What is GRANDMA?

GRANDMA is an international scientific collaboration of physicists and astrophysicists that study gravitational-wave (GW) sources of the local and violent Universe. In particular, we are looking for the signatures of matter being ejected at relativistic speeds in the optical. This web site, developed by the GRANDMA collaboration, is based on the idea of crowdsourcing that encourages any volunteer amateur astronomers to join us in our research efforts. We share a common passion for the breakthrough science of GW astronomy, giving new insights of the past, present and future of the Universe and the formation of heavy elements.

Kilonova-Catcher will allow you to contribute to not only tremendous discoveries in GW astrophysics but also to cosmology and fundamental physics. Your connected to this program will enable you to join us for hunting the optical signature of GW sources, including the collision of neutron stars and black holes and the collapse of the massive stars. This is fundamentally a race with time. Once a GW alert has been received by our system, you will have only 48 hours to catch the optical signature of the event over the sky. For
example, we look for the kilonova emission associated with the coalescence of two neutron stars bound in a compact binary system (BNS). Do not worry, we will help you. But, given
the challenges ahead, we need the participation of a maximum number of participants and your participation can make all the difference.
Be ready for the next observing campaign in mid-2022 and join us now to get ready !


If you have a telescope in your hands or a temporary access to any telescope you are very welcome to join us !

It is simple

  1. Create a kilonova-catcher account and fill in the application form (name, telescope properties, geographic location). These info are important for us. If there is a gravitational-wave event detected, we will send you optimized sky coordinates to observe, knowing your location and your telescope capabilities. Indeed, the sky search area is huge (sometimes a quarter of the total observable sky!) and we need to catch a faint, new source very rapidly because its brightness is declining over hours.                      CREATE MY ACCOUNT (button)
  2. We will explain to you how to receive the observation alerts of the Kilonova-catcher program, how to observe correctly different portions of the sky in which the GW source can be located and how to transmit your observations to GRANDMA and enjoy the excitement of studying science with us. We will be in contact regularly and will alert you if your observations lead to the detection of the optical signature of the gravitational wave sources !

GRANDMA in few words

The Global Rapid Advanced Network Devoted to the Multi-Messenger Addicts (GRANDMA) is a world-wide collaboration with both photometric and spectroscopic facilities, with a large amount of time allocated for observing transient alerts as a telescope network. The GRANDMA consortium includes currently 25 telescopes in 20 observatories, 29 institutions and groups from twelve countries. Thanks to the allocated time available to GRANDMA, the collaboration can cover hundreds of square degrees within 24 hours which allows for a rapid search of the sky localisation area of any GW alert provided by the LIGO/Virgo collaboration. In particular, GRANDMA has the capacity to catch the early stage of the visible components of the post-merger ejected material, potentially with information obtained early on in the color evolution of the transient. While GRANDMA has some shortcomings, for example, very large telescopes are required for deep spectroscopic follow-up, it offers unique worldwide observational capabilities complementary to those of other collaborations.

During the third observational campaign (O3), six wide-field-of-view telescopes were able to cover ∼ 1000 deg 2 down to 18 mag and ∼ 100 deg 2 down to 22 mag in a single night of observations. Interesting transients could be imaged down to ∼ 23 mag in the Northern hemisphere either for photometry and ∼ 22 mag for spectroscopy (e.g GTC). In the future, the entire concept will be expanded, thanks to the possibility to connect any team, any professional or amateur telescope, anytime to GRANDMA.

The prompt full coverage of the transient sky accessible by GRANDMA at a given time is presented just above. In 24 hours, thanks to their distribution across the Earth and especially at eastern longitudes, the GRANDMA network is able to access over 60% of sky (up to more than 72%) during nights to a limiting magnitude of 18 mag about 75% of the time. Due to a lack of western observatories, the sky coverage is reduced to 40-50% during the western nights. All the telescopes are connected to ICARE (Interface and Communication for Addicts of the Rapid follow-up in multimessenger Era) which automatically provides dedicated observation plans to any telescope as soon as a GW alert is received.

During O3, the GRANDMA network followed 90% of the alerts, and employed its unique citizen science program to involve amateur astronomers in following up potential events. The sheer number of alerts followed up by GRANDMA telescopes clearly demonstrated its need for dedicated human organisation, data analysis, and world-wide communicating systems. APC was particularly involved in this success with Sarah Antier (PI of GRANDMA), Alexis Coleiro (PI of the ToO Proposal for GRANDMA on CFHT) and Cyril Lachaud (contributor to the ICARE tools).

The first six months of the Advanced LIGO’s and Advanced Virgo’s third observing run with

GRANDMA Observations of Advanced LIGO’s and Advanced Virgo’s Third Observational Campaign

Multi-messenger astrophysics and the GRANDMA generation

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