2019 SB Gaia Sprint

pitch slides

KITP — 2019 March 25

Adrian Price-Whelan (Princeton)

plan to do:

  • Infer true spatial (on sky) density structure of GD-1
  • Improve phase-space models of known stellar streams (e.g., GD-1, Pal 5)
  • Confirm / re-discover some other “known” streams

want to learn:

How to construct a very specific selection function in the GD-1 footprint

will bring:

Expertise in Python/Astropy; Gaia data access and use; galactic dynamics and practical tools; stellar streams; Bayesian inference

want to discuss:

Stellar populations of globular clusters vs. ultra-faint dwarf galaxies; dynamical inference / dark matter; star / globular clusters

Eugene Vasiliev (Institute of Astronomy, Cambridge)

Want to do:

  • use mixture models in parallax+PM+colour space for membership selection
  • search for extended structures around star clusters
  • build dynamical models of star clusters using Gaia+other data(?)

Want to learn:

  • how to find and access other sources of astronomical data besides Gaia

Can share:

  • how to cope with systematics in Gaia astrometry
  • galaxy modelling framework Agama: potentials, actions, dynamical models...

Alice Quillen University of Rochester, Rochester NY

What I want to do:

    • Look for kinematic patterns associated with recent star formation.
    • Improve models for the stellar phase space distribution function that are sensitive to relaxation and resonance

What I want to learn:

    • How to create and work with nice databases of stars

What I bring:

    • Multidisciplinary approach to dynamics modeling, dynamics theory and particle based numerical simulation. Javascript, python, rebound

What I want to discuss:

    • How to create a better 3D and time dependent model Milky Way
    • Classification projects for future large data sets

Lorenzo Rimoldini (University of Geneva, CH)

What I want to do:
1. Classify variable objects without time series: how far can we go?
2. Any
δ Scuti or SX Phoenicis fans to validate the Gaia DR2 candidates?
3. How to best exploit the public time series of
unpublished variability classes?

What I want to learn: complementary data sets; streams; local dark matter density

What I bring:
1. Gaia DR2 variable stars + Classification of high-amplitude pulsators
How to access, crossmatch, and get started with the Gaia DR2 data
3. (Semi-)supervised classification and all what is needed to make it work

What I would like to discuss: variability phenomena; unsupervised classification; quasars; gravity

Zhen Yuan (Shanghai Astronomical Observatory)

plan to do:

  • Finding tails of existing GCs
  • Dynamical Evolution of GCs in the MW

What I bring::

A new clustering method StarGO based on self-organizing-map (unsupervised neural network learning)

Applications: Substructures, Star Clusters, Any Clustering Projects


Member Identification

For NGC 5824

want to learn:

  • Statistical tools (e.g. non-parametric way to decompose multiple Gaussians)
  • A variety of ways to download Gaia data
  • Mock MW from Latte Simulations

want to discuss:

  • Archeological Fossils: Dwarfs & GCs
  • What can we learn from abundances?

Giuliano Iorio

  • Look for halo structures in phase-space using RRLs
  • RRLs around GCs, RRLs in known streams

RRLs in Pal-5 stream

(Institute of Astronomy, Cambridge)

RRLs around M5

4 Rt

Want to do:

Want to learn:

Ask me about / What I bring:

Want to discuss:

  • Methods to estimate the phase-space density
  • Clustering methods / Associate stars to known GC/Sats/streams

  • MW stellar halo
  • RRLs in Gaia

(I bring catalogs of all RRLs classified in Gaia DR2 with additional information)

  • (non cosmological) N-body simulations

(I bring catalogs of an LMC-like destroyed in the MW, credit D. Erkal)

  • Gaia selection function / completeness
  • How to find shells in the MW halo
  • Can we improve distance estimate for RRLs?

Timothy Brandt

  • Want to do: calibrate uncertainties for the medium/faint end of Gaia astrometry: Tycho, WFPC2? ACS?
  • Want to learn: how else can we understand Gaia uncertainties and systematics?
  • What I bring: Cross-calibration of Gaia DR2 to Hipparcos (HGCA), fitting orbits with the HGCA, RV, imaging
  • Want to discuss: how can we get the best handle on spatially correlated systematics, external uncertainties?

P~100-400 years

Paolo Tanga - Observatoire de la Côte d’Azur

What I want to do:

    • Exploit ~200 million asteroid positions reduced with pre-Gaia catalogs
    • Optimize my brand new approach to correct zonal errors for those catalogs
    • Study the results and start writing an article!

What I want to learn: write better ADQL queries, launch python parallel threads, and all that you can share about systematics in ancient catalogs.

What I bring: Solar System data expertise. Zonal error corrections for ~3000 asteroids, ~20 catalogues. Independent cross-match approach.

What I would like to discuss: Spatially correlated errors. Clustering algorithms for multi-dimensional data. Good beers.

Larry Widrow Queen’s University

Want to do: Apply methods such as Gaussian process regression to Gaia data to build models for the phase space DF.

Want to learn: Better methods for GPR including application of sparse GP to problems in 3-6 dimensions and with observational errors.

What I bring: Preliminary success modelling 3D velocity field via GPR. Familiarity with GPy. Have also worked on building equilibrium disk models and embedding them in cosmological halos.

What I want to discuss: Theoretical underpinning of phase space structure in stellar DF and other methods to analyse both data and simulations.

Alexa Villaume (University of California Santa Cruz)

What I want to do:

What I want to learn:


What you can ask me about:

SQL databases

Stellar population

synthesis models

  • Cross-match E-IRTF library with Gaia
  • Normalize spectra to Gaia photometry
  • Infer luminosity for each E-IRTF star in manner similar to Hawkins et al. 2017

How to choose informative priors when using the parallax measurements

Use Gaia to turn the E-IRTF stellar spectra library into new SPS models

Kathryn V Johnston (Columbia University/CCA)

dynamics-driven data analysis of PS-spiral

prior work and best data for this
python tips and toolkits

direct experience in prehistoric times

anything and everything

Images from Aaron Tran (Columbia)

Andy Casey (Monash)

What I want to do >> use eclipsing binaries to translate excess astrometric noise to tangential motion, and estimate inclination angles for non-eclipsing binaries

What I want to learn >> is the distribution of inclination angles isotropic?

What I bring >> Zen. My time (for your Sprint problems). Experience in data analysis, some knowledge about stars

What I’d like to discuss >> astrometry >> (other things….) >> thoughts about next Gaia data release

Lauren Anderson (Flatiron Institute)

What I want to do: apply our method for modeling a 3D dust map to real data, profile the python code to minimize compute time, sprint with Juna

What I want to learn: data viz with yt (3d rendering and sim reconstruction), limits of GP method with real data, more intuition for how approximate GP methods work

What I’d like to chat about: interpreting structures in a 3D dust map, including velocity in the dust map, non-parametric representations of galactic potentials, inference of the MW halo shape/accretion history from stellar streams, structures in the CMD, modeling and interpreting the phase space distribution function of stars

What I bring: GP 101 description, data-driven models, curiosity and optimism

Sarah Pearson

Credit: Eilers & Hogg


v_r vs v_phi correlation

What I want to do:

Re-compute Eilers’ plot for galactic bars formed through two different scenarios:

  • In-situ (E. D’Onghia’s simulations)
  • Sagittarius impact (C. Laporte simulations)

What I hope to learn:

How long is the Milky Way’s Galactic bar?

How did it form? (optimistic question)

Which orbits support the bar? (using APOGEE/Gaia 6D info)

What can we learn about the bar from APOGEE metallicities?

You can ask me about:

- Galactic dynamics/the Galactic bar

- Orbit integration

- Using Price-Whelan’s Gala package

I’d like to chat about:

- APOGEE selection function

- The Galactic bar in general

Flatiron Institute,

Center for Computational Astrophysics

Luis Quiroga-Nuñez (Leiden Observatory/JIVE)

  • Cross-matches at different λ
  • Variability for evolved stars.
  • Galactic structures
    characterization (arms & bar)

  • Radio astrometry at 1μas
  • Experience generating
    simulated astrometric data.
  • Radio data that complements Gaia results in the GP
  • How variability can be obtained from Gaia ?
  • How extinction maps are used
    over Gaia data?
  • Generate MLE to test the Gaia

  • Members of stellar association
  • Synergies between astro-
    metric campaigns at different λ
  • Stellar population across the GP
  • Future missions in IR?...plausible?

