rate, we require new tools. Here present YSE-PZ, management platform that ingests multiple live streams alerts, identifies host galaxies those transients, downloads coincident retrieves photometry spectra...
Abstract A bright ( m F150W,AB = 24 mag), z 1.95 supernova (SN) candidate was discovered in JWST/NIRCam imaging acquired on 2023 November 17. The SN is quintuply imaged as a result of strong gravitational lensing by foreground galaxy cluster, detected three locations, and remarkably the second lensed found same host galaxy. previous called “Requiem,” therefore new named “Encore.” This makes MACS J0138.0−2155 cluster first known system to produce more than one multiply SN. Moreover, both...
Abstract We present an analysis of the host-galaxy environment Swope Supernova Survey 2017a (SSS17a), discovery electromagnetic counterpart to a gravitational-wave source, GW170817. SSS17a occurred 1.9 kpc (in projection; 10.″2) from nucleus NGC 4993, S0 galaxy at distance 40 Mpc. Hubble Space Telescope ( HST ) pre-trigger image Magellan optical spectroscopy 4993 and location SSS17a, broadband UV-through-IR photometry 4993. The spectrum spectral-energy distribution indicate that has stellar...
Abstract We present panchromatic observations and modeling of the Calcium-rich supernova (SN) 2019ehk in star-forming galaxy M100 ( d ≈ 16.2 Mpc) starting 10 hr after explosion continuing for ∼300 days. SN shows a double-peaked optical light curve peaking at t = 3 15 The first peak is coincident with luminous, rapidly decaying Swift-XRT–discovered X-ray emission <?CDATA ${L}_{{\rm{x}}}\approx {10}^{41}\,\mathrm{erg}\,{{\rm{s}}}^{-1}$?> days; L x ∝ −3 ), Shane/Kast spectral detection narrow H...
Abstract We present photometric and spectroscopic observations of Supernova 2020oi (SN 2020oi), a nearby (∼17 Mpc) type-Ic supernova Ic) within the grand-design spiral M100. undertake comprehensive analysis to characterize evolution SN constrain its progenitor system. detect flux in excess fireball rise model δ t ≈ 2.5 days from date explosion multiband optical UV photometry Las Cumbres Observatory Neil Gehrels Swift Observatory, respectively. The derived bolometric luminosity is consistent...