
From The MPG Institute for Radio Astronomy [MPG Institut für Radioastronomie](DE)
2.23.23 [Just today in social media.]
Dr. Stefanie Komossa
+49 228 525-386
skomossa@mpifr.de
Dr. Alex Kraus
Station Manager, Effelsberg Radio Observatory
+49 2257 301-101
akraus@mpifr.de
Dr. Norbert Junkes
Press and Public Outreach
+49 228 525-399
njunkes@mpifr.de
The densest and longest radio-to-high-energy view of the binary black hole at the center of the active galaxy OJ 287.
An international research group led by Stefanie Komossa from the MPG Institute for Radio Astronomy in Bonn, Germany, presents important new results on the galaxy OJ 287, based on the most dense and longest radio-to-high-energy observations to date. The scientists were able to test crucial binary model predictions using multiple observing tools including the Effelsberg radio telescope [below] and the Neil Gehrels Swift Observatory.
For the first time, an independent black hole mass determination of the system was performed and the amount of matter in a disk surrounding the black hole could be estimated.
The results show that an exceptionally massive black hole exceeding 10 billion solar masses is no longer needed. Instead, the results favor models with a smaller mass of 100 million solar masses for the primary black hole. Several outstanding mysteries, including the apparent absence of the latest big outburst of OJ 287 (which has now been identified) and the much-discussed emission mechanism during the main outbursts, can be solved this way. Independent results on blazar physics that trace processes near the jet launching region were obtained.
These findings have strong implications for the theoretical modeling of supermassive black hole binary systems and their evolution, for understanding the physics of accretion and jet launching near supermassive black holes, for future pulsar timing vs space-based gravitational wave detection from this system, and a direct spatial resolution of this system with the Event Horizon Telescope or the future SKA
The findings are presented in two papers published in MNRAS Letters [below] and The Astrophysical Journal [below].

Fig. 1: The left panel shows a deep ultraviolet image of OJ 287 and its environment taken with Swift. This is one of the deepest UV images of that part of the sky ever taken, combining 560 single exposures. The brightest source in the field is OJ 287. The black hole region itself cannot be resolved in the UV image. The right panel depicts an artist’s view of the very center of OJ 287, including the accretion disk, the jet, and a second black hole orbiting the primary black hole which has a mass of 100 million solar masses. © S. Komossa et al.; NASA/JPL-Caltech.
Blazars are galaxies that host powerful, long-lived jets of relativistic particles that are launched in the immediate vicinity of their central supermassive black hole.
When two galaxies collide and merge, supermassive binary black holes are formed. These binaries are of great interest because they play a key role in the evolution of galaxies and the growth of supermassive black holes. Furthermore, coalescing binaries are the universe’s loudest sources of gravitational waves. The future ESA cornerstone mission LISA (Laser Interferometer Space Antenna) aims to directly detect such waves in the gravitational wave spectrum. The search for supermassive binary black hole systems is currently in full swing.
OJ 287 is a bright blazar in the direction of the constellation Cancer at a distance of about 5 billion light years. It is one of the best candidates for hosting a compact binary supermassive black hole. Exceptional outbursts of radiation which repeat every 11 to 12 years are OJ 287’s claim to fame. Some of these are so bright, that OJ 287 temporarily becomes the brightest source of its type in the sky. Its repeating outbursts are so remarkable, that several different binary models have been proposed and discussed in the literature to explain them.
As the second black hole in the system orbits the other more massive black hole it imposes semi-periodic signals on the light output of the system by affecting either the jet or the accretion disk of the more massive black hole.
However, until now there has been no direct independent determination of the black hole mass, and none of the models could be critically tested in systematic observing campaigns, because these campaigns lacked a broad-band coverage involving radiation of many different frequencies. For the first time, multiple simultaneous X-ray, UV and radio observations, along with optical and gamma-ray bands were now used. The new findings were made possible by the MOMO project (“Multiwavelength Observations and Modelling of OJ 287”), which is one of the densest and longest-lasting multi-frequency monitoring projects of any blazar involving X-rays, and the densest ever of OJ 287.
