iPTF Survey for Cool Transients

TL;DR

This paper reports a wide-area survey that discovered various extragalactic transients, highlights the importance of I band observations for identifying cool and dusty transients, and discusses implications for future surveys.

Contribution

It introduces a two-month wide-area survey with the Intermediate Palomar Transient Factory and demonstrates how I band data enhances transient detection and classification.

Findings

Discovered 36 extragalactic transients including rare supernovae and variable stars.

Placed upper limits on the rate of luminous red novae.

Showed that adding I band improves detection of cool and dusty transients in future surveys.

Abstract

We performed a wide-area (2000 deg$^{2}$) g and I band experiment as part of a two month extension to the Intermediate Palomar Transient Factory. We discovered 36 extragalactic transients including iPTF17lf, a highly reddened local SN Ia, iPTF17bkj, a new member of the rare class of transitional Ibn/IIn supernovae, and iPTF17be, a candidate luminous blue variable outburst. We do not detect any luminous red novae and place an upper limit on their rate. We show that adding a slow-cadence I band component to upcoming surveys such as the Zwicky Transient Facility will improve the photometric selection of cool and dusty transients.