EM counterparts of GWs: Observation Strategy of SVOM Mission WEI Jianyan@SVOM Team NAOC, Beijing 7th Jan. 2019, Xiamen

Outlines A short introduction about SVOM GW EM counterparts observation strategy

Status of the SVOM mission 2001 SVOM proposed by Chinese side, Eclairs by French side 2006 Phase 0 kick-off meeting (March, Toulouse) Phase 0 review (Sept., Shanghai) CNSA/CNES MoU signed during the President visit (Oct., Beijing) 2007 Phase A kick-off meeting (March, Xi’an) 2008 Phase A review meeting (Oct., Beijing) 2010 SVOM funded by CNSA China 2014 SVOM funded by CNES France 2014 Phase B kick-off meeting (Sept., Shanghai) 2016 Phase B review meeting (July 4-8, Yantai) 2017 Phase C kick-off meeting, and SIR review 2021 SVOM launch at Xichang（西昌）, China

Scientific rationale of a new GRB mission GRB phenomenon Diversity and unity of GRBs GRB phenomenon Diversity and unity of GRBs GRB physics Acceleration and nature of the relativistic jet Radiation processes The early afterglow and the reverse shock GRB physics Acceleration and nature of the relativistic jet Radiation processes The early afterglow and the reverse shock The GRB-supernova connection Short GRB progenitors GRB progenitors The GRB-supernova connection Short GRB progenitors GRB progenitors Cosmology Tracing star formation Re-ionization of the universe Cosmological parameters Cosmological lighthouses (absorption systems) Host galaxies Cosmology Tracing star formation Re-ionization of the universe Cosmological parameters Cosmological lighthouses (absorption systems) Host galaxies Fundamental Origin of high-energy cosmic rays Probing Lorentz invariance Short GRBs and gravitational waves physics Fundamental Origin of high-energy cosmic rays Probing Lorentz invariance Short GRBs and gravitational waves physics

The first stars and the baby Universe Now ～13.8Byrs Evolution after the big bang 1010 109 108 107 106 105 Re-Iron. Big Bang Sun Dark Age last diffusion limit Pop III 3 10 30 100 300 1000 3000 1 + z

Proposed scientific instruments ECLAIRs, the X-ray and soft gamma-ray trigger camera 4-250KeV 2sr (~8000 Sq.deg) GRM, the gamma-ray spectro-photometer 15KeV-5MeV 60 Deg MXT, the micro-channel soft X-ray telescope 0.3-6KeV 65’65’ VT, the visible telescope 400-650nm, 650-950nm 26’26’ GWAC, an array of ground wide angle cameras 500-800nm ~ 5000 Sq.deg. C-GFT, the Chinese ground follow-up telescope 400-1700nm? 25’25’ F-GFT, the French ground follow-up telescope 400-1700nm 30’30’

SVOM scientific instrument arrangement ( SVOM white paper)

ECLAIRs: the trigger camera Main characteristics Coded mask telescope Wide FOV : 2 Sr 6400 CdTe - 1024 cm2 4 keV – 150 keV Anticipated performances Loc. accuracy < 10arcmin 3 arcmin for bright burst 70 GRBs / year

GRM – The Gamma Ray Monitor Main characteristics NaI detectors FOV : 60 Deg. 10 keV – 5 MeV Anticipated performances Loc. accuracy ~ 2° 100 GRBs / year

MXT – The Multi-channel X-ray Telescope Main characteristics MCP X-ray optic FOV ~ 1 deg2 256 x256 PN CCD 0.3 keV – 6 keV Anticipated performances Loc. accuracy < 1 arcmin 20 arcsec for bright GRB 5x10-12 erg cm-2 s-1 in 1000s

VT – The Visible Telescope Main characteristics Ritchey Chretien Ф=40cm FOV : 26 x 26 arcmin2 2 X 2048x2048 CCD 400 - 650 / 650 - 950 nm Anticipated performances Loc. accuracy ~1 arcsec Mv = 22.5 in 300s

Parameters of the GWAC at China Cameras： 40 Diameter： 180mm Focal Length： 220mm Wavelength： 500－800nm Total FoV： ~6000Sq.deg Limiting Mag： 16.0V（5，10sec） Self Trigger: ~13*5sec Prompt optical emission detection down to MV ~ 16.0 (10 s exposure)

