Thüringer Landessternwarte Report on Activities (2017 to 2020) for the Scientific Advisory Council
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Thüringer Landessternwarte
Report on Activities (2017 to 2020)
for the
Scientific Advisory Council
1. Introduction
This report summarizes the activities of the Thüringer Landessternwarte since the last
visit of the Scientific Advisory Board (Wissenshaftlicher Beirat) in February 2017.
The Thüringer Landessternwarte (TLS) is a state funded astronomical research institute
that was re-founded in 1992 after the unification of Germany. It has a total staff
(permanent, administration, postdocs, students) of approximately 40 persons.
TLS has two major research departments:
• Stars and Planets
o Exoplanets (Staff: Guenther, Hatzes, Postdocs: Chaturvedi,
Döllinger, Esposito, Hartmann, Nagel; PhD: Sabotta, Wöckel)
o Star Formation and Jets (Staff: Eislöffel, Stecklum; PhD: Sperling,
Wolf)
o Stellar Pulsations (Staff: Lehmann; PhD: Pertermann)
o NEOs (Staff:Stecklum; Postdoc: Melnikov)
• Extragalactic
o Gamma Ray Bursts (Staff:Klose; PhD: Nicuesa Guelbenzu,
Schmidl)
o Galaxy Clusters - Radio/LOFAR: (Staff:Hoeft; Postdoc: Drabent)
2. Personnel
The Thüringer Landessternwarte has 8 base funded permanent research staff positions
including the director. In 2018 staff scientist Prof. Dr. Helmut Meusinger retired. As of this
February 2020, the position has not been filled, but a suitable candidate to work in the
field of radio astronomy in order to strengthen our LOFAR group is being recruited. TLS
will face staffing challenges because by mid-2023 three additional staff scientists will
retire including the director. This means that within the time span of a little more than 5
years 50 % of the permanent research staff of TLS will have retired. This vacating of
positions presents challenges as well as opportunities. It is important that this does not
impact our productivity as an institute.
The institute has 7 Postdoctoral staff positions all funded through third-party funds: DFG
(4), BMBF (2), ESA (1). This large number of Postdocs is one of the more pleasant
developments in the past decade. Ten years ago we typically had no more than 1-3
Postdocs.
We currently have 9 PhD students and 2 Masters students. In spite of our remoteness,
the past few years at TLS we have seen an increase in the number of students from
Friedrich Schiller University (FSU) doing their Masters work. One advantage of TLS is
that it offers students study in diverse fields (exoplanets, star formation, stellar activity,
stellar pulsations, gamma ray bursts, galaxy cluster, radio astronomy). FSU benefits from
this as it strengthens the astronomy aspect of the Physics and Astronomy Faculty and
makes the university more attractive for undergraduate and graduate studies.
In 2020 our entire IT department (two persons) will go into retirement, the first (Bernd
Fuhrmann) in June 2020 and the second (Jörg Schiller) at the end of 2020. Given the
importance of computers for research as well as software development for telescope and
instrument control it is crucial that we find capable replacements. The Fuhrmann position
has already been filled by Dr. Matthias Ball who did his Master's thesis at TLS, building
the multi-object spectrograph TAUMOK. He comes from Carl Zeiss Jena where he was
2
responsible for the software of the Aristarchus Greek National Telescope, the 2m
telescope built by CZJ. We will soon advertise for the second position.
In January 2020 we advertised for a staff position with a joint full professorship in Faculty
of Physics and Astronomy at the Friedrich Schiller University in Jena. The successful
candidate will head the research division at TLS on "Stellar and Planetary Systems". The
Thuringian ministry funded this position through a temporary increase of our budget as
part of our strategic plan (see below) to become a member of the Leibniz Society via a
branch of the Astrophysical Institute Potsdam (AIP). If the application to the Leibniz
Society is successful, this position will be funded permanently through the larger institute
budget (half funded by the federal government). A replacement for the director will be
made on his retirement mid-2023. Should this application fail, the continued funding of
the position will occur through the permanent institute position of the director. In short,
should TLS not become part of AIP, the new professor will assume the position of director
after 2023.
Funding for a temporary research group for radio astronomy has been made available by
the Thüringer Ministerium für Wirtschaft, Wissenschaft, und Digitale Gesellschaft
(TMWWDG, Thuringian Ministry for Economy, Science, and Digital Society). This
research area allows to build up, in cooperation with the DLR institute for Data Science in
Jena, expertise in data intense radio astronomy, a topic which is of large interest for the
German astronomical community with respect to LOFAR, MeerKAT and the SKA, and
which is complementary to fields of technological development covered by the AIP. The
search for suitable postdocs and PhD students to fill the positions is underway.
3. Institute Funding
The operations and research at TLS are funded through a combination of a fixed budget
from the State of Thuringia (base budget) and variable third-party funds (grant money).
3.1. Base Budget
Table 1 summarizes the institute base budget 2016-2020. The large increase in 2020 is
part of the short-term build up as part of the strategic plan to merge with Astrophysics
Institute Potsdam (AIP). It is important that the TLS budget remains at this level should
the merger with AIP not be successful.
Table 1: TLS budget 2016-2020
2016 2017 2018 2019 2020
[€] [€] [€] [€] [€]
1.929.800 1.972.600 2.039.400 2.093.700 2.536.700
It is instructive to compare the development of the institute budget since 2000 (Figure 1).
Between 2000 and 2019 the institute budget has increased by about 50 %, an average
annual increase of about 2.5 %. The mean inflation rate over this time was 1.5 % and
annual salary increases amounted to 2-3 % per year. In short, the TLS base budget has
been more or less constant since 2000 when factoring in inflation. In 2020 the budget is
what it would have been given a modest yearly increase of only 4 % over the past 20
years, marginally above the mean rate of inflation.
3
Figure 1: TLS budget 2016-2020
3000000
2500000
2000000
Euro
1500000
1000000
500000
0
3.2 Third-party Funds
Third-party money (grants) is a vital source of funding for supporting our research
activities and an important metric to gauge our productivity. Table 2 summarizes the
sources of external funding over the past five years. These have been separated
according to sources from the Deutsche Forschungsgemeinschaft (DFG) +
Bundesministerium für Bildung und Forschung (BMBF) + Deutsches Zentrum für Luft-
und Raumfahrt (DLR) + Deutscher Akademischer Austauschdienst (DAAD) and state
funding from Thuringia. In addition, we have separated third-party funds received related
to our LOFAR project.
Over the past five years the level of third-party funds have averaged 860.000 € or 43% of
the institute budget. The year 2019 was a banner year in terms of "profits" and marked
the first time that our annual intake from grant money exceeded 1 million Euro (57 % of
the base budget). These third-party funds are crucial for the institute as there are no
funds in our base budget to hire PhD students or Postdocs.
