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CosmoVerseSchool@Sofia 2026

25–29 May 2026
Sofia, Bulgaria
Europe/Sofia timezone

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Contribution List

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  1. 1. Registration
    25/05/2026, 08:00
  2. 2. School Opening Talks
    1. Eleonora Di Valentino - Vice-Chair of COST Action CA21136 (University of Sheffield, UK), 2. Neli Koseva - Scientific Secretary-General of BAS (Bulgarian Academy of Sciences), 3. Denitsa Staicova (INRNE, Bulgarian Academy of Sciences), 4. Lilia Anguelova (INRNE, Bulgarian Academy of Sciences), 5. Siyang Li (University of California, Berkeley, USA)
    25/05/2026, 08:45
  3. 3. The Hubble Tension & the distance ladder(s)
    Dr Louise Breuval
    25/05/2026, 09:30
  4. 4. Coffee Break
    25/05/2026, 11:00
  5. 5. Measuring astronomical distances with Cepheid variables
    Teresa Sicignano (Scuola Superiore Meridionale - INAF OACN)
    25/05/2026, 11:30
  6. 10. Lunch Break
    25/05/2026, 13:00
  7. 11. The Cepheid metallicity dependence & how to measure stellar abundances
    Louise Breuval, Teresa Sicignano (Scuola Superiore Meridionale - INAF OACN)
    25/05/2026, 14:30
  8. 12. Coffee Break
    25/05/2026, 16:00
  9. 13. Exercises & Notebooks
    Louise Breuval, Teresa Sicignano (Scuola Superiore Meridionale - INAF OACN)
    25/05/2026, 16:30
  10. 14. Introduction to the Tip of the Red Giant Branch: Theories and Observations
    Dr Siyang Li
    26/05/2026, 09:30
  11. 15. Coffee Break
    26/05/2026, 11:00
  12. 16. How to Measure Stars: Methods and Challenges of Photometry
    Dr Kayla Owens
    26/05/2026, 11:30
  13. 17. Lunch
    26/05/2026, 13:00
  14. 18. An Overview of TRGB Data Sets for the Data Challenge
    Kayla Owens
    26/05/2026, 14:30
  15. 19. Coffee Break
    26/05/2026, 16:00
  16. 20. Measuring Distances to Type Ia Supernova Host Galaxies with the TRGB
    Siyang Li
    26/05/2026, 16:30
  17. 21. CosmoVerse Data Challenge TRGB Tutorial
    Siyang Li
    27/05/2026, 09:30
  18. 22. Coffee Break
    27/05/2026, 11:00
  19. 23. Type Ia Supernova as a Standardizable Candle
    Yukei Murakami
    27/05/2026, 11:30
  20. 24. Group Photo
    27/05/2026, 13:00
  21. 25. Lunch
    27/05/2026, 13:10
  22. 26. Type Ia Supernova in Distance Ladder + Coding Demo
    Yukei Murakami
    27/05/2026, 14:30
  23. 27. Coffee Break
    27/05/2026, 16:00
  24. 28. Wrapping-up
    Siyang Li
    27/05/2026, 16:30
  25. 29. Conference Dinner
    27/05/2026, 19:00
  26. 30. Systematics in SNe Ia cosmology & Outlook in the Era of LSST, Roman, and Euclid
    Yukei Murakami
    28/05/2026, 09:30
  27. 31. Coffee Break
    28/05/2026, 11:00
  28. 32. Synthesis & Wrap-Up What Have We Learned?
    Siyang Li
    28/05/2026, 11:30
  29. 33. Lunch Break
    28/05/2026, 13:00
  30. 54. (An)Isotropy in Pantheon+ and Type Ia supernova samples: intrinsic limits of directional tests
    Antonio Quintana Estellés (IFF CSIC)
    28/05/2026, 15:10

    The use of methods that investigate the value of the Hubble constant H0 in different patches (60 or 90 size) across the sky to probe the statistical isotropy of the Universe using large SNe Ia databases has led to contradictory claims of either anisotropy or isotropy. The anisotropy directions vary amongst research works. The objective of this paper is to clarify the abovementioned claims and...

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  31. 59. An AI-Assisted personalized literature explorer: Contextual Language model Assisted arXiv Retrieval (CLArXivR).
    Umut Emek Demirbozan (Institut Fisica dáltes Energies)
    28/05/2026, 15:10

    An AI-Assisted literature explorer: Contextual Language model Assisted arXiv Retrieval (CLArXivR). I will present the CLArXivR package, which assists researchers in selecting and prioritizing abstracts based on their publication history and a domain library defined by the researcher. The package automatically identifies the most similar papers, ranks them, and provides comparative summaries of...

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  32. 48. Beyond ΛCDM: Teleparallel Gravity
    Vasiliki Karanasou (University of Tartu)
    28/05/2026, 15:10

    The ΛCDM model, based on General Relativity, has successfully explained a wide range of cosmological observations. However, in recent years, several cosmological tensions have emerged and at the same time, the nature of dark matter and dark energy - the latter introduced to explain the accelerated expansion of the Universe - remains unknown. These issues suggest that our current understanding...

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  33. 46. Constraining DDE Models with AdS-to-dS and Similar Late-Time Transitions
    Mine Gokcen (Istanbul Technical University)
    28/05/2026, 15:10

    With the release of DESI DR2, dynamical dark energy (DDE) models gained unprecedented attention as model candidates to release the current cosmological tensions. However, majority do not perform well in relaxing the H0 tension compared to some of the other novel theoretical and phenomenological models in the literature, such as the LsCDM model that can be explained by an AdS-to-dS transition...

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  34. 62. Cosmology with Gaia - catalogs of clusters, voids and local densities based on quasars
    Nestor Arsenov (Institute of Astronomy, Sofia; Konkoly Observatory, Budapest)
    28/05/2026, 15:10

    Understanding the formation and evolution of the cosmic web of galaxies is a fundamental goal of cosmology, using various tracers of the cosmic large-scale structure at an ever wider range of redshifts. Our principal aim is to advance the mapping of the cosmic web at high redshifts using observational and synthetic catalogues of quasars (QSOs), which offer a powerful probe of structure...

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  35. 45. Early gravity transitions and the Hubble tension
    Lorenzo Baldazzi (Istituto Nazionale di Fisica Nucleare)
    28/05/2026, 15:10

    Modifications of gravity at early cosmological epochs are known to alleviate the Hubble tension better than late-time ones. The majority of such early-time Modified Gravity models affects the pre-recombination physics, and the Transitional Planck Mass (TPM) model makes no exception.
    In this lightening talk I will briefly discuss the core idea behind this model, its intrinsic predisposition to...

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  36. 63. Exploring the stability of f(Q) cosmology near general relativity limit with different connections
    Laxmipriya Pati (University of Tartu)
    28/05/2026, 15:10

    I will explain the stability of cosmological background evolution near the general relativity regime across radiation, matter, dark energy, and geometric dark energy dominated eras. Our results show that for the standard connection set 1 the general relativity regime can be realized in two ways and both exhibit stable behavior throughout all evolutionary epochs. Conversely, for the alternative...

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  37. 52. Generalized tension metrics for multiple cosmological datasets
    Matías Leizerovich
    28/05/2026, 15:10

    We introduce a novel estimator to quantify statistical tensions among multiple cosmological datasets simultaneously. This estimator generalizes the Difference-in-Means statistic, QDM, to the multi-dataset regime. Our framework enables the detection of dominant tension directions in the shared parameter space. It further provides a geometric interpretation of the tension for the two- and...

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  38. 57. Hubble Parameter Estimation with CORN
    Nicola Principi Cavaterra (Narodowe Centrum Badań Jądrowych (NCBJ))
    28/05/2026, 15:10

    Measuring the expansion rate of the Universe is a central challenge in cosmology, particularly due to the persistent Hubble tension.

    The cosmic chronometer (CC) approach is a promising method for probing the expansion history of the Universe independently from the underlying cosmological model. However, CC measurements are still affected by several systematic uncertainties.

    In this brief...

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  39. 50. Impact of Fibber Assignment in the study of clustering using the two and three point correlation functions
    Luis Miguel Hernandez
    28/05/2026, 15:10

    Impact of Fibber Assignment in the study of clustering using the two and three point correlation functions

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  40. 47. Is the Universe Isotropic? -Maybe!!
    Vasudev Mittal (School of Physics, The University of Sydney)
    28/05/2026, 15:10

    The Cosmological Principle (CP) asserts that the universe is isotropic and homogeneous on large scales. It attributes the CMB thermal dipole to our local peculiar motion, hence giving rise to the term kinematic dipole. If this attribution is correct, then all-sky surveys of other cosmological probes should show a similar dipole in their distribution across the sky. More than forty years ago,...

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  41. 60. Lensing ratios in the Precision Cosmology Era
    Gisela Cristina Camacho Ciurana (ICE-CSIC)
    28/05/2026, 15:10

    Increasingly precise observations are beginning to expose potential cracks in the standard cosmological model, from the Hubble constant tension to emerging hints of evolving dark energy. Resolving whether these point to new physics, and uncovering the nature of dark matter and dark energy, requires precise measurements of cosmic geometry and the growth of structure. The Dark Energy Survey...