“OJ 287 is an excellent laboratory for studying the physical processes that reign in one of the most extreme astrophysical environments: disks and jets of matter in the immediate vicinity of one or two supermassive black holes”, says Stefanie Komossa from the MPG Institute for Radio Astronomy (MPIfR), the first author of the two studies presented here. “Therefore, we initiated the project MOMO. It consists of high-cadence observations of OJ 287 at more than 14 frequencies from the radio to the high energy regime lasting for years, plus dedicated follow-ups at multiple ground- and space-based facilities when the blazar is found at exceptional states.”
“Thousands of data sets have already been taken and analyzed. This makes OJ 287 stand out as one of the best-monitored blazars ever in the UV-X-ray-radio regime”, adds co-author Alex Kraus from the MPIfR. “The Effelsberg radio telescope and the space mission Swift play a central role in the project.”
The Effelsberg telescope provides information at a broad range of radio frequencies, whereas the Neil Gehrels Swift observatory is used to obtain simultaneous UV, optical and X-ray data. High-energy gamma-ray data from the Fermi Gamma-Ray Space Observatory, as well as radio data from the Submillimeter Array (SMA) at Maunakea/Hawai’i, have been added.
The jet dominates the electromagnetic emission of OJ 287 due to its blazar nature. The jet is so bright, that it outshines the radiation from the accretion disk (the radiation of matter falling into the black hole), making it hard to impossible to observe the emission from the accretion disk, as if we were looking directly into a car headlight. However, due to the large number of MOMO observations that densely covered the light output of OJ 287 (a new observation almost every other day with Swift), “deep fades” were discovered. These are times when the jet emission fades away rapidly, allowing the researchers to constrain the emission from the accretion disk. The results show that the disk of matter surrounding the black hole is at least a factor of 10 fainter than previously thought, with a luminosity estimated to be no more than 2 x 10^46 erg/s, corresponding to about 5 trillion times the luminosity of our sun (5 x 10^12 Lʘ).
For the first time the mass of the primary black hole of OJ 287 was derived from the motion of gaseous matter bound to the black hole. The mass amounts to 100 million times the mass of our sun. “This result is very important, as the mass is a key parameter in the models that study the evolution of this binary system: How far are the black holes separated, how quickly will they merge, how strong is their gravitational wave signal?” comments Dirk Grupe of the Northern Kentucky University (USA), a co-author in both studies.
“The new results imply that an exceptionally large mass of the black hole of OJ 287, exceeding 10 billion solar masses, is no longer required; neither is a particularly luminous disk of matter accreting onto the black hole required”, adds Thomas Krichbaum from the MPIfR, a co-author of the ApJ paper. The results rather favor a binary model of more modest mass.
The study also resolves two old puzzles: the apparent absence of the latest of the bright outbursts which OJ 287 is famous for, and the emission mechanism behind the outbursts. The MOMO observations allow for the precise timing of the latest outburst. It did not occur in October 2022, as predicted by the “huge-mass” model, but rather in 2016-2017, which MOMO extensively covered. Furthermore, radio observations with the Effelsberg 100-m telescope reveal that these outbursts are non-thermal in nature, implying that jet processes are the power source of the outbursts.
The MOMO results affect ongoing and future search strategies for additional binary systems using major large observatories such as the Event Horizon Telescope and, in the future, the SKA Observatory. They could enable direct radio detection and spatial resolution of the binary sources in OJ 287 and similar systems, as well as the detection of gravitational waves from these systems in the future. OJ 287 will no longer serve as a target for pulsar-timing arrays due to the derived black hole mass of 100 million solar masses, but will be within the range of future space-based observatories (upon coalescence).
“Our results have strong implications for theoretical modeling of binary supermassive black hole systems and their evolution, for understanding the physics of accretion and ejection of matter in the vicinity of supermassive black holes, and for the electromagnetic identification of binary systems in general”, concludes Stefanie Komossa.
