Featured Research

from universities, journals, and other organizations

Small distant galaxies host supermassive black holes, astronomers find

Date:
September 16, 2011
Source:
University of California - Santa Cruz
Summary:
Using the Hubble Space Telescope to probe the distant universe, astronomers have found supermassive black holes growing in surprisingly small galaxies. The findings suggest that central black holes formed at an early stage in galaxy evolution.

Astronomers detected supermassive black holes in 28 distant, low-mass galaxies, including the four shown in these Hubble Space Telescope images.
Credit: A. Koekemoer, Space Telescope Science Institute

Using the Hubble Space Telescope to probe the distant universe, astronomers have found supermassive black holes growing in surprisingly small galaxies. The findings suggest that central black holes formed at an early stage in galaxy evolution.

"It's kind of a chicken or egg problem: Which came first, the supermassive black hole or the massive galaxy? This study shows that even low-mass galaxies have supermassive black holes," said Jonathan Trump, a postdoctoral researcher at the University of California, Santa Cruz. Trump is first author of the study, which has been accepted for publication in the Astrophysical Journal and is currently available online.

All massive galaxies host a central supermassive black hole, which may shine brightly as an active galactic nucleus if the black hole is pulling in nearby gas clouds. In the local universe, however, active black holes are rarely seen in small "dwarf" galaxies. The galaxies studied by Trump and his coauthors are about 10 billion light-years away, giving astronomers a view of galaxies as they appeared when the universe was less than a quarter of its current age.

"When we look 10 billion years ago, we're looking at the teenage years of the universe. So these are very small, young galaxies," Trump said.

The study, part of the Cosmic Assembly Near-infrared Deep Extragalactic Legacy Survey (CANDELS), used a powerful new instrument on the Hubble Space Telescope. The "slitless grism" on Hubble's WFC3 infrared camera provided detailed information about different wavelengths of light coming from the galaxies. Spectroscopy allows researchers to spread out the light from an object into its component colors or wavelengths. With Hubble's high spatial resolution, the researchers were able to get separate spectra from the center and the outer part of each galaxy. This enabled them to identify the tell-tale emissions from a central black hole.

"This is the first study that is capable of probing for the existence of small, low-luminosity black holes back in time," said coauthor Sandra Faber, University Professor of astronomy and astrophysics at UC Santa Cruz and CANDELS principal investigator. "Up to now, observations of distant galaxies have consistently reinforced the local findings--distant black holes actively accreting in big galaxies only. We now have a big puzzle: What happened to these dwarf galaxies?"

One possibility is that at least some of them are the progenitors of present-day massive galaxies like the Milky Way. "Some may remain small, and some may grow into something like the Milky Way," Trump said.

But according to Faber, both possibilities raise further questions. To become big galaxies today, the dwarf galaxies would have to grow at a rate much faster than standard models predict, she said. If they remain small, then nearby dwarf galaxies should also have central black holes. "There might be a large population of small black holes in dwarf galaxies that no one has noticed before," Faber said.

Trump noted that the distant dwarf galaxies are actively forming new stars. "Their star formation rate is about ten times that of the Milky Way," he said. "There may be a connection between that and the active galactic nuclei. When gas is available to form new stars, it's also available to feed the black hole."

In addition to the Hubble observations, the researchers obtained further evidence of active black holes in the galaxies from x-ray data acquired by NASA's Chandra X-ray Observatory. The study focused on 28 galaxies in a small patch of sky known as the Hubble Ultra Deep Field. Because each object was so small and faint, Trump combined the data from all 28 galaxies to improve the signal-to-noise ratio.

"This is a powerful technique that we can use for similar studies in the future on larger samples of objects," Trump said.

In addition to Trump and Faber, the coauthors of the paper include UC Santa Cruz astronomers Dale Kocevski, Elizabeth McGrath, David Koo, Mark Mozena, and Hassen Yesuf; Benjamin Weiner and Stephanie Juneau of the Steward Observatory; Claudia Scarlata of the University of Minnesota; Eric Bell of the University of Michigan; Elise Laird and Cyprian Rangel of Imperial College London; Renbin Yan of New York University; Hakim Atek and Harry Teplitz of the Spitzer Science Center, Caltech; Mark Dickinson and Jeyhan Kartaltepe of the National Optical Astronomical Observatories; Jennifer Donley, Henry Ferguson, Norman Grogin and Anton Koekemoer of the Space Telescope Science Institute; James Dunlop of the University of Edinburgh; Steven Finkelstein of Texas A&M University; Nimish Hathi of Carnegie Observatories; Kirpal Nandra of the Max Planck Institute for Extraterrestrial Physics; Jeffrey Newman of the University of Pittsburgh; Steven Rodney of Johns Hopkins University; and Amber Straughn of Goddard Space Flight Center.

This research is funded by NASA and the National Science Foundation.


Story Source:

The above story is based on materials provided by University of California - Santa Cruz. The original article was written by Tim Stephens. Note: Materials may be edited for content and length.


Cite This Page:

University of California - Santa Cruz. "Small distant galaxies host supermassive black holes, astronomers find." ScienceDaily. ScienceDaily, 16 September 2011. <www.sciencedaily.com/releases/2011/09/110915131601.htm>.
University of California - Santa Cruz. (2011, September 16). Small distant galaxies host supermassive black holes, astronomers find. ScienceDaily. Retrieved April 20, 2014 from www.sciencedaily.com/releases/2011/09/110915131601.htm
University of California - Santa Cruz. "Small distant galaxies host supermassive black holes, astronomers find." ScienceDaily. www.sciencedaily.com/releases/2011/09/110915131601.htm (accessed April 20, 2014).

Share This



More Space & Time News

Sunday, April 20, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

A Hoax? Cosmetics Company Wants To Brighten The Moon

A Hoax? Cosmetics Company Wants To Brighten The Moon

Newsy (Apr. 19, 2014) — FOREO, a Swedish cosmetics company, says it wants to brighten the moon to lower electricity costs. Video provided by Newsy
Powered by NewsLook.com
Raw: Space X Launches to Space Station

Raw: Space X Launches to Space Station

AP (Apr. 18, 2014) — On it's second attempt this week, The Space X company launched Friday from Cape Canaveral to ferry supplies to the International Space Station. (April 18) Video provided by AP
Powered by NewsLook.com
Unmanned Falcon 9 Rocket Blasts Off from Cape Canaveral Air Force Station in Florida

Unmanned Falcon 9 Rocket Blasts Off from Cape Canaveral Air Force Station in Florida

Reuters - US Online Video (Apr. 18, 2014) — The rocket, built and operated by Space Exploration Technologies, carries a Dragon cargo ship loaded with supplies and equipment destined for the International Space Station. Rough Cut (no reporter narration). Video provided by Reuters
Powered by NewsLook.com
Earth's Near-Twin Found Orbiting Red Dwarf

Earth's Near-Twin Found Orbiting Red Dwarf

Newsy (Apr. 17, 2014) — The newly-discovered planet is roughly the size of Earth and could have liquid water on its surface. Video provided by Newsy
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
 
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:  

Breaking News:
from the past week

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

Technology News



Save/Print:
Share:  

Free Subscriptions


Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

Get Social & Mobile


Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

Have Feedback?


Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
Mobile iPhone Android Web
Follow Facebook Twitter Google+
Subscribe RSS Feeds Email Newsletters
Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins