News from DARKSTAR
1. 08. 2010 Chris Flynn on leave
Chris Flynn will spend a year on leave at the University of Sydney from August 2010.
He will be working on a search for Solar Twins with PhD student Juliet Datson and
the disruptive effects of satellite mergers with host galaxies on globular
cluster populations with PhD student Sarah Bird.
1. 12. 2009 Book published
Leena Tähtinen, Chris Flynn and Esko
Valtaoja's new book,
"Universumi tietokoneessa" or "The
Universe in a computer" has just been published by URSA. The book
discusses how much modern astronomers use the tool of
'simulations' in addition to traditional tools of theory and
observation, to understand the formation and development of the
Universe. Leena Tähtinen passed away on 15.11.2009, shortly
before the book was published. Proceeds from the book will be
donated to a memorial fund in her name at the University of
Turku.
6. 3. 2009 New student
DARKSTAR has a new PhD student, Juliet Datson,
who comes to us from MPIA in Heidelberg. She will be working on solar twins and the star
formation history of the Milky Way. Juliet will spend a year at the NOT telescope starting
in April 2009.
1. 11. 2008 Book published
Leena Tähtinen
and Chris Flynn's book,
"Universumin pimeä puoli" or "The
Dark Side of the Universe" has just been published by URSA. The
book discusses the discovery of dark matter and dark energy, and
how they lead us to believe that 95 percent of the Universe is
still unseen.
19. 9. 2008 DARKSTAR goes to
Tampere
Chris Flynn was invited
speaker at Tampere Cafe Scientifique, where he spoke on "Dark
matter and dark energy -- or What the Universe is made
of".
13. 9. 2008 Sarah Bird obtains
funding
Newly arrived PhD student Sarah
Bird has been awarded a grant from CIMO,
Finland's Centre for International Mobility. Sarah Bird is
studying the kinematics and chemistry of globular cluster
systems. Congratulations, Sarah!
11. 9. 2008 Luca Casagrande
leaves DARKSTAR
Luca Casagrande, who has just
completed his PhD on low mass stars and their helium content,
departs us to take up a postdoctoral position with Martin Asplund
at the Max Planck Institute for Astrophysics in Garching,
Germany. We wish him all the best!
31. 8. 2008 Arrivals and
departures
Erik Zackrisson has left us
to take up a position and the University of Stockholm, where we
wish him well. Sarah Bird has arrived at DARKSTAR to do
her PhD, and will be working with Chris Flynn and Mauri
Valtonen. Welcome Sarah!
30. 5. 2008 Luca
Casagrande defends his PhD
Luca Casagrande, who has been working on Helium
in low mass stars, as well as their fundamental
properties, successfully defended his thesis in the
Astronomy and Physics Department of the University of
Turku on Saturday 22/05/08. Luca's supervisors were
Tuorla Observatory researchers Chris Flynn and Laura
Portinari and his opponent was Professor Bengt
Gustafsson from Uppsala University. Luca has been
offered a postdoctoral position in Garching with
Professor Martin Asplund. Congratulations Luca!
5.5-10.5. 2008 Rainer
Klement visits DARKSTAR
Rainer Klement (Astronomisches
Rechen-Institut, Heidelberg ) revisited DARKSTAR,
working with Chris Flynn on streams of stars in the
Galactic halo, and discussing strange goings-on
in the Galactic bar region with Esko Gardner.
30.3-6.4. 2008 Burkhard
Fuchs visits DARKSTAR
Prof Burkhard Fuchs (Astronomisches
Rechen-Institut, Heidelberg ) was again a very welcome
visitor to DARKSTAR. He worked with Chris Flynn and
Laura Portinari on a new method of reconstructing the
star formation history of the Galaxy's disk from low
mass stars, and gave us a great talk on the OB star
clusters responsible for creating the "Local Bubble" in
the Interstellar Medium.
12. 2. 2008 Luca
Casagrande nearing completion of his PhD
Luca Casagrande, who has been
working on Helium in low mass stars, as well as the
fundamental properties of low mass stars at DARKSTAR,
has submitted the last paper for his PhD thesis, and
will be defending his work in March or April
2008. Luca's thesis work has revealed unexpected
deficiencies in stellar models for low mass stars, the
cause of which is presently unclear. His work has led
to a homogeneous temperature scale for stars from G to M
types, as well as a rough metallicity scale for the M
type stars from optical to near-IR
photometry.
22-27. 10. 2007 Rainer
Klement visits DARKSTAR
Rainer Klement (Max-Planck Institute, Heidelberg )
spent one week at DARKSTAR, working with Chris Flynn on
methods to reconstruct the local mass distribution in
the Milky Way from large new kinematic surveys.
3. 10. 2007 Esko Gardner
visits York University
Esko Gardner is spending two months working with
Prof. Kimmo Innanen at York Univeristy in Toronto,
working on models of the Galaxy's potential and mass,
and the orbits of retrograde stars.
22. 9. 2007 Janne Holopainen
defends his thesis work
Janne Holopainen's thesis defence took place in
the Quantum building (Physics Department) on Saturday
22/09/07 at 12:00. Janne's thesis is on "Investigations
of structure in dark matter halos" and his opponent is
Dr. Joakim Edsjö of the Department of
Physics, Stockholm University, and he was supervised by
Dr. Chris Flynn at Tuorla Observatory. Janne's
thesis work has covered several aspects of dark matter
--- on one hand the possibility (which he showed is
unlikely) that the dark matter of the Milky Way is in
the form of huge numbers of white dwarf stars. The
second part of the thesis concerned how dark halos could
affect lensing of galaxies seen at very large distances.
Link to further info in Finnish.
3-15. 8. 2007 Ali Talib
visits DARKSTAR
Professor Ali Talib Mohammed (Baghdad University,
Department of Astronomy) spent two weeks at DARKSTAR,
and was very welcome on what was his third trip to
Finland. We had discussions on imaging of exoplanets,
and Ali Talib held a talk on the topic.
3. 7. 2007 Laura Dunn
arrives at DARKSTAR
Welcome to Laura Dunn, who has taken up a
postdoctoral research position funded by the Academy of
Finland. Laura has just completed her PhD at Mount
Stromlo Observatory in Canberra, Australia, where she
worked on determining the distances to dwarf galaxies
via the surface brightness fluctation
method.
30. 6. 2007 DARKSTAR
goes to Wales
Darkstar members Janne Holopainen, Burkhard Fuchs, Erik
Zackrisson and Chris Flynn spent a week at a conference
in Cardiff on Dark Galaxies and Missing Baryons.
New South Welshman Chris Flynn was delighted to see
South Wales for the first time!
20. 5. 2007 Regner
Trampedach visits DARKSTAR
Regner Trampedach (Aarhus University) spent a week at
Tuorla Observatory discussing his 3-D models of stellar
atmoshperes, with Luca Casagrande and Chris
Flynn. Regner's visit was supported by funding from the
Academy of Finland.
1. 2. 2007 Esko Gardner
obtains PhD funding
Congratulations to Esko Gardner, who has
obtained long term funding towards his PhD studies from the
Finnish Graduate School in Astronomy and Space Physics.
20. 9. 2006 DARKSTAR
gains new funding via the Academy of Finland
Darkstarians Chris Flynn and Erik
Zackrisson have been awarded funding by the Academy of
Finland. Chris Flynn was awarded 105,000 euros to do
research on the distances to nearby dwarf galaxies,
while Erik has been granted funds for a three year
postdoctoral position.
1. 7. 2006 Esko Gardner
finishes Masters, starts PhD at DARKSTAR
Esko Gardner has completed his masters
work, having made a study of the abundances of elements
in stars of the Galactic bulge in comparison to nearby
stars. Esko used high resolution spectra obtained with
the European Southern Observatory's Very Large
Telescope. Esko has now started a PhD, and will be
working on topics in Galactic kinematics --- in
particular, the orbits of stars in the Galactic
disk. Welcome Esko!
2. 6. 2006 Johan
Holmberg takes up new position
Postdoc at DARKSTAR Johan Holmberg has taken a position
at Heidelberg, at the Max Planck Institute for
Astrophysics, working with Coryn Bailer-Jones on the
European Space Agency's GAIA mission. Congratulations
Johan!
May 2006 Luca Casagrande
and Johan Holmberg visit Stromlo.
PhD student Luca Casagrande and
postdoctoral researcher Johan Holmberg have visited
Chris Flynn at Mount Stromlo Observatory. The three
worked on helium and the lower main sequence
temperature scale with local experts.
