Himiko (Lyman-alpha blob)

Himiko is a large gas cloud found at redshift of z=6.6 that predates similar Lyman-alpha blobs. At time of discovery, researchers said it "may represent the most massive object ever discovered in the early universe."^[1] It is located in Cetus at redshift z=6.595, about 12.9 billion light years from Earth, or about 7022750000000000000♠75×10²¹ miles (7023122000000000000♠122×10²¹ kilometers).

Characteristics

This nebular gas cloud is thought to be a protogalaxy, caught in the act of formation. There have been no spectroscopic signatures of anything other than hydrogen or helium, and its luminance cannot be ascribed to gravitational lensing, black holes or exterior excitation. The lack of any chemical signatures other than hydrogen and helium illustrate the extreme primitiveness of the object, and early enough so as not to be polluted by carbon signatures from young stars.^[2]

Size

It is 55,000 light years across (half the diameter of our galaxy), and at the time of discovery, said to "hold more than 10 times as much mass as the next largest object found in the early universe, or roughly the equivalent mass of 40 billion Suns".^[1]

Discovery

Masami Ouchi, a researcher at the Carnegie Institution in Pasadena, California, stated "I have never heard about any [similar] objects that could be resolved at this distance...[i]t's kind of record-breaking."

Name

The object was named by a Japanese scientist after a 3rd-century Japanese shaman queen Himiko.^[1][3]

References

• SIMBAD, "NAME Himiko" (accessed 12 April 2010)

Literature

• Ouchi, Masami; et al. (May 2009). "Discovery of a giant Lyα Emitter near the Reionization Epoch". The Astrophysical Journal (696): 1164–1175. arXiv:0807.4174v2. Bibcode:2009ApJ...696.1164O. doi:10.1088/0004-637X/696/2/1164. 

Citations

External links

• "Mysterious Space Blob Discovered at Cosmic Dawn" (Press release). Carnegie Institute for Science. April 22, 2009. Retrieved April 30, 2011. 

Coordinates: 02^h 17^m 57.563^s, −05° 08′ 44.45″