Form 8

Research Result Report
ICRR Inter-University Research Program 2022
Research Subject: Engineering runs of the first Large Size Telescope of CTA andconstruction of LST2-4 in La Palma Canary Islands, Spain
Principal Investigator:

MAZIN, DANIEL

Participating Researchers:
Masahiro Teshima, Daniela Hadasch, Koji Noda, Juan Cortina, Carlos Diaz, ThomasSchweizer, Holger Wetteskind, Carlos Delgado, Riccardo Rando, Takayuki Saito,
Armand Fiasson, Ievgen Vovk, Marcel Strzys

Summary of Research Result：
The purpose of the project is to commission thefirst Large Size Telescope (LST, see Figure 1) ofthe CTA project in La Palma, Canary Islands,Spain. In FY2022 the goal was to validate thesensitivity of the instrument and to increase
the availability of the telescope to the one
Figure 1: Completed LST1 in La
Palma in October 2018.

required by CTA to be above 95% over a longer
period of time.
Statusofthecommissioning:

Severalcommissioning goals have been achieved in FY2022. In particular, automatic follow
up of Gamma Ray Bursts, without intervention of operators, has been validated andis now routinely used. Moreover, anautomatic

follow

upofMAGICtelescopes has been implemented and is
successfully used, which increased theduty cycle of the joint MAGIC-LST
observations by some 25% because
there is no longer a need of manual
coordination between the MAGIC andLST shift crews. LST1 is operated from
Figure 2: Achieved flux sensitivity of LST-1

remote and locally onsite thanks to theperiodic IT and security upgradesForm 8

performed in FY2022. A new
weather station has been installedin LST1, providing vital safety
informationontheweather

conditions during operation. TheLST1

performance

hasbeenstudied in great detail and aFigure 3: Energy spectrum of Crab Nebula with LST1

publication

inAstrophysicalJournal is under a review process,see some results in Fig 2. and Fig. 3. In the meanwhile, thanks to a focused effort bya task force on the camera control software, the telescope availability increased from
75% to 85%. This is still below the required 95% from CTA, but the team is convinced
we are on the right track to achieve this requirement in FY2023.
LST2-4 construction status.

Theconstruction license for the LST2-4
erection was granted by the local
authorities of La Palma in September
2022. Soon after, in November 2022 thecivil works started. The progress of thecivil works is good and according to ourFigure
ofof
construction
works
Figure4:4:LST4
LST4status
statusconstruction
works

schedule, and we expect that theyfinish in August 2023. So far, the area

has been cleared, the excavation works
completed, the central area compacted andthe inner piece of the central pin installed, inall three telescopes, see Fig. 4 and Fig. 5.
Scientific return. LST1 is taking regular dataon scientific targets together with the MAGIC
telescopes and the live-time of scientific runs
with LST1 superseded 1800h since January
2020. The results of this observations start tobecome public. Observations of LHAASO
J2108+5157 are in A&A in press, while twomore publications have been submitted for aFigure 5: cage of the central pin of LST-2

No. 2022ｄ-E-004

journal referee process.