Meeting of the CTAO Science Consortium (2025).
The CTAO Science Consortium held a meeting
in May 12-16 in Garching, Germany. The meeting provided
a good opportunity to updated the science prospects for CTAO and to review the status of the construction of CTAO,
which has now formally started with the establishment of the CTAO ERIC (European Research Infrastructure Consortium).
At the meeting, Rene Ong was honored for serving as CTAO Co-Spokesperson for ten years (2014-2024)
GAPS Experiment Integrated at NASA Facilities in Preparation for Launch (2024-25).
GAPS is a novel balloon experiment designed to search for primary antimatter in the cosmic rays
with unprecedented sensitivity. The experiment is funded by NASA in the US, by INFN and ASI in Italy,
and by JAXA in Japan. During 2024, GAPS was shipped to NASA's Columbia Scientific Balloon Facility (CSBF, Palestine, TX)
and integrated and tested there. It was then dismantled and made the long trip to Antarctica and was
re-integrated at the NASA facilities at the
McMurdo Station
of the National Science Foundation. The current schedule
calls for final testing and flight in late 2025.
CTAO Paper on Prospects for a Survey of the Galactic Plane (2024).
The Cherenkov Telescope Array Observatory (CTAO, formally CTA) will carry out a number of Key Science Projects (KSPs),
as outlined in the "Science with CTA" book (see below). The intellectual effort for these KSPs will be organized
by the CTAO Science Consortium. A very important KSP is the planned survey of the Galactic plane.
A detailed paper
describes the prospects for this survey, including the expected discovery at very
high energies of many more pulsar wind nebulae, supernova remnants and compact binary systems.
VERITAS Paper on the High-Energy Processes in the Galactic Center Region (2021).
A paper summarizing the
latest VERITAS results on the VHE gamma-ray emission from the region of the Galactic Center was published.
In addition to a strong detection of the gamma-ray source associated with Sgr A*, VERITAS identified
a diffuse component of gamma-ray emission along the Galactic Center ridge. This component has an energy
spectrum with a hard spectral index, extending up to 40 TeV, providing evidence for a PeVatron
accelerator in the Galactic Center region. This work was carried out by UCLA graduate students
Matthew Buchovecky and Jamie Ryan.
Science with CTA Book Published (2019).
The book Science with the Cherenkov Telescope Array has been published
by World Scientific; the book can be found here .
Second Workshop on Antideuterons in the Cosmic Rays at UCLA.
Antideuterons have never been detected in the cosmic rays, but their
presence could have major implications for new physics, including
modiels of dark matter and primordial black holes.
Rene Ong, Philip von Doetinchem (U. Hawaii), Kerstin Perez (MIT), and Mirko Boezio (INFN-Trieste)
organized the second workshop at UCLA in March 2019
to explore the science of antideuterons, both from the
theoretical and experimental perspective.
The workshop was entitled
Antideuteron 2019. The review article summarizing
the meeting can be found here.
The Science with CTA document released.
The exciting science program to be carried out by CTA
has been put forward in detail in a 200-page document
Science with the Cherenkov Telescope Array.
This science program was developed over a period of more than five years
by hundreds of scientists in the CTA Consortium. The
first version of the document
was uploaded to the arXiv archive by Rene Ong on 23 September 2017; an revised version was uploaded on January 22, 2018.
For more details, see the
Press Release on the main CTA web site.
GAPS balloon experiment approved by NASA .
In early 2017, NASA approved funding for the GAPS project to enter
the construction phase of the experiment. With funding also available
in Japan and Italy, the GAPS team is now working towards the final design
and construction of the GAPS science payload. The integration of the payload
is scheduled for late 2020 with a first possible science flight during
the 2021-2022 Antarctic season. See the
GAPS website for more details.
2015-2016: Progress on the Cherenkov Telescope Array (CTA).
Consisting of two large arrays of atmospheric Cherenkov telescopes, CTA
will explore the very high energy (VHE) universe with unprecedented sensitivity.
During the last year, the design and development of the baseline
observatory made great progress. For an overview of the science of CTA and its
current status, see a recent
article by Liz Kruesi for Symmetry magazine. An
article by Edwin Cartlidge for Science magazine discusses the recent selection
of the two proposed locations for the CTA sites.
Rene Ong elected Co-Spokesperson of the Cherenkov Telescope Array (CTA) Consortium.
In September 2014, at a CTA meeting in Catania, Italy, Rene Ong was elected Co-Spokesperson
of the CTA Consortium. Consisting of over 1,500 scientists from 150 institutions in 25 countries,
the CTA Consortium
was formed to design and help construct CTA and to carry out scientific
investigations with CTA to explore the VHE universe in the decade of 2020 to 2030.
More details on CTA and its science goals can be found at the general
CTA public website.
Update on the Cherenkov Telescope Array.
The year 2015 was an important one for
CTA with a successful Critical Design Review (CDR) and the selection of the observatory
sites.
An article by Kelen Tuttle in Symmetry magazine
provides a good summary
of recent activities and the site selection process.
1st Workshop on Antideuterons in the Cosmic Rays.
