• Skip to main content
  • Skip to primary sidebar
  • Skip to footer

Dark Energy Spectroscopic Instrument (DESI)

  • / science /
    • science overview
    • cosmology and dark energy
    • redshifts and distance
    • mapping the universe
    • the DESI science mission
    • the DESI survey
    • imaging surveys
  • / instrument /
    • instrument overview
    • telescope
      • tohono o’odham
    • corrector
    • focal plane system
    • fiber system
    • spectrograph
    • instrument control system
    • data systems
    • bringing DESI to life
      • commissioning Instrument
      • protoDESI
  • / collaboration /
    • DESI team
    • DESI builders
    • collaborating institutions
    • sponsors
    • code of conduct
    • vendors
    • collaboration policies
  • / press /
    • announcements
    • in the news
    • press releases
    • tweets by desisurvey
    • blog
    • acknowledgments
  • / galleries /
    • videos
    • image gallery
  • / for scientists /
    • data releases
    • instrument design
    • imaging data
    • target selection and survey validation
    • theory and simulations
    • other DESI science
    • key publications
    • all DESI papers
    • team login
    • request a DESI speaker
    • internal
  • / education & outreach /
    • meet a DESI member
    • blog
    • planetarium show
    • DESI high
    • interactive visualizations
    • DESI Merch

Marc Manera

October 6, 2025 by

Archives for October 2025

Marc Manera Profile picture

What is your position or role in the DESI project?
Over the years, I had different roles in the DESI project. For example, I was the co-chair of the Image Validation Task Force that validated the images that were used afterwards to target galaxies. In the last three years I was a member of the Education and Public Outreach Committee from which I am now stepping down. I am currently doing science in the Clustering, Clusters, and Cross-correlation working group.

Where were you born?
I was born in Barcelona.

Where do you live now?
I currently live in Barcelona. I was lucky to get a faculty position at a university in the city where I was born. I lived more than ten years abroad though, before coming back.

What do you do as part of DESI?
I am looking at gravitational redshifts. The light of the galaxies that live at or near the center of dark matter halos suffers a colour shift when it gets out of the halo due to the pull of gravity. This shift in colour is called gravitational redshift and could tell us a lot of information about the dark matter halos and about the validity of General Relativity. I am currently measuring gravitational redshifts from DESI galaxies.

What is the most interesting or exciting thing about your job?
The most exciting thing is being able to contribute to the advance of science, answering the most fundamental questions in cosmology and fundamental physics.

Any advice for an aspiring scientist?
Ask questions. Ask more questions. Follow the path of your curiosity. Work with other people to get your answers. I would also add that learning  to code is quite important. Being a scientist takes a lot of dedication and it usually requires moving cities a few times before settling in a place, but it is rewarding too.

What do you do for fun?
I play with my four year old son. I help a local boys and girls scouts group. I discuss theology with friends. I read fantasy novels.

If you weren’t a scientist, what would be your dream job?
My dream job is to be a scientist! I’m very fortunate because I have wanted to do what I am doing now since I was twelve. If I were not a scientist I would probably be a high school teacher, a philosopher or a theologian.

What excites/interests you most about DESI?
It is wonderful to work with so many people and ideas. DESI might have given the first serious hint that dark energy, the energy that causes the expansion of the universe, might not be constant over time. This is very exciting!

Filed Under: meet a DESI member

A slice of the Universe mapped by DESI data. The large-scale structure of the Universe is visible in the inset image. Credit: DESI Collaboration/DOE/KPNO/NOIRLab/NSF/AURA/C. Lamman

6 October 2025

Seshadri Nadathur (University of Portsmouth)

To coincide with the official publication, today in Physical Review D, of the first DESI papers on cosmology results from baryon acoustic oscillations from Data Release 2 (DR2), the DESI collaboration has also released the full set of cosmology chains and other results supporting the papers. This set of data products derived from the DR2 data is being released in advance of DR2 itself, and will allow researchers outside DESI to reproduce our results and explore new avenues.

The published “cosmology chains” contain valuable statistical information about the cosmological parameters and how well they are known. To infer the parameters, cosmologists often use methods that draw random samples from complex, multi-dimensional probability distributions. In the Markov Chain Monte Carlo (MCMC) method, a current set of randomly selected parameter values is used to generate the next random sample, resulting in a “chain” of sampled parameter values, a “cosmology chain”.   

The DR2 cosmology data released today are available from this webpage, and are based on the BAO results announced in March 2025 (see here for a guide to those results). They can also be accessed directly from the NERSC supercomputing facility. The dataset includes all the MCMC chains posterior sampling runs for cosmology inference, as well as information on the “best-fit” parameter values that maximize the posterior obtained through optimization. 

These data are being provided in advance of the full DR2 release in recognition of their very high significance to the cosmology community. When the full DR2 is made public in some months, these data will eventually form one of the “value-added catalogues” or VACs that accompany it.

Alongside this release, we have also released two new VACs supplementing the older Data Release 1 announced in March: these contain the corresponding cosmology chains and results based on the DR1 BAO cosmology papers from April 2024 (available here, see the paper guide here), and the DR1 full-shape cosmology papers from November 2024 (available here, see the paper guide here). Both of these new datasets are now included in the full list of DR1 VACs.

We invite interested scientists to explore these datasets, and hope that they prove to be useful for your research. In case of questions, please use the contact information provided on the landing pages of the dataset in question.



Filed Under: blog, feature on homepage

Primary Sidebar

Copyright © 2018 Dark Energy Spectroscopic Instrument [DESI]

  • / science /
    • science overview
    • cosmology and dark energy
    • redshifts and distance
    • mapping the universe
    • the DESI science mission
    • the DESI survey
    • imaging surveys
  • / instrument /
    • instrument overview
    • telescope
      • tohono o’odham
    • corrector
    • focal plane system
    • fiber system
    • spectrograph
    • instrument control system
    • data systems
    • bringing DESI to life
      • commissioning Instrument
      • protoDESI
  • / collaboration /
    • DESI team
    • DESI builders
    • collaborating institutions
    • sponsors
    • code of conduct
    • vendors
    • collaboration policies
  • / press /
    • announcements
    • in the news
    • press releases
    • tweets by desisurvey
    • blog
    • acknowledgments
  • / galleries /
    • videos
    • image gallery
  • / for scientists /
    • data releases
    • instrument design
    • imaging data
    • target selection and survey validation
    • theory and simulations
    • other DESI science
    • key publications
    • all DESI papers
    • team login
    • request a DESI speaker
    • internal
  • / education & outreach /
    • meet a DESI member
    • blog
    • planetarium show
    • DESI high
    • interactive visualizations
    • DESI Merch

Footer

TEAM LOGIN

twitter   instagram   facebook

Copyright © 2018 Dark Energy Spectroscopic Instrument [DESI]

Copyright © 2025 · Parallax Pro DESI on Genesis Framework · WordPress · Log in