First observation of gravitational wave source, a kilonova: the merger of two neutron stars

Photo: Kilonova observed. Credit: NASA and ESA. Acknowledgment: A.J. Levan (U. Warwick), N.R. Tanvir (U. Leicester), and A. Fruchter and O. Fox (STScI)

On 17 August 2017, the Laser Interferometer Gravitational-Wave Observatory (LIGO) and the Virgo Interferometer both detected gravitational waves from the collision between two neutron stars. Within 12 hours observatories had identified the source of the event within the lenticular galaxy NGC 4993, shown in this image gathered with the NASA/ESA Hubble Space Telescope. The associated stellar flare, a kilonova, is clearly visible in the Hubble observations. This is the first time the optical counterpart of a gravitational wave event was observed. Hubble observed the kilonova gradually fading over the course of six days, as shown in these observations taken in between 22 and 28 August. Credit: NASA and ESA. Acknowledgment: A.J. Levan (U. Warwick), N.R. Tanvir (U. Leicester), and A. Fruchter and O. Fox (STScI)

On 17 August 2017 the Laser Interferometer Gravitational-Wave Observatory (LIGO) and the Virgo Interferometerboth alerted astronomical observers all over the globe about the detection of a gravitational wave event named GW170817. About two seconds after the detection of the gravitational wave, ESA’s INTEGRAL telescope and NASA’s Fermi Gamma-ray Space Telescope observed a short gamma-ray burst in the same direction.

In the night following the initial discovery, a fleet of telescopes started their hunt to locate the source of the event. Astronomers found it in the lenticular galaxy NGC 4993, about 130 million light-years away. A point of light was shining where nothing was visible before and this set off one of the largest multi-telescope observing campaigns ever — among these telescopes was the NASA/ESA Hubble Space Telescope.

Several different teams of scientists used Hubble over the two weeks following the gravitational wave event alert to observe NGC 4993. Using Hubble’s high-resolution imaging capabilities they managed to get the first observational proof for a kilonova, the visible counterpart of the merging of two extremely dense objects — most likely two neutron stars. Such mergers were first suggested more than 30 years ago but this marks the first firm observation of such an event. The distance to the merger makes the source both the closest gravitational wave event detected so far and also one of the closest gamma-ray burst sources ever seen.

“Once I saw that there had been a trigger from LIGO and Virgo at the same time as a gamma-ray burst I was blown away,” recalls Andrew Levan of the University of Warwick, who led the Hubble team that obtained the first observations. “When I realised that it looked like neutron stars were involved, I was even more amazed. We’ve been waiting a long time for an opportunity like this!”

Hubble captured images of the galaxy in visible and infrared light, witnessing a new bright object within NGC 4993 that was brighter than a nova but fainter than a supernova. The images showed that the object faded noticeably over the six days of the Hubble observations. Using Hubble’s spectroscopic capabilities the teams also found indications of material being ejected by the kilonova as fast as one-fifth of the speed of light.

“It was surprising just how closely the behaviour of the kilonova matched the predictions,” said Nial Tanvir, professor at the University of Leicester and leader of another Hubble observing team. “It looked nothing like known supernovae, which this object could have been, and so confidence was soon very high that this was the real deal.”

Connecting kilonovae and short gamma-ray bursts to neutron star mergers has so far been difficult, but the multitude of detailed observations following the detection of the gravitational wave event GW170817 has now finally verified these connections.

“The spectrum of the kilonova looked exactly like how theoretical physicists had predicted the outcome of the merger of two neutron stars would appear,” says Levan. “It ties this object to the gravitational wave source beyond all reasonable doubt.”

The infrared spectra taken with Hubble also showed several broad bumps and wiggles that signal the formation of some of the heaviest elements in nature. These observations may help solve another long-standing question in astronomy: the origin of heavy chemical elements, like gold and platinum. In the merger of two neutron stars, the conditions appear just right for their production.

The implications of these observations are immense. As Tanvir explains: “This discovery has opened up a new approach to astronomical research, where we combine information from both electromagnetic light and from gravitational waves. We call this multi-messenger astronomy — but until now it has just been a dream!”

