Gravitational Waverelated projects at OAR VirgoLIGO e LISA

Gravitational Wave-related projects at OAR Virgo/LIGO + e. LISA Sources Multimessenger follow up Instrumentation Virgo EGO Science Forum (VESF) Luigi Stella (with thanks to Enzo Brocato and Marica Branchesi for several slides)

Double White Dwarf Binaries (AM CVn-like) Nov 2002 Nov 2001 RXJ 0806. 3+1527: a double degenerate binary system (2 WDs) with an orbital period of 5. 4 min !! One of the best target for gravitational wave Detection by e. LISA

Magnetars: Bursts - energy release ~1038 -1041 ergs subsecond duration often emitted in bunches

SGR 1806 -20: Giant Flare of 2004 Dec 27 (Palmer et al. 2005 Hurley et al. 2005) Moon reverberation seen ! (Mereghetti et al. 2005)

The B-field of Magnetars Very strong internal B-fields in a newborn differentially rotating fast-spinning neutron star For initial spin periods of Pi∼ 1– 2 ms, differential rotation can store ∼ 1052(Pi/1 ms)2 ergs, that can be converted into a magnetic field of up to 3 x 1017 (Pi/1 ms)-1 G. (efficient dynamo might be limited to ~3 x 1016 G) (Duncan & Thompson 1992) Bt Bd Fast spin (few ms) and differential rotation generate internal toroidal field B > 10 15 G Bd ~ 1014 -15 G outer dipole field (spin-down, pulsations) inferred from spin-down rate (and confirmed through the energetics and fast variability properties of the “ringing tail” of Giant Flares from SGRs) Bt > 1015 G inner toroidal field (energy reservoir): lower limit from: L(persistent) x age ~ 10 47 ergs

Newborn Magnetars as Gravitaional Wave Sources ~ 1 week, ~ 10 8 cycles 2 x 1016 G 6 x 1016 G (for Virgo Cluster distance, 20 Mpc) - GW signal at ~1 k. Hz evolving in 1 week - Consider initial spin period of 2 ms Most promising region is Bt > 1016. 5 G and Bd < 1014 G - Required no. of templates is very large Expected magnetar birth rate in the ~2000 galaxies of Virgo: ~ 1 yr -1 ! Potentially Very Interesting GW Event Rate in Advanced LIGO/Virgo-class instruments

Short Gamma-Ray Bursts • GRBs duration distribution is bimodal (e. g. Briggs et al. 2002) – 0. 1 -1 s -> Short bursts – 10 -100 s -> Long bursts • Short GRBs are harder than long GRBs (e. g. Fishman & Meegan, 1995; Tavani 1996).

GRB 970228: the 1 st X-ray and Optical afterglow • • Fast follow up with the Beppo. SAX-NFIs (8 hr) led to the discovery of a bright unknown Xray source. A second pointing 3 days after showed that source had faded. (Costa, et al. , 1997) • Accurate (~1 arcmin) X-ray position led to the identification of a fading optical source from ground based telescopes (Van Paradijs, et al. , 1997) (Pedichini et al 1997)

GRB 970508: the 1 st redshift • • Images in the 2 -10 ke. V range by the BSAX WFC (10 -200 sec after the GRB) and by the BSAX MECS (6 hrs and 3 days). The BSAX observation led the Caltech group to the measurement of the first redshift and Frail et al to the discovery of the 1 st radio afterglow and direct measurement of relativistic expansion GRBs have: X-ray afterglows > 90% Optical afterglows ~ 40% - 50% Radio afterglows ~ 35% - 40% Metzeger et al. , 1997 Long GRBs: cosmological distances !

