Based on the principles established in a 2013 Memorandum of Understanding (MoU) between the Chinese Academy of Sciences (CAS) and the National Commission of Scientific and Technological Research of the Republic of Chile (CONICYT), and the more specific guidelines described in a recent (2015) Agreement between the National Astronomical Observatories of China (NAOC), the Chinese Astronomical Society, the Chilean Astronomical Society (SOCHIAS) and CONICYT (pdf), we are now inviting research proposals that involve China-Chile collaboration in astronomical research, to promote astronomical research collaborations between China and Chile, to advance astronomy in both countries.
These funds are for research projects based on a collaboration between astronomers from China and Chile, and the subject can be in areas such as astronomical research, observations, instrumental development, theory, etc.
The duration of each project should be two years at maximum, and can request up to 75,000 USD/year. We are aiming to support 3 or 4 projects in this call.
The deadline for applications is now extended to May,31st 2022. Inquiries can be sent to Dr. Jiasheng Huang (Chief Scientist of CASSACA; jhuang#@#nao.cas.cn), or Dr. Lei Zhu (Deputy Director of CASSACA; lzhu#@#nao.cas.cn).
For more details, please read the attached announcement (pdf).
The role of active galactic nuclei (AGNs) during galaxy interactions and how they influence the star formation in the system are still under debate. Recently, a research team led by the Chinese Academy of Sciences South America Center for Astronomy (CASSACA) used the integral field unit (IFU) data to study the star-formation distributions of a paired active galactic nuclei (AGN) sample. They found that AGNs are likely follow an inside-out quenching and the merger impact on the star formation in AGNs is less prominent than in star-forming galaxies (SFGs).
Upper panel: An example of AGN identification using IFU data. Lower left: Similar distributions of paired AGNs and isolated AGNs in the SFR-Mass diagram. Lower right: Interaction show different impact on the resolved properties of AGNs and SFGs.
This pair sample of 1156 IFU-covered galaxies were selected by the velocity offset, projected separation, and morphology from SDSS IV-MaNGA survey, and is further classified into four cases along the merger sequence based on morphological signatures. A total of 61 (5.5%) AGNs in pairs were identified based on the emission-line diagnostics. No evolution of the AGN fraction was found, either along the merger sequence or compared to isolated galaxies (5.0%). There was a higher fraction of passive galaxies in galaxy pairs, especially in the pre-merging cases, which was related to a denser environment. The isolated AGN and AGNs in pairs showed similar distributions in their global stellar mass, star-formation rate (SFR), and central [O iii] surface brightness. AGNs in pairs showed radial profiles of increasing specific SFR and declining Dn4000 from center to outskirts, and no significant difference from the isolated AGNs. This was clearly different from SFGs in this pair sample, which showed enhanced central star formation, as reported before. AGNs in pairs had lower Balmer decrements at outer regions, possibly indicating less dust attenuation.
The research paper is recently published in The Astrophysical Journal (https://doi.org/10.3847/1538-4357/ac2901). CASSACA student Gaoxiang Jin and Prof. Y. Sophia Dai are the first author and the corresponding author, respectively.
On October 20, 2021, the Joint Council Meeting of the Chinese Academy of Sciences South America Center for Astronomy (CASSACA) and the China-Brazil Joint Laboratory for Space Weather of CAS (hereinafter referred to as CBJLSW) was held at the headquarter of National Astronomical Observatories, Chinese Academy of Sciences (NAOC). Prof. Zhang Yaping, Vice President of the Chinese Academy of Sciences and the Chairman of CASSACA & CBJLSW Council, attended the meeting. The representatives of the Council members of both centers attended the meeting as well.
The Council reviewed and approved the annual work reports, funding implementations of the year 2021, as well as the work plans and budget arrangements for the next year of both oversea centers. In the meeting, the Council discussed extensively and put forward suggestions on several issues, including the platform operation, scientific research deployment, resource allocation, and international cooperation in the frontier areas such as astronomy, space science, climate and remote sensing observation.
In his concluding speech, Zhang Yaping fully acknowledged the efforts and achievements made by CASSACA and CBJLSW under the current difficult circumstances of COVID-19 pandemic. He pointed out that new requirements should be placed for the oversea centers in the new stage. “The oversea centers should further refine their work priorities, make full use of the unique advantages of the oversea platform, promote multilateral collaboration, and develop a more open and dynamic system”, said by Zhang Yaping. He also encouraged the scientists to propose major scientific ideas and plans in order to gain more and more influential scientific achievements based on the overseas centers.
CASSACA and CBJLSW were two oversea centers of Chinese Academy of Sciences. They were set up in October 2013 in Chile and in August 2014 in Brazil separately. They have been playing an important role in the international collaborations in the areas of astronomy and space weather between China and South America countries.
The Five-hundred-meter Aperture Spherical Radio Telescope (FAST) is the largest telescope with the highest sensitivity in the world. Extragalactic neutral hydrogen detection is one of important scientific goals of FAST.
Recently, an international research team led by Dr. Cheng Cheng from Chinese Academy of Sciences South America Center for Astronomy (CASSACA), successfully detected the neutral hydrogen line emission from three local galaxies using the FAST 19-beam receiver with only five minutes of exposure. The research paper is recently published in Astronomy & Astrophysics Letter. This is the first publication on FAST observation of extragalactic neutral hydrogen.
Fig. 1. The optical color images of the four galaxies for FAST observation. The red contours are the previous CO observation by ALMA. The white spectra in each panel are the results from FAST.
Neutral hydrogen gas is the most extended baryons in galaxies, while cold gas traced by CO is more concentrated to a galaxy center (red contour in Figure 1). With dynamical measurements of neutral hydrogen and CO, we can estimate the mass distribution of galaxies at different radii. Dynamical masses of these four galaxies estimated from the newly observed the neutral hydrogen line are 10 times higher than the observed baryon masses, indicating contribution of dark matter. On the other hand, dynamical masses estimated using previous CO observations were equivalent to their observed baryon masses. Therefore, the new FAST observation illustrates its ability of studying dark matter in galaxies using the neutral hydrogen 21cm emission line.
The FAST observation of these galaxies was an important part of an international research project, the Valparaíso ALMA Line Emission Survey (VALES), led by Prof. Edo Ibar from Valparaiso University in Chile. The VALES is a project of observing star forming galaxies using first-class international facilities such as SDSS, Herschel space observatory, ALMA, APEX and VLT. This international team has been publishing a series of scientific results.
FAST with the unpreceded sensitivity provides a very unique chance to observe the extra-galactic neutral hydrogen, and therefore has been adding to the list modern astronomical facilities used by this international collaboration. The FAST observation time was awarded in the Share-risk Observing call during the FAST Commissioning Phase. The team will apply for FAST time to further study the neutral hydrogen properties of VALES galaxies.
During
Aug. 12-16, 2019, the 6th “From AGN to starburst: A multi-wavelength synergy”
was successfully held in Guiyang, China. The meeting was organized by National
Astronomy Observatory of CAS (NAOC) and CAS South American Center of Astronomy (CASSACA),
along with the Purple Mountain Observatory (PMO). Over 100 participants from 13
countries and regions attended this meeting. The AGN-starburst meeting series
is a well-known international galaxy physics conference and it keeps focusing
on the most advanced scientific researches and challenges in galaxy formation
and evolution.
Poster
of the meeting
Jiasheng
Huang, SOC & Y.Sophia Dai, chair of SOC/LOC, delivered welcome speeches at
the meeting
Throughout
five days, over fifty reports and 17 poster talks were given by experts, young researchers
and students. The presentations have a wide coverage, from the latest multi-wavelength
observational results across redshifts, to the state-of-art simulation and theoretical
models. Recent ALMA (the Atacama Large Millimeter/submillimeter Array) results
are reported in studies of outflows, gas distribution and star formation
efficiency in both AGNs and starburst galaxies. As for sky surveys in optical
and infrared (IR) wavelength, speakers talked about features in different types
of active galaxies and observational evidences related to “galaxy quenching”. These
reports gave a detailed physical view of the relationship between supermassive blackhole
(SMBH) and galaxy evolution.
(John Silverman, Luis Ho, Ran Wang, Yu Gao, Jeyhan Kartaltepe and
Richard Bower)
Selected photos of experts giving presentations
On
Aug. 15th, participants enjoyed a fantastic visit to the FAST
(Five-hundred-meter Aperture Spherical Telescope) observatory, organized by LOC
members Dr. Qisheng Li and Gaofeng Pan from the FAST observatory. After the introduction
report by Dr. Chao-Wei Tsai, people had heated discussion and expressed
appreciation as well as intentions for future collaborations with FAST.
Participants
at the FAST observatory
Besides
presentations, the meeting also sets aside time every day for free discussions.
Heated debates and discussions were a common scene during these discussion
sessions, over evidences in the connection between AGN and starburst,
challenges in linking theoretical and simulations models to observations, as
well as topics on large-scale galaxy evolution.
George Rieke, David
Rosario, Jiasheng Huang, Yingjie Peng, David Elbaz, Dave Sanders
in discussions
The
last day of the meeting, a special session was dedicated to the many different future
instruments and evolutionary results the new surveys would bring us. Principle
Investigators or experts from FAST, JWST (James Webb Space Telescope), EP (Einstein
Probe), eXTP (enhanced X-ray Timing and Polarimetry Mission) and CSST (Chinese
Space Station Telescope) and other future instruments/surveys introduced the
latest progresses and future plans. Final remarks and demand for future series
were given by the SOC representatives at the end of the meeting. Participants thanked
the organization by the LOC and SOC and looked forward to future international collaborations
and the next meeting.
