Astrophysics: 2016 highlights and the way forward (My objective view in 10min) Eli Waxman Weizmann Institute of Science Eli Waxman | Weizmann Institute of Science

Eli Waxman | Weizmann Institute of Science

Gravitational Waves: Generation and detection Electro-Magnetic Transmitter Receiver Accelerating electric EM Wave Accelerating electric charge (dipole) charge Gravitational “Transmitter” Gravitational Antenna Accelerating mass GW Accelerating mass (quadrapole) e- e- m Eli Waxman | Weizmann Institute of Science

The challenge: Signal strength GW’s are a Fundamental prediction of General Relativity, 1916 Large masses, 2 x 10 Msun, with extreme acceleration- nearly “touching” black holes freely “floating” test masses 𝑫~𝟏 Giga light years 𝒅~ 𝑹 𝑺 = 𝟐𝑮𝑴 𝒄 𝟐 =𝟑𝟎km, 𝐯~𝐜, 𝒇 𝑮𝑾 ~ 𝒄 𝟐𝝅 𝑹 𝑺 =𝟏 kHz, 𝒅𝑳 𝑳 =𝒉="𝒔𝒕𝒓𝒂𝒊𝒏" 𝑷 𝑮𝑾 ~𝟏 𝟎 𝟐𝟐 𝑷 Sun ~𝟏 𝟎 𝟏𝟏 𝑷 Galaxy > 𝑷 (Obs.) Universe . 𝒉~ 𝑹 𝑺 𝑫 ~𝟏 𝟎 −𝟐𝟏 d m L L+dL m Eli Waxman | Weizmann Institute of Science

Meeting the challenge: LIGO m, mirror L Laser light L+dL m, mirror Change in Escaping Light phase (Michelson interferometer) Eli Waxman | Weizmann Institute of Science

First direct detection of Gravitational Waves A merger of 2x 30 solar mass black holes (derived from 𝒇 𝑮𝑾 ) Distance ~ 1 Giga light years (from 𝒉). Location on the sky poorly known Host galaxy unknown Exact distance unknown Difficult to search for EM “afterglow” Eli Waxman | Weizmann Institute of Science

What did we learn? GW exist as predicted by GR. We already knew, indirectly from the Hulse-Taylor binary neutron star. 30 solar mass black holes exist. Stellar evolution allows the formation of “tight” black hole binaries. 𝑀=1.4 𝑀 Sun 𝑅 ~ 10 km 𝑑=1 0 6 km 𝑀=30 𝑀 Sun 𝑅 ~ 100 km 𝑑 ~ 100 km Eli Waxman | Weizmann Institute of Science

What Next? More black hole binaries, BH formation & evolution. Neutron star mergers More black hole binaries, BH formation & evolution. Improved LIGO + Virgo, LIGO-India, KAGRA: Detection of neutron star mergers, ~(10 deg x 10 deg) error boxes (~2020). Detection of EM afterglows- crucial: Identify host galaxy, Determine exact distance, Matter properties at extreme densities, Production of heavy elements (Au, Pt). Radio to gamma-ray “Afterglow” Eli Waxman | Weizmann Institute of Science

ULTRASAT UV Transient Astronomy Satellite Will revolutionize our understanding of the transient UV universe. EM follow-ups of GW X-rays: rare, 1:100 (jet aiming at us). Radio: ~1yr delay, requires CSM. IR: challenging (wide field inst.). Optical: more difficult than UV. ULTRASAT UV follow-up of GW Instantaneous >50% of sky (8 times better than ground based), in <5 min for >2.5hr. GW error box in a single image. Sensitive to predicted UV. Field of View 210 deg2 Band 220-280 nm Limiting mag 21.9 (5s, 900s) Eli Waxman | Weizmann Institute of Science Target of Opportunity access

Multi-messenger and transient astronomy Astronomy with messengers other than photons: Gravitational waves, Neutrinos. Focus on transient (explosive) events. Driven by fundamental physics and astrophysics questions: The nature of gravity, the origin of neutrino masses… Formation and evolutions of BHs and NSs, explosion mechanisms of stars, production of heavy elements… Enabled by technology advances: GW, neutrinos, Wide field telescopes, fast follow-up capabilities. Eli Waxman | Weizmann Institute of Science