Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:


No time for change: Cosmic weight watching reveals black hole-galaxy history

Using state-of-the-art technology and sophisticated data analysis tools, a team of astronomers from the Max Planck Institute for Astronomy has developed a new and powerful technique to directly determine the mass of an active galaxy at a distance of nearly 9 billion light-years from Earth.

This pioneering method promises a new approach for studying the co-evolution of galaxies and their central black holes. First results indicate that for galaxies, the best part of cosmic history was not a time of sweeping changes.

Colours in this image of the galaxy J090543.56+043347.3 indicate whether there is gas moving towards us or away from us, and at what speed. Using this information, the researchers reconstructed the galaxy's dynamical mass. The star shape indicates the position of the galaxy's active nucleus; the surrounding contour lines indicate brightness levels for light emitted by the nucleus. Image: K. J. Inskip/MPIA

One of the most intriguing developments in astronomy over the last few decades is the realization that not only do most galaxies contain central black holes of gigantic size, but also that the mass of these central black holes are directly related to the mass of their host galaxies[1]. This correlation is predicted by the current standard model of galaxy evolution, the so-called hierarchical model, as astronomers from the Max Planck Institute for Astronomy have recently shown [2].

When astronomers look out to greater and greater distances, they look further and further into the past [3]. Investigating this black hole-galaxy mass correlation at different distances, and thus at different times in cosmic history, allows astronomers to study galaxy and black hole evolution in action.

For galaxies further away than 5 billion light-years (corresponding to a redshift of z > 0.5 [4]), such studies face considerable difficulties. The typical objects of study are so-called active galaxies, and there are well-established methods to estimate the mass of such a galaxy's central black hole [5]. It is the galaxy's mass itself that is the challenge: At such distances, standard methods of estimating a galaxy's mass become exceedingly uncertain or fail altogether.

Now, a team of astronomers from the Max Planck Institute for Astronomy, led by Dr Katherine Inskip, has, for the first time, succeeded in directly "weighing" both a galaxy and its central black hole at such a great distance using a sophisticated and novel method [6]. The galaxy, known to astronomers by the number J090543.56+043347.3 (which encodes the galaxy's position in the sky) has a distance of 8.8 billion light-years from Earth (redshift z = 1.3).

The astronomers succeeded in measuring directly the so-called dynamical mass of this active galaxy. The key idea is the following: A galaxy's stars and gas clouds orbit the galactic centre; for instance, our Sun orbits the centre of the Milky Way galaxy once every 250 million years. The stars' different orbital speeds are a direct function of the galaxy's mass distribution. Determine orbital speeds and you can determine the galaxy's total mass [7].

This is much easier said than done. In order to secure their measurement, the cosmic weightwatchers had to pull out all the stops of observational astronomy before finally obtaining a reliable value for the dynamical mass of J090543.56+043347.3. Combining this result with the mass value of the galaxy's central black hole, which the researchers measured from the same dataset, the result is the same that would be expected for a present-day galaxy. Apparently, nothing major has changed between now and then: At least out to this distance, 9 billion years into the past, the correlation between galaxies and their black holes appears to be the same as for their modern-day counterparts.

Inskip and her colleagues are already hard at work to expand their novel kind of analysis to a larger set of 15 further galaxies. If this confirms their conclusions from J090543.56+043347.3, that would indicate that, over the past 9 billion years – for more than half of the age of our Universe! – most galaxies have lived comparatively boring lives, subject to only very limited and slow change.

Contact information

Katherine Inskip (lead author)
Max Planck Institute for Astronomy
Knud Jahnke (co-author)
Max Planck Institute for Astronomy
Phone: (+49|0) 6221 – 528 398
Markus Pössel (public relations)
Max Planck Institute for Astronomy
Phone: (+49|0) 6221 – 528 261
Background information
The work described here is being published as K. J. Inskip, K. Jahnke, H.-W. Rix & G. van de Ven, "Resolving the Dynamical Mass of a z ~ 1.3 Quasi-stellar Object Host Galaxy Using SINFONI and Laser Guide Star Assisted Adaptive Optics" in the October 1 edition of the Astrophysical Journal, Volume 739, Issue 2, article id. 90 (2011).


[1] There are different characteristic masses for a galaxy, and there is currently no consensus about whether the key property related to the black hole mass is the host galaxy's total mass, the mass of its stars (leaving aside dark matter and interstellar gas), or its bulge mass (the mass contained in a central thickening observed in many galaxies known as their bulge).

[2] In the hierarchical model of galaxy evolution, galaxies evolve and grow by ingesting smaller galaxies, or through mergers with galaxies of comparable size. The prediction is published as Jahnke & Macciò 2011, Astrophysical Journal, vol. 734, article ID 92

[3] This is because light travels at a finite speed. Every time we look at the Sun, we see our mother star as it was eight minutes ago, simply because it took the light we perceive eight minutes to travel from the Sun to Earth.

[4] In an expanding universe, a distant galaxy's distance from us and the redshift of that galaxy's light (the amount that the light is shifted towards lower frequencies) are directly related. Although distances are very hard to measure directly, it is typically straightforward to determine a galaxy's redshift, and so astronomers frequently quote a galaxy's redshift, z, as an (indirect) measure of its distance.

[5] In active galaxies, the central black hole habitually swallows surrounding matter, emitting enormous amounts of electromagnetic radiation in the process. Well-established methods allow astronomers to determine the black hole's mass by studying specific properties of this radiation.

[6] Both in the title and here, "weighing" is a reference to the standard everyday method for determining a body's mass (a measure for the amount of matter contained within the body) by determining its weight (that is, measuring the force by which the Earth's gravity pulls the body downwards). The concept of weight is not applicable to large celestial objects such as stars or galaxies; the work described in this release is strictly about determining a specific galaxy's mass.

[7] There is a simple analogue within our own Solar System: Kepler's 3rd Law of Planetary Motion states that a planet's orbital period T is related to its mean distance from the Sun a, the Sun's mass M and the gravitational constant by T2 = 4 π2a3/MG. Once you know the planet's orbit and its distance from the Sun, you can determine the Sun's mass. For much closer galaxies than the one examined here, studies of dynamic mass are a common astronomical tool. Notably, such studies are a key part of the evidence for the existence of Dark Matter

Dr. Markus Pössel | Max-Planck-Institut
Further information:

More articles from Physics and Astronomy:

nachricht Astrophysicists measure precise rotation pattern of sun-like stars for the first time
21.09.2018 | NYU Abu Dhabi

nachricht Halfway mark for NOEMA, the super-telescope under construction
20.09.2018 | Max-Planck-Institut für Radioastronomie

All articles from Physics and Astronomy >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Scientists present new observations to understand the phase transition in quantum chromodynamics

The building blocks of matter in our universe were formed in the first 10 microseconds of its existence, according to the currently accepted scientific picture. After the Big Bang about 13.7 billion years ago, matter consisted mainly of quarks and gluons, two types of elementary particles whose interactions are governed by quantum chromodynamics (QCD), the theory of strong interaction. In the early universe, these particles moved (nearly) freely in a quark-gluon plasma.

This is a joint press release of University Muenster and Heidelberg as well as the GSI Helmholtzzentrum für Schwerionenforschung in Darmstadt.

Then, in a phase transition, they combined and formed hadrons, among them the building blocks of atomic nuclei, protons and neutrons. In the current issue of...

Im Focus: Patented nanostructure for solar cells: Rough optics, smooth surface

Thin-film solar cells made of crystalline silicon are inexpensive and achieve efficiencies of a good 14 percent. However, they could do even better if their shiny surfaces reflected less light. A team led by Prof. Christiane Becker from the Helmholtz-Zentrum Berlin (HZB) has now patented a sophisticated new solution to this problem.

"It is not enough simply to bring more light into the cell," says Christiane Becker. Such surface structures can even ultimately reduce the efficiency by...

Im Focus: New soft coral species discovered in Panama

A study in the journal Bulletin of Marine Science describes a new, blood-red species of octocoral found in Panama. The species in the genus Thesea was discovered in the threatened low-light reef environment on Hannibal Bank, 60 kilometers off mainland Pacific Panama, by researchers at the Smithsonian Tropical Research Institute in Panama (STRI) and the Centro de Investigación en Ciencias del Mar y Limnología (CIMAR) at the University of Costa Rica.

Scientists established the new species, Thesea dalioi, by comparing its physical traits, such as branch thickness and the bright red colony color, with the...

Im Focus: New devices based on rust could reduce excess heat in computers

Physicists explore long-distance information transmission in antiferromagnetic iron oxide

Scientists have succeeded in observing the first long-distance transfer of information in a magnetic group of materials known as antiferromagnets.

Im Focus: Finding Nemo's genes

An international team of researchers has mapped Nemo's genome

An international team of researchers has mapped Nemo's genome, providing the research community with an invaluable resource to decode the response of fish to...

All Focus news of the innovation-report >>>



Industry & Economy
Event News

"Boston calling": TU Berlin and the Weizenbaum Institute organize a conference in USA

21.09.2018 | Event News

One of the world’s most prominent strategic forums for global health held in Berlin in October 2018

03.09.2018 | Event News

4th Intelligent Materials - European Symposium on Intelligent Materials

27.08.2018 | Event News

Latest News

Astrophysicists measure precise rotation pattern of sun-like stars for the first time

21.09.2018 | Physics and Astronomy

Brought to light – chromobodies reveal changes in endogenous protein concentration in living cells

21.09.2018 | Life Sciences

"Boston calling": TU Berlin and the Weizenbaum Institute organize a conference in USA

21.09.2018 | Event News

Science & Research
Overview of more VideoLinks >>>