Jishnu Suresh

I am a Henri Poincaré Fellow at the Observatoire de la Côte d'Azur, Nice, France. My primary research focuses on the search for the stochastic gravitational-wave background (SGWB), which could originate from cosmological or astrophysical sources, using data from the LIGO, Virgo, and KAGRA (LVK) detectors. We have placed the most stringent bounds on the energy density of SGWBs using the latest LVK observational data and produced the first upper-limit maps of the gravitational-wave sky across every frequency bin. We expect that current efforts will lead to significant progress in the coming years, potentially resulting in the first detection of SGWBs.

During my Ph.D., I worked on various aspects of alternative theories of gravity, exploring the thermodynamic properties of black hole solutions through the lens of Geometrothermodynamics, a formalism based on concepts from differential geometry. In the past, I also examined different dark energy models and methods to characterize them.

Academic history (in the reverse chronological order):

• Henri Poincaré Fellow, October 2024 – present
  ARTEMIS,
  Observatoire de la Côte d'Azur
  Nice, France.
• Post-doctoral fellow, October 2021 – September 2024
  Centre for Cosmology, Particle Physics and Phenomenology (CP3),
  Institut de Recherche en Mathématique et Physique (IRMP),
  Université catholique de Louvain, Belgium.
• Post-doctoral fellow, February 2019 – September 2021
  Institute for Cosmic Ray Research (ICRR),
  University of Tokyo, Japan.
• Post-doctoral fellow, August 2016 – January 2019
  The Inter-University Centre for Astronomy and Astrophysics (IUCAA), Pune, India.
• Ph.D. Physics, September 2014 – August 2016
  Cochin University of Science and Technology (CUSAT), Kochi, Kerala, India.
• University Grant Commission Research Fellow, November 2012 – September 2014
  Department of Physics,
  Cochin University of Science and Technology (CUSAT), Kochi, Kerala, India.

You can find the details in my CV

Group

I am a Henri Poincaré Fellow at the Observatoire de la Côte d'Azur in the ARTEMIS research group led by Nelson Christensen. The ARTEMIS group has been contributing a significant effort to the search for gravitational wave background (GWB) and the publication of its results. Furthermore, the group actively works on developing and maintaining different analysis pipelines used in different LIGO-Virgo-KAGRA group. For more details: ARTEMIS

My research interests

My primary research interest at present is searches for gravitational wave background, superposition of sources too weak to detect individually, using ground-based interferometers.

Topics of my interest include:

• Gravitational Waves (GW)
  • Sources and searches for persistent Stochastic GW Background (SGWB)
  • Sources and searches for continuous wave sources
  • Quasi normal mode calculations
• Theoretical aspects of general theory of gravity
  • Modified theories of gravity
  • Black hole thermodynamics
  • Geometrothermodynamics

Key research

• 
  "Very fast stochastic gravitational wave background map making using folded data"
  A. Ain, J. Suresh, S. Mitra, Phys.Rev.D 98 (2018) 024001.

  Introduced PyStoch, a HEALPix-based map-making pipeline for the gravitational-wave background. Together with data folding, it made radiometer searches roughly ten thousand times faster — all-sky mapping now runs in minutes on a laptop — and produces sky maps at every frequency bin, the foundation for the ASAF search.

• 
  "Jointly setting upper limits on multiple components of an anisotropic stochastic gravitational-wave background"
  J. Suresh, D. Agarwal, S. Mitra, Phys.Rev.D 104 (2021) 102003.

  Developed a method to jointly estimate multiple spectral components of an anisotropic gravitational-wave background, properly accounting for the covariance between spectral shapes. Applied to Advanced LIGO data (O1–O3a), it produced the first simultaneous multi-component directional upper limits, showing that single-index analyses can bias the recovered amplitudes.

• 
  "All-sky, all-frequency directional search for persistent gravitational waves from Advanced LIGO's and Advanced Virgo's first three observing runs"
  LIGO-Virgo-KAGRA Collaboration (incl. J. Suresh), Phys.Rev.D 105 (2022) 122001.

