The merging galaxy system Arp 220 from ALMA and Hubble
Band 5 ALMA receiver
One of the Band 5 receivers for ALMA
One of the Band 5 receivers for ALMA
New receivers improve ALMA’s ability to search for water in the Universe
The Atacama Large
Millimeter/submillimeter Array (ALMA) in Chile has begun observing in a
new range of the electromagnetic spectrum. This has been made possible
thanks to new receivers installed at the telescope’s antennas, which can
detect radio waves with wavelengths from 1.4 to 1.8 millimetres — a
range previously untapped by ALMA. This upgrade allows astronomers to
detect faint signals of water in the nearby Universe.
ALMA observes radio waves from the Universe, at the low-energy end of the electromagnetic spectrum.
With the newly installed Band 5 receivers, ALMA has now opened its eyes
to a whole new section of this radio spectrum, creating exciting new
observational possibilities.
The European ALMA Programme Scientist, Leonardo Testi, explains the significance:
“The new receivers will make it much easier to detect water, a
prerequisite for life as we know it, in our Solar System and in more
distant regions of our galaxy and beyond. They will also allow ALMA to
search for ionised carbon in the primordial Universe.”
It is ALMA’s unique location, 5000 metres up on the barren Chajnantor
plateau in Chile, that makes such an observation possible in the first
place. As water is also present in Earth’s atmosphere, observatories in
less elevated and less arid environments have much more difficulty
identifying the origin of the emission coming from space. ALMA’s great
sensitivity and high angular resolution mean that even faint signals of
water in the local Universe can now be imaged at this wavelength [1].
The Band 5 receiver, which was developed by the Group for Advanced Receiver Development (GARD) at Onsala Space Observatory, Chalmers University of Technology, Sweden, has already been tested at the APEX telescope in the SEPIA instrument. These observations were also vital to help select suitable targets for the first receiver tests with ALMA.
The first production receivers were built and delivered to ALMA in the first half of 2015 by a consortium consisting of the Netherlands Research School for Astronomy (NOVA) and GARD in partnership with the National Radio Astronomy Observatory
(NRAO), which contributed the local oscillator to the project. The
receivers are now installed and being prepared for use by the community
of astronomers.
To test the newly installed receivers observations were made of several objects including the colliding galaxies Arp 220,
a massive region of star formation close to the centre of the Milky
Way, and also a dusty red supergiant star approaching the supernova
explosion that will end its life [2].
To process the data and check its quality, astronomers, along with technical specialists from ESO and the European ALMA Regional Centre (ARC) network, gathered at the Onsala Space Observatory in Sweden, for a "Band 5 Busy Week" hosted by the Nordic ARC node [3]. The final results have just been made freely available to the astronomical community worldwide.
Team member Robert Laing at ESO is optimistic about the prospects for ALMA Band 5 observations: “It's
very exciting to see these first results from ALMA Band 5 using a
limited set of antennas. In the future, the high sensitivity and angular
resolution of the full ALMA array will allow us to make detailed
studies of water in a wide range of objects including forming and
evolved stars, the interstellar medium and regions close to supermassive
black holes.”
Notes
[1] A key spectral signature of water lies in this expanded range — at a wavelength of 1.64 millimetres.
[2] The observations were performed and made possible by the ALMA Extension of Capabilities team in Chile.
[3] The ESO Band 5 Science
Verification team includes: Elizabeth Humphreys, Tony Mroczkowski,
Robert Laing, Katharina Immer, Hau-Yu (Baobab) Liu, Andy Biggs, Gianni
Marconi and Leonardo Testi. The team working on processing the data
included: Tobia Carozzi, Simon Casey, Sabine König, Ana Lopez-Sepulcre,
Matthias Maercker, Iván Martí-Vidal, Lydia Moser, Sebastien Muller,
Anita Richards, Daniel Tafoya and Wouter Vlemmings.
More Information
The Atacama Large Millimeter/submillimeter Array (ALMA), an
international astronomy facility, is a partnership of ESO, the U.S.
National Science Foundation (NSF) and the National Institutes of Natural
Sciences (NINS) of Japan in cooperation with the Republic of Chile.
ALMA is funded by ESO on behalf of its Member States, by NSF in
cooperation with the National Research Council of Canada (NRC) and the
National Science Council of Taiwan (NSC) and by NINS in cooperation with
the Academia Sinica (AS) in Taiwan and the Korea Astronomy and Space
Science Institute (KASI).
ALMA construction and operations are led by ESO on behalf
of its Member States; by the National Radio Astronomy Observatory
(NRAO), managed by Associated Universities, Inc. (AUI), on behalf of
North America; and by the National Astronomical Observatory of Japan
(NAOJ) on behalf of East Asia. The Joint ALMA Observatory (JAO) provides
the unified leadership and management of the construction,
commissioning and operation of ALMA.
ESO is the foremost intergovernmental astronomy
organisation in Europe and the world’s most productive ground-based
astronomical observatory by far. It is supported by 16 countries:
Austria, Belgium, Brazil, the Czech Republic, Denmark, France, Finland,
Germany, Italy, the Netherlands, Poland, Portugal, Spain, Sweden,
Switzerland and the United Kingdom, along with the host state of Chile.
ESO carries out an ambitious programme focused on the design,
construction and operation of powerful ground-based observing facilities
enabling astronomers to make important scientific discoveries. ESO also
plays a leading role in promoting and organising cooperation in
astronomical research. ESO operates three unique world-class observing
sites in Chile: La Silla, Paranal and Chajnantor. At Paranal, ESO
operates the Very Large Telescope, the world’s most advanced
visible-light astronomical observatory and two survey telescopes. VISTA
works in the infrared and is the world’s largest survey telescope and
the VLT Survey Telescope is the largest telescope designed to
exclusively survey the skies in visible light. ESO is a major partner in
ALMA, the largest astronomical project in existence. And on Cerro
Armazones, close to Paranal, ESO is building the 39-metre European
Extremely Large Telescope, the E-ELT, which will become “the world’s
biggest eye on the sky”.
Links
Contacts
Leonardo Testi
European ALMA Programme Scientist, ESO
Garching bei München, Germany
Tel: +49 89 3200 6541
Email: ltesti@eso.org
Robert Laing
ESO ALMA Scientist
Garching bei München, Germany
Tel: +49 89 3200 6625
Email: rlaing@eso.org
Richard Hook
ESO Public Information Officer
Garching bei München, Germany
Tel: +49 89 3200 6655
Cell: +49 151 1537 3591
Email: rhook@eso.org
Links
Contacts
Leonardo Testi
European ALMA Programme Scientist, ESO
Garching bei München, Germany
Tel: +49 89 3200 6541
Email: ltesti@eso.org
Robert Laing
ESO ALMA Scientist
Garching bei München, Germany
Tel: +49 89 3200 6625
Email: rlaing@eso.org
Richard Hook
ESO Public Information Officer
Garching bei München, Germany
Tel: +49 89 3200 6655
Cell: +49 151 1537 3591
Email: rhook@eso.org
Source: ESO
