Written by Jennifer Chu, MIT News Office
Scattered across our Milky Way galaxy are tens of millions of black holes —immensely strong gravitational wells of spacetime, from which infalling matter, and even light, can never escape. Black holes are dark by definition, except on the rare occasions when they feed. As a black hole pulls in gas and dust from an orbiting star, it can give off spectacular bursts of X-ray light that bounce and echo off the inspiraling gas, briefly illuminating a black hole’s extreme surroundings.
Now MIT astronomers are looking for flashes and echoes from nearby black hole X-ray binaries — systems with a star orbiting, and occasionally being eaten away by, a black hole. They are analyzing the echoes from such systems to reconstruct a black hole’s immediate, extreme vicinity.
In a study appearing today in the Astrophysical Journal, the researchers report using a new automated search tool, which they’ve coined the “Reverberation Machine,” to comb through satellite data for signs of black hole echoes. In their search, they have discovered eight new echoing black hole binaries in our galaxy. Previously, only two such systems in the Milky Way were known to emit X-ray echoes.
In comparing the echoes across systems, the team has pieced together a general picture of how a black hole evolves during an outburst. Across all systems, they observed that a black hole first undergoes a “hard” state, whipping up a corona of high-energy photons along with a jet of relativistic particles that is launched away at close to the speed of light. The researchers discovered that at a certain point, the black hole gives off one final, high-energy flash, before transitioning to a “soft,” low-energy state.
This final flash may be a sign that a black hole’s corona, the region of high-energy plasma just outside a black hole’s boundary, briefly expands, ejecting a final burst of high-energy particles before disappearing entirely. These findings could help to explain how larger, supermassive black holes at the center of a galaxy can eject particles across vastly cosmic scales to shape a galaxy’s formation.
“The role of black holes in galaxy evolution is an outstanding question in modern astrophysics,” says Erin Kara, assistant professor of physics at MIT. “Interestingly, these black hole binaries appear to be ‘mini’ supermassive black holes, and so by understanding the outbursts in these small, nearby systems, we can understand how similar outbursts in supermassive black holes affect the galaxies in which they reside.”
The study’s first author is MIT graduate student Jingyi Wang; other co-authors include Matteo Lucchini and Ron Remillard at MIT, along with collaborators from Caltech and other institutions.
Kara and her colleagues are using X-ray echoes to map a black hole’s vicinity, much the way that bats use sound echoes to navigate their surroundings. When a bat emits a call, the sound can bounce off an obstacle and return to the bat as an echo. The time it takes for the echo to return is relative to the distance between the bat and the obstacle, giving the animal a mental map of its surroundings.
In similar fashion, the MIT team is looking to map the immediate vicinity of a black hole using X-ray echoes. The echoes represent time delays between two types of X-ray light: light emitted directly from the corona, and light from the corona that bounces off the accretion disk of inspiraling gas and dust.
The time when a telescope receives light from the corona, compared to when it receives the X-ray echoes, gives an estimate of the distance between the corona and the accretion disk. Watching how these time delays change can reveal how a black hole’s corona and disk evolve as the black hole consumes stellar material.
In their new study, the team developed search algorithm to comb through data taken by NASA’s Neutron star Interior Composition Explorer, or NICER, a high-time-resolution X-ray telescope aboard the International Space Station. The algorithm picked out 26 black hole X-ray binary systems that were previously known to emit X-ray outbursts. Of these 26, the team found that 10 systems were close and bright enough that they could discern X-ray echoes amid the outbursts. Eight of the 10 were previously not known to emit echoes.
“We see new signatures of reverberation in eight sources,” Wang says. “The black holes range in mass from five to 15 times the mass of the sun, and they’re all in binary systems with normal, low-mass, sun-like stars.”
As a side project, Kara is working with MIT education and music scholars, Kyle Keane and Ian Condry, to convert the emission from a typical X-ray echo into audible sound waves. Take a listen to the sound of a black hole echo here: https://www.youtube.com/watch?v=iIeIag2Ji8k.
The researchers then ran the algorithm on the 10 black hole binaries and divided the data into groups with similar “spectral timing features,” that is, similar delays between high-energy X-rays and reprocessed echoes. This helped to quickly track the change in X-ray echoes at every stage during a black hole’s outburst.
The team identified a common evolution across all systems. In the initial “hard” state, in which a corona and jet of high-energy particles dominates the black hole’s energy, they detected time lags that were short and fast, on the order of milliseconds. This hard state lasts for several weeks. Then, a transition occurs over several days, in which the corona and jet sputter and die out, and a soft state takes over, dominated by lower-energy X-rays from the black hole’s accretion disk.