Table 2: Third-party funds over the past 5 years
2015 2016 2017 2018 2019
[€] [€] [€] [€] [€]
DFG 190.537 232.079 252.165 297.849 554.315
BMBF + DAAD + DLR 234.077 267.974 308.372 134.080 268.229
Thuringia 16.500 73.000 411.283 17.356 41.353
LOFAR (DFG, BMBF) 33.554 124.633 27.542 83.740 86.740
EU 0 0 0 70.147 165.412
Misc. 0 0 0 0 19.800
Total 474.668 697.686 999.362 603.354 1.135.849
4
Figure 2: Development of the Third-party funds 2000-2019
1200000
1000000
800000
Euro
600000
400000
200000
0
It is of interest to see the development of third-party funds in the past 20 years (Fig. 2)
especially in light of a level base budget. Since 2000 third party funding has increased by
490 %, or a mean annual rate of 25 %. In the past 5 years the annual rate was almost 30
%. TLS has leveraged its modest base budget into a total "operating" budget of 3.2
million Euros in 2019.
We expect to maintain a high rate of third-party funds at least over the next three years.
Several important research grants have been submitted and pending a decision from the
funding agencies:
CARMENES DFG Research Unit 3544: "Blue Planets around Red Stars: Scientific
Exploitation of the CARMENES Survey" between TLS, IAG in Göttingen, MPIA
Heidelberg, and the Hamburg Observatory (Speaker: A. Reiners (IAG), Vice-speaker: A.
Hatzes (TLS)). This is a three-year renewal of the successful first phase funding. TLS
heads project P4: Planet Survey and Multi-Planet Systems and is a co-Investigator on
P6: Transiting Planets with TESS. TLS is requesting a Postdoc and one PhD position.
The defense is scheduled for 19-20 March 2020.
DFG priority program SPP1992: "The Diversity of Extrasolar Planets". Projects from this
three-year renewal of this priority program are scheduled for review in May 2020. In the
last round TLS received 3 Postdocs and 1 PhD student. Proposals for 5 postdocs have
been submitted for the next round.
Research Training Group GRK 2615/1: "Gravitational Waves and Neutron Stars in
Multimessenger Astrophysics" (PI: Prof. Dr. Bruegmann, FSU Jena). This training group
is between the Theoretical Physics Institute, Friedrich Schiller University, Astrophysical
Institute and University Observatory, Jena, the Helmholz Institute, Jena, and TLS (Dr.
Klose). A successful defense was made in February with the recommendation by the
referees for the funding for 12 PhD positions. The final decision from the DFG senate is
expected in May 2020.
BMBF Verbundprojekt: “D-LOFAR 2.0, Enabling radio astronomy at lowest frequencies”
(PI: Prof. M. Brüggen, University Hamburg). This proposal aims at realizing LOFAR 2.0 in
5Germany together with Universities in Hamburg, Bielefeld, Bochum and Würzburg and
with the AIP. TLS (Dr. Hoeft) requested the upgrade to the LOFAR station (400,000 Euro)
and a software developer.
BMBF Verbundprojekt: “D-MeerKAT-II, A German Contribution to the Advancement of
Radio Astronomy at Centimetre Wavelength” (PI: Prof. D. Schwarz, University Bielefeld).
The proposal aims at enabling the German astronomical community to address the
scientific and technological challenges of modern radio astronomy. The consortium
comprises 11 partners. TLS (Dr. Hoeft) has requested one software developer.
Nationale Forschungsdateninfrastruktur (NFDI) (coordinated by DFG): "Astro-NFDI:
Astronomy, Astrophysics, and Astroparticle Physics within the NFDI” (PI: Prof. M.
Steinmetz). TLS is co-applicant institution, Dr. Hoeft is co-spokesperson. TLS requested
1.7 positions.
4. Publications
The amount of publications is another important metric for assessing the performance of
a research institute. Table 3 summarizes the number of publications of TLS since the last
meeting of the scientific advisory council. The year 2019 marked a record with 72
refereed publications (including a refereed book). The complete list of peer-review
publications over the past three years appears in the appendix. The publication rate of
the institute is consistently high with an average of 59 papers per year over this time
span, or about 5.4 papers per PhD scientist per year. This is an exceptional level of
productivity given the small size of our institute.
Table 3: Publications from TLS 2012 - 2016
Type 2017 2018 2019
Peer Review 37 68 71
Conference Proceedings 215 309 177
and Circulars
Books 1
Figure 3 shows the distribution of research papers 2017-2019 according to the main
areas of research at TLS: Exoplanets, Stars (including star formation) and Extragalactic.
It shows a good balance across all the three fields.
Figure 3: Publication according to research area in percent
Exoplanets
29 40 Stars
Extragalactic
31
6It is also instructive to look at the historical development of publications at TLS. In the
past 20 years we have seen a 255 % increase (13 % per year) in the annual number of
refereed publications. The TLS papers written during this time have received over 40,000
citations. Keep in mind that this has been accomplished with a fixed-sized permanent
staff over this period. The dramatic increase of our publication rate is clearly correlates
with the steadily increasing grant money coming into the institute.
Figure 4: Refereed Publications from TLS 1992-2019
80
70
60
50
40
30
20
10
0
5. Memberships in Consortia, Collaborations, and Cooperations
Below are the major consortia, collaborations, and cooperations, which are regulated by
contracts, Memoranda of Understanding (MoUs), or Letter of Agreements.
Academic Cooperations: TLS has a cooperation agreement with the Friedrich Schiller
University (FSU) and the University Leipzig (UL). The director at TLS also holds a faculty
position in the Physics and Astronomy Department at FSU and Prof. Dr. Helmut
Meusinger (TLS, retired) holds a professorship at UL.
CARMENES: The CARMENES consortium was formed to build and operate the
CARMENES spectrograph at the 3.5-m telescope at Calar Alto. It consists of 5 Spanish
institutes: Institut de Ciències de l'Espai (Barcelona), Universidad Complutense de
Madrid, Instituto de Astrofísica de Andalucía (Granada), Instituto de Astrofísica de
Canarias, Centro de Astrobiología (Madrid), Centro Astronómico Hispano-Alemán (Calar
Alto) and 5 German institutes: Max Planck Institute for Astronomy (Heidelberg),
Hamburger Sternwarte (Hamburg), Institut für Astrophysik (Göttingen), Landessternwarte
Königstuhl (Heidelberg) and TLS (Tautenburg). Hatzes is currently a member of the
Science Committee. More information on CARMENES can be found below.
CRIRES+: The CRIRES+ consortium was formed to fund and build the CARMENES+
spectrograph for the 8-m VLT at Paranal. Tautenburg is the lead institute (PI: Hatzes).
7The other members include Institute for Astrophysics, Göttingen (Co-I: Reiners) Uppsala
University, Sweden (Co-I: Piskunov) and INAF-Acetri, Italy (Oliva). After completion of
instrument commissioning the CRIRES+ consortium will coordinate and manage the
guaranteed observing time of 62 nights granted to the consortium.