  The first all-sky, all-frequency (ASAF) directional search for persistent, narrowband gravitational waves, using data from the first three observing runs of Advanced LIGO and Virgo. Enabled by data folding and the PyStoch pipeline, the analysis placed 95% confidence strain upper limits at every frequency bin and sky location and identified candidate pixel–frequency pairs for follow-up continuous-wave searches.

• 
  "Measurement of the cross-correlation angular power spectrum between the stochastic gravitational wave background and galaxy overdensity"
  K. Z. Yang, J. Suresh, G. Cusin, S. Banagiri, N. Feist, V. Mandic, C. Scarlata, I. Michaloliakos, Phys.Rev.D 108 (2023) 043025.

  First measurement of the cross-correlation angular power spectrum between the gravitational-wave background, measured with Advanced LIGO O3 data, and the galaxy overdensity from the SDSS catalog. Using a Bayesian framework, we set the first upper limits on the astrophysical kernel describing gravitational-wave emission at galactic scales.

• 
  "Probing ensemble properties of vortex-avalanche pulsar glitches with a stochastic gravitational-wave background search"
  F. De Lillo, J. Suresh, A. Depasse, M. Sieniawska, A. L. Miller, G. Bruno, Phys.Rev.D 107 (2023) 102001.

  A novel search for the gravitational-wave background produced by superfluid vortex-avalanche glitches of Galactic pulsars, using data from the first three LIGO–Virgo observing runs. Finding no signal, we placed upper limits on the background energy density and derived the first constraints on ensemble glitch properties — the average glitch duration and the average radial displacement of superfluid vortices.

Codes and data

• 
  PyStoch — Co-developed the GWB map-making pipeline. Maintaining the pipeline. [PyPI] [GitHub]
• 
  gwfolding — Folding of Stochastic Intermediate Data (SID) to one sidereal day for gravitational-wave background searches. Data production & maintainer: Jishnu Suresh. [PyPI] [GitHub]

  • The GWOSC release of these datasets can be found at:

Publications and pre-prints

Some of my recent publications and preprints, in the reverse chronological order, is given below. The entire list of publications can be found at iNSPIRE and ORCiD.

Updated automatically from INSPIRE-HEP.

1. T. Regimbau, J. Suresh, "A mock data challenge for next-generation detectors", [arXiv:2506.12237].
2. S. Venikoudis, F. De Lillo, K. Janssens, J. Suresh, G. Bruno, "Impact of correlated magnetic noise on directional stochastic gravitational-wave background searches", Phys.Rev.D 111 (2025) 8, 082005 [arXiv:2411.11746].
3. F. De Lillo, J. Suresh, "Estimating Astrophysical Population Properties using a multi-component Stochastic Gravitational-Wave Background Search", Phys.Rev.D 109 (2024) 10, 103013 [arXiv:2310.05823].
4. K. Z. Yang, J. Suresh, G. Cusin, S. Banagiri, N. Feist, V. Mandic, C. Scarlata and I. Michaloliakos, "Measurement of the cross-correlation angular power spectrum between the stochastic gravitational wave background and galaxy overdensity", Phys.Rev.D 108 (2023) 4, 043025, [arXiv:2304.07621].
5. D. Agarwal, J. Suresh, S. Mitra, A. Ain, "Angular power spectra of anisotropic stochastic gravitational wave background: developing statistical methods and analyzing data from ground-based detectors", Phys.Rev.D 108 (2023) 2, 023011, [arXiv:2302.12516].
6. F. De Lillo, J. Suresh, A. Depasse, M. Sieniawska, A. L. Miller and G. Bruno, "Probing Ensemble Properties of Vortex-avalanche Pulsar Glitches with a Stochastic Gravitational-Wave Background Search", Phys.Rev.D 107 (2023) 10, 102001, [arXiv:2211.16857].

Contact details:

Address:
ARTEMIS, Observatoire de la Côte d'Azur
Boulevard de l'Observatoire, CS 34229
06304 Nice Cedex 4, France.

E-mail:
jishnu.suresh'at'oca.eu