About KPED

After the significant success of the Robo-AO program on the Kitt Peak 84 inch telescope, a program which uses adaptive optics to take images of quality comparable to what is done in space, there is a new camera on the telescope. The Kitt Peak Electron Multiplying CCD (EMCCD) demonstrator (KPED), which is a simple instrument consisting of a EMCCD and a filter wheel, which will do rapid and sensitive photometric measurements of several classes of objects. EMCCDs use a high gain, or electron multiplication (EM) register, which is a second stage of readout that amplifies electrons in a process known as avalanche multiplication. At the cost of pixel charge capacity, much higher signal-to-noise ratios are possible above and beyond conventional CCD or CMOS detectors. The goal for the system is to allow for high cadence photometry with a large field of view with seeing-limited image quality.

The KPED team thanks the National Science Foundation and the National Optical Astronomical Observatory for making the Kitt Peak 2.1-m telescope available. We thank the observatory staff at Kitt Peak for their efforts to assist Robo-AO KP operations. The KPED team thanks the National Science Foundation, the National Optical Astronomical Observatory and the Murty family for support in the building and operation of KPED. In addition, they thank the CHIMERA project for use of the EMCCD.

Summary Presentation

Movie of KPED observations of 6.9 minute white dwarf binary (sped up)

Accomplishments

Found: fastest eclipsing binary, a valuable target for gravitational wave studies

NOAO Jul 2019

Highlight of Kitt Peak 2.1m and KPED’s role in 6.9 minute system discovery

The plunging pirouette of two low-mass stars

Nature Astronomy Jul 2019

Nature Astronomy Highlight of 6.9 minute system: Astronomers using the Zwicky Transient Facility have discovered two white dwarfs orbiting each other every 6.9 minutes. But there is nothing transient about the gravitational waves emitted from this binary: the stars will produce persistent ripples in spacetime for millennia.

Astronomers Just Discovered Two Stars Orbiting Each Other Faster Than Any We’ve Seen

Science Alert Jul 2019

6.9 minute system highlight at sciencealert.com

Scientists Spot Two Dead Stars Locked in a Dizzying Dance

Space.com Jul 2019

6.9 minute system highlight at space.com

Evolution

KPED Fully Robotic Observing

Sep 2019 – Present

Since the end of the monsoon season, KPED has been fully robotic, no longer relying on input from the remote astronomers, outside of supplying potential targets before the night begins. This mode of operation is essential for steady follow-up of the white dwarf binaries, where timing of eclipses over months to years enable the measurement of the orbital change in frequency due to the emission of gravitational waves.

KPED Remote Observing

Jun 2018 – Sep 2019

For a bit more than a year, a small group of astronomers used KPED to follow-up gravitational-wave sources. One of the most exciting areas of astronomy right now is the search for gravitational-wave counterparts to compact binaries, and KPED has played an important role in follow-up in the latest observing run (https://arxiv.org/abs/1907.12645). In addition, observing white dwarfs in binary systems, emitting gravitational waves and thereby losing orbital angular momentum, is a probe of gravity using inherently quantum objects, and two of these objects have been published using KPED data (https://arxiv.org/abs/1910.11389, https://arxiv.org/abs/1907.11291). Other sources, including magnetic white dwarfs with pulsation periods below 5 minutes and pulsating white dwarfs with pulsation periods of 3 minutes have been found and characterized.

KPED Installation and Commissioning

Jun 2018 – Jun 2018

After the significant success of the Robo-AO program on the Kitt Peak 84 inch telescope, a program which uses adaptive optics to take images of quality comparable to what is done in space, KPED is installed on the telescope. KPED, coupled with a fully roboticized telescope, is ideal for follow-up of gravitational wave sources, including short duration transient sources found coincident with GW observatories, as well as white dwarf binary candidates identified by large field-of-view all-sky surveys such as the Zwicky Transient Facility (ZTF). During commissioning, a candidate 6.9 minute period white dwarf binary is discovered with the help of KPED, resulting in a future Nature paper (https://arxiv.org/abs/1907.11291).

KPED Design and Fabrication

Jan 2018 – Jun 2018

The Kitt Peak Electron Multiplying CCD (EMCCD) demonstrator (KPED), which is a simple instrument consisting of a EMCCD and a filter wheel, is designed to do rapid and sensitive photometric measurements of several classes of objects. EMCCDs use a high gain, or electron multiplication (EM) register, which is a second stage of readout that amplifies electrons in a process known as avalanche multiplication. At the cost of pixel charge capacity, much higher signal-to-noise ratios are possible above and beyond conventional CCD or CMOS detectors. The goal for the system is to allow for high cadence photometry with a large field of view with seeing-limited image quality.

Robo-AO on Kitt Peak 2.1m

Nov 2015 – Jun 2018

Robo-AO is the first autonomous laser adaptive optics system and science instrument operating on sky. The system robotically executes large scale surveys, monitors long-term astrophysical dynamics and characterizes newly discovered transients, all at the visible diffraction limit.