During this hard-to-soft transition state, the team discovered that time lags grew momentarily longer in all 10 systems, implying the distance between the corona and disk also grew larger. One explanation is that the corona may briefly expand outward and upward, in a last high-energy burst before the black hole finishes the bulk of its stellar meal and goes quiet.
“We’re at the beginnings of being able to use these light echoes to reconstruct the environments closest to the black hole,” Kara says. “Now we’ve shown these echoes are commonly observed, and we’re able to probe connections between a black hole’s disk, jet, and corona in a new way.”
This research was supported, in part, by NASA.
NMIMS SBM Offers MBA (Part-Time) Program for Working Executives
The program focuses on providing a holistic education to enhance their employability
Start your professional learning journey now with the best-in-class MBA (Part-Time) program with the most sought-after prestigious NMIMS, School of Business Management, featured in the top 100 global B-schools as per Financial Times MiM 2022 ranking. A highly respected business school in India with a legacy of 41 years and a prestigious faculty announces admissions open for their MBA (Part-Time) program at their Mumbai campus.
This program offers an opportunity for working executives to acquire a high-end compact management qualification through rigorous and qualitative in-class learning and practical exposure to industry expertise. The program focuses on providing a holistic education to enhance their employability, exposing working executives to contemporary trends and practices in management. It also provides excellent academic resources coupled with industry best practices to boost the managerial competence of executives.
NMIMS SBM MBA (Part-Time) is accredited by Advance Collegiate Schools of Business (AACSB) for working executives who want to enhance their skills and advance their careers. NMIMS has world-class pedagogy to provide students with a comprehensive and engaging learning experience. NMIMS SBM has a team of experts with extensive experience in the business world. The program structure is upto 40% hybrid and 60% in the classroom, whereas Bloomberg Certification Program will help students use financial analysis tools more efficiently.
“The program is specifically meant for executives who have spent quality time in the industry and have adequate exposure to managerial roles and responsibilities. The two-year MBA (Part-Time) program will offer an opportunity for participants to hone their managerial skills and enable them to contribute better to their decision-making. It has been designed to empower students with a well-planned schedule that allows for a balance between study and work,” said Dr. Prashant Mishra, Dean School of Business Management.
Dr. Pradeep Pai, Program Chairperson, MBA (Part-Time), School of Business Management, said, “NMIMS SBM is proud to offer this innovative program to working professionals who wish to take the next step in their careers. We believe that this program will be a preferred executive education program for working professionals seeking to upgrade their qualifications by acquiring a widely acclaimed MBA degree.”
The MBA (Part-Time) program goes beyond traditional education by providing learners value-added workshops and industry connections. Our curriculum is regularly updated to ensure students receive the most current knowledge. The program helps them gain a practical and theoretical understanding of the industry and creates a network of professionals for them as they progress.
- 50% in Graduation from a recognized University in any discipline. (Distance/Part time/Full time)
- Minimum 3 years of work experience in an executive or supervisory capacity or self-employed after graduation & up to the date of written test/personal interview.
- The work experience should be full-time experience and should NOT include internships, projects, training periods, trainee (management, engineering), etc.
Written Test conducted for MBA (Part-Time) by NMIMS OR Candidates with GMAT score of 600 and above (GMAT score of last 5 years up to the closure of registrations will be considered) OR Candidates with a score of 200 and above in NMAT by GMAC examinations for 2020 admission AND Personal Interview
eSecForte visited Northeast to strengthen Industry-Academia Interface for Achieving Effective Cybersecurity Prospects
The team also visited the Indian Institute of Information Technology (IIIT), Manipur and interacted with students on the topic of Digital Forensics Challenges and career options
In an effort to create a holistic ecosystem for cybersecurity in the country, the team from eSecForte led by Lt Col (Dr.) Santosh Khadsare (Retd), VP Digital Forensics & Incident Response visited the National Institute of Electronics and Information Technology (NEILT), Kohima and held discussions with the director of the institute, L. Lanuwabang. The deliberations were focused on enlarging the gambit of cybersecurity especially digital forensics in the country and how eSecForte and NEILT can come together to contribute effectively in this regard.
The team also visited the Indian Institute of Information Technology (IIIT), Manipur and interacted with students on the topic of Digital Forensics Challenges and career options. The discussion entailed how the use of digital forensics can prove instrumental in bringing the perpetrators of cybercrimes to the book. The various challenges related to the implementation of tools and methodologies of digital forensics were also part of the very constructive dialogue that was held between our team and enthusiastic students.