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  42. 35. Lightning Talks Session
    28/05/2026, 15:10

    Participants are invited to present 3 minute lightning talk

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  43. 61. Probing Large-Scale Structure with angular density and redshift fluctuations.
    Mar Pérez Sar (Instituto de Astrofísica de Canarias)
    28/05/2026, 15:10

    The accelerated expansion of the Universe remains one of the central open problems in cosmology. While traditional probes such as the Cosmic Microwave Background, Type Ia Supernovae, and Baryon Acoustic Oscillations have enabled precision cosmology, persistent tensions between independent measurements highlight the need for complementary observables to validate existing results and address...

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  44. 53. Probing Three-Form Dark Energy with a Gaussian Potential
    Javier Ortega
    28/05/2026, 15:10

    The late-time acceleration of the Universe's expansion is well established observationally, yet the nature of the dark energy component driving it remains an open question. In this talk, I will present a cosmological model in which dark energy can be described by a minimally coupled three-form field with a Gaussian self-interaction potential. Such a field naturally generates an effective...

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  45. 56. Recalibration of the Cosmic Flows 4 Catalogue: A Study of the Systematics
    Jose Antonio de Jesus Najera Quintana (University of Portsmouth, UK)
    28/05/2026, 15:10

    The Cosmic Flows 4 (CF4) catalogue compiles ~56,000 extragalactic distance
    measurements from eight independent methods — Type Ia supernovae,
    Tully–Fisher, Fundamental Plane, surface brightness fluctuations, Type II
    supernovae, TRGB, Cepheids, and masers. A pairwise consistency analysis
    reveals significant inter-method tensions, particularly involving the
    Tully–Fisher relation...

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  46. 49. Shedding some light on the Dark Sector with Galaxy–CMB Lensing Cross-correlation
    Miguel Antonio Sabogal Garcia (Università di Trento)
    28/05/2026, 15:10

    Cosmological parameters represent fundamental quantities that offer insights into the structure, composition, and dynamics of the universe. Despite the remarkable progress of modern cosmology, significant challenges persist, with cosmological tensions emerging as a focal point. In this talk, I will present constraints on extensions of the standard cosmological model derived from DESI geometric...

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  47. 58. Sign-Switching Dark Energy: Smooth Transitions with Recent DESI DR2 Observations
    Beñat Ibarra Uriondo (EHU, Basque Country University)
    28/05/2026, 15:10

    Sign-switching dark energy provides a novel mechanism for modifying the late-time expansion history of the Universe without invoking additional fields or finely tuned initial conditions. In this work, we investigate a class of background–level cosmological models in which the dark energy contribution changes sign at a transition redshift z†, producing a sharp deviation from standard ΛCDM...

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  48. 51. The quest for primordial non-Gaussianity: Opportunities and Challenges
    Toka Alokda (Argelander-Institute for Astronomy, University of Bonn)
    28/05/2026, 15:10

    Primordial non-Gaussianity (PNG) is the smoking gun for non-canonical inflationary scenarios. While measurements from the CMB has hit the cosmic variance limit, the large-scale structure (LSS) holds great potential for improvement and the possibility for a verdict on our early universe. with the massive amount of data from up-and-coming surveys of the LSS, alongside higher-order statistics and...

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  49. 55. Validation of BAO measurements in Fourier space and Cosmological Parameters inference with DES and DESI
    Nicola Deiosso (CIEMAT)
    28/05/2026, 15:10

    The Dark Energy Spectroscopic Instrument (DESI) Data Release 2 (DR2) enables precision cosmological inference beyond the standard ΛCDM model, exploring extensions such as massive neutrinos and time-varying dark energy (w₀–wₐ). The analysis includes a comprehensive validation of BAO measurements through mock-based covariance estimation and robustness tests in both configuration and Fourier...

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  50. 64. Constraining high-z reionization with Cosmological Data
    Hanyu Cheng
    28/05/2026, 15:14

    I discuss model-independent reconstructions of the reionization history using Gaussian processes. We utilize these reconstructions to place robust bounds on exotic energy injections and decaying particle models.

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  51. 36. Free Afternoon
    28/05/2026, 16:00
  52. 38. Work on data challenge
    29/05/2026, 09:30
  53. 39. Coffee Break
    29/05/2026, 11:00
  54. 40. Work on data challenge
    29/05/2026, 11:30
  55. 41. Lunch
    29/05/2026, 13:00
  56. 42. Work on data challenge
    29/05/2026, 14:30
  57. 43. Coffee Break
    29/05/2026, 16:00
  58. 44. Work on data challenge
    29/05/2026, 16:30
  59. 9. Coffee Break
  60. 34. Day 4 - Afternoon Session
  61. 37. Day 5 - Morning Session
  62. 7. Lunch Break
  63. 6. TBA
    Louise Breuval
  64. 8. TBA
    Teresa Sicignano (Scuola Superiore Meridionale - INAF OACN)