Lunar Gravitational-wave Antenna - white paper kick-off

9 Feb 2023, 10:00 → 10 Feb 2023, 14:00 Europe/Rome

Rectorate/Building-Auditorium (GSSI)

The Moon offers a unique environment characterized by an extremely weak seismic background and with very low and stable temperatures in its permanently shadowed regions (PSRs) at the lunar poles. These conditions make it possible to use the Moon as a gravitational-wave (GW) antenna by measuring the small vibrations of the Moon caused by passing gravitational waves. The Lunar GW Antenna (LGWA) would observe GWs in the band 1mHz - 1Hz thus providing the missing link between the space-borne GW detector LISA and terrestrial gravitational-wave detectors. The planning and operation of LGWA requires detailed knowledge of the elastic response of the Moon, depending on its internal structure and near-surface geology at the deployment site, and an assessment of the seismic background in a PSR.

The purpose of this meeting is to start discussions and planning of the LGWA white paper on GW science, multi-messenger astronomy, and lunar science. Registration is only required for people who intend to come in person.

How to reach L'Aquila:

The closest international airports are Rome Fiumicino (FCO) and Rome Ciampino (CIA). 

Rome to L'Aquila:

For people who travel with public transportation, it is recommended to use bus connections. Buses leave from both airports in Rome, and also from the train station Tiburtina. The tickets need to be booked in advance using the web pages of the companies:

https://www.gasparionline.it/en/
https://global.flixbus.com/

One-way bus tickets currently cost less than 20€, and busses from the more distant airport FCO need about 2.5 hours to reach L'Aquila.

The buses from Rome arrive in L'Aquila at Hotel Amiternum. While most locals prefer to take a taxi from the bus station to their home or GSSI, it is also possible to take the last stretch to GSSI by public transportation. Line 2 with end station "terminalbus" has a few stops close to GSSI (GSSI is closest to the third and second-last stations marked in green before "terminalbus" on the Line 2 map): 

https://www.ama.laquila.it/linee-e-orari/elenco-linee-ama/

Staying in L'Aquila:

There are several B&Bs and hotels in the historical part of the city in walking distance to GSSI (see map below). Only very few rooms are typically available with Airbnb.

Thursday, 9 February

14:00 → 14:30 Goals of the white paper

Speaker: Jan Harms (Gran Sasso Science Institute)

WhitePaper.pdf

14:30 → 15:00 LGWA payload and sensitivity model

Speaker: Morgane Zeoli (UCLouvain)

LGWA payload and sensitivity.pptx

15:00 → 15:15 Seismic background reduction

Speaker: Francesca Badaracco (INFN Genova)

LGWA_seismic_background cancellation.pdf

15:15 → 15:30 Discussion

Speaker: Joris van Heijningen (UCLouvain)

DiscussionLGWAwhitepaper.pdf

15:30 → 17:45 Lunar science

Conveners: Alessandro Frigeri (INAF IAPS), Marco Olivieri (INGV)

15:30 Lunar geology

Speaker: Alessandro Frigeri (Istituto Nazionale di Astrofisica (INAF) - Istituto di Astrofisica e Planetologia Spaziali (IAPS), Roma)

The Geology of the Moon in the LGWA Perspective

16:00 Introduction to lunar seismology

Speaker: Marco Olivieri (INGV)

Intro_Seismology_LGWA.pptx

16:15 Lunar GW response

Speaker: Jan Harms (Gran Sasso Science Institute)

Lunar_GW_response.pptx

16:30 Coffee break

16:45 Synthetic models of the lunar seismic field

Speaker: Emanuele Casarotti (INGV)

17:00 Lunar magnetism

Speaker: Massimo Chiappini (INGV)

Chiappini_Lunar-magnetism.PPT

17:15 Discussion

17:45 → 18:45 GW science and multi-messenger astronomy

Conveners: Andrea Maselli (GSSI), Roberto Serafinelli (INAF IAPS)

17:45 Tidal disruption events

Speaker: Elisa Bortolas (Università di Milano Bicocca)

Bortolas_LGWA.pdf

18:15 Can deci-Hz detectors shed light on the true nature of intermediate-mass black holes?

