Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:


Astronomer’s Discovery Poses Challenge to Galaxy Formation Theories

A team led by an Indiana University astronomer has found a sample of massive galaxies with properties that suggest that they may have formed relatively recently.

This would run counter to the widely-held belief that massive, luminous galaxies (like our own Milky Way Galaxy) began their formation and evolution shortly after the Big Bang, some 13 billion years ago. Further research into the nature of these objects could open new windows into the study of the origin and early evolution of galaxies.

John Salzer, principal investigator for the study published today in Astrophysical Journal Letters, said that the 15 galaxies in the sample exhibit luminosities (a measure of their total light output) that indicate that they are massive systems like the Milky Way and other so-called “giant” galaxies. However, these particular galaxies are unusual because they have chemical abundances that suggest that very little stellar evolution has taken place within them. Their relatively low abundances of “heavy” elements (elements heavier than helium, called “metals” by astronomers) imply that the galaxies are cosmologically young and may have formed recently.

The chemical abundances of the galaxies, combined with some simple assumptions about how stellar evolution and chemical enrichment progress in galaxies in general, suggest that they may only be 3 or 4 billion years old, and therefore formed 9 to 10 billion years after the Big Bang. Most theories of galaxy formation predict that massive, luminous systems like these should have formed much earlier.

If this overall interpretation proves correct, the galaxies may allow astronomers to investigate phases of the galaxy formation and evolution process that have been difficult to study because they normally occur at such early times in the Universe, and therefore at very large distances from us.

“These objects may represent a unique window on the process of galaxy formation, allowing us to study relatively nearby systems that are undergoing a phase in their evolution that is analogous to the types of events that, for most galaxies, typically occurred much earlier in the history of the Universe," Salzer said.

The discoveries are the result of a multi-year survey of more than 2,400 star-forming galaxies called the Kitt Peak National Observatory International Spectroscopic Survey (KISS). The survey was designed to collect basic observational data for a large number of extragalactic emission-line sources. Additional rounds of follow-up spectroscopy for the sources discovered in the initial survey led to the discovery of the 15 luminous, low-abundance systems.

"The reason we found these types of galaxies has to do with the unique properties of the KISS survey method," Salzer said. "Galaxies were selected via their strong emission lines, which is the only way to detect these specific galaxies." Previous surveys done by others have largely missed findings these unusual galaxies.

While the hypothesis that these galaxies are cosmologically young is provocative, it is not the only possible explanation for these enigmatic systems. An alternative explanation proposes that the galaxies are the result of a recent merger between two smaller galaxies. Such a model might explain these objects, since the two-fold result of such a merger might be the reduction of metal abundances due to dilution from unprocessed gas and a brief but large increase in luminosity caused by rampant star formation. As a way to distinguish between these two scenarios, Salzer and his team intend to request observing time on NASA's Hubble Space Telescope to use high-resolution imaging to determine whether or not the systems might be products of merging.

A National Science Foundation Presidential Faculty Award to Salzer, as well as continued NSF support cumulatively totaling $1.2 million, funded the KISS survey and supporting work.

Also contributing to the Astrophysical Journal Letters paper were astronomers Anna Williams of Wesleyan University in Middletown, Conn. and Caryl Gronwall of Pennsylvania State University. Salzer is at IU while on leave from his position of professor of astronomy at Wesleyan, but expects to formally join the faculty at IU in the coming year. The authors also recognized KISS team members Gary Wegner, Drew Phillips, Jessica Werk, Laura Chomiuk, Kerrie McKinstry, Robin Ciardullo, Jeffrey Van Duyne and Vicki Sarajedini for their participation in the follow-up spectroscopic observations over the past several years.

To speak with Salzer, please contact Steve Chaplin, Indiana University Office of Communications, at 812-856-1896, or

Steve Chaplin | Newswise Science News
Further information:

More articles from Physics and Astronomy:

nachricht 'Frequency combs' ID chemicals within the mid-infrared spectral region
16.03.2018 | American Institute of Physics

nachricht Fraunhofer HHI have developed a novel single-polarization Kramers-Kronig receiver scheme
16.03.2018 | Fraunhofer-Institut für Nachrichtentechnik, Heinrich-Hertz-Institut, HHI

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: Tiny implants for cells are functional in vivo

For the first time, an interdisciplinary team from the University of Basel has succeeded in integrating artificial organelles into the cells of live zebrafish embryos. This innovative approach using artificial organelles as cellular implants offers new potential in treating a range of diseases, as the authors report in an article published in Nature Communications.

In the cells of higher organisms, organelles such as the nucleus or mitochondria perform a range of complex functions necessary for life. In the networks of...

Im Focus: Locomotion control with photopigments

Researchers from Göttingen University discover additional function of opsins

Animal photoreceptors capture light with photopigments. Researchers from the University of Göttingen have now discovered that these photopigments fulfill an...

Im Focus: Surveying the Arctic: Tracking down carbon particles

Researchers embark on aerial campaign over Northeast Greenland

On 15 March, the AWI research aeroplane Polar 5 will depart for Greenland. Concentrating on the furthest northeast region of the island, an international team...

Im Focus: Unique Insights into the Antarctic Ice Shelf System

Data collected on ocean-ice interactions in the little-researched regions of the far south

The world’s second-largest ice shelf was the destination for a Polarstern expedition that ended in Punta Arenas, Chile on 14th March 2018. Oceanographers from...

Im Focus: ILA 2018: Laser alternative to hexavalent chromium coating

At the 2018 ILA Berlin Air Show from April 25–29, the Fraunhofer Institute for Laser Technology ILT is showcasing extreme high-speed Laser Material Deposition (EHLA): A video documents how for metal components that are highly loaded, EHLA has already proved itself as an alternative to hard chrome plating, which is now allowed only under special conditions.

When the EU restricted the use of hexavalent chromium compounds to special applications requiring authorization, the move prompted a rethink in the surface...

All Focus news of the innovation-report >>>



Industry & Economy
Event News

Virtual reality conference comes to Reutlingen

19.03.2018 | Event News

Ultrafast Wireless and Chip Design at the DATE Conference in Dresden

16.03.2018 | Event News

International Tinnitus Conference of the Tinnitus Research Initiative in Regensburg

13.03.2018 | Event News

Latest News

Virtual reality conference comes to Reutlingen

19.03.2018 | Event News

TIB’s Visual Analytics Research Group to develop methods for person detection and visualisation

19.03.2018 | Information Technology

Tiny implants for cells are functional in vivo

19.03.2018 | Interdisciplinary Research

Science & Research
Overview of more VideoLinks >>>