What I want to do

What I want to learn

What I bring

What I like to discuss

Jason Hunt (Dunlap Institute - Toronto)

What I want to do: Explore the non-axisymmetric & disequilibria structure in the Gaia data

What I want to learn: How to differentiate between signatures of bars/spirals/external perturbers

What I bring: Dynamical Galaxy modelling methods / knowledge; N-body, Test particle, Action-Angle (and models themselves), with various bars+spirals

What I’d like to discuss: Reconciling long/short bar evidence, I don’t mind who’s right, I’d just like to know!

Andrew Wetzel (UC Davis)

to do

  • understand origin (and lack thereof!) of alpha/Fe bimodality in Latte simulations, connection with stellar kinematics (and ages), test this formation scenario with Gaia++
  • convince you to use our (really Robyn’s) Ananake synthetic Gaia DR2 catalogs from our Latte simulations

to learn

  • how better to compare kinematics, abundances, and ages from Gaia + APOGEE + ??? against simulations


  • Ananake synthetic Gaia DR2 catalogs and full snapshots of Latte simulations (i.e. I am happy to point you in Robyn’s direction)
  • sarcasm

to discuss

  • joint analysis of abundances + kinematics + ages


  • Galactic/DM dynamics
  • Secular evolution/kinetic theory
  • Impact of LSS on galaxies

Would like to learn more about

  • GAIA’s constrain on DHs
  • Who wins, when, where in driving galaxies’ fate?

What I bring

  • Understanding(?) of LSS + secular. dynamics

Do discuss

  • What can be done with GAIA streams/ridges?

Happy to work with anybody interested...

What I want to do

  • Modify kinetic theory for streams
  • Map ridges in Gaia coordinates
  • Convince people quasi-linear theory rocks

Patrick LaChance

What I want to do:

  • Disentangle the qualities of the kinematic background in the solar neighborhood from the nearby clusters

What I bring:

  • I bring a clustering algorithm (SNN) that can group stars together based on a variety of attributes (position, velocity, chemistry, etc.) that was developed in our group.
  • I bring some data structures and analysis experience from my CS background.

What I want to learn:

  • I want to learn about the kinematic features of our solar neighborhood, and spiral galaxies in general.
  • I would like to learn the ages and metallicities of the clusters in the solar neighborhood to differentiate them from the background

University of Wisconsin-Madison;

4th year undergraduate student working with Elena D’Onghia

Alexandra Borukhovetskaya University of Wisconsin - Madison

undergraduate student working with Elena D’Onghia

What I want to do:

I am interested in understanding the Arcturus moving group - its members and origin. I am hoping to be able to rebuild the group so that I may argue for either in situ or extragalactic formation.

What I want to learn:

Ages and metallicities of known Arcturus members as well as other clustering techniques.

What I bring:

Clustering algorithm (SNN) developed in our group, previously used for kinematic and chemical clustering for globular clusters and now modified for clustering in Gaia data - proper motion, ra, dec, and parallaxes.

Elena D’Onghia (University of Wisconsin-Madison/Flatiron Institute)

I will work on understanding the formation of moving Pleaides, Coma Berenice (with Patrick LaChance) and on Arcturus moving group (with Alexandra Borukhovetskaya)

I want to learn about ages and metallicities of moving groups and the open clusters

I bring dynamical models with N-body simulations and experience on galactic dynamics

Juna Kollmeier (Carnegie Observatories)

What I want to do: I would like to produce useful “Gaia Gold Catalogs” for quasars, single stars and white dwarfs. Or something cooler with Anderson. Maybe some BHBs?

What I want to learn: The pitfalls of producing such catalogs; particularly how to best cut the Gaia data

What I bring: broad interests and expertise

What I want to discuss: I will want to discuss anything

Hamish Silverwood

ICC, University of Barcelona


-Gaussian Process Regression on binned velocity and tracer density data →

-Apply to Jeans Equations to derive force maps and/or disequilibria maps (Δ-Jeans method from Sprint 2018), working with Lauren Anderson & Larry Widrow.


Anything GP related. Selection functions.


