Why has so little attention been devoted to oscillating late-time afterglow evolution of NGC 4993/GRB170817A/AT2017gfo?

Why has so little attention been devoted to oscillating late-time afterglow evolution of NGC 4993/GRB170817A/AT2017gfo?

https://www.aanda.org/articles/aa/pdf/2018/05/aa32664-18.pdf

The optical emission of GW170817/GRB170817A/SSS17a/AT 2017gfo was visible within 11 hours of the putative LIGO GW signal (near-IR identified first by Swope), 15.3 hours later in UV (Swift), X-rays after 9 days (Chandra), and radio emission at 16 days (Jansky VLA) https://dcc.ligo.org/public/0145/P1700294/007/ApJL-MMAP-171017.pdf.

Recent papers relating directly to GW170817 multiwavelength observations are few, but many new debates have emerged upon presentation by various teams of mutually-inconsistent afterglow, remnant, and mass scaling observations and models.All imply, collectively, a tacit doubt may prevail; the fact of inevitable customary and rightful debate is downplayed in official LIGO-Virgo channels. Where debates over interpretations exist, such are limited to those arguments that do not openly reject the association between GW170817, NGC 4993, and GRB170817A. Contradictions often stem from use of progressive hypothesis revision while committed to an effective systematic type I error resulting from poor protocols, variables, heuristic. 

The most recent available Chandra reports for GW170817 putative source (December 2020) affirm positive, > 5 sigma observation of increasing X-rays of AT2017gfo/GRB170817A at  t=1209-1213 days (~3.3 yrs) since August 17, 2017. 

https://sites.google.com/u.northwestern.edu/synchrotron-emission-from-gw17/home

Increasing X-ray flux after 3.3 years refutes off-axis jet afterglow model and structured jet model - "KN afterglow" proposed in Hajela et al. 2021. 

GCN CIRCULAR 29055https://ui.adsabs.harvard.edu/abs/2020GCN.29055....1H/abstract…GCN CIRCULAR 29041https://ui.adsabs.harvard.edu/abs/2020GCN.29041....1H/abstract…GCN CIRCULAR 29038 https://ui.adsabs.harvard.edu/abs/2020GCN.29038....1T/abstract…GCN CIRCULAR 29019 https://ui.adsabs.harvard.edu/abs/2020GCN.29019....1H/abstract…

If  LIGO signals are to be salvaged despite any non-cosmological origin, we must address evasive practices that are still being committed by the LIGO-Virgo collaboration. Obfuscating analysis and restricting discourse to ignore strong foreground correlations that would interfere with this epistemological salvaging will most likely yield strictly diminishing returns, as it were. The prospect of novel physics in terrestrial-solar interaction with cosmological-scale gravitational waves will be ignored as long as the same observations can be so damaging to desired outcomes from hypothesis testing. 

For LIGO-Virgo, testing of single favored a priori models against disliked alternatives protects confirmation bias, with differentiation of signal and noise left in a perpetually inchoate state, mere "glitches" bound to discrete categories with arbitrary/aesthetic/morphological distinctions assigned by amateurs. LIGO remains dedicated, necessarily, closely to its near-degenerate parameters and noise-contaminated signals; use of LIGO data for fundamental physics has been very limited and no revisions have been commanded to standard cosmological indices/values. For LIGO, <50% luminosity distance error is considered moderate. Objectivity is replaced plank by plank until no traces of original data remain unmodified (or supplanted by integrated Bayesian probabilities, in the worst permitted case). 

Prior observations of AT2017gfo:

GCN CIRCULAR 27414, Chandra observations of GW170817 at 2.5 years since merger [Hajela et al 2020] gcn.gsfc.nasa.gov/gcn3/27414.gcn3 

Afterglow models must be revised/discarded: "X-ray emission[...]at the location of #GW170817 with a significance of ~5 sigma[... . ...]using a simple power-law spectral model with photon index Gamma ~ 1.6[... .] Future Chandra observations [...] December 2020[... .]