EGAPS: The European Galactic Plane Surveys (EGAPS) consist of multi-band
UBgriHalpha galactic plane optical surveys IPHAS and UVEX carried at with the Isaac-
Newton Telescope on La Palma and the southern survey VPHAS+ carried out as an ESO
public survey at the VST on Paranal. TLS (members Dr. Eislöffel and Dr. Stecklum) was a
partner in the procurement of the large Halpha narrow-band filter for the focal plane of
the VST.
ENGRAVE: ENGRAVE stands for Electromagnetic counterparts of gravitational wave
sources at the Very Large Telescope. This international collaboration brings together over
250 scientists who use all the instrumental resources at the European Southern
Observatory (ESO) to perform rapid optical/near-infrared as well as sub-mm follow-up
observations of gravitational wave events, and to provide theoretical interpretations. The
main goal of ENGRAVE is to search for kilonova emissions that follow neutron star -
neutron star mergers related to LIGO/Virgo gravitational-wave events.
ESA_NEO: In 2010 TLS joined the worldwide effort to identify and track near earth
asteroids (NEAs), i.e. asteroids that might be harmful to Earth. Measuring additional
positions for objects recently detected by dedicated surveys is crucial for refining their
orbits. This activity is coordinated within the NEOCP program of the Minor Planet Center
(MPC). In 2019 our contribution reached a new level for two reasons. First, the
commissioning of the new prime focus camera TAUKAM highly improved the efficacy of
the Schmidt imaging considerably, thus yielding both a larger number of observations and
better accuracy. Second, TLS became part of a European consortium which is led by the
Spanish enterprise DEIMOS Space and includes six more observatories that won a
contract issued by the European Space Agency ESA within their project "P3-NEO-I -
Observational support from collaborating observatories". This participation provides
funding for observational task and technical development as well as the exchange of
expertise and information. As of February 1, 2020 TLS submitted more than 17500
positions for newly discovered objects to MPC. Among those almost 11500 belong to
hitherto unknown NEAs.
GLOW: TLS is a founding member of the German Long Wavelength Consortium (GLOW)
which coordinates German LOFAR activities. Dr. Matthias Hoeft of TLS is a member of
the executive committee acting as secretary of GLOW.
International LOFAR Telescope (ILT): TLS contributes our LOFAR station to the
International LOFAR Telescope. As return of our investment TLS receives reserved
access to the LOFAR array.
Verein für datenintensive Radioastronomie e.V. (VdR): TLS is a founding member of
VdR, which has been established in Jena. The VdR has currently thirteen members and
coordinates the German efforts with respect to the Square Kilometre Array. Dr. Matthias
Hoeft of TLS is Schriftführer of the VdR.
D-LOFAR IV: This consortium supported by the BMBF aims to make a significant
contribution to the development of LOFAR. A software developer position is funded at
TLS.
HERMES: The HERMES Consortium was formed to build and operate the HERMES
spectrograph at the 1.25-m Mercator telescope at La Palma. It is led by the KU Leuven
and members include the Royal Observatory of Belgium, the Université Libre de
Bruxelles, the Geneva Observatory (Switzerland) and TLS Tautenburg (Germany).
8KESPRINT: KESPRINT is an international consortium with 47 members in 9 countries
(Germany, Austria, Italy, Spain, Sweden, Denmark, The Netherlands, USA, Japan). It is
devoted to the detection and characterization of transiting exoplanets found by space-
based missions. TLS is a founding member of KESPRINT and it helped draft the
Memorandum of Understanding governing the consortium. See below for more details
concerning KESPRINT.
PLATOSpec: The PLATOSpec consortium is comprised of Ondřejov Observatory (Dr.
Petr Kabath), Pontifica Universidad Católica de Chile (Prof. Leonardo Vanzi), and TLS
(Prof. Dr. Artie Hatzes, Dr. Eike Guenther) with the goal of constructing and operating a
high resolution spectrograph on ESO's 1.5-m telescope at La Silla, Chile for the follow-up
of PLATO discoveries. For more details on PLATOSpec see below.
European Fireball Network: In 2019 TLS entered into an agreement with the Ondřejov
Observatory in the Czech Republic to host a Spectral Digital Autonomous Fireball
Observatory (SDAFO) as node of the European Fireball Network (EFN, PI: Dr. Jiri
Borovicka). The goal of the EFN is to record fireball meteor events using a network of
cameras in the Czech Republic and Germany. Using triangulation the expected impact
site can be calculated and the area searched for meteorite fragments. TLS helped
provided a site and important technical support for the installation of SDAFO (Figure 5).
Although an SDAFO is automated, TLS can immediately address technical difficulties
with the camera
Figure 5: SDAFO at TLS
(Top) A fireball observed by
SDAFO showing its
spectroscopic capabilities.
(Lower right) The SDAFO
mounted behind the
guesthouse. (Lower left) The
first fireball observed from
the Tautenburg SDAFO.
5. Operation of Facilities
TLS operates two major facilities: the optical 2m Alfred Jensch Telescope (AJT) and a
station for the LOFAR radio telescope.
95.1 The Alfred Jensch Telescope
The AJT is operated in two modes: A Schmidt mode used exclusively during dark time
(no moon) for imaging and photometry of faint objects. It is equipped with the prime focus
camera TAUKAM. The coude mode is for high resolution spectral observations of stellar
objects during bright time using the coude echelle spectrograph.
5.1.1 The Prime Focus Camera: TAUKAM
TAUKAM is the new prime-focus camera for the Schmidt mode of the AJT. The 621k€
funding for the instrument was through a state program for the development of research
infrastructure in Thuringia. At its heart is a 6144 x 6160 pixel e2v CCD covering a field of
1.3 x 1.3 square degree, a four-fold increase over the previous detector (Fig. 6). The
instrument was commissioned at the end of 2018. Except for an intervention to solve a
communication issue and to improve the vacuum holding time, the instrument has worked
flawlessly. The filter unit will be equipped with Sloan Digital Sky Survey filters (u:3543,
g:4770, r:6231, i:7625, z:9134), broad V and various interference filters. A minor setback
occurred when the unit had to be sent back to the manufacturer for technical
improvements. It now works reliably and will soon be installed on the telescope.
Science programs utilizing TAUKAM include the Near Earth Object Confirmation Program
(NEOCP), variability studies of YSOs and very low-mass objects, Quasar/AGN
monitoring, and multi-color studies of GRB afterglows. These programs benefit from the
increased observing efficiency offered by TAUKAM. For instance the short read-out time
of TAUKAM led to a record of more than 800 measured positions of Near Earth Objects
during a recent NEOCP run. Improvements in the telescope control system now enable
the astronomer to observe a large mosaic of a field quickly and automatically.
Figure 6: Image of the Pelican Nebula recorded with TAUKAM
The red circle in the upper right
corner is the size of the full moon.
The green triangle in the upper left is
the field of view covered by the old
CCD detector
105.1.2 The Tautenburg Coude Echelle Spectrograph
The venerable Tautenburg Coude Echelle Spectrograph continues to make important
contributions to exoplanet and stellar variability studies. It is a grism crossed dispersed
echelle operating in three wavelength regions depending on the grism: 3400-5500 Å;
4700-7400 Å, 5380-9270 Å. An iodine absorption cell provides simultaneous wavelength
calibration for precise stellar radial velocity (RV) measurements. The instrument is
capable of an RV precision of 2-3 m/s on bright stars using the iodine cell.