Broad Dark Matter knowledge (indirect, direct detection etc). Expertise in Jeans Modelling. Oscar - brute force tool for binning Gaia data incorporating full uncertainties.


Dark matter. GPs. Future measurements of stellar accelerations with high precision spectrographs & nano-arcsecond astrometry (1812.07581).




Harshil Kamdar


Plan to do: can angles between very wide co-moving pairs in data (>2 pc) tell us about whether stars are born together?

Want to learn about: hierarchical star formation.

Can help with: the lifecycle of star clusters born in the disk, clustering algorithms.

Would like to discuss: the ISM! And what we can learn about clustered star formation from Gaia.

A simulation of all stars born in star clusters in the Milky Way disk in the last 5 Gyr that includes a realistic potential (bar + spiral + GMCs) and a subgrid model for cluster birth and evolution

Cecilia Mateu (UdelaR, Uruguay)

What I bring:

  • RR Lyrae stuff + Gaia RR Lyrae completeness maps, PyMGC3, Galstreams library - compilation of MW stream footprints

What I want to do:

  • Calibrate MG for RR Lyrae stars as a function of period-shift (location on Period-Amplitude diagram)

OoII RRLs are brighter than OoI:


= 10% in


What I want to learn:

  • Statistical tools to deal with error systematics & correlations

What I want to discuss:

  • New analytical models for the disc’s density profile to replace double exp+flare+warp

Anthony Brown (Leiden Observatory)

What I want to do

  • Build a “Gaia for beginners” catalogue, intended for use in, e.g., astronomy education (thanks Juna for suggesting this!)
  • Gaia DR2 sub-sample cleaned from the nasty bits, documentation, warnings on limitations

What I want to learn

  • Can the “phase spiral” really be explained as due to moving groups (arXiv:1903.08325)?

What I bring

  • Gaia expertise: all aspects of the data, quality filtering, archive access, ...

What I want to discuss

  • Your thoughts on future Gaia data releases
  • How to preserve sufficient likelihood information in long term Gaia archive
  • Gaia selection function: your inputs on a good proposal to fund this effort
  • Uncertainties/systematics: how will these affect cross-calibration of other/future surveys against Gaia?

Christina Eilers (Max Planck Institute for Astronomy)

you can ask me about: distances to APOGEE red giant stars, Gaussian processes, the Milky Way’s circular velocity.

sprint idea: find, map & model non-axisymmetric features of the Milky Way.

I hope to learn about: Galactic bar, spiral arms, how to install galpy & calculate actions.

Hans-Walter Rix Max Planck Institute for Astronomy, Heidelberg

you should ask me about: SDSS-V
the perfect spectroscopic match to Gaia...

seeking collaboration on Gaia (DR2) as a time-domain survey: DR2 provides rms variations in flux, astrometric wobble, and vlos

(non-)variable WD candidates/contaminants

rms fractional flux variation in G

and their light-centroid wobble

Kohei Hattori (University of Michigan)

to do

  • Identify chemo-dynamical substructure in the stellar halo using clustering algorithms
  • Estimate the shape of dark matter halo using hyper-velocity stars
  • Use orbits of runaway stars to identify their natal star clusters

to learn

  • Clustering algorithms
  • Density distribution of young stars (<10Myr) in simulations.
  • Chemistry/age of known young massive clusters (e.g., Westerlund 1).
  • Basics on photometric metallicity

  • Why sometimes, two mathematically equivalent ADQL queries take very different times.
    • (E.g., “Select ra from AAA where (ra < 10)” and “Select ra from AAA where (ra - 0.5 < 9.5)”)
    • Any tips for reducing the ADQL query times.
  • Does anyone use astroquery? Is there any ways to run ADQL queries other than Gaia archive?

to bring

  • Knowledge on hyper-velocity stars / runaway stars
  • Practical use of AGAMA code

to discuss

  • Gaia Sausage / Disc substructure (e.g., Hercules stream)
  • Any bold ideas using Gaia data

Siddharth Mishra-Sharma (NYU)

What I want to do:

  • Understand collective effect of Galactic dark matter substructure on stellar velocity/acceleration fields (dynamical + lensing-induced)
  • Look for this pattern in Gaia DR2

What I want to learn:

  • Working with Gaia data!
  • Estimators and techniques to look for structure in 3D vector fields, accounting for uncertainties (e.g., extensions of 2-point correlations)

What I bring:

  • Background in astrophysical signatures + particle physics properties of dark matter
  • Experience in writing fast Python code

What I’d like to discuss:

  • Particle physics implications of DM substructure (population) measurements

Substructure lens-induced...