2. 5. 2006 Luca
Casagrande awarded funding.
PhD student Luca Casagrande has been awarded funding for
the completion of his thesis work by the University of
Turku. Congratulations Luca!
2. 5. 2006 Chris Thom's PhD
accepted
The PhD of Chris Thom has been
accepted by Swinburne University of Technology. Chris was
supervised by Brad Gibson and Chris Flynn. More on Chris's PhD
topic below...
1. 4. 2006 Johan Holmberg obtains
post-doc position
DARKSTARian Johan Holmberg has
accepted a post-doc position at the Max Planck Institute in
Heidelberg, to begin in June 2006, where he will be working on
the European Space Agency's GAIA mission. Johan will be visiting
Chris Flynn in May in Australia before taking up this prestigious
position.
14. 3. 2006 Chris Thom completes
thesis work
DARKSTARian Chris Thom has completed
work on his PhD thesis. Chris worked on high velocity clouds
around the Milky Way, obtaining distance limits for a particular
cloud complex. Distances of this sort have been sought for
decades but have only just become possible to make using very
large aperture telescopes, and Chris' work is breaking new ground
in this area. Chris has also been offered a post-doc position at
the University of Chicago. Well done Chris!
8. 3. 2006 Luca Casagrande and
Rami Rekola obtain funding
DARKSTARians Luca Casagrande and Rami Rekola have obtained
funding from the Magnus Ehrnrooth foundation. Luca will be using
the funding to visit Chris Flynn at Mount Stromlo Observatory, in
Australia, as part of collaborative work on the effective
temperature scale of cool stars. Rami is doing work on the
distances to nearby galaxies. Well done Luca and Rami!
15. 2. 2006 Johan Holmberg
granted ESO time
DARKSTAR member Johan Holmberg has been granted
time on the ESO 2.2 meter telescope to use the FEROS instrument
for spectroscopy of Solar Analog stars. This work is related
to our study, just out, on the
Solar colours.
1. 1. 2006 Chris Flynn
on leave at Mount Stromlo Observatory
Chris Flynn is spending the year
2006 at Mount Stromlo Observatory, thanks to
a funding grant by the Academy of Finland.
31. 10. 2005 DARKSTAR
welcomes Erik Zackrisson
DARKSTAR is very pleased to welcome
Erik Zackrisson. Erik comes to us from Uppsala in
Sweden, where he has recently completed a PhD on dark
matter, gravitational lensing and the evolution of
galaxies.
23. 9. 2005 DARKSTAR
welcomes Esko Gardner
DARKSTAR is very pleased to welcome
Esko Gardner to the team. Esko is working with Johan Holmberg
for a Masters Thesis --- on high resolution spectra of bulge
stars obtained at the European Southern Observatory's
Very Large Telescope. Welcome Esko!
22. 9. 2005 Raul Jimenez and Licia Verde visit
DARKSTAR
Raul Jimenez and Licia Verde, of the University of
Pennsylvania, visited Tuorla Observatory on 22nd, September 2005,
when we had the chance to discuss dark matter and dark energy.
Raul gave us a great seminar on the ACT telescope, which will examine a small
area of the microwave background sky at high resolution, and constrain
cosmological models no end!
8.2004 Chris Thom visits the
DARKSTAR group.
Chris works on high velocity clouds and
distant stars in our galaxy, and completed
a study of said star while finally enjoying some warm
weather in Finland.
25. 4. 2005 DARKSTAR
welcomes Pasi Nurmi
DARKSTAR is very pleased to welcome
Dr. Pasi Nurmi to the team. Pasi works on the European
Space Agency's GAIA mission, and is a member of the
Double and Multiple Stars Working Group and the
Photometry Working Group. Pasi has been working on the
image data processing and in particular has developed an
algorithm to combine several patches into one
image. Pasi's scientific interests also cover
Gaia-related double star simulations, binary evolution
and galaxy modelling.
2-3. 3. 2005 Erik Zackrisson visits DARKSTAR
Erik Zackrisson from the University of
Uppsala visited Tuorla Observatory 2.-3. March 2005
and discussed dark matter and galaxy evolution with
the DARKSTAR research group. He also gave us
a seminar on the case for dark matter in compact
objects.
