Download Galactic Neighborhood and (Chandra-enabled) X-ray Astrophysics Q. Daniel Wang

Galactic Neighborhood and (Chandra-enabled) X-ray Astrophysics
Q. Daniel Wang
(University of Massachusetts)
Frontier Science Galactic Neighborhood Panel
Members:
Leo Blitz, Julianne Dalcanton, Bruce Draine, Rob
Fesen, Karl Gebhardt, Juna Kollmeier, Crystal
Martin, Michael Shull (chair), Jason Tumlinson,
Daniel Wang, Dennis Zaritsky, Steve Zepf
+ Astro2010 Science Liaison: Scott Tremaine
“Galactic Neighborhood” defined as:
Milky Way and Local Group (stars, ISM,
satellites)
Galaxies out to redshifts z ≈ 0.1
(distance 420 Mpc, lookback 1.3 Gyr)
Enables detailed study of:
•  Resolved stellar populations
•  Complex interconnected processes (stars-SMBHsISM-CGM-IGM interactions; large/small scales)
•  Local counterparts of distant objects (DM halos,
SMBHs, dwarfs, feedback/accretion)
Four Science Questions:
•  (Q1) What are the Flows of Matter & Energy in
the Circumgalactic Medium (CGM)?
•  (Q2) What controls the Mass-Energy-Chemical
Cycles within Galaxies?
•  (Q3) What is the Fossil Record of Galaxy
Assembly and Evolution from the First Stars to
the Present?
•  (Q4) What are the Connections between Dark
and Luminous Matter?
Areas of Discovery Potential:
•  Time-Domain Astronomy
•  Astrometry
Unique X-ray observing
capabilities of Chandra
•  Highest spatial resolution
–  Resolving X-ray structure
–  Detecting faint sources
–  Cleanly exercise sources for diffuse X-ray analysis
•  Highest spectral resolution from LETG and
HETG over the 0.2-8 keV range.
–  Allowing for real X-ray spectroscopy, with subarcsecond spatial (albeit mostly 1-D) resolution
•  Stable and low non-X-ray background
–  Particularly important for studying large-scale
diffuse X-ray emission.
Q1, 2, and 4 are closely related to a single question:
How does feedback work in and around galaxies?
Feedback represents the least understood part of
the structure formation and evolution theory: 1) the subgrid physics and 2) the global impact.
Hubble, Chandra, Spitzer
metal transport out to ~1 Mpc
X-raying the fundamental micro
and/or interface astrophysics
NTF G359.54+0.18 in
the Galactic center
Radio: Yusef-Zadeh et al. (1997)
galaxy ESO 137-001 in Abell 3627 X-ray on optical image: M. Sun, et al
•  Particle acceleration
•  Magnetic field
reconnection
•  Charge exchange
•  Plasma cooling and
heating
•  Mass-loading
•  Thermal evaporation/
condensation
A Chandra workshop on
feedback astrophysics?
How does the Feedback Affect the
Global ISM?
•  How does the feedback
affect the ISM and the
star formation (suppress
or induce SF)?
•  How does the feedback
drive outflows (via
radiation, thermal
pressure, and/or cosmicray)?
Townsley et al.
How does the Feedback Affect the Global
CGM or the baryon/dark matter relation?
•  How much mass and energy can
escape into the CGM?
•  How does the feedback regulate
the IGM accretion of galaxies?
Approach 1: X-ray absorption line
tomography:
•  More sight-lines and deeper
observations.
•  Measure the global mass-energymetal content, transport,
thermal/kinematic structures of
diffuse hot plasma in and around
our Galaxy.
How does the Feedback Affect the
Global CGM?
Approach 2: Deep large-scale X-ray mapping:
•  Individual observations have to be deep to remove
enough background sources, which causes the cosmic
variance. •  To check physical properties of hot plasma near outer
boundaries if they are present.
Mkn 231, 0.5 Ms ACIS 0.5-8 keV
Veilleux et al. 2014 NGC 253
(Q4) Dark & Luminous Matter Connection
What can X-ray observations tell us about the
nature of the dark matter (e.g., via particle decay
and annihilation, and self-interaction)?
(Discovery area) Time-Domain Astronomy
Enormous swaths of parameter space of the
transient sky remain to be explored.
Chandra, with its unique high resolution capability
is well positioned for potential major discoveries of
transient events and for variability studies of
relatively faint X-ray sources in crowded fields.