Natasha Van Bemmel
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natasha-vb.bsky.social
Natasha Van Bemmel
@natasha-vb.bsky.social
310 followers 86 following 10 posts
✨ PhD candidate at Swinburne University of Technology | OzGrav
🔭 Time-domain astronomy | Hunting for kilonovae
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natasha-vb.bsky.social
My first first-author paper just dropped on arXiv ✨👩‍🔬🧪🔭

Introducing the KiloNova and Transients Program (KNTraP), a search specifically designed to find a kilonova. Check it out here to see the methods developed to scour the data for kilonova candidates, and what we found:

arxiv.org/abs/2411.16136
Abstract of the KNTraP paper. Text: Compact binary mergers detectable in gravitational waves can be accompanied by a kilonova, an electromagnetic transient powered by radioactive decay of newly synthesised r-process elements. A few kilonova candidates have been observed during short gamma-ray burst follow-up, and one found associated with a gravitational wave detection, GW170817. However, robust kilonova candidates are yet to be found in un-triggered, wide-field optical surveys, that is, a search not requiring an initial gravitational wave or gamma-ray burst trigger. Here we present the first observing run for the Kilonova and Transients Program (KNTraP) using the Dark Energy Camera. The first KNTraP run ran for 11 nights, covering 31 fields at a nightly cadence in two filters. The program can detect transients beyond the LIGO/Virgo/KAGRA horizon, be agnostic to the merger orientation, avoid the Sun and/or Galactic plane, and produces high cadence multi-wavelength light curves. The data were processed nightly in real-time for rapid identification of transient candidates, allowing for follow-up of interesting candidates before they faded away. Three fast-rising candidates were identified in real-time, however none had the characteristics of the kilonova AT2017gfo associated with GW170817 or with the expected evolution for kilonovae from our fade-rate models. After the run, the data were reprocessed, then subjected to stringent filtering and model fitting to search for kilonovae offline. Multiple KNTraP runs (3+) are expected to detect kilonovae via this optical-only search method. No kilonovae were detected in this first KNTraP run using our selection criteria, constraining the KN rate to R<1.8×10^5 Gpc−3 yr−1. Plot showing the volume per night covered by a survey. Volume increases towards the top right corner of the plot. DES survey is shown leftmost, then further right is KNTraP with multiple volumes demonstrating the balance between of number of fields/area on sky observed per night versus the depth achieved, both in dark and bright sky time. Rightmost shown are projected KWFI nightly volumes.
November 26, 2024 at 11:01 PM
natasha-vb.bsky.social
We base expectations on the intrinsic binary neutron star merger (BNS) rate from gravitational wave detectors, but there are multiple rates from different methods (for a summary+fig below: link.springer.com/article/10.1...).

However, observationally we’re looking at <1 per year with current tech
November 22, 2024 at 10:23 PM
natasha-vb.bsky.social
Hello!
My name is Natasha and I’m an astrophysics PhD candidate. I work with data from optical telescopes to search for fast evolving explosions in the sky 💥 On the lookout for the strange and unusual, but mainly I’m searching for kilonovae 🌟🔭👩‍🔬
Context: Me at the ASA Annual Scientific Meeting 2023, with my poster about the KiloNova and Transients Program (KNTraP), a survey optimised to find KiloNova without gravitational wave or gamma-ray burst triggers. Won People’s Choice Award 😎 Description: Photo of a woman standing next to a scientific poster in the style of a detective’s corkboard.
November 22, 2024 at 3:17 AM