The Milky Way and Resolved galaxies with China Space Station - - PowerPoint PPT Presentation

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the milky way and resolved galaxies with china space
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The Milky Way and Resolved galaxies with China Space Station - - PowerPoint PPT Presentation

Feb 02, 2023 159 likes •660 views

The Milky Way and Resolved galaxies with China Space Station Optical Survey Chao Liu (NAOC) Team members: Jian Gao (BNU), Xiangxiang Xue (NAOC), Jing Zhong (SHAO), Zhou Fan (NAOC), Kefeng Tan (NAOC), Haining Li (NAOC) et al. Advantages for MW

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The Milky Way and Resolved galaxies with China Space Station Optical Survey

Chao Liu (NAOC) Team members: Jian Gao (BNU), Xiangxiang Xue (NAOC), Jing Zhong (SHAO), Zhou Fan (NAOC), Kefeng Tan (NAOC), Haining Li (NAOC) et al.

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Advantages for MW and resolved galaxies

  • High spatial resolution (0.075”/pixel) good for crowd fields
  • Potential for proper motions
  • 3 epochs only with CSS-OS: <1mas@r=24mag (c.f. Z-X. Qi)
  • Or 2 epochs from CSS-OS+Euclid(+LSST)
  • Large sky area coverage (MW is located everywhere)
  • Deep photometry (r~25 mag)
  • Slitless spectroscopy (better stellar parameters)
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SLIDE 3

Virial radius of MW LMC M31 M81 M101 NGC891 Virgo

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SLIDE 4

Parts of the ladder of the universe

  • Stars
  • Star clusters
  • Dwarf galaxies
  • Milky Way
  • Local group
  • Resolved galaxies

a few-10 pc 10-100 kpc 1 Mpc 10 Mpc

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SLIDE 5

Parts of the ladder of the universe

  • Stars
  • Star clusters
  • Dwarf galaxies
  • Milky Way
  • Local group
  • Resolved galaxies

a few-10 pc 10-100 kpc 1 Mpc 10 Mpc

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SLIDE 6

Parts of the ladder of the universe

  • Stars
  • Star clusters
  • Dwarf galaxies
  • Milky Way
  • Local group
  • Resolved galaxies

a few-10 pc 10-100 kpc 1 Mpc 10 Mpc

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SLIDE 7

Parts of the ladder of the universe

  • Stars
  • Star clusters
  • Dwarf galaxies
  • Milky Way
  • Local group
  • Resolved galaxies

a few-10 pc 10-100 kpc 1 Mpc 10 Mpc

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SLIDE 8

Parts of the ladder of the universe

  • Stars
  • Star clusters
  • Dwarf galaxies
  • Milky Way
  • Local group
  • Resolved galaxies

a few-10 pc 10-100 kpc 1 Mpc 10 Mpc

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SLIDE 9

Parts of the ladder of the universe

  • Stars
  • Star clusters
  • Dwarf galaxies
  • Milky Way
  • Local group
  • Resolved galaxies

a few-10 pc 10-100 kpc 1 Mpc 10 Mpc

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SLIDE 10

Parts of the ladder of the universe

  • Stars
  • Star clusters
  • Dwarf galaxies
  • Milky Way
  • Local group
  • Resolved galaxies

a few-10 pc 10-100 kpc 1 Mpc 10 Mpc

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SLIDE 11

Stellar physics

  • Binaries, pulsators, and peculiar stars
  • Evolution of the binary systems is big challenge, which is

related to many interesting topics, e.g. SNIa progenitors, formation history of galaxies, sources of gravitational wave etc.