In recent years, TCES was successfully used for Kepler and K2 missions follow-up
observations and the search for planets around A-F stars and K giants. Also various
eclipsing binaries, multiple systems and Algol-type systems have been investigated using
spectroscopic time series taken with TCES.
TCES is seeing increased use for the
follow-up of transiting planet
candidates from the Transiting
Exoplanet Survey Satellite (TESS)
mission. It can provide valuable
reconnaissance spectra to exclude
false positives, but it is also ideally
suited for confirming brown dwarf and
giant planets. Figure 7 shows the RV
confirmation of a rare transiting brown
dwarf (M = 51 MJupiter) TOI-503b
discovered by TESS. This discovery is
unique in that the host star is a
metallic line (Am) star. These RV
measurements were taken without the iodine Figure 7: Radial Velocity confirmation of the
calibration and they have a scatter of 90 m/s. transiting brown dwarf (M = 51 MJup) TOI-503b
made with the TCES on the AJT.
This precision was achieved in spite of the
fact that TOI-503 is an early type star with
few lines that are broadened by rapid rotation (30 km/s). This speaks for the intrinsic
stability of the spectrograph.
TCES can be a valuable instrument for the ground-based follow-up measurements of
discoveries from ESA's PLATO mission. However, the spectrograph is 20 years old and
spectrograph technology has advanced since then. A new spectrograph that is more
efficient, has broader wavelength coverage, less moving parts, and that is fiber-fed from
the telescope will make for a more powerful instrument for the ground based follow up of
PLATO discoveries.
5.1.3 Tautenburg as an astronomical site
Major upgrades were made to our weather monitoring equipment and these resulted in a
more efficient use of telescope time. These improvements include an all sky camera (Fig.
8) and a seeing monitor. These now enable us to make a quantitative assessment of
Tautenburg as an astronomical site.
The left panel of Figure 9 shows the histogram of the seeing as measured with the seeing
monitor. These have a median value of 1.7" and roughly 30 % of the time the seeing is
better than 1.5". The seeing values as measured at the telescope (right panel of Fig. 9)
11have a median of 2.7", so there are substantial improvements to be made in the area of
"dome" or "telescope" seeing. For instance, we find that the difference between the
telescope and true seeing correlates with mirror temperature. A better median seeing can
be gained with ventilation of the mirror and the interior dome.
It is of interest to compare Tautenburg to an excellent astronomical site like La Silla,
Chile. This is summarized in Table 4. "Spectroscopic Nights" refer to nights when at least
spectroscopic observations could be conducted even in less than ideal conditions (e.g.
light clouds). TLS is about a factor of two worse than La Silla in terms of clear time,
median seeing and sky brightness (approximately one magnitude fainter in all bands). In
terms of operating costs, running the 3.6-m telescope on La Silla is about a factor of 10
higher than for the AJT. In short, Tautenburg is a good site given its location (middle
Europe) and operating costs.
Figure 8: The night sky over Tautenburg recorded with the all sky camera
Figure 9: Histograms of seeing measurements
Seeing Monitor
(Left) Seeing measurements with the seeing monitor.
(Right) The seeing measured at the 2m telescope for coude and prime focus.
12Table 4: Tautenburg as an astronomical site compared to La Silla
Parameter Tautenburg La Silla
Spectroscopic Nights 38 % 80 0%
Median Seeing [arcsecs] 1.71 0.87
Sky Brightness [B] 21.5 22.7
Sky Brightness [V] 20.5 21.8
Sky Brightness [R] 19.9 20.9
Sky Brightness [I] 18.3 19.9
5.1.4 The Tautenburg International Observing School
A special niche of the AJT is its use in the training of advanced students in astronomy.
TLS is in an enviable position in that it has modest sized (2m) telescope with modern
instruments at a decent site that is easily accessible from central Europe. Furthermore it
is an "old style" telescope where students get hands on experience with telescopes and
instruments.
For these reasons in 2016 we started the Tautenburg International Observing School
(TIOS). It is two week course taught roughly every 2 years with each school alternating
between imaging and photometric observations (Schmidt Camera) and spectroscopic
observations (TCES). The goal of the school is to instill initiative, creativity and
independence in students and to
foster collaboration in young
scientists early in their careers.
Rather than given a set of
targets with problems to solve,
the students, in teams of 4-5
people, decide the science
case, the targets and then plan
and execute the observations.
At the end of the school each
team gave presentations on
their results. It is packed
program with lectures in the
afternoon, and observations (in
teams) at night. TIOS is
attractive in that 1) it furthers
Figure 10: Students and tutors from the 2018 Tautenburg the careers of young scientists
International Observing School. (a former student of the
observing school now has an
ESO fellowship, plus 2) it attracts bright students from around the world (a former student
from India is now working as an intern in Tautenburg).
The last TIOS took place in Fall 2018 (Fig, 10) and had 20 participants, 9 from Germany
and 11 international students (from the Czech Republic, Slovakia, the United Kingdom,
India, Ethiopia, Chile and Uganda). All travel for the students were funded by the DFG
Priority Program SPP1992: "The Diversity of Extrasolar Planets".
Students learned echelle spectral reductions and precise stellar radial velocity
measurements, detecting known exoplanets (left panel of Fig 11) with a precision better
than 4 m/s. One student (Jiri Zak) detected radial velocity variations in the low amplitude
Cepheid V824 Cass (right panel of Fig. 11). This was an especially challenging target due
to its faintness (V = 11.3). The students obtained a radial velocity precision of 175 m/s
13without simultaneous wavelength calibration which is excellent given the magnitude and
type of star. A publication is currently in preparation. 1 The students also performed
important tests of radial velocity measurements that appeared in the book The Doppler
Method for the Detection of Exoplanets (Hatzes 2019).
Figure 11: Results from the Tautenburg International Observing School
(Left) The RV variations of 51 Peg obtained by students from the TIOS (red) compared to
published values. The RV scatter of the Tautenburg measurements is 3.8 m/s. (Right) The
RV variations of the low amplitude Cepheid V824 Cass. Two pulsation modes were
detected. The rms scatter of 175 m/s is after removing two periods from the data.
The next TIOS may again (hopefully) be sponsored by the next round SPP1992 program.
We will also include observing schools in a planned proposal to the Research and
Innovation Staff Exchange (RISE) program of the Horizon 2020 program of the European
Union. This demonstrates the "added value" of such observing schools in terms of
including these as part of funding proposals to national and international programs.
5.2 LOFAR
The Low Frequency Array (LOFAR) is the largest radio telescope of the world with
stations connected via fast internet and separated by up to 2000 km. The international
LOFAR telescope (ILT) is comprised of 52 stations distributed over Europe with the core
in the Netherlands (Fig. 12). It observes in the mostly unexplored frequency range
between 10 and 240 MHz. LOFAR improves sensitivity and resolution by more than one
order of magnitude in comparison to preceding telescopes operating in a similar
frequency regime. This has allowed LOFAR to open up a new window to the Universe.
