This document provides an overview of astronomical facilities and galaxy research in South Africa. It discusses the South African Astronomical Observatory (SAAO) and its facilities including the Southern African Large Telescope (SALT). It also describes other national facilities such as the Hartebeesthoek Radio Observatory and research involving the High Energy Stereoscopic System. The document outlines several galaxy research projects involving interactions between galaxies, star formation, and galaxy evolution across cosmic time.

1. South African Astronomical
Facilities and Galaxy Research
Petri Vaisanen - SAAO and SALT

2. Outline
● Astronomy in South Africa
● Astronomical Facilities in SA
● Various galaxy research projects
7 Oct 2011 ILOA/ SAAO

3. National Astronomical Facilities
☻H.E.S.S.
South African Astronomical Observatory
(SAAO) ☻HartRAO
Southern African Large Telescope
(SALT)
Hartebesthoek Radio Observatory
(HartRAO)
High Energy Stereoscopic System ☻KAT-7
(H.E.S.S.) ☻SAAO + SALT
Karoo Array Telescope (MeerKAT)
(KAT) X
Square Kilometre Array
(SKA) You are here
7 Oct 2011 ILOA/ SAAO
Summer School 3

4. South African Astronomical Observatory
Mission: to perform research in astronomy; To
provide an international facility in Africa for such
research; to educate and inform the community
Total staff: >120
Scientists: Physics
Astronomy
Mathematics
Engineers/Technicians
Electronics
Mechanical
Optical
Computer
Science Educators
History: dates from 1820
HQ: Cape Town, Western Cape
7 Oct 2011 ILOA/ SAAO
Observing Facilities: Sutherland, Northern Cape
Summer School 4

5. Where is Sutherland
and SALT? Sutherland
Good dark
astronomical site:
Aseasonal with
75% nights
spectroscopic or
better - 50% are
photometric
Median seeing of
0.9 arcsec (DIMM)
SAAO & SALT HQ
~1800 m altitude
7 October 2011 ILOA/ SAAO

6. SAAO Research Facility
Sutherland - Time share:
reflecting telescopes: ~20% international
1.9, 1.0, 0.75, 0.5 m, ~20% SA universities
+ 1.4 m IRSF and several new ~60 % SAAO
small and 1.0-m class robotic
telescopes
7 Oct 2011 ILOA/ SAAO
Summer School 6

7. 7 Oct 2011 ILOA/ SAAO
Summer School 7

8. 7 Oct 2011 ILOA/ SAAO

9. First light and start of Initial science verification
commissioning at end of phase in 2006 - 2007.
2005.
Problems identified….
Engineering team left then.
Off-sky from April 2009 to
August 2010 for a major fix.
Re-commissioning of
telescope and instruments
since then.
Back to science operations
in mid- 2011.

10. SALT: A Fixed Elevation Optical-IR Telescope
(modelled on the Hobby-Eberly Telescope (HET) in Texas)
SALT’s BASIC ATTRIBUTES
• 11-m SEGMENTED PRIMARY MIRROR
– Spherical Figure
– 91 identical hexagonal segments
• TELESCOPE FIXED TILT AT 37o
– Azimuth (left-right) rotation for
pointing only
– Reaches 70% of total southern sky
and 12.5% of sky at any one time
• OBJECTS TRACKED BY “TRACKER”
– Tracker contains “Payload” with
optics & instruments
7 October 2011 ILOA/ SAAO

11. 91 one-metre segments
- with passive and active alignment systems
7 October 2011 ILOA/ SAAO

12. Annulus of visibility
for SALT:
Annulus represents
12.5% of visible sky at
any point of time
Declination range:
+10º to -75º
Observation time
available = time
taken to cross
annulus
7 October 2011 ILOA/ SAAO

13. NGC6864
SALTICAM (built @ SAAO)
• CCD camera: 320 to 900 nm range,
10x10 arcmin field-of-view .
• UBVRI, uv-340, uv-380, Sloan,
Stromgren filters
• Time resolution down to 60 ms (slot
and frame-transfer mode)
• Drift-scanning
Has worked well from the beginning
7 October 2011 ILOA/ SAAO
47 Tuc: Lagoon Nebula

14. RSS: Robert Stobie Spectrograph
(formerly PFIS)
PI: Ken Nordsieck, University of Wisconsin-Madison
• Long slit and multi-object (>100) spectroscopy (320-900 nm,
medium resolution, R to 6,000 @ 1 arcsec) over 8’ diameter FoV, UV
coverage is rare on large telescopes
• Volume Phase Holographic transmission gratings and ‘swinging’
camera enable very flexible Res and wavelength coverage.
• Fabry-Perot imaging spectroscopy using double etalons R = 320-
770 (low res.), R = 1250 – 1650 (medium) & 9000 (high)
• Imaging polarimetric and spectropolarimetric modes
• High Time resolution ~100 ms spectroscopy (charge shuffling, no
dead-time) and fast photometry (rare on large telescopes),
• Upgrade to near-IR beam (J,H ~2012)
7 October 2011 ILOA/ SAAO