Observation at 584.1 days (Fong et al. 2019, with no decrease in afterglow, very unstable afterglow, no simultaneous model observations in any wavelength utilized), we investigate how AT2017gfo is related to GW170817 and GRB170817A:

"...we find that the afterglow in most epochs is systematically brighter than previously reported, with differences of ∆m ≈ −0.1−1 mag between published values and the values presented... ."
https://arxiv.org/pdf/1908.08046.pdf

 

https://twitter.com/Fulguritics/status/1265461984423579650
Another retroductive pseudo-confidence boost for #GW170817: "#GRB170817A as a Refreshed Shock Afterglow viewed off-axis" Lamb et al. 2020https://arxiv.org/pdf/2005.12426.pdf…; Total degeneracy in all light curves mentioned ONCE, citing Nakar and Piran 2020 https://arxiv.org/pdf/2005.01754.pdf… who found 16° angle of inclination only determinable model-free value; H0 cannot be calculated from #GW170817. 

Preliminary analysis of systematic/metric degeneracy (original data reported in "GRB 170817A as a Refreshed Shock Afterglow viewed off-axis" [Lamb et al. 2020])

arxiv.org/pdf/2005.12426.pdf

List of papers of notable significance in the analysis and characterization of the GW170817/GRB170817A event and follow-up

Afterglow constraints on the viewing angle of binary neutron star mergers and determination of the Hubble constant [Nakar and Piran 2020]

 https://arxiv.org/pdf/2005.01754.pdf

GRB 170817A as a Refreshed Shock Afterglow viewed off-axis [Lamb et al. 2020]

arxiv.org/pdf/2005.12426.pdf

The Optical Afterglow of GW170817: An Off-axis Structured Jet and Deep Constraints on a Globular Cluster Origin [Fong et al. 2019] 

https://arxiv.org/pdf/1908.08046.pdf

The optical afterglow of GW170817 at one year post-merger 

[Lamb et al. 2018]
https://arxiv.org/pdf/1811.11491.pdf

A long-lived neutron star merger remnant in GW170817: constraints and clues from X-ray observations [Piro et al. 2018]

https://arxiv.org/pdf/1810.04664.pdf

Low frequency view OF GW 170817/GRB 170817A with the giant metrewave radio telescope

  [Resmi et al. 2018]

https://arxiv.org/pdf/1803.02768.pdf

Observational signatures of microlensing in gravitational waves at LIGO/Virgo frequencies 

[Diego et al. 2019]
https://arxiv.org/pdf/1903.04513.pdf

Reinterpreting Low Frequency LIGO/Virgo Events as Magnified Stellar-Mass Black Holes at Cosmological Distances [Broadhurst et al. 2019]
https://arxiv.org/pdf/1802.05273.pdf
In The optical afterglow of GW170817 at one year post-merger [Lamb et al. 2018], afterglow imaging and data processing have high uncertainties, with background brightness and resolution oscillating with AT2017gfo.AB mag is empirically brighter, but differential changes in luminosity and flux relative to wavelength are proving to be consistent with a kind of barberpole illusion due to systematic error, with models taking advantage of boundless nonstationarity in fitting. Masks over strong sources in images are at arbitrary, adjusted brightnesses, corrupting analysis from direct empirical normalization. Lamb et al 2018 claim that Piro et al 2018 observations of flattening/oscillating AT2017gfo post-merger flux and luminosity are probably based on spurious observations; Lamb et al. 2018 claims that flux and luminosity are differentially declining, but report increasing AB Mag (with increased compensatory error) after one year. So, their conclusions are possibly unreliable and seemingly contradict the data. A disturbing trend continues from such desperate LIGO efforts as the Nielsen et al. 2018 reanalysis of GW150914 L1-H1 cross-correlations ([1811.04071] Investigating the noise residuals around the gravitational wave event GW150914 - see https://fulguritics.blogspot.com/2018/12/extended-criticisms-of-three-very.html) in sloppy positioning of plot legends, with dashed ring features centered poorly that cover critical information and prevent ready analysis of publication data - virtually obscuring target data and reducing visibility of coordinate deviation relative to foreground/background. Ambiguities and conflicts are rendered less obvious (as these occur exactly where information may be desired to be misleading) , and one wonder if this in intentional.