Swift Instrumentation Burst alert telescope (BAT) 10 -150 ke. V X-ray telescope (XRT) 0. 3 -10 ke. V UV-optical telescope (UVOT) U-I - USA, I, UK mission dedicated to GRB Science 1. 2. 3. 4. Burst Alert Telescope triggers on GRB, calculates position to < 4 arcmin Spacecraft autonomously slews to GRB position in 20 -70 s X-ray Telescope determines position to < 5 arcseconds UV/Optical Telescope images field, transmits finding chart to ground BAT Burst Image T<10 s, < 4' XRT Image UVOT Image BAT Error Circle T<100 s, < 5'' T<300 s

Host Galaxies of Short GRBs - Short GRBs are located inside or close to early type galaxies with low star formation activity, BUT some are found in galaxies with star formation activity. GRB 050509 b GRB 050709 - Short GRBs are NOT associated to Supernovae - Short GRB are at cosmological distances but at smaller redshifts than Long GRBs - Short GRB are ~100 times less energetic than Long GRBs

Coalescing binary models Association of Short GRBs to low SFR galaxies + absence of SN : Long delay (Gyrs) between the formation of the neutron star (or black hole) and the Short GRB explosion. Merging (or Coalescing) binary models for Short GRBs Neutron Star + Neutron star (NS-NS) or Neutron Star + Black hole (NS-BH) Strong Gravitational Wave Sources !

To summarise - Newborn Magnetars are interesting GW sources for Advan LIGO/Virgo-class instruments. Newborn magnetars can be detectable from the whole Virgo Cluster, where their birth rate is ~1 mag - Short Gamma Ray Burst, if (for the most part) due to coale binaries, provide an independent way of estimating the NS NS-BH merging and GW detection rates Evidence that the local Short GRB rate is dominated and NS-BH binaries formed in globular clusters throu dynamical interactions: this increases the local rate a chances of detecting GWs from these events

Kilonovae and Radio Flares Significant mass (0. 01 -0. 1 mo) is dynamically ejected during NS-NS NS-BH mergers at sub-relativistic velocity (0. 1 -0. 2 c) (Piran et al. 2013, MNRAS, 430; Rosswog et al. 2013 , MNRAS, 430) EM signature similar to Supernovae Macronova – Kilonova short lived IR-UV signal (days) powered by the radioactive decay of heavy elements synthesized in the ejected outflow Kulkarni 2005, astro-ph 0510256; Li & Paczynski 1998, Ap. JL, 507 Metzger et al. 2010, MNRAS, 406; Piran et al. 2013, MNRAS, 430 RADIO REMNANT long lasting radio signals (years) produced by interaction of ejected sub-relativistic outflow with surrounding matter Piran et al. 2013, MNRAS, 430 12

Kilonovae Light Curves Source at distance of 200 Mpc 5 Red magnitude 10 Kilonova model afterglow peaks about model afterglow a day after the merger/GW event NS-BH Piran et al. NS-NS Piran et al. Blackbody Metzger. et al. Fe-Opacity Metzger et al. 15 20 Major uncertainty OPACITY of “heavy r-process elements” 25 30 0. 1 10 Days M/Mo=10 -2 -20 Fe-Kilonova, β=0. 1 r-process, β=0. 1 -15 • broader light curve • suppression of UV/O emission UV/O and shift to infrared bands 1041 1040 -10 Magnitude New simulations including lanthanides opacities show: Luminosity(ergs/s) 1042 Opacities: Fe r-process - 5 0 5 3 5 7 1 3 5 7 1 3 5 7 1 3 5 7 10390 2 4 6 8 10 12 14 Days Barnes & Kasen 2013, Ap. J, 775 Days 13

The Advanced VIRGO/LIGO Era - Growing emphasis on the search for the astrophysical counterparts of candidate gravitational wave (GW) event - From astrophysically triggered searches to searches triggered by GW candidate events. - Astrophysical counterparts required to confirm nature of GW events

Advanced GWdetector era observing scenario Position uncertainties with areas of tens to hundreds of sq. degrees Summary of plausible observing scenario LSC & Virgo collaboration a. LIGO/Virgo Range ar. Xiv: 1304. 0670 Rate Localization 18

GRB 970228: the 1 st X-ray and Optical afterglow • • Fast follow up with the Beppo. SAX-NFIs (8 hr) led to the discovery of a bright unknown Xray source. A second pointing 3 days after showed that source had faded. (Costa, et al. , 1997) • Accurate (~1 arcmin) X-ray position led to the identification of a fading optical source from ground based telescopes (Van Paradijs, et al. , 1997) (Pedichini et al 1997)

