Transcript The Astronomy Department (UCT) Renée C. Kraan-Korteweg, Head of Astronomy • Academic Staff and Graduate Students • Teaching programmes • Overview Research • History of.

The Astronomy Department (UCT)
Renée C. Kraan-Korteweg, Head of Astronomy
• Academic Staff and Graduate Students
• Teaching programmes
• Overview Research
• History of Astronomy
• Variable stars
• Galactic structure and distance scale
• Extragalactic large scale structure
• Zone of Avoidance
• Visualisation of a large-scale structure
• Galaxy evolution and transformation
• Near Field Cosmology
Members of the Astronomy Department (UCT)
Permanent Academic & support staff;
Emeritus and Honorary professors
Since Jan 2005
From Jun 2007
Permanent since Jan 2005; 2000-2004 Senior Research Fellow
Since Jan 2006
Honorary Professors associated with the Astronomy Department
SAAO; Math Dept. (UCT);
NASSP
SARChI:  Research Chair in Extragalactic Radio Astronomy
At the Astronomy Department (UCT)
UCT
ASTRONOMY DEPARTMENT
SARCI RESEARCH CHAIR
KAT/SKA
SAAO/SALT
Applied
Mathematics
Cosmology
Group
Electrical
Engineering
Radar & Remote
Sensing Group
Physics
Theoretical
Astrophysics
Group
Capacity Building
UWC
EDUCATION
RESEARCH
• Astrophysics
U/Grad Programme
SALT,KAT,SKA,HESS
• NASSP
Brings a lot of funding to the group in the form of equipment, operating costs and
foremost bursaries for graduate students
Graduate Students of the Astronomy Department (UCT)
6 PhD students:
8 MSc students (all part of NASSP):
Plus 3 part-time external
registered students:
- Claire Blackman (PhD)
- Pierre Vermaak (PhD)
- Denis Dale (MSc)
1 PhD and 3 MSc students (all NASSP) with primary supervisor of SAAO
Postdoc positions at the Astronomy Department (UCT)
-Through the SARChI Chair and independently from the SKA bursary office
(4 of the new graduate students are supported though SKA bursaries)
 Advertisement of 2 postdoctoral positions
(application deadline 1 May 2007)
Details on our website:
-http://mensa.ast.uct.ac.za
- AAS March Job Register 28345
“We are looking for enthusiastic candidates interested in joining the newly formed
radio group in extragalactic astronomy to initiate research projects optimized for the
unique properties of MeerKAT. Candidates will also have access to the 30% SouthAfrican share on SALT and other optical/NIR telescopes at SAAO.
The successful applicants will work with Prof. Erwin de Blok (new SARChI Chair in
Radio Astronomy as of June 2007) and Prof. Renée Kraan-Korteweg on
extragalactic HI-surveys, galaxy evolution and aspects of radio interferometry”.
Teaching by the Astronomy Department (UCT)
- A 3-year PhD programme (AST 6000W)
- Honours and Masters programme – mostly within NASSP
All members teach in NASSP graduate programme
(though a 2 year pure research masters is still possible AST5000W)
And T. Medupe and R. Kraan-Korteweg form part of local NASSP Exco
NASSP Honours:
-Prof. Tony Fairall
-Dr. Patrick Woudt
- Introduction to Astronomy
(as part of NASSP Summerschool)
- Galaxies
- General Astrophysics I
NASSP Masters:
-Dr. Thebe Medupe
-Prof. Renee Kraan-Korteweg
-Prof. Brian Warner
- Stellar Structure
- Extragalactic Astronomy
- Cataclysmic Variables
Undergraduate Teaching
The Astronomy department always offered
- AST1001F : An Introduction to Astronomy (open to all students – generally ~70 students)
- AST2002S: An Introduction to Modern Astrophysics (between 20 – 30 students)
In 2006: Introduction of Astrophysics specialisation
within MPSS (Mathematical, Physical and Statistical Sciences Programmes)
Undergraduate Astrophysics Specialisation (UCT)
With: - AST3002F: Stellar Astrophysics
-AST3003S: Galactic and Extragalactic Astronomy; Cosmology
Introduced in 2006: Extramural e-learning course
”The cosmos - an introduction to the universe”
- An innovative ten-week course for those interested in basic astronomy will be offered by the
Centre for Open Learning in April.
- Led by Profs Tony Fairall and Brian Warner
- offers a special opportunity to learn at your own pace and time.
 Students can then access course notes, reading and any practical work required via the
course e-learning forum from their home computer.
(Eight modules are to be completed during the 10-week period of the course. Each week, a
new module can be downloaded and studied).
- It draws on some of the material from the UCT first-year semester course in astronomy
- It is not a UCT credit-bearing course
- but a certificate of completion from UCT's Centre for Open Learning.