Tables and imaging from The optical afterglow of GW170817 at one year post-merger [Lamb et al. 2018]:

AB mag increases over year - all prior models challenged; model-based analysis of measurements contradicts this trends, preferring strong prior expectation for inevitable afterglow decline given synchronized mutual error from multiple wavelength studies. Decline in luminosity is smaller than error, but error increases over time, which has become a proxy for decrement, rather than oscillation, foreground variation/instrumental error (with unknown introduction period and level), or even that different objects are actually being observed at different times
unmodified:
All images processed uniformly to reveal nonstationary, masks, artifacts, and incompatible resolution between epochs/exposures, in which subtle effects combining luminous covariation of objects, scintillation, scattering/polarization/absorption by dust and gas, and extinction may be considered:

Hubble images of AT2017gfo (Lamb et al. 2018), processed to isolate error, identify imbalanced background contrast, and locate feature boundaries and masks to assess nonstationary error. Most importantly, foreground identity for AT2017gfo, uncorrelated with GW170817/GRB170817A, is still to be excluded, as NGC 4993 was identified under conditions of extreme error and degenerate parameter estimation from inductive feedback from observatories searching a 28 deg2 sky area/41 Mpc+/-20 Mpc probability space. The loss of pixel information after 170.5d is correlated to loss of background information, which indicates that no decline in luminosity can be assessed from these data as presented, consistent with Piro et al. 2018.

 tables and imaging from

A long-lived neutron star merger remnant in GW170817: constraints and clues from X-ray observations [Piro et al. 2018]:

Flatness in AB mag and oscillation in flux are observed, not decline in both as expected/necessary.

Nonstationarity in imaging (contrast weighted inconsistently between images/data due to different data resolution/foreground differences), and apparent X-ray source simultaneous brightness/coordinate variation:

[the Chandra X-ray observatory had been forced into safe mode due to a gyroscope failure, a week following the 2018 temporary deactivation of the Hubble telescope Another NASA space telescope shuts down in orbit, reported to be operational again as of 11/2018]

It came to my attention that LIGO had requested their designation retroactively-attached to an event alert despite that it being a Fermi GBM trigger:

https://gcn.gsfc.nasa.gov/gcn/gcn3/21505.gcn3

TITLE: GCN CIRCULAR

NUMBER:  21505
SUBJECT: LIGO/Virgo G298048: Fermi GBM trigger 524666471/170817529: LIGO/Virgo Identification of a possible  gravitational-wave counterpart
DATE:    17/08/17 13:21:42 GMT
FROM:    Reed Clasey Essick at MIT  <ressick@mit.edu>
[... . ...]
[GCN OPS NOTE(17aug17): Per author's request, the LIGO/VIRGO ID 

was added to the beginning of the Subject-line.]]

An issue one can raise regarding confidence in prior survey data from the NGC 4993 sky area is that these surveys do yield significant evidence for a faint GW170817 precursor in all available images, and at a relative spatial scale too large to be an NGC 4993 object (especially neutron stars and their domain of influence). Without being able to account for possible significant relative motion with respect to foreground and background contamination in images from NGC 4993 AGN, SSS astronomers involved in the localization of the putative GW170817 compact binary source have possibly violated many robust analytical protocols. There is a strong variable X-ray source captured in NGC 4993 imaging by Chandra and XMM-Newton that has not been emphasized for its similarity to the possibly variable x-ray profile of SSS17a. Authors are vague and appeal to broad consistency with uncorrelated parameters, but never admit that well-behaved multiparametric correlations can be obtained:

"We find no clear evidence for a prior outburst at the location of SSS17a between 2004 and 2016 to V-mag limits varying from 18 to 19 (depending on observing conditions and telescope). However, since the data during this period is relatively sparse, we are unable rule out prior outbursts with timescales as short as the SSS17a event itself."
http://www.astronomerstelegram.org/?read=10856                                                              "We also examine the three previously-detected X-ray sources CXOU J130948, CXOU 130946, and the host galaxy NGC 4993. The fluxes of CXOU 130946 and the host-galaxy NGC 4993 are consistent with our previous deep Chandra observations, while CXOU J130948 appears to be variable in X-rays (Margutti et al. 2017; Haggard et al. 2017)." http://www.astronomerstelegram.org/?read=11041

Processed images of NGC 4993 sky area (most visible luminous features in these images, one must be reminded, are located in the local galactic foreground):
[original]

[filtered]

 

Linear time series plots of light curve values and scatterplots from Chandra and XMM-Newton for X-ray flux/luminosity and 90% CI of SSS17a/GW170817 from Burnichon et al.2018 and Haggard et al.2018, assuming luminosity distance of 42.5 Mpc [Flux, 10^-14 erg/s/cm^2, Luminosity,10^38 erg/s]:

Rueda et al. 2018 addresses physical association between GW170817/GRB170817A and AT 2017gfo; many post-merger kilonova models are examined given updated (post-August, 2018 "blackout") late-time evolution of afterglow; white dwarf-involved mergers are considered, inconsistent with LIGO claims:
GRB 170817A-GW170817-AT 2017gfo and the observations of NS-NS, NS-WD and WD-WD mergers

Compilation of light curve values from Chandra and XMM-Newton for X-ray flux/luminosity and 90% CI of SSS17a/GW170817 from Burnichon et al.2018 and  Haggard et al.2018, assuming luminosity distance of 42.5 Mpc:

Days   from                                           GW170817	Flux, 10^-14        erg/s/cm^2	+	-	Luminosity,10^38 erg/s	+	-	dFlux	dLuminosity
2.3	<0.13	N/A	N/A	<3.2	N/A	N/A	<0.13	<3.2
9.2	0.34	0.15	0.11	9.2	4.6	4.9	0.21	6
15.6	0.36	0.17	0.12	10.8	5.2	2.6	0.02	1.6
109.2	1.88	0.38	0.28	51	8.2	9.3	1.52	40.2
135	1.9	1.7	0.9	52	24	19	0.02	1
159.7	2.06	0.34	0.3	55.3	12.9	8.9	0.16	3.3
162	1.7	0.6	0.5	46	15	15	-0.36	-9.3
260	1.09	0.24	0.2	29.6	7.1	6.5	-0.61	-16.4
358.6	0.63	0.38	0.21	17	11	5	-0.46	-12.6

The best and most direct information available on GW170817 post-merger does not reside in peer-reviewed publication, but in direct information disclosure in a 9th August update on The Astronomer's Telegram:

“Below, we provide a light curve table of all currently-available Chandra and XMM-Newton observations of GW170817. We note that all flux and luminosity measurements are from our own independent analysis of the data (reported here and in Nynka et al., 2018), except for the Chandra observations at 2.3 days, which are rescaled from Margutti et al. (2017).
Days, Telescope, Flux*, Luminosity**
2.3, Chandra, <0.13, <3.2
9.2, Chandra, 0.34 (+0.15/-0.11), 9.2 (+4.6/-4.9)
15.6, Chandra, 0.36 (+0.17/-0.12), 10.8 (+5.2/-2.6)
109.2, Chandra, 1.88 (+0.38/-0.28), 51.0 (+8.2/-9.3)
135, XMM-Newton, 1.9 (+1.7/-0.9), 52.0 (+24/-19)
159.7, Chandra, 2.06 (+0.34/-0.30), 55.3 (+12.9/-8.9)
162, XMM-Newton, 1.7 (+0.6/-0.5), 46 (+15/-15)
260.0, Chandra, 1.09 (+0.24/-0.20), 29.6 (+7.1/-6.5)
*Flux units: [10^-14 erg/s/cm^2], 0.3 - 8 keV absorbed flux
**Luminosity units: [10^38 erg/s], 0.3 - 10 keV unabsorbed luminosity, assuming DL = 42.5 Mpc
(all uncertainties are 90% c.l.)”

and four days later in The Astronomer's Telegram:

“We report new Chandra X-ray observations of neutron star merger GW170817 at 358.6 days post-merger, which now reveals fading at a t^-1.6 rate.Chandra obtained a 67.16 ks observation of GW170817 (obsID: 21371, PI: Troja) on 10 August 2018, at 358.6 days post-merger. GW170817 is still clearly detected, and we measure a 0.5-8 keV count rate of 4.9 (+0.9/-0.9) cts/s. We extract and fit the X-ray spectrum assuming an absorbed power-law spectral model, with fixed NH = 7.5e20 cm^-2. We measure an absorbed flux of f(0.3-8 keV) = 6.3 (+3.8/-2.1) x10^-15 erg/s/cm^2 (90% c.l.) and photon index of Gamma = 1.6 (+1.3/-0.9), which corresponds to an unabsorbed luminosity of L(0.3-10 keV) = 1.7 (+1.1/-0.5) x10^39 erg/s assuming a luminosity distance of 42.5 Mpc.The previous Chandra observation at 260.0 days showed an absorbed flux of f(0.3-8 keV) = 1.09 (+0.24/-0.20) x10^-14 erg/s/cm^2 (Nynka et al. 2018). A power-law fit of this previous 260.0 day flux to the new 358.6 day flux reveals fading at a t^-1.6 rate. This is steeper than the t^-1.3 fading observed between 159.7 and 260.0 days post-merger, and thus the X-ray afterglow light curve is now fading more rapidly.”