- High Energy Satellites: * Wide field monitors (e. g. Swift), limited sensitivity * X-ray optical design available (WFXT), but no approved program yet - Optical/NIR: large field of view instruments needed * Medium and Large telescopes have instruments < 1 deg^2 * Few very small automated large field telescopes (~100 deg^2, R <10 -12) (Tortora, Pi. Sky) * Dawn of “Time Domain Astronomy”: PTF (1. 2 m, 8 deg^2, R<21, 5 d), Pan. STa. RR (1. 8 m, 9 deg^2, R< 22, 1 month) * End of decade: LSST (8. 4 m^2, 10 deg^2, R~24, ¼ sky twice/night) - Radio: • VLA, LOFAR, SKA “Culture” of fast-response follow up observations: available especially in the SN and GRB communities.

Optical transient sky Kasliwal 2011, BASI, 39 Exploration of the optical transient sky at faint magnitudes and short timescale has started recently, but it is still unknown. . Optical contaminating transients: foreground - asteroids, M-dwarf flares, CVs, Galactic variable stars background - AGN, Supernovae For rate see Rau et al. 2009, PASP, 121 and for fast transient (0. 5 hr – 1 d) see Berger et al. 2013, Ap. J, 779 Transient X-ray and radio sky is less populated than the optical sky X-ray contaminating transients: tidal disruption events, AGN variability Ultra-luminous X-ray Source variability, background GRBs For rate in the Advanced LIGO/Virgo Horizon see Kanner et al. 2013, Ap. J, 774 Radio contaminating transients: Supernovae, AGN variability For rate see Mooley et al. 2013, Ap. J, 768 27

Other groups : PTF - Palomar Transient Factory 8 deg “The case of GRB 130702 A demonstrates for the first time that optical transients can be recovered from localization areas of ∼ 100 deg 2, reaching a crucial milestone on the road to Advanced LIGO. ” Detection limit: R ~ 20. 5 Singer et al. 2013: “We report the discovery of the optical afterglow of the γ-ray burst (GRB) 130702 A, identified upon searching 71 deg 2 surrounding the Fermi Gamma-ray Burst Monitor (GBM) localization. ”

INAF (Istituto Nazionale di Astrofisica) decided to participate in the EM follow-up program as an Institution by providing Italian observational resources and the expertise in time domain astronomy

STEPS for an efficient EM-follow up Wide-field telescope FOV >1 sq. degree • Reference Images • Observational strategy • Send data to Image Analysis Server VST Image Analysis Server “Fast” and “Smart” software to select a sample of candidate counterparts Candidate characterization VLT LBT The EM Counterpart of GW! • Image Analysis is performed by running specific pipelines. • The human intervention is not yet negligible. • Spectra vs templates • Light Curves • Multi-wavelength analysis (Near-IR, Radio, hugh energy from space, ASTRI, CTA)

INAF- project: Gravitational Astrophysics Advisory Board P. I. : E. Brocato Working Groups WP 1 WP 2 WP 3 WP 4 WP 5 • GW astronomy • Contact with LIGO / Virgo Collaboration • Search for EM candidates • Photometric software • Surveys, Ref. Images • Characterization • Spectroscopy • Light Curves • Multiwavelegth observations • To. O proposals • Relationship EU partners • Space • Time Domain Astronomy • VLT • NTT • ESO telescopes • Swift • XMM • Chandra • Fermi • INTEGRAL • GW physical information • EM Observational strategies • Simulations • VST • CITE • Asiago • TORTORA • Sicily (tbd) • LBT • NOT / TNG (? ) • REM • AZT-24 (NIR) • SRT (Radio)

INAF: WIDE-FOV telescopes to cover the GW error box South America VST - 2. 6 m VLT Survey ESO telescope corrected FOV 1 deg x 1 deg, pixel scale of 0. 21”/pixel 1 hour to cover a sky area of 40 sq. deg. in r’ band reaching a magnitude of about 23 in 2016 the INAF-Guaranteed Time Observation 20% of the total observing VST time Public Surveys: Reference Images available REM (Rapid Eye Mount): 60 cm diameter fast robotic telescope TORTORA camera (Telescopio Ottimizzato per la TORTORA camera Ricerca dei Transienti Ottici RApidi) FOV 24°x 32°, time resolution 0. 1 s, B-limiting magnitude 11 two cameras can observe simultaneously in optical and NIR (J, H e K), FOV 10 x 10 arcmin

