Tag Archives: Science Communication

The first detection of an electromagnetic counterpart to a gravitational wave event

Full AAO Media Release, published at 01:00am Sydney time, 17 October 2017, that I coordinated.

For the first time, astronomers have observed the afterglow of an event that was also detected in gravitational waves. The object, dubbed AT2017gfo, was a pair of in-spiralling neutron stars in a galaxy 130 million light years away. The death spiral was detected in gravitational waves, and the resulting explosion was followed by over 50 observatories world wide, including the AAO and other observatories here in Australia.

On August 17, the Advanced Laser Interferometer Gravitational-Wave Observatory (LIGO), based in the United States, detected a new gravitational wave event, called GW170817.

GW170817 is the fifth source of gravitational waves ever recorded. The first one was discovered in September 2015, for which three founding members of the LIGO collaboration were awarded the 2017 Nobel Prize in Physics.

The GW170817 data are consistent with the merging of two neutron stars and are unlike the four previous events, which were merging black holes.

Artist’s illustration of two merging neutron stars. The narrow beams represent the gamma-ray burst while the rippling space-time grid indicates the gravitational waves that characterize the merger. Swirling clouds of material ejected from the merging stars are a possible source of the light that was seen at lower energies. Credit: National Science Foundation/LIGO/Sonoma State University/A. Simonnet.

The Advanced-Virgo interferometer, based in Italy, was online at the time of the discovery and contributed to the localization of the new gravitational wave burst.

Based on information from LIGO and VIRGO, numerous telescopes immediately sprang into action to determine if an electromagnetic counterpart to the gravitational waves could be detected.

Meanwhile, NASA’s Fermi satellite independently reported a short burst of gamma-rays within 2 seconds of the merger event associated with GW170817, consistent with the area of sky from which LIGO and VIRGO detected their gravitational waves.

This gamma-ray detection at the same time and place triggered even greater interest from the astronomical community and resulted in more intense follow up observations in optical, infrared and radio wavelengths.

A team of scientists within the Dark Energy Survey (DES) collaboration, which includes researchers from the Australian Astronomical Observatory and other Australian institutions, working with astronomers at the Harvard-Smithsonian Center for Astrophysics (CfA) in the U.S., were among the first astronomers to observe the electromagnetic counterpart of GW170817 in optical wavelengths.

Using the 570-megapixel Dark Energy Camera (DECam) mounted at the 4m Blanco Telescope at Cerro Tololo Inter-American Observatory in Chile, DES identified the kilonova AT2017gfo in the nearby galaxy NGC 4993, located only 130 million light years from us, as the optical counterpart of GW170817.

Composite of detection images, including the discovery z image taken on August 18th and the g and r images taken 1 day later. Right: The same area two weeks later. Credit: Soares-Santos et al. and DES Collaboration.

“Because of its large field of view, the Dark Energy Camera was able to search almost the entire region where LIGO/VIRGO expected the gravitational wave source to be, and its exquisite sensitivity allowed us to make detailed measurements of the kilonova – the extremely energetic outburst created by the merging neutron stars,” AAO Instrument Scientist and DES Collaboration member Dr Kyler Kuehn stated.

A kilonova is similar to a supernova in some aspects, but it is different in others. It occurs when two neutron stars crash into each other. These events are thought to be the mechanism by which many of the elements heavier than iron, such as gold, are formed.

“But as impressive as it is, the Dark Energy Camera is only one of many instruments with a front row seat to this celestial spectacle. A lot of effort has gone into preparing dozens of telescopes around the world to search for electromagnetic counterparts to gravitational waves”, Dr Kuehn added.

Simultaneously to the DES study, a large group of Australian astronomers obtained follow up observations of the kilonova AT2017gfo at optical, infrared and radio wavelengths, using 14 Australian telescopes as part of the ARC Centre of Excellence for Gravitational Wave Discovery (OzGrav) and other Australian programs.

Their data are consistent with the expected outburst and subsequent merger of two neutron stars, in agreement with the results derived for GW170817 by the LIGO/Virgo collaboration.

“Before this event, it was like we were sitting in an IMAX theatre with blindfolds on. The gravitational wave detectors let us ‘hear’ the movies of black hole collisions, but we couldn’t see anything. This event lifted the blindfolds and, wow, what an amazing show!!”, A/Professor Jeff Cooke, astronomer at Swinburne University who led many of the observations said.

The Australia team also conducted observations at the 3.9m Anglo-Australian Telescope (AAT), that is managed by the Australian Astronomical Observatory (AAO). Additional archive data from the 6dF survey obtained at the AAO’s 1.2m UK Schmidt Telescope were also used.

