Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Cosmic lenses support finding on faster than expected expansion of the Universe Galaxies as lenses

26.01.2017

Using galaxies as giant gravitational lenses, an international group of astronomers headed by Max Planck@TUM tenure track professor Sherry Suyu measured independently how fast the Universe is expanding. The newly measured expansion rate for the local Universe is consistent with earlier findings. These are, however, in intriguing disagreement with measurements of the early Universe. This hints at a fundamental problem at the very heart of our understanding of the cosmos.

The Hubble constant — the rate at which the Universe is expanding — is one of the fundamental quantities describing our Universe. A group of astronomers, the H0LiCOW collaboration (H0 Lenses in COsmograil’s Wellspring), used the NASA/ESA Hubble Space Telescope and other telescopes in space and on the ground to observe five galaxies in order to arrive at an independent measurement of the Hubble constant.


HE0435-1223, located in the centre of this wide-field image, is among the five best lensed quasars discovered to date.

Image: ESA/Hubble, NASA


HE0435-1223 is among the five best lensed quasars discovered to date. The foreground galaxy creates four almost evenly distributed images of the distant quasar around it.

Image: Suyu et al. / ESA/Hubble, NASA

The new measurement is completely independent of — but in excellent agreement with — other measurements of the Hubble constant in the local Universe that used Cepheid variable stars and supernovae as points of reference.

The collaboration is led by Sherry Suyu, who recently moved from the Academia Sinica Institute of Astronomy and Astrophysics (ASIAA) in Taipei (Taiwan) to Garching (Germany) where she works now as a group leader at the Max Planck Institute for Astrophysics and at the Technical University of Munich as a tenure track professor in the Max Planck@TUM program.

A new kind of physics?

However, the value measured by Suyu and her team, as well as those measured using Cepheids and supernovae, are different from the measurement made by the ESA Planck satellite. But there is an important distinction — Planck measured the Hubble constant for the early Universe by observing the cosmic microwave background.

While the value for the Hubble constant determined by Planck fits with our current understanding of the cosmos, the values obtained by the different groups of astronomers for the local Universe are in disagreement with our accepted theoretical model of the Universe.

“The expansion rate of the Universe is now starting to be measured in different ways with such high precision that actual discrepancies may possibly point towards new physics beyond our current knowledge of the Universe,” elaborates Suyu.

Seeing around the corner with gravitational lenses

The targets of the study were massive galaxies positioned between Earth and very distant quasars — incredibly luminous galaxy cores. The light from the more distant quasars is bent around the huge masses of the galaxies as a result of strong gravitational lensing – an effect first predicted by Swiss astronomer Fritz Zwicky 80 years ago. This creates multiple images of the background quasar and its host galaxy, some smeared into extended arcs.

Because galaxies do not create perfectly spherical distortions in the fabric of space and the lensing galaxies and quasars are not perfectly aligned, the light from the different images of the background quasar follows paths which have slightly different lengths.

Since the brightness of quasars changes over time, astronomers can see the different images flicker at different times, the delays between them depending on the lengths of the paths the light has taken. These delays are directly related to the value of the Hubble constant.

“Our method is the most simple and direct way to measure the Hubble constant as it only uses geometry and General Relativity, no other assumptions,” explains co-lead Frédéric Courbin from EPFL, Switzerland.

Using the accurate measurements of the time delays between the multiple images, as well as computer models, allowed the team to determine the Hubble constant to an impressively high precision: the error is only 3.8 percent. “To reach that accuracy, we even considered the lensing effects of all other nearby galaxies in our analysis,” explains Stefan Hilbert from the Cluster of Excellence Origin and Structure of the Universe.

“An accurate measurement of the Hubble constant is one of the most sought-after prizes in cosmological research today,” highlights team member Vivien Bonvin, from EPFL, Switzerland. And Suyu adds: “The Hubble constant is crucial for modern astronomy as it can help to confirm or refute whether our picture of the Universe — composed of dark energy, dark matter and normal matter — is actually correct, or if we are missing something fundamental.”

Further information:

Max Planck@TUM: TUM and the Max-Planck-Gesellschaft (MPG) offer a joined career path for highly qualified early career scientists. It combines research as a Max Planck Research Group Leader with a Tenure Track professorship at TUM. For more information, please see here: https://www.tum.de/en/about-tum/working-at-tum/faculty-recruiting/tum-faculty-te...

Instruments used: The study used, alongside the NASA/ESA Hubble Space Telescope, the Keck Telescope, ESO’s Very Large Telescope, the Subaru Telescope, the Gemini Telescope, the Victor M. Blanco Telescope, the Canada-France-Hawaii telescope and the NASA Spitzer Space Telescope. In addition, data from the Swiss 1.2-metre Leonhard Euler Telescope and the MPG/ESO 2.2-metre telescope in Chile were used.

Precision of the Hubble constant: The H0LiCOW team determined a value for the Hubble constant of 71.9±2.7 kilometres per second per Megaparsec. In 2016, scientists using the Hubble Space Telescope measured a value of 73.24±1.74 kilometres per second per Megaparsec. In 2015, the ESA Planck Satellite measured the constant with the highest precision so far and obtained a value of 66.93±0.62 kilometres per second per Megaparsec.

