Transcript SALT Science – UW Madison

SALT Science – UW Madison
Properties of Quasar Host Galaxies
Greg Mosby, Marsha Wolf, Christy Tremonti, and Eric Hooper
The goal of this work is to understand connections between galaxies and the supermassive black holes at their centers, in
the context of galaxy formation and evolution. We study this through the properties of luminous quasar host galaxies,
objects in which the galaxy is actively feeding its black hole. This proposal focuses on a carefully selected sample of SDSS
quasars, chosen over well-defined ranges of black hole mass, redshift and Eddington ratio in order to draw robust
conclusions about these objects.
SSPMODEL
Above: Left: A schematic showing the observation setup and real data using SALT’s RSS. Right: An ideal pair of spectra that
would be used as input to a stellar population modeling code developed by Mosby to determine host galaxy properties.
Metallicities of GRB Host Galaxies
Brian Morsony and John Chisholm
University of Wisconsin-Madison
Color composite image of the host
galaxy of GRB060505, with GRB site
shown (Thöne 2008)
SALT spectra of GRB060505 taken on
5/11/13 with 1.14” seeing
Accurately measuring mass outflow rates in starburst galaxies.
Christy Tremonti,
Corey&Wood
2013-1-UW-008
- Wood
Tremonti
Hubble Tarantula Treasury
Project (HTTP)
Mapping the Tarantula region
with HST imaging
PI Elena Sabbi (STScI)
SALT RSS spectra map
relationships between
stars & gas, and yields insights
into 3-D structures (NE region
with strong line splitting &
filaments shown above).
Multiple slit positions to
sample range of conditions.
HST 30 Dor; Sabbi+ 2013, AJ, submitted
30 Doradus: Stellar Feedback:
Nebular Motions & Ionization
Jay Gallagher---Wisconsin
Long slit RSS
spectra
sample gas
kinematics &
line ratios for
comparison
with HTTP
HST study.
Line splitting illustrates
3-D shell structure;
strong [SII] signature of
possible shocks.
Hα
[NII]
HeI
[SII]
Time-Series Spectra of Accretion
Flows in Pre-MS Binaries
R. Mathieu & B. Tofflemire (UW-Madison)
Initial SALT results – Hα
Sept 2011
ϕ = 0.00
June 2012
ϕ ~0.21
High-resolution, time-series spectra will
help constrain simulations of DQ Tau
stars (see below) providing evidence for
time-variable accretion flows onto PMS
binaries from circumbinary material.
Accretion Flows
July 2012
Circumbinary
Disk
ϕ ~0.04
Å
SALT is inherently ideal for time sensitive
observing campaigns. The nightly frequency
over months required for our science goals
is within SALT’s capabilities but has yet to
be achieved. Currently receiving high
cadence observations!
Circumstellar
Disks
Günther & Kley 2002, A&A 387, 550
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Optical companion:
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V=15.8
Strange spectrum
SALT program:
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Flux (arbit rary)
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M
g
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Like the “missing link” system PSR J1023
(Archibald et al. 2009) that went from
MSP ⬌X-ray binary
H
Radio timing shows weird variations:
lots of gas floating around the system
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Pulsar
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Eclipsing millisecond pulsar discovered
by Parkes (binary period=15h)
C
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PSR J1723
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RSS spectra to measure orbit
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Crawford et al. (2013, ApJ,
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Wavelengt h ( ˚A)
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In this program
(Orio et al.) we
monitor recent
novae, supersoft
X-ray sources
and UV
transients to
study the
accretion process
in close binaries
through the
emission lines
diagnostics.
These line profiles were observed for the recurrent nova T Pyx a year and a half after the
outburst. Nebular [O III] lines at 5007 Å were still very strong and confirmed a bipolar mass
ejection. There seem to be two distincts region of emission, both asymmetric. The He II
emission line at 4686 Å, much less intense, has a double peak profile with the blue (receding
part) less strong than the red like the [O III], but seems to be emitted in a different region.
Megaflares on Tiny Stars
Change in flux at 3500Å
“big” flare
“small” flare
M-dwarf star (YZ CMi);
major flare caught in
Jan 2012. Star 100x
brighter in U-band.
SALT spectra taken at
vertical grey lines.
• Major source of variability for time-domain
astronomy surveys. Especially LSST.
• Large impact on habitability of low-mass stars.
(obs Jan 2012, spectra: Brown et al. SALT/RSS; photometry: Kowalski et al. WHT/La Palma)
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Spectral Movie of Megaflare
Peak flare
emission
Counts/second
100
pre-flare
spectrum
10
1
3000Å
3500Å
Wavelength
M-dwarf star, 15 sec cadence,
R~1000, 70x faster than VLT!
4500Å
5500Å
http://www.astro.wisc.edu/~bpbrown/Movies/
(Brown et al.; obs Jan 2012, SALT/RSS)
Hydrogen
(and other)
emission
lines at peak
Megaflares on tiny stars
Signature of hot
Black body?
Comparable energy release to large (X-class) solar flare.
Whole star brightens by ~100x.
Program has continued through 2013, strong undergrad involvement.