Featured Research

from universities, journals, and other organizations

Astronomy: World's first interferometric image at 500 GHz with ALMA Band 8 receivers

Date:
September 2, 2013
Source:
National Astronomical Observatory of Japan
Summary:
ALMA opens another window to the universe in the 500 GHz frequency band. Astronomers successfully synthesized the distribution of atomic carbon around a planetary nebula NGC 6302 in test observations with the ALMA Band 8 receiver.

Planetary Nebula NGC 6302. The right image is the composite of ALMA Band 8 (yellow) and the Hubble Space Telescope (gray). Upper left image is the whole view of NGC 6302 taken by the Hubble Space Telescope. Lower left panel shows the line profile of atomic carbon.
Credit: ALMA (ESO/NAOJ/NRAO), NASA/ESA Hubble Space Telescope

ALMA opens another window to the universe in the 500 GHz frequency band. Astronomers successfully synthesized the distribution of atomic carbon around a planetary nebula NGC 6302 in test observations with the ALMA Band 8 receiver, developed by the National Astronomical Observatory of Japan (NAOJ). This is the first 500 GHz band astronomical image captured by a radio interferometer with unprecedentedly high resolution.

ALMA has 10 receiver bands to cover a wide range of observing frequency. All antennas are equipped with dedicated receivers for each frequency band. NAOJ assumes the development of three bands: Band 4 (receiving frequency: 125 to 163 GHz, millimeter-wave); Band 8 (385 to 500 GHz, submillimeter-wave); and Band 10 (787 to 950 GHz, Terahertz-wave).

The frequency band observable with the Band 8 receiver covers a wide range of radio emission lines from various atoms and molecules. Among them, one of the most attractive targets for many astronomers is the emission from atomic carbon at 492 GHz. What can we expect to see from it?The main component of the cosmic gas is hydrogen. The abundance of carbon is only 1/3000 of that of hydrogen, although carbon is the third most abundant element in the universe. The cosmic gas can be classified into three groups by its temperature and density; "plasma cloud" (number density of plasma particles: 0.01 per 1 cm3, temperature: several million degrees Celsius), "atomic cloud" (number density of atom: 10 per 1 cm3, temperature: -160 degrees Celsius), and "molecular cloud" (number density of molecule: 10000 per 1 cm3, temperature: -- 260 degrees Celsius). Dense regions of atomic cloud grow into molecular cloud, and molecular cloud with increased density becomes a seedbed of stars. On the other hand, molecules composing molecular cloud dissociate into atoms when exposed to intense ultraviolet light. Detailed study of the distributions of atomic cloud and molecular cloud gives us insights into the evolution of cosmic gas. In particular, observation of carbon atom is important not only in studying the distribution and characteristics of atomic cloud, but also in exploring chemistry in the universe because various complex molecules are formed from chemical reactions between carbon atom and other atoms such as oxygen and hydrogen.

So far, observations in the 500 GHz band, including emission line from cosmic carbon atom, have been made with single dish radio telescopes such as the University of Tokyo's Mt. Fuji Submillimeter Telescope and Caltech Submillimeter Observatory. The typical spatial resolution of those observations is 15 arcseconds or larger (1 arcsecond corresponds to 1/3600 of 1 degree), which is far worse than the resolution of existing 8-meter class optical telescopes (0.1 arcsecond). ALMA is the first radio interferometer which allows observations in this frequency range with remarkably improved resolution compared to single dish telescopes. This time, the Band 8 receivers were installed in five 7-m antennas developed by Japan and achieved a high resolution of 3.5 arcseconds. By installing the receiver into all the ALMA antennas, the resolution becomes even better by 400 times. Astronomers around the world have high expectations for observations with Band 8.

Yutaro Sekimoto, an associate professor at NAOJ and the leader of the Band 8 receiver development team at the NAOJ's Advanced Technology Center says "I deeply appreciate long and hard efforts of all staff to realize ALMA observation of carbon atom. I expect further ALMA observations will unveil the evolution process of interstellar matter." Naohisa Sato, a member of the development team, says "We went through difficult times during receiver production phase. We made a number of adjustments and replacements to achieve required performance for every receiver. I am really happy with this successful result."

NGC 6302 is a planetary nebula, which is in the final stage of the life of a star with a mass several times that of the Sun. Visible light image shows a bipolar shape of gas ejected from the dying star. ALMA with the Band 8 receivers targeted at the center of the nebula and revealed that the distribution of carbon atom is concentrated in a small part, which is similar to a dust and gas disk around the central star that has been found by previous observations with other telescopes. Further observations of carbon atom with better resolution will give us more detailed view of the chemical environment in the nebula.


Story Source:

The above story is based on materials provided by National Astronomical Observatory of Japan. Note: Materials may be edited for content and length.


Cite This Page:

National Astronomical Observatory of Japan. "Astronomy: World's first interferometric image at 500 GHz with ALMA Band 8 receivers." ScienceDaily. ScienceDaily, 2 September 2013. <www.sciencedaily.com/releases/2013/09/130902101524.htm>.
National Astronomical Observatory of Japan. (2013, September 2). Astronomy: World's first interferometric image at 500 GHz with ALMA Band 8 receivers. ScienceDaily. Retrieved April 24, 2014 from www.sciencedaily.com/releases/2013/09/130902101524.htm
National Astronomical Observatory of Japan. "Astronomy: World's first interferometric image at 500 GHz with ALMA Band 8 receivers." ScienceDaily. www.sciencedaily.com/releases/2013/09/130902101524.htm (accessed April 24, 2014).

Share This



More Space & Time News

Thursday, April 24, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Nuclear-Level Asteroids Might Be More Common Than We Realize

Nuclear-Level Asteroids Might Be More Common Than We Realize

Newsy (Apr. 23, 2014) The B612 Foundation says asteroids strike Earth much more often than previously thought, and are hoping to build an early warning system. Video provided by Newsy
Powered by NewsLook.com
NASA Chief Outlines Plan for Human Mission to Mars

NASA Chief Outlines Plan for Human Mission to Mars

AFP (Apr. 22, 2014) NASA administrator Charles Bolden, speaking at the 'Human to Mars Summit' in Washington, says that learning more about the Red Planet can help answer the 'fundamental question' of 'life beyond Earth'. Duration: 00:48 Video provided by AFP
Powered by NewsLook.com
Nasa Gives You An Excuse to Post a Selfie on Earth Day

Nasa Gives You An Excuse to Post a Selfie on Earth Day

TheStreet (Apr. 22, 2014) NASA is inviting all social media users to take a selfie of themselves alongside nature and to post it to Twitter, Facebook, Flickr, Instagram, or Google Plus with the hashtag #globalselfie. NASA's goal is to crowd-source a collection of snapshots of the earth, ground-up, that will be used to create one "unique mosaic of the Blue Marble." This image will be available to all in May. Since this is probably one of the few times posting a selfie to Twitter won't be embarrassing, we suggest you give it a go for a good cause. Video provided by TheStreet
Powered by NewsLook.com
SpaceX's Dragon Spacecraft Captured by International Space Station

SpaceX's Dragon Spacecraft Captured by International Space Station

Reuters - US Online Video (Apr. 20, 2014) SpaceX's unmanned Dragon spacecraft makes a scheduled Easter Sunday rendezvous with the International Space Station. Rough Cut (no reporter narration). Video provided by Reuters
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