Evryscope Science: Exploring the Potential of All-Sky Gigapixel-Scale Telescopes

Abstract

Low-cost mass-produced sensors and optics have recently made it feasible to build telescope arrays which observe the entire accessible sky simultaneously. In this article we discuss the scientific motivation for these telescopes, including exoplanets, stellar variability and extragalactic transients. To provide a concrete example we detail the goals and expectations for the Evryscope, an underconstruction 780 MPix telescope which covers 8,660 square degrees in each two-minute exposure; each night, 18,400 square degrees will be continuously observed for an average of ≈6 hours. Despite its small 61mm aperture, the system's large field of view provides anétendue which is ∼10% of LSST. The Evryscope, which places 27 separate individual telescopes into a common mount which tracks the entire accessible sky with only one moving part, will return 1%-precision, many-year-length, highcadence light curves for every accessible star brighter than ∼ 16 th magnitude. The camera readout times are short enough to provide near-continuous observing, with a 97% survey time efficiency. The array telescope will be capable of detecting transiting exoplanets around every solar-type star brighter than m V =12, providing at least few-millimagnitude photometric precision in long-term light curves. It will be capable of searching for transiting giant planets around the brightest and most nearby stars, where the planets are much easier to characterize; it will also search for small planets nearby M-dwarfs, for planetary occultations of white dwarfs, and will perform comprehensive nearby microlensing and eclipse-timing searches for exoplanets inaccessible to other planet-finding methods. The Evryscope will also provide comprehensive monitoring of outbursting young stars, white dwarf activity, and stellar activity of all types, along with finding a large sample of very-long-period M-dwarf eclipsing binaries. When relatively rare transients events occur, such as gamma-ray bursts (GRBs), nearby supernovae, or even gravitational wave detections from the Advanced LIGO/Virgo network, the array will return minute-by-minute light curves without needing pointing towards the event as it occurs. By co-adding images, the system will reach V∼19 in one-hour integrations, enabling the monitoring of faint objects. Finally, by recording all data, the Evryscope will be able to provide pre-event imaging at two-minute cadence for bright transients and variable objects, enabling the first high-cadence searches for optical variability before, during and after all-sky events.

The Multi-site All-Sky CAmeRA (MASCARA)

“…A number of surveys with a similar all-sky design, but targeting fainter stars, are in various stages of development and operation, for example HATPI 8 , Evryscope (Law et al 2015) and the Fly's Eye Camera System (Pál et al 2013). These surveys employ a similar strategy of utilizing multiple cameras attached to a single mount to survey large fractions of the visible sky simultaneously, but they employ tracking on this mount as opposed to MASCARA's fixed pointings.…”

How Else Can We Detect Fast Radio Bursts?

“…1, we find m = 15 for a 2 min exposure if η o = 1. This would be eminently detectable by EVERYSCOPE for which the limiting magnitude is 16.4 in 2 min (Law et al 2015).…”

“…Much larger instantaneous fields of view are about to be explored to shallower magnitude limits by ASAS-SN (Holoien et al 2016) and EVRYSCOPE (Law et al 2015). EVRYSCOPE currently samples 8000 deg 2 fields of view every two minutes.…”

RoboTAP: Target priorities for robotic microlensing observations

“…Brokers for processing and filtering the alert stream for rapid response telescopes already exist, for instance the Arizona-NOAO Temporal Analysis and Response to Events System (ANTARES; Saha et al 2016), but more work is needed to address the variety of science cases. The demand for such systems will increase due to emerging projects such as the Evryscope (Law et al 2015), the Zwicky Transient Facility (Smith et al 2014;Bellm 2014), the BlackGEM survey and last but not least the LSST (LSST Science Collaboration et al 2009). The RoboTAP system is just such an automated broker system and a prototypical example for a range of transient science cases.…”