Levan concludes: “Now, astronomers won’t just look at the light from an object, as we’ve done for hundreds of years, but also listen to it. Gravitational waves provide us with complementary information from objects which are very hard to study using only electromagnetic waves. So pairing gravitational waves with electromagnetic radiation will help astronomers understand some of the most extreme events in the Universe.”

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October 9: Monthly Membership Meeting

New Horizons Spacecraft - Artist's depiction of the spacecraft as it passed through the Pluto/Charon system in July 2015. Image Credit: NASA

New Horizons Spacecraft – Artist’s depiction of the spacecraft as it passed through the Pluto/Charon system in July 2015. Image Credit: NASA

The Monthly Membership Meeting of the Cuyahoga Astronomical Association (CAA) will take place on Monday, October 9, beginning at 7:30 PM. An astronomy presentation is first, followed by a social break, and wrapped up with the club’s business meeting.

The night’s program will be a presentation by CAA member Kai Getrost entitled “New Horizons’ Next Target: The Kuiper Belt.” Getrost enjoyed the adventure of a lifetime, traveling to Argentina as part of a 50-team effort to observe and record data on a rare Kuiper Belt object occultation. A distant object, selected as the next object for study by the New Horizons spacecraft, passed in front of a star; data collected from the event has given astronomers a better understanding of the distance and movement of their target.

Free and open to the public, the program and meeting will take place at the at the Rocky River Nature Center; 24000 Valley Parkway; North Olmsted, Ohio, in the Cleveland Metroparks.

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CAA’s 2017 OTAA Convention

by Bill Murmann, CAA President

I’d like to thank members who joined us and brought food to share and who helped with our Annual Convention and potluck picnic Saturday (Sept. 16) at Letha House Park.  And thanks to our officers and board members-at-large who brought supplies and helped with the picnic — especially Treasurer Ron Palcic who handled ticket sales for our raffle.

We had nice weather and pretty decent night skies for observing, though we had some haze around the horizon and dewy conditions later in the evening.

Special thanks goes to Rich Whisler who did all the grilling for our meal, and to Marianne Wadsworth and Gail Korylak who organized the food line on three tables.  Thanks also to Marianne, and Nancy Whisler who helped clean up.

And thanks to Observatory Director Jay Reynolds who held observatory training and brought a slide show about our solar eclipse program that helped draw an estimated 10,000 guests to Edgewater Park.

I think everyone, including visitors from the Black River and Mahoning Valley astronomy clubs, enjoyed the food and socializing.

Jay Reynolds, Bruce Lane, Dave Watkins, and I were the last to leave at 12:45 AM after listening to groups of coyotes howling in the distance off to the east and the west.

Finally, our sincere appreciation to the following donors who generously provided items for our raffle:

Orion Telescopes & Binoculars
Meade Instrument Corporation
Sky & Telescope Magazine
Knightware, LLC
Bob’s Knobs

Next year’s Annual Convention and picnic will be on Saturday, September 8, 2018.

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Monday, September 11: Monthly Membership Meeting

Image: Artist's concept of Cassini spacecraft at Saturn. Credit: NASA/JPL-Caltech

In this still from the short film Cassini’s Grand Finale, the spacecraft is shown diving between Saturn and the planet’s innermost ring. Credit: NASA/JPL-Caltech

The Cuyahoga Astronomical Association (CAA) will host its monthly meeting at 7:30 PM, Monday, September 11 in the Cleveland Metroparks’ Rocky River Nature Center, North Olmsted. The speaker will be Jay Reynolds who will discuss NASA’s Cassini Mission to Saturn and its finale, set to occur September 15. The program is free and open to the public, no reservations required.

The Cassini spacecraft will make its final approach to the giant planet Saturn this Friday, ending an extremely productive seven-year mission. This encounter will be like no other. This time, Cassini will dive into the planet’s atmosphere, sending science data for as long as its small thrusters can keep the spacecraft’s antenna pointed at Earth. Soon after, Cassini will burn up and disintegrate like a meteor.

