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IDEA: A methodology paper about issues on source reconstruction
## First comments

Reading the old version, these are some comments: ## Past articles/Presentation/Poster

## State of the art

Reed paper presents results for 2015HL and 2016HLV, link at DCC. This paper should presents results from 3-fold network to 5-fold network, adding analysis using Invariant Topology detectors.
Last results on source reconstruction are in this wiki page. In particular: ## Results

I made some simulations of SG for various Q for LHV network. Results report median value of erA[0] over each single sky pixel (Healpix=4) and construct Lars Histogram.
Results show a dependency on frequency according to the sensitivity curve as in the figure:

## Comments and other proposal

According to the results, the following comes out: **Next proposal:**
Consider a methodological paper where studying in details the results explaining the possible causes, like explained in the previous bullets. Some starting point: ## Notes from LVC meeting in Pasadena

**Tentative title:**

Low-latency localization of sources of transient Gravitational Waves with generic waveforms

Assume that a low-latency GW detection is triggering a low latency GW follow-up for estimation purposes

- Check the
**earth coordinates**of KAGRA and LIGO/India

Last paper should be Phys. Rew. D 90, 024053 (2014) - Check if the
**sensitivity curves**have changed

The same paper gives the same curves we are already using (as it seems comparing the figures) - Remind the contributions of main effects on source estimation:
**Triangulation**-> Paper puts comparison with 3ifo Wen&Chen formula -> Put results from Feirhust paper?**Antenna pattern**-> Puts results using a small earth radius? - Analysis probably should be re-done with an appropriate
**cWB svn version**and configuration parameters: establish which - Decide which
**waveform**to use

- Stephen Fairhurst 2009
*New J. Phys.***11**123006 - L Wen
*et al*2008*J. Phys.: Conf. Ser.***122**012038 - Stephen Fairhurst 2011
*Class. Quantum Grav.***28**105021 - Klimenko et al, Phys. Rev. D
**83**, 102001 - Amaldi poster (DCC ligo)

- The comparison of
**un-modeled search (row 22)**with respect to a previous version link shows little difference, some better, other worse, but not so important. Improvements with respect to 1G still remains. - Some not understood aspects remains, in particular on
**P search (row 21).**This search performs a circular constraint adding a transformation on the pixel composing the cluster. In particular this transformation make a projection of the pixels likelihood according to the mean values of all composing the cluster. For an example see the link under the title "G & MASK". It is not still clear why the circular polarization waveform has worse results while linear polarization ones are better.

L1H1V1 | Median of erA[0] | 90 Percentile of erA[0] |
---|---|---|

Triangulation Error from Fairhust paper | ||

SGQ100 SGQ45 SGQ30 SGQ15 SGQ9 SGQ6 SGQ3 |
||

Q behaviour | ||

Linear Sine Gaussian, changing of Q | ||

SGQ100 SGQ45 SGQ30 SGQ15 SGQ9 SGQ6 SGQ3 |
||

Q behaviour | ||

SGQ9 Sample rate and Sky grid limitations | ||

SGQ9 SGQ9_upTDF SGQ9_Healpix8 SGQ9_Healpix_upTDF Benchmark (h) SGQ9 : 0.19 upDTF: 0.26 Healpix: 0.32 Healpix_upTDF: 0.38 |
||

Linear Sine Gaussian, Search R, S, P | ||

SGQ100 R SGQ100_S SGQ100_P SGQ9_R SGQ9_S SGQ9_P SGQ3_R SGQ3_S SGQ3_P SGCQ3_WNB |
||

Elliptical waveform SGEQ9 Search R | ||

e=1.0 (C) e=0.6 e=0.4 e=0.3 e=0.2 e=0.1 e=0.0 (L) |
||

ellipticity behaviour | ||

Elliptical waveforms SGEQ9 SEARCH P | ||

e=1.0 (C) e=0.8 e=0.6 e=0.4 e=0.3 e=0.2 e=0.1 e=0.0 (L) |

- For lower frequency (up to 500 Hz) the curves seems following the behaviour of 1/f^2, like in Wen&Chen formula
- For upper frequency, the results are probably related to algorithm approximation, this is quite confirmed by test with upTDF=8 (instead of 4) for SGQ9
- For higher Q, performances worse, because it enters the group error, other than phase error. It would be nice to identify the correlation between the two effects

- Network: 3-fold and 4-fold, no invariant detectors.
- Waveforms: Focus on SG, linear and elittical polization. Study the results on variation on polarization values. Could be interesting to see RingDown (nearer to astrophysical binaries?)
- Search: R and E (other polarization if there is space.)
- SNR: characterize at fixed network SNR. Consider a study of reduced waveforms varying SNR.

Low-latency localization of sources of transient Gravitational Waves with generic waveforms

Assume that a low-latency GW detection is triggering a low latency GW follow-up for estimation purposes

- A. Methodological investigation: understanding and comparing performances simulations vs network SNR

LHV 32Hz-2kHz, ADE design spectral sensitivity, with Gaussian noise

R and P(new) searches

SG as a function of central frequency, Q (3-100), ellipticity

Ring-down, WNB, …

- B. Performances on astrophysical source distributions

Simulations with astrophysical motivated source populations (best if multimessenger prompt follow-up is motivated)

NSBH, BBH uniform in volume

NS excitations, galactic mode

cosmic strings

P(new) search LHV, LHV+Kagra ?

- C. Lesson learned for advanced detectors observations

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Topic revision: r2 - 28 May 2015, MarcoDrago

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