The research team comprises S. Komossa, D. Grupe, A. Kraus, M.A. Gurwell, Z. Haiman, F.K. Liu, A. Tchekhovskoy, L.C. Gallo, M. Berton, R. Blandford, J.L. Gómez, and A.G. Gonzalez (MNRAS Letter), and S. Komossa, A. Kraus, D. Grupe, A.G. Gonzalez, M.A. Gurwell, L.C. Gallo, F.K. Liu, I. Myserlis, T.P. Krichbaum, S. Laine, U. Bach, J.L. Gómez, M.L. Parker, S. Yao, and M. Berton (ApJ Paper). Stefanie Komossa, Alex Kraus, Thomas Krichbaum, Uwe Bach and Su Yao are affiliated with the MPIfR.
MNRAS Letters
The Astrophysical Journal
See the above science paper for instructive material with images.
See the full article here .
Comments are invited and will be appreciated, especially if the reader finds any errors which I can correct. Use “Reply”.

five-ways-keep-your-child-safe-school-shootings
Please help promote STEM in your local schools.

Stem Education Coalition
MPIFR campus
Effelsberg Radio Telescope- a radio telescope in the Ahr Hills (part of the Eifel) in Bad Münstereifel(DE)
The MPG Institute for Radio Astronomy [MPG Institut für Radioastronomie] (DE) is located in Bonn, Germany. It is one of 80 institutes in the MPG Society.
By combining the already existing radio astronomy faculty of the University of Bonn led by Otto Hachenberg with the new MPG institute the MPG Institute for Radio Astronomy was formed. In 1972 the 100-m radio telescope in Effelsberg was opened. The institute building was enlarged in 1983 and 2002.
The institute was founded in 1966 by the MPG Society as the “MPG Institut für Radioastronomie (MPIfR) (DE)”.
The foundation of the institute was closely linked to plans in the German astronomical community to construct a competitive large radio telescope in (then) West Germany. In 1964, Professors Friedrich Becker, Wolfgang Priester and Otto Hachenberg of the Astronomische Institute der Universität Bonn submitted a proposal to the Stiftung Volkswagenwerk for the construction of a large fully steerable radio telescope.
In the same year the Stiftung Volkswagenwerk approved the funding of the telescope project but with the condition that an organization should be found, which would guarantee the operations. It was clear that the operation of such a large instrument was well beyond the possibilities of a single university institute.
Already in 1965 the MPG Society decided in principle to found the MPG Institut für Radioastronomie. Eventually, after a series of discussions, the institute was officially founded in 1966.

MPG Society for the Advancement of Science [MPG Gesellschaft zur Förderung der Wissenschaften e. V.] is a formally independent non-governmental and non-profit association of German research institutes founded in 1911 as the Kaiser Wilhelm Society and renamed the Max Planck Society in 1948 in honor of its former president, theoretical physicist Max Planck. The society is funded by the federal and state governments of Germany as well as other sources.
According to its primary goal, the MPG Society supports fundamental research in the natural, life and social sciences, the arts and humanities in its 83 (as of January 2014) MPG Institutes. The society has a total staff of approximately 17,000 permanent employees, including 5,470 scientists, plus around 4,600 non-tenured scientists and guests. Society budget for 2015 was about €1.7 billion.
The MPG Institutes focus on excellence in research. The MPG Society has a world-leading reputation as a science and technology research organization, with 33 Nobel Prizes awarded to their scientists, and is generally regarded as the foremost basic research organization in Europe and the world. In 2013, the Nature Publishing Index placed the MPG institutes fifth worldwide in terms of research published in Nature journals (after Harvard University, The Massachusetts Institute of Technology, Stanford University and The National Institutes of Health). In terms of total research volume (unweighted by citations or impact), the Max Planck Society is only outranked by The Chinese Academy of Sciences [中国科学院](CN), The Russian Academy of Sciences [Росси́йская акаде́мия нау́к](RU) and Harvard University. The Thomson Reuters-Science Watch website placed the MPG Society as the second leading research organization worldwide following Harvard University, in terms of the impact of the produced research over science fields.
The MPG Society and its predecessor Kaiser Wilhelm Society hosted several renowned scientists in their fields, including Otto Hahn, Werner Heisenberg, and Albert Einstein.