In addition to being a research astronomer who teaches at Cleveland State University, Reynolds is CAA’s observatory director. He frequently appears on Cleveland television, hosting a show about astronomy on WKYC, Channel 3.

Following the program, the club’s monthly membership meeting will convene.

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Public observing night at Letha House September 9

Photo: Saturn, by Rochus Hess

Saturn. Credit: Rochus Hess

The Cuyahoga Astronomical Association (CAA) will host a public star party this Saturday (Sept. 9) from 8:00 to 10:00 PM at the Medina County Park District’s at Letha House Park (West). The club’s observatory will be open and CAA members will offer viewing through their personally-owned telescopes.

The weather forecast is looking good for Saturday.  If skies are clear, Jupiter, Saturn, and Neptune will be visible at dusk. Later, Uranus, Saturn, and Neptune will be visible.
The waning Gibbous Moon will clear the horizon at 10:15.  When the sky grows dark enough, and before moonrise, there about 30 Messier objects visible. Messier objects include such things as brighter star clusters, nebulas, and galaxies.
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August 21 solar eclipse: an amazing day

Photo: Crowd watching eclipse. Credit: Alan Studt

A Day of Eclipse Excitement at Edgewater Park. Credit: Alan Studt

by Jay Reynolds

What an amazing day we had.

I don’t think I need to describe the spectacular event we had August 21 at Edgewater Park. While not in the path of totality for the day’s solar eclipse, we still experienced our own version of magic. From the first contact at 1:06 PM to the spontaneous applause at 2:30, we all experienced and shared something very special indeed.

Photo: Group viewing eclipse via projection. Credit: Alan Studt

Sharing the View via “Sun Funnel” Projector. Credit: Alan Studt

It was totally awesome at 2:30 when we were bathed in that eerie light of an 80 percent eclipse. Temperature decrease was noticeable and measurable. A nice break from the oppressive heat of our sun earlier that day.  Also surprising, at 2:45, was the Mass Exodus, leaving only a few remaining for last contact at 3:50 PM.

All of our nonprofit organization friends who said they would be there, were there on time, and ready to go.

A summary of activities:

  • Four Physical activities from City of Lakewood and “Lakewood Alive”
  • Flying airplanes from Discovery Aviation
  • Making “Galaxy Goo” from Spaces Art Gallery
  • Discussing weather with school outreach program, “Wise on Weather”, illustrated by Dick Goddard, was also present.
  • We even had the traveling butterfly enclosure from Put-n-Bay’s Lake Erie Island Nature & Wildlife! (Solar Eclipse and butterflies… J )  This is the same group who does the Stargazing Cruise on Lake Erie.

Also attending was Cleveland Metroparks with their “Nature Tracks” trailer and “Sand Art” craft. NASA Glenn was present with their “Live” truck showing a feed from totality.

We also can’t forget those who showed up extra early to do five segments of: Fox 8’s “Kick’n It with Kenny” morning show: Dave Nuti, Suzie Dills, Nora Mishey, and new member Sarah Drab.  I received nothing but positive feedback for all the work that they did. Those folks came out early and represented our organization extremely well! I was down at Fox 8 the next day and there were numerous compliments.  (They like us.)

Besides, CAA’s own “photographer of awesomeness” Alan Studt, we had guest photographers, David Taggart, and event photographer Sharon Connelly.  Dave has been photographing many of our events since 2005. Sharon and I have worked together for 15 years and had amazing day with us and just loved everyone she met.  Sharon and Dave also pitched in where they could to help.

Photo: Jay Reynolds Interview at Edgewater. Credit: Alan Studt

Jay Reynolds Interview at Edgewater. Credit: Alan Studt

Media Present:

At the event, besides WJW (8), WKYC (3) and WOIO (19) were present for the entire event. Even Scene Magazine did social media throughout the afternoon. We also had news helicopters from WJW (8), and WEWS (5).  A Cleveland Police helicopter was up around us as well.