10. 1. 2005 DARKSTAR
welcomes Burkhard Fuchs to the team
We are pleased to announce that
Burkhard Fuchs has joined DARKSTAR as our corresponding
consultant. Burkhard is based at the Astronomisches
Rechen-Institut in Heidelberg, Germany. He brings great
theoretical flair to the team, with his research
interests in dark matter, disk galaxies, chemical
evolution and stellar kinematics.
January 2005 Students a-travel
DARKSTAR PhD students Luca Casagrande
and Janne Holopainen are travelling in January; Luca to
Pennsylvania to work with Professor Raul Jimenez on
Helium in K dwarf stars, while Janne will be going to
Potsdam to work with Dr. Alexander Knebe on dark matter
in galactic halos.
2.1.2005 Staff movements
Congratulations to DARKSTAR member Eira
Kotoneva, who has accepted a position as a medical
physicist at the University Hospital in Turku. We wish
her well in her new career.
10.2004 Chris Thom, Johan Holmberg and
Chanda Jog visit DARKSTAR
October is a busy month with long and
short term visitors to the DARKSTAR resaerch
group. Chris Thom and Johan Holmberg are collaborating
on studies of the stellar halo of the Galaxy. Chanda Jog
came to discuss the mass distribution of the gaseous and
stellar components of disk galaxies.
9.2004 Chris Flynn
spends one month in Heidelberg at the
Astronomisches-Rechen Institut
Collaborative work on the structure of
the Galactic halo and the dark matter in low surface
brightness galaxies was undertaken with Burkhard
Fuchs.
2-16.8.2004 Agostino Renda
visits DARKSTAR
Agostino is working on simulations of
galaxy formation with the Astrophysics and
Supercomputing group at Swinburne in Melbourne,
Australia, and particularly on the structures which are
remnant from the very earliest evolutionary phases, the
so-called stellar halos.
16.6.2004 Luca Casagrande obtains renewed funding
Luca Casagrande has been awarded a 6 month renewel of
his CIMO
fellowship. Luca began his PhD studies in the
DARKSTAR research group in October 2003, working
on Helium production in the Universe.
1.6.2004 Dr. Johan Holmberg to take postdoc position
at DARKSTAR
Johan has been a frequent visitor to the
DARKSTAR group, and we are pleased that he will now join
us for a two year postdoc position funded by the Academy
of Finland. Johan has worked on the mass of the Galactic
disk, as well as its kinematic, age and chemical
properties.
11-16.5.2004 Jesper Sommer-Larsen visits DARKSTAR
Jesper
Sommer-Larsen (TAC/NORDITA) visited DARKSTAR. Jesper works on,
among other things, simulations of galaxy and galaxy cluster
formation in full cosmological context; we were treated to some
very impressive movies from his latest supercomputer
runs!
22.4.2004 Laura Portinari
awarded Academy position.
Congratulations to DARKSTAR group member
Dr. Laura Portinari, who has received a three year position
funded by the Academy of Finland. Laura works on disk galaxies
and stellar and galactic chemical evolution.
10.2.2004 Janne Holopainen
obtains funding.
Congratulations to Janne Holopainen for obtaining
a one year stipend form the Magnus Ehrnrooth foundation for his
PhD studies. Janne is studying various scenarios for dark matter
in the milky way.
10.2.2004 Chris Thom visits the
DARKSTAR group for two months.
Chris
works on high velocity clouds and distant stars in our
galaxy. Chris visits us from the Astrophysics and Supercomputing
Centre at the University of Swinburne in Melbourne,
Australia.
2.2.2004 Laura Portinari joinsthe
DARKSTAR group
Dr. Laura Portinari has taken up a postdoc
position with the DARKSTAR group (Laura comes to us from the
Theoretical Astrophysics Center in Copenhagen). Among other
things, Laura works on disk galaxies; their formation, evolution
and baryonic content. She is supported by the Academy of
Finland.
30-31.10.2003 DARKSTAR presents its results at the final seminar of
the
ANTARES research program
The Academy of Finland
and Tekes' ANTARES program held the final seminar of the three year
program at
Finlandia Talo in Helsinki. DARKSTAR presented the results of the
program
highlighting baryonic dark matter searches; massive black holes in the
Galactic
halo and Helium production in the cosmos. We also showed our results at
the
Space 2003 exhibition at the old Cable Factory in Helsinki.
