Survey Strategy III:

Domain-Specific Cadence Optimization Discussions

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Session Organizers: Sara (Rosaria) Bonito (Chair); Rachel Street, Will Clarkson, Federica Bianco, Andjelka Kovacevic, Dragana Ilic, Maribel Carnerero, Ilaria Musella

SCOC and OpSims experts: Peter Yoachim, Knut Olsen, Jay Strader

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Sara (Rosaria) Bonito - INAF - Observatory of Palermo (Italy) rosaria.bonito@inaf.it

Vera C. Rubin Observatory | Project & Community Workshop | 9-13 August 2021

Acronyms & Glossary

Friendly reminders

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Vera C. Rubin Observatory | Project & Community Workshop | 9-13 August 2021

Acronyms & Glossary

Friendly reminders

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Vera C. Rubin Observatory | Project & Community Workshop | 9-13 August 2021

Acronyms & Glossary

Logistics

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• Session Chair: Sara Bonito
• Note takers: Rachel Street & Will Clarkson

(but anyone can edit: https://docs.google.com/document/d/1ybOVJ6oWEkgng7cn0XtRGK1dGWohdYjR1xWdkpqaoqU/edit?usp=sharing&urp=gmail_link

• Zoom chat/Slack channel moderators: Andjelka Kovacevic & Dragana Ilic; Slack channel preferred (#multi-slot-survey-strategy: https://rubin2021pcw.slack.com/archives/C029UFTNP7W); raise hand in Zoom to join the discussion
• Time keeper/moderator of the “flash talks”: Ilaria Musella
• Slides (anyone can continue contributing feedback for the SCOC meeting in Nov. 2021): https://docs.google.com/presentation/d/1kVSdClzcM1EJ3zWhSg6Aza-1Nf_AdjPwme5HaL-RDR8/edit#slide=id.ge6d80895ae_3_235

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Sara (Rosaria) Bonito - INAF - Observatory of Palermo (Italy)

Sara (Rosaria) Bonito - INAF - Observatory of Palermo (Italy) rosaria.bonito@inaf.it

Vera C. Rubin Observatory | Project & Community Workshop | 9-13 August 2021

Acronyms & Glossary

Logistics

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In this session, we will focus on topics of mutual interest to multiple Science Collaborations. The goal is to encourage information sharing and joint work between the Collaborations, including work done after the Cadence Note deadline, the results of the SCOC review, and the next steps needed. Please contact the session chair if you're interested in contributing content to this session and/or facilitating one of the topical breakout rooms (or reply to this post in the Community Forum: ls.st/clo5691). Multiple breakout rooms can also be organized by science topic to enable discussion of survey strategy work.

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Sara (Rosaria) Bonito - INAF - Observatory of Palermo (Italy)

Sara (Rosaria) Bonito - INAF - Observatory of Palermo (Italy) rosaria.bonito@inaf.it

Vera C. Rubin Observatory | Project & Community Workshop | 9-13 August 2021

Acronyms & Glossary

Work done before PCW in 2020 - 2021

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Transients & Variable Stars (TVS) & Stars, Milky Way, and Local Volume (SMWLV) Task Forces (2020 - 2021): organizers

• TVS 2020: Rachel Street, Rosanne DiStefano, Federica Bianco, Sara Bonito
• SMWLV 2020 - 2021: Will Clarkson (Chair), Sara Bonito (TVS liaison), Annalisa Calamida, John Gizis, Dave Monet, Knut Olsen (SCOC liaison), Mike Rich (SMWLV commissioning liaison), Jay Strader (SCOC liaison), Nic Walton
• TVS 2021: Rachel Street (Chair), Rosanne DiStefano, Claudia Raiteri, Igor Andreoni, Andjelka Kovacevic, Michael William Coughlin, Robert Szabo, Ilya Mandel, Ilaria Musella, Sara Bonito, Silvio Leccia, Dragana Ilic, Giulia De Somma, Marcella Marconi, Maribel Carnerero

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Sara (Rosaria) Bonito - INAF - Observatory of Palermo (Italy)

Sara (Rosaria) Bonito - INAF - Observatory of Palermo (Italy) rosaria.bonito@inaf.it

Vera C. Rubin Observatory | Project & Community Workshop | 9-13 August 2021

Acronyms & Glossary

Time-Domain Science Metrics [Status at Hackathon August 2020]

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Vera C. Rubin Observatory | Project & Community Workshop | 9-13 August 2021

Acronyms & Glossary

Survey Strategy Task Forces

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Several science collaborations have formed working groups/task forces to assess OpSims

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TVS & SMWLV Task Forces coordinating work on overlapping science interests

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Substantial progress with metric developments since 2020 hackathon and for Cadence Notes

• Includes new metrics

SCs are keen to working with the MAF team & SCOC to integrate this work into the survey cadence optimization

Vera C. Rubin Observatory | Project & Community Workshop | 9-13 August 2021

Acronyms & Glossary

Contributors to this Session (Thank you!)

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(~80 % of submitted Cadence Notes)

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Hernitschek & Stassun Carlin et al. Lochner et al. / DESC OSWG

Musella et al. Gizis Clarkson et al. a

Prisinzano & Bonito et al. Tisanic & Palaversa Clarkson et al. b

Blaineau et al. Yu et al. Olsen et al.

Moniez et al. Anguita et al.

Figuera Jaimes et al. Frohmaier et al.

Abrams et al.

Bonito & Venuti et al. Li et al.

Kovacevic et al. Corrick et al.

Raiteri et al. Awan et al.

Assef et al. Inno et al.

Graham et al.

Andreoni et al. Cuillandre et al.

van Velzen et al. Bellm et al.

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Sara (Rosaria) Bonito - INAF - Observatory of Palermo (Italy)

Sara (Rosaria) Bonito - INAF - Observatory of Palermo (Italy) rosaria.bonito@inaf.it

Vera C. Rubin Observatory | Project & Community Workshop | 9-13 August 2021

Acronyms & Glossary

Survey Strategy III: Domain-Specific Cadence Optimization Discussions

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Session Agenda

• 5 min: Introduction (Sara Bonito)
• 10 min: SC submissions, an overview (Federica Bianco)
• 20 min: Flash talks by PIs/co-Is of Cadence Notes, grouped by topics (2 minutes each)
• 20 min: discussion and questions
• 5 min: wrap-up

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Sara (Rosaria) Bonito - INAF - Observatory of Palermo (Italy)

Sara (Rosaria) Bonito - INAF - Observatory of Palermo (Italy) rosaria.bonito@inaf.it

Vera C. Rubin Observatory | Project & Community Workshop | 9-13 August 2021

Acronyms & Glossary

FLASH TALKS

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Collected Topics (speaker)

SC Topics (speaker)

• Time domain science in the Galactic Plane and Magellanic Clouds (Rachel Street)
• AGN & Blazars (Andjelka Kovacevic)
• Supernovae, Kilonovae & TDE (Igor Andreoni)
• Milky Way and Local Volume (Jeff Carlin)
• Data Analysis (Weixiang Yu)
• Anomalies and True Novelties (Xiaolong Li)

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• Strong Lensing (Timo Anguita)
• Galaxies (Benne Holwerda)
• TiDES Extragalactic Survey (Jon Carrick)
• Dark Energy (Humna Awan)
• Solar System (Laura Inno)

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Sara (Rosaria) Bonito - INAF - Observatory of Palermo (Italy)

Sara (Rosaria) Bonito - INAF - Observatory of Palermo (Italy)

Sara (Rosaria) Bonito - INAF - Observatory of Palermo (Italy) rosaria.bonito@inaf.it

Vera C. Rubin Observatory | Project & Community Workshop | 9-13 August 2021

Acronyms & Glossary

FEDERICA BIANCO

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Vera C. Rubin Observatory | Project & Community Workshop | 9-13 August 2021

Acronyms & Glossary

Survey Strategy III: Domain-Specific Cadence Optimization Discussions

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three phases of community input

Federica Bianco fbianco@udel.edu

Vera C. Rubin Observatory | Project & Community Workshop | 9-13 August 2021

Acronyms & Glossary

Survey Strategy III: Domain-Specific Cadence Optimization Discussions

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Federica Bianco fbianco@udel.edu

CADENCE NOTES

Vera C. Rubin Observatory | Project & Community Workshop | 9-13 August 2021

Acronyms & Glossary

Survey Strategy III: Domain-Specific Cadence Optimization Discussions

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Federica Bianco fbianco@udel.edu

CADENCE NOTES

Vera C. Rubin Observatory | Project & Community Workshop | 9-13 August 2021

Acronyms & Glossary

Survey Strategy III: Domain-Specific Cadence Optimization Discussions

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Federica Bianco fbianco@udel.edu

CADENCE NOTES

Vera C. Rubin Observatory | Project & Community Workshop | 9-13 August 2021

Acronyms & Glossary

Survey Strategy III: Domain-Specific Cadence Optimization Discussions

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Federica Bianco fbianco@udel.edu

CADENCE NOTES

Vera C. Rubin Observatory | Project & Community Workshop | 9-13 August 2021

Acronyms & Glossary

Survey Strategy III: Domain-Specific Cadence Optimization Discussions

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CADENCE NOTES

Federica Bianco fbianco@udel.edu

Vera C. Rubin Observatory | Project & Community Workshop | 9-13 August 2021

Acronyms & Glossary

Survey Strategy III: Domain-Specific Cadence Optimization Discussions

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http://fbb.space/LSSTWP/WPbyfirstAuthor.html

WHITE PAPERS

Federica Bianco fbianco@udel.edu

Vera C. Rubin Observatory | Project & Community Workshop | 9-13 August 2021

Acronyms & Glossary

Survey Strategy III: Domain-Specific Cadence Optimization Discussions

COSEP (2015-2017)

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Federica Bianco fbianco@udel.edu

https://github.com/LSSTScienceCollaborations/ObservingStrategy

Vera C. Rubin Observatory | Project & Community Workshop | 9-13 August 2021

Acronyms & Glossary

Survey Strategy III: Domain-Specific Cadence Optimization Discussions

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It is important to acknowledge that people from all SCs have put a tremendous amount of work into this for a very long time! ALL volunteering their work.

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TASK Forces: TVS, SMWLV, Galaxies, DESC all have a task force or working group.

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Meetings: for example, TVS 2018 - TVS-SMWLV joint meeting 2019 - SC hackathon 2020 (before the PCW) - biweekly SMWLV hackaday (I only remember the TVS ones but I know other SCs did it too!)

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Federica Bianco fbianco@udel.edu

Vera C. Rubin Observatory | Project & Community Workshop | 9-13 August 2021

Acronyms & Glossary

Survey Strategy III: Domain-Specific Cadence Optimization Discussions

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It is important to acknowledge that people from all SCs have put a tremendous amount of work into this for a very long time! ALL volunteering their work.

• DESC and SSSC maps have been integrated into the SCOC evaluation framework

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Federica Bianco fbianco@udel.edu

Vera C. Rubin Observatory | Project & Community Workshop | 9-13 August 2021

Acronyms & Glossary

Survey Strategy III: Domain-Specific Cadence Optimization Discussions

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It is important to acknowledge that people from all SCs have put a tremendous amount of work into this for a very long time! ALL volunteering their work.

• DESC and SSSC maps have been integrated into the SCOC evaluation framework
• MAFs for other science cases have not been integrated at the same pace/ as succesfully

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e.g. “DESC - static science (3x2pt FoM, effective area) and transient (SN and SLSN, KNe)”

Federica Bianco fbianco@udel.edu

It would be very helpful to have a compiles list of metrics for each SC

Vera C. Rubin Observatory | Project & Community Workshop | 9-13 August 2021

Acronyms & Glossary

Survey Strategy III: Domain-Specific Cadence Optimization Discussions

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It is important to acknowledge that people from all SCs have put a tremendous amount of work into this for a very long time! ALL volunteering their work.

• DESC and SSSC maps have been integrated into the SCOC evaluation framework
• MAFs for other science cases have not been integrated at the same pace/ as succesfully

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Those SCs have adopted MAF early on - the other SCs have made a lot of progress over time tho!

• early on: installation and software resilience
• middle of the road: sharing knowledge on MAF was difficult. We invited speakers to meetings and shared the videos but adoption was slow
• => 2020 - ANG SC set up sciserve and demo notebooks to run on it, NOIRlab enables the portal
• “metric limbo”: many metrics were created and submitted but there were not enough resources to work with each individual to unpack, optimize, validate their MAF
• domain expertise in the metric team are limited by the tiny number of people in the team

Federica Bianco fbianco@udel.edu

Vera C. Rubin Observatory | Project & Community Workshop | 9-13 August 2021

Acronyms & Glossary

Survey Strategy III: Domain-Specific Cadence Optimization Discussions

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Federica Bianco fbianco@udel.edu

It is important to acknowledge that people from all SCs have put a tremendous amount of work into this for a very long time! ALL volunteering their work.

• DESC and SSSC maps have been integrated into the SCOC evaluation framework
• MAFs for other science cases have not been integrated at the same pace/ as succesfully

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Those SCs have adopted MAF early on - the other SCs have made a lot of progress over time tho!

• early on: installation and software resilience
• middle of the road: sharing knowledge on MAF was difficult. We invited speakers to meetings and shared the videos but adoption was slow
• => 2020 - ANG SC set up sciserve and demo notebooks to run on it, NOIRlab enables the portal
• “metric limbo”: many metrics were created and submitted but there were not enough resources to work with each individual to unpack, optimize, validate their MAF
• domain expertise in the metric team are limited by the tiny number of people in the team

Vera C. Rubin Observatory | Project & Community Workshop | 9-13 August 2021

Acronyms & Glossary

Survey Strategy III: Domain-Specific Cadence Optimization Discussions

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propritize integration of existing metrics that never made it in

Federica Bianco fbianco@udel.edu

It is important to acknowledge that people from all SCs have put a tremendous amount of work into this for a very long time! ALL volunteering their work.

• DESC and SSSC maps have been integrated into the SCOC evaluation framework
• MAFs for other science cases have not been integrated at the same pace/ as succesfully

​

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Those SCs have adopted MAF early on - the other SCs have made a lot of progress over time tho!