… velocity field

… acceleration field

Jackie Faherty, American Museum of Natural History

Do: Figure out what the end of the main sequence in Gaia looks like and find new objects (young especially!)

Learn: About hypervelocity stars in vtan space

Bring: The end of the main sequence and science visualization

Discuss: Visualizing our data!

Sihao Cheng Johns Hopkins University

What I want to do >> white dwarf H-R diagram

  • Explain the Q branch
  • WD-WD merger rate

What I want to learn >>

optimal quality cuts; selection function; dust within 250 pc

What I bring >>

  • white dwarf knowledge:

cooling, merger, spectra, ...

  • experience in DR2 light-curves (effect of extended sources)
  • scanning directions of Gaia

What I’d like to discuss >>

  • Gaia selection function
  • Gaia-Panstarrs cross-matching
  • bifurcation of Sagittarius Stream
  • spiral arms in stellar mass / gas


May Gade Pedersen (KU Leuven, Belgium)

Plan to do:

  • Determine luminosities of pulsating stars
  • Search for stellar clusters w. EMSTOs and fit isochrone clouds

Want to learn

  • Application of Gaia astrometry and photometry to stellar clusters
  • Cluster membership verification

Ask me about

  • Asteroseismology/seismic modelling of pulsating (massive) stars
  • Internal mixing and impact on stellar evolution and surface abundances


Victoria Antoci

Isochrone Cloud

Heidi Newberg (Rensselaer Polytechnic Institute)

plan to do:

Explore the shell structure in Virgo and related halo substructure

want to learn:

Is the shell structure in Virgo the same as the

Gaia-Enceladus/Gaia-sausage merger and how old is

that structure?


Expertise in structure of the Milky Way halo and disk.

want to discuss:

How do we fit N-body simulations to Milky Way shell


David W. Hogg
(NYU) (MPIA) (Flatiron)

What I want to do >> Map non-axisymmetries in the disk with red-giant stars.
>> Dynamically model the GD-1 spur.

What I want to learn >> How to classify stellar variables using Gaia noise information.

What I bring >> Expertise in computational data analysis, linear algebra, Bayesian inference, model building, MCMC. >> Knowledge about SDSS, BOSS, APOGEE, HARPS, Kepler, and Gaia.

What I’d like to discuss >> Hierarchical models. >> The Gaia likelihood function.
>> Mapping the dark matter. >> Chemodynamics. >> Binary stars.

Jason Sanders

(Institute of Astronomy, Cambridge)

What I want to do - 3d bulge (chemo-) dynamics with Gaia RVS M giants. Photometric metallicities → distances.

What I want to learn - kinematic differences between metal-rich & metal-poor populations across bulge.

What I bring - knowledge on ages/distances from Gaia+spectro, action-angles, streams, bar/bulge.

What I want to discuss - 3d extinction mapping, photometric metallicity/ages, RVS selection fn, bar’s impact on SN kinematics.

Li et al. 2016


WISE colour

Borja Anguiano - University of Virginia

What I want to do: Characterize the kinematic signature of the Galactic stellar warp using APOGEE and Gaia data-sets.

What I want to learn: I noticed that recent works are pointing out new ways of using Gaia flags. I would be interested to have a discussion with Gaia experts about it.

What I bring: Knowledge and experience working with APOGEE, GALAH and RAVE data, this can be useful for this meeting.

What I want to discuss: Stellar multiplicity using different RV visits in RAVE.

Sukanya Chakrabarti (RIT)

Plan to do:

  • How do MW satellites affect the gas & stellar disk ? Including new satellites discovered by Gaia


  • SPH & test particle

simulations, galactic dynamics, variable stars

Want to discuss: happy to discuss anything!

