Anuncio
Primeras "franjas interferométricas" de ALMA en Chajnantor
16 de Noviembre de 2009
Un equipo de astrónomos e ingenieros del Atacama Large Millimeter/submillimeter Array (ALMA) han realizado las primeras mediciones interferométricas en señales de radio –llamadas “franjas”- de una fuente astronómica, desde el alto sitio del observatorio ubicado a 5.000 metros en Chajnantor. Ello constituye un importante paso técnico para ALMA, que implicó el uso de un equipo de producción completo, incluyendo dos de las antenas de 12 metros de diámetro y sofisticados sistemas electrónicos para recibir y combinar las señales. Esta es la primera vez que todas estas piezas complejas, casi todas las cuales se encuentran a la vanguardia tecnológica, se han utilizado juntas como un solo sistema.
Las antenas fueron trasladadas hacia el Llano de Chajnantor el 16 y 17 de octubre pasado. En las semanas siguientes, el sistema fue conectado y testeado. Finalmente, se midieron las “franjas”, efecto visto cuando las señales recibidas por un par de antenas se combinan sincronizadamente. Para lograrlo, usaron una variedad de conocidos objetos astronómicos, que incluyeron la nube molecular Orión y el quásar 3C84. El equipo desarrolló experimentos para determinar exactamente la distancia entre las antenas (la “línea base”), que fue calculada en 159.8331 metros con una precisión de medio milímetro, y la diferencia de tiempo (el “retraso”) que le tomó a las señales viajar desde el edificio central, calculado en 1959.642 nanosegundos con una precisión de dos centésimas de nanosegundo. Al mismo tiempo fueron sometidos a prueba los equipos y conexiones necesarias para la operación a longitudes de onda menores. Las mediciones de las franjas del quasar 3C454.3 marcaron la primera vez en que los equipos de ALMA han detectado franjas a longitudes de onda de menos de 1mm, por lo que ALMA es ahora verdaderamente un telescopio “submilimétrico”, así como milimétrico.
Para generar las franjas, que constituyen el primer paso hacia la obtención de imágenes detalladas de los objetos astronómicos que están siendo observados, las señales son recibidas y procesadas por los sistemas de detección y electrónica de la antena, y luego transmitidas por fibra óptica al Edificio de Operaciones Técnicas de ALMA, donde son combinadas y almacenadas en los archivos.
El equipo está ahora esperando realizar los próximos pasos en el proceso –la suma de una tercera antena que les permitirá verificar mejor el software y hardware, obteniendo un “cierre de fase”, una importante capacidad que requiere de al menos tres antenas, para eliminar los errores de fase en la señal producidos por los instrumentos y la atmósfera.
El Atacama Large Millimeter/submillimeter Array (ALMA), instalación astronómica internacional, es una alianza entre Europa, Norteamérica y Asia Oriental en cooperación con la República de Chile.
Enlaces
Contactos
Douglas Pierce-Price
ESO, Garching, Alemania
Tel: +49-89-3200-6759
E-mail: dpiercep@eso.org
Sobre el anuncio
| Identificador: | ann0934 |
Imágenes
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.