Open AccessSilicate‐break galaxies: an efficient selection method for distant ultraluminous infrared galaxies
Author(s) -
Takagi T.,
Pearson C. P.
Publication year - 2005
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 - 10.1111/j.1365-2966.2004.08624.x
Subject(s) - physics , astrophysics , galaxy , luminous infrared galaxy , astronomy , redshift , star formation , silicate , spitzer space telescope , infrared , galaxy formation and evolution , telescope
We present a photometric selection method for ultraluminous infrared galaxies (ULIRGs) in the redshift range of z = 1–2 . We utilize the most prominent spectral feature of ULIRGs, i.e. the silicate absorption feature at 9.7 μm and an optimized filter system at mid‐infrared wavelengths. These ‘ silicate‐break ’ galaxies could be selected by using colour anomalies arising from the silicate absorption feature around 9.7(1 + z ) μm . Such filter systems are available on the Spitzer Space Telescope but we suggest that the most promising selection criteria would be given with mid‐infrared bands of the ASTRO‐F satellite due to a more comprehensive set of filter bands than that of Spitzer . We study the selection method of silicate‐break galaxies with the SED model of both starbursts and quiescent star‐forming galaxies, and then verify the method by using the observed spectra of nearby galaxies. We would expect that about 1000 candidates of silicate‐break galaxies could be detected per square degree in current and future mid‐infrared surveys. The silicate‐break selection criteria will break the degeneracy between various