History
The organization was established in 1911 as the Kaiser Wilhelm Society, or Kaiser-Wilhelm-Gesellschaft (KWG), a non-governmental research organization named for the then German emperor. The KWG was one of the world’s leading research organizations; its board of directors included scientists like Walther Bothe, Peter Debye, Albert Einstein, and Fritz Haber. In 1946, Otto Hahn assumed the position of President of KWG, and in 1948, the society was renamed the Max Planck Society (MPG) after its former President (1930–37) Max Planck, who died in 1947.
The MPG Society has a world-leading reputation as a science and technology research organization. In 2006, the Times Higher Education Supplement rankings of non-university research institutions (based on international peer review by academics) placed the MPG Society as No.1 in the world for science research, and No.3 in technology research (behind AT&T Corporation and The DOE’s Argonne National Laboratory.
The domain mpg.de attracted at least 1.7 million visitors annually by 2008 according to a Compete.com study.
MPG Institutes and research groups
The MPG Society consists of over 80 research institutes. In addition, the society funds a number of Max Planck Research Groups (MPRG) and International Max Planck Research Schools (IMPRS). The purpose of establishing independent research groups at various universities is to strengthen the required networking between universities and institutes of the Max Planck Society.
The research units are primarily located across Europe with a few in South Korea and the U.S. In 2007, the Society established its first non-European centre, with an institute on the Jupiter campus of Florida Atlantic University (US) focusing on neuroscience.
The MPG Institutes operate independently from, though in close cooperation with, the universities, and focus on innovative research which does not fit into the university structure due to their interdisciplinary or transdisciplinary nature or which require resources that cannot be met by the state universities.
Internally, MPG Institutes are organized into research departments headed by directors such that each MPI has several directors, a position roughly comparable to anything from full professor to department head at a university. Other core members include Junior and Senior Research Fellows.
In addition, there are several associated institutes:
International Max Planck Research Schools
Together with the Association of Universities and other Education Institutions in Germany, the Max Planck Society established numerous International Max Planck Research Schools (IMPRS) to promote junior scientists:
• Cologne Graduate School of Ageing Research, Cologne
• International Max Planck Research School for Intelligent Systems, at the Max Planck Institute for Intelligent Systems located in Tübingen and Stuttgart
• International Max Planck Research School on Adapting Behavior in a Fundamentally Uncertain World (Uncertainty School), at the Max Planck Institutes for Economics, for Human Development, and/or Research on Collective Goods
• International Max Planck Research School for Analysis, Design and Optimization in Chemical and Biochemical Process Engineering, Magdeburg
• International Max Planck Research School for Astronomy and Cosmic Physics, Heidelberg at the MPI for Astronomy
• International Max Planck Research School for Astrophysics, Garching at the MPI for Astrophysics
• International Max Planck Research School for Complex Surfaces in Material Sciences, Berlin
• International Max Planck Research School for Computer Science, Saarbrücken
• International Max Planck Research School for Earth System Modeling, Hamburg
• International Max Planck Research School for Elementary Particle Physics, Munich, at the MPI for Physics
• International Max Planck Research School for Environmental, Cellular and Molecular Microbiology, Marburg at the Max Planck Institute for Terrestrial Microbiology
• International Max Planck Research School for Evolutionary Biology, Plön at the Max Planck Institute for Evolutionary Biology
• International Max Planck Research School “From Molecules to Organisms”, Tübingen at the Max Planck Institute for Developmental Biology
• International Max Planck Research School for Global Biogeochemical Cycles, Jena at the Max Planck Institute for Biogeochemistry
• International Max Planck Research School on Gravitational Wave Astronomy, Hannover and Potsdam MPI for Gravitational Physics
• International Max Planck Research School for Heart and Lung Research, Bad Nauheim at the Max Planck Institute for Heart and Lung Research
