Süper Masif Karadeliklerin Kökenleri Karanlık Madde Tepkimeli 'Karanlık Yıldızlar' Olabilir

Nat Alianovna

DH Yönetici

3030 Mesaj

Tüm Başarılarını Gör

Literatürdeki bu varsayımsal yıldızlar çok ilginçler ve James Webb Uzay Teleskobu Karanlık Madde Yıldızları hipotezinin test edilmesini sağlayabilir. Prensipte - her normal yıldız gibi hidrojen ve helyumdan oluştuklarının varsayılmasına rağmen - normal maddenin nükleer füzyon süreciyle değil, bileşenlerindeki normal maddeye nazaran inanılmaz cüzi miktarlarda bulunan karanlık madde ve anti karanlık maddenin etkileşimleriyle yanıyorlar. Bu açıdan bu yıldızlara anti (karanlık) madde yıldızları da diyebiliriz çünkü madde anti madde interaksiyonundan güç alıyorlar. Dahası bu haliyle bile bu yıldızlar evrendeki en yoğun karanlık madde toplulukları, ironik şekilde karanlık maddenin ona bu adı kazandıran gayri elektromanyetik niteliğinin aksine madde- anti madde etkileşimlerle erken evrenin muhtemelen en parlak ve en büyük yıldızları arasındalar. Eğer Karanlık Madde Yıldızlarının varsayılan yıldız-benzeri spektrumları galaksiler ve diğer yıldızlardan ayırt edilebilirse varlıklarına dair güçlü bir empirik zemin meydana gelebilir. James Webb'in sağladığı verilere göre erken aşamada şu an üç erken evren objesinin öncül verileri Karanlık Madde Yıldızı spektrum modellerine uyuyor: JADES-GS-z13-0 , JADES-GS-z12-0 , and JADES-GS-z11-0. Ama bunların tam olarak ne olduğunun anlaşılabilmesi için aktarılana göre daha fazla spektroskopik çözünürlük, yani daha fazla görsel derinlik lazım. Bunun için mevcut James Webb teleskobunun misyon için uygun biçimde optimize veya modifiye edilmesini ya da daha uzak bir gelecekte daha güçlü yeni bir uzay teleskobunun fırlatılmasını beklememiz gerekir.

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Introduction
The James Webb Space Telescope (JWST) is poised to revolutionize our understanding of the formation and properties of first luminous objects in the universe. Since beginning to take data, JWST has discovered a surprising number of extremely bright high redshift galaxy candidates [e.g. 1–5], which are difficult to reconcile with expectations from numerical simulations of the universe in the canonical ΛCDM scenario. In this paper we show that some of the JWST high redshift galaxy candidates could instead be Dark Stars (DSs), early stars made almost entirely of hydrogen and helium but powered by dark matter (DM) heating rather than by fusion. Dark stars provide a good match to JWST data, both in terms of their spectra (good fits to JWST photometry) and in that JWST (given its angular resolution) cannot rule out a point source interpretation of many of these candidates.

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Some of the JWST high redshift galaxy candidates could instead be Dark Stars, which are made almost entirely of hydrogen and helium with less than 0.1% of the mass in the form of dark matter. Since they remain cool (without a central hot core), there is no fusion inside them; instead, DM annihilations happen throughout their volume. Dark stars are giant, puffy (∼ 10 AU) and cool (surface temperatures ∼ 10, 000 K) objects. We follow the evolution of dark stars, in thermal and hydrostatic equilibrium, from their inception at ∼ 1M as they accrete mass from their surroundings to become Supermassive Dark Stars (SMDSs), some even reaching masses > 106M and luminosities > 1010M, making them visible to JWST [23, 24]. Once the dark matter runs out and the SMDS dies, it collapses to a black hole; thus dark stars may provide seeds for the supermassive black holes observed throughout the Universe and at early times

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For a more definitive answer, higher quality spectroscopy of the objects will be required. Specifically, as we will show below, the appropriate Helium lines could be smoking guns for dark stars, and could distinguish between, for instance, a galaxy made of Pop III stars and a single SMDS. A Helium-II absorption feature at 1640 ˚A would be characteristic of a hot SMDS [24]. An emission line at the same wavelength would be characteristic of a Pop III galaxy. For all types of SMDSs, the Balmer absorption lines, at rest frame wavelengths λ & 0.35µm can be used to differentiate them from early galaxies, which will typically exhibit emission lines at the same wavelengths

