EM Follow-up with BlackGEM 2016 Paul Groot Department of Astrophysics/IMAPP Radboud Univerity Nijmegen Why EM? Complementarity! Gravitational Wave information Electromagnetic Wave information - Merger time T0 - Outflow velocities and energetics - Chirp mass of components - Delay times - Inclination of the binary system - Nucleosynthesis in merger material - Remnant geometry: information on binary mass ratio - Rough sky location (~100 sqd) - Accurate position (1”) - Distance - Redshift - Neutron star internal structure - Position in/near a galaxy/stellar populations. - Merger product - Magnetic field strength - Rates of BH/NS mergers - Delay times with respect to star formation - Previous binary evolution 2 Which type of EM? Radio X/γ-rays Optical/IR Rosswog, 2013 3 X-ray, optical or radio? X/γ-rays: Prompt (Δt ~ 0), Beamed (high Г), Fleeting (τ = secs-minutes) Temporal coincidence ✔ Spatial coincidence ✘ Optical: Fast (Δt ~ secs – hours) Isotropic (non-relativistic) Lingering (τ = hours-days) Temporal coincidence ✔ Spatial coincidence ✔ Radio: Slow (Δt ~ weeks – years) Isotropic (shocks with ISM) “Eternal” (τ = months - decade) Temporal coincidence ✘ Spatial coincidence ✔ 4 GW events and sGRBs: same? GW events with AdVirgo/LIGO Population? & Maybe Short Gamma-ray Bursts Events? Number of detected sGRBs within 500 Mpc: 1 in 10 years No GW events and sGRB maybe same population, but not the same events: coincidence rate «1/yr 5 EM follow-up = optical Optical Macronova lightcurve Adapted from Piran, Nakar & Rosswog, 2013 Detecting these macronovae is a challenge: fast, faint and fleeting However, it is possible, but you don't need the LSST: wrong cadence, all-sky not needed 6 Location, location, location... ● GW accuracy: ~100 square degrees ● Needed for large telescopes: 1″ 100 sq.degr. =10⁹ 1arcsec Improvement needed: factor 1 billion 7 Shape and Split +60 Northern Sky Solution n o i t Southern Sky Solution a n i l c e D -20 Courtesy: Branchesi Right Ascension ● Coverage on both hemispheres required ● Elongated shape of error boxes: monolithic fields of view not optimal 8 Requirements & Objectives Science requirements for optical telescope ● SR1. Field of view ≥ 20 sqd ● SR2. Sensitive to ~23 mag in 5 min. ● SR3. Dedicated facility, quick turn-around, follow-up ● SR4. Good (Southern) site: location & sensitivity ● SR5. Versatile: fish-eye, tied, focus mode/colours No such telescope exists, especially in the South Ergo: We have to build it! BlackGEM Array NOVA4 Instrumentation day BlackGEM Phase 1 9 BlackGEM Array Dedicated, optical telescope array for GW events. ● 20 telescopes with 65cm diameter mirrors ● Field of view per telescope: 2 square degrees ● Total field of view: 40 square degrees ● Spatial resolution: 0.57˝ / pixel ● Flexible: fish-eye, tied-array, full zoom ● Location: La Silla observatory of ESO ● Robotically, remote-controlled, triggered by Virgo/LIGO ● Dedicated to GW events! www.blackgem.eu and @BlackGEM_Array Dutch GW Day2013 BlackGEM Phase 1 10 BlackGEM Array Team Project Scientist ('brains'): Gijs Nelemans Instrument Scientist ('golden hands'): Steven Bloemen Principal Investigator ('mouth'): Paul Groot Project Manager ('kicking feet'): Marc Klein Wolt www.blackgem.eu and @BlackGEM_Array Dutch GW Day2013 BlackGEM Phase 1 11 Optical Design Modified Dall-Kirkham design with Field correctors 65cm 9cm x 9cm focal plane 81 Mpix Final Optical design (Jan 2013) for BlackGEM telescopes NOVA4 Instrumentation day BlackGEM Phase 1 12 Performance 1″ Seeing limited between 350 – 900 nm over full 2sq.degr. field NOVA4 Instrumentation day BlackGEM Phase 1 13 Performance 0.65cm on good seeing site = 1.3m on mediocre seeing site Fainter NOVA4 Instrumentation day BlackGEM Phase 1 14 Comparison 45 40 BlackGEM ) d q 35 s ( w e i 30 v f o 25 d l e i f 20 s u o e 15 ZTF n a t n 10 a LSST t BlackGEMP1PTF s PanStarrs1 n I 5 SkyMapper DES 0 VST 0 1 2 3 4 5 6 7 Aperture (m) NOVA4 Instrumentation day BlackGEM Phase 1 15 BlackGEM Array www.blackgem.eu @BlackGEM_Array Dutch Gravitational Wave Day BlackGEM Phase 1 16 BlackGEM @ ESO La Silla, Chile GPO/Marly BlackGEM @ ESO La Silla, Chile Phase & Funding Phase 1: - 4 telescopes - Operational 2015 Phase1 - NOVA, FOM, RU - 3 M€ Phase 2: - 16 telescope more - Operational 2016 - ERC SyG (subm), NWO, External partners? Private donors? - 11 M€ Phase2 Science Objectives BlackGEM Phase 1: ● SO1. Establish the rates of fast transients: R(l,b,z,m,τ, g-r) ● SO2. Detect first Gravitational Wave counterparts Phase1 Science: pre-AdVL Science Objective 1 BlackGEM Phase1 ● SO1. Establish the rates of fast transients: R(l,b,z,m,τ, g-r) We do not know optical sky at these faint magnitudes on timescales of ~hours Phase1 Science: pre-AdVL ???? Kasliwal et al., 2011 On sky in 2015! .