Young scientist from CASSACA pens review on accreting supermassive black holes in Nature Astronomy

Dr. Claudio Ricci, a CAS-CONICYT Postdoctoral Fellow in astronomy, recently authored a review paper in 《Nature Astronomy》 with Cristina Ramos Almeida of IAC Tenerife, in which they summarized the most important developments of the past ten years in the fields of accreting black holes and circum-nuclear materials, as revealed by observations in the X-ray and infrared bands.

All massive galaxies host supermassive black holes (SMBH) at their centers, and these objects are often found to be hidden behind large amounts of gas and dust. This circum-nuclear material is what eventually accretes onto the black hole, allowing it to grow, and its structure and evolution have been the subject of intense study in the past decade. Chinese Academy of Sciences South America Center for Astronomy (CASSACA)’s postdoctoral fellow Claudio Ricci and Dr. Cristina Ramos Almeida (IAC Tenerife) were recently invited to write a review for《Nature Astronomy》 on this subject, with the idea of combining results obtained from X-ray and infrared studies of the close environments of supermassive black holes. These two energy bands are highly complementary: while X-rays are produced very close to the supermassive black hole and allow the study of radiation absorbed and reflected, infrared radiation is directly produced by the dust around the black hole.

A black hole is a place in space where gravity pulls so much that even light cannot get out, and therefore itself is “black” in any bands. The theory of general relativity predicts that a sufficiently large and compact mass can deform space time and give birth to a black hole. Black holes of stellar masses are expected to form when very massive stars collapse at the end of their life cycle. After a black hole is formed, it can continue to grow by absorbing mass from its surroundings. By absorbing other stars and merging with other black holes, supermassive black holes of millions of solar masses may form. The first widely-accepted black hole is Cygnus X-1 discovered in 1964, and it weighs about 15 solar masses (Figure 1). The well-known radio source named Sagittarius A*, sitting at the core of our own Milky Way galaxy, contains a supermassive black hole of about 4.3 million solar masses.

Despite its invisible interior, the presence of a black hole can be inferred through its interactions with matter. Circum-nuclear materials falls onto a black hole, and forms an AGN (active galactic nucleus), one of the brightest objects in the universe, including an external accretion disk, an X-ray emitting corona, a broad-line region (BLR), a torus and a narrow-line region (NLR) (Figure 2), which have various physical characteristics, and their radiation are widely used to study the black hole and its surroundings.

The review summarizes the most important developments of the past ten years in this field, and particularly in light of the most advanced X-ray and IR facilities. The authors discuss why the circum-nuclear material is anisotropic, clumpy, and connects with the host galaxy via gas inflow/outflows. They also highlight the importance of dust emission from the polar region of the AGN, possibly related to outflows caused by radiation pressure from the accreting supermassive black hole. Future observing facilities will allow a better understanding of the nuclear environment of AGN, and a fuller description on how it links the black hole to its host galaxy. In particular, the upcoming James Webb Space Telescope (JWST) will allow us to probe the structure and evolution of AGN’s polar dust, while high-resolution spectrometers, such as the ones on board XARM and Athena satellites, will shed light on the physical characteristics of the gas and dust.

Dr. Ricci was invited to write this review because of his significant contribution to this field of research, and in particular in the light of his recent studies on the properties of the most heavily obscured accretion events in the Universe, and of the discovery that the merger of two or more galaxies can strongly affect the surroundings of the supermassive black hole, enriching it in gas and dust. Being able to publish review papers in such prestigious scholarly journals is usually an indication of wide acceptance and recognition of the author’s research work.

For young scientists such as Ricci and Almeida, this is an even more remarkable testimonial to their creative contribution to the relevant subject matter.

Figure 1. An artist’s drawing of a black hole named Cygnus X-1. It formed when a large star caved in. This black hole pulls matter from the blue star beside it. Taken from NASA/CXC/M. Weiss.

Figure 2. Sketch of the main AGN structures, seen along the equatorial and polar directions. From the center to host-galaxy scales: SMBH (Super Massive Black Hole), accretion disk and X-ray emitting corona, BLR (Broad-Line Region), torus and NLR (Narrow-Line Region). Different colors indicate different compositions or densities. Taken from Ramos Almeida & Ricci (2017, Nature Astronomy).

For more information about the Nature Astronomy Review, please visit

Call for China-Chile Joint Research project 2015

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.

Project duration will be 1-2 years, with funding level around $75k USD in average. The PI of the proposal must be from either China or Chile, and the subject can be in any area of astronomical research, including observations, instrumental development, and theory.

For more details, please read the attached announcement (pdf).

