Rubin Science Assembly
Thu Mar 20, 2025
Andrés A. Plazas Malagón Shenming Fu
Science Preparation: Dark Energy and Cosmology
Reminder to turn on recording!
Rubin Science Assembly
Today’s Agenda
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9:00 am : Announcements (~ 5 min)
9:05 a.m: Cosmology with LSST (~5 min).
9:10 a.m: Data Products (~10 min).
9:20 a.m: Data Access Demo (~30 min). (10+10 min notebook, 10 min portal)
9:50 a.m: Q & A (~10 min).
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Announcements
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Announcements
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Save the date: Rubin Community Workshop 2025
Upcoming Rubin Science Assemblies (see next slide)
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Announcements
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Assemblies will still be announced in the Community Forum and in the Discovery Alliance Slack space.
March - May will feature a special series of science preparation seminars.
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LINCC Frameworks Office Hours
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LINCC Frameworks mission is to enable scientists by developing scalable and productionised software/algorithms in collaboration with broader community.
LINCC Frameworks Projects
Office Hours provides users an opportunity to learn about or get support for LINCC Frameworks software.
When: Most Thursdays 1pm ET / 10am PT / 7pm CET (see LF Calendar)
Where: Zoom (zoom link)
You can also submit questions via the #lincc-frameworks-qa slack channel and sign up for the LINCC mailing list for more updates (instructions).
Website
Introduction to the Users Committee
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The Rubin Users Committee is charged with:
Charge: rdo-051.lsst.io
Website: lsst.org/scientists/users-committee
Reports: available in the Rubin Community Forum (community.lsst.org/tag/users-committee)
Meetings: two formal meetings per year, which always start with an open community listening session
Contact: via email to RubinObs-Users-Committee@lists.lsst.org or via the Rubin Community Forum
(go to Community.lsst.org and send a direct message to the @Users-Committee group)
Feedback: use the Google form at forms.gle/km4VS2r2uYrvJ2w58
The Rubin Users Committee looks forward to hearing from the Rubin science community.
Igor Andreoni Dominique Boutigny Alejandra Muñoz Arancibia Alessandra Corsi
Anupreeta More Vincenzo Petrecca Vicki Sarajedini Matthew Holman
Darryl Seligman Anja von der Linden Matthew P. Wiesner Michael Wood-Vasey
Vera C. Rubin Observatory | Users Committee | 2024-2025
New here? Welcome!
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Get a Rubin Science Platform (RSP) account: rsp.lsst.io
Simulated data is available as part of Data Preview 0 (DP0)
Find general information for scientists: rubinobservatory.org/for-scientists
NEW!
Rubin Science Assembly
Introduction to the Users Committee
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The Rubin Users Committee is charged with:
Charge: rdo-051.lsst.io
Website: lsst.org/scientists/users-committee
Reports: available in the Rubin Community Forum (community.lsst.org/tag/users-committee)
Meetings: two formal meetings per year, which always start with an open community listening session
Contact: via email to RubinObs-Users-Committee@lists.lsst.org or via the Rubin Community Forum
(go to Community.lsst.org and send a direct message to the @Users-Committee group)
Feedback: use the Google form at forms.gle/km4VS2r2uYrvJ2w58
The Rubin Users Committee looks forward to hearing from the Rubin science community.
Igor Andreoni Dominique Boutigny Alejandra Muñoz Arancibia Alessandra Corsi
Anupreeta More Vincenzo Petrecca Vicki Sarajedini Matthew Holman
Darryl Seligman Anja von der Linden Matthew P. Wiesner Michael Wood-Vasey
Vera C. Rubin Observatory | Users Committee | 2024-2025
New here? Welcome!
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Get a Rubin Science Platform (RSP) account: rsp.lsst.io
Simulated data is available as part of Data Preview 0 (DP0)
Find general information for scientists: rubinobservatory.org/for-scientists
NEW!
Rubin Science Assembly
Instructions to set up for the hands-on tutorial
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These will work for those who already have an account in the Rubin Science Platform at data.lsst.cloud.
No account yet? Visit rsp.lsst.io to get started. Watch the tutorial today, and work through it yourself later.
Brief: In one browser tab, enter the Notebook Aspect, choosing the recommended image and a medium server. Git clone this repo: github.com/rubin-dp0/dp1-sci-prep-seminars.
Step-by-step:
git clone https://github.com/rubin-dp0/dp1-sci-prep-seminars.git
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* You will see this when you open the notebook for the first time.
