engrave

The Into Change Award ceremony in Copenhagen

Sat, 20 Dec 2025 00:00:00 +0000

The award ceremony for the 2025 Into Change award was held in Copenhagen.

The ENGRAVE collaboration has been awarded the Danish Government’s Into Change Award for 2025 in a ceremony at Copenhagen’s Royal Opera House on 15 December 2025.

Her Majesty Queen Mary of Denmark and Minister for Higher Education and Science Christina Egelund presented the award, one of the largest in science at 8,000,000 DKK (over 1 million euros) to Marica Branchesi (GSSI, Italy), Andrew Levan (Radboud University), Elena Pian (INAF, Trieste), Stephen Smartt (University of Oxford, UK), Nial Tanvir (University of Leicester, UK) and Darach Watson (Niels Bohr Institute, Copenhagen) on 15 December. Elena Pian could not be present in person due to unfortunate logistics.

The award goal is “To celebrate the power of European research and innovation in tackling today’s challenges”, and recognises ENGRAVE as a model of scientific excellence and collaboration. The University of Oxford submitted a nomination naming the recipients for leading breakthroughs (both before and after the formation of ENGRAVE) that have established neutron star mergers as cosmic factories of heavy elements, including valuable elements such as gold and platinum, and several thought to be necessary for complex life on Earth.

Speaking in a pre-recorded message, the president of the European Commission Ursula von der Leyen congratulated ENGRAVE, noting that “ENGRAVE is a model of European collaboration and cross-border research. It’s groundbreaking work not only helps to explain the mysterious origins of gold, platinum, and uranium, but it also shows the value of science to help frame our understanding of the world.”

View on the Copenhagen Opera house from the back of the stage, featuring the awardees. Photo credit: Malthe Ivarsson.

The winners of Into Change receive the award. From left to right: Stephen Smartt, Andrew Levan, Darach Watson, Marica Branchesi, Nial Tanvir. Missing: Elena Pian. Photo credit: Malthe Ivarsson.

The Into Change winners converse with Her Royal Majesty Queen Mary of Denmark, and the Minister for Higher Education and Science, Christina Egelund.

Ursula von der Leyen, president of the European Commission, gave a pre-recorded speech. Photo credit: Malthe Ivarsson.

Several contributions were presented - here Danish astronaut Andreas Mogensen. Photo credit: Malthe Ivarsson.

The illuminated hall of the Royal Opera House, where the ceremony took place.

A performance from the Danish Dance Theater. Photo credit: Malthe Ivarsson.

Relaxing after the end of the formal ceremony.

A selection of several ENGRAVE members who could attend the event in person.

ENGRAVE receives the Danish Government’s Into Change Award for 2025!

Wed, 03 Dec 2025 00:00:00 +0000

The ENGRAVE collaboration has been awarded the Danish Government’s Into Change Award for 2025!

To “celebrate the power of European research and innovation in tackling today’s challenges”, the Danish Ministry of Higher Education and Science inaugurated this year the Into Change Award. The ENGRAVE Collaboration has been awarded the inaugural year’s prize, being recognized as a model of scientific excellence and collaboration, which pursues:

joint European coordination of telescopes and data;
open science with free access to results and datasets;
active involvement and training of young researchers through mentoring and live observation networks.

The University of Oxford submitted the nomination, naming Marica Branchesi, Andrew Levan, Elena Pian, Stephen Smartt, Nial Tanvir, and Darach Watson, for leading specific breakthroughs (both before and after the formation of ENGRAVE) that have established neutron star mergers as cosmic factories of r-process elements. The nomination cited a series of papers between 2013 and 2024, from the discovery of the first kilonova candidate (Tanvir et al. 2013), through the GW170817 breakthrough (Abbott et al. 2017a, 2017b) and the seminal ESO papers (Pian et al. 2017, Smartt et al. 2017, Tanvir et al. 2017), to the spectroscopic identification of the first r-process element in the VLT spectra of AT2017gfo (Watson et al. 2019) and the first James Webb Space Telescope spectra of a kilonova with probable heavy r-process elements (Levan et al. 2024).