The array is still expanding. A new station in Latvia has been recently constructed and a
station in Italy is in preparation.
LOFAR has been primarily designed, built, and is now operated by the Netherlands
Institute for Radio Astronomy (ASTRON). There is a strong contribution by institutes in
other European countries. All LOFAR partners together form the International LOFAR
Telescope (ILT). Fourteen stations have been built outside of the Netherlands, six of them
in Germany. The Low Frequency Array has been recognized by the BMBF as a large
research infrastructure in Germany. The German institutes participating in LOFAR have
formed the German Long Wavelength Consortium (GLOW). Large amounts of data,
1A requirement of the class is that all students involved in the observations are co-authors on the
paper.
14currently more than 15 Petabytes, are stored at one site of the LOFAR Long Term
Archive.
Figure 12: The LOFAR network across Europe
Onsala
Birr Irbene
Dutch stations
Chilbolton Norderstedt Bałdy
Potsdam
Borówiec
Jülich
Effelsberg
Tautenburg Łazy
Nançay Unterweilenbach
Medicina
The TLS operates one of the six LOFAR stations in Germany. The TLS station was the
second international station to be commissioned and in 2019 TLS marked 10 years of
LOFAR operations. The institute receives funding for a software developer as part of D-
LOFAR IV project. This allows the TLS to make a significant contribution to the software
development (prefactor pipeline) and to contribute software within the Science Delivery
Framework led by ASTRON. The TLS participates in the LOFAR Two-Metre Sky Surveys
(LoTSS). It leads the data processing for LoTSS on the supercomputer JUWELS at the
Forschungszentrum Jülich. The TLS primarily uses its LOFAR engagement to study
diffuse emission in galaxy clusters, but also to investigate other topics such as young
stellar objects and extremely inverted radio sources.
6. Academic Teaching
6.1 Friedrich Schiller University
TLS scientists regularly teach astronomy courses at FSU. Prof. Dr. Hatzes holds a
professorship in the Physics and Astronomy Faculty at FSU and Meusinger at University
Leipzig. Courses that have been taught at FSU by TLS scientists over the past 5 years
(WS = Winter Semester, SS = Summer Semester):
WS 2016/2017
English for Scientists: Writing Better Research Papers and Proposals (Hatzes)
SS 2017
Physics of Planetary Systems: Detections and Properties (Hatzes)
Extragalactic Astronomy (Hoeft)
15WS 2017/2018
Radio Astronomy (Hoeft/Schreyer)
SS 2018
Physics of Planetary Systems: Detections and Properties (Hatzes)
Introduction to High Energy Astrophysics (Klose)
WS 2018/2019
Physics of Planetary Systems: Detections and Properties (Hatzes)
Extragalactic Astronomy (Hoeft)
SS 2019
Extragalactic Astronomy (Hoeft)
WS 2019/2020
Neuton Stars, Gamma Ray Bursts and High Energy Astrophysics (Klose)
6.2 University Leipzig
We also maintain a cooperation with the Physics Department of the University of Leipzig.
TLS has taken an active role in the conception of the astronomy curriculum at Leipzig.
Astrophysics I. Stellar Physics: Lectures + Seminar (Meusinger)
Astrophysics II. Extragalactic Astronomy: Lectures + Seminar (Meusinger)
6.3 Teaching Export: Africa
TLS is participating in development of astronomy in African countries. Through
collaborations with Mbarara University of Science and Technology (MUST) in Uganda
and the Ethiopian Space Science and Technology Institute (ESTI). ESTI has a new
observatory with two 1-m telescopes located at the 2700m on Entoto in Ethiopia. TLS is
advising ESTI on observations with its
high resolution spectrograph and
possible science projects.
Staff scientist E. Guenther has
travelled to Ethopia and Uganda to
give courses in order to strengthen
their astronomical departments (Fig.
13). He serves as an advisor to
several PhD students in both countries Figure 13: Eike Guenther with students in Ethopia
including the first PhD in astronomy
awarded in Ethiopia.
6.4 Diploma, Bachelors and Masters Theses (2017-2020)
6.4.1 Masters Theses
Completed:
Silvia Kunz: The influence of bright stellar regions (plage) on planet diameter
measurements
Sarah-Jane Köntges: Analyse der CARMENES Beobachtungen des Zwergsterns GJ172
16Lara Hartung: The CARMENES O\observations of GJ205: A false planet case study
David Wöckel: Echelle spectroscopy and analysis of MASCARA-1b, an extremely hot
exoplanet orbiting an A-star.
On-going:
Simon Oberhauser: Diffuse radio emission in the merging galaxy cluster Abell 1367
Ludwig Pfeifer: Inverse Compton Ghosts: A joint analysis of the 4XMM DR9 and LoTSS
source catalogues
6.4.2 PhD Theses
Completed:
Alexander Drabent: Diffuse radio emission at low frequencies in merging galaxy clusters
Cosmos Dumba: Extended diffuse radio emission in merging galaxy clusters
Jakob Gelszinnis: Radio relics: A joint analysis of surveys and simulations
Michael Hartmann: The mass dependence of planet formation: A radial velocity survey for
extrasolar planets around F and Ap stars
Kamlesh Rajpurohit: Diffuse radio emission and magnetic fields in galaxy clusters
Daniel Sebastian: Transiting Sub-stellar Companions of Intermediate-mass Stars
On-going:
Priscilla Muheki: Flares and coronal-mass-ejections of the two active M-Star AD Leo and
EV Lac (Remote supervision of student at Department of Physics, Mbarara
University of Science)
Ana Nicuesa Guelbenzu: Radio observations of host galaxies of short Gamma-Ray
Bursts
Frank Pertermann: Long-term monitoring of oscillating Algol-type stars
Silvia Sabotta (neé Kunz): Tautenburg-Ondřejov radial velocity follow-up for transiting
planetary systems of stars with different masses.
Sebastian Schmidl: Gamma-Ray Burst Supernovae
Thomas Sperling: Untersuchungen von Klasse I-Jets mit SOFIA
Verena Wolf : Analysis of circumstellar accretion disks by means of radiative transfer
modeling
David Wöckel: The erosion of planetary atmospheres.
7. Major Scientific Projects
TLS pursues a diverse range of astronomical topics. Here we summarize results from
some of the major ongoing scientific projects.
7.1 The CARMENES Project
The Calar Alto high-Resolution search for M-dwarfs with Exo-earths with Near infrared
and optical Echelle Spectrographs (CARMENES) is a fiber-fed Echelle spectrograph that
has a visual (0-1 µm) and a near infrared (1-1.7 µm) arm each with a resolving power of
17R (= λ/δλ) ≈ 90.000. It was developed, funded and built by a consortium of Spanish and
German institutes, including TLS who was responsible for the calibration units.
