heic0805 — Science Release

Hubble finds strong contender for galaxy distance record

12 February 2008

The NASA/ESA Hubble Space Telescope, with a boost from a natural "zoom lens", has found the strongest evidence so far for a galaxy with a redshift significantly above 7. It is likely to be one of the youngest and brightest galaxies ever seen right after the cosmic "dark ages", just 700 million years after the beginning of our Universe (redshift ~7.6).


"We certainly were surprised to find such a bright young galaxy 13 billion years in the past", said astronomer Garth Illingworth of the University of California, Santa Cruz, USA and a member of the research team. "This is the most detailed look to date at an object so far back in time."

According to the authors, the measurements are "highly reliable'. "This object is the strongest candidate for the most distant galaxy so far", states team member Piero Rosati from ESO, Germany.




"This galaxy presumably is one of the many galaxies that helped end the dark ages", said astronomer Larry Bradley of Johns Hopkins University in Baltimore, USA, and leader of the study. "Astronomers are fairly certain that high-energy objects such as quasars did not provide enough energy to end the dark ages of the Universe. But many young star-forming galaxies may have produced enough energy to end it."

The galaxy is so far away it did not appear in visible light images taken with Hubble's Advanced Camera for Surveys, because its light is stretched to infrared wavelengths by the Universe's expansion. It took Hubble's NICMOS, Spitzer and a trick of nature called gravitational lensing to see the faraway galaxy.


Though the diffuse light of the faraway object is nearly impossible to see, gravitational lensing has increased its brightness by nearly 10 times, making it bright enough for Hubble and Spitzer to detect. A telltale sign of the lensing is the smearing of the images of galaxies behind Abell 1689 into arcs by the gravitational warping of space by the intervening galaxy cluster. Piero Rosati says: "This galaxy lies near the region where the galaxy cluster produces the highest magnification -- which was essential to bring this galaxy within reach of Hubble and Spitzer."

Spitzer's images show that the galaxy's mass is typical of galaxies in the early Universe. Its mass is equivalent to several billions of stars like our Sun, or just a tiny fraction of the mass of the Milky Way.

"This observation confirms previous Hubble studies that star birth happens in very tiny regions compared with the size of the final galaxy", Illingworth said.


"This galaxy will certainly be one of the first objects that will be observed by JWST", said team member Holland Ford of Johns Hopkins University. "This galaxy is so bright that JWST will see its detailed structure. This object is a pathfinder for JWST for deciphering what is happening in young galaxies."

The astronomers noted that the faraway galaxy also would be an ideal target for the ESO/NRAO/NAOJ Atacama Large Millimeter Array (ALMA), which, when completed in 2012, will be the most powerful radio telescope in the world. "ALMA and JWST working together would be an ideal combination to really understand this galaxy", Illingworth said, noting that: "JWST's images and ALMA's measurement of the gas motions will provide revolutionary insights into the very youngest galaxies."

The astronomers will conduct follow-up observations with infrared spectroscopy to confirm the galaxy's distance using ESO's VLT and the Keck telescope atop Mauna Kea in Hawaii.

The results will be published in the Astrophysical Journal.



Image credit: NASA, ESA, L. Bradley (JHU), R. Bouwens (UCSC), H. Ford (JHU)and G. Illingworth (UCSC)



Narciso Benitez
Instituto de Astrofísica de Andalucía, Spain
Tel: +34 958 121 311
E-mail: benitez@iaa.es

Larry Bradley
Johns Hopkins University, Baltimore, Md.
Tel: +1-410-516-5108
E-mail: ldb@pha.jhu.edu

Piero Rosati
ESO, Munich, Germany
Tel: +49 (0)89 320 06 589
E-mail: prosati@eso.org

Garth Ilingworth
University of California, Santa Cruz, USA
Tel: +1-831-459-2843
E-mail: gdi@ucolick.org

Lars Lindberg Christensen
Hubble/ESA, Garching, Germany
E-mail: lars@eso.org

Ray Villard
Space Telescope Science Institute, Baltimore, USA
Tel: +1-410-338-4514
E-mail: villard@stsci.edu

About the Release

Release No.:heic0805


A Young Galaxy Brimming with Star Birth (artist's impression)
A Young Galaxy Brimming with Star Birth (artist's impression)
Cosmic Epochs
Cosmic Epochs
Abell 1689
Abell 1689
Arc in Visible light (Hubble)
Arc in Visible light (Hubble)
Arc in infrared light (Hubble)
Arc in infrared light (Hubble)
Arc in infrared light (Spitzer)
Arc in infrared light (Spitzer)


A zoom into Abell 1689 and galaxy distance record contender
A zoom into Abell 1689 and galaxy distance record contender
Panning and zooming on Abell 1689
Panning and zooming on Abell 1689

Print Layouts



PDF File
184.3 KB
Text File
7.8 KB
Word File
201.5 KB

Also see our