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Karoline's ISM*@ST Intro Talk

Karoline's ISM*@ST Intro Talk

Karoline Gilbert

April 13, 2020
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  1. THE POWER OF RESOLVED STARS FOR REVEALING THE HISTORY OF

    NEARBY GALAXIES AKA AN INTRODUCTION TO WHAT MOTIVATES ME KAROLINE M. GILBERT Image credit: Robert Gendler SPACE TELESCOPE SCIENCE INSTITUTE
  2. How did nearby galaxies and galaxy groups grow and evolve

    — in detail? How can we translate detailed reconstructions of nearby galaxy evolution into meaningful insights about galaxy formation and evolution in the broader universe? THE BIG QUESTIONS THAT MOTIVATE ME:
  3. ANDROMEDA AND ITS SATELLITES (DWARF) GALAXIES IN THE LOCAL UNIVERSE

    PLANNING FOR THE FUTURE DDO 68 WHERE I WORK
  4. THE POWER OF RESOLVED STARS FOR REVEALING ANDROMEDA’S MERGER HISTORY

    SURVEYS OF RESOLVED STARS IN M31 PAndAs Starcount Map (McConnachie et al. 2018) M31$ N185$ N147$ M33$ 30$kpc$ 90$kpc$ 150$kpc$ 60$kpc$ N$ E$ M31$dSphs$ Giant$Southern$ Stream$ M31$Halo$Fields$ PAndAS$M31$Map$ (McConnachie$et$al.)$ Dwarf$Galaxy$Fields$ SPLASH Fields PHAT (Dalcanton et al. (+KM G) 2012
  5. PAndAs Starcount Map (McConnachie et al. 2018) Inner Halo: In

    Situ Population • Constraints on Formation Avenues • Relative importance of in situ and accretion Mass of Halo: Comparing Observations with Simulated Halos Tidal Debris Features: Recent Accretion Events • Stellar properties of recently accreted satellites • Modeling of collision: time of accretion, mass of progenitor and host galaxy • Orbits of satellites Global Properties: Accretion History • Luminosity Function, Time of Accretion of destroyed dwarf galaxy population • Relative Importance of major/minor mergers over time Key Observables: stellar density, stellar velocities, chemical abundances, star formation histories
  6. DECIPHERING ANDROMEDA’S MERGER HISTORY: RECENT ACCRETION EVENTS Line of sight

    velocity distributions of stars resolve spatially overlapping streams discover faint streams identify connections between photometric substructures help tease the needles (M31 stars) out of the haystack (contaminants) CONSTRAIN THE ORBITS OF PROGENITORS K. M. Gilbert et al. 2009b K. M. Gilbert et al. 2009b Velocity Distribution (km/s) SPECTROSCOPY IS CRUCIAL FOR RECONSTRUCTING RECENT ACCRETION EVENTS M31$ N185$ N147$ M33$ 30$kpc$ 90$kpc$ 150$kpc$ 60$kpc$ N$ E$ M31$dSphs$ Giant$Southern$ Stream$ M31$Halo$Fields$ PAndAS$M31$Map$ (McConnachie$et$al.)$ Dwarf$Galaxy$Fields$
  7. DECIPHERING ANDROMEDA’S MERGER HISTORY: SPECTROSCOPY SPLASH SPECTROSCOPIC SURVEY OF ANDROMEDA

    Over 20,000 M31 RGB spectra in disk, halo, and dwarf galaxies Medium-resolution spectra of more than 1500 M31 halo stars More than 50 spectroscopic fields throughout M31’s stellar halo roughly 1 in 100 targets in outermost halo fields are M31 stars M31$ N185$ N147$ M33$ 30$kpc$ 90$kpc$ 150$kpc$ 60$kpc$ N$ E$ M31$dSphs$ Giant$Southern$ Stream$ M31$Halo$Fields$ PAndAS$M31$Map$ (McConnachie$et$al.)$ Dwarf$Galaxy$Fields$ M31’s Halo Dwarf Galaxy SPLASH Fields Keck Telescopes
  8. DECIPHERING ANDROMEDA’S MERGER HISTORY: SPECTROSCOPY SPLASH SPECTROSCOPIC SURVEY OF ANDROMEDA

