In infrared astronomy, the J band refers to an atmospheric transmission window (1.1 to 1.4 μm) centred on 1.25 micrometres (in the near-infrared).
Betelgeuse is the brightest near-IR source in the sky with a J band magnitude of −2.99. The next brightest stars in the J band are Antares (−2.7), R Doradus (−2.6), Arcturus (−2.2), and Aldebaran (−2.1). In the J band Sirius is the 9th brightest star.
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HUDF-JD2 (UDF 033238.7 -274839.8 or BBG 3179) is a distant, massive, post-starburst galaxythat was discovered with the Hubble Ultra Deep Field (HUDF) image. It was the most distant galaxy identified in the HUDF, in 2005. It is located at 03 32 38.7268 −27° 48′ 39.885″ in the constellation of Fornax.
In a 2005 search for very red galaxies in the HUDF that were not detected at wavelengths shorter than the near-infrared J band, two objects were detected. The second, initially designated UDF033238.7-274839.8, displayed a high redshift and showed characteristics of a post-starburst galaxy. The derived photometric redshift yielded z approximately equal to 6.5, which indicates it is most likely being viewed from a time when the Universe was only 830 million years old. The estimated bolometric luminosity of this galaxy is a trillion times the solar luminosity (the luminosity of the Sun) and it has a mass of approximately 600 billion solar masses.
The Two Micron All-Sky Survey (2MASS) was an astronomical survey of the whole sky in infrared light. It took place between 1997 and 2001, in two different locations: at the U.S. Fred Lawrence Whipple Observatory on Mount Hopkins, Arizona, and at the Cerro Tololo Inter-American Observatory in Chile, each using a 1.3-meter telescope for the Northern and Southern Hemisphere, respectively. It was conducted in the short-wavelength infrared at three distinct frequency bands (J, H, and K) near 2 micrometres, from which the photometric survey with its HgCdTe detectors derives its name.
2MASS produced an astronomical catalog with over 300 million observed objects, including minor planets of the Solar System, brown dwarfs, low-mass stars, nebulae, star clusters and galaxies. In addition, 1 million objects were cataloged in the 2MASS Extended Source Catalog (2MASX). The cataloged objects are designated with a "2MASS" and "2MASX" prefix, respectively.
Gattini-IR is a survey telescope that observes in the near-infrared and started operation at the Palomar Observatory in late 2018.
It is planned to survey the entire accessible sky every night. It has a 2048x2048 sensor, and will observe in the J band (1.25um) infrared. Each nights images will be sensitive down to magnitude (MAB) 16.4, and by stacking a weeks images should be sensitive to MAB 17.5.