  • 8/14 Cleveland Plain Dealer Event information
  • 8/16  WTAM Wills & Snyder
  • 8/20  Fox 8 “In the Morning”
  • Fox 8 Maia Belay
  • 8/21 WTAM Wills & Snyder
  • Fox 8 “Kick’n it with Kenny” (4) CAA interviews
  • WOIO – commentary (1)
  • WKYC – Brandon Simmons (2 at event)
  • Fox 8 Stacy Frey (1)
  • Fox 8 Matt Wright (2 at event)
  • 8/22 Fox 8 “In the Morning” Wrap Up
  • Fox Matt Wright – Life of solar glasses
  • Fox Matt Wright – Facebook “Live”- Wrap Up

On the weather side, everyone called for clouds and possible rain. In typical CAA style, it was essentially clear till the end of the event. Forty minutes later, clouds roll in, 10 minutes after that, rain.  CAA was in control!

Photo: Smart Phone held to Eyepiece. Credit: Nancy Whisler

Smart Phone held to Eyepiece. Credit: Nancy Whisler

Besides being the “presenting and organizing agent of record” CAA provided other services and activities…

Photo: Using telescope whilst holding parasol. Credit: Alan Studt

Too Much Sun Might Ruin the Day. Credit: Alan Studt

Everyone on the telescope line did awesome! They were so helpful and generous.

But I must offer special recognition to two ladies who took on the toughest jobs. Nora Mishey, and Sarah Drab.

Photo: Home-Built "Sun Funnel" works Remarkably Well. Credit: Nancy Whisler

Home-Built “Sun Funnel” works Remarkably Well. Credit: Nancy Whisler

Sarah anxiously volunteered to hand out the solar glasses to the guests. None of us realized it would be like “Thunder Dome”! We had to cut off distribution at 10:30 AM because people were taking glasses and leaving and we wouldn’t have any for the guests at 12:30 PM. The line was nearly to the beach! Sarah took a lot of guff! Wow! The demands! The stories! Thank you, Sarah.

Photo: Boy wearing eclipse glasses. Credit: Alan Studt

Youngster is Thrilled by the View of Eclipsing Sun. Credit: Alan Studt

CAA’s own Education Director, Nora Mishey, took a simple craft and “Nora-ized” it into a Tri-C certificate program in the electromagnetic spectrum. People could create special bracelets using UV-sensing beads. They learned about the visible EM spectrum, how we can’t see UV, and why we need to be careful.  Guests received an understandable lesson and a great souvenir.  She never stopped, even when she was stung by a bee or by the oppressive heat.  She was so awesome.

Bottom line: It was an awesome event for the city and for the CAA.

(At the Medina County Park District’s Wolf Creek Environmental Education Center, Bill & Carol Lee and Dave Watson represented CAA with telescopes and park staff presented other Sun-related activities for the public. We were informed by park officials that the park’s gates were closed when attendance topped 1,000. — ed.)

Everyone who was a part of this eclipse, whether it was Edgewater, Wolf Creek, Avon Lake, or just sharing with a neighbor, should be very proud of all of the smiles, enthusiasm for science that was experienced by guests, you served.  CAA continues to live up to the meaning of science outreach and serves as a great example of what a nonprofit can be.
None of this would be possible, without our members’ culture of caring for each other, cooperation and devotion.


Jay Reynolds is astronomy professor at Cleveland State University and serves as the CAA’s observatory director. He regularly coordinates public events in which CAA plays a major part. An estimated 8,000 people were in attendance at Edgewater Park, Cleveland, for the solar eclipse.

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Clouds, clouds, go away!

Photo: Panoramic view of Letha House Park Lake. Photo by James Guilford

August 26: Day’s End – Letha House Park – Photo by James Guilford

After a day featuring fair skies, the evening saw a layer of clouds slide in messing with our Public Night. The slender crescent Moon slowly disappeared into a light smudge. Later, a few stars showed up overhead but, overall, not much to look at. We hope for better weather on September 9, at 8:00 PM when we will host our next Public Night at Letha House Park and our Observatory.

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