    Characterized tidal debris features Measured global halo properties: surface brightness, photometric metallicity, and velocity dispersion profiles to ≥100 kpc M31$ N185$ N147$ M33$ 30$kpc$ 90$kpc$ 150$kpc$ 60$kpc$ N$ E$ M31$dSphs$ Giant$Southern$ Stream$ M31$Halo$Fields$ PAndAS$M31$Map$ (McConnachie$et$al.)$ Dwarf$Galaxy$Fields$ M31’s Halo Dwarf Galaxy SPLASH Fields Keck Telescopes Gilbert et al. 2012, 2014, 2018 Gilbert et al. 2007, 2009a,b
  9. DECIPHERING ANDROMEDA’S MERGER HISTORY: INNER HALO AND DISK TRACING THE

    STELLAR HALO INWARDS Combine contiguous spectroscopic and photometric datasets SPLASH: spectra of > 5000 M31 Stars PHAT: imaging of > 100 Million M31 stars Model M31’s structural components from 4 kpc; Investigate dynamics as a function of stellar age Significant rotation in inner spheroid Evidence for a population of former disk stars heated into halo Increasing asymmetric drift with age: evidence M31’s stellar disk dynamically heated over time Dorman et al. (+KMG) 2013 Dalcanton et al. (+KMG) 2012 M31$ N185$ N147$ M33$ 30$kpc$ 90$kpc$ 150$kpc$ 60$kpc$ N$ E$ M31$dSphs$ Giant$Southern$ Stream$ M31$Halo$Fields$ PAndAS$M31$Map$ (McConnachie$et$al.)$ Dwarf$Galaxy$Fields$ Dorman et al. 2012, 2013, 2015; Quirk et al. 2019
  10. Global Properties: Accretion History • Bulk of stellar mass: one

    to a few relatively massive (>109 M⊙ ) accretion events • M31 likely experienced a prolonged accretion history. May require many recent low-mass accretions at large radii. • M31 likely has a more massive dominant progenitor and larger accreted stellar halo than the typical MW-mass galaxy SIMULATIONS HAVE NOW PRODUCED GSS MORPHOLOGY WITH MERGER MASS RATIOS RANGING FROM 2:1 TO 300:1 PAndAs Starcount Map (McConnachie et al. 2018) Inner Halo: In Situ Population • Inner region of M31’s halo has a significant population of stars that once belonged to the disk • Multiple lines of evidence indicate an active recent accretion history impacting the disk Tidal Debris Features: Recent Accretion Events • Giant Stellar Stream related debris found throughout the inner halo • Minor merger simulations indicate an LMC to M33 mass progenitor disrupted ~750 Myr ago • Modeling full halo velocity distribution: improved constraints on substructure kinematics and uncertainties For more, see my STScI May 2019 colloquium
  11. DECIPHERING ANDROMEDA’S MERGER HISTORY: CHEMICAL ABUNDANCES ABUNDANCES CAN BREAK THE

    DEGENERACY LUMINOSITY FUNCTION OF ACCRETED SATELLITES TIME OF ACCRETION Image Credit Sanjib Sharma Stellar Surface Density Metallicity [Fe/H] Alpha Element Abundances [ /Fe] Stellar luminosity Time of infall Stellar luminosity plus time since disruption e.g., K. M. Gilbert et al. 2009a, Lee et al. 2015
  12. DECIPHERING ANDROMEDA’S MERGER HISTORY: CHEMICAL ABUNDANCES ALPHA ABUNDANCES OF STREAMS

    CORRELATE WITH TIME OF INFALL [ /Fe] provides a clock First Star Formation Core Collapse SNe – element rich ejecta (e.g., Si, Ti, Ca, Mg) Type Ia SNe – Fe rich ejecta [ /Fe] [Fe/H]
  13. DECIPHERING ANDROMEDA’S MERGER HISTORY: CHEMICAL ABUNDANCES ALPHA ABUNDANCES OF STREAMS

    CORRELATE WITH TIME OF INFALL [ /Fe] provides a clock [ /Fe] vs. [Fe/H] encodes the efficiency of star formation over time First Star Formation Core Collapse SNe – element rich ejecta (e.g., Si, Ti, Ca, Mg) Type Ia SNe – Fe rich ejecta [ /Fe] [Fe/H]
  14. M31$ N185$ N147$ M33$ 30$kpc$ 90$kpc$ 150$kpc$ 60$kpc$ N$ E$