The team lead had a very fruitful discussion with Dr Krishnan Bhaskar, Director, IIIT, Imphal and discussed how the Industry-Academia interface can do wonders in the field of cybersecurity and digital forensics. Specifically, detailed deliberations were held on devising exchange mechanisms and collaborative opportunities so that industry and academics can come together and lead to the creation of a self-sustainable ecosystem in the field of cybersecurity. Such development will ensure that cases related to the cybercrimes are dealt swiftly and lead to desired outcomes in terms of ensuring justice and well-being for all participating stakeholders.
In the next leg of the reaching out journey, eSecForte’s team paid a visit to the National Forensic Science University (NFSU), Imphal campus and exchanged ideas with the campus coordinator on the latest trends and developments in the field of digital forensics. Apprising the importance of digital forensics to investigating officers, Lt Col (Dr.) Santosh Khadsare (Retd), VP DFIR interacted with more than 400 trainees of the North Eastern Police Academy (NEPA), Shillong. These aspirants were thoroughly apprised of the importance of digital forensics and its utility in cracking cases related to cyberfrauds, cyberbullying, and other allied crimes associated with cyberspace. Case studies were discussed on how to handle digital evidence at the crime scenes with utmost care so that trace evidence won’t get lost in the logistical procedures and processes. The team showcased flagship products of eSecForte, Digital Forensic workstations and Faraday bags and informed them of the utility of these offerings built under India’s ambitious MAKE IN INDIA (MII) project.
Roots Collegium signs World Chess Champion Koneru Humpy as Brand Ambassador
Chairman, Sri. B.P.Padala announces Koneru Humpy as the Brand Ambassador of Roots Collegium educational institutions
- Humpy will be the face of its upcoming brand-related undertakings
Celebrating its 30 years’ legacy in imparting holistic education, Roots Collegium, a well-known educational institution in Hyderabad has today announced World Chess Champion Koneru Humpy as its Brand Ambassador. The appointment of Ms. Koneru Humpy is set to boost the brand image of Roots Collegium amplifying the institution’s philosophy in making its students achieve global exposure.
With the signing up of world chess champion Koneru Humpy as its Brand Ambassador, Roots Collegium will be exploring untapped areas of new-age innovations and add them to its list of achievements in the last 30 years. The fast expanding Roots Collegium, started in 1991, offers intermediate courses and almost all the streams of Bachelor’s degrees. Roots collegium is providing a wide range of courses like BBA, BBA (Business Analytics, B.Com (General, computers, sales), BA (Mass Communication, Psychology, and modern languages), and B.Sc. (Data Analysis). The college provides a variety of courses in design, film and media, visual arts, hotel management, culinary arts, and also many other certificate courses.
Reacting to her appointment, Koneru Humpy said “It is my pleasure to be the brand ambassador of Roots Collegium. I thank Sri. BP Padala gaaru for the honour. Roots Collegium as an institution has been offering the best educational facilities for its students for the last 30 years. Roots and I share a similar journey as we both have started our journey’s 30 years back. We both have same passion, integrity and ethics. That’s the special part about Roots Collegium, to which I instantly related to. And now we are ready to travel together. As an ambassador, I look forward to contributing my committed services to the college and helping them grow in stature. I will take part in each and every event of the college and would like to share my thoughts and way-forward ideas in all its initiatives. Once again I want to thank all the staff and management for choosing me as a brand ambassador.”
Koneru Humpy is the FIDE Women’s rapid chess champion of 2019. She became the youngest woman to achieve the title of a Grandmaster back in 2002 at the age of 15. Her association will be an added feather to the cap of Roots Collegium’s growing achievements and a historic moment in its journey.
The Chairman of Roots Collegium, Sri. B P Padala said “It’s our honour to have such a young and dynamic chess champion, Koneru Humpy as our brand ambassador. I wish the students of Roots Collegium will be motivated by such an inspiring champion who has come across a lot to be in this position today. I have no doubt that with her determination and strong belief, she become a world champion. I hope every student will inculcate the habit of not giving up and fighting for what they want, from her. She will be a role model for each and every student of our institution. I thank Koneru Humpy for accepting this position and people like her will definitely help bring change in society.”
The students of Roots Collegium from different places in Hyderabad city are excited and look forward to listen to the life-changing stories from Koneru Humpy in the future.
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