RATIR Followup of LIGO/Virgo Gravitational Wave Events

Abstract

Recently we have witnessed the first multi-messenger detection of colliding neutron stars through Gravitational Waves (GWs) and Electromagnetic (EM) waves (GW170817), thanks to the joint efforts of LIGO/Virgo and Space/Ground-based telescopes. In this paper, we report on the RATIR followup observation strategies and show the results for the trigger G194575. This trigger is not of astrophysical interest; however, is of great interests to the robust design of a followup engine to explore large sky error regions. We discuss the development of an image-subtraction pipeline for the 6-color, optical/NIR imaging camera RATIR. Considering a two band ($i$ and $r$) campaign in the Fall of 2015, we find that the requirement of simultaneous detection in both bands leads to a factor $\sim$10 reduction in false alarm rate, which can be further reduced using additional bands. We also show that the performance of our proposed algorithm is robust to fluctuating observing conditions, maintaining a low false alarm rate with a modest decrease in system efficiency that can be overcome utilizing repeat visits. Expanding our pipeline to search for either optical or NIR detections (3 or more bands), considering separately the optical $riZ$ and NIR $YJH$ bands, should result in a false alarm rate $\approx 1\%$ and an efficiency $\approx 90\%$. RATIR's simultaneous optical/NIR observations are expected to yield about one candidate transient in the vast 100 $\mathrm{de}{\mathrm{g}}^2$ LIGO error region for prioritized followup with larger aperture telescopes.

10 pages, 8 figures, 1 table, Accepted to AJ

References in corpus (10)

• GW170817: Observation of Gravitational Waves from a Binary Neutron Star Inspiral
• Multi-messenger Observations of a Binary Neutron Star Merger
• Kilonovae
• Jet Breaks in Short Gamma-Ray Bursts. II: The Collimated Afterglow of GRB 051221A
• Observations of the Naked-Eye GRB 080319B: Implications of Nature's Brightest Explosion
• Parameter estimation for binary neutron-star coalescences with realistic noise during the Advanced LIGO era
• An achromatic break in the afterglow of the short GRB 140903A: evidence for a narrow jet
• Uncovering the Intrinsic Variability of Gamma-ray Bursts
• Galaxy Survey On The Fly: Prospects of Rapid Galaxy Cataloging to Aid the Electromagnetic Follow-up of Gravitational-wave Observations
• GW150914: First search for the electromagnetic counterpart of a gravitational-wave event by the TOROS collaboration

Cited by in corpus (6)

• The Zwicky Transient Facility: Science Objectives
• Machine Learning for the Zwicky Transient Facility
• GROWTH on S190425z: Searching thousands of square degrees to identify an optical or infrared counterpart to a binary neutron star merger with the Zwicky Transient Facility and Palomar Gattini IR
• GROWTH on S190510g: DECam Observation Planning and Follow-Up of a Distant Binary Neutron Star Merger Candidate
• DDOTI Observations of Gravitational-Wave Sources Discovered in O3
• A strategy for LSST to unveil a population of kilonovae without gravitational-wave triggers