1.10.2003 Luca Casagrande
to
do his Ph.D. with DARKSTAR
Luca Casagrande has joined
the DARKSTAR group and will
be undertaking his PhD at Tuorla Observatory; he will be working on
Helium
production in the cosmos. Welcome Luca!
4-12.10.2003 Burkhard
Fuchs
visits DARKSTAR
Professor Burkhard Fuchs
(Astronomisches
Rechen-Institut, Heidelberg) visited Tuorla Observatory, and held a
seminar on
striking, and unexpected, structures in dark matter
halos.
18-19.9.2003 Laura
Portinari visits the DARKSTAR group
Laura Portinari
(Theoretical
Astrophysics Center, Copenhagen) visited Tuorla Observatory. We are
hoping
that Laura will be joing the DARKSTAR group in early 2004 for a
post-doctoral
fellowship supported by the Academy of Finland.
12.9.2003 DARKSTAR awarded funding
The Academy of Finland has
awarded a 120,000 euros to the DARKSTAR research group for the period
1.1.2004-31.12.2006. The grant is to be used toward research on the
"Baryonic matter content of disk galaxies".
9.9.2003 Luca Casagrande
awarded CIMO fellowship.
Luca Casagrande has been awarded a
fellowship to study in Finland by CIMO, the Centre for
International Mobility. Luca is to
start his PhD in October 2003 in the DARKSTAR research
group, and will work on Helium production in the Universe.
18-19.8.2003 Luca Casagrande visits the
DARKSTAR group
Luca Casagrande (University of
Turin, Italy) visited Tuorla. Luca has just completed a masters thesis
on comparisons between clustering in CDM cosmologies and large galaxy
redshift surveys such as carried out be the CfA.
2.6.2003-12.6.2003 Chris Brook visits the
DARKSTAR group
Chris Brook (Swinburne University
of Technology, Melbourne, Australia) is carrying out detailed
supercomputer based simulations of the formation of the Milky Way and
disk galaxies. He is visiting Tuorla as part of a grant for researchers
from Australia, Finland and Germany from the Australian Research
Council.
4.5.2003 Janne
Holopainen starts Ph.D. in the DARKSTAR group
Janne Holopainen is to do his Ph.D.
on studies of white dwarfs and dark mattter in the Milky Way. He is
testing ideas in the literature which have
been proposed to explain the so-called microlensing results carried
out over the last decade and which are the closest evidence we have
to a direct detection of dark matter in the Galaxy. Janne will be
visiting
Swinburne University of Technology (Melbourne) in July/August 2003
to work with Prof. Brad Gibson's research group
1.3.2003 Janne Holopainen completes M.Sc. on
Galactic dark matter
M.Sc. student at Tuorla
Observatory, Janne Holopainen, has completed work on a
pro gradu toward
his Masters thesis. He has placed new and interesting constraints on
the number of white dwarfs which could form part of the solution to the
dark matter mystery in the Milky Way.
6.2002 Academy grant for Prof. Brad Gibson
to visit Tuorla Observatory
The Academy of Finland has awarded
a small grant to finance a visit by Prof. Brad Gibson to Tuorla
Observatory in the summer of 2003.
5.2002
Chris Flynn awarded Academy of Finland senior researcher position
Dr. Chris
Flynn has been awarded a 5 year Senior Researcher position by the
Academy of Finland. These prestigious positions enable the awardee
to undertake pure research without teaching or administrative duties!
Flynn spent part of the first year of the position on sabbatical leave
at the Swinburne University of Technology's Astrophysics and
Supercomputing Centre in Melbourne, Australia.
14.1.2002 Eira Kotoneva awarded Ph.D. on
chemical evolution of the Milky
Way
Eira Kotoneva has successfully
defended her Ph.D. thesis, in
which she measured the amount of heavy elements in a fair sample
of nearby K dwarf stars; the study confirmed the old bugbear in
galactic
evolution of the G dwarf problem --- it is now known to hold in K
dwarfs selected in a narrow mass window, a significant improvement on
previous work. We believe this is the best available metallicity
distribution constraint on chemical evolution models of the
galaxy. Eira's
opponent was Professor Birgitta Nordström (Copenhagen/Lund).