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Dark Stars
As the molecular clouds of hydrogen collapse inside early minihaloes in the process of star formation, the large reservoir of dark matter at the centers of the minihaloes can play an important role. If the DM particles are their own antiparticles, then their annihilation provides a heat source that stops the collapse of the clouds and in fact produces a different type of star, a Dark Star, in thermal and hydrostatic equilibrium. We wish to emphasize that Dark Stars are made almost entirely of ordinary matter (hydrogen and helium) but powered by DM, even though the DM only constitutes less than 0.1% of the DS. We considered two types of DM particles: Weakly Interacting Dark Matter (WIMPs, in most of our papers) and Self Interacting Dark Matter (SIDM). The energy production per unit volume provided by the annihilation of two DM particles is given by: Q = mχn 2 χhσvi = hσviρ 2 χ/mχ, (1) where mχ ∼ 1GeV − 10TeV is the DM mass, nχ is the DM number density, ρχ is the DM energy density. We have used the fact that the DM mass is converted to energy in the annihilation, and we took the standard annihilation cross section (the value that produces the correct DM abundance in the Universe today): hσvi = 3 × 10−26cm3/s. We note that cross sections several orders of magnitude smaller or larger would work equally well; by considering a variety of WIMP masses we can see from Eq.(1) that this is equivalent to considering a variety of cross sections. Three key ingredients are required for the formation of DSs: (1) sufficient DM density, (2) DM annihilation products become trapped inside the star, and (3) the DM heating rate beats the cooling rate of the collapsing cloud. In our previous work we showed that all three criteria can be easily met. The criterion of high DM density can be met in two ways. First, as the hydrogen cloud collapses, it dominates the potential well and pulls in more DM with it. This phenomenon can be well described by adiabatic contraction (AC).1 Since many DM particles are on chaotic or box orbits, the central DM density can be replenished and kept high for millions (to billions) of years. Secondly, once the DM power is depleted, the star starts to collapse, and in the process reaches a high enough density that it is able to capture further DM particles via elastic scattering of the DM with the atoms in the star. We will consider both extended AC and capture in this paper. Once a DS forms of ∼ 1M, we have studied its evolution with two different types of stellar codes: one of which assumes that the DS can be approximated as a polytrope, and the MESA stellar evolution code [30]. In both cases, we find essentially the same results [31]. Because the DS are puffy and cool (surface temperatures ∼ 104K), they are able to accrete the material around them and become very massive (there is not enough ionizing radiation to prevent accretion). We find the equilibrium structure for the stars of a given mass, and then build up the stars one solar mass at a time, always in equilibrium, and find that some of them can become Supermassive Dark Stars (SMDS) that are incredibly massive (> 106M) and bright (> 109L), and the heaviest ones should be visible in JWST. Because they are simultaneously bright, they may look different from competing objects.

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In particular, the JWST Advanced Deep Extragalactic Survey (JADES) has discovered four spectroscopically confirmed Lyman break objects: JADES-GS-z13-0 , JADES-GS-z12-0 , JADES-GS-z12-0 , and JADES-GS-z10-0 [25, 26]. In this paper we will show that three of these four JADES high-z objects are consistent with Supermassive Dark Stars. We find that, with the exception of JADES-GSz10-0 , the photometry of those objects can be modeled by SMDSs Spectra

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We show that each of the following three objects: JADES-GS-z13-0 , JADES-GS-z12-0 , and JADES-GS-z11-0 (at redshifts z ∈ [11, 14]) are consistent with a Supermassive Dark Star interpretation, thus identifying, for the first time, Dark Star candidates.

arxiv.org

Supermassive Dark Star candidates seen by JWST?

https://arxiv.org/abs/2304.01173

https://arxiv.org/pdf/2304.01173.pdf

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Süper Masif Karadeliklerin Kökenleri Karanlık Madde Tepkimeli 'Karanlık Yıldızlar' Olabilir

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