  • Pulsators (Cepheid, RRLy etc.) can be used as standard

candles

  • Peculiar stars, especially rare stars in the evolutionary track

due to extremely short time scales are critical to understand the full process of the stellar evolution, especially in the very beginning and near-end phases

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SLIDE 12

Belokurov et al. 2016 Scatters of magnitudes in different epochs

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SLIDE 13

Ivezic et al. 2000 RRLy Normal stars

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Goals of stellar physics

  • Identify variables from magnitude differences between 2 epochs
  • e.g. RRLy within 1Mpc (inc. M31)
  • Color index can help to distinguish the types of the variables
  • Eclipse binaries can be identified
  • Accurate distribution of the stellar loci distribution in color-color

space helps to give fraction of binaries

  • Identify rare objects from color-color diagrams
  • e.g. WDs within several 10kpc (inc.LMC/SMC)
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SLIDE 15

Star clusters

  • see Jing Zhong’s talk
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The Milky Way

  • The halo (Xiangxiang,Xue’s talk)
  • The disk: 3D extinction and extinction law at various

sightlines, global structure (size, structural parameters, flare, warp, oscillations (wobbly disk)), kinematics (with PMs only), chemo-kinematics (photometric metallicity or metallicity from slitless spectra)

  • The bulge: Global structure, stellar populations traced by

different types of stars, kinematics and dynamics with PMs

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SLIDE 17

Proposed survey strategy

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Proposed survey strategy

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Proposed survey strategy

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Proposed survey strategy

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SLIDE 21

Proposed survey strategy

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Stellar parameters

  • Basic parameters obtained from photometry and slitless spectra
  • Effective temperature, metallicity, surface gravity (Teff, [Fe/H],

logg). Accuracy: ∆Teff~150K, ∆[fe/H]~0.2-0.3 dex, ∆logg~0.3-0.5 dex for AFGK stars

  • Photometric parallax from multi-band colors calibrated with

Gaia (Absolute magnitudes: MNUV, Mu, Mg, Mr, Mi, Mz, My). Meanwhile, extinctions from relative reddening

  • Proper motions from multi-epoch data (CSS-OS only or

synergy with Euclid and LSST) (𝝂_αcos𝜺, 𝝂_𝜺). Accuracy <1mas@r=24mag

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SLIDE 23

Keller et al. 2007

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SLIDE 24

Keller et al. 2007

v band filter is not only sensitive to metallicity but also to surface gravity!

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SLIDE 25

The Galactic structure learnt from LAMOST survey

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SLIDE 26

The Galactic structure learnt from LAMOST survey

Thin disk Thick disk Bulge/Bar Satellites Tidal streams Dark halo Stellar halo

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SLIDE 27

The Galactic structure learnt from LAMOST survey

Thin disk Thick disk Bulge/Bar Satellites Tidal streams Dark halo Stellar halo

Larger disk Oblate-spherical halo Age variation in warp New tidal streams Flare with young pop.

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SLIDE 28

The halo

5000+ RGB stars from DR3 with [Fe/H]<-1dex and MK<-4

q is variable with r ∝r-5.0 Liu et al. 2017 Xu, LC et al. 2017 q r lnν ln r

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The disk

  • The disc is more extended
  • At R=19kpc, the fraction of disc
  • pop. is still ~10%
  • No truncation, break, bend-up

feature is found in the outer disc

  • It simply follow an exp. profile and

smoothly transition to the halo

Liu et al. 2017

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SLIDE 30

Xu et al. 2015

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SLIDE 31

The Bulge

Howes et al. 2015 Ness et al. 2016 Lecureur et al 2007

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SLIDE 32

The Bulge

Vasquez et al. 2013 Cao et al. 2013

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SLIDE 33

Goals of the Milky Way science

  • Detect the border of the Milky Way

halo/disk

  • Map the shape of the halo
  • Global structures,

substructures

  • Derive the 3D structural

parameters of the Galactic disk

  • Scale heights, scale length
  • oscillations, flare, warp
  • The shape of the bulge
  • Multiple populations
  • With PMs
  • Dynamical mass of the Galaxy

and the disk mass of the MW

  • chemo-dynamical evolution of

the Milky Way

  • Tidal substructures in the halo
  • kinematics/dynamics of the

bulge/bar

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SLIDE 34

Resolved galaxies

  • Well discriminate individual stars from globular clusters in

very nearby galaxies (LMC/SMC/M31 etc)

  • Wide fields allow an efficient imaging for the whole nearby

galaxies, including disks, bulges, and stellar halos (outskirts)

  • Multi-band photometry good for trace different

populations

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Studies on Globular clusters in the Local Group(M31/M33, M81/M82, etc.)

  • 1. Discover more GCs

Discovering more GCs, especially in the halo of galaxies, can provide important clues on the accretion histories of the host galaxies. The recent large project PHAT done by Hubble telescope only covers the inner disk of M31. PAndAS (CFHT)

  • 2. Multiple population studies of GCs

Multiple population in GCs have been widely studied in the Milky Way, LMC and SMC. Detailed studies on M31/M33 GCs could enhance our understanding of the chemical enrichment and formation histories of these clusters. Y~0.38 Y~0.24 Y~0.28

NG NGC2808

Piotto et al. (2007)

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SLIDE 36

Studies on Globular clusters in the Local Group

  • 3. Stellar population studies of GCs

Stellar population, including age and metallicity, can be effectively used to constrain the formation and evolution histories of the host galaxies. The most reliable method is fitting the isochrones to the CMDs of GCs, but only few GCs in M31/M33 have observations well enough to do such work.

  • 4. Structural studies of GCs

Spatial structures and dynamics of GCs is of great importance for understanding their formation condition, dynamical evolution, and discruption within the environment of their galaxies. This work has been done for few GCs in M31 (< 100) and M33 (< 10) .

Williams & Hodge (2001) K66, W, S represent different dynamical models; F555W/F814W are filters in HST . Wang et al. (2013)

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Stellar Astrophysics in M31

[Fe/H], Age and Mass Tanaka et al. (2010)

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SLIDE 38

Stars in nearby galaxies

Karachentsev et al. 2013

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SLIDE 39

A deep census of the satellite galaxies of the MW and M31

  • Vast polar structure (VPOS)?
  • Missing satellite problem or not?
  • Constrain the nature of the dark matter particle
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SLIDE 40

2 epochs HST obs. between 5-7.5 yr

Sohn et al. 2012

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SLIDE 41

The proper motion of M31

  • 800kpc, 200km/s==>0.05mas/yr
  • 10/20/30 years：0.5/1.0/1.6mas
  • It is possible to be detected by combining with

HST(~0.02”/pixel), Euclid and PAndAS（0.187”/ pixel+0.7”seeing）

  • Proper motions of the globular clusters in M31

can also be derived by combining with HST archive data

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SLIDE 42

Goals of resolved galaxies

  • Systematic survey for globular clusters in nearby galaxies,

better address the multi-population issue in GCs

  • Formation and evolution of the nearby galaxies will be

studied in the similar way to the MW, i.e. by using individual stars

  • Proper motions help to reveal the kinematic/dynamic

features of the local group

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SLIDE 43

Interstellar dust/extinction

  • Diffused region: extinction law covering from NUV to

near infrared in different systems (MW, LMC/SMC, M31, and nearby resolved galaxies)

  • Dark clouds: combine with infrared photometric data

(WISE etc.) in the bulge direction, LMC/SMC etc.

  • Goals: extinction laws in different environments:

diffused/dark regions, MW, LMC/SMC/other galaxies

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SLIDE 44

Drain 2003

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SLIDE 45

Nataf et al. 2013 Toward the bulge (Baade window)

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SLIDE 46
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SLIDE 47
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SLIDE 48

Summary

  • Stars: variables, binaries (field), peculiar stars; stellar evolution (especially binary systems),

identify stellar probs for the galaxies

  • Star clusters: binaries, populations, internal kinematics (with PMs), GCs in other nearby

galaxies (LMC/SMC/M31/M33/etc.); dynamical evolution of star clusters, binary evolution, the multiple-population problem, IMF in various environments

  • The Milky Way: star counts, kinematics (with PMs), the border of the Galaxy; complete

shape of the Galaxy, total mass of the DM halo/disk, formation history and dynamical properties of the bulge/bar, evolution of the MW

  • The local group: kinematics/dynamics of the members of the local groups; dynamical

evolution of the local group (does it bound system?)

  • The resolved galaxies: well cover LMC/SMC, M31/M33, and other nearby galaxies;

Interstellar laws in various environments, structure and evolution of the nearby galaxies

Considering their versatility and fundamentally importance in astrophysics, the MW/resolved galaxies sciences should not be a byproduct of CSS- OS, but one of the equivalently important main goals. In this sense, the survey should be tuned, to some extents, to meet the requirements from the MW/ resolved galaxies as well as the large scale structures and cosmology