Open AccessThe differential magnification of high‐redshift ultraluminous infrared galaxies
Author(s) -
Blain A. W.
Publication year - 1999
Publication title -
monthly notices of the royal astronomical society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.058
H-Index - 383
eISSN - 1365-2966
pISSN - 0035-8711
DOI - 10.1046/j.1365-8711.1999.02426.x
Subject(s) - physics , astrophysics , luminous infrared galaxy , redshift , galaxy , james clerk maxwell telescope , luminosity , astronomy , photometric redshift , star formation
A class of extremely luminous high‐redshift galaxies has recently been detected in unbiased submillimetre‐wave surveys using the Submillimetre Common‐User Bolometer Array (SCUBA) camera at the James Clerk Maxwell Telescope. Most of the luminosity of these galaxies is emitted from warm interstellar dust grains, and they could be the high‐redshift counterparts of the low‐redshift ultraluminous infrared galaxies (ULIRGs). Only one ‐‐ SMM J02399‐0136 ‐‐ has yet been studied in detail. Three other very luminous high‐redshift dusty galaxies with well‐determined spectral energy distributions in the mid‐infrared waveband are known ‐‐ IRAS F10214+4724, H1413+117 and APM 08279+5255. These were detected serendipitously rather than in unbiased surveys, and are all gravitationally lensed by a foreground galaxy. Two ‐‐ H1413+117 and APM 08279+5255 ‐‐ appear to emit a significantly greater fraction of their luminosity in the mid‐infrared waveband, compared with both low‐redshift ULIRGs and high‐redshift submillimetre‐selected galaxies. This can be explained by a systematically greater lensing magnification of hotter regions of the source compared with cooler regions: differential magnification. This effect can confuse the interpretation of the properties of distant ultraluminous galaxies that are lensed by intervening galaxies, but offers a possible way to investigate the temperature distribution of dust in their nuclei on scales of tens of pc.