Publications:

This research was presented in a series of papers to appear in the Monthly Notices of the Royal Astronomical Society:
1. Suyu et al.; H0LiCOW I. Program Overview
Submitted to MNRAS, https://arxiv.org/abs/1607.00017
2. Sluse et al.; H0LiCOW II. Spectroscopic survey and galaxy-group identification of the strong gravitational lens system HE0435-1223
Submitted to MNRAS, https://arxiv.org/abs/1607.00382
3. Rusu et al.; H0LiCOW III. Quantifying the effect of mass along the line of sight to the gravitational lens HE 0435-1223 through weighted galaxy counts
Submitted to MNRAS, https://arxiv.org/abs/1607.01047
4. Wong et al.; H0LiCOW IV. Lens mass model of HE 0435-1223 and blind measurement of its time-delay distance for cosmology
Accepted by MNRAS, https://arxiv.org/abs/1607.01403
DOI: https://dx.doi.org/10.1093/mnras/stw3006
5. Bonvin et al.; H0LiCOW V. New COSMOGRAIL time delays of HE 0435−1223: H0 to 3.8% precision from strong lensing in a flat ΛCDM model
Accepted by MNRAS, https://arxiv.org/abs/1607.01790
DOI: https://dx.doi.org/10.1093/mnras/stw3077
6. Ding et al.; H0LiCOW VI. Testing the fidelity of lensed quasar host galaxy reconstruction
MNRAS (2016) 465 (4): 4634-4649, https://arxiv.org/abs/1610.08504
DOI: https://dx.doi.org/10.1093/mnras/stw3078

Contacts:

Sherry Suyu
Max Planck Institute for Astrophysics
Garching, Germany
Tel.: +49 89 30000 2015
E-mail: suyu@mpa-garching.mpg.de

Hannelore Hämmerle
Press officer
Max Planck Institute for Astrophysics
Garching, Germany
Tel.: +49 89 30000 3980
E-mail: pr@mpa-garching.mpg.de

Stefan Hilbert
Junior Research Group Leader
Excellence Cluster Universe
Tel: +49 89 35831 7148
E-mail: stefan.hilbert@universe-cluster.de

Dr. Ulrich Marsch | Technische Universität München
Further information:
http://www.tum.de

Further reports about: Cosmic ESA Galaxies Space Telescope Telescope Universe cosmic lenses quasars

More articles from Physics and Astronomy:

nachricht NASA's James Webb Space Telescope completes final cryogenic testing
21.11.2017 | NASA/Goddard Space Flight Center

nachricht Previous evidence of water on mars now identified as grainflows
21.11.2017 | US Geological Survey

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: Nanoparticles help with malaria diagnosis – new rapid test in development

The WHO reports an estimated 429,000 malaria deaths each year. The disease mostly affects tropical and subtropical regions and in particular the African continent. The Fraunhofer Institute for Silicate Research ISC teamed up with the Fraunhofer Institute for Molecular Biology and Applied Ecology IME and the Institute of Tropical Medicine at the University of Tübingen for a new test method to detect malaria parasites in blood. The idea of the research project “NanoFRET” is to develop a highly sensitive and reliable rapid diagnostic test so that patient treatment can begin as early as possible.

Malaria is caused by parasites transmitted by mosquito bite. The most dangerous form of malaria is malaria tropica. Left untreated, it is fatal in most cases....

Im Focus: A “cosmic snake” reveals the structure of remote galaxies

The formation of stars in distant galaxies is still largely unexplored. For the first time, astron-omers at the University of Geneva have now been able to closely observe a star system six billion light-years away. In doing so, they are confirming earlier simulations made by the University of Zurich. One special effect is made possible by the multiple reflections of images that run through the cosmos like a snake.

Today, astronomers have a pretty accurate idea of how stars were formed in the recent cosmic past. But do these laws also apply to older galaxies? For around a...

Im Focus: Visual intelligence is not the same as IQ

Just because someone is smart and well-motivated doesn't mean he or she can learn the visual skills needed to excel at tasks like matching fingerprints, interpreting medical X-rays, keeping track of aircraft on radar displays or forensic face matching.

That is the implication of a new study which shows for the first time that there is a broad range of differences in people's visual ability and that these...

Im Focus: Novel Nano-CT device creates high-resolution 3D-X-rays of tiny velvet worm legs

Computer Tomography (CT) is a standard procedure in hospitals, but so far, the technology has not been suitable for imaging extremely small objects. In PNAS, a team from the Technical University of Munich (TUM) describes a Nano-CT device that creates three-dimensional x-ray images at resolutions up to 100 nanometers. The first test application: Together with colleagues from the University of Kassel and Helmholtz-Zentrum Geesthacht the researchers analyzed the locomotory system of a velvet worm.

During a CT analysis, the object under investigation is x-rayed and a detector measures the respective amount of radiation absorbed from various angles....

Im Focus: Researchers Develop Data Bus for Quantum Computer

The quantum world is fragile; error correction codes are needed to protect the information stored in a quantum object from the deteriorating effects of noise. Quantum physicists in Innsbruck have developed a protocol to pass quantum information between differently encoded building blocks of a future quantum computer, such as processors and memories. Scientists may use this protocol in the future to build a data bus for quantum computers. The researchers have published their work in the journal Nature Communications.

Future quantum computers will be able to solve problems where conventional computers fail today. We are still far away from any large-scale implementation,...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Ecology Across Borders: International conference brings together 1,500 ecologists

15.11.2017 | Event News

Road into laboratory: Users discuss biaxial fatigue-testing for car and truck wheel

15.11.2017 | Event News

#Berlin5GWeek: The right network for Industry 4.0

30.10.2017 | Event News

 
Latest News

Previous evidence of water on mars now identified as grainflows

21.11.2017 | Physics and Astronomy

NASA's James Webb Space Telescope completes final cryogenic testing

21.11.2017 | Physics and Astronomy

New catalyst controls activation of a carbon-hydrogen bond

21.11.2017 | Life Sciences

VideoLinks
B2B-VideoLinks
More VideoLinks >>>