Photo-z Workshop for Large Surveys 2017

Scientific Rationale

Photometric redshift is a classical technique to infer redshifts of objects using photometric data, but its importance has been rapidly increasing in recent years.  On-going/Up-coming large imaging surveys such as DES, Euclid, KiDS, HSC, LSST and WFIRST all rely heavily on photometric redshifts.  However, it is a big challenge to achieve the required photometric redshift accuracy for various science cases, especially weak-lensing cosmology.  It is a common challenge to all the surveys, and the Photo-z Workshop for Large Surveys 2017 offers an opportunity for people involved in photometric redshift efforts to get together, share problems, and join forces to address them together.


May 17 (Wed):   Joint session with HSC  (20min talk + 10min questions)

chair: Tanaka
13:30-14:00 overview and recent results from HSC (Takada)
14:00-14:30 overview and recent results from KiDS (Hildebrandt)
14:30-15:00 overview and recent results from DES (Hartley)
15:00-15:30 break
15:30-16:00 overview of Euclid (Kuijken)
16:00-16:30 overview of WFIRST (Capak)
16:30-17:00 overview of LSST (Schmidt)


May 18 (Thu):  Photo-z workshop

chair: Paltani
on-going surveys: DES
09:00-09:20 Clustering redshift approach in Y1 (Miquel)
09:20-09:40 Y3 roadmap and joint WL, photo-z selection (Bernstein)
09:40-10:00 Limitations of spectroscopy (Hartley)
10:00-10:30 break
On-going surveys: KiDS
10:30-10:45 KiDS multi-colour photometry (Kuijken)
10:45-11:00 KiDS 4-band photo-z performance with different methods (Bilicki)
11:00-11:15 KiDS-450 and KiDS-VIKING (Hildebrandt)
11:15-11:30 KiDS photo-z estimation based on machine learning (Amaro)
11:30-13:00 lunch
On-going Surveys: HSC (each slot includes time for questions and discussions)
chair: Schmidt
13:00-13:20 Overview of HSC photo-z’s (Tanaka)
13:20-13:40 Loss/Risk functions, ‘best’ point estimates and a new NN code (Mineo)
13:40-14:00 Recent results from deep learning (Nakano)
14:00-15:00 photo-z calibration challenges (Hildebrandt/Capak)
15:00-15:30 break
15:30-17:00 group discussion

May 19 (Fri): Photo-z workshop

9:00-10:00 group discussion continued.
10:00-10:15 short break
chair: Coupon
10:15-11:00 report from each group (10+5min each)
11:00-12:00 upcoming surveys: WFIRST
12:00-13:00 lunch
Upcoming Surveys: Euclid
chair: Hildebrandt
13:00-13:15 Photo-Z Requirements and Baseline Pipeline (Paltani)
13:15-13:30 Prescription for Galactic extinction in Euclid (Galametz)
13:30-13:45 Application of clustering methods for the reconstruction of redshift distributions in MICE2 (Scottez)
13:45-14:00 The Complete Calibration of the Color-Redshift Relation (C3R2) Survey (Masters)
14:00-14:15 Training sample machine (Coupon)
Upcoming surveys: LSST
14:15-14:30 LSST photo-z overview (Schmidt)
14:30-14:45 Incompleteness models (Hartley)
14:45-15:00 Codes used in data challenge/Gpz (Jarvis)
15:00-15:15 Validating cross-correlation calibration on simulations (Morrison)
15:15-15:30 Photo-z PDF tests and storage (Malz)
15:30-16:00 break
16:00-17:00 discussion


The workshop will be held at the Tohoku University in Sendai, Japan.  The astronomy department is located on a hill, Aobayama, and is easily accessible from the Sendai city center by subway. The workshop will be held at the Aoba Hall, located on the ground floor of the Science Complex C in this map.   Detailed access information is here. If you have any questions, please feel free to ask Masayuki  (who used to live in Sendai).  Also, check out a very nice website about Sendai.


The participant list will be updated as we receive registrations.

Name Affilliation Survey Involved
Jean Coupon University of Geneva Euclid, HSC
Hendrik Hildebrandt Arglander-Insitut für Astronomie, University of Bonn Euclid, KiDS
Stéphane Paltani University of Geneva Euclid
Audrey Galametz MPE Euclid
Atsushi J. Nishizawa Nagoya University HSC
Daniel Masters Infrared Processing and Analysis Center, Caltech Euclid, WFIRST
Valeria Amaro University of Naples Federico II Euclid, KiDS
Maciej Bilicki Leiden Observatory, Leiden University, the Netherlands KiDS
Christopher Morrison University of Washington KiDS, LSST
Masayuki Tanaka NAOJ HSC
Daniel Stern JPL/Caltech Euclid
Will Hartley UCL Euclid, LSST, DES
Filipe Abdalla UCL DES
Massimo Brescia INAF – Astronomical Observatory of Capodimonte Euclid, KiDS
Stefano Cavuoti University of Naples Federico II Euclid, KiDS, LSST
Scottez Institut d’Astrophysique de Paris Euclid
Konrad Kuijken Leiden Observatory KiDS, Euclid
Gary Bernstein University of Pennsylvania DES
Sam Schmidt UC Davis LSST
Alex Malz New York University LSST
Ramon Miquel IFAE Barcelona DES, Euclid, LSST
Jun Nakano Kanazawa Institute of Technology HSC
Zahra Gomes University of Oxford Euclid, LSST
Peter Capak Caltech Euclid, HSC, WFIRST
Matt Jarvis Oxford Euclid, LSST
Bahram Mobasher UC Riverside Euclid
Francisco Castander ICE, IEEC-CSIC DES, Euclid, LSST, PAU
Masahiro Takada Kavli IPMU HSC
Masamune Oguri Univ of Tokyo HSC


The banquet on Wednesday will be in down-town Sendai.  Details will be announced later.  If you signed up for banquet, we will ask you to pay 5,000JPY(faculty members and post-docs) or 3,000JPY(students) at the registration desk.


Please book a hotel by yourself.  The SOC/LOC did not realize until recently that there is a local festival on the 20th and 21st ( – Japanese page only).  It seems that there are not many available rooms left, especially over the weekend.  Please book early!  Here are a few suggestions from the LOC.
Metropolitan hotel

Hotel Monterey Sendai

LibraryHotel Sendai Ekimae

Richmond Hotel Sendai Ekimae

Comfort Hotel Sendai Nishiguchi


Peter Capak (Caltech), Jean Coupon (Geneva), Hendrik Hildebrandt (Bonn), Ben Hoyle (LMU), Sogo Mineo (NAOJ), Atsushi Nishizawa (Nagoya), Stephane Paltani (Geneva), Samuel Schmidt (UC Davis), Masayuki Tanaka (NAOJ)


This workshop is supposed by MEXT Grant-in-Aid for Scientific Research on Innovative Area, “Cosmic Acceleration”.

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