• early on: installation and software resilience
• middle of the road: sharing knowledge on MAF was difficult. We invited speakers to meetings and shared the videos but adoption was slow
• => 2020 - ANG SC set up sciserve and demo notebooks to run on it, NOIRlab enables the portal
• “metric limbo”: many metrics were created and submitted but there were not enough resources to work with each individual to unpack, optimize, validate their MAF
• domain expertise in the metric team are limited by the tiny number of people in the team

Vera C. Rubin Observatory | Project & Community Workshop | 9-13 August 2021

Acronyms & Glossary

Survey Strategy III: Domain-Specific Cadence Optimization Discussions

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NOT ALL SCs will provide a consensus metric - the aggregation is an SCOC responsibility

Federica Bianco fbianco@udel.edu

It is important to acknowledge that people from all SCs have put a tremendous amount of work into this for a very long time! ALL volunteering their work.

• DESC and SSSC maps have been integrated into the SCOC evaluation framework
• MAFs for other science cases have not been integrated at the same pace/ as succesfully

​

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Those SCs have adopted MAF early on - the other SCs have made a lot of progress over time tho!

• early on: installation and software resilience
• middle of the road: sharing knowledge on MAF was difficult. We invited speakers to meetings and shared the videos but adoption was slow
• => 2020 - ANG SC set up sciserve and demo notebooks to run on it, NOIRlab enables the portal
• “metric limbo”: many metrics were created and submitted but there were not enough resources to work with each individual to unpack, optimize, validate their MAF
• domain expertise in the metric team are limited by the tiny number of people in the team

Vera C. Rubin Observatory | Project & Community Workshop | 9-13 August 2021

Acronyms & Glossary

Survey Strategy III: Domain-Specific Cadence Optimization Discussions

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Not all science domains can be “simulated” reliably to create an N_something metric

Federica Bianco fbianco@udel.edu

It is important to acknowledge that people from all SCs have put a tremendous amount of work into this for a very long time! ALL volunteering their work.

• DESC and SSSC maps have been integrated into the SCOC evaluation framework
• MAFs for other science cases have not been integrated at the same pace/ as succesfully

​

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Those SCs have adopted MAF early on - the other SCs have made a lot of progress over time tho!

• early on: installation and software resilience
• middle of the road: sharing knowledge on MAF was difficult. We invited speakers to meetings and shared the videos but adoption was slow
• => 2020 - ANG SC set up sciserve and demo notebooks to run on it, NOIRlab enables the portal
• “metric limbo”: many metrics were created and submitted but there were not enough resources to work with each individual to unpack, optimize, validate their MAF
• domain expertise in the metric team are limited by the tiny number of people in the team

Vera C. Rubin Observatory | Project & Community Workshop | 9-13 August 2021

Acronyms & Glossary

Survey Strategy III: Domain-Specific Cadence Optimization Discussions

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List of all SC metrics to be shared with the SCOC

Federica Bianco fbianco@udel.edu

It is important to acknowledge that people from all SCs have put a tremendous amount of work into this for a very long time! ALL volunteering their work.

• DESC and SSSC maps have been integrated into the SCOC evaluation framework
• MAFs for other science cases have not been integrated at the same pace/ as succesfully

​

​

Those SCs have adopted MAF early on - the other SCs have made a lot of progress over time tho!

• early on: installation and software resilience
• middle of the road: sharing knowledge on MAF was difficult. We invited speakers to meetings and shared the videos but adoption was slow
• => 2020 - ANG SC set up sciserve and demo notebooks to run on it, NOIRlab enables the portal
• “metric limbo”: many metrics were created and submitted but there were not enough resources to work with each individual to unpack, optimize, validate their MAF
• domain expertise in the metric team are limited by the tiny number of people in the team

Vera C. Rubin Observatory | Project & Community Workshop | 9-13 August 2021

Acronyms & Glossary

Survey Strategy III: Domain-Specific Cadence Optimization Discussions

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Monthly meeting SCOC+SC?

Federica Bianco fbianco@udel.edu

It is important to acknowledge that people from all SCs have put a tremendous amount of work into this for a very long time! ALL volunteering their work.

• DESC and SSSC maps have been integrated into the SCOC evaluation framework
• MAFs for other science cases have not been integrated at the same pace/ as succesfully

​

​

Those SCs have adopted MAF early on - the other SCs have made a lot of progress over time tho!

• early on: installation and software resilience
• middle of the road: sharing knowledge on MAF was difficult. We invited speakers to meetings and shared the videos but adoption was slow
• => 2020 - ANG SC set up sciserve and demo notebooks to run on it, NOIRlab enables the portal
• “metric limbo”: many metrics were created and submitted but there were not enough resources to work with each individual to unpack, optimize, validate their MAF
• domain expertise in the metric team are limited by the tiny number of people in the team

Vera C. Rubin Observatory | Project & Community Workshop | 9-13 August 2021

Acronyms & Glossary

PART 1

FLASH TALKS:

1 slide/topics in Cadence Notes

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Sara (Rosaria) Bonito - INAF - Observatory of Palermo (Italy)

Collected Topics

SC Topics

• Time domain science in the Galactic Plane and Magellanic Clouds
• AGN & Blazars
• Supernovae, Kilonovae & TDE
• Milky Way and Local Volume
• Data Analysis
• Anomalies and True Novelties

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• Strong Lensing
• Galaxies
• TiDES Extragalactic Survey
• Dark Energy
• Solar System

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FLASH TALKS

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Collected Topics (speaker)

SC Topics (speaker)

• Time domain science in the Galactic Plane and Magellanic Clouds (Rachel Street)
• AGN & Blazars (Andjelka Kovacevic)
• Supernovae, Kilonovae & TDE (Igor Andreoni)
• Milky Way and Local Volume (Jeff Carlin)
• Data Analysis (Weixiang Yu)
• Anomalies and True Novelties (Xiaolong Li)

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• Strong Lensing (Timo Anguita)
• Galaxies (Benne Holwerda)
• TiDES Extragalactic Survey (Jon Carrick)
• Dark Energy (Humna Awan)
• Solar System (Laura Inno)

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Sara (Rosaria) Bonito - INAF - Observatory of Palermo (Italy)

Sara (Rosaria) Bonito - INAF - Observatory of Palermo (Italy)

Sara (Rosaria) Bonito - INAF - Observatory of Palermo (Italy) rosaria.bonito@inaf.it

Vera C. Rubin Observatory | Project & Community Workshop | 9-13 August 2021

Acronyms & Glossary

Time-Domain Science in the Galactic Plane and Magellanic Clouds

Galactic Plane/Magellanic Clouds Footprint and Variability Timescales FoM

Contributors: Rachel Street, TVS Microlensing and Stellar Variability Groups

Combined footprints from White Papers → map of priority regions

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Defined simple variability timescale metrics in 4 categories:

<10d

10-100d

100-365d

>365d

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Outstanding issues:

• Does not capture need for colors
• Include series of fields space across the Plane?

