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G.J. Stacey Cornell University. Theme IV: Nearby Galaxies and the Galactic Center. Team Members. Gordon Stacey (Cornell)Formal Lead Science: Far-IR and submm spectroscopy of galaxies, Galactic starformation regions, Galactic Center Experience: KAO/ISO/JCMT – CSO - PowerPoint PPT Presentation
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Theme IV: Nearby Galaxies Theme IV: Nearby Galaxies and the Galactic Centerand the Galactic Center
G.J. Stacey
Cornell University
Team MembersTeam Members
Gordon Stacey (Cornell) Formal Lead Science: Far-IR and submm spectroscopy of galaxies,
Galactic starformation regions, Galactic Center Experience: KAO/ISO/JCMT – CSO Investments: SOFIA (FORCAST/SAFIRE) Unique Strength: Submm lines, Instrumentation
Bill Vacca (USRA) SOFIA Lead Science: UV/Optical/Near IR spectroscopy & photometry
galaxies, star clusters, massive stars Experience: HST/Keck/IRTF/Gemini/Spitzer Investments: SOFIA Unique Strength: Optical studies, Stellar Populations
Team MembersTeam Members
Sue Madden (CEA/Saclay) Science: Mid/far-IR and spectroscopy and photometry of
galaxies , Galactic starformation regions, Galactic Center Experience: KAO/ISO (LWS/ISOCAM) Investments: Herschel (SPIRE/PACS) Unique Strength: Dwarf Galaxies, Dust continuum
Mark Morris (UCLA) Science: Multi-wavelength studies of the Galactic Center Experience: KAO/VLA/HST/Keck/Chandra/Spitzer Investments: SOFIA Unique Strength: Galactic Center
Team MembersTeam Members
Linda Tacconi (MPE) Science: Multi-wavelength spectroscopy of active galaxies
AGN/high z galaxies Experience: FCRAO/JCMT/VLT/ISO(SWS) Spitzer IRAM
Interferometer Investments: Herschel (PACS) Unique Strength: Molecular gas in high z galaxies
Mark Wolfire (Maryland) Science: Theory – PDR/XDR and HII region modeling – Galactic
starformation regions, Galactic Center, galaxies Experience: KAO/ISO/Spitzer Investments: SOFIA Unique Strength: Theory, modeling
ActivitiesActivities
Team assembled in April/MayFirst Telecon in late May
Discussion of scope of our assignment – where do we fit in?
Discussion of science topicsDiscussion of timelinesTelecons scheduled for Wednesdays at noon
eastern time
Where do we fit in?Where do we fit in? Whitepaper generated by a group led by Erick Young
Two page section on extragalactic work January 2008 AAS SOFIA Workshop Whitepaper
(Bob Gehrz-led)4 page section on extragalactic and Galactic
Center work with SOFIA 2005 SOFIA Science Cases (Tom Greene)
Section on Galactic CenterSection on HAWC observations of the distant
UniverseSection on nearby Galaxies
How do we fit in?
Goals/ScheduleGoals/Schedule Create a list of science topics well
addressed by SOFIA Define the unique capabilities of SOFIA
within its current instrumentation Within the science list, compare the
capabilities of SOFIA and contemporaneous facilities (e.g. Herschel) and near future facilities (e.g. JWST) How can second generation SOFIA
instruments tip the balance Refine science topics Prepare document Prepare PPT slides
June 18
July 16
August 13
October 1
Example: Nearby GalaxiesExample: Nearby Galaxies
Stellar evolution
Diffuse interstellar gas
Dense interstellarclouds
Star formation
Windsstellar explosions
Stellar remnants
Primordial gas
Cooling, contractionchemistry
Contraction,gravitational instability
H, He, C+, O
H2, He, CO
Interstellar Gas and Interstellar Gas and the Stellar Life Cyclethe Stellar Life Cycle
Example: Nearby Spiral GalaxiesExample: Nearby Spiral Galaxies Morphologies
Elemental abundances Dust parameters
Requires high spatial resolution
Key elements Wide-field mapping –
mapping speed Spatial registration
between lines/continuum etc.
Sensitivity Variety of lines available
and dust SEDs
SAFIRE FOV
Beam at [OI]
SOFIA StrengthsSOFIA Strengths Mapping capabilities
Large field of view for cameras (e.g. FORCAST 33’ FOV, SAFIRE FPI ~ 2.75.3’ FOV)
What are the relative mapping speeds of SOFIA/Herschel for typical nearby galaxies – SOFIA efficiencies twice as high!
