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S. D. Wyatt

Publications and source records attributed to S. D. Wyatt.

4 recordsLinked to original sources

Teglon: A Pixel-Level Pipeline for Galaxy-Informed Gravitational-Wave Follow-up Planning and Efficiency Analysis

We describe Teglon, an open-source database and analysis pipeline engineered to optimize the search for electromagnetic (EM) counterparts to gravitational wave (GW) sources. Teglon constructs a 3D galaxy completeness metric from an input galaxy catalog and convolves it with the 3D localization volume of a GW event, producing an updated posterior map informed by known galaxy distributions. Using Teglon, users can ingest arbitrary instrument footprints --- or download them directly from the Treasure Map --- to generate dynamic observation plans that seamlessly interpolate between targeted galaxy pointing and region tiling. By focusing efforts on high-probability volumes, Teglon significantly reduces the predicted search area to find EM counterparts and increases observational efficiency, especially for small field-of-view (<= 1 deg^2) instruments like the Nancy Grace Roman Space Telescope. Furthermore, Teglon integrates with Redback to calculate pixel-level model detection efficiencies, enabling custom, event-specific observing strategies or retrospective detection efficiencies on an arbitrary grid of EM transient models. Teglon also supports custom science cases, such as prioritizing Active Galactic Nuclei searches for EM counterparts to binary black hole mergers. Having supported Gravity Collective and related programs from the LIGO-Virgo-KAGRA third observing run (O3) through O4, Teglon is being continuously developed to support O5 and beyond. We document the public repository lineage and packaging, and provide Version 2.0 as an open-source tool for the community.

astro-ph.HE

Windows on the Universe: Establishing the Infrastructure for a Collaborative Multi-messenger Ecosystem

In this White Paper, we present recommendations for the scientific community and funding agencies to foster the infrastructure for a collaborative multi-messenger and time-domain astronomy (MMA/TDA) ecosystem. MMA/TDA is poised for breakthrough discoveries in the coming decade. In much the same way that expanding beyond the optical bandpass revealed entirely new and unexpected discoveries, cosmic messengers beyond light (i.e., gravitational waves, neutrinos, and cosmic rays) open entirely new windows to answer some of the most fundamental questions in (astro)physics: heavy element synthesis, equation of state of dense matter, particle acceleration, etc. This field was prioritized as a frontier scientific pursuit in the 2020 Decadal Survey on Astronomy and Astrophysics via its "New Windows on the Dynamic Universe" theme. MMA/TDA science presents technical challenges distinct from those experienced in other disciplines. Successful observations require coordination across myriad boundaries -- different cosmic messengers, ground vs. space, international borders, etc. -- all for sources that may not be well localized, and whose brightness may be changing rapidly with time. Add that all of this work is undertaken by real human beings, with distinct backgrounds, experiences, cultures, and expectations, that often conflict. To address these challenges and help MMA/TDA realize its full scientific potential in the coming decade (and beyond), the second in a series of community workshops sponsored by the U.S. National Science Foundation (NSF) and NASA titled "Windows on the Universe: Establishing the Infrastructure for a Collaborative Multi-Messenger Ecosystem" was held on October 16-18, 2023 in Tucson, AZ. Here we present the primary recommendations from this workshop focused on three key topics -- hardware, software, and people and policy. [abridged]

astro-ph.IM

Strong Near-Infrared Carbon Absorption in the Transitional Type Ia SN 2015bp

Unburned carbon is potentially a powerful probe of Type Ia supernova (SN) explosion mechanisms. We present comprehensive optical and near-infrared (NIR) data on the "transitional" Type Ia SN 2015bp. An early NIR spectrum ($t = -$9.9 days with respect to B-band maximum) displays a striking C I $\lambda1.0693\,μ\rm{m}$ line at $11.9 \times 10^3$~km s$^{-1}$, distinct from the prominent Mg II $\lambda1.0927\,μ\rm{m}$ feature, which weakens toward maximum light. SN 2015bp also displays a clear C II $\lambda6580$A notch early ($t = -10.9$ days) at $13.2 \times 10^3$~km s$^{-1}$, consistent with our NIR carbon detection. At $M_B = -$18.46, SN 2015bp is less luminous than a normal SN Ia and, along with iPTF13ebh, is the second member of the transitional subclass to display prominent early-time NIR carbon absorption. We find it unlikely that the C I feature is misidentified He I $\lambda1.0830\,μ\rm{m}$ because this feature grows weaker toward maximum light, while the helium line produced in some double-detonation models grows stronger at these times. Intrigued by these strong NIR carbon detections, but lacking NIR data for other SNe Ia, we investigated the incidence of optical carbon in the sample of nine transitional SNe Ia with early-time data ($t \lesssim-$4 days). We find that four display C II $λ$6580A, while two others show tentative detections, in line with the SN Ia population as a whole. We conclude that at least $\sim$50% of transitional SNe Ia in our sample do not come from sub-Chandrasekhar mass explosions due to the clear presence of carbon in their NIR and optical spectra.

astro-ph.HE

The early discovery of SN 2017ahn: signatures of persistent interaction in a fast declining Type II supernova

We present high-cadence, comprehensive data on the nearby ($D\simeq33\,\rm{Mpc}$) Type II SN 2017ahn, discovered within $\sim$1 day of explosion, from the very early phases after explosion to the nebular phase. The observables of SN 2017ahn show a significant evolution over the $\simeq470\,\rm{d}$ of our follow-up campaign, first showing prominent, narrow Balmer lines and other high-ionization features purely in emission (i.e. flash spectroscopy features), which progressively fade and lead to a spectroscopic evolution similar to that of more canonical Type II supernovae. Over the same period, the decline of the light curves in all bands is fast, resembling the photometric evolution of linearly declining H-rich core-collapse supernovae. The modeling of the light curves and early flash spectra suggest a complex circumstellar medium surrounding the progenitor star at the time of explosion, with a first dense shell produced during the very late stages of its evolution being swept up by the rapidly expanding ejecta within the first $\sim6\,\rm{d}$ of the supernova evolution, while signatures of interaction are observed also at later phases. Hydrodynamical models support the scenario in which linearly declining Type II supernovae are predicted to arise from massive yellow super/hyper giants depleted of most of their hydrogen layers.

astro-ph.HE