The teams behind these results founded ENGRAVE to unite astronomers, physicists, and cosmologists in the search for the Universe’s most extreme events – collisions between neutron stars. The award comes with a prize money of 8 million Danish kroner (about 1 million euro). Each member of the winning group receives a personal honourarium of 100,000 Danish kroner. The remaining funds support further research. The Into Change Award will be presented on December 15, 2025 at the Copenhagen Opera House.

Unexpected Passing of Alexander Kann

Mon, 13 Mar 2023 00:00:00 +0000

We are very shocked to hear the news of the unexpected passing of ENGRAVE member David Alexander Kann (Alex). Many of us were talking with him about gamma-ray burst follow-up the night before his death, so we cannot quite comprehend that he is no longer with us. He was an exceptional scientist with an encyclopedic knowledge of GRBs and much besides. Whenever there was some tricky recollection of “can you remember which burst it was that…”, the invariable response was “ask Alex!”. He shared that knowledge freely and easily, and it is a testament to his immense value to the field, just how many of us were in close contact for advice and collaboration in the hours before his death.

There will be time later to honour and acknowledge his myriad scientific achievements. Still, his name will always be remembered hand-in-hand with the progress we have seen in GRBs in the past 20 years. ENGRAVE is a young collaboration, but we were looking forward to his contributions to our operations in O4 and will sorely miss his insight.

Of course, he couldn’t occupy such a central position in the community without being the person people wanted to talk and work with. His enthusiasm was catching. He was part of what made working in the field such an exciting opportunity. Many will regard him as not just a collaborator but a true friend. At this difficult time, we send our condolences to all his family and friends.

Rest easily, Alex, we will miss you.

The ENGRAVE executive committee on behalf of the whole collaboration.

Chryssa Kouveliotou awarded the Shaw prize

Tue, 01 Jun 2021 00:00:00 +0000

We congratulate ENGRAVE member, professor Chryssa Kouveliotou, who was awarded the 2021 Shaw prize in astronomy, jointly with professor Victoria Kaspi, for “their contributions to our understanding of magnetars”. As the name hints, magnetars are highly-magnetised neutron stars: their magnetic fields are much higher (up to a factor of 1000 and more) compared to ordinary neutron stars. They were invoked theoretically first to explain soft-gamma repeaters, very powerful bursts of high-energy radiation observed in the Milky Way and its satellite galaxies. Since then, evidence has amassed confirming their existence and their connection with many classes of astronomical objects.

Magnetars are highly relevant in the field of gravitational wave astronomy. Several models invoke the formation of an ultra-magnetised proto-neutron star (a so-called “proto-magnetar)” following the merger of two lighter neutron stars, which can sometimes collapse shortly after into a black hole. The presence of a magnetar affects the physical processes (including the formation of heavy elements) and the electromagnetic emission due to the merger. It is among the ENGRAVE goals to shed light exactly on such phenomena.

Besides, magnetars are studied in connection with a broad range of phenomena, from long and short gamma-ray bursts, to ordinary and superluminous supernovae, to fast radio bursts, and anomalous X-ray pulsars. They are thus a central component of current astrophysical research. Magnetars are however short-lived (in astronomical terms!), and for that reason they are very rare. Just a couple dozens are known in the Milky Way, out of some 100 billion stars overall!

Professor Kouveliotou has been at the frontline of research of magnetars in all her incarnations, playing key roles in the Compton, BeppoSAX, Swift and Fermi satellites devoted to the discovery and study of gamma-ray transients.

Kouveliotou is current Chair of the Physics Department at George Washington University, in Washington, D.C. (USA), and a retired senior technologist in high-energy astrophysics at NASA’s Marshall Space Flight Center (Huntsville, Al, USA).

The Shaw prize has been awarded yearly since 2004, in the subjects of astronomy, life sciences and medicine, and mathematical sciences. Overall, three women, including Kouveliotou and Kaspi, have been recipients of the Shaw prize in astronomy.

The official announcement with the full motivation can be read here: https://www.shawprize.org/news/announcement-press-conference-2021-press-release.