    M31$dSphs$ Giant$Southern$ Stream$ M31$Halo$Fields$ PAndAS$M31$Map$ (McConnachie$et$al.)$ Dwarf$Galaxy$Fields$ M31$ N185$ N147$ M33$ 30$kpc$ 90$kpc$ 150$kpc$ 60$kpc$ N$ E$ M31$dSphs$ Giant$Southern$ Stream$ M31$Halo$Fields$ PAndAS$M31$Map$ (McConnachie$et$al.)$ Dwarf$Galaxy$Fields$ Deep DEIMOS spectra completed in progress DECIPHERING ANDROMEDA’S MERGER HISTORY: CHEMICAL ABUNDANCES BUILDING A STATISTICAL CENSUS OF CHEMICAL ABUNDANCES Existing SPLASH data Coadd low SNR spectra Mean [Fe/H], [ /Fe] abundances New Spectroscopic Campaign Obtain deep data in strategic dSph and halo fields Distributions of [Fe/H], [ /Fe] abundances M31’s halo: from 4 stars to 240 stars Extension of spectral synthesis method to lower resolution (R~3000) Jennifer Wojno Ivanna Escala Evan Kirby NSF AST-1614569 (PI K. M. Gilbert) and AST-1614081 (PI Kirby) M31$ N185$ N147$ M33$ 30$kpc$ 90$kpc$ 150$kpc$ 60$kpc$ N$ E$ M31$dSphs$ Giant$Southern$ Stream$ M31$Halo$Fields$ PAndAS$M31$Map$ (McConnachie$et$al.)$ Dwarf$Galaxy$Fields$ Escala et al. 2019 Gilbert et al. 2019, Escala et al. 2020, Kirby et al. 2019, + Wojno et al. subm.
  15. DECIPHERING ANDROMEDA’S MERGER HISTORY: CHEMICAL ABUNDANCES K. M. Gilbert et

    al., 2019 FIRST ALPHA ABUNDANCES IN GSS GSS experienced higher efficiency of star formation than surviving M31 dwarf satellites [Fe/H] [ /Fe] And V, VII: Kirby, K. M. Gilbert et al., subm. N185: Vargas et al. 2014 PAndAS Starcount Ma (McConnachie et al. 20 50 kpc 100 kpc And I And III And II And X f130 H13s f207 GSS M33 M31$ N185$ N147$ M33$ 30$kpc$ 90$kpc$ 150$kpc$ 60$kpc$ N$ E$ M31$dSphs$ Giant$Southern$ Stream$ M31$Halo$Fields$ PAndAS$M31$Map$ (McConnachie$et$al.)$ Dwarf$Galaxy$Fields$
  16. DECIPHERING ANDROMEDA’S MERGER HISTORY: CHEMICAL ABUNDANCES K. M. Gilbert et

    al., 2019 FIRST ALPHA ABUNDANCES IN GSS GSS experienced higher efficiency of star formation than surviving M31 dwarf satellites And than Sagittarius and the Magellanic Clouds PAndAS Starcount Ma (McConnachie et al. 20 50 kpc 100 kpc And I And III And II And X f130 H13s f207 GSS M33 M31$ N185$ N147$ M33$ 30$kpc$ 90$kpc$ 150$kpc$ 60$kpc$ N$ E$ M31$dSphs$ Giant$Southern$ Stream$ M31$Halo$Fields$ PAndAS$M31$Map$ (McConnachie$et$al.)$ Dwarf$Galaxy$Fields$ [Fe/H] [ /Fe]
  17. ANDROMEDA AND ITS SATELLITES DWARF GALAXIES IN THE LOCAL UNIVERSE

    PLANNING FOR THE FUTURE DDO 68 WHERE I WORK
  18. DWARF GALAXIES AS PHYSICAL LABORATORIES STAR FORMATION IN LOW MASS,

    LOW METALLICITY ENVIRONMENTS The evolution of low mass galaxies is strongly responsive to a wide array of physical processes: Reionization External Processes ram pressure stripping tidal stripping, stirring environmental triggering of star formation Dwarf-Dwarf interactions and mergers Internal Processes (stellar feedback) some unique to low-mass environment DDO 68 Fornax IC1613
  19. DWARF GALAXIES AS PHYSICAL LABORATORIES OBSERVATIONAL CONSTRAINTS How to tease

    out internal from environmental effects? Color-magnitude diagrams global, spatially resolved SFHs structure: stellar density profiles, radial gradients, evidence for interactions Internal stellar kinematics 3-D motions DDO 68 Fornax IC1613
  20. THE POWER OF RESOLVED STARS FOR REVEALING TRIANGULUM’S HISTORY from

