Chronicle of a (neutron star) death foretweeted


At 12:41:06.47 UT on 17 August 2017, the Fermi Gamma-Ray Burst Monitor triggered and located GRB 170817A (trigger 524666471 / 170817529). The on-ground calculated location, using the GBM trigger data, is RA = 176.8, DEC = -39.8 (J2000 degrees, equivalent to 12 h 47 m, -39 d 48') with an uncertainty of 11.6 degrees
Andreas von Kienlin at MPE (Max Planck Institute for Extraterrestrial physics)


Run ID: 198.D-2010(A)*
DATE = '2017-08-17T23:42:50' / Date this file was written
TELESCOP= 'VISTA' / ESO Telescope Name
INSTRUME= 'VIRCAM' / Instrument used.
OBJECT = 'Str02' / Original target.
RA = 193.146379 / 12:52:35.1 RA (J2000) pointing (deg)
DEC = -15.44247 / -15:26:32.8 DEC (J2000) pointing (deg)
... 
DATE = '2017-08-18T00:00:21' / Date this file was written RA = 197.047354 / 13:08:11.3 RA (J2000) pointing (deg)
DEC = -23.78829 / -23:47:17.8 DEC (J2000) pointing (deg)
DATE-OBS= '2017-08-18T00:00:23.2486' / Observing date
...
HIERARCH ESO OBS NAME = 'TOO_GW198_template_G298048C_2_1_1' / OB name
HIERARCH ESO OBS PROG ID = '198.D-2010(A)' / ESO program identification
PI: Tanvir , Nial
Abstract: 
The first direct detection of gravitational waves (GW), from a coalescing binary black hole system, was made by Advanced LIGO (aLIGO) in Sept 2015. Operation of the aLIGO/aVIRGO network is expected to lead to regular discoveries of merging compact binaries (i.e., comprising neutron stars (NS) and/or black holes (BH)) in the coming years. Recent evidence for late-time near-IR emission from a short-duration GRB, indicative of an r-process ``kilonova" (KN; powered by radioactive decay of NS material ejected during the merger) both confirms that SGRBs are also created in NS-NS/NS-BH mergers, and provides a new, {\em unbeamed and characteristic} EM signature of these GW-bright events. We propose a VISTA campaign to search for KN emission in the nIR (line-blanketing is predicted to make them optically faint) accompanying GW detections during P98--P103. Coupled with further spectroscopic and imaging followup, this will greatly increase the science return (redshifts, host environment etc.) of the early GW detections. It will also open the door to quantifying the contribution of compact binary mergers to global $r$-process nucleosynthesis.
European South Observatory Archive 


New LIGO. Source with optical counterpart. Blow your sox off!
J Craig Wheeler on Twitter 18 August


Proposal 14804 - Rapid Target of Opportunity (ToO) observations of the first gravitational wave counterparts 
Cycle: 24, Target: GRB170817A  Configuration: WFC3/IR  Orbits: 4 
Last orbit planner run 18-Aug-2017 14:05:32.0 to 14:05:36.0 
ABSTRACT: We propose a series of disruptive ToO observations of the first electromagnetic counterparts to gravitational wave sources. These observations will track the likely rapidly fading counterparts to levels a factor 10 fainter than possible from the ground. They will determine the spectral and temporal evolution, evaluate their power sources, ascertain their contribution to the production of heavy elements in the Universe, pinpoint them on their host galaxies and provide information to hone further searches. In concert with already award late time (>3 week turnaround) observations these observations will provide a unique and powerful view of a newly discovered, but long awaited class of astronomical object.


Sequence number : 401823 Obs ID: 18955 Target: SGRB170817A Start: 2017-08-19 17:09:01
Title: Tracking the Evolution of an X-ray Counterpart to a Gravitational Wave Event

Abstract: The premier candidates for the emission of gravitational waves (GW) are compact object mergers. By 2017, the typical localization uncertainties with Advanced LIGO-Virgo will be 200 sq. deg. The detection of a counterpart at electromagnetic wavelengths will leverage the GW signal by providing a sub-arcsecond position, redshift, energy, and host galaxy. While a blind search in the X-rays of the full GW localization is not feasible, we have an ongoing Target of opportunity (TOO) program with the wide-field imager DECam to identify the optical 'kilonova' counterparts to GW signals. Here, we propose to monitor the 100-day evolution of the X-ray counterpart to a GW event by following a single candidate identified by DECam. The successful detection of the X-ray counterpart will be a milestone in the era of GW discovery.


Proposal 15382 - UV Spectroscopy of GRB170817A
Cycle: 25, Target: GRB170817A Configuration: STIS/CCD STIS/NUV-MAMA
Orbits: 1 Last orbit planner run 22-Aug-2017 12:00:38.0
ABSTRACT: GRB170817A is the most nearby short GRB ever discovered. We detected an optical counterpart using DECam and propose to obtain a UV spectrum using STIS.


I am looking at the Star BNS [Binary Neutron Star]-MERGER with Space Telescope Imaging Spectrograph for on Tue 22 August 2017 22:38:01-4:00
 What is @HubbleTelescope looking at?