ENGRAVE scientists awarded JWST time

Wed, 31 Mar 2021 00:00:00 +0000

In the life of professional astronomers, it is a nail-biting moment when the results from a call for proposals are announced. But March 30, 2021, was a very special day, as the Space Telescope Space Institute announced the allocation for the first year (Cycle 1) of the James Webb Space Telescope (JWST). This is the forthcoming next-generation space telescope, due to be launched later this year, on October 31st (update: JWST was finally launched on December 25th, 2021), and a cornerstone mission in the history of astronomy.

We are very proud to announce that scientists associated with ENGRAVE have been awarded time on JWST, for a total of 25 hours. The proposal is titled A Comprehensive View of a Binary Neutron Star Merger, and will have the right to perform “disruptive ToOs” to quickly react to any gravitational wave counterpart discovered during O4. A disruptive ToO is a “target-of-opportunity” observation that can significantly and rapidly alter the planned schedule of the telescope. It is a very demanding operation, both on telescope resources and on the science planning team, so it is allowed only for targets of exceptional importance.

The purpose of the new proposal is to exploit the exquisite sensitivity and spectral coverage of JSWT to explore the visible and especially near-infrared regions of the spectrum, in order to characterise the properties of any kilonova associated with a binary neutron star merger. Many of the heavy elements synthesised during the kilonova explosion emit light in the near infrared range. JSWT will allow us to detect their “signature” in the spectrum, which will help clarify which elements, and how much of them, are present in the kilonova ejecta. In exchange, this will help us to understand better the physics of the merger and of the explosion. Infrared observations are much more sensitive from space, due to the lack of atmospheric absorption and lower background, so JWST will provide an incredible and unprecedented opportunity to study kilonovae.

So, we just need JSWT to be in space! We look forward to its successful launch later this year, and we will spend the time sharpening our theoretical understanding of these enigmatic explosions

The list of all approved JSWT proposals is available here (our proposal is #2395 under the section “Stellar Physics and Stellar Types”): https://www.stsci.edu/jwst/science-execution/approved-programs/cycle-1-go.

The needle and the haystack

Fri, 07 Feb 2020 00:00:00 +0000

No firm electromagnetic counterpart of the first black hole / neutron star merger has been found by ENGRAVE. But the hunt continues!

On February 7th, 2020, the ENGRAVE collaboration released results (https://arxiv.org/abs/2002.01950) on the first black hole / neutron star merger identified by the LIGO and VIRGO gravitational wave detectors, suggesting that there was no detectable electromagnetic counterpart.

The mergers of compact objects, heavier than the Sun but only a few kilometers across, are the primary sources of ripples in the fabric of spacetime. Gravitational wave detectors have observed many mergers of two black holes, and at least two examples where two neutron stars coalesced. However, the third kind of event, the merger of a neutron star with a black hole, had remained undetected until recently. In August 2019, the first such event was observed: S190814bv (later renamed GW 190814 by the LVK collaboration).

Identifying the electromagnetic counterpart of the merger with conventional telescopes would provide a precise sky localisation and help determine its power source.

For example, observations of the first binary neutron star in 2017 revealed that the merger ejected many heavy elements, likely including several times the mass of the Earth in gold. A counterpart to a black hole / neutron star merger would let us test if these systems also produce valuable metals and other heavy elements.

Results revealed by ENGRAVE and associated collaborations present an exhaustive search for the counterpart of S190814bv using a suite of telescopes worldwide. Our facilities include some very wide-field telescopes, such as the ATLAS or Pan-STARRS telescopes in Hawaii, the GOTO telescopes in La Palma and the European Southern Observatory (ESO) premier survey telescopes – the VST optical and VISTA infrared facilities. This was coupled with images of possible host galaxies with large telescopes, such as the Very Large Telescope that could peer even further to look for fainter sources. Looking for this counterpart is like searching for a needle in a haystack.

Together, these searches scoured the region of sky most likely to have hosted the merger, a region approximately as large as 30 times the apparent size of the full Moon. They identified a myriad of new transient sources, each of which was meticulously ruled out as the counterpart of the merger. Ultimately, no convincing counterpart was found. This merger was almost ten times further away than the binary neutron star merger which caused such excitement in 2017, and so it may just be that the counterpart was fainter than what our telescopes could detect. Alternatively, it is quite likely that the neutron star didn’t “eject” any matter at all, but was instead swallowed directly by the black hole.