Levine, Blitz & Heiles 06

Chakrabarti & Blitz 09

Josh Simon (Carnegie Observatories)

What I want to do: Photometrically select metal-poor stars by combining broadband colors from Gaia and other all-sky surveys

What I want to learn about: Efficiently cross-matching large catalogs, spectroscopic surveys covering bright (V<14) stars

What I bring: Knowledge of dwarf galaxies and stellar streams (in Gaia and elsewhere). Beginner’s ability to model orbits with galpy.

Other things I want to talk about and/or work on: Dwarf galaxies, stellar streams

1962 version:

Wallerstein (1962)

2019 version?

Ellianna Schwab Abrahams (UC Berkeley, CTDI)

Plan To:

  • Search for anomalous RV measurements using ensemble learning
  • Predict RV measurements for stars without measurements
  • Also very interested in the DR2 Time-Series Catalog and variable star classification

Hope to Learn:
Systematics in the Gaia RV Catalog Edge detection and clustering methods

Bringing/Ask me About:
ADQL Queries Database Crossmatching Representation ML Time Series Featurization

Want to Discuss:
Gaia in the time domain, in DR2 and future DRs Detecting variability using static data

Morgan Fouesneau

What I want to do this week

  • Dynamics of M31 HII regions using biased Gaia astrometry
  • Star cluster properties accounting for small field correlations

What I would like to learn this week

  • Estimating Gaia’s small field of view correlations
  • Feedback on Gaia mock and GDR2.
  • Crossmatching catalogs including SED information

I Can help with

  • Gaia data, crossmatch & data query helpdesk
  • Gaia Mock / Gaia classification & APs
  • GDR3 BP/RP spectra

Max-Planck Institute

for Astronomy



LV in gas

Interested in:

  • Large scale [G/g]alactic structure. Impact of spirals/bars/companions on ISM/SF processes.

Aim to do:

  • Look at galactic scale velocity fields, how they compare to sims. with different asymmetries/underpinning physics.

Specific knowledge of:

  • Hydro+N-body simulations of galaxies, ISM physics.

Would be keen to know more about:

  • Any aspect of the obs. data really
    (not touched it before!), phase spirals,
    models people are desperate in need of.

...What I don’t want to talk about:

  • Brexit. Please... just let it end.

Do ISM features align 
with any stellar pops?

ISM in
a spiral

Makes some stars...

Alex Pettitt 


Kareem El-Badry (UC Berkeley)


  • What’s going on with wide binary luminosity ratios?
  • Hardening of close binaries in hierarchical triples
  • Test MOND with wide binaries

Bring: binaries, white dwarfs, cosmological simulations, enthusiasm, short attention span

Learn: how to use Gaia as a time-domain survey

Plan to do: Look at known streams in Gaia - measure proper motions, map density, look for extensions in RR Lyrae

Want to learn: More about Gaia systematics, RR Lyrae, reliable density mapping of streams

Bringing: Experience working with DES data, cross-matched dataset, tools for working with streams, experience with stream detection, photometric filtering, proper motion measurement

Want to discuss: Dark matter constraints with streams, differences in globular cluster/dwarf stream populations

Nora Shipp (UChicago)

Emily Cunningham (UCSC)

What I want to do: Look for spatial variation of kinematic properties in the halo with RR Lyrae

What I want to learn: Modeling Gaia systematics; computationally efficient Bayesian inference methods for use with large datasets

What I bring: Expertise in proper motions with HST; spectroscopic analysis; Bayesian inference (incl. hierarchical and mixture modeling)

What I’d like to discuss: Methods for combining multiple datasets; chemodynamics; data-model comparison tools

David Mykytyn (New York University)

What I want to do: *joint with Alex Malz (NYU; he is remote due to impending thesis defense but will Skype in when possible)

  • Improve HR Diagrams for open clusters by identifying and correcting double stars, with the goal of creating a fully probabilistic model for HRD

What I want to learn:

  • A lot more about good models for HRD and also some stellar models that could be combined?
  • Stuff about open clusters? -> What generates the HRD for clusters

What I bring:

  • A lot of knowledge about Gaussian Processes, especially for time-series analysis. Some crazy ideas about using GPs to speed up monte carlo, or even to get better information out of simulations (keywords: Multifidelity Monte Carlo, metamodels/emulators/simulators/etc.)

