This hubble picture shows a supernova called SN 2022aajn in a distant galaxy, which is about 600 million light years away with the unwieldy name WiSea J070815.11+210422.3. However, the blunt, but scientifically descriptive names are not what is important.
It is important that SN 20222aajn is a type -1a supernova, which is also referred to as the standard candle, and this image is part of a critical effort in cosmology.
Standard candles are an important part of the cosmic spacer (CDL). Astronomers use the CDL to determine precise distances to objects at extreme distances. There are different types of standard candles, although type 1A supernovae are considered the most reliable. What do all standard candles have in common?
You have a well -known intrinsic luminosity. This means that in all directions you emit the same amount of energy across all wavelengths. No matter what angle it is measured, it is the same luminosity. Our sun has intrinsic luminosity for clarity.
Astronomers compare the intrinsic luminosity of a standard candle with its apparent or observed brightness. Note the different terms “luminosity” and “brightness”. The brightness depends both on the luminosity of an object and on how this luminosity is reduced by the distance and all matter in between such as dust.
The cosmic distance manager is omnipresent in cosmology and does a good job. However, it still has some problems. The main problem has to do with calibration: How can astronomers determine what the absolute size of a candle is? How can you describe the class of objects called -1a -SN exactly so that you can recognize everyone? And how can you find enough of you in known distances to determine your intrinsic luminosity with extreme accuracy?
The cosmic distance manager begins in parallax, but has its limits. Astronomers rely on standard candles beyond Paralax. Photo credits: by ESA/Hubble, CC from 4.0, https://commons.wikimedia.org/w/index.php?curid=49212250
This Hubble picture is part of the effort. As part of an observation program, the Hubble 100 Type -1a Supernovae is observed in order to better calibrate our understanding of standard candles and their distances.
The name of the program gives a good idea of its goal. It says “Reduction of Type -Ia -Supernova distortions by separating redness and intrinsic color”. Prof. Ryan Foley from the University of California in Santa Cruz is the main researcher.
If type 1a supernova were exploded in a universe without dust, the work of the astronomers would be simplified. But of course they don't. They explode in galaxies with their own dust. There can also be a lot of intergalactic dust between us and removed SN. Everything that has dust from Supernova and makes its intrinsic luminosity more difficult to determine.
Type -1a Supernovae appear in binary systems in which a star is a massive white dwarf. When his companion ages and swells, the white dwarf pulls material away from the companion to his surface. Finally, the white dwarf explodes. Photo credits: from NASA, ESA and A. Feild (STSCI); Vectorization of Chris? – http://hubblesite.org/newscenter/areleases/star/supernova/2004/34/image/d/, cc from 3.0, https://commons.wikimedia.org/w/index.php?curid= = 8666262
In observations, the redness of the dust is tangled by reducing red shift. Dust in the intergalactic medium is about as large as the wavelength of blue light. The dust absorbs and sprinkles the light from remote objects, which makes its light more red to the point in time when it reaches us. Professor Foley's observation program is an effort to “remove” intergalactic dust from our observations.
“Precise distance measurements and impartial cosmological restrictions from supernovaentype-supernovae (SNE IA) rely on a proper correction for the redness of the tavern of the tavern, which can weaken the observed SN brightness,” write foley and his fellow research. To avoid this, astronomers use a so -called “Reddening Act”. “A correction is made by comparing the observed and intrinsic color and using a reduction law to determine the extinction,” they write.
However, reduction laws are difficult to work. It's a delicate matter. “This procedure is not trivial, since the intrinsic color of an SN correlates with its luminosity in a way that can be almost distinguished from the effects of dusting in optical wavelengths,” Foey writes in the description of the observation campaign.
Astronomers use a somewhat simplified way to determine how red is a distant supernova by treating the redness from both dust and distance. “The current standard for measuring SN distances treats both idiosyncratic relationships as a single SN color law,” explains Foley. However, this leads to a distortion in measurements, since both causes probably do not contribute equally and uniformly to reddening.
“This problem is currently the greatest systematic uncertainty of SN cosmology and prevent future cosmological experiments from being achieved,” explains Foley. He also says that the mistake can be up to 6%. This is a lot in measuring objects that are hundreds of million light years away, and even much further.
How can astronomers solve this problem? By receiving better data and more of it. This is the motivation for foleys campaign that tries to avoid the problem by observing several wavelengths across the lifting.
“The way to break the degradation between SN color and dusting is to expand the observations to UV and NIR, whereby the dust and the intrinsic color dominate the observed color,” says the description of the observation program.
The researchers will try to avoid the problem of SN cosmology by examining the Hubble 100 Type Ia Supernovae in seven wavelength gangs from ultraviolet to close infrared. The leading picture is a combination of image data from four infrared wave lengths, since IR is easier to run through dust than UV or visible light. The researchers then compare the brightness of the SNE over the wavelengths and disguise the distance effect of the dusting effect.
We are used to the “Eye Candy” pictures of the hubbles that have been carrying websites and magazines for decades. You have changed our understanding of nature. But in the purely scientific side of the telescope is part of its real transformative power.
An exact cosmic spacer is an essential part of cosmology. By supporting scientists to determine the exact distances to standard candles, the Hubble helps to develop a more cosmic spacer and to pave the way for a better understanding of the universe.
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