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

Honorary Professors associated with the Astronomy Department

SAAO; Math Dept. (UCT); NASSP

Since Jan 2005

From Jun 2007

Since Jan 2006

Permanent since Jan 2005; 2000-2004 Senior Research Fellow

ASTRONOMY DEPARTMENTSARCI RESEARCH CHAIR

Applied MathematicsCosmology

Group

Electrical Engineering

Radar & Remote Sensing Group

PhysicsTheoretical Astrophysics

Group

UCT

SAAO/SALT KAT/SKA

EDUCATION RESEARCH

• Astrophysics U/Grad Programme SALT,KAT,SKA,HESS

• NASSP

Capacity Building

ASTRONOMY DEPARTMENTSARCI RESEARCH CHAIR

Applied MathematicsCosmology

Group

Electrical Engineering

Radar & Remote Sensing Group

PhysicsTheoretical Astrophysics

Group

UCT

ASTRONOMY DEPARTMENTSARCI RESEARCH CHAIR

Applied MathematicsCosmology

Group

Electrical Engineering

Radar & Remote Sensing Group

PhysicsTheoretical Astrophysics

Group

UCT

SAAO/SALTSAAO/SALT KAT/SKAKAT/SKA

EDUCATION RESEARCH

• Astrophysics U/Grad Programme SALT,KAT,SKA,HESS

• NASSP

Capacity Building

EDUCATION RESEARCH

• Astrophysics U/Grad Programme SALT,KAT,SKA,HESS

• NASSP

Capacity Building

SARChI: Research Chair in Extragalactic Radio AstronomyAt the Astronomy Department (UCT)

Brings a lot of funding to the group in the form of equipment, operating costs and foremost bursaries for graduate students

UWC

Graduate Students of the Astronomy Department (UCT)

6 PhD students:

1 PhD and 3 MSc students (all NASSP) with primary supervisor of SAAO

8 MSc students (all part of NASSP):

Plus 3 part-time external registered students:

- Claire Blackman (PhD)

- Pierre Vermaak (PhD)

- Denis Dale (MSc)

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% South-African 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 NASSPAll 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 - Introduction to Astronomy

(as part of NASSP Summerschool)- Galaxies

-Dr. Patrick Woudt - General Astrophysics I

NASSP Masters:-Dr. Thebe Medupe - Stellar Structure-Prof. Renee Kraan-Korteweg - Extragalactic Astronomy-Prof. Brian Warner - Cataclysmic Variables

Undergraduate TeachingThe 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. FairallLarge-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. WoudtLarge-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. FeastStellar evolution; galactic structure; long period variable stars; distance scales

Emeritus Distinguished Professor Brian WarnerCataclysmic variable stars; white dwarf stars; history of astronomy

Research Chair in Extragalactic Radio AstronomyLow 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 physicsof accretion onto white dwarfs.Magnetically-channeledaccretion onto white dwarf.

• Ratio of quasi-periodic oscillation(QPO) to DNO in CVs is similar to ratio of QPOs inlow-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) andnon-radially pulsatingaccreting white dwarfs in CVs

DNOs in VW Hyi.U-band high-speed photometrywith SALTICAM(80 milliseconds). Part of lightcurveobtained with SALT.

2 QPO-diagram forlow-mass X-ray binaries (blue dots)and CVs (red dots).CV observations obtained with theUCT CCD on the SAAO 1-m and 1.9-mtelescopes.(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).

Examples of Period-Luminosity relations for type II- Cepheids 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)

Extensive work has been carried out (IRSF) on Local Group galaxies (like Leo I -picture) to study their composition and evolutionusing AGB variable stars (John Menzies, PAW, MWF).

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?

Extragalactic large-scale structures – and

The ZOA: An obstacle to cosmological studies

How to Peak through the Milky Way?

• Systematic deep optical searches with spectroscopic follow-ups Great Attractor•Future: Salt, NIR, MIR

• Systematic HI-surveysThe 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)

WKK 6269 (JHKs) WKK 6269 (Ks) WKK 6269 (no stars) WKK 6269 (foreground)

• 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 isthe central cDgalaxy in thenearby richNorma clusterat the core ofthe GreatAttractor. Imagetaken with IRSFat Sutherland.

Evolution and transformation of galaxies in superclusters atintermediate redshifts (z ~ 0.15 – 0.60)

Patrick Woudt, Renée Kraan-Korteweg, Tony Fairall (Univ. of Cape Town)

← Abell 1445, a central cluster in a supercluster at z ~ 0.17 (SDSS gri colour image)

Using SALT (multi-object spectroscopy and deep imaging) of selected superclustersat z ~ 0.15 → 0.6, we aim to identify processes of galaxy transformation withinthe extended supercluster environment.

Transformation processes, transition stages and time scales as a function ofsupercluster 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)

SGX = -3000 ZOAO

MICROSCOPIUMVOID

V34

V33V32

V35

V46

V19

V36

V20

V21V22V45

V180

V192

6dF SOUTHERN GALACTIC HEMISPHERE

V207V208

V209V210

V212

V213 (GREAT RIFT)V214

V215

V216

V217

V218

V219

V220

V?

V193V221

V222

V223

V223

H

O

R O

L

O

G

I U

M

- C

A

N

I

SM

A

J

O

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P I S C I SA U S

100 M pc

SCU

LPTO

R (b

)

The recently completed 6dF Galaxy SurveyExample: 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.

The width of this slide is about a billion light years

Back to the ZOA: Galaxies known within b = ±5° before MB survey

Galaxies (1036) discovered with the Parkes MB HI SurveyFollow-up with MeerKat: deeper and solve for controversy

GA vs Shapley concentration

Mapping the Norma Great Wall footprintin 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 connectionwith the GA?

Superposition of HI contours (ATCA April 2006)on Glimpse image:

→ 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)

Jarrett et al. 2007

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

Springel et al 2005

Dark Matter in GalaxiesErwin 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)

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