Surveys

Collapsars as Sites of r-process Nucleosynthesis: Systematic Photometric Near-infrared Follow-up of Type Ic-BL Supernovae

One of the open questions following the discovery of GW170817 is whether neutron star (NS) mergers are the only astrophysical sites capable of producing r-process elements. Simulations have shown that 0.01–0.1 M $_ødot$ of r-process material could be …

Keck Infrared Transient Survey. I. Survey Description and Data Release 1

We present the Keck Infrared Transient Survey, a NASA Key Strategic Mission Support program to obtain near-infrared (NIR) spectra of astrophysical transients of all types, and its first data release, consisting of 105 NIR spectra of 50 transients. …

Informing the Cataclysmic Variable Sequence from Gaia Data: The Orbital-period-Color-Absolute-magnitude Relationship

The orbital-period (P $_orb$) gap in the population of cataclysmic variables (CVs) informs the theoretical narrative of CV evolution, yet a complete understanding of the driving angular momentum loss mechanisms above and below this gap remains …

DECam-GROWTH Search for the Faint and Distant Binary Neutron Star and Neutron Star-Black Hole Mergers in O3a

Synoptic searches for the optical counterpart to a binary neutron star (BNS) or neutron star-black hole (NSBH) merger can pose significant challenges towards the discovery of kilonovae and performing multi-messenger science. In this work, we describe …

Classification of periodic variable stars with novel cyclic-permutation invariant neural networks

We present Cyclic-Permutation Invariant Neural Networks, a novel class of neural networks (NNs) designed to be invariant to phase shifts of period-folded periodic sequences by means of 'symmetry padding'. In the context of periodic variable star …

GROWTH on S190426c: Real-time Search for a Counterpart to the Probable Neutron Star-Black Hole Merger using an Automated Difference Imaging Pipeline for DECam

The discovery of a transient kilonova following the gravitational-wave (GW) event GW170817 highlighted the critical need for coordinated rapid and wide-field observations, inference, and follow-up across the electromagnetic spectrum. In the southern …

The volumetric rate of normal type Ia supernovae in the local Universe discovered by the Palomar Transient Factory

We present the volumetric rate of normal type Ia supernovae (SNe Ia) discovered by the Palomar Transient Factory (PTF). Using strict data-quality cuts, and considering only periods when the PTF maintained a regular cadence, PTF discovered 90 SNe Ia …

A Machine-learning Method to Infer Fundamental Stellar Parameters from Photometric Light Curves

A fundamental challenge for wide-field imaging surveys is obtaining follow-up spectroscopic observations: there are >10$^9$ photometrically cataloged sources, yet modern spectroscopic surveys are limited to åisebox-0.5ex few× 10$^6$ targets. As we …

Slow-speed Supernovae from the Palomar Transient Factory: Two Channels

Since the discovery of the unusual prototype SN 2002cx, the eponymous class of Type I (hydrogen-poor) supernovae with low ejecta speeds has grown to include approximately two dozen members identified from several heterogeneous surveys, in some cases …

First Searches for Optical Counterparts to Gravitational-wave Candidate Events

During the Laser Interferometer Gravitational-wave Observatory and Virgo joint science runs in 2009-2010, gravitational wave (GW) data from three interferometer detectors were analyzed within minutes to select GW candidate events and infer their …