INAF: WIDE-FOV telescopes to cover the GW error box Europe “Campo Imperatore Transient Experiment”: Experiment 60 cm Schmidt telescope with a 2 sq. deg. FOV up to V ~21 mag (project to extend to 6 sq. degree) near-IR telescope, AZT-24 Fo. V of 4. 4’x 4. 4’ for characterization AZT-24 Funds to realize a 1 m Telescope (FOV 8 sq. deg) in Sicily + SMALLER FOV telescopes like Asiago, Loiano, IRAIT can help during the search and/or are useful for the characterization

INAF: Characterization of the EM counterparts candidates North America Large Binocular Telescope (Arizona) excellent for characterization, INAF GTO+To. O (25 % INAF) § two 8. 4 meter primary mirrors . § collecting area equivalent to an 11. 8 -meter circular aperture § Optical/IR spectrographs § Large Binocular Camera, FOV 23'x 23' , sampling of 0. 23”/pixel South America Very Large Telescope (VLT, ESO) • four unit telescopes with main mirrors of 8. 2 m diameter • very useful X-shooter spectrograph covering a very wide range of wavelengths [UV to near infrared] simultaneously INAF intends to coordinate collaborative To. O proposal involving other European groups working in the field

INAF: Characterization of the EM counterparts candidates Canarie TNG (Telescopio Nazionale Galileo) 3. 58 m optical/infrared telescope currently optimally equipped for “exoplanet search” its position could be crucial for the EM-follow up, few possibilities to set up instruments for this program NOT (Nordic Optical Telescope 2. 5 m) (+ Xshooter? ) good candidate for GW follow-up, thanks to its good optics and versatile instruments: e. g. ALFOSC (Andalucia Faint Object Spectrograph and Camera) GTO (fraction) + proposal for To. O

INAF: Radio facilities INAF radio antennas: Medicina (30 m parabolic antenna) Noto (32 m parabolic antenna) Sardinia Radio Telescope (64 m) SMALL FOV characterization INAF: Space high-energy facilities From space, INAF can guarantee access - through submission of regular or DDT proposal starting from coordinated initiatives of the INAF scientists - to Swift, XMM, Chandra, Fermi, INTEGRAL. INAF: Archival search LBT + VST image archives ASDC Archive of space missions + ESO data archive

INAF- project: Gravitational Astrophysics Ø Large Fo. V (1 x 1 d)+ mag limits (< 23 m) + High resol. (0. 2 p/”) Ø Characterization: up to 8 m class telescopes Ø Site: southern and northern hemisphere Ø Wide wavelength coverage: ground based facilities from optical to radio + high-energy space facilities Ø Know-how: Time Domain Astronomy, Observational Strategy, Image analysis, Accurate Photometry in crowded fields, GRB astronomy, Data Interpretation, Theoretical models u Collaboration with Virgo teams is crucial To remain in touch: https: //sites. google. com/site/followupgw/home

VESF – Virgo EGO Science Forum The scope of VESF is promoting the physics of gravitational waves, and the collaborations among groups in different countries The Forum is intended to be open to scientists in the field of astrophysics, astroparticle, general relativity, gravitation etc, that may be interested in the data expected from Virgo and its future upgrades. VESF presently comprises: 34 groups, 182 members from Virgo, 149 non-Virgo belonging to European universities, laboratories and astronomical observatories.

VESF Executive Board. The executive board is presently composed by - the EGO director (Federico Ferrini) - the Virgo spokesperson (Jean-Ives Vinet) and four members elected by the VESF Council for a period of two years, to represent the following research areas - General Relativity (Nikolaos Stergioulas) Theoretical Astrophysics and Cosmology (Toni Font) Observational Astrophysics (Andrea Possenti) Experimentation in fields related to GW detection not participating to Virgo (Guglielmo Tino) The EB elected the VESF Coordinator, choosing in a pool of candidates proposed by the VESF community (Luigi Stella) Jan 2014 VESF EB Meeting: proposal of revised VESF Charter sent to VSC