“We had this beautiful set of observations, from an extremely diverse range of telescopes spread all around the world, but we could find no convincing new transient sources related to the GW event object in the images. How likely had we missed something that was either too faint or just faded too quickly? We have been working hard to answer precisely this question, which is what turns our non-detection into actual information about the nature of the explosion: we now can tell rather accurately what did NOT happen as the black hole and the neutron star merged. All evidence points in the same direction: the black hole likely swallowed the neutron star in a single bite, leaving no matter outside to shine”, says Om Sharan Salafia, one of the authors who followed this work most.

Morgan Fraser, also closely involved in this work, complements: “It has been a fantastic achievement for the ENGRAVE collaboration to bring more than two hundred astronomers together to work on a single goal. The discovery of S190814bv last year saw a burst of activity when a few square degrees of the sky briefly became one of the most intensively monitored regions of space in history. While we didn’t see any light from the merger, we can still use this information to constrain how neutron stars and black holes merge. And crucially, after the experience with S190814bv, ENGRAVE is now even better prepared for the next gravitational wave event that LIGO/VIRGO will detect.”

“We obtained spectacular images from the VLT both in the optical (with the FORS2 instrument) and in the near infrared (with HAWK-I), targeting known galaxies within the localisation region of S190814bv.

We cannot deny that the lack of detection of the optical counterpart of the NS-BH event left us a little disappointed despite our search for the faintest variable sources reached very deep limits. However these non-detection limits allow us to set important constraints on the predictions of theoretical models for NS-BH merger and to optimize the strategy of the search campaigns for events only detectable with the largest telescopes in the world” continues Maria Teresa Botticella, who coordinated the analysis of our images.

It is hard to reach solid conclusions based on a single event, so we need more objects to be sure that our conclusions are general, and perhaps even more intensive follow-up of these events. We have learnt much from S190814bv, and stand ready to launch new searches for the next events. The hunt is never over!

The final, accepted version of the ENGRAVE paper is available here (Ackley et al. 2020, A&A 643, A113): https://doi.org/10.1051/0004-6361/202037669

2nd ENGRAVE collaboration meeting

Fri, 15 Nov 2019 00:00:00 +0000

The second ENGRAVE all-hands meeting was held on November 12-14th, 2019, at the INAF Capodimonte Astronomical Observatory, Naples, under beautiful blue skies and the shadow of Vesuvius.

We thank the local organisers led by Maria Teresa Boticella, Aniello Grado and their team of Fabio Ragosta, Pietro Schipani, Andrea Di Dato, Maria Teresa Fulco, A. Maiorica and R. Aiello.

ENGRAVE thanks GRAWITA and the Instituto Nazionale di Astrofisica (INAF) for their generous support of the meeting, and the Director of the Capodimonte Observatory, Marcella Marconi, for hosting us.

The mystery of AT 2019osy

Tue, 24 Sep 2019 00:00:00 +0000

While searching for a counterpart to the gravitational wave event from August 14 (S190814bv), astronomers using the ASKAP telescope discovered an unusual transient in the radio band: AT 2019osy. Its nature is unclear, but its location within a galaxy and a rising radio flux made it worth searching for a kilonova event.

ENGRAVE set out to clarify the issue, using two of the most powerful facilities in the world: the Hubble Space Telescope for the visible band, and the ALMA interferometer, the world largest and most sensitive instrument for microwave radiation. These telescopes provide exquisite spatial resolution, allowing them to obtain extremely sharp images of both the transient and of its host galaxy. Thanks to these two telescopes, it was possible to pinpoint the location of AT 2019osy to the very center of the galaxy. Such a precise positional coincidence opens the option that the emission is in fact due to an active nucleus - unrelated to the GW event.

We cannot firmly rule out this option yet. Studying the temporal variability of the object can help clarify its nature. This is being done with further ALMA observations. The main goal of the Hubble Space Telescope observation was to look for the presence of infrared emission consistent with a kilonova event. Unfortunately, no candidate was detected, but, as you can see, we obtained a beautiful view of a spiral galaxy seen edge-on. Studying the properties of the host galaxy is another way to help characterise the nature of the radio transient.