China-CONICYT Postdoctoral Fellowship 2015

The Chinese Academy of Sciences (CAS) and the Comisión Nacional de Investigación Científica y Tecnológica (CONICYT) of Chile are inviting for applications for post-doctoral fellowships in observational, theoretical, and/or computational astrophysics. The official announcement of this opportunity is made at the CONICYT website ( and duplicated at The duration of the Fellowship is for two to three years, with at least part of it spent at a host institution in Chile.

Preferential considerations will be given to those applicants with proposed research activities involving collaborations between the Chinese and Chilean astronomy communities. Potential applicants should check out the two web sites above for more up-to-date information on this opportunity and possible deadline extensions, and are encouraged to contact prospective sponsors accordingly before applying. A catalogue of  research projected proposed can be found at

Applications must include the CV, a research statement, a support letter from the Host institution in Chile signed by the Department Director and faculty sponsor, a copy or certificate of degree, and two recommendation letters. The applications will be received at and all the documents except recommendation letters should furthermore be sent  by email in PDF format to and before the deadline August 31st. Further inquires about this fellowship opportunity can be addressed to Dr. Jiasheng Huang, Chief Scientist of CASSACA (the CAS South America Center for Astronomy) at

The Fourth Chile-China Astronomy Science Workshop held successfully in Guangzhou, Dec. 7-10, 2014

In order to promote the communication and collaboration between astronomy communities of China and Chile, sponsored by Chinese Academy of Sciences (CAS), National Natural Science Foundation of China (NSFC), National Astronomical Observatories, CAS (NAOC), the “Fourth China-Chile Astronomy Workshop” was successfully held in Sun Yat-Sen University (SYSU), Guangzhou, on Dec. 7-10, 2014. The meeting was organized by the CAS South American Center for Astronomy (CASSACA), also known as China-Chile Joint Center for Astronomy (CCJCA), with the help of the School of Astronomy and Space Sciences of SYSU.

CASSACA is one of the overseas projects initiated by CAS to develop cooperation in science and technology with foreign countries. In February 2013, CASSACA was inaugurated at NAOC, and its Santiago office was inaugurated in October 2013 at University of Chile. The Center serves as a platform for collaboration in astronomical research and related technologies between China and South America countries. The Center helps to build international scientific teams and joint programs engaging in frontier astronomy research. The China-Chile Astronomy Workshop is a major platform to strengthen communications in astronomical research between the two countries, and has been held alternately in Chile and China. It has been proven to be successful in the past meetings of the series, prompting knowledge and information exchange between astronomers, and initiating collaborative projects and joint programs.

Around 100 participants attended this Workshop, including experts, young scientists and students. Professor Xiping Zhu, vice president of SYSU offered his welcome as the host; Jinghua Cao, Deputy Director of the Bureau of International Cooperation, CAS and Guoxuan Dong, Deputy Director of Mathematics and Physics Department, NSFC, both addressed the meeting; Professor Rojo Patricio, Chairman of Astronomical Society of Chile (SOCHIAS) and other Chilean astronomers expressed high expectations for the Chile-China cooperation, and gave a lot of suggestions and comments;Dr. Zhong Wang, Director of CASSACA, and Dr. Jiasheng Huang, its Chief Scientist introduced the current status and future prospects of the Center. At this Workshop, directors or their representatives of nearly all major astronomical observatories/departments of China and Chile summarized the major research areas and current activities of their institutions, and also gave detailed talks on some recent research highlights. During the four-day workshop, astronomers from both countries communicated cordially and comprehensively, reviewing the existing ties and finding opportunities for future collaboration. The bilateral workshop is recognized as an important catalyst for Chile-China astronomy communications, and a useful model for CAS to advance international cooperation widely.

The website for this bilateral workshop is at


Workshop group photo


Jinghua CAO, Deputy Director of the Bureau of International Cooperation, CAS, addresses the meeting


A glance at the workshop


Progress of CASSACA, talk by Dr. Zhong Wang, director of CASSACA

The 4th Chile-China Astronomy Science workshop

In order to promote the communication and collaboration between astronomy communities of Chile and Chile, the 4th China-Chile Astronomy workshop will be held in Guangzhou, on Dec 7 – 10, 2014.

Guangzhou, the capital of the Guangdong Province,  is a beautiful and well developed city in China. It is China’s 3rd largest city, with a population of about 13 million, and Known as “The Goat City”. Guangzhou is also a trourist city, and have warm and comfortable weather in November.

CASSACA sincerely invite interested participants to join in the workshop and appreciate your contribution of talks. Please fill in the online early registration before September 29th, 2014, and submit your talk title and abstract before September 25th, 2014  if you wish to be considered for travel support, or before 10th October  if not. Read more at