• International Max Planck Research School for Infectious Diseases and Immunity, Berlin at the Max Planck Institute for Infection Biology
• International Max Planck Research School for Language Sciences, Nijmegen
• International Max Planck Research School for Neurosciences, Göttingen
• International Max Planck Research School for Cognitive and Systems Neuroscience, Tübingen
• International Max Planck Research School for Marine Microbiology (MarMic), joint program of the Max Planck Institute for Marine Microbiology in Bremen, the University of Bremen, the Alfred Wegener Institute for Polar and Marine Research in Bremerhaven, and the Jacobs University Bremen
• International Max Planck Research School for Maritime Affairs, Hamburg
• International Max Planck Research School for Molecular and Cellular Biology, Freiburg
• International Max Planck Research School for Molecular and Cellular Life Sciences, Munich
• International Max Planck Research School for Molecular Biology, Göttingen
• International Max Planck Research School for Molecular Cell Biology and Bioengineering, Dresden
• International Max Planck Research School Molecular Biomedicine, program combined with the ‘Graduate Programm Cell Dynamics And Disease’ at the University of Münster and the Max Planck Institute for Molecular Biomedicine
• International Max Planck Research School on Multiscale Bio-Systems, Potsdam
• International Max Planck Research School for Organismal Biology, at the University of Konstanz and the Max Planck Institute for Ornithology
• International Max Planck Research School on Reactive Structure Analysis for Chemical Reactions (IMPRS RECHARGE), Mülheim an der Ruhr, at the Max Planck Institute for Chemical Energy Conversion
• International Max Planck Research School for Science and Technology of Nano-Systems, Halle at Max Planck Institute of Microstructure Physics
• International Max Planck Research School for Solar System Science at the University of Göttingen hosted by MPI for Solar System Research
• International Max Planck Research School for Astronomy and Astrophysics, Bonn, at the MPI for Radio Astronomy (formerly the International Max Planck Research School for Radio and Infrared Astronomy)
• International Max Planck Research School for the Social and Political Constitution of the Economy, Cologne
• International Max Planck Research School for Surface and Interface Engineering in Advanced Materials, Düsseldorf at Max Planck Institute for Iron Research GmbH
• International Max Planck Research School for Ultrafast Imaging and Structural Dynamics, Hamburg
Max Planck Schools
• Max Planck School of Cognition
• Max Planck School Matter to Life
• Max Planck School of Photonics
Max Planck Center
• The Max Planck Centre for Attosecond Science (MPC-AS), POSTECH Pohang
• The Max Planck POSTECH Center for Complex Phase Materials, POSTECH Pohang
Max Planck Institutes
Among others:
• Max Planck Institute for Neurobiology of Behavior – caesar, Bonn
• Max Planck Institute for Aeronomics in Katlenburg-Lindau was renamed to Max Planck Institute for Solar System Research in 2004;
• Max Planck Institute for Biology in Tübingen was closed in 2005;
• Max Planck Institute for Cell Biology in Ladenburg b. Heidelberg was closed in 2003;
• Max Planck Institute for Economics in Jena was renamed to the Max Planck Institute for the Science of Human History in 2014;
• Max Planck Institute for Ionospheric Research in Katlenburg-Lindau was renamed to Max Planck Institute for Aeronomics in 1958;
• Max Planck Institute for Metals Research, Stuttgart
• Max Planck Institute of Oceanic Biology in Wilhelmshaven was renamed to Max Planck Institute of Cell Biology in 1968 and moved to Ladenburg 1977;
• Max Planck Institute for Psychological Research in Munich merged into the Max Planck Institute for Human Cognitive and Brain Sciences in 2004;
• Max Planck Institute for Protein and Leather Research in Regensburg moved to Munich 1957 and was united with the Max Planck Institute for Biochemistry in 1977;
• Max Planck Institute for Virus Research in Tübingen was renamed as Max Planck Institute for Developmental Biology in 1985;
• Max Planck Institute for the Study of the Scientific-Technical World in Starnberg (from 1970 until 1981 (closed)) directed by Carl Friedrich von Weizsäcker and Jürgen Habermas.
• Max Planck Institute for Behavioral Physiology
• Max Planck Institute of Experimental Endocrinology
• Max Planck Institute for Foreign and International Social Law
• Max Planck Institute for Physics and Astrophysics
• Max Planck Research Unit for Enzymology of Protein Folding
• Max Planck Institute for Biology of Ageing
Like this:
Like Loading...
Reply