This campaign showcases the painstaking work necessary to spot genuine GW counterparts, a task which is similar to the proverbial looking for a needle in a haystack. Also, understanding which other objects, unrelated to GW counterparts, can pose as fake conterparts is an important task to optimise and refine our search strategies. The Universe always finds a way to surprise us, even though not always it’s the one we were looking for!

References:

LIGO Scientific Collaboration and the Virgo Collaboration, GCN Circular #25324.
Stewart et al., GCN Circular #25487
Bauer et al., GCN Circular #25801

First light of ENGRAVE and a potential NS-BH merger

Tue, 20 Aug 2019 00:00:00 +0000

A few months ago, the hunt for gravitational waves as part of the third observing run (O3) was initiated by the Advanced LIGO and Advanced Virgo gravitational-wave detectors on April 1, 2019. Both detectors have been upgraded since they were last in operation and have already reported more than 20 gravitational-wave candidate events of either merging binary black holes or merging binary neutron stars. On August 14, for the first time, they reported the likely detection of a neutron star colliding with a black hole, called S190814bv. This initiated an intensive search campaign for a potential electromagnetic counterpart, and the ENGRAVE collaboration could for the first time report observations of candidates to this event using the Very Large Telescope in Chile. A large number of potential candidates were reported in the following days, detected by several teams using telescopes around the world. After carefully considering the most likely candidates to the gravitational-wave detection, the ENGRAVE’s operations team obtained imaging and spectroscopic data of a few of the newly reported transients to classify the physical nature of these. The observations were reported in the first official GCN by ENGRAVE. The data analysis is still ongoing, but so far no viable candidates have been identified. Nevertheless, this was the first time ENGRAVE was in action, heralding a fruitful collaboration going forward.

A negative result is still a result, and our observations allow to set deep limits to the kind of radiation emitted by these explosions, which had not been constrained previously. For example, for some parameters of the black hole (mass, rotation, …), the neutron star is swallowed into the black hole without being disrupted, and no ejected material and electromagnetic emission is expected after the merger. Or it may simply be that the emitted light was too faint to be detected. The latter point is somehow complicated by the larger distance of this event (~270 Mpc) compared to the first electromagnetic detection of GW170817 at ~40 Mpc. However, if the event S190814bv was as bright as GW170817 we would have detected it, if it was located in any of the targeted candidate host galaxies.

AT2017gfo Data Release

Mon, 25 Feb 2019 00:00:00 +0000

ESO’s VLT + X-Shooter observed AT2017gfo nightly for 10 consecutive nights after discovery providing complete spectral coverage from 3300 Angstroms to 2.5 microns. The data were published in the papers Pian et al. 2017, Nature, 551, 67 and Smartt et al. 2017, Nature, 551, 75. The ENGRAVE collaboration have fully reduced all the data in a uniform manner (data reduced by J. Selsing) and spectrophotometrically calibrated to published photometry of AT2017gfo (by J. Gillanders).

Various versions of the spectra are provided from the native dispersion of X-shooter to flux calibrated, smoothed, de-reddened versions. This compilation of spectra are available publicly and we encourage use of these data products as the definitive reductions and calibrations of the ESO X-Shooter campaign on AT2017go. The plots above and below illustrate the excellent agreement between the published photometry and the recalibrated X-Shooter spectral products and the high quality of the data products. For reference, we also include the HST spectra from Tanvir et al. (2017, ApJ, 848, L27).

These spectra represent full wavelength, daily coverage of AT2017gfo and we encourage use of these versions of the spectra as the definitive data products. They are available to download here.

Users must cite the original papers Pian et al. 2017, Nature, 551, 67 and Smartt et al. 2017, Nature, 551, 75 when using these X-Shooter data, and/or Tanvir et al. (2017, ApJ, 848, L27) when using the HST spectra. Users should check the file README.txt.

A compilation of homogenised photometry of AT2017gfo from various published sources is also provided and citations for the use of this file is included (see AT2017gfo_phot_compiled_sjs.dat).

X-Shooter and HST spectra of AT2017gfo (+5.40d - +7.40d) with accompanying photometry

X-Shooter and HST spectra of AT2017gfo (+8.40d - +10.40d) with accompanying photometry