www.sron.nl/122-hifi2/hifi.html

27-01-2016
a-second-earth-revealed-in-nemo

"A Second Earth" revealed in NEMO

Wednesday 27 January 2016 the exhibit "A Second Earth" was officially presented in Science Center NEMO. SRON sponsors this exhibit, which is part of the exhibition 'The Search for Life'.        Read more (in dutch)
26-01-2016
sto-2-loses-race-against-time-at-antarctica

STO-2 loses race against time at Antarctica

The balloon mission STO-2 has not been launched from the South Pole. The balloon, which is equiped with Dutch detectors, was scheduled this January to make a circular flight over Antarctica and to observe the universe at an altitude of 40 km. But due to bad weather the balloon could not be launched in time to take advantage of the polar anticyclone, which causes air to slowly circulate in a counterclockwise pattern. NASA has now postponed the mission to the next Antarctic summer at the end of 2016/beginning of 2017.         More
03-12-2015
lisa-pathfinder-en-route-to-gravitational-wave-demonstration

LISA Pathfinder en route to gravitational wave demonstration

  ESA's LISA Pathfinder lifted off earlier today on a Vega rocket from Europe's spaceport in Kourou, French Guiana, on its way to demonstrate technology for observing gravitational waves from space. Gravitational waves are ripples in the fabric of spacetime, predicted a century ago by Albert Einstein's General Theory of Relativity, published on 2 December 1915.         More
30-11-2015
in-search-of-the-biggest-bangs-after-the-big-bang

In search of the biggest bangs after the Big Bang

On 2 December 2015 the European Space Agency ESA will launch the satellite LISA Pathfinder, an important technology demonstration mission for measuring the gravitational waves in space predicted by Einstein. With gravitational waves scientists expect to be able to make new discoveries about objects such as compact binary stars and merging supermassive black holes, which are responsible for the biggest bangs after the Big Bang. And completely new fundamental physics is also on the horizon.         More
26-11-2015
black-holes-behave-like-matryoshka-dolls

Black holes behave like Matryoshka dolls

  An international team of astrophysicists has established that supermassive black holes behave like small stellar black holes. They made their discovery by observing a supermassive black hole that has torn apart a star, causing a surge of gas towards it. Normally such a change in the gas flow takes too long to detect. But this time the transition from a steady flow to a surge of gas happened abruptly, enabling the researchers to detect a jet blasting from the supermassive black hole. This neatly fits the pattern found near small black holes. The results appear  in Science today.         More

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Summary

HIFI's superb spectral resolution coupled with its ability to observe thousands of molecular, atomic and ionic lines at submillimeter wavelengths make it the instrument of choice to address many of the key  questions in modern astrophysics related to the cyclic interaction of stars and the interstellar medium:
  1. HIFI will probe the physics, kinematics and energetics of star forming regions through their cooling lines, including H2O, the major coolant.
  2. HIFI will survey the molecular inventory of such diverse regions as shocked molecular clouds, dense Photon-Dominated Regions (PDRs), diffuse atomic clouds, Hot Cores and proto-planetary disks around newly formed stars, winds from dying stars and toroids interacting with AGN engines.
  3. HIFI is uniquely suited to search for low-lying ro-vibrational transitions of complex species such as PAHs and, thus, to investigate the origin and evolution of the molecular universe.
  4. HIFI can provide the out-gassing rate of comets through H2O rotational lines and determine the vertical distribution of H2O in the giant planets and on Mars.
  5. HIFI can measure the mass-loss history of stars which, rather than nuclear burning, regulates stellar evolution after the main sequence, and dominates the gas and dust mass balance of the ISM.
  6. HIFI will measure the FIR line spectrum of nearby galaxies as templates for distant, possibly primordial galaxies.

The main reason to build HIFI was because the above sketched science cannot be done from the ground, since atmospheric water lines block all radiation coming from space. On the right plots are given of the atmospheric transmission.

HIFI is optimised to address the astronomical key questions given above. All of these require high spectral resolving powers and sensitivity. Combining the high spectral resolving power of the radio heterodyne technique with quantum-noise limited detection from superconductor physics and state-of-the-art microwave technology, has made it possible to develop an instrument with a continuous frequency coverage from 480 to 1250 GHz in five bands, plus a sixth band providing coverage for 1410-1910 GHz at an unrivalled spectral resolution and ultimate sensitivity. This instrument is able to perform rapid and complecte spectral line surveys with resolving powers from 103 up to 107 (300 - 0.03 km/s) and deep line observations.

HIFI Band

1

2

3

4

5

6

Coverage (GHz)

480-
640

640-
800

800-
960

960-
1120

1120-
1250

1410-
1910

Half Power
Beamwidth
(arcsec)

39

30

25

21

19

13

Rec. Noise
(DSB) in K
Baseline values

110

145

175

210

370

800