Large chopper throw essential for mapping large nearby galaxies (SOFIA 10’ vs. 6’ for Herschel)
How does this effect Hershel source list? Resolving power uniquely high between 5 to 28 and
100 to 700 m (SAFIRE, FPI) Advantages of EXES and SAFIRE?
Resolved lines to distinguish ISM components
SOFIA StrengthsSOFIA Strengths Wavelength coverage
9 octaves of wavelength coverage (1 to 700 m) Post-Spitzer near unique coverage from ~5 m (until
JWST) through 60 m (Herschel) Covers the peak of dust SED in starburst galaxies Host of lines from 5 to 60 m including (post Spitzer)
SOFIA unique lines:[SIII] (33 m), [SiII] (35 m), [NeIII] (36 m), [OIII] (52 m),
[NIII] (57 m), in the 30 to 60 m band Resolve and map far-IR lines with SAFIRE including
unique ones beyond 200 m:[NII], [CII] [OI], mid and high J CO (but mid-J CO and [CI]
easy from the ground…) PDRs, HII regions, shocks, galactic tori, warm dense
molecular/neutral gas
Evolution of GalaxiesEvolution of Galaxies
Near unique niches for studying the epoch from the peak of the star formation per unit volume through to today’s universe z ~ 0 to 1 for [CII] 158 m line – major gas coolant, probes
PDRs, G, intensity, size of starburst z ~ 0 to 1 for [NII] 205 m line – probes low density HII
regions, proxy for Lyman continuum photons, separates [CII] fraction from ionized gas.
z > 2 [OI] 63 m studies – major PDR gas coolant, probes dense PDRs, G, size of starburst
SAFIRE is quite competitive with Herschel (especially if SAFIRE is a grating spectrometer – otherwise a next generation spectrometer can fully exploit this sensitivity niche)
SOFIA-SAFIRE FPI or Grating High z SOFIA-SAFIRE FPI or Grating High z LinesLines
SOFIA/SAFIRE is uniquely positioned for [CII] and [NII] studies in the critical redshift range 0 < z < 1
1.E+10
1.E+11
1.E+12
1.E+13
1.E+14
1.E+15
0 0.5 1 1.5 2 2.5 3
Redshift (z)
Far-IR Luminosity
HLIRGS
ULIRGS
Milky Way
[NII] Grating[NII] SAFIRE
[CII] SAFIRE
[CII] Grating
Thick lines denote unique, or nearly unique sensitivity
5 in 2 hours – ULIRG line to continuum ratios: Adjusted to lower luminosity ratios when L < 1012 L
Blain et al 2002
SOFIA’s Regime
Ground based windows
Torus of AGN: XDRsTorus of AGN: XDRs Dust continuum studies 30 to 60
m Torus very warm (1000 K), and
very dense (~ 107 cm-3) strong neutral line emission (CO, [OI], H2O; Krolik & Lepp,1989)
Typical source @ 100 Mpc: FJ=17-16 ~ 6 10-18 W-m-2
High J CO lines are clear signatures and primary coolants of the confining torus – and are very sensitive to the physical conditions of the torus
SOFIA Advantage: CO SED from J ~ 7-6 to J > 58 (48 m)!
Artist’s conception of the doughnut shaped torus that confines the emission from an active nucleus (Credit ESA).
Galactic Center: Circumnuclear DiskGalactic Center: Circumnuclear Disk Continuum: FORCAST, HAWC
unprecedented spatial resolution Dust mass in the ring Spectrum of density fluctuations
Confinement in strong shear environment– gravity or magnetic fields?
Temperature structure and heating models – young cluster within the disk
Dynamics and excitation with SOFIA Spectrometers Radial motions? Signatures of
dynamical instabilities (infall?) in the velocity field?
Gas T – chemistry and grain composition (T ~ 200 K in ring)?
What is the local "turbulent" velocity dispersion in CND clumps – evidence for MHD waves?
KIWC/KAO Latvakoski et al. 1999
FORCAST 38 m beam
Galactic CenterGalactic Center Magnetic field using HAWC-
polarimeter (not first-light, but possibly not far behind) The 7" beam (@ 60 )
would provide the best measure yet of the GC magnetic field strength using the Chandrasekhar-Fermi method
The magnetic field direction in the warmest clouds (including the CND) would be determined from the orientation of the polarized E-vectors.
Mapping speed will be an issue here!
Near Future PlansNear Future Plans
Gather up and distribute previous White papers to team (Vacca)
Compile and distribute current instrument capabilities, and estimates for second generation capabilities and compare with Herschel capabilities (Stacey – see Tielens and Casey draft…)
Assign key people to investigate science topics (Team)
Report and debate findings on telecons Put together document