15. RSS: Robert Stobie Spectrograph
(formerly PFIS)
PI: Ken Nordsieck, University of Wisconsin-Madison
• Long slit and multi-object (>100) spectroscopy (320-900 nm,
medium resolution, R to 6,000 @ 1 arcsec) over 8’ diameter FoV, UV
coverage is rare on large telescopes
• Volume Phase Holographic transmission gratings and ‘swinging’
camera enable very flexible Res and wavelength coverage.
• Fabry-Perot imaging spectroscopy using double etalons R = 320-
770 (low res.), R = 1250 – 1650 (medium) & 9000 (high)
• Imaging polarimetric and spectropolarimetric modes
• High Time resolution ~100 ms spectroscopy (charge shuffling, no
dead-time) and fast photometry (rare on large telescopes),
• Upgrade to near-IR beam (J,H ~2012)
7 October 2011 ILOA/ SAAO

16. Radio Astronomy
Hartebeesthoek Radio Observatory:
26-m dish at Hartebeesthoek: International VLBI network
(1960s NASA satellite tracking)
SA bidding to host the
Square Kilometre Array (SKA)
– KAT-7 (2010)
– MeerKAT (2015+)
– SKA (2020+)
7 Oct 2011 ILOA/ SAAO
Summer School 16

17. Radio Astronomy
Hartebeesthoek Radio Observatory:
26-m dish at Hartebeesthoek: International VLBI network
(1960s NASA satellite tracking)
SA bidding to host the
Square Kilometre Array (SKA)
– KAT-7 (2010)
– MeerKAT (2015+)
– SKA (2020+)
7 Oct 2011 ILOA/ SAAO
Summer School 17

18. MeerKAT – under construction
Summer School 18

19. Summer School 19

20. 7 Oct 2011 ILOA/ SAAO

21. 7 Oct 2011 ILOA/ SAAO

22. Gamma-Ray Astronomy
Gamma-Ray:
South Africa is a partner in the
High Energy Stereoscopic
System (H.E.S.S.), based
in Namibia
And will participate in
future gamma-ray
observatories, HESS-II
7 Oct 2011 ILOA/ SAAO
Summer School 22

23. H.E.S.S.
Array of 4 telescopes
Multiple telescopes allows
stereoscopic reconstruction
of shower geometry
7 Oct 2011 ILOA/ SAAO
Summer School 23

24. Number of PhD Astronomers
in SA (October 2010)
Institution Number Institution Number
UCT 29 Wits 4
SAAO 25 UJ 3
UWC 8 UFS 2
UNW 7 UNISA 2
HartRAO 7 Rhodes 1
KAT 6 UZ 1
UKZN 6
101 astronomers (66 in Western Cape)
and new posts in UCT, SAAO, UWC,
7 Oct 2011 HartRAO, Wits, UNISA, SAAO
ILOA/ Rhodes …
Summer School 24

25. Galaxy formation and evolution
questions?
 One of the main unsolved topics of modern astronomy
and astrophysics
 Details regarding star formation and feedback from
supernovae, AGN, etc. are complicated
 How and when did the first galaxies form?
 How and why are they changing now?

26. Star formation and dynamics in
interacting IR galaxies
Petri Väisänen (SAAO / SALT)
Alexei Kniazev, Abiy Tekola, Zara Randriamanakoto, Rajin Ramphul
Seppo Mattila, Jari Kotilainen, Juha Reunanen, Erkki Kankare (Turku),
18 March 2011
Stuart Ryder (AAO), Miguel Perez-Torres (Granada),
Granada
Angela Adamo (Heidelberg), Goran Ostlin (Stockholm), et al.

27. Interacting and merging galaxies
● An evolutionary sequence – how is this happening exactly ?
gas spirals → starburst / ULIRG → obscured AGN → QSO →
elliptical galaxy
7 Oct 2011 ILOA/ SAAO

28. e.g. the Antennea galaxies

29. Star formation density vs. redshift
Normal galaxies
LIRGS
ULIRGs

30. Many questions remain
●
Interplay between AGN and star
formation, what exactly triggers
what? Are the evolutionary
transitions causal or coincidental?
●
How do the galactic outflows
(feedback) affect the evolution?
●
WHY are some galaxies
LIRGs?
●
And WHY are they not
ULIRGs?
●
How are the processes different
at high redshifts?
7 Oct 2011 ILOA/ SAAO