Intermediate-mass black holes (IMBHs) constitute an elusive class of compact objects populating the 10^2-10^4 solar mass range. Aside from the revolutionising discovery of an IMBH weighing 150 solar mass via emission of gravitational waves (GWs) by two stellar-size BHs conducted by the LIGO-Virgo Kagra collaboration, and the observations of a few IMBH candidates with masses > 50,000 solar mass, the IMBH mass range is vastly unconstrained. The very existence of IMBHs is still questionable. Over the next decades, the Einstein Telescope (ET) and LISA could provide us with observations of relatively closeby (redshift < 1) IMBHs in the 10^3-10^4 solar mass range. A detector capable of scanning the unexplored deci-Hz frequency band, thus sitting between ET and LISA, will increase our chance to understand what IMBHs are, enabling us to exquisitely observe IMBHs orbited by a close stellar-size compact companion, a class of GW sources called intermediate-mass ratio inspirals (IMRIs). In this review, I will discuss how future Decihertz Observatories could help us make the next leap in our understanding of the nature of BHs, solving the mystery behind the true nature of IMBHs.

Speaker: Manuel Arca Sedda (University of Padova)

LGWA-WP meeting.pdf

20:00 → 23:00 Dinner at L'Unico Posto

Friday, 10 February

09:00 → 10:00 Introduction to simulation tools

In this session, the GW network simulation tool GWFish, and the seismic simulation tool SPECFEM3D will be presented.

Speakers: Jacopo Tissino (GSSI), Soumen Koley (Gran Sasso Science Institute)

gwfish-2023-02-10.pdf

Specfem3d.pptx

10:00 → 11:45 GW science and multi-messenger astronomy

Conveners: Andrea Maselli, Roberto Serafinelli

10:00 LGWA Sources in Our Galactic Backyard

Compact binary systems composed of white dwarfs (WDs), neutron stars (NSs) and black holes populating our local Universe are ideal targets for space-based GW missions. About a million years prior to the merger, they enter the mHz frequency band, where missions like LISA are expected to operate in the 2030s. Lunar-based projects like LGWA have the potential to further extend the science case of these compact binaries by catching white dwarf and white dwarf-neutron star mergers at higher frequencies. In my talk I will focus on binaries composed of WDs and NSs as gravitational wave sources. I will also discuss their connection to (optical) transient astronomy highlighting multi-messenger opportunities.

Speaker: Valeriya Korol (MPA Garching)

10-02-23-LGWAkickoffWP-Korol.pdf

10:30 Coffee break

10:45 Decihertz Dark Matter: Gravitational Waves from Dark Matter Spikes and Primordial Black Holes

There is overwhelming evidence for the gravitational interactions of Dark Matter (DM), from cosmological observations to the structures of galaxies. Though the nature of DM is still unknown, the direct observation of gravitational waves (GWs) has opened up new avenues to search for and perhaps identify Dark Matter. For example, dense 'spikes' of wave-like or particle Dark Matter may form around intermediate and supermassive black holes. The observation of intermediate and extreme mass ratio inspirals (IMRIs/EMRIs) over long time periods may allow us to tease out the dynamical effects of these DM 'spikes' on lighter inspiraling compact objects. It is also possible that DM may itself be in the form of black holes. These primordial black holes (PBHs) would form from large density fluctuations in the early Universe, long before the formation of the first stars. These may also be probed either directly through their mergers, or through the stochastic background of GWs produced during their formation. I will discuss how GWs can help us to probe these very different types of DM, focusing on what we can learn from the decihertz band.

Speaker: Bradley Kavanagh (IFCA in Santander)

KAVANAGH_LGWA_KickOffMeeting_Feb2023.pdf

11:15 Discussion

11:45 → 12:45 Planning of the white paper

Speaker: Jan Harms (Gran Sasso Science Institute)