# Persistent post-merger coherence and redshift-dependent frequency shifts in GWTC-1

**URL:** <https://ask.igwn.org/t/persistent-post-merger-coherence-and-redshift-dependent-frequency-shifts-in-gwtc-1/1563>\
**Category:** Publications\
**Created:** [August 3, 2026, 7:12pm UTC](https://ask.igwn.org/t/persistent-post-merger-coherence-and-redshift-dependent-frequency-shifts-in-gwtc-1/1563 "2026-08-03T19:12:04Z")\
**Posts on this page:** 1\
**Page:** 1

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**Author:** ![HugoDemicheri](https://avatars.discourse-cdn.com/v4/letter/h/e47774/32.png) [@HugoDemicheri](https://ask.igwn.org/u/HugoDemicheri)\
**Post date:** [August 3, 2026, 7:12pm UTC](https://ask.igwn.org/t/persistent-post-merger-coherence-and-redshift-dependent-frequency-shifts-in-gwtc-1/1563/1 "2026-08-03T19:12:04Z")

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Hello LIGO-Virgo-KAGRA community,

I would like to share a recent analysis of public LIGO GWTC-1 data performed by the DFH Cosmology - Uruguay.

Using open data, I find three observational features that are not expected in standard GR ringdown:

1. Persistent coherence: The post-merger signal in GW150914 remains coherent for longer than ~0.25 seconds after merger.
2. Redshift trend: The main ringdown frequency appears to shift with source redshift. Distant mergers look systematically “detuned” compared to nearby ones.
3. Implications: Within the Dissipative Field Holography framework, this suggests the universe may retain information about the merger as late-time echoes.

Testable predictions:  
As part of this work we made concrete predictions for targeted echo searches:

- GW190521: echo expected ~0.50 seconds after merger
- GW231123: echo expected ~0.87 seconds after merger

I noticed the performed echoes searches for GWTC-4.0/5.0 including these events.  
I am happy to discuss any follow-up.

Best regards,  
Hugo Demicheri  
DFH Cosmology Quantum Gravity LAB - Uruguay