CARMENES is a unique instrument as the only high resolution spectrograph operating
simultaneously in visual and near infrared bands. The consortium received 750 useful
nights to carry out a radial velocity (RV) survey of planets around M dwarf stars,
particularly planets in the habitable zone.
The project has been running since 2016 and has been spectacularly successful having
discovered 19 exoplanets, five that are transiting (from the K2 and TESS missions). Since
2016 the project has produced 39 refereed papers. Figure 14 shows the planetary system
around Teegarden's star discovered with CARMENES. These are two earth-mass
planets with orbital periods of 4.9 and 11.4 days (Zechmeister2 et al. 2019).
CARMENES has also proven to be an effective instrument for the study of exoplanet
atmospheres having discovered He absorption in WASP-69 b (Nortmann et al 2018), HD
189733 b (Salz et al. 2018) and HD 209458b (Alonso-Florian et al. 2018).
The CARMENES survey ends in two years and the consortium is currently planning to
submit proposals for a legacy program on the Calar Alto 3.5m telescope as well as an
upgrade to the instrument that includes a blue arm.
CARMENES has been an important international project for TLS and we made a major
contribution with our development of the calibration units. It is crucial that TLS continues
to participate in the future of the CARMENES project. In particular, the development of a
blue arm to the spectrograph can open up possible collaborations with the optics
institutes and industries in Jena.
Figure 14: The Planetary System around Teegarden's Star
The RV variations due to the planetary system around Teegarden's star found by CARMENES.
Both planets have masses of 1 MEarth (from Zechmeister et al. 2019).
7.2 The KESPRINT Consortium
The KESPRINT grew from TLS's participation in the CoRoT Exoplanet Science Team
(CEST) along with DLR-Berlin Institute for Planet Research and Rheinisches Institut für
Umweltforschung (RIU) in Cologne. During CoRoT the GERMAN members of KEST built
a close and productive working relationship with each institute bringing their special skills
2 Mathias Zechmeister was a former Masters student at TLS.
18to the effort: TLS in the area of spectroscopic observations and precise stellar radial
velocity measurements, RIU in transit detections, light curve processing and transit timing
variations, and DLR in light curve modeling and transit detections. After CoRoT wanted
to apply our productivity and efficiency to light curves from K2 mission - thus KEST was
born!
KEST found that it often observed the same targets as a competing group, the ESPRINT
team. What started as an informal cooperation to make more efficient use of telescope
time led to a merger of the two groups, KESPRINT (the name simply reflects the original
group names). The KESPRINT consortium has grown into an international organization
with 47 full and 6 collaborative members in nine countries (Germany, Denmark, Spain,
Italy, Sweden, England, the United States, United Kingdom and Japan).
The KESPRINT mission is to help promote the exoplanet science interests of its
members and to play a leading role in the characterization of exoplanets. KESPRINT is
also strongly committed to promoting the careers of young scientists in the field of
exoplanets and to encourage initiative and creativity in their scientific endeavors.
Arguably, KESPRINT is the most successful team for the characterization (mass and
radius) of transiting candidates found by the space missions. Since 2015 it has
determined the mass of 36 transiting planet found by K2 and TESS resulting in 45
refereed publication. Included in this list is π Men c - the first transiting planet found by the
TESS mission (Gandolfi et al. 2018). This spectacular success is driven by two factors:
First, is our ability to get telescope time on some of the premier facilities in the world,
including a large program on ESO's HARPS spectrograph on the 3.6m telescope at La
Silla Table 5 summarizes the granted observing time that resulted from peer-review
proposals (with the exception of the Tautenburg AJT time). Most of the HARPS time
resulted from a successful large program. Second, KESPRINT is well-structured, well-
organized and efficient.
Figure 15 shows the exoplanets with well-determined masses and radii in the mass
density diagram. KESPRINT discoveries are in red circles and triangles. The KESPRINT
consortium has characterized (planet mass and radius) approximately 25 % of the known
exoplanets with masses < 10 MEarth.
Table 5: Telescope time allocated to KESPRINT 2017-2019
Instrument Telescope Granted observation nights
2017 2018 2019
HARPS@ESO 3.6m 16 18 47
HARPS-N@TNG 3.5m 17 6 15
Tull@McDonald 2.7m 28 16 16
FIES@NOT 2.5m 33 34 15
TCES@AJT 2m - - 35
HERMES@1.5m Mercator - - 5
ESPRESSO@VLT 11
KESPRINT has become a model in an effective and efficient follow-up program to confirm
transiting exoplanets. Its work is highly regarded by the Tess Follow-up Observing
Program (TFOP). The CHEOPS mission recently asked KESPRINT to join in its follow-up
efforts having recognized that it is one of the major groups for transit follow-up
observations. The work of KESPRINT can translate into a prominent role in the
international effort for the follow-up of discoveries made by ESA's PLATO mission.
19Through KESPRINT, TLS is also well poised to assume a leadership role in coordinating
the German PLATO follow-up efforts.
Figure 15: KESPRINT's planets in the mass-density diagram
Exoplanets with well-determined masses and radii in the mass-density diagram. Color
codes indicate the planet insolation in terms of the Earths' insolation. The red circles and
triangles represent KESPRINT confirmation of K2 and TESS transiting exoplanets. Stars
represent solar system objects.
7.3 CRIRES+
CRIRES+ is a major upgrade to the successful instrument CRIRES (CRyogenic InfraRed
Echelle Spectrograph) which was installed at one of the 8-m Very Large Telescope (VLT)
UTs at the Paranal Observatory of the European Southern Observatory. CRIRES+ was
built by TLS (PI Hatzes), the Institute for Astrophysics Göttingen (CoI Reiners), Uppsala
University (Sweden, CoI Piskunov), INAF Acetri (Italy) and ESO. Funding was provided
by the Federal Ministry of Education and Research (Germany) and the Wallenberg
Foundation (Sweden). For their investment the CRIRES+ consortium will receive 62
nights of guaranteed time (GTO) starting in Fall 2020 or early 2021.
The GTO time will be apportioned among these three science cases:
• A search for super-Earths in the habitable zone of low-mass stars and brown
dwarfs
• The characterization of atmospheres of transiting giant planets
• The origin and evolution of stellar magnetic fields
The upgrade consisted of an entire overhaul of the cryogenic optics and turning the old
CRIRES into a cross-dispersed echelle spectrograph. The major upgrades of the
instrument include:
1. Increased wavelength coverage by a factor of 10-15 in six IR bands
2. Modern HAWAII 2RG arrays
3. Absorption cells for precise radial velocity measurements (The left panel of
Fig.16)
4. A polarimetric unit for the measurement of stellar magnetic fields.
20Figure 16: CRIRES+ cells and in the integration hall
(Left) The absorption cell for the K-band. Grey regions are those outside the defined region of the
+
K-band. (Right) CRIRES in the ESO integration hall during close out testing and verification. One
can see the large cryogenic dewar in the center of the picture, the electronic racks behind it, and
parts of the warm optics table on the right.