Attempting to represent range of galactic stellar variability with combined Figure of Merit

AGN&Blazars - Map:AGN(LC,SED,cardinality)⟼ time&spatial scales (delay, periodicity, photo-z,..)

time and spatial scales increase

time scales ~ a few days

SMBH+jets

time scale >10d-months- yr

accr.disk, BLR,binary SMBH-nHz GW

cosmic time

scale 1.7 ⪅z ⪅3.0 ≈QSOs activity peaks and Lyα break at 912 ̊A

-->improve quality of photo-z; WFD with larger footprints to find high-z and extremely luminous QSO

Supernovae, Kilonovae, Tidal Disruption Events

Supernovae, Kilonovae, Tidal Disruption Events

Outstanding issues:

• How will a rolling cadence be implemented? Can the algorithm be further improved?
• Synergy with UV observatories in space (e.g., ULTRASAT)

Metrics were developed to inject & recover transients in simulated cadences

TDE + Supernovae:

• The more blue filter coverage, the better (for SNe: deeper u-band)

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Kilonovae:

• The more red filter coverage, the better
• 1 x 30s exposures are much preferred to 2 x 15s exposures

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Kilonovae + Supernovae:

• Same-night triplets can be beneficial
• Rolling cadences could be preferred
• High cadence should be kept or increased, not decreased

Milky Way and Local Volume Science

Milky Way and Local Volume Science

Dwarf satellites in the Local Volume:

• Deeper g-band is better; single snap in g-band helps (see also Bell+2018 Cadence White Paper)
• Wider and deeper WFD footprint
• Cadences optimized for good seeing

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Saturation and bright objects:

• Relatively unexplored in OpSims to-date
• Prefer 5 x 2s per filter per field per year

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Bulge stellar populations:

• u-band depth required; uniformity between grizy preferred
• Prefer WFD extended to the inner plane
• Good seeing preferred
• Generally prefer most observations early to build depth in the CMD�

Brown dwarf astrometry:

• Prefers widest coverage in WFD (especially in red -- z, y -- filters)
• Single snaps (1 x 30s exposures) preferred to 2 x 15s exposures
• Twilight observations needed for parallaxes

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Magellanic Clouds:

• Wider WFD (extended to south Galactic cap)
• Deeper g-band

Data Analysis

Simulations of multiband Lomb-Scargle-derived variable star periods

Contributors: K. Tisanić, L. Palaversa

Goal: Given a predefined cadence with a fixed number of observations, what is the worst-case scenario constraint on the period uncertainty of a variable star? The goal of this analysis is to determine the minimum number of observations required to obtain the correct period of a pulsating variable star.

Methods: The procedure consists of two stages: building up a library of ``synthetic'' light curves and simulations of period determination through variation of the number of observations drawn from the synthetic light curves. We use a cadence logarithmic in time to cover both larger and smaller periods.

We simulated the distribution of observations between the g, r, and i bands as well as the distribution of magnitude errors.

Data and Software: A sample of the Gaia DR2+ ZTF DR3 cross-match, Lomb-Scargle periods determined using gatspy.

Metrics: Standard deviation of the simulated periods and the logarithm of the absolute error of the synthetic lightcurve period (P_ZTF) and the simulated periods

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Conclusions: We find that there is no significant difference in the behavior of the 16th, 50th, 84th, and 99th percentiles of the R statistic between different types of variable stars, except for the 99th percentiles of type II Cepheids and Miras. We conclude that for simulated variable star types, there is a 50% chance of reaching a 0.1% relative error in period for 10 measurements with a logarithmically-spaced cadence, and 99 % chance of reaching 1% relative error for 15-20 measurements, except for type II Cepheids and Miras, which reach this threshold at 30 measurements.

Differential Chromatic Refraction (DCR)

Weixiang Yu & Gordon Richards on behalf of the AGN SC

Redshift

Goal: Minimize sigma_m in u and g, where sigma_m is jointly determined by single-visit depth, number of visits and maximum airmass.

Results:

1. Favor u-long if N is kept unchanged
2. dcr/dm_heavy family are also preferred
3. No preference on rolling

Open Questions: If/what/how DCR information will be saved/reported?

Anomalies and True Novelties

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Preparing to discover the unknown with Rubin LSST

Contributors: Xiaolong Li, Fabio Ragosta, Federica Bianco, Will Clarkson

• Flux change
• Color
• Depth
• Footprint
• Proper Motion

Goal: explore the ability of strategies for discovering “true novelties”

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Method: evaluate the completeness of the survey in the phase space composed of

Preparing to discover the unknown with Rubin LSST

Outcomes: Families that include short observations will improve the capability to collect color and shape information for transients light curve, moreover we highlighted that the top performing OpSims in each family have the potential of being implemented in a way that is favorable to the discovery of true-novelties, with the exception of specialized surveys.

The arrows point to the opsims showed in the radar plot

“Static” Strong Lensing Science

Aims:

• Wide area → Increases sample size
• Early “all sky reference image” with excellent seeing and sensitivity, especially in the g-band → Identify/isolate lensed sources

Analysis:

• Good blue image quality simulations have minimal impact on overall depth
• Minimal impact on other metrics by rewarding blue image quality first year only

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Contributors: Timo Anguita, Aprajita Verma & Thomas Collett on behalf of the SLSC

First year median per visit seeing (left) and median best epoch seeing per visit (right) for large (filterdist family) and baseline like (goodseeing family) area simulations.

The Time-Domain Extragalactic Survey (TiDES)

• 250,000 fibre-hours on 4MOST for spectroscopic follow up of SNe, their host-galaxies, and AGN reverberation mapping.
• Largest spectroscopic follow-up facility of LSST transients
• Most precise measurement of cosmological parameters from type Ia supernovae.
• Require well sampled light curves with good filter coverage.
• Share conclusions with DESC cadence note for WFD and DDF cadences.
• 4MOST dec < +5, would favour LSST match this footprint.
• AGN in DDF, keep dither within 4MOST FoV (~4°)
• Would like to see more rolling cadence simulations. Strong transient case to pair with 4MOST.

Contributors: C. Frohmaier (c.frohmaier@soton.ac.uk) on behalf of the TiDES collaboration

Galaxies Science Collaboration Cadence Note

Priorities:

1. Uniform high-quality in static sky co-adds
2. Mitigate scattered light
• Explore strategies during commissioning
3. Achieve a uniform base level of excellent seeing in one (or two bands) early in the survey (first year or two)
• Suggested FOM rewards both good seeing and uniformity:
• FOMseeing = mean(0.7/θ)²/(1 + σ²(0.7/θ))
4. Obtain full depth on one deep-drilling field early in the survey
5. Extend the main survey to northern areas of low extinction
• Improves overlap with Euclid with only a modest impact on overall depth
6. Include the Virgo Cluster as a mini-survey
7. Favor fewer, longer exposures for u-band with at least a few visits per field in good weather at low airmass

https://docushare.lsst.org/docushare/dsweb/Get/Document-37637/Galaxies_Summary.pdf

DESC Response to Cadence Notes Call

(see note here)

Current focus on probes: LSS, WL, SN, SL, KN; all depend on photo-zs.

• Developed several cosmology-related metrics to analyse observing strategy
• WFD:
• Recommend defining extragalactic part of the footprint using dust extinction limits.
• Internal trade-off between cadence and area. Important not to reduce number of extragalactic visits; rolling is a solution.
• DDFs: rolling + extra time

On behalf of DESC Observing Strategy Working Group

Accompanying journal article (submitted for focus issue)

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LSS = Large Scale Structure; WL = Weak Lensing, SN = Supernovae, SL = Strong Lensing, KN = Kilonovae

summary metric combining statistics (WL, LSS, SN) and systematics (WL, photo-z)

Ranking of the simulations

1

CONTRIBUTED SLIDES

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52

Vera C. Rubin Observatory | Project & Community Workshop | 9-13 August 2021

Acronyms & Glossary

Young stellar objects and their variability

Use of the light curve to discriminate different short-term processes at work in young stellar objects with accretion/ejection

Goal: a week long run of 10 hours per night with observations every 30 min each year on Carina Nebula with g, r, i (u) filters

Metrics:

• TransientAsciiMetric.ipynb
• OpSim db: carina_v1.7_10yrs

Challenges:

• High number of points in ach filter requires

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Sara Bonito & Laura Venuti, Guarcello, Yoachim, Prisinzano, Stassun, Giannini, Street, Clarkson, Mc Gehee, Bellm, Gizis, Hartigan

Examples of light curves and simulation on Rubin LSST sampling

Interested to join: TBD

Bonito & Venuti et al. 2021 (to be converted into an ApJS paper)

TWO METRICS ON AGN VARIABILITY OBSERVABLES

AGN variability observables (time-lags, periodicities, and structure-function) are essential for constraining AGN models, empirical relations important for cosmology and detecting nano-Hz GW sources.

