Precision Cosmology

with Strong Lensing Time Delays

This workshop aims to bring together researchers working on aspects of strong gravitational lensing related to time-delay cosmography, and will be held the same week as the annual face-to-face TDCOSMO Collaboration meeting. The workshop will focus on recent progress and future prospects in areas such as lens modeling, lensed supernovae, time-delay measurements, substructure studies, and synergies with current and upcoming facilities and datasets. We hope the meeting will foster in-depth discussions and new collaborations within the community.

Dates & Location

August 3–5, 2026
School of Science Bldg. No.4, Room 1220 (2nd floor)
University of Tokyo
7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan

Registration

Presentations at this workshop are by invitation only. Those who wish to join as participants may register by filling out this form. The deadline for registration as a participant is July 24.

Confirmed Participants

List of Confirmed Participants

Program

Monday, August 3

10:00 - Kenneth Wong, Opening Remarks

Session Chair: Eric Paic

10:10 - Kenneth Wong, TDCOSMO: Cosmological Constraints from Strong Lensing Time Delays

10:30 - Devon Williams, Modeling JWST NIRCam Quads: WFI2033, HE0435, and PG1115

10:50 - Pritom Mozumdar, Precision kinematics of lens galaxy from NIRSpec-JWST data for precision cosmology

Break / Discussion (11:10-11:40)

11:40 - James Jee, TBA

12:00 - Jeremy Lim, Illuminating the Dark Matter particle from lensed star transients

12:20 - Alex Chow, Testing Axion Dark Matter with Lensing Anomalies Statistics

Lunch (12:40 - 14:00)

Session Chair: Kenneth Wong

14:00 - Sherry Suyu, Cosmology and neutrinos with lensed supernovae

14:20 - Christopher Storfer, Initial Models of SN 2025wny (SN Winny) from Keck NIRC2 Imaging

14:40 - Yiwei He, Diagnosing the Ellipticity-H0 Degeneracy: Joint Constraints from Lensed SNe Ia and Extended Source Photometry

Break / Discussion (14:55-15:25)

15:25 - Claudio Grillo, Lessons learnt from SN Refsdal

15:45 - Ana Acebron, The Next Step in Galaxy Cluster Strong Lensing: Modelling the Surface Brightness of Multiply Imaged Sources

Break / Discussion (16:05-16:35)

16:35 - Guanlin Liu, Modeling J0659+1629 for an Independent constraint on the Hubble Constant

16:55 - Ryan Brady, On Using Doubly Imaged Quasars for Time-Delay Cosmography

17:10 - Hrvoje Krizic, ALPACA: Semi-automated GPU-accelerated strong-lens modelling for time-delay cosmography

Tuesday, August 4

Session Chair: Sherry Suyu

10:00 - Shawn Knabel, Spatially Resolved Kinematics with JWST NIRSpec IFU

10:20 - Han Wang, The Stellar IMF and Dark Matter Halo of ESO0286: Constraints from Strong Lensing and Dynamics

10:40 - William Sheu, Constraints using source kinematic IFU information

Break / Discussion (11:00-11:30)

11:30 - Anupreeta More, Lensed Kilonovae

11:50 - Kah Chun Lai, Lensing Anomalies among Multiply-Lensed SNIa

Lunch (12:10 - 13:30)

Session Chair: Masamune Oguri

13:30 - Zachary Scofield, Dark Matter Substructure Detection with Flexion

13:50 - Amruth Alfred, Role of External Shear in Concealing Lensing Anomalies

14:10 - Momoka Fujikawa, The stellar and dark matter distributions in early-type galaxies measured by stacked weak gravitational lensing

14:25 - Yuma Iwasaki, The power spectrum of substructures of dark matter halos

Break / Discussion (14:40-15:10)

15:10 - Hanchun Jiang, Optimal delensing method for improving constraints on PGWs for LiteBIRD

15:30 - Hikaru Saito, Constraining neutrino mass with Planck+ACT CMB, DESI BAO, and Subaru HSC WL with a differentiable likelihood

15:45 - Amiri Hirayama, 21cm fluctuation caused by primordial magnetic fields

Break / Discussion (16:00-16:30)

Free time (16:30-19:00)

Workshop Dinner (19:00)

Wednesday, August 5

Session Chair: Kaiki Inoue

10:00 - Ashish Kumar Meena, Exotic image formations in cluster lenses

10:20 - Sangjun Cha, BCG–Halo Offset Freedom and Time-Delay Predictions in Cluster Strong Lensing: A Free-form Perspective

10:40 - Adi Zitrin, (Some) systematics in time delay estimates in clusters

Break / Discussion (11:00-11:30)

11:30 - Giacomo Queirolo, Studying LOS shear in hydrosimulated lenses - challenges and opportunities

11:50 - Carlos Melo Carneiro, Stress-Testing Lensing-Only Slope Measurements / Lens Modelling

12:10 - Alessandro Sonnenfeld, Selection effects in time-delay lensing

Lunch (12:30 - 13:50)

Session Chair: Kenneth Wong

13:50 - Elias Mamuzic, Time Delay Inference using an LSTM Network

14:10 - Felipe Urcelay, Multi–Source-Plane Cosmography with the Carousel Lens

14:30 - Daniel Johnson, Constraining the mass-sheet degeneracy with compound lensing

Break / Discussion (14:50-15:20)

Breakout groups (15:20-16:20)

Breakout group presentations (16:20-16:50)

16:50 - Masamune Oguri, Workshop Summary/Closing

Access

For overseas visitors, Tokyo is serviced by the Narita (NRT) and Haneda (HND) airports. Haneda is conveniently located close to downtown and is connected to the metro systems, while Narita is farther away and accessed via high-speed rail (either JR Narita Express or Keisei Skyliner) or airport bus.

Visitors who are new to Japan should consider buying a Suica or Pasmo. This is a pre-paid electronic fare card that can be used for trains, subways, and buses. It can be obtained at JR stations or the Tokyo monorail station at Haneda for a 500 yen deposit, which is refundable along with the remaining balance when you leave (see the web pages for details and restrictions). It can be recharged at train/subway stations. Suica/Pasmo can also be used at convenience stores and many restaurants.

To access the University of Tokyo Hongo Campus, the nearest subway/train stations are Hongo-sanchome (本郷三丁目), Todaimae (東大前), and Nezu (根津). There are also buses available from other stations a bit further away. The workshop venue (School of Science Building #4) is shown on the Google map embedded below.

UTokyo Access map: English
UTokyo Hongo Campus map: English

Workshop Dinner

The workshop dinner will be held on the evening of Tuesday, August 4. We will be chartering a yakatabune (a traditional Japanese house boat) for a cruise in the Sumida river. The cruise departs at 7 pm (tentative) from Azumabashi pier in Asakusa, and will last ~2.5 hours. Details can be found here.

Scientific Organizing Committee

  • Kaiki Inoue
  • Masamune Oguri
  • Eric Paic
  • Sherry Suyu
  • Kenneth Wong
  • Naoki Yoshida

Local Organizing Committee

  • Guanlin Liu
  • Eric Paic
  • Kenneth Wong
  • Naoki Yoshida

Contact

For inquiries, please contact the LOC chair at:
kcwong19 [at] gmail.com

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