Space instruments performances Spectral band Field of View Allocation Accuracy GRBs/yr (Dect. Rate) GRM 30keV-5MeV 2 sr Not applicable ~100 ECLAIRs 4-250 keV 10 arcmin ~70 MXT 0.3-5 keV 65 65 arcmin 30 arcsec ~90% VT 400-650 nm 650-950 nm 26  26 arcsec 1 arcsec ~80%

Pointing strategy: anti solar Sun Night side SVOM orbit (i ~ 30°) About 75% of the GRBs detected by SVOM to be well above the horizon of large ground based telescopes all located at tropical latitudes

Prompt dissemination of the GRB parameters VHF Network

GRB observation strategy Space GRB trigger provided by ECLAIRs at time T0 GWAC GFTs (g, r, i, J, H), LCOGT T0 +1 min 1-2 m robotic telescopes VT (V & R band photometry) MXT (Soft X-ray photometry) T0 + 5 min Ground Multi messenger follow-up

SVOM repartition: useful observing time

Multi-wavelength capabilities of SVOM 102 103 104 105 10 1 -5 1022 1020 1016 1018 1014 1015 Time (s) Log. scale Time (m) Lin. scale Frequency (Hz) Space Ground Slew GRM ECLAIRs MXT VT GWAC F-GFT C-GFT SVOM: also a powerful multi-band observatory for transcients! GWs will be followed within 12 hours.

The strategy for SVOM to observe GW bursts 2015 2019 2022 Error box: ~600 Sq.Deg ~<10 Sq.Deg. GRM Eclairs MXT VT GWAC

GW 170817 / GRB 170817A Would this GRB Have been detected by SVOM? ECLAIRs GRM  Up to 35°: ECLAIRs detects and localizes the GRB ECLAIRs sends an and a slew reques to the satellite  Up to 50°: GRM sends an alert (coarse location) SVOM JSC – December 6th - Paris

GW 170817 / GRB 170817A ToO-MM The associated kilonova would have been easily detected by the VT and the GFTs From T0 + 2 hours and for 10 days SVOM JSC – December 6th - Paris

Status: GWAC 2013-2016: Mini-GWAC for developing Pipelines V1.0; 2014-2015: two 60cm, one 30cm telescopes from GXU and . 2015-2016: the first 18-GWAC system (10 telescopes from NJU); 2017-2018: the 16-GWAC in testing; 22-GWAC waiting for check

An example：2015年12月18日发现---耀星

----------------------------------- GRB （Wang et al. 2013） Flare star （Mini-GWAC 2015） ----------------------------------- T0 T-T0=30 sec GWAC -------------------------- 600秒

2.16-M follow a flare star： 2015年12月18日发现的耀星

So far more than ~60 flare stars were triggered by GWAC/Mini-GWAC

2017 -2018 SVOM Follow-up testing system SVOM CFHT Mini-GWAC，GWACs, F-60A,B CFHT Obs. time SVOM Scheduler Database Server Scientific expertise Xinglong 2.16M Lijiang 2.4M

7 GWs followed during O2 name circular First exposure G268556_20170104 mini:1 + F60B:1 +2h20min G2******************* Mini:1 + GMG:1 +20mins Mini:1 +6h20min -5h29min +2d16hrs +12h30min +12h2min

O1: GW151226 O2: GW170104 6 other events 10 GCN circulars (其中2个使用2.16m 和2.4m ) 8/1/2019

SVOM Follow-up testing system CFHT Obs. time SVOM GWACs, C-GFT GRANDMA Lite Database Server of pointings OT sc. products SVOM Pointing generator Database ZADKO TAROT Xinglong 2M Lijiang 2.4M LCOGT SVOM testing system Follow the strategy of SVOM 2017-2018 Smoothly evolve to SVOM 2021

Voluntaried Facilities SVOM Follow-up System 2021 SVOM ECLAIRs, VT,MXT,GRM GWACs, C-GFT, F-GFT SVOM Scheduler Database Server Scientific expertise Voluntaried Facilities Guaranted time Time to Apply Time to buy TAROT LCOGT 1m CFHT LCOGT 2m XXX Obs Lijiang 2.4M VLT UKIRT XXX Obs XXX Obs XXX Obs XXX Obs Organization of the SVOM Follow-up system, operational in 2021? and based on the attractiveness of SVOM The exchanges between SVOM and its various partners are (will be) defined in the updated SVOM Science Management Plan