- Charge ZAR 1800.– (a lot of business people, teachers, retired professors)
Research at the Astronomy Department (UCT)
Professor Renée C. Kraan-Korteweg (HOD)
Large-scale structures and streaming motions in the nearby Universe, the zone of avoidance, the Great
Attractor; systematic HI-surveys; evolution and transformation of galaxies; the dark matter content of nearby
dwarf and LSB galaxies; search for intermediate black holes
Professor Anthony P. Fairall
Large-scale structures and streaming motions in the nearby Universe; the zone of avoidance; active
galaxies; visualisation and analysis of large-scale structure
Senior Lecturer Dr. Patrick A. Woudt
Large-scale structures and streaming motions in the nearby Universe, the zone of avoidance, the Great
Attractor; evolution and transformation of galaxies; the dark matter content in nearby dwarf galaxies;
cataclysmic variable stars, ultra-compact binaries
Senior Lecturer Dr. R.T. Medupe (UCT/SAAO)
Observational and computational modeling of variable stars; history of astronomy, Timbuktu manuscripts
Honorary Professor Michael W. Feast
Stellar evolution; galactic structure; long period variable stars; distance scales
Emeritus Distinguished Professor Brian Warner
Cataclysmic variable stars; white dwarf stars; history of astronomy
Research Chair in Extragalactic Radio Astronomy
Low surface brightness galaxies; Dark Matter; interstellar medium; evolution of disk galaxies, HI sky
surveys, Radio Astronomy
Thebe Medupe’s research topics
•
Search for Astronomy in ancient
manuscripts from West Africa (Timbuktu).
We want to use these to attract African
youth into Science
•
Numerical computations of seismic
waves in stars. These (when compared
with observations) allows us to infer
internal structure of stars.
•
 Diverge into:
Cosmology and Dark Matter Studies of
galaxies
High-speed photometry and spectroscopy of cataclysmic variables
Brian Warner and Patrick Woudt (Univ. of Cape Town)
• Dwarf nova oscillations (DNOs) in cataclysmic variables (CVs): probing the physics
of accretion onto white dwarfs.
Magnetically-channeled
DNOs in VW Hyi.
U-band highaccretion onto white dwarf.
• Ratio of quasi-periodic oscillation
(QPO) to DNO in CVs is
similar to ratio of QPOs in
low-mass X-ray binaries.
Implications for the nature of
accretion onto a wide variety
of compact accretors (white
dwarfs, neutron stars and
black holes).
• Specific focus on: ultracompact
binaries (AM CVn stars) and
non-radially pulsating
accreting white dwarfs in CVs
speed photometry
with SALTICAM
(80 milliseconds).
Part of lightcurve
obtained with SALT.
2 QPO-diagram for
low-mass X-ray
binaries (blue dots)
and CVs (red dots).
CV observations
obtained with the
UCT CCD on the
SAAO 1-m and 1.9-m
telescopes.
(Warner, Woudt &
Pretorius 2003).
Distance Scale to (and) Nearby Galaxies
Michael Feast, Patricia Whitelock, John Menzies
Some Recent Highlights
Examples of reddening-free period-luminosity relations for classical cepheids. The Cepheid parallaxes were
derived from a combination of HST and ground-based measures (AJ in press).
These results are currently being combined with newly revised Hipparcos parallaxes to further improve the
relations and apply them to a redetermination of the Hubble constant (w. F van Leeuwen; Cambridge).
Extensive work has been carried out (IRSF)
on Local Group galaxies (like Leo I -picture)
to study their composition and evolution
using AGB variable stars (John Menzies,
PAW, MWF).
Examples of Period-Luminosity relations for type IICepheids in globular clusters obtained in a Tokyo-SA
collaboration (IRSF observations, Matsunaga et al.).
Work is in progress to calibrate these relations using
revised Hipparcos parallaxes and so improve
estimates of the distances and ages of globular
clusters.
(van Leeuwen (Cambridge), PAW + MWF)
Extragalactic large-scale structures – and
The ZOA: An obstacle to cosmological studies
The distribution of cataloged galaxies with D ≥ 1.3´
Extragalactic large-scale structures – and
The ZOA: An obstacle to cosmological studies
•Continuity and size of superclusters/voids crossing the Gal. Plane
Local Supercluster (SGP), Great Attractor (GA), Perseus-Pisces Scl
•Dipole determinations
Vpec(LG) ↔ CMB dipole; requires knowledge of whole-sky mass distribution
•Dynamics of the Local Group
possible existence of another Andromeda-like galaxy in the ZOA
•Cosmic flow fields
(.g. in the GA region, does the galaxy distribution follow the mass distribution?
How to Peak through the Milky Way?
• Systematic deep optical
searches with spectroscopic
follow-ups
 Great Attractor
•Future: Salt, NIR, MIR
• Systematic HI-surveys
The only way to probe into
the most opaqe part of the MW
(Dw1; GA)
Future: Meerkat
•NIR (and now MIR) Surveys
2MASS  IRSF  Spitzer
(most massive spiral galaxy
uncovered)
Dynamics of galaxy clusters in the Great Attractor
Patrick Woudt, Renée Kraan-Korteweg, Tony Fairall (Univ. of Cape Town)
• Norma cluster at the heart of the Great Attractor is the nearest rich cluster
in the Universe (closer than the Coma / Perseus clusters).