Proposal 15346 - Verifying a candidate counterpart to gravitational waves
Cycle: 24, Target: NGC4993 OT Configuration: WFC3/UVIS Orbits: 2
Last orbit planner run 22-Aug-2017 from 16:17:03 to 16:17:04
Target: GROWTH-EMGW Configuration: WFC3/IR WFC3/UVIS Orbits: 10
Last orbit planner run 22-Aug-2017 from 16:17:05 to 16:17:07
ABSTRACT: With advances in sensitivity of gravitational wave interferometers, the direct detection of neutron star mergers should be imminent. Identification of an electromagnetic counterpart would enable a wealth of astrophysics and answer the long-standing question of whether neutron star mergers are the missing cosmic mines of heavy elements synthesized by the r-process. We will be searching for a fast-fading optical counterpart with the new Zwicky Transient Facility at Palomar Observatory. Here, we propose to use HST/WFC3 to look for infrared emission from a single, most-promising candidate optical counterpart. The infrared emission would serve as a direct diagnostic of the radioactive decay of heavy elements.


Proposal 14850 - Identify the signature of neutron star mergers through rapid Chandra/Hubble observations of a short GRB (see also proposals: 15346, 15382)
Cycle: 24, Target: SHORT-GRB Configuration: WFC3/IR/UVIS Orbits: 4
Last orbit planner run 23-Aug-2017 from 14:10:12.0 to 14:10:16.0
ABSTRACT: The afterglow of some short GRBs displays a late-time rebrightening, visible a few days after the gamma-ray burst. Recent HST observations provided tantalizing evidence that such late-time bump could be explained as the emergence of the underlying kilonova emission. This would represent the incontrovertible signature of a neutron star merger, and the first direct link between short GRBs and their progenitors. Here we ask for a rapid and deep Chandra/HST follow-up observation of a short duration GRB in order to detect the expected kilonova bump, and to constrain the origin of the observed emission. Multi-band observations, and in particular X-rays, are critical to pin down the nature of the observed rebrightening, and to distinguish it from the standard afterglow emission.  

... God may be a detector commissioner. At the start of [scientific run] O1, we didn’t have the hardware injection systems operational, but GW150914 showed that things were working properly. Now, with a third detector on-line, GW170814 shows that the network is functioning properly. Astrophysical injections are definitely the best way to confirm things are working!
CHRISTOPHER BERRY (Gravitational-wave astronomer)




What I just heard is that there are rumors of another event, not two black holes, but a black hole and a neutron star, and that for that event there was EM confirmation. Supposedly observed a few days after {GW170814}. No comment as yet about it from either LIGO or VIRGO.
Jeff M's comment on the blog Not Even Wrong
//Update October 12, 2017
ESO will hold a press conference on 16 October 2017 at 16:00 CEST {UTC+2}, at its Headquarters in Garching, Germany, to present groundbreaking observations of an astronomical phenomenon that has never been witnessed before.
The event will be introduced from ESO’s Paranal Observatory in Chile by the Director General, Xavier Barcons, and will feature talks by representatives of many research groups around Europe.

The gathering will begin with an overview of new findings from LIGO, Virgo and partners that span the globe, followed by details from telescopes that work with the LIGO and Virgo collaborations to study extreme events in the cosmos.

 // update october 16, 2017
On August 17, 2017 at 12∶41:04 UTC the Advanced LIGO and Advanced Virgo gravitational-wave detectors made their first observation of a binary neutron star inspiral. The signal, GW170817, was detected with a combined signal-to-noise ratio of 32.4 and a false-alarm-rate estimate of less than one per 8.0 × 10^4 years. We infer the component masses of the binary to be between 0.86 and 2.26 M⊙, in agreement with masses of known neutron stars. Restricting the component spins to the range inferred in binary neutron stars, we find the component masses to be in the range 1.17–1.60 M⊙, with the total mass of the system 2.74+0.04 −0.01M⊙. The source was localized within a sky region of 28 deg^2 (90% probability) and had a luminosity distance of 40+8 −14 Mpc, the closest and most precisely localized gravitational-wave signal yet. The association with the γ-ray burst GRB 170817A, detected by Fermi-GBM 1.7 s after the coalescence, corroborates the hypothesis of a neutron star merger and provides the first direct evidence of a link between these mergers and short γ-ray bursts. Subsequent identification of transient counterparts across the electromagnetic spectrum in the same location further supports the interpretation of this event as a neutron star merger. This unprecedented joint gravitational and electromagnetic observation provides insight into astrophysics, dense matter, gravitation, and cosmology

LIGO Scientific Collaboration and Virgo Collaboration
(Received 26 September 2017; revised manuscript received 2 October 2017; published 16 October 2017)

???
October Monday 16, 2017 9:30-10:15 {16:30 UTC+2} Baton Rouge Louisiana


Animation showing a simulated merger of a black hole and neutron star. (Credit: Bryant Garcia)
//* added on October 8 2017



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