Goal: To quantify and test individual Opsim cadences’ performance for extracting finer information from AGN light curves: time-lags, periodicities and structure-function.

Code Repo: https://github.com/LSST-sersag/agn_cadences, https://github.com/LSST-sersag/maf_metrics Kovačević, Ilić et al 2021, MNRAS, 505, 5012

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Metrics:

• A unified metric related to time-lag and periodicity: ties relative formal error of measured time scale (τ,P) to the characteristics of AGN light curve and OpSim cadence
• Metric related to Structure function: estimate deviations of SFs based on OpSim cadences (termed ”gappy” light curve, SFgappy) from ’reference’ SF obtained from 1-day sampled light curve (SFconti)

Challenges:

• How to unify metrics based on time-lag and periodicity
• To create from scratch OpSim sample of AGNs
• sparser bands such as u-band

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Andjelka Kovačević, Dragana Ilić, Isidora Jankov, Luka Popović, Ilsang Yoon, Viktor Radović, Neven Caplar, Iva Čvorović Hajdinjak , Saša Simić on behalf of AGN SC - all are welcome to join

Blazar Variability

Contributors: Claudia M. Raiteri, Maria Isabel Carnerero,

B. Balmaverde, F. D’Ammando, M. Paolillo, I. Yoon, E. Bellm, W. Clarkson.

We need well-sampled light curves to follow also the short-term variability ➡ combine data in different bands, but problems due to spectral variability

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We need to follow the behaviour of colour indices, built with data in the 2 bands acquired close in time

Light curve sampling test ➡

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Grey=Whole Earth Blazar Telescope published data on 3C 454.3 (WEBT; https://www.oato.inaf.it/blazars/webt/ ).

Blue=LSST-WFD, Green=LSST-DDF , points obtained with TransitAsciiMetric.ipynb and baseline_nexp2_v1.7_10yrs.db.

WEBT Johnson-Cousins B,V,R,I bands are associated to LSST r, i, z,y bands.

Maximize volume and uniformity coverage of Star Forming Regions in the Galactic Plane with Rubin LSST

Contributors: Loredana Prisinzano & Sara Bonito et al.

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Rubin LSST Static photometry as unique opportunity to study large-scale young structures and low-mass populations in the thin disk Galactic Plane, where star formation mainly occurs.

Goal: uniformity WDF footprint including the Galactic Plane (|b|<5 deg) with at least the gri filters

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Metric: number of stars with age <10 Myr and down to 0.3 M⊙, weighted on the maximum distance reachable only with Rubin LSST data

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Result: a gain of 79% is found adopting the gp_smooth simulation rather than the baseline

Supernova Cadence Note

A qualitative assessment of the seven questions from the perspective of supernova science.

Not considered: indirect benefits to SN science (e.g., photo-z estimates improved by additional DDF observations).

Q1 WFD Footprint: Expanding sky area only directly helps SN science if there is little to no loss to cadence or filter coverage.

Q2 DDF / Mini-Surveys: The high cadence (and depth) of DDFs make them especially good for a variety of SN science.

Q3 u-band Exposures: Deeper u-band images would be beneficial if the u-band cadence does not decrease.

Q4 Time Allocation per Band: more time spent in bluer filters could improve low-z SN science.

Q5 Same-Night Pairs/Triplets: with certain filter combinations, triplets can be very beneficial to SN science (Bianco et al. 2018).

Q6 Rolling Cadence: higher-cadence observations have strong benefits for SN photometric classification.

Q7 Dither Patterns: tiling patterns that overlap can boost lightcurve sampling in ~16% of the sky area.

Contributors: Melissa L Graham (U. of Washington), Tyler A Pritchard (NYU), Maria Teresa Botticella (INAF Italy), Federica Bianco (U. of Delaware), Saurabh Jha (Rutgers)

Co-signers: Ashley J Ruiter (UNSW Canberra), Virginia Trimble (UC Irvine), Ragnhild Lunnan (Stockholm University)

Available at: https://www.lsst.org/content/survey-cadence-notes-2021

Optimizing Cadences with Realistic Light Curve Filtering for Serendipitous Kilonova Discovery with Rubin (1/2)

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Contributors: Igor Andreoni, Michael Coughlin, Mouza Almualla, Eric Bellm, Federica Bianco, Mattia Bulla, Antonino Cucchiara, Tim Dietrich, Ariel Goobar, Erik Kool, Xiaolong Li, Fabio Ragosta, Ana Sagues-Carracedo, Leo Singer

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Kilonovae are faint and rapidly evolving extragalactic transients generated by binary neutron star and neutron star--black hole mergers. As such, they are counterparts to gravitational-wave detections and could be the primary sites of heavy element nucleosynthesis in the Universe.

Goal: Compare OpSim to find which cadences and metrics are more suitable to find kilonovae in the Rubin WFD survey, independently of GW or GRB triggers

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Metric: KNePopMetric: recovery of synthetic kilonova light curves by:

• using basic multi-detection criteria
• identifying rapid fading sources with a simplified version of the ZTFReST algorithm (Andreoni & Coughlin et al., ApJ, 2021, in press)

Optimizing Cadences with Realistic Light Curve Filtering for Serendipitous Kilonova Discovery with Rubin (2/2)

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References: Accepted for publication in ApJ Supplement

ArXiv: 2106.06820

Result 1: Kilonova detection efficiencies increase by >20% if 30s exposures are employed instead of 2x15s exposures

(see Fig. 1)

Result 2: New rolling cadences can enable the identification of more kilonovae as rapidly fading transients; further improvement of rolling cadences could lead to the unveiling of an even larger population (Fig. 1)

Result 3: Adding more exposures in i-z-y filters (as opposed to u-g-r filters) can enable the identification of significantly more kilonovae at low redshift, which is better for multi-wavelength follow-up (Fig. 2)

Figure 1

Figure 2

Cadence impacts on reliable classification of standard-candle variable stars, including detection of amplitude period, phase modulation effects (Blazhko effect)

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Contributors: Nina Hernitschek, Keivan Stassun

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We have developed a metric PeriodicStarModulationMetric to evaluate the feasibility of recovering light-curve modulation in RR Lyrae stars, such as caused by the Blazhko effect.

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Evaluating FoM:

area for which a given fraction of RRab stars at a given DM can be correctly detected, i.e. the light curve parameters retrieved within allowed tolerances, from observations within 20 - 50 days.

