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tests:astropars:challenge1 [2014/10/31 13:35] – randraetests:astropars:challenge1 [2022/10/24 12:26] (current) – external edit 127.0.0.1
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 ====== Challenge 1: Moving groups ======  ====== Challenge 1: Moving groups ====== 
 ===== Objectives ===== ===== Objectives =====
-* Test our ability to identify known young moving groups in velocity space as a +  * Test our ability to identify known young moving groups in velocity space as a function of distance and RVS precision. 
-function of distance and RVS precision. +  * Investigate Gaia-like data, to quantify the expected errors and reveal new methods for identifying groups with accurate distance information
-* Investigate Gaia-like data, to quantify the expected errors and reveal new methods +
-for identifying groups with accurate distance information+
  
-YOUNG MOVING GROUPS+===== YOUNG MOVING GROUPS =====
  
 There are around a dozen young (<100 Myr) sparse moving groups known within the There are around a dozen young (<100 Myr) sparse moving groups known within the
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 (Zuckerman & Song 2004) around the solar peculiar motion. (Zuckerman & Song 2004) around the solar peculiar motion.
  
 +{{:tests:uv_groups.png|}}
  
 Unlike open clusters, association members are very sparse, with their nearest Unlike open clusters, association members are very sparse, with their nearest
 stellar neighbours highly unlikely to be group members. stellar neighbours highly unlikely to be group members.
 +
 +{{:tests:groupc_xy.png|}}
 +{{:tests:groupc_xz.png|}}
 +
  
  
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 over-densities in distance-velocity space (e,g, near U=0 km/s,V=0 km/s). over-densities in distance-velocity space (e,g, near U=0 km/s,V=0 km/s).
  
 +{{:tests:groupc_uv_.png|}}
  
 However, it’s necessary to consider full 3D velocities, as the over-densities are However, it’s necessary to consider full 3D velocities, as the over-densities are
 not always apparent in some projections: not always apparent in some projections:
  
 +
 +{{:tests:groupc_uw_.png|}}
 +{{:tests:groupc_uwmemb_.png|}}
  
 This could obviously be automated with well-known clustering methods.  This could obviously be automated with well-known clustering methods. 
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 km/s at these distances and spectral types: km/s at these distances and spectral types:
  
 +{{:tests:groupc_rverr.png|}} 
 +{{:tests:groupc_rv.png|}}
  
 This has the effect of smearing out the UVW over densities, reducing their contrast This has the effect of smearing out the UVW over densities, reducing their contrast
 over the background field stars.  over the background field stars. 
 +
 +
  
 Young stars are typically several magnitudes above the main sequence and well Young stars are typically several magnitudes above the main sequence and well
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-NEXT STEPS+===== NEXT STEPS =====
  
-* What about log(g)? Is there sufficient information in the BP/RP spectra to select+  * What about log(g)? Is there sufficient information in the BP/RP spectra to select
 low-gravity objects? low-gravity objects?
  
-* (Re-)defining empirical samples of young stars in Gaia photometric/astrometric system+  * (Re-)defining empirical samples of young stars in Gaia photometric/astrometric system
  
 Most of the scatter in the CMD and phase space plots above is due to the uncertain Most of the scatter in the CMD and phase space plots above is due to the uncertain
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 with confirmatory RVs and youth indicators from ground-based spectroscopy. with confirmatory RVs and youth indicators from ground-based spectroscopy.
  
-FAKE GROUP GENERATOR+===== FAKE GROUP GENERATOR =====
  
 Probably very instructive to quickly code up a package to sample “perfect” IMFs and Probably very instructive to quickly code up a package to sample “perfect” IMFs and
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 convolved with realistic Gaia errors and embedded in GUMS samples to test our convolved with realistic Gaia errors and embedded in GUMS samples to test our
 methods for identifying groups.  methods for identifying groups. 
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tests/astropars/challenge1.1414762522.txt.gz · Last modified: 2022/10/24 12:26 (external edit)