Sunday, July 16, 2017

New Ultra-Bright Submillimeter Galaxy Discovered

The multiple images of the discovered galaxy are indicated by white arrows (bottom right shows the scale of the image in seconds of arc). Credit: Hubble Space Telescope (HST)

Spanish astronomers have identified new ultra-bright submillimeter galaxy thanks to the gravitational lensing effect. The newly found galaxy, designated WISE J132934.18+224327.3 (or Cosmic Eyebrow), could offer important hints on the formation and evolution processes of massive galaxies. The findings were detailed in a paper published July 8 on the arXiv pre-print server.

Gravitational lensing takes place when a large mass bends the path of background light. This effect allows astronomers to see and study distant galaxies from the early Universe, which otherwise would be impossible to see. Massive galaxy cluster often serve as gravitational lenses enhancing the apparent brightness of submillimeter galaxies.

Submillimeter galaxies (SMGs) are a class of ultraluminous infrared galaxies at redshift between 2.0 and 4.0. They are massive, extremely dusty and are believed to be progenitors of present-day elliptical galaxies. SMGs are important for astronomers as they could provide invaluable clues on the formation and evolution of massive galaxies in the distant universe.

Recently, a team of astronomers led by Anastasio Díaz-Sánchez of the Polytechnic University of Cartagena, Spain, has conducted a search for bright lensed SMGs in AllWISE and Planck compact source catalogs provided by two space missions. They carried out a cross-matching between these full-sky catalogs with the aim of finding analogs of the submillimeter galaxy SMMJ2135, known as the Cosmic Eyelash. Their studies resulted in the detection of WISE J132934.18+224327.3 as a magnified submillimeter galaxy at redshift of 2.044.

“We report the discovery of WISE J132934.18+224327.3 as a magnified SMG at z = 2.044 with spectral energy distribution (SED) remarkably similar to that of the Cosmic Eyelash but higher apparent brightness at all wavelengths from visible to radio,” the team wrote in the paper.

The newly discovered galaxy is gravitationally magnified by a massive cluster at redshift of 0.44. According to the study, the intrinsic rest-frame 8-1000-µm luminosity of the lensed galaxy is 13 trillion times greater than that of our Sun.

“We calculate the rest-frame 8-1000-µm luminosity from direct integration of the data fit,” the paper reads.

The researchers noted that such luminosity indicates a likely star-formation rate between 500 to 2,000 solar masses per year.

The astronomers underlined that Cosmic Eyebrow is one of the brightest examples of SMGs known to date and could be very helpful in future more detailed high spatial resolution studies of star-forming regions in such dusty galaxies.

What is also noteworthy, the study conducted by Díaz-Sánchez’s team describes the first result of a search for the brightest examples in the sky of dusty star-forming high redshift galaxies using data from ESA’s Planck and NASA’s WISE (Wide-field Infrared Survey Explorer) space missions.

1 comment:

  1. IT IS CLEARLY OBSERVABLE A SPIRAL OF THE GALAXIES ...WHY WOULD THAT BE?cAN SOMONE CONSIDER A IMAGINARY PATH FOR LIGHT? WITH CORRESPONDING SPEEDS VARYING FROM THAT OF REAL NUMBERS?

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