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example: rolling cadence, DM=19, 20 day light curve

Classical variable stars in different Galactic environments: pulsation behaviour recovery

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Goal: Analyze the performance of different LSST OpSim strategies to recover accurate periods, mean magnitudes and amplitudes for different types of pulsating stars characterized by different light curve shapes and ranges of period, absolute mean magnitude and amplitude (Type ab and c RR Lyrae, Cepheids, Long Period Variables, δ Scuti).

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FoM: Errors on the recovered period, mean magnitude and amplitude as function of the number of years of observations

Open issues: Period alias problem with all the tested OpSim

Metrics:

For the Cadence Note, we have constructed a notebook including some new metrics that we are updating and upgrading (also to make them user-friendly and publish on github).

These are based on a theoretical model or an empirical template for a variable star.

Lccontructor.py: generates the simulated multiband light curves adopting a particular OpSim and set the environment (distance, reddening) in which we are interested to observe/analyse variables

SaturationStacker.py: is used to remove the saturated points for the selected OpSim (This has to be further modified to include crowding contribution)

Multifilter GATSPY package to recover period is applied (when needed)

Lcfitting.py: performs the fit of the phased light curve (a fixed number of harmonics are allowed so far - This has to be updated).

Contributors: I. Musella, M. Di Criscienzo, V. Braga, S. Leccia, M. Dall’Ora, G. Fiorentino, M. Marconi, R. Molinaro, V. Ripepi, G. Bono, M. Trabucchi, L. Girardi, G. De Somma, TVS & SMWLV SCs

Classical variable stars in different Galactic environments: pulsation behaviour recovery

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Theoretical Light curve/template for classical pulsating variable (RRab, RRc, Cepheids, LPV, delta Scuti)

LCconstructor: Simulated light curves with Rubin-LSST sampling after 2 yrs (left) and 10 yrs (right)

LCfitting: Fitting of simulated light curves after 2 yrs (left) and 10 yrs (right)

NOTEBOOK

FoM

ugrizY Delta mean magnitudes obtained for the RRab versus the OpSim index after 2 (left panel), 6 (middle panel) and 10 (right panel) years of survey.

Adopted OpSim

Analogous FoMs for Period and Amplitude

AGN Photometric Redshifts

Assef, Temple, Richards, Yu & Bauer on behalf of the AGN SC

Aim: General considerations of survey strategy on AGN photo-z quality

• Accurate colors
• Deep u-band to target IGM absorption/Lyman break at z≳1.7
• Long inter-band cadences affect quality due to variability

Results

• Prefer deeper stacked u-band depths
• No OpSim was critically detrimental for colors and u-band depth
• Avoid baseline_samefilt as it results in systematically longer inter-band cadences for all contiguous filters

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Quasar Number Counts

Assef, Temple, Richards, Yu & Bauer on behalf of the AGN SC

Aim

• Estimate expected number of quasars to be detected in WFD for every strategy.
• Update estimates on Science Book
• Based on 10yr stacked i-band

Results

• WFD: ~11M, ranges from 6M to 14M
• ~15 million in WFD+mini-surveys
• Differences due to area not depth, number density remarkably consistent
• Prefer wider footprint strategies

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Microlensing towards the Magellanic Clouds:

searching for long events

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Contributors: Tristan Blaineau, Marc Moniez et al.

Aim: for a cost of less than 40 hours, 4 × 1000 images (all filters) towards 4 LMC fields, reasonably spread over the 10 years of the survey, will provide decisive constraints on the intermediate mass black holes contribution to the Galactic halo.

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Take home message: Microlensing detection due to massive lenses will suffer greatly from sampling that would not return for more than a year on the monitored field.

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Missing 1 to 8 consecutive seasons: impact on the detection efficiency of long time-scale microlensing events

Detection of interstellar scintillation by high frequency imaging of the LMC or SMC Contributors: Marc Moniez, Reza Ansari, et al

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What? Stars twinkle when their light propagates through turbulent interstellar H₂ gas

How? ~1% of modulation expected at a few minute scale for small size stars (V > 20)

-> High cadence with big telescope needed = LSST

Cost? 2 movies of a few hours in G toward one LMC/SMC field

-> sufficient to establish constraints on H₂ within the Galactic Halo

The Vera Rubin Observatory Cadence Note

Milky Way Globular Clusters

Review and update physical properties

of Galactic globular clusters.

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Digging deeper intro the core of Galactic globular clusters through multicolor and time-series photometry to review and corroborate known variables, but also to discover and characterize new variable sources from millisecond pulsars to long-period variables.

R. Figuera Jaimes, Rosanne Di Stefano, Rachel Street, Yiannis Tsapras, Markus Hundertmark, and Etienne Bachelet

Plot in Galactic coordinates showing the 157 globular clusters so far known in our Galaxy. The clusters in blue correspond to those with latitudes between +15 to -15 (red lines). Clusters in red correspond to those with the highest central luminosity density.

https://rojofija.com

Microlensing Discovery and Characterization Efficiency at Different Timescales in the Vera C. Rubin Legacy Survey of Space and Time

Contributors: Natasha S. Abrams, Somayeh Khakpash, Rachel Street, Etienne Bachelet, Yiannis Tsapras, Markus Hundertmark, Marc Moniez, Tristan Blaineau, and Rosanne Di Stefano

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Aims:

• Analyze the effect of LSST cadence on relative discovery rate of microlensing events
• 4 event timescales: 0 - 10, 10 -30, 30 -100, and 100 - 300 days
• Using N^2 and Besancon galactic models

Results:

• Generally higher percentage of Galactic Plane Covered → Higher Discovery Rate
• Generally longer duration events → Higher Discovery Rate (depending on event distribution)

Follow-Up Work:

• Using Fisher Matrix to measure characterization rate

Tidal disruption events:

Blue coverage will be key for photometric classification

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Contributors: Sjoert van Velzen, Katja Bricman, Matt Nicholl

Signed: Katie Auchettl, Suvi Gezari, Andreja Gomboc, Ilya Mandel, Anil Seth

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Enhancing LSST Science with Euclid synergy in the DDP context

J.-C. Cuillandre, on behalf of the Tri-Agency Survey Coordination Task Force and the Derived Data Products Working Group

To maximize science, the Rubin-Euclid synergy cadence note

• Endorses the DESC recommendation to expend the WFD extragalactic sky coverage to Dec +12.5,−70 (20,000 deg2 total)
• Supports the coverage of the Euclid Deep Field South as a DDF with extended dithering (23 square degrees)
• Supports northern and southern shallow mini-surveys in g,r,i,z extending to Dec +30,-90 to boost the Rubin science (ToO, etc)
• Underlines the importance of 1) maximizing the overlap between the two surveys to maximize the scientific return of the DDP, and 2) synchronizing observations over two deep fields (CDFS, South)

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DDP overlap of the main respective releases for the baseline WFD:

• 2025 LSST WFD Year 1 = 3000 square degrees over Euclid Year 3 (DR2)
• 2030 LSST WFD Year 5 = 7000 square degrees over Euclid Year 6 (DR3)

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Depths (photo-z metric: field galaxy, 10-sigma)

• Rubin LSST WFD Year 5: u=24.6, g=25.8, r=25.9, i=25.2, z=24.5 [Y1+0.9]
• Euclid Wide Survey: VIS (r+i+z)=25.1,Y=J=H=23.5

The Tri-Agency Survey Coordination Task Force for Rubin+Euclid+Roman echoes in its cadence note the two 2018 LSST white papers that led to the current Rubin synergy with the Euclid Wide & Deep Survey South in the context of the Derived Data Products (DDP) Rubin-Euclid joint effort started in 2020

PART 2

QUESTIONS/OPEN ISSUE/FEEDBACK TO SCOC

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Sara (Rosaria) Bonito - INAF - Observatory of Palermo (Italy)

Young stellar objects and their variability

Open issues: TBD

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Feedback for the SCOC: TBD

Contributors: Sara Bonito & Laura Venuti et al.