Six cross-dispersing gratings are mounted a cryogenic wheel and each is optimized for
each of the Y, J, H, K, L and M bands. The resolving power is R = 100,000. CRIRES+ is
unique in many respects: It is 1) the only cross-dispersed echelle working at all IR bands,
2) the only high resolution IR spectrograph on an 8-m telescope, and 3) the only such
spectrograph in the southern hemisphere.
In January 2020 CRIRES+ was shipped to Paranal (see right panel of Fig. 16) and the
commissioning of the warm part was successfully completed in February 2020. Two
commissioning runs with the complete cooled system are planed in March and April 2020.
If all goes well the instrument will be offered to the community in Fall 2020 or 2021.
7.5 SOFIA and Star Formation
The Stratospheric Observatory for Infrared Astronomy (SOFIA) is a joint German-US
space science project comprised of a 2.7-meter telescope inside a modified Boeing
747SP (left panel of Fig. 17). This airborne observatory performs astronomical
observations in the infrared and submillimeter wavelengths.
TLS scientists have received extensive observing time on SOFIA since 2016 (Table 6)
primarily using the Faint Object InfraRed CAmera for the SOFIA Telescope (FORCAST)
or the Field Imaging Far-Infrared Line Spectrometer (FIFI-LS). Overall, TLS scientists
have participated in about 6 % of all SOFIA flights.
SOFIA is making tremendous strides in studies of accretion in massive young stellar
objects (MYSO). The right panel of Figure 17 shows the spectral energy distribution
(SED) of the massive young stellar object MYSO 6358 before and during the outburst as
recorded by SOFIA in the infrared. The burst could not be detected in the mid-infrared
since the source is embedded in a molecular cloud. Only with SOFIA observations could
the burst state be confirmed.
21Table 6: SOFIA time granted to TLS Scientists
Year PI Instrument Time
2016 Eislöffel FORCAST 1.8 hrs
2016 Eislöffel FIFI-LS 1.7 hrs
2017 Eislöffel FIFI-LS 6.4 hrs
2017 Stecklum FIFI-LS 1.1 hrs
2017 Stecklum FORCAST 0.9 hrs
2018 Stecklum FORCAST 0.9 hrs
2018 Eislöffel FIFI-LS 2.0 hrs
2019 Eislöffel FIFI-LS 4.6 hrs
2019 Stecklum FIFI-LS 2.2 hrs
2019 Eislöffel FORCAST 0.7 hrs
2019 Sperling FIFI-LS 3.3 hrs
2020 Sperling FIFI-LS 3.8 hrs
Figure 17: Inside SOFIA and the SED of MYSO G358
(Left) Image from within SOFIA taken during one of the FIFI-LS flights observing NIRS3. (Right)
The SED for MYSO G358 before (lower) and during the accretion burst (upper line). Because the
source is embedded only SOFIA could verify that it was in the burst state.
SOFIA is also providing important wavelength coverage in combination with other
facilities. The discovery of accretion in the young stellar object (YSO) NIRS3 in the high
mass star forming region S255IR was followed up by ALMA, VLA, VLT, and SOFIA.
These coordinated observations resulted in a number of important findings: 1) evidence
for disk-mediated accretion, 2) confirmation of the relationship between ejection and
accretion, 3) confirmation of the radiative pumping of class II methanol masers and 4) the
first evidence for the relocation of maser emission sites due a burst. Through the broad
wavelength of the observations we were able to reconstruct the burst history (Figure 18).
22Figure 18: The young stellar object NIRS3
Light echo from NIRS3 (center) with contours of the 145 MHz radio continuum
emission mapped with LOFAR. The image, based on Ks-band frames taken in 2015
Nov (blue) as well as 2016 Mar (green) and Nov (red), shows the light propagation.
The increase of the radio continuum from Feb 2017 (blue) to 2019 Nov (red) is
obvious while a nearby compact HII region remained constant.
7.2 GROND
The Gamma-Ray Burst Optical Near-Infrared
Detector (GROND) is a multi-channel camera,
allowing for simultaneous imaging in seven bands
(Sloan griz, near-infrared JHKs). GROND is
operated at the Max Planck 2.2m telescope on
ESO, La Silla. It was developed in close
collaboration between MPE Garching (former PI:
Dr. J. Greiner; present PI: Dr. A. Rau) and TLS
(CoI: S. Klose). During its construction process
(2001-2007), TLS invested approximately 250.000
Euro for buying hardware (1 IR detector and
computers), performed the optical design study,
and provided manpower for setting up additional
hardware components on the mountain (third
mirror (M3) unit and a light protection unit).
More than 10 years after first light (2007), GROND
is still a unique astronomical instrument world-
wide. Its technical specification is summarized in
Greiner et al. ESO Messenger 130, Dec. 2007. Figure: 19: GROND multi-color image of
GROND is healthy and performing well. At present the kilonova following a neutron star-
it is preferentially used by MPE Garching for a neutron star merger in NGC 4993
study of eROSITA X-ray sources, while TLS can
use GROND for short-GRB follow-up observations. Within the context of multi-
messenger astrophysics, particular emphasis is given to follow-up observations of
neutron star-neutron star merger events detected by gravitational wave observatories.
For this purpose, TLS members are also involved in the international ENGRAVE
23collaboration (Electromagnetic counterparts of gravitational wave sources at the Very
Large Telescope). Among the outstanding observational results obtained with GROND is
the imaging and follow-up of the very first optical counterpart of a gravitational wave
event, GW170817 (Fig. 19), which was published in two highly-quoted discovery papers.
7.3 SkyHopper and Space Optics
SkyHopper SkyHopper is a planned Australian CubeSat mission devoted to exoplanets,
Gamma-Ray Bursts, and cosmology (PI: M. Trenti, University of Melbourne), with
substantial contributions from TLS. The mission concept relies on a box-shaped near-
infrared telescope (10x20 cm) that can reach mAB=19.5 mag in a 10 min exposure (5
sigma detection). In combination with a newly developed beam splitter based on a
Kösters design (Fig. 20), it will provide simultaneous multi-color imaging in four bands (z,
Y, J, and H). Originally the project team was anticipating a launch date around the year
2020. However, because of funding problems in Australia the project is delayed and a
more realistic launch date is not before 2023.
Project funding so far includes about 1 million AUD from Australia, about 1 million USD
from Italy, and about 0.5 million Euros from Germany. The Australian funding covers the
costs for engineers currently working in Melbourne on technical aspects of the satellite
(thermal household, radio communication, etc.) as well as the costs for purchasing a
commercial CubeSat bus. The Italian contribution covers the complete launch costs.
Between 2016 and 2017 TLS, in collaboration with MPE Garching, was leading the
development of the design of the telescope. Since 2018, TLS has been in charge of the
development of the technological basis for the manufacturing of the sophisticated beam
splitter (designed by MPE Garching).
After successfully applying for funding by the Thuringian government in 2018, TLS and
the Fraunhofer-Institut für Optik und Feinmechanik (IOF) Jena established a research
group ("SpaceOptics"), which is paid by the European Social Fond (ESF) via the
Thüringer Aufbaubank (PI: S. Klose; see http://www.tls-
tautenburg.de/TLS/fileadmin/SpaceOptics/home). The group comprises the disciplines of
optical design, coating development, interlayer-free bonding technology, and mechanical
design.
The aim of the research group is to develop a technology platform for the construction of
the complex optical beam splitter for hyperspectral space applications and for innovative
laser technology. This beam splitter has never before been realized technologically,
although it has already gained considerable interest by world-leading optical companies.
Future applications of this beam splitter will be interesting for a broad spectrum in science
(e.g., remote sensing of the Earth, archaeology, astronomy) and economy (e.g., medical
technology, microscopy, mining industry, laser technology), i.e., applications that make
use of multi-color imaging techniques.
The research group is funded for a timespan of three years. It includes five young
engineers and scientists, with additional manpower and substantial technical support from
IOF and TLS. The progress of the work of the group is regularly evaluated by industry
(twice a year), including members from Carl Zeiss Jena GmbH, LensTec Jena GmbH,
Jena-Optronik GmbH, and Optics Balzers Jena GmbH.
Cube or nano-satellites have become a cost effective means for space-based scientific
studies. As of January 2020 over 1100 cube satellites have been successfully launched.
Currently, BRITE-Constellation is a mission of five cube satellites investigating stellar
structure and evolution of the brightest stars. The development of small, simple, yet
state-of-the-art optical instruments, like those for SkyHopper can be a "game changer" for
space-based astronomical observations with cube satellites. With SkyHopper TLS and
the Jena optical institutes have a foothold in this rapidly growing field.
24Figure 20: SkyHopper: Kösters prism and consortium
The Köster's prism providing the four band beam splitting for SkyHopper. (right) The institutes
involved in SkyHopper.
7.6 PLATOSpec
PLATOSpec is a UV-optimized high resolution spectrograph for the ESO 1.5m telescope
at La Silla (Fig. 21). It will be dedicated to the characterization of exoplanets found by
ESA's PLATO mission.
PLATO is an ESA flagship mission to detect exoplanets
around bright (mv < 11 mag) stars using the transit
method. Launch is planned for 2026. It is estimated that
PLATO will detect 4000 superEarth planets and 40-70 of
these will reside in the habitable zone of the host star.
These discoveries will require ground-based spectral
observations to 1) remove false positives, 2) measure the
planet mass via stellar radial velocity measurements, and
3) determine the stellar parameters (mass, radius,
temperature, abundance, etc.) of the host stars. The
telescope resources required for this are enormous. For
example approximately 50-100 radial velocity (RV)
measurements are needed to measure the mass of small
planets, particularly in multi-systems. In this respect small
telescopes dedicating 100 % of the telescope time to
these measurements can play an important role in the
follow-up of PLATO transit discoveries.
PLATOSpec will have a resolving power of R = 68,000
Figure 21: ESO'S 1.5m and cover the wavelength range 360 - 680 nm. Unlike most
telescope at La Silla RV instruments, PLATOSpec will be optimized for the UV
with an efficiency > 3% at the Ca II H&K lines (390 nm) which are important measures of
stellar activity, a phenomenon that often masquerades as a planet signal in RV data.
Wavelength calibration using an iodine absorption cell will achieve an RV precision < 3
m/s. The telescope and spectrograph will be operated remotely. PLATOSpec will be built
and operated by a consortium of three institutes: 1) TLS, 2) The Astronomical Institute
ASCR at Ondrejov, Czech Republic (ASU) and 3) the Universidad Catholica in Chile
(PUC). The PLATOspec project has been approved by the ESO council. A contract to
25refurbish the telescope and to equip it with a state-of-the-art operating system has was
signed with ProjectSoft company April 2020. These costs will be covered by ASU.
The current schedule for PLATOSpec is:
• Refurbishment of telescope dome: September to November 2020
• Refurbishment of telescope by ProjectSoft: January 2021
• Telescope ready: June 2021
• Preliminary design review PLATOSpec: July 2021
• Final design review: January 2022
• Spectrograph construction: February 2021 to December 2022
• Acceptance Chile: January to February 2023
• Commissioning: February to July 2023
PLATOSpec will be an important new facility for TLS. For modest costs TLS scientists will
now have guaranteed access to a telescope and high resolution spectrograph in the
southern hemisphere. Furthermore, since the telescope will be controlled remotely will
make it practical facility for the teaching and training of students.
7.7 The LOFAR Two-Metre Sky Survey
The LOFAR Two-metre Sky Survey (LoTSS) is rapidly collecting data sets to map the
northern hemisphere with unprecedented sensitivity and resolution. LoTSS is an
outstanding astronomical radio sky survey, since 1) it will cover half of the entire sky, 2) is
very sensitive, 3) provides a very high resolution and 4) is carried out in the poorly
explored low frequency regime. The survey will enable transformational science in
important astrophysical areas including the formation and evolution of black holes, the
evolution of galaxies and of the large-scale structure in the Universe.
LoTSS will comprise 3,168 data sets with an –already compressed– raw data size of 16
terabytes each, resulting in about 50 petabytes to be stored for the entire survey. About
half of the data are stored in the LOFAR Long Term Archive (LTA) at the
Forschungszentrum Jülich (FZJ). The TLS contributes to the survey by supporting the
Long Term proposal to obtain the large amount of observing time. The amount of LoTSS
data stored in LTA at FZJ is too large to be transferred through the internet for
processing. TLS also contributes to the survey by leading a computing project (CHTB00)
to carry out the necessary processing on the supercomputer JUWELS at FZJ. Together
with the partners from FZJ and LoTSS we also realize the necessary data handling from
the archive to further processing on dedicated hardware.
Since LoTSS has by an order of magnitude better sensitivity and resolution compared to
previous surveys, it revolutionizes our view of extended emission, e.g., of Active Galactic
Nuclei and of merging galaxy clusters. TLS scientists Dr. M. Hoeft and Dr. A. Drabent
primarily participate in the Galaxy Clusters Working Group of LoTSS. Figure 22 shows
the spectacular radio galaxy 3C 264 and a radio relic to the north east which is possibly
related to the infalling galaxy UGC 6697. The study of this cluster is part of the master
project of S. Oberhauser. Moreover, the TLS collaborates with AIP scientists to cross-
correlate source populations in radio and X-ray to identify Inverse Compton ghosts which
are supposed to be a dominant X-ray source population at high redshifts.
The LoTSS source catalogue will comprise an enormous number of sources. An optical
spectroscopic follow up survey is currently under way (WEAVE) to classify the sources
and determine the redshift. For radio galaxies the optical counter part is often difficult to
identify and artificial intelligence algorithms still cannot distinguish well between radio
galaxies. Thus a citizen science project (LOFAR Galaxy Zoo) will be released mid of
February to help astronomers identify radio galaxies.
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