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The Astronomy Department (UCT)

The Astronomy Department (UCT). Ren ée 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

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The Astronomy Department (UCT)

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  1. 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

  2. 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

  3. SARChI:  Research Chair in Extragalactic Radio Astronomy At the Astronomy Department (UCT) UWC Brings a lot of funding to the group in the form of equipment, operating costs and foremost bursaries for graduate students

  4. 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

  5. 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”.

  6. 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 - 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 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)

  7. Undergraduate Astrophysics Specialisation (UCT) With: - AST3002F: Stellar Astrophysics -AST3003S: Galactic and Extragalactic Astronomy; Cosmology

  8. 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)

  9. 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

  10. 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

  11. 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 • accretion 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 DNOs in VW Hyi. U-band high- 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).

  12. 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).

  13. 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 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)

  14. Extragalactic large-scale structures – and The ZOA: An obstacle to cosmological studies The distribution of cataloged galaxies with D ≥ 1.3´

  15. 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?

  16. 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)

  17. 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 (Ks) WKK 6269 (no stars) WKK 6269 (foreground) 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.

  18. 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)

  19. 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. The width of this slide is about a billion light years

  20. 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

  21. 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

  22. 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?

  23. 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)

  24. 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)

  25. 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

  26. 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) Springel et al 2005

  27. 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

  28. 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

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