Interested to join: TBD

Galactic Plane Footprint and Variability Timescales

Outstanding questions

Insufficient time to cover whole GP region, but highest-priority region centers around the Bulge.

• Add sequence of pointings deliberately spaced along -85 > b > +85deg to sample different galactic lines of sight?

Blazar Variability

Outbursts are the most important phases, to study in a multiwavelength context -> need to mitigate saturation

-> 2x15 sec exposures in a visit preferred

Simulation with blazar_saturation_metric: sky

filled with the 3561 known blazars listed in the BZCAT5 catalogue (https://www.asdc.asi.it/bzcat/). The catalog magnitude of each blazar is taken as its base-level brightness, and all sources flare, with flaring timing (period) and characteristics (outburst amplitude and time spent in outburst) randomly determined.

Results obtained with different OpSim runs: the largest number of detected sources and sources detected in outburst are obtained in the runs alt dust..., alt roll mod2 dust..., footprint big sky dust... and roll mod2 dust... The number of saturated observations goes from ∼ 3% to ∼ 6% and the Opsim runs with single exposures of 30 sec perform worse than runs with double exposures of 15 sec. Intermediate saturation levels are obtained with the short exp...(better 5 times a year than twice) and by the filterdist... cadences.

Maximize volume and uniformity coverage of Star Forming Regions in the Galactic Plane with Rubin LSST

Open issues: young stars can be selected to obtain color-color diagram.

Multi-filter observations with at least 3 bands

are fundamental to exploit Rubin LSST static photometry to

detect very young stars at distances unreachable with other

present and future facilities

Feedback for the SCOC: TBD

Contributors: Loredana Prisinzano & Sara Bonito et al.

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Give Me A Few Hours:

Missing Timescales in Rubin Cadence Simulations

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In current simulations, LSST revisit times are strongly peaked at the 22 minute pair separation. There is effectively no constraint on temporal evolution within the night (< 1% of observations), even in current “triplet” configurations.

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Such a lack of intra-night sensitivity would prevent Rubin from discovering a range of astrophysical phenomena and preclude obtaining timely followup.

Contributors: Eric Bellm, Colin Burke, Michael Coughlin, Igor Andreoni, Claudia Raiteri, Sara Bonito

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A resolved census of dwarf satellites around Local Volume galaxies

Contributors: Jeff Carlin, Knut Olsen, Leo Girardi, Jonathan Hargis & SMWLV Science Collaboration

Goal: maximize discovery of dwarf galaxy satellites of Local Volume (1.3 < D < 6 Mpc; i.e., beyond the Local Group) host galaxies. Complete satellite census around hosts of different masses, environments, and morphologies constrains the nature of dark matter and the physical processes governing the number and properties of galaxies inhabiting dark matter subhalos.

• Expect LSST will discover more than 200 dwarfs

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Requires:

• depth well below the TRGB
• large area (e.g., the LMC’s virial radius would subtend 11.5 deg. at D = 1.5 Mpc, and 4.3 deg. at D = 4 Mpc)
• good image quality to enable star/galaxy separation at the faint end, where unresolved background galaxies far outnumber the stars of interest

Stellar mass of Local Volume galaxies* vs. distance from the Milky Way. Color-coding is the fraction of cadence simulations that reach point-source depths sufficient to discover M_V = -7 dwarf galaxies.

*from Karachentsev+2013 (AJ, 145, 101). Online database: http://www.sao.ru/lv/lvgdb/

A resolved census of dwarf satellites around Local Volume galaxies

Figure of merit (FoM): the number of Local Volume galaxies for which the faintest detectable dwarf satellite galaxy is fainter than M_V = −7.

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Survey properties that maximize science goals:

• increased depth in g-band (especially enabled by 1x30s rather than 2x15s exposures)
• time allocated to WFD
• footprint of WFD survey
• optimized good-seeing cadences

Number of LV galaxies with limiting dwarf galaxy detection fainter than M_V = -7. A total of 139 galaxies at D<6 Mpc were considered.

Outstanding questions/issues not considered:

• We focused on satellites of known host galaxies, but the depth and area of LSST will uncover many isolated (dwarf) galaxies in the Local Volume.
• Discovery of unresolved dwarfs at distances >6 Mpc -- see, e.g., the Galaxies SC’s cadence note.
• Scientific studies of the main bodies of host galaxies will benefit from good seeing and multi-band photometry.

Bulge Stellar Populations with LSST

Goals: trace bulge structure and kinematics; metallicity and age diagnostics sufficient to disentangle bulge formation history; legacy dataset for future studies

General indications:

• deep u-band imaging required; more depth generally better. Prefer 1x50s in u to 2x15s;
• Filter uniformity among grizy generally preferred over strategies with red or blue bias
• Wide-Fast-Deep extension to the plane is generally preferred; uniform plane coverage slightly better than “low-dust” plane coverage;
• Allocating at least 180 exposures to the inner plane is preferred, with some coverage required in years 1 & 10.

Max distance (in pc) with red clump [Fe/H] sensitivity < 0.2 dex

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See the 2021 Cadence note “Bulge Stellar Populations with LSST” for details

Contributors: Will Clarkson, Massimo dall’Ora, Alessandro Mazzi, Leo Girardi, Victor Debattista, Annalisa Calamida, Oscar Gonzalez, R. Michael Rich, Christian I. Johnson, Knut Olsen, G. Bono, G. Fiorentino, Xiaolong Li, R. Szabo

Bulge Stellar Populations with LSST

Goals: trace bulge structure and kinematics; metallicity and age diagnostics sufficient to disentangle bulge formation history; legacy dataset for future studies

Outstanding questions / issues under development:

• jupyter → MAF; translating input into more direct tradeoffs, e.g.:
• What is the minimum coverage (e.g. area towards the bulge) acceptable / desirable for science goals?
• What is the minimum coverage needed for a “good” seeing-limited legacy survey (K. Olsen et al. cadence investigation underway)

Figures of merit implemented to-date:

• Distance at which (u-i)₀ → [Fe/H] uncertainty < 0.2 dex (for Red Clump Giants; Johnson et al. 2020)
• Volume in which RR Lyrae can be measured to <= 0.04 mag in grizy
• Sensitivity to variability (n_exposures x TRILEGAL n_stars (r<22))
• Measuring bulge MSTO populations (Gonzalez et al. 2018 CWP)

Volume with [Fe/H] sensitivity for Red Clump Giants to 0.2 dex or better

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See the 2021 Cadence note “Bulge Stellar Populations with LSST” for details

Contributors: Will Clarkson, Massimo dall’Ora, Alessandro Mazzi, Leo Girardi, Victor Debattista, Annalisa Calamida, Oscar Gonzalez, R. Michael Rich, Christian I. Johnson, Knut Olsen, G. Bono, G. Fiorentino, Xiaolong Li, R. Szabo

Saturation & Bright Objects

Goals: 1. Allow calibration of highly saturated objects in program exposures; 2. improve the tie to external catalogs; 3. cover scientifically interesting targets that saturate at program exposure length.

