Astronomers have been so eager to use the new telescope that they have gotten a little ahead of themselves After the first batches of data were released, many began to analyse them and quickly post their results on the preprint server, but are now having to revise their results. When the first data were made available, the telescope's detectors weren't perfect, but that didn't stop some people from being excited.
Many of the exciting early results, such as the discovery of a number of candidates for the most distant galaxy ever spotted, don't seem to have been changed by the revisions. Astronomers are having to think about the limitations of early data from the telescope.
Castellano is an astronomer at the Italian National Institute of Astrophysics in Rome. Illingworth is an astronomer at the University of California Santa Cruz. The astronomer at the University of California, Los Angeles says that nobody expected this to be as big of an issue as it is.
Calibration is difficult for projects that need to accurately measure the brightness of astronomy objects. Astronomers have been cobbling together solutions so that they can continue their work. The Space Telescope Science Institute (STScI) in Baltimore, Maryland, which operates the telescope, is expected to make the next update to the calibrations. The update will shrink the error bars from tens of percentage points to just a few. Calibration efforts will improve data accuracy over time.
The initial calibrations to the telescope were rough, according to Jane Rigby, operations project scientist for the telescope at NASA. The issue stems from the fact that the details of the new telescope are being worked out. The community hasn't had a brand-new telescope in space in a long time.
It wasn't going to be perfect right out of the box and we knew that.
Calibration of all telescopes is necessary. This can be accomplished by observing a well-known star such as Vega. Astronomers look at the data being collected by the telescope's various instruments and compare them with the data from other telescopes and of laboratory standards.
One of the telescope's main instruments, the NearInfrared Camera, is at the center of a controversy. In the six months after the launch, researchers worked to calibrate the NIR cam. They only had enough time to point it at one or two calibration stars, and to take data using just one of NIRCAM's ten detector. Calibrations for the other nine detectors were estimated by them. There was a problem at that location. Each detector will have its own quirks.
Several non-peer-reviewed papers appeared on the arXiv preprint server within days of the first data release. The brightness of distant objects was measured with the help of a telescope. An updated set of calibrations was released by theSTScI on July 29th.
Nathan Adams, an astronomer at the University of Manchester, UK, pointed out the problem in a 9 August update to a preprint they had posted in July. It was a bit of a question for those who had written a paper within the first couple of weeks.
To standardize all the measurements, theSTScI is working through a detailed plan to point the telescope at several types of stars, and observe them with every detector in every mode. Karl Gordon is an astronomer at theSTScI and he says it takes a while.
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Astronomers reworked manuscripts that described distant galaxies based on data from the telescope. Adams said that everyone had a second look and it wasn't as bad as they thought. The most exciting candidates still seem to be close to the original estimates. Preliminary studies that draw conclusions about the early Universe by comparing large numbers of faint galaxies may not stand the test of time. Other fields of research, such as planetary studies, are not affected as much because they don't depend on the initial brightness measurement.
Gabriel Brammer, an astronomer at the University of Copenhagen, says that the observatory is so new and young that they have come to realize how much data processing is going on.
Astronomers will get more confident in their conclusions as they sort out the calibration. When we have more information, I would advise people to proceed with caution. It is simply, 'Proceed at your own risk.'
The article was published on September 28th, 2022.
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