Хятадын FAST радио телескопоор хийсэн судалгаагаар одны ажиглагдах шинж тэмдэггүй, асар их хэмжээний устөрөгч агуулсан J1351+0039 нэртэй биетийг олж тогтоожээ.
Хятадын Үндэсний одон орон судлалын төвийн судлаач Жин-Лонг Шю тэргүүтэй баг 2026 оны долоо болон наймдугаар сард J1351+0039 биетэд гурван удаагийн ажиглалт хийсэн байна. Энэхүү биет нь Нарнаас 500,000 дахин их масстай саармаг устөрөгчөөс бүрдэх бөгөөд нийт масс нь 130 сая нарны масстай тэнцэхээр тооцоологджээ. Гэвч DESI Legacy Survey-ийн гүнзгийрүүлсэн зургуудад тус үүлтэй холбоотой ямар нэгэн од бүртгэгдээгүй байна.
Эрдэмтдийн таамаглаж буйгаар уг биет нь “иончлолын хязгаарлагдмал устөрөгчийн үүл” (RELHIC) байж болох юм. Сансрын иончлолын үлдэгдэл хэт ягаан туяа нь хийг хэт халуун, сийрэг байлгаснаар од үүсэх явцыг саатуулдаг байна. Уг үүл нь эргэлтийн хөдөлгөөнөөс илүү хийн даралтаар тогтож буй нь түүнийг ердийн галактикуудаас ялгаатай болохыг харуулж байна.
Одоогийн байдлаар уг биетийг жинхэнэ утгаараа одгүй харанхуй галактик гэж батлах боломжгүй байна. Оптик телескопуудын хүчин чадлын хязгаарлагдмал байдлаас шалтгаалан маш бүдэг оддын бөөгнөрөл ажиглагдаагүй байх магадлалтай юм. Энэхүү таамаглалыг батлахын тулд James Webb эсвэл Hubble сансрын дуран авайгаар нэмэлт судалгаа хийх шаардлагатай гэж судлаачид үзэж байна.
Дэлгэрэнгүйг эх сурвалжаас харах
↓Эх сурвалжийг нээх ↓
Astronomers have identified an isolated cloud of hydrogen that could be a galaxy with no stars. Discovered using China’s FAST radio telescope, the object, known as J1351+0039, contains nearly 500,000 times the Sun’s mass in neutral hydrogen but shows no visible stellar population. Researchers consider it one of the strongest candidates yet for an isolated dark galaxy.
Scientists are now asking how galaxies are built, and why some clumps of matter stay completely dark. According to the leading cosmological model, ΛCDM, tiny blobs of dark matter formed first and slowly merged into bigger ones. But some of the smallest blobs may simply never have had what it takes to form stars.
These potentially starless systems are known as reionization-limited H I clouds (RELHICs). Ultraviolet radiation left over from cosmic reionization can keep their gas too warm and diffuse to collapse into stars. Since they emit little or no visible light, astronomers must search for them through the 21-centimeter radio signal produced by neutral hydrogen.
A Lonely Cloud of Hydrogen
The object was detected during a survey conducted with the Five-hundred-meter Aperture Spherical radio Telescope (FAST), which can identify neutral hydrogen clouds that optical telescopes cannot readily observe.
As explained in the research paper posted on arXiv on September 24, 2026, a team led by Jin-Long Xu of the National Astronomical Observatories of China carried out three observations of J1351+0039 between July and August 2026. The measurements revealed approximately 500,000 solar masses of neutral hydrogen, while the system’s estimated total mass reaches 130 million solar masses. Yet deep images from the DESI Legacy Survey showed no detectable stars associated with the cloud.
Its surroundings are equally unusual. Researchers found no large galaxies within a projected angular separation of 1.5 degrees, equivalent to less than 100 kiloparsecs at the object’s distance, and a velocity difference below 250 kilometers per second. There were also no gaseous bridges, comet-like tails, or nearby companions suggesting that the hydrogen had been pulled away from another galaxy.
Gas That Moves Differently
In typical disk galaxies, gas follows organized rotational motion. J1351+0039 behaves differently: its measured rotational velocity is only 4.2 kilometers per second, while its random gas motions reach approximately 11.6 kilometers per second. That difference indicates a system supported mainly by gas pressure rather than rotation.
“The pressure-supported nature therefore suggests that J1351+0039 may be a RELHIC that has gradually acquired angular momentum,” the researchers explain in their paper.
The cloud has a roughly rounded appearance, a positive velocity, and a gas temperature of approximately 10,000 Kelvin. This temperature is consistent with gas maintained in equilibrium by the surrounding ultraviolet radiation background.
In such conditions, hydrogen may remain too warm to become sufficiently dense for star formation. The combination of weak rotation, random gas movements, and its physical structure is consistent with theoretical descriptions of starless, gas-bearing dark matter halos.
Is It Really a Dark Galaxy?
Despite the evidence, astronomers cannot yet establish whether J1351+0039 has truly never formed stars. The main uncertainty comes from the limits of optical observations, as an extremely faint stellar population could exist without appearing in current survey images.
As reported by Phys.org, the researchers identify two possible explanations: the cloud could be a genuine RELHIC, or it could be an ultra-faint dwarf galaxy whose stars remain undetected. Observations with the James Webb Space Telescope or Hubble Space Telescope may be required to investigate the possibility of a hidden stellar population.
The distinction is significant because only one RELHIC has been observationally confirmed, while two other promising candidates have been identified. For J1351+0039, the absence of nearby massive galaxies also reduces the complications associated with tidal interactions.
The researchers describe it as the most compelling isolated RELHIC candidate identified so far. Whether it is completely starless remains uncertain, but its hydrogen content, internal motions, and isolation already distinguish it from previously studied systems.
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