Since the James Webb Space Telescope (JWST), astronomers have observed galaxies more than 13 billion years ago. During this time, known as the “cosmic dark age”, the first stars and galaxies formed between 200 million and 1 billion years after the big bang. Unfortunately, light from this time was limited to the relics radiation caused by the Big Bang – the cosmic microwave background (CMB) – and photons caused by the tironization of neutral hydrogen by star radiation.
Earlier observatories, such as the venerable Hubble and Spitzer world space telescopes, were unable to observe galaxies during this period due to their limited infrared (IR) sensitivity. Thanks to the advanced IR instruments, coronographers and the heat shield from WebB, the curtain is finally pulled in the dark age. In a recently carried out study, an international team of scientists searched the archive data of WebB from Galaxies, which only existed a few hundred million years after the Big Bang, and pushed WebB to the limits of its imaginary skills.
The study was headed by Marco Castellano, a researcher from the National Institute of Astrophysics' Observatorio Astronomico di Roma (Inaf-Oar). He was JOINED by Colleagues from the Inaf, The National Optical-Infrared Astronomy Research Laboratory, The Instituto de Astrofísica de Andalucía (IAA-CSIC), The Harvard & Smithsonian for Astrophysics (CFA), The Space Science Institute (STSCI), NASA Goddard Space Flight Center, and Multiple Universities and Institutes.
Since WebB was put into operation for the first time, galaxies that existed more than 13 billion years ago. Pictures of some of these early galaxies were taken into the Esos (Early Release observations by WebB), which contained “Little Red Dots”, which turned out to be early active galactic cores (aka. Quasare). In front of the webb, astronomers could fix galaxies with a red shift of ~ 10 (~ 500 million years after the big bang), but with much low sensitivity.
But as Castellano said today by e -mail to Universe, the greater sensitivity of WebB has opened a new window in the first phases of galaxy formation and development:
“YWST has discovered dozens of sources with higher red shifts up to Z-14 (the current record holder, which corresponds to ~ 300 Myr according to the BB). Myr according to the BB and the large number of weak AGN in the first billion years.”
The number of galaxies found during this time and their obvious brightness surprised the astronomers because they were “tension” with established cosmological models. The same applies to the super massive black holes (SMBHS) observed during this period, which were larger than cosmological models that were predicted. In both cases, these models indicate that there was not enough time because the big bang for so many bright galaxies form or SMBHS are so big. The previous statement, said Castellano, is the focus of his research:
“Since the first observations, JWST has found a number of galaxies in Z> 9 with light UV emissions, which is much higher than through theoretical models or on the basis of previous observations. In the past 3 years, several theoretical attempts to explain these” surpluses “of light galaxies have been either on, e.g. Super-massive black holes, etc. As the previously examined to test the predictions of these theoretical models.
According to their study, the team consulted JWST and HST photometric measurements from the Astrodeep-JWST catalogs and analyzed the seven surveys from which it includes. This included the Cosmic Evolution Early Release Science Survey (CEERS), Fields, which from the Great Observatories Origins Deep Survey-North (Waren-N) and War Süd surveys, First Reonication Epoch Spectroscopical Complete Observations (FRESCO), the next generation Deep Experactalical Itrospocy (NGDEEP) campaign, candels, glass, glass, YEW and more.
As already mentioned, the team searched these photometric data sources to galaxies with red-shift values of Z = 15-30. The candidates they selected were selected on the basis of the form of their spectral learning distribution and lyman breaks. This latter technology includes the observation of high -red -reducing galaxies by near infrared and ultraviolet (UV) filter, since the radiation from these galaxies is almost completely absorbed by the neutral gas that surrounds it. As Castellano explained, this presented many challenges:
“On the one hand, objects are weaker and are detected in a smaller number of photometric gangs, which makes the restrictions less significant for the shape of their spectrum. On the other hand, it becomes obvious that there is a higher risk of contamination of contaminants with lower reddocks. Try the problem. Fotometry photometer information is the problem.
“These are typically objects whose spectral energy distribution imitates from Z> 15 galaxies because they are very red, i.e. their emission increases for longer than 2 micrometers in wave lengths, since their star light is extremely weakened by dust, or because they are dominated by old star populations. In some cases, the muxardous cases are identified. Emission with extremely strong emissions lines that have observed in some of the Increase filter. “
At the moment, astronomers were only able to identify a few candidate galaxies with red -shift values of Z = 15 or higher. This is despite the fact that the UV rast frame emissions of these galaxies are within the spectral cover of the near infrared camera from WebB (Nircam). Nevertheless, breaking the Z = 15 barrier is of essential importance to learn galaxy development during the early universe when the first stars and galaxies formed. This information will help fix the current tensions between theoretical models and observations.
In total, the team selected 10 objects from the Astrodep-JWST catalogs, the colors of which were compatible with a red shift of z = 15 to 20. However, as Castellano explained, the analysis of these sources has again shown that studying objects on these red shifts is extremely difficult. “[I]T is true that they are credible candidates with high red shift, but they are also compatible with the expected colors of rare galaxy populations in lower red shifts, “he said.
For example, one of these candidates has already been observed with the Near Infrared spectrometer (NIRSPEC) from WebB as part of the prism era of rionalization of Candels (capers). This galaxy has a high level of stars and a red shift of Z = 6.56 (~ 13.2 billion years), but is weakened by dust, which it appears. However, the remaining candidates in their study remain potential Z ~ 15-20 candidates who deserve a further study:
[I]F we assume that you are all galaxies at Z> 15, the effects are extremely interesting. Their number would mean a wealth of bright galaxies 2-300 Myr after the Big Bang, which is higher than predicted by theoretical models. In fact, the spectroscopic confirmation of only a small part of these objects would imply a significant voltage with theoretical predictions. “
In addition, the team's study could have an impact on the examination of dusty galaxies that existed a little more than 13 billion years ago. Like extremely top -class galaxies, galax9es are poorly known at Z = 4 to 7 (12.5 to 13.3 billion years). These consist of both dusty star formation foods and passive galaxies with a low mass, which are rare compared to light UV and low damping galaxies from this era. Further studies by these candidates could do much more about this early time in cosmic history.
In the meantime, Castellano and his team emphasize the need for follow -up examinations of galaxies that could have red displacement values of Z = 15 or more:
It is crucial to carry out the spectroscopic follow-up of objects that were selected as potential Z> 15 galaxies. Confirmation as a real red -reducing galaxies would have a significant impact on our understanding of the earliest phases of galaxy development. If we find out that you are all “interlopers” of the red-delayed “intermediate”, we will be able to understand the poorly known populations of dusty and passive galaxies in intermediate speaking, which we can only discover and investigate thanks to JWST.
The preliminary print of your paper was recently published online and is checked for publication in the magazine Astronomy & Astrophysics.
Further reading: arxiv.org
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