“The observations undertaken at the AAT place important constraints on the nature of the environment in which the kilonova occurred”, AAO astronomer Dr Chris Lidman said.

The follow up observations were not scheduled, but the excitement that this event generated in the astronomical community was so large that regular programs were placed on hold.

“Many astronomers dropped any other planned observation and used all the available resources to study this rare event”, said PhD candidate Igor Andreoni (Swinburne University and Australian Astronomical Observatory), first author of the scientific paper that will be published in the science journal “Publications of the Astronomical Society of Australia” (PASA).

The study also reveals that the host galaxy has not experienced significant star-formation during the last billion years. However, there is some evidence that indicates that NGC 4993 experienced a collision with a smaller galaxy not long time ago.

The position of the kilonova AT2017gfo, found in the external parts of NGC 4993, may suggest that the binary neutron star could have been part of the smaller galaxy.

Australian astronomers were thrilled to contribute to both the detection and the ongoing observations of the kilonova AT2017gfo, the electromagnetic counterpart to the gravitational wave event GW170817.

“We have been waiting and preparing for an event like this, but didn’t think it would happen so soon and in a galaxy that is so near to us. Once we were alerted of the gravitational wave detection, we immediately contacted a dozen telescopes and joined the worldwide effort to study this historic event. It didn’t let us down!”, A/Professor Jeff Cooke said.

“It was crucial to have telescopes placed in every continent, including Australia, to keep this rare event continuously monitored”, PhD candidate Igor Andreoni said.

“To me, this gravitational + electromagnetic wave combined detection is even more important than the initial detection that resulted in the Nobel Prize. This has changed the way the entire astronomical community operates”, AAO Instrument Scientist Dr Kyler Kuehn stated.

The first identification of the electromagnetic counterpart to a gravitational wave event is a milestone in the history of modern Astronomy, and opens a new era of multi-messenger astronomy.

More information:

AAO Media Release

AAO Media Release in Spanish / Nota de prensa del AAO en español

LIGO Media Release

DES Media Release

OzGrav Media Release

ESO Media Release

NASA Media Release

Article in The Conversation: “After the alert: radio ‘eyes’ hunt the source of the gravitational waves”, by Tara Murphy and David Kaplan

Article in The Conversation: “At last, we’ve found gravitational waves from a collapsing pair of neutron stars”, by David Blair

Multimedia, videos and animations:

Although there are many videos around there talking about this huge announcement, I particularly like this one by Derek Muller (Veritasium):

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StarFest 2016 in Coonabarabran

After a very intense trip to Spain during July to September, I’m finally back to Australia, just in time to participate in the amazing StarFest 2016 in Coonabarabran, the “Astronomical Capital of Australia”, where Siding Spring Observatory is located.

First, on Friday 30th September we enjoyed the “Science in the Pub” event. I was part of the panel with Elisabete da Cunha (ANU), Fred Watson (AAO), Brad Moore (iTelescope) and David Malin (AAO). We talked about how astronomical images are taken and how to get the colours in Astronomy, with a lot of fun facts (thanks Fred!) about “what our eyes and brain try to see”.

“Science in the Pub” event in Coonabarabran (NSW, Australia) during StarFest 2016, Friday 30th September 2016. Participants are (from left to right): Ángel López-Sánchez (AAO/MQU), Elisabete da Cunha (ANU), Fred Watson (AAO), Brad Moore (iTelescope) and David Malin (AAO). High resolution version here. Photo credit: Steve Chapman (AAO).

StarFest 2016: Science in the Pub

Selfie Elisabete da Cunha and me took just moments before starting the “Science in the Pub” event in Coonabarabran (NSW, Australia) during StarFest 2016, Friday 30th September 2016. High resolution version here. Photo credit: Steve Chapman (AAO).

At the end of this very funny event we received a very special gift: one of my latest astronomical images of the Milky Way over the AAT framed! I was soooo excited, I almost cried, as I didn’t expect this. Thank you very much for the gift!

Me and the gift I received after the “Science in the Pub” event in Coonabarabran (NSW, Australia) during StarFest 2016, Friday 30th September 2016. High resolution version here. Photo credit: Steve Chapman (AAO).

 

On Saturday October 1st was the “Siding Spring Observatory Open Day”. Besides the bad weather, we had plenty of visitors of all ages, from kids to students to elders, all interested about Astronomy and Space. As usual I couldn’t stop talking to everyone, but I also took some photos. As I was jet-lagged (it was just 36 hours after I landed on Sydney) I was very early at the AAT and took some few photos with all ready to go!

StarFest 2016 at the 3.9 AAT

The Anglo-Australian Telescope (AAT) is ready to start StarFest 2016!. Photo taken on Saturday 1 October 2016 during Siding Spring Observatory Open Day, part of StarFest 2016, in Coonabarabran (NSW, Australia). High resolution version here. Photo credit: Ángel R. López-Sánchez (AAO/MQ).

A lot of visitors at the Anglo-Australian Telescope during StarFest 2016 in Coonabarabran (NSW, Australia). Photo taken on Saturday 1 October 2016 during Siding Spring Observatory Open Day, part of StarFest 2016, in Coonabarabran (NSW, Australia). High resolution version here. Photo credit: Ángel R. López-Sánchez (AAO/MQ).

Doug Gray (AAO) explains how the AAT works to visitors of StarFest 2016. Photo taken on Saturday 1 October 2016 during Siding Spring Observatory Open Day, part of StarFest 2016, in Coonabarabran (NSW, Australia). High resolution version here. Photo credit: Ángel R. López-Sánchez (AAO/MQ).

StarFest 2016 at the 3.9 AAT

A wonderful local orchestra was playing famous themes inside the AAT dome during the StarFest 2016. Photo taken on Saturday 1 October 2016 during Siding Spring Observatory Open Day, part of StarFest 2016, in Coonabarabran (NSW, Australia). High resolution version here. Photo credit: Ángel R. López-Sánchez (AAO/MQ).

More photos are available in my album “AAO Outreach” in my Flickr.

However, it was particularly exciting to have a local orchestra playing in the dome! I don’t know who had the idea but was great, so I hope they do it again in the future. I couldn’t help myself and took this video of the orchestra playing two very famous themes: Star Wars and Indiana Jones.

A local orchestra plays the Star Wars & Indiana Jones themes inside the dome of the 3.9m Anglo-Australian Telescope (AAT) at Siding Spring Observatory near Coonabarabran (NSW, Australia) during StarFest 2016. Saturday 1 October 2016. Video credit: Ángel R. López-Sánchez (AAO/MQ).

I really enjoyed this day, and I’m looking forward participating again in StarFest 2017!

“Astronomía para Principiantes”, my new collaboration with radio SBS Australia

Last December I was contacted by journalists from radio SBS Australia in Spanish to be interviewed about my work and my life as a Spanish astronomer in Australia. The interview was prepared by Anna Sagristà, who included it in the section “Latinos en Australia” (Latins in Australia) and released on Sunday 13th December in radio SBS2 97.7 FM. Here is the podcast, in case you want to practice your Spanish:

http://www.sbs.com.au/yourlanguage/api/radio/player/podcast/441762?node=381058

Thanks to this interview I had the chance to talk to them about Astronomy and how scientific research in astronomy works. They were indeed really interested about listening to me talking about stars, planets, galaxies and more, and they liked the way I was answering their questions. Just a couple of days after the interview they phoned me again to talk about a new exoplanets discovery plus the results of the IAU NameExoWorlds contest (yes, we did it! “Estrella Cervantes” is already on the skies!). You can listen to this interview, released on 17th December 2015, here:

http://www.sbs.com.au/yourlanguage/api/radio/player/podcast/442632?node=381786

In early 2016 they asked me to start a collaboration with them. And this way the section “Astronomía para Principiantes” (Astronomy for Beginners) in radio SBS Australia in Spanish was born. This is just a ~monthly 6-8 minutes section talking about an interesting astronomy topic or some recent news about Astronomy. The first podcast was released on Sunday 8th February, we talked about the “predicted IX Planet in the outer parts of the Solar System”. You can listen to it here:

http://www.sbs.com.au/yourlanguage/api/radio/player/podcast/479670?node=408532

Screenshot SBS Australia in Spanish

We still have to work a bit to get it polished, but I’m really happy and excited about this new adventure in Science Communication in Australia.

Additionally last Friday I was also interviewed, of course, about the first observation of gravitational waves, detected by the LIGO experiment in September 2015, but announced in a very expected press conference last Thursday 11th February. The podcast of this interview, which was prepared by Marcia de los Santos, can be found in this podcast:

http://www.sbs.com.au/yourlanguage/api/radio/player/podcast/482376?node=410434

So if you want to practice your Spanish and at the same time know a bit more about Astronomy, you’ll have a chance to listen to me in radio SBS Australia en Español FM 97.7 every month in “Astronomía para Principiantes”. This will be at around 1:15pm on Sundays, but I’ll announce exactly when these are happening via Twitter.

Finally I want to thank journalists at radio SBS Australia in Spanish, and in particular to Anna Sagristà, for the opportunity they are providing me to communicate astronomy to the general public in Australia.