NASA is preparing all 17 science instrument modes for the James Webb Space Telescope (JWST), and while ten are yet to be check-off, we have a moment to review a few that are already to-go.
This week, Webb’s team gave the green signal to the NIRCam grism time series, image time series, NIRISS aperture masking interferometry function, NIRISS wide field slitless spectroscopy & NIRSpec bright object time series.
With that, seven modes are ready to board the James Webb telescope. So get ready for the future of space astronomy.
JWST will zoom in on the first galaxies
A recent NASA blog post introduces MIRI’s Medium Resolution Spectroscopy (MRS) mode and prospect of sharing related technical data. One of the telescope’s most advanced instrument modes, MIRI’s MRS consists of an integral field spectrograph “that simultaneously provides spectral & spatial information for the entire field of view,” said Alvara Labiano of the Centro de Astrobiologica (CAB) and David Law of the Space Telescope Science Institute ( STScI) in the NASA blog post.
“The spectrograph provides 3D ‘data cubes’ in which each pixel in an image contains a unique spectrum,” added Law and Labiano. “Such spectrographs are extremely powerful tools to study the composition & kinematics of astronomical objects because they combine the advantages of traditional imaging & spectroscopy.”
MRS was designed to maintain a resolving power, which is the observed wavelength divided by the smallest detectable wavelength difference, of around 3000. “That’s high enough to resolve important atomic and molecular features in a variety of environment,” Law and Labiano said the post. “At higher redshifts, the MRS will be able to study hydrogen emission from first galaxies.”
Characterizing image quality and spatial alignment for Webb’s MIRI
“At lower redshifts, it will probe the features of molecular hydrocarbons in nearby galaxies and detect the bright spectral fingerprints of elements like oxygen, argon & neon, which can tell us something about the properties of ionized gas in interstellar medium.” added Law & Labiano. “Closer to home, the MRS will produce map spectral features originating from water ice & simple organic molecules in giant planets in our own solar system and in planet-forming disks around other stars.”
When the image quality & spatial alignment of different bands of information are “well characterized,” Webb’s MIRI team will work to calibrate the instrument’s spectroscopic response. This involves several steps, such as narrowing down the right wavelength and spectral resolution in Webb’s 12 fields of view, which will be achieved through observations of “compact emission line objects & diffuse planetary nebulae ejected by dying stars,” Law and Labiano explained.
“We demonstrate the exceptional spectral resolving-power of the MRS with a small segment of a spectrum obtained from recent technical observations of the active galactic nucleus at the core of Seyfert’s galaxy NGC 6552,” scientists said. Once MRS ready, it will play an important role during the “Cycle 1” science programs, which are the first tasks the JWST will execute in the service of genuine space based astronomy. And it’s only a few weeks away.