One may contest the unspecified exact process used by Daryl Haggard et al. to fit their data to a power law curve, which indicated that luminosity is decreasing at an increased rate. Absolute data do not show that luminosity is decreasing at an increased rate, but  error statistics are utilized prima facie. As the rate of decrease of luminosity is actually decreasing, not increasing, may absolute magnitude now be rising >100 days since last Chandra observation of the X-ray object AT2017gfo? In absence of any known observations since early August, 2018, we cannot come to any conclusions. Chandra/XMM-Newton X-ray flux and luminosity values are naively well-modeled with a 3rd degree polynomial at very high R^2 (>0.98); it can be extrapolated that rising flux|luminosity may now be observed, an inconvenience complicated by the coincidental deactivation [reactivated as of 11/2018] of Chandra only eight weeks after the last Chandra observation of AT2017gfo was reported in AT. Yet again, we may be prudent to consider that SSS17a/GW170817 may be brightening again in X-ray, which could further signal that a kind of kilonova imposter or foreground X-ray variable star, completely uncorrelated to GW170817/GRB170817A arrival. 

[LIGO-Virgo GW transient arrival from 150101 and luminosity distances of all seven GW transients, with LIGO standard bounds; notice how reliable distance-dependent calculations may become unreliable at very few inductive steps; a study on excess LIGO event parameter correlations associated with unacknowledged observational and orbital bias is available here: https://fulguritics.blogspot.com/2018/06/roger-penrose-penrose-2017-may-be.html]

Information on foreground effects during GW170817 trigger: https://fulguritics.blogspot.com/2018/06/gw170817-occurs-at-green-bar.html
Information on foreground effects during GW150814: https://fulguritics.blogspot.com/2018/06/progress-on-ligo-event-analysis-here.html
Calculated time lags and other crucial properties of the GW150914 event from terrestrial source[s]: https://fulguritics.blogspot.com/2018/06/blog-post.html
Plotted ground magnetometer data for coincident anomalous geomagnetic behavior in North America surrounding LIGO stations during GW150914: https://fulguritics.blogspot.com/2018/06/httpswww.html

As learnt from comparing information from 13th August 2018 on The Astronomer's Telegram to various conflicting observations and peer-reviewed interpretations of the post-merger emission, odd X-ray luminosity brightening with unpredictable error oscillation are captured implicitly by the provisional light curve (see plots). Possible non-monotonicity can remain unobserved given choice for arbitrary observation intervals and days-long photon collection yielding means from summation values.

What are being described as among the largest neutron stars are now being claimed to have produced the smallest known black hole with weakest EM transients (despite any off-axis modeling); expectations are perhaps too open with respect to closed theory of the polemical LIGO variety, however true such assumptions. Possibly the strangest feature of the post-merger luminous time domain behavior of the putative GW170817 source is precisely in time signatures of observations: some attempts to observe the source have failed on fractionally-incompatible days or for weeks or months at a time, notwithstanding occlusion by the sun. Very few observations with wide wavelength coverage exist. Dusts, lensing, and plasma interfering with photon path will modulate Earth orbit-determined observation window time series. Key almost-invariant light curve envelope period lengths for certain long-period X-ray variable stars seem to accompany the few successful, information-laden observations of the GW170817 source believed to be in NGC 4993 (and the particular luminosity distance adaptively-calculated by LIGO at 40 ^+8_-17 Mpc, which a posteriori scales analytical parameters). Considering there is serious discussion about possible variable star activity perhaps being conflated with a GW170817 source (Texas Sharpshooter Fallacy), and as kilonova evolution models are unexpectedly failing the more we inject expectation into the empirical GW170817 portrait - its outcome seemingly hanging from a cliff by a finger at the margins of residual distributions - we should probably stop pretending to be convinced that we even understand what happened on August 17, 2017 UTC. It is also important to note a failure to detect expected neutrino emission, explained away by the supposed off-axis orientation of the initial relativistic jet responsible for the GRB170817A trigger: No neutrino emission from a binary neutron star merger.