    D’Souza and Bell 2018b ~200 kpc from M31, M* ~ 3x109 M⊙ TRIANGULUM (M33)
  21. PHAT + SPLASH EXTENSION TO M33: RESOLVED STELLAR SPECTROSCOPY AND

    HST IMAGING Disk kinematics as a function of stellar age Quantitative comparison with tracers of gas disk Chemo-dynamical analysis of older stellar populations Does M33 have a stellar halo? What forces have driven the disturbances in the stellar and gas disks? THE POWER OF RESOLVED STARS FOR REVEALING TRIANGULUM’S HISTORY NSF AST-1909066 (PI K. M. Gilbert) and AST-1909759 (PI P. Guhathakurta) Amanda Quirk Raja Guhathakurta PI Dalcanton; GO-14610 Proposed Existing Literature
  22. McConnachie et al. 2006 GO-10190, M33-DISK1 GO-10190, M33-DISK2 FIRST RESULTS:

    DEFINITIVE EVIDENCE OF A WIDESPREAD KINEMATICALLY HOT COMPONENT K. M. Gilbert et al., in prep. >800 RGB stars; ≳30% in a ≳50 km/s component PI Dalcanton; GO-14610 Velocity Offset from HI Disk Model Probability Younger stars RGB stars HI Disk Model: Kam et al., 2017 THE POWER OF RESOLVED STARS FOR REVEALING TRIANGULUM’S HISTORY
  23. DWARF GALAXIES AS PHYSICAL LABORATORIES OBSERVATIONAL CONSTRAINTS How to tease

    out internal from environmental effects? Color-magnitude diagrams global, spatially resolved SFHs structure: stellar density profiles, radial gradients, evidence for interactions Internal stellar kinematics 3-D motions DDO 68 Fornax IC1613
  24. RESOLVED STELLAR POPULATION STUDIES IN LOCAL VOLUME DWARFS FROM ANGST

    AND ANGRRR TO LUVIT — ACS Nearby Galaxy Survey Treasury volume-limited sample of 69 galaxies within 3.5 Mpc plus M81 and NGC 253 groups (ACS/WFC and WFPC2) available on MAST Archive of Nearby Galaxies: Reduce, Reuse, Recycle ~700 ACS/WFC and WFPC2 datasets of ~150 galaxies within 5 Mpc homogeneously reduced with ANGST reduction pipelines (precursor to PHAT pipeline) within 3.5 Mpc on MAST; for remainder see me HST IMAGING SURVEYS OF THE LOCAL VOLUME ANGST Sample, Dalcanton et al. 2009
  25. RESOLVED STELLAR POPULATION STUDIES IN LOCAL VOLUME DWARFS LUVIT —

    LOCAL ULTRAVIOLET IMAGING TREASURY UV observations with WFC3/UVIS in 22 dwarf galaxies on edge of LG and in LV (GO-15275) combined with archival broad-band imaging 4- or 6-band (UV-optical-IR) imaging Targets have wealth of ancillary data in other wavelengths Stellar SED fitting (BEAST): Teff , Lbol , AV , RV Improved constraints on recent SFH - spatially resolved (60 pc at 2.5 Mpc) maps of recent SF over last 300 Myr, time resolution better than all common SFR/stellar age indicators Generate resolved dust maps (MegaBEAST!) Infer unobscured UV flux of every resolved star ….
  26. RESOLVED STELLAR POPULATION STUDIES IN LOCAL VOLUME DWARFS LUVIT —

    LOCAL ULTRAVIOLET IMAGING TREASURY UV observations with WFC3/UVIS in 22 dwarf galaxies on edge of LG and in LV (GO-15275) combined with archival broad-band imaging 4- or 6-band (UV-optical-IR) imaging Targets have wealth of ancillary data in other wavelengths Stellar SED fitting (BEAST): Teff , Lbol , AV , RV Improved constraints on recent SFH - spatially resolved (60 pc at 2.5 Mpc) maps of recent SF over last 300 Myr, time resolution better than all common SFR/stellar age indicators Generate resolved dust maps (MegaBEAST!) Infer unobscured UV flux of every resolved star …. NGC 4214 predicted unobscured FUV GALEX FUV contours Choi et al. 2017 SEE YUMI’S INTRO TALK!
  27. ANDROMEDA AND ITS SATELLITES DWARF GALAXIES IN THE LOCAL UNIVERSE