(Want to get at what 1801.08547 marginalized over)

[Widmark, et. al 2018]

(First stab at PGM)

Ana Bonaca

Center for Astrophysics

Harvard & Smithsonian

Do: constrain the orbit of a possible perturber of the GD-1 stream based on the kinematics of the perturbed region

Bring: Python3 API for C, expertise in the detection and modeling of structures in the stellar halo
Discuss: dating accretion events based on their structure in the space of conserved orbital properties

> Discuss:
- (Passively): DF modeling in action-angle space; inferring MW dust maps with DR2 + MA, age-abundance relations, realistic pipeline for time-series data; zoom-in simulations;

- (
Passionately): outline of a SOTA analysis, hierarchical inference, banish closed-form likelihoods?

(Brown U.)

> Intend to:
- (Warmup) DR2-APOGEE/SDSS x-matched data-sets to study chemo-dynamic properties of velocity ‘substructure’ (h/t: Myeong+’18, TCR’18).

- Develop criteria for qualifying stellar population in a given volume patch as phase-mixed (h/t: BMH’09).

> Experience:
- with DR2 data and selection function based on gaia_tools (Bovy’16);

particle physics: indirect and direct DM detection; cooling rates for dissipative DM.

- (Audaciously): Explore disequilibria with a semi-analytic forward modeling approach using simulations; toy n-body code that includes DM self-interactions.

Semyeong Oh

Institute of Astronomy, Cambridge

I am doing:

kinematic modelling of a cluster

- evidence beyond small (isotropic) dispersion?

I want to learn about:

    • stellar binaries and clusters
    • hierarchical inference and clustering
    • future data

I bring experience with:

Gaia data access and exploration and

making interactive visualizations

Joel C. Zinn

Ohio State University

What I want to do:

Explore TESS-K2-Gaia synergy

What I want to learn more about:

Binaries in Gaia

Gaia parallax systematics

I bring experience with:

Parallaxes beyond ~2-3kpc with red giants, asteroseismology, stellar models, APOGEE, Kepler, K2

Chervin F.P Laporte (University of Victoria / CITA)

DO 1) Finish paper from last year’s Sprint. 2) Test+Map PS-spiral beyond 10 kpc without WEAVE or 4MOST with RC and a model to generate RVs complementing 5D data.

LEARN Bayesian inference methods, data driven techniques, adaptive smoothing/filterning methods, AGAMA.

BRING My pre-Gaia DR2 N-body models of Sgr impacting disc (free data). Useful for anyone doing disc-kinematics/bar kinematics? Familiar with studying kinematic substructure in SN, i.e. happy to help people (e.g. Elena’s team on Arcturus) if I can/it’s cool with y’all.

Existence of moving groups is not a physical explanation for the origin of the PS-spiral.” Happy to discuss/philosophise with Anthony Brown (maybe do a project?). Analogy: If I put re-assemble KFC chicken pieces (drum, breast, wings) into something looking like a chicken it doesn’t mean that KFC explains why chickens exist.

Pre-Gaia simulations

Gaia DR2



Andreea Font (Liverpool John Moores U., UK)

What I want to do:

Look for substructure signature in the Solar neighborhood using various tracer stars.

Compare with results of cosmological simulations. Think about implications for dark matter detection.

What I want to learn:

Combining different catalogues (Gaia, RAVE, APOGEE).

Modeling Gaia systematics.

Knowledge of:

hydro-dynamical simulations, chemo-dynamical models of the Milky Way and dwarf galaxies.

Robyn Sanderson



Doing: evaluating basis-expansion models of the Latte halos for orbit studies, prep for public release of models

Learning: how well we need to represent the MW to study its orbit structure; what else people want from mock observations

Sharing: the ananke mock catalogs, dynamics expertise generally

Philip Chang (University of Wisconsin - Milwaukee, Flatiron Institute)

What I want to do: See what everyone is up to; extract physics from test particle simulations.

What I want to learn: am currently GAIA curious - ready to take the next step.

What I bring: Expertise in theoretical and computational astrophysics; some experience in test particle dynamics; a bit more in SPH/Moving-mesh/Eulerian hydro.

What I want to discuss: Phase space mixing of stars, perturbation theory, etc.

2019 SB Gaia Sprint pitch slides - Google Slides