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For more, see: Gizis et al. (2018 CWP); chapters 10.2 (Trilling & Jones) and 10.3 (Stubbs) in the COSEP.

Object counts observed below a fiducial saturation limit in any of {long, short} exposures.

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For details, see the “Saturation & Bright Objects” cadence note

General indications:

• Recommend multiple short (>= 5 x 2s) exposures in every filter each year
• Some short exposures should be taken outside twilight;
• Sufficient twilight time should be reserved for parallax measurement
• For program observations, 2x15s probably preferred over 1x30s to minimize saturation at program exposure time

Contributors: Will Clarkson, Alessandro Mazzi, Xiaolong Li, Claudia M. Raiteri, Maria Isabel Carnerero Martin, John Gizis, Loredana Prisinzano, Sara Bonito, Massimo dall’Ora, Robert Szabo, Rachel Street

Saturation & Bright Objects

Outstanding questions: �

• Not much simulation coverage in FBS 1.5-1.7.1 (quite reasonably!) What simulations do we need to explore questions like the following?
• What short-exposure strategy is needed to allow flux measurement for very bright objects in the program exposures? (e.g. is 5x2s per year per filter too much? Too little? What is the minimum set?)
• Seeing requirements? e.g. is it better to do short exposures when the seeing is worse?
• Scientific: any advantages to particular filter distribution?
• What are the tradeoffs against other science goals? (e.g. minisurveys? DDFs? Parallax measurement?)�
• Other questions:
• How well can the short:long exposure calibration be handled during commissioning? Scientific reasons for repeat short exposures?

Exposure count at < 20s (in r) in example OpSim with short exposures

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For details, see the “Saturation & Bright Objects” cadence note

Contributors: Will Clarkson, Alessandro Mazzi, Xiaolong Li, Claudia M. Raiteri, Maria Isabel Carnerero Martin, John Gizis, Loredana Prisinzano, Sara Bonito, Massimo dall’Ora, Robert Szabo, Rachel Street

Brown Dwarf Astrometry

Figure of merit (FoM): The relative volume of space in which the distance (parallax) of L4 or L7 dwarfs can be measured to 10% accuracy. (Solar neighborhood is uniformly distributed on the sky for this purpose.)

The baseline results for L7 dwarfs. In the WFD footprint, brown dwarfs can be measured to 45-50 pc.

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John Gizis (U. Delaware)

Outstanding questions/issues not considered:

• Twilight time effects of Satellite Constellations

Key Issues

• Major advance over Gaia for L and T dwarfs.
• Need robust WFD survey. Minimal “Big Sky” survey does poorly
• Need for red filters (z,y)
• Tension with twilight surveys. Parallax needs observations early and late in the night.
• Prefer wide area (WFD, mini-surveys) over pencil beams (DDF)
• No preference on Rolling Cadence, Dithering Strategy
• Favor single snaps.
• Importance of astrometric noise floor, can be calibrated via Gaia.

Classical variable stars in different Galactic environments: pulsation behaviour recovery

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Open issues: Period alias problem with all the tested OpSim

Theoretical Light curve/template for classical pulsating variable (RRab, RRc, Cepheids, LPV, delta Scuti)

LCconstructor: Simulated light curves with Rubin-LSST sampling after 2 yrs (left) and 10 yrs (right)

LCfitting: Fitting of simulated light curves after 2 yrs (left) and 10 yrs (right)

NOTEBOOK

FoM

ugrizY Delta mean magnitudes obtained for the RRab versus the OpSim index after 2 (left panel), 6 (middle panel) and 10 (right panel) years of survey.

Adopted OpSim

Analogous FoMs for Period and Amplitude

DESC R&D after Cadence Notes Call

Further R&D

• Decoupling extragalactic and Galactic survey strategies to optimize both.
• Rolling cadence is a promising solution to address the trade-off between area and depth
• Need R&D to getting rolling to work for both transient science (sensitive to cadence) and static science (sensitive to uniformity at specified intervals) - balance might be achieved by “pausing” the rolling near certain data release times.
• True alt-sched like scheduling of observations

(alt-sched: deterministic scheduler; leads to observations as close to the meridian as possible, while alternating between sky regions North and South of the observatory latitude on alternate nights; cycles through the filter set and changing filters after observing blocks.)

• Important to have nearly uniform data releases at certain times e.g., Year 1, 2, 4, 7, 10 to enable a series of cosmology analyses. Near-uniformity can result from a combination of survey strategy and creating a nearly-uniform release by “postponing” the latest data in unusually deep regions of sky until the subsequent release.
• Need R&D to develop a metric that assesses whether a sufficiently uniform data release is available at Years 1, 2, 3-5, 6-8, 9-10.
• DDFs: cadence (rolling) optimization + more time allocation

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Survey Strategy III (Thurs 10:30)

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We need to strategize on how to incorporate all the metrics that the community has created from all the Science Collaborations in the SCOC decision framework.

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• Notes: https://docs.google.com/document/d/1ybOVJ6oWEkgng7cn0XtRGK1dGWohdYjR1xWdkpqaoqU/edit?usp=sharing&urp=gmail_link
• Slides (anyone can continue contributing feedback for the SCOC meeting in Nov. 2021): https://docs.google.com/presentation/d/1kVSdClzcM1EJ3zWhSg6Aza-1Nf_AdjPwme5HaL-RDR8/edit#slide=id.ge6d80895ae_3_235
• Talks:
• SC submissions, an overview (Federica Bianco)
• Time domain science in the Galactic Plane and Magellanic Clouds (Rachel Street)
• AGN & Blazars (Andjelka Kovacevic)
• Supernovae, Kilonovae & TDE (Igor Andreoni)
• Stars, Milky Way and Local Volume (Jeff Carlin)
• Data Analysis (Weixiang Yu)
• Anomalies and True Novelties (Xiaolong Li)

Future: Continue work done by SCs Task Force, e.g. Transients & Variable Stars (TVS) & Stars, Milky Way, and Local Volume (SMWLV) Task Forces (2020 - 2021): SMWLV: W. Clarkson, S. Bonito, A. Calamida, J. Gizis, D. Monet, K. Olsen, M. Rich, J. Strader, N. Walton; TVS: R. Street, R. DiStefano, F. Bianco, C. Raiteri, I. Andreoni, A. Kovacevic, M.W. Coughlin, R. Szabo, I. Mandel, I. Musella, S. Bonito, S. Leccia, D. Ilic, G. De Somma, M. Marconi, M. Carnerero

• Strong Lensing (Timo Anguita)
• Galaxies (Benne Holwerda)
• TiDES Extragalactic Survey (Jon Carrick)
• Dark Energy (Humna Awan)
• Solar System (Laura Inno)

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Thank you!

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88

Speaker: S. Bonito

Session Organizers: Sara (Rosaria) Bonito (Chair); Rachel Street, Will Clarkson, Federica Bianco, Andjelka Kovacevic, Dragana Ilic, Maribel Carnerero, Ilaria Musella; SCOC and OpSims experts: Peter Yoachim, Knut Olsen, Jay Strader

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Vera C. Rubin Observatory | Project & Community Workshop | 9-13 August 2021

Acronyms & Glossary