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LSST and Cosmology
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Lambda-CDM, Standard Model
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Figs from NASA/WMAP/Wikipedia
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LSST and Cosmology
Geometry of the Universe
Angular diameter distance: standard ruler (BAO), SL
Luminosity distance: standard candle (SNIa)
Matter in the Universe
Power spectrum: WL
Growth of structure
Halo mass function: galaxy clusters
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Also joint analysis! e.g., 3x2 cross correlations – shear-shear, (number) density-density, and shear-density (both cosmic shear and clustering)
BAO: Baryon Acoustic Oscillation
SL: Strong Lensing
SN Ia: Type Ia Supernovae
WL: Weak Lensing
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Our scientific aim: Exploring the physics of the Dark Universe
Dark energy, dark matter, neutrinos and signatures of inflation
Our approach: Combining (at least) five cosmological probes:
visit https://lsstdesc.org/ for more details
For DESC membership
(LSST Data Rights required),
apply here
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The Rubin LSST Dark Energy Experiment
Rubin is the “LSST Facility” that provides data products for cosmology analysis by the DESC
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Facility: Rubin Observatory
Collaboration: LSST DESC
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The DESC will make high accuracy measurements of fundamental cosmological parameters from LSST data
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The DESC requirement that Rubin LSST be a “Stage IV” Dark Energy experiment will drive development of improved photo-z, deblending, PSF modeling, transient classification etc - for the benefit of all
FoM = 142
LSST DESC SRD v1
Y1
Y10
FoM = 504
LSST DESC SRD v1
LSST data only; synergy with other instruments (e.g., Stage III) can give even tighter constraints. “w” is the ratio of the pressure to the energy density (the equation-of-state parameter). Typically w=-1 for dark energy as a cosmological constant. A widely used evolving dark energy model is w = w_0 + (1 − a)*w_a. See Frieman+08 for a review.
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Data Products
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Data Products
https://rubinobservatory.org/for-scientists/data-products/planned-data-products
Some essential pipeline steps for cosmology: (static science)
*Time domain science will be covered in a future session (e.g., SN Ia cosmology).
**Cell-based coadds: coadds of images in small (few arcsecond) cells, in which only input images that fully contain a cell are included. This helps mitigate problems with PSF discontinuities that are present in traditional coadds.
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Early Science Data
DP0: Simulation data (cosmology: DC2 from DESC, already available)
DP1: ComCam (collected and being processed)
DP2: LSSTCam Science Validation – 100deg2 @ 10yr depth (ugrizy) + 1000deg2 @ 1 year depth (griz) [SITCOMTN-005]
DR1: LSST survey data (6 months)
…
More details in the next slide
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Early Science Data Products (RTN-011, Table 1)
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DP: Data Preview, DR: Data Release, DRP: Data Release Pipeline, AP/PP: Alert Production (60sec)/Prompt Products (24hr), SSP: Solar System Processing. Data Products Definition Document
Time domain
current
soon
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Connection with Cosmo-Probes: Examples
*ShearObject is not available in DP1, may be in DP2, but will be in DR1 and later.
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| WL (cosmic shear) | BAO (clustering) | Clusters | Ia SNe | SL | …… |
Object Table | ✅ | ✅ | ✅ | | ✅ | |
Photo-z | ✅ | ✅ | ✅ | (✅ or spec-z) | | |
DIA source | | | | ✅ | (✅ time delay) | |
ShearObject | ✅ | | ✅ | | (✅) | |
…… | | | | | | |
Probe
Data
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Data Access Demo
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Portal & Notebooks
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Note: RSP is open to all data right holders. DESC typically uses NERSC to analyze data in large scale. New DESC members can first get familiar with the LSST data at the RSP.
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Notebook examples on Cosmology
We use the Object Table.
(We will share the screen. See details in the Github page. You can git clone it in the Jupyter Lab terminal.)
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Notebook part 1: WL, PSF
PSF size and shape
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Notebook part 2: Galaxy Cluster
Red sequence and lensing profile
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Portal example
Cluster galaxy magnitude and color (link). To save time, we just present the screenshots.
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Making a cone search for high quality objects in the DP02 Object Catalog
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Refine the cut by setting a smaller radial_offset (<0.03)
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Add new plots
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Note heatmap won’t work for too few data points.
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Red sequence
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Q & A
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Backup Slides
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LSST Data Products
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template
new
difference
Difference Image Analysis (DIA)
In 60s, raw images are processed, a template is subtracted, and difference-image sources are detected, associated, characterized, and…
…distributed as alerts to brokers, where they can be rapidly analyzed by users.
In 24h, the Prompt Products Database (PPDB) is updated with the DIA data products.
Yearly data releases include DIA, coadded images, and catalogs for all data to date.
The Prompt (24h) and Data Release (annual) data products will be available for users to analyze via the Rubin Science Platform.
raw data
Rubin Science Assembly