• Use multi-wavelength (BVRJHKs) photometry of elliptical galaxies in the
Norma cluster to determine the distance (and motion relative to the
Great Attractor) of the Norma cluster (via the Fundamental Plane).
• Star-crowding and extinction require a careful photometric analysis.
• Probing internal dynamics of the Great Attractor (massive supercluster).
WKK 6269 (JHKs)
WKK 6269 is
the central cD
galaxy in the
nearby rich
Norma cluster
at the core of
the Great
Attractor. Image
taken with IRSF
at Sutherland.
WKK 6269 (Ks)
WKK 6269 (no stars)
WKK 6269 (foreground)
Evolution and transformation of galaxies in superclusters at
intermediate redshifts (z ~ 0.15 – 0.60)
Patrick Woudt, Renée Kraan-Korteweg, Tony Fairall (Univ. of Cape Town)
Using SALT (multi-object spectroscopy and deep imaging) of selected superclusters
at z ~ 0.15 → 0.6, we aim to identify processes of galaxy transformation within
the extended supercluster environment.
Transformation processes, transition stages and time scales as a function of
supercluster properties (richness, mass, relaxation of individual clusters), location
within the supercluster (as a function of virial radii from the clusters; outskirts?) and
(super)cluster dynamics.
Benefits of SALT:
wide field of view, blue sensitivity,
multi-object spectroscopy.
Coverage: L* + 6 mag (dwarf population)
← Abell 1445, a central cluster in a supercluster at z ~ 0.17 (SDSS gri colour image)
The recently completed 6dF Galaxy Survey
Example: cross-section of large-scale structures and voids (the dots are galaxies).
Some regions show a high density of galaxies with small voids;
intervening regions have low density and large voids.
V19
V22
V21
V46
V180
PI S CI S
A US
V34
V36
V35
V32
V212
S
N I
L O
A
G I
U M - C
V45
M
A
V20
ZOA
J O
SGX = -3000
R
O
MICROSCOPIUM
VOID
V33
V218
V216
V215
V217
V193
V213 (GREAT RIFT)
V221
V214
V223
O
R
V209
V220
O
V208
V207
V210
H
V192
SCU
LPT
OR
(b)
V223
V?
V219
V222
The width of this slide is
about a billion light years
6dF SOUTHERN GALACTIC HEMISPHERE
100 M pc
Back to the ZOA: Galaxies known within b = ±5° before MB survey
Galaxies (1036) discovered with the Parkes MB HI Survey
Follow-up with MeerKat: deeper and solve for controversy
GA vs Shapley concentration
Mapping the Norma Great Wall footprint
in the NIR (IRSF at SAAO) and MIR (Spitzer)
Footprint = 55 □º
(a) Spitzer IRAC:
36s (Glimpse: 2s) per
pointing
→ 175 hrs
Not successful 2006 
But other ZOA other
area!!!
(b) IRSF : 4050 fields
→ ~700 hrs
New Mosaic: Two highly obscured (AB = 19 mag) spiral
galaxies
At
l = 317.04, b = -0.50
l = 316,87, b = -0.60
AB ~10 mag
Any connection
with the GA?
Superposition of HI contours (ATCA April 2006)
on Glimpse image:
Jarrett et al. 2007
→ the 2 Glimpse galaxies are confirmed
→ they lie at the distance of the GA overdensity
→ they have typical HI masses for normal star-forming Sb or Sc
MHI = 2.2 109 Msun and 1.1 109Msun respectively (H0=72)
HIZOA J0836-43: the most HI-massive galaxy known?
Donley et al. (2006)
Image: AAT K-band.
Contours: ATCA HI.
• MHI=7x1010 Msun (more massive than Malin-1)
• Mtot=1.1x1012 Msun
• AB=12 mag (b=-1.6o)
• Diameter 100 kpc (~10 revolutions in 14 Gyr)
Predictions galaxy formation models
•
Hierarchical galaxy formation
– The most massive present-day galaxies were formed at z  1
(e.g. Mo et al. 1998, van den Bosch 1998)
– The number of massive galaxies should decline exponentially
above a characteristic value, M*. From the HIPASS BGC HI
mass function, M* = 6x109 M☼
Zwaan et al. 2003
Dark Matter in Galaxies
Erwin de Blok (soon UCT)
• Dark matter is the most important mass ingredient of
our universe
• But we do not understand it
• Cosmological computer simulations make excellent
predictions of the large scales (clusters of galaxies)
Springel et al 2005
Small Scale Dark Matter
• The simulations give incorrect predictions for the distribution of DM
at galaxy scales: cosmology’s Achilles heel
• High-resolution observations of the dynamics of gas and stars in
nearby galaxies can possibly measure the DM distribution
HI Nearby Galaxy Survey
• Largest and highest resolution set of
galaxy radio observations ever
• Combined with GALEX and Spitzer: full
view of baryons and proper physics
• Best chance of measuring DM in galaxies
• Constrain Cosmology