Rene Ong and Philip von Doetinchem (U. Hawaii) organized the 1st workshop dedicated
to the science of cosmic ray antideuterons.
The workshop was entitled
Antideuteron 2014 and was held at UCLA in June 2014.
Update on the Cherenkov Telescope Array.
CTA is a major ground-based gamma-ray telescope project that is under development.
CTA plans to construct two large arrays of atmospheric Cherenkov
telescopes, one to be installed in the northern hemisphere and one in the southern
hemisphere. UCLA is actively working on the site characterization and evaluation
studies and is helping to propose two possible sites for the northern array
of CTA in Arizona, USA. One proposed site is located 70 km east of Flagstaff, AZ,
near Meteor Crater; the other proposed site is located 150 km west of Flagstaff, AZ,
on Yavapai Ranch. See the
recent article by Elizabeth Gibney in Scientific American that summarizes
the present situation. There is also an earlier article on CTA site selection in
Science magazine by Nuno Dominguez and a nice article describing the scientific motivation for CTA in
Nature magazine by Eugenie Reich.
Successful flight of the prototype GAPS (pGAPS) balloon experiment (2012).
GAPS is a proposed experiment to search for anti-deuterons in the cosmic rays.
These particles have never been detected astrophysically but would provide
strong evidence for the annihilation of WIMP dark matter.
The GAPS team, consisting of ~20 scientists in the US and Japan,
designed and constructed a prototype instrument (pGAPS) to verify many of the
key design elements of GAPS. After integration in the US, pGAPS was launched
in June 2012
by the Japanese space agency (JAXA) from their balloon facility in eastern
Hokkaido, Japan. A very successful, six-hour flight followed, as
documented on the GAPS website
and in a paper written by UCLA postdoc S. Isaac Mognet.
The team is now proposing to build the full GAPS instrument for flight from
NASA's balloon launch facility at the McMurdo Station in Antarctica.
VERITAS detects gamma rays above 100 GeV from the Crab Pulsar (2011).
The Crab, the remnant from a supernova explosion seen on Earth in 1054,
is a famous object in astronomy. Ground-based observatories have detected very high
energy (VHE) gamma-ray emission from the Crab for more than two decades, but these
(unpulsed) detections were from the Crab Nebula. It has always been a dream to
detect VHE emission from the pulsar itself. Based on more than 100 hours of data,
VERITAS made the first detection of the Crab Pulsar above 100 GeV.
The result, reported in a
paper published in Science,
indicates a completely new, and unexpected, component of radiation and does not
fit within standard pulsar models. The VERITAS detection was highlighted by many
science blogs and was the subject of
a nice article written by Kim DeRose of the UCLA press office.
VERITAS discovers VHE gamma rays from the Tycho supernova remnant . The Tycho
supernova remnant (SNR) derives from the Type 1a supernova seen on Earth in 1572.
As one of only a handful of historical supernovae, Tycho is a very important source in the
history of astronomy. The Tycho SNR has been deeply studied and is one of the best
understood remnants. Thus, it was always a prime target for observation by northern hemisphere
atmospheric Cherenkov telescopes, such as VERITAS. The VERITAS detection came from deep
observations made between 2008 and 2010 and are reported in a
paper published in
Astrophyical Journal Letters. Following the discovery by VERITAS, Tycho was detected at
GeV energies by Fermi. Of key importance is that the resulting gamma-ray
spectrum from the lowest energies detected by Fermi to the highest energies detected by VERITAS
strongly support a cosmic ray (proton) origin for the observed gamma-ray emission.
Fermi detects gamma rays from the binary source Cygnus X-3. Cygnus X-3 is a rather
famous X-ray object that was "discovered" as a soure of TeV and even PeV gamma rays in the 1970's
and the 1980's. In fact, these discoveries accelerated the growth of the field of VHE
astronomy. In the 1990's and 2000's, Cygnus X-3 was not firmly detected by any
gamma-ray telescope, leading to speculation that the original results were statistical
fluctations. Now, recent observations by the Large Area Telescope (LAT) of the
Fermi Gamma-ray Space Telescope show a clear detection of Cygnus X-3, where the
gamma-ray signal is correlated with the 4.8 hour orbital period of the binary system.
Contributing to the LAT analysis were two UCLA undergraduates, Nickolas McColl and
Laura Marchand, and this work contributed to a
paper published in
Science.
VERITAS makes the first detection of gamma rays from a starburst galaxy (M82). This discovery provides important clues towards understanding the origins of cosmic rays. Read the journal article in Nature. Popular articles can be found in Astronomy.com and in the CERN Courier.
VERITAS discovers VHE gamma rays from a powerful blazar 1ES 0502+675. This source is one of the most distant objects known to emit TeV gamma rays. Since TeV photons are expected to be absorbed by intergalactic radiation fields, this discovery is surprising because it implies that the Universe is more transparent at these energies than expected. Indeed, there are speculations that some sort of new physics may be involved. The discovery was announced in an Astronomical Telegram.
Rachel Courtland wrote a nice article in the New Scientist on the possible existence of axion-like particles to explain the observations.