    PLANNING FOR THE FUTURE DDO 68 WHERE I WORK
  28. 150 kpc 100 kpc 50 kpc THE FUTURE OF RESOLVED

    STAR STUDIES: WIDE FIELDS WIDE FIELD SPECTROSCOPY IN ANDROMEDA CURRENT SPECTROSCOPIC COVERAGE PAndAs Starcount Map McConnachie et al. 2018 K. M. Gilbert & E. Tollerud, Astro2020 white paper Degrees from M31’s Center Degrees from M31’s Center
  29. 150 kpc 100 kpc 50 kpc THE FUTURE OF RESOLVED

    STAR STUDIES: WIDE FIELDS WIDE FIELD SPECTROSCOPY IN ANDROMEDA CURRENT SPECTROSCOPIC COVERAGE PAndAs Starcount Map McConnachie et al. 2018 K. M. Gilbert & E. Tollerud, Astro2020 white paper Degrees from M31’s Center Degrees from M31’s Center
  30. 150 kpc 100 kpc 50 kpc THE FUTURE OF RESOLVED

    STAR STUDIES: WIDE FIELDS WIDE FIELD SPECTROSCOPY IN ANDROMEDA CURRENT SPECTROSCOPIC COVERAGE PAndAs Starcount Map McConnachie et al. 2018 K. M. Gilbert & E. Tollerud, Astro2020 white paper Degrees from M31’s Center Degrees from M31’s Center
  31. 150 kpc 100 kpc 50 kpc THE FUTURE OF RESOLVED

    STAR STUDIES: WIDE FIELDS WIDE FIELD SPECTROSCOPY IN ANDROMEDA CURRENT SPECTROSCOPIC COVERAGE PAndAs Starcount Map McConnachie et al. 2018 K. M. Gilbert & E. Tollerud, Astro2020 white paper McConnachie et al. 2018 Degrees from M31’s Center Degrees from M31’s Center
  32. 150 kpc 100 kpc 50 kpc THE FUTURE OF RESOLVED

    STAR STUDIES: WIDE FIELDS WIDE FIELD SPECTROSCOPY IN ANDROMEDA CURRENT SPECTROSCOPIC COVERAGE POTENTIAL WIDE FIELD MOS SURVEY COVERAGE PAndAs Starcount Map McConnachie et al. 2018 K. M. Gilbert & E. Tollerud, Astro2020 white paper Degrees from M31’s Center Degrees from M31’s Center
  33. THE FUTURE OF RESOLVED STAR STUDIES: WIDE FIELDS WIDE FIELD

    HIGH RESOLUTION IMAGING IN ANDROMEDA Contiguous deep imaging to ancient Main Sequence turnoff will be enabled over significant areas of halo with WFIRST Existing HST imaging to the old Main Sequence Turnoff Brown et al. 2008, 2009 WFIRST Field of View Extended Disk 11 kpc Minor Axis Halo Field 21 kpc 21 kpc Giant Stellar Stream Field 35 kpc K. M. Gilbert & E. Tollerud, Astro2020 white paper
  34. THE FUTURE OF RESOLVED STAR STUDIES: EXPANDED SURVEY VOLUMES LUVOIR

    15m PHAT LUVOIR 9m PHAT WFIRST Resolved RGB imaging of halos M81 Group 3.5 Mpc 30-m MOS Fig. from Weisz & Boylan-Kolchin, Astro2020 white paper
  35. THE FUTURE OF RESOLVED STAR STUDIES: EXPANDED SURVEY VOLUMES STELLAR

    DISKS AND HALOS IN THE LOCAL VOLUME Combination of JWST, 30-m telescopes, WFIRST, and LUVOIR will: Extend current day M31-like studies to galaxies throughout the Local Volume Wide field studies of M31 will be crucial for correctly interpreting the observations JWST WFIRST TMT LUVOIR
  36. MEANWHILE, OUTSIDE OF ASTRONOMY… MY HAPPY PLACES* *In normal times

    YES!! Happy: steep Happier: deep Happiest: steep, deep, trees
  37. MY HAPPY PLACES* *In normal times The blissful beginning of

    a monster 14 day adventure. Yes, there is world class climbing near(ish) Baltimore. MEANWHILE, OUTSIDE OF ASTRONOMY…
  38. WHEN STUCK AT HOME? and So Many (long neglected) hobbies….

    but Netflix is good too. Can always climb the walls… MEANWHILE, OUTSIDE OF ASTRONOMY…