31. AO data of LIRGs
●
VLT/NACO and Gemini/Altair
NIR adaptive optics programs
– High spatial resolution (~0.1”) K-band
images of “LIRGs”
– 32+8 targets, mostly at 60-120 Mpc,
strong AGN excluded, wide range of
interaction stages
– Data match very well optical HST/ACS
LIRG imaging archival data
– Complemented by archival Spitzer
data and ground based spectroscopy
with SALT
77Oct 2011
October 2011
ILOA/ SAAO

32. SAAO 1.9-m spectroscopy and NOT
nb-imaging of starburst galaxies
 Future: metallicity gradients in interactions with SALT/RSS
H_alpha
R-band

33. ESO 221-IG008
7 Oct 2011 ILOA/ SAAO

34. IRAS 19115-2124
18 March 2011 Granada

35. IRAS 19115-2124
18 March 2011 Granada

36. IRAS 19115-2124 –
“The Bird”
18 March 2011 Granada

37. RSS data
What's up
with the
Head ??
SALT spectroscopy planned for whole sample
Cool gas outflows of 100-400 km/s SAAO
77Oct 2011
October 2011 Granada
ILOA/

38. Bird - New data with SINFONI and VISIR
●
cont. Pa α
~80% of current
SF is in the smallest
Component.
Bird is a LIRG
because of its
“Head”
Vaisanen, Reunanen,
Kotilainen (in prep.)
77Oct 2011
October 2011
ILOA/ SAAO

39. Super star clusters (SSC)
●
Determining spatial
distributions of SSCs and
determining LFs
●
Combining HST data to
model ages and masses.
Randriamanakoto et al. (in prep)
77Oct 2011
October 2011
ILOA/ SAAO

40. Local star-bursting dwarfs
(led by Alexei Kniazev, SALT/SAAO)
7 Oct 2011 ILOA/ SAAO

41. Motivation
Young galaxies at high redshifts are too faint to study them in
detail. But their local cousins can provide a valuable information
on the processes of galaxy formation and early evolution.
7 Oct 2011 ILOA/ SAAO

42. HII in IC4662
Distance of 2.5 Mpc.
M(B) = -15.5 mag.
Isolated galaxy.
Previously studied by
Hidalgo-Games et al. (2001)
with 3.6m ESO telescope:
ΔV(A-D) = 200 km/s
O/H = 0.5 dex
We would like to prove
difference in O/H and B
velocities between D and
main body: A1, A2, B.
Measuring metallicities
7 Oct 2011 ILOA/ SAAO Kniazev et al. (2010, in ~ 190”x180
Image size preparaion)

43. Spectra
7 Oct 2011 ILOA/ SAAO

44. HII in IC4662 (4)
Region SALT (O/H) 3.6m (O/H) E(B-V)
A1 8.13±0.02 8.17±0.06 0.27
A2 8.09±0.02 8.17±0.12 0.27
D 7.92±0.08 7.70±0.10 0.27
B 8.05±0.05 ... 0.24
Evidence for chemical inhomogeneity in a dIrr galaxy?
(Kniyazev et al. 2005 for Sextans B)
or
gradient of abundances?

45. University of Witwatersrand
(Prof. David Block, Dr. Robert Groess, et al.)
Classifying galaxies
Modelling galaxies
Especially IR galaxies
7 Oct 2011 ILOA/ SAAO

46. 7 Oct 2011 ILOA/ SAAO

47. 7 Oct 2011 ILOA/ SAAO

48. Lenticular galaxy formation:
An Observers Prospective
Sudhanshu Barway
South African Astronomical Observatory (SAAO)
Ajit K. Kembhavi (IUCAA)
Yogesh Wadadekar (NCRA)
Y. Divakara Mayya (INAOE)

49. Lenticular Galaxies
Lenticular galaxies come in a variety of shapes –
Nuclear structures
Central 10″ x10″ region of galaxies from HST-WFPC2, I band images

50. Lenticular Galaxies
How do galaxies form/evolve in different environments?
Possible Physical Processes
o Mergers
o Harassment (high speed encounters)
o Strangulation (interactions remove gas, halts star formation)
o Ram pressure stripping (cluster medium removes gas, halts SF)
o Non-gravitational processes (AGN, SNe)
7 Oct 2011 ILOA/ SAAO

51. Dr. David Gilbank (SAAO)
7 Oct 2011 ILOA/ SAAO

52. 7 Oct 2011 ILOA/ SAAO

53. 7 Oct 2011 ILOA/ SAAO

54. + many post-docs and students
[Slides courtesy of Catherine Cress (UWC)]

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57. 7 Oct 2011 ILOA/ SAAO

58. Summary:
South Africa has a 10-m
world-class telescope
available, fitted with highly
versatile instruments.
World class facilities
coming up in radio.
It is a very exciting time to
be working with
astrophysical research in
Africa!
7 Oct 2011 ILOA/ SAAO