Meddelelse
ALMA strækker armen ud
Den længste baseline indtil nu
24. september 2014
Ved Atacama Large Millimeter/submillimeter Array (ALMA) er det for nyligt lykkedes at strække konfigurationen af antennerne længere end nogensinde før for submillimeterteleskopet ALMA. Den første af ALMAs tre forlængede arme er koblet til, og det gør det muligt at udnytte ALMAanlægget endnu bedre end før. Jo større baseline [1], des finere detaljer kan radioteleskoperne se på himlen, og dermed kan astronomerne lære meget mere om himlens objekter.
Lore er en af ALMAs to specialbyggede antennetrucks. Den fik en antenne på ryggen, og tog så sin første tur langs den nye arm, som har fået navnet Pampa la Bola. Antennen blev parkeret mere end syv kilometer fra sin fjerneste nabo, og det er endnu en teknisk milepæl her oppe i Atacamaørkenen i Chile, 5.000 m over havet.
Med denne nye antenneafstand er baseline mere end firedoblet i forhold til tidligere. Nu kan ALMA se astronomiske fænomener betragteligt skarpere end tidligere, og der er forsøg i gang med at teste endnu længere baselines.
Catherine Vlahakis, som er videnskabelig leder af ALMAs Long Baseline Campaign-programmet, siger: "det er et vigtigt teknisk fremskridt, at det nu er lykkedes at koble antennerne sammen over denne store afstand. Vi får endnu bedre mulighed for at se objekterne i Universet i endnu finere detalje med ALMA".
Ed Fomalont, som er videnskabelig leder af ALMAs Long Baseline Campaign forklarer: "Når vi kombinerer signalerne fra antennerne får vi mønstre, som kaldes "fringes". De fringes, som vi fik fra antennen syv kilometer væk var præcis så skarpe og kraftige, som vi får brug for, når vi skal have højkvalitetsbilleder fra de yderligere antenner, som vi vil flytte ud på disse store afstande".
Catherine Vlahakis tilføjer: "vi flytter efterhånden adskillige antenner lige så langt væk. Dette her er kun første trin. Når resten af antennerne er på plads, kan vi begynde at teste observationer af astronomiske objekter ved en finere vinkelopløsning. Det giver os endnu finere detaljer, end ALMA indtil nu har givet os".
I løbet af de næste to måneder fortsætter afprøvningen af anlægget i denne spredte konfiguration. Hvis alt går som forventet, kan ALMA snart tilbyde astronomerne helt nye muligheder for observationer med lange baselines.
Note
[1] Baseline eller basislinie er afstanden imellem de fjerneste teleskoper i en opstilling med flere teleskoper, som for eksempel ALMA. De optiske love for radiobølgernes vekselvirkning, interferometri bevirker, at to teleskoper fjernt fra hinanden, hvis de kobles omhyggeligt sammen, kan give et lige så skarpt billede, som hvis man havde et kæmpeteleskop med samme diameter som afstanden; her for eksempel 7 kilometer. Med små teleskoper langt fra hinanden får man et skarpt billede, men følsomheden er naturligvis ikke nær så stor, som med det teoretiske kæmpeteleskop.
Kontakter
Ole J. Knudsen
ESON-Danmark, IDA, Aarhus Universitet
Tlf: 8715 5419
eson-denmark@eso.org
Om meddelelsen
| Id: | ann14069 |
Billeder
Our use of Cookies
We use cookies that are essential for accessing our websites and using our services. We also use cookies to analyse, measure and improve our websites’ performance, to enable content sharing via social media and to display media content hosted on third-party platforms.
ESO Cookies Policy
The European Organisation for Astronomical Research in the Southern Hemisphere (ESO) is the pre-eminent intergovernmental science and technology organisation in astronomy. It carries out an ambitious programme focused on the design, construction and operation of powerful ground-based observing facilities for astronomy.
This Cookies Policy is intended to provide clarity by outlining the cookies used on the ESO public websites, their functions, the options you have for controlling them, and the ways you can contact us for additional details.
What are cookies?
Cookies are small pieces of data stored on your device by websites you visit. They serve various purposes, such as remembering login credentials and preferences and enhance your browsing experience.
Categories of cookies we use
Essential cookies (always active): These cookies are strictly necessary for the proper functioning of our website. Without these cookies, the website cannot operate correctly, and certain services, such as logging in or accessing secure areas, may not be available; because they are essential for the website’s operation, they cannot be disabled.
Functional Cookies: These cookies enhance your browsing experience by enabling additional features and personalization, such as remembering your preferences and settings. While not strictly necessary for the website to function, they improve usability and convenience; these cookies are only placed if you provide your consent.
Analytics cookies: These cookies collect information about how visitors interact with our website, such as which pages are visited most often and how users navigate the site. This data helps us improve website performance, optimize content, and enhance the user experience; these cookies are only placed if you provide your consent. We use the following analytics cookies.
Matomo Cookies:
This website uses Matomo (formerly Piwik), an open source software which enables the statistical analysis of website visits. Matomo uses cookies (text files) which are saved on your computer and which allow us to analyze how you use our website. The website user information generated by the cookies will only be saved on the servers of our IT Department. We use this information to analyze www.eso.org visits and to prepare reports on website activities. These data will not be disclosed to third parties.
On behalf of ESO, Matomo will use this information for the purpose of evaluating your use of the website, compiling reports on website activity and providing other services relating to website activity and internet usage.
Matomo cookies settings:
Additional Third-party cookies on ESO websites: some of our pages display content from external providers, e.g. YouTube.
Such third-party services are outside of ESO control and may, at any time, change their terms of service, use of cookies, etc.
YouTube: Some videos on the ESO website are embedded from ESO’s official YouTube channel. We have enabled YouTube’s privacy-enhanced mode, meaning that no cookies are set unless the user actively clicks on the video to play it. Additionally, in this mode, YouTube does not store any personally identifiable cookie data for embedded video playbacks. For more details, please refer to YouTube’s embedding videos information page.
Cookies can also be classified based on the following elements.
Regarding the domain, there are:
- First-party cookies, set by the website you are currently visiting. They are stored by the same domain that you are browsing and are used to enhance your experience on that site;
- Third-party cookies, set by a domain other than the one you are currently visiting.
As for their duration, cookies can be:
- Browser-session cookies, which are deleted when the user closes the browser;
- Stored cookies, which stay on the user's device for a predetermined period of time.
How to manage cookies
Cookie settings: You can modify your cookie choices for the ESO webpages at any time by clicking on the link Cookie settings at the bottom of any page.
In your browser: If you wish to delete cookies or instruct your browser to delete or block cookies by default, please visit the help pages of your browser:
Please be aware that if you delete or decline cookies, certain functionalities of our website may be not be available and your browsing experience may be affected.
You can set most browsers to prevent any cookies being placed on your device, but you may then have to manually adjust some preferences every time you visit a site/page. And some services and functionalities may not work properly at all (e.g. profile logging-in, shop check out).
Updates to the ESO Cookies Policy
The ESO Cookies Policy may be subject to future updates, which will be made available on this page.
Additional information
For any queries related to cookies, please contact: pdprATesoDOTorg.
As ESO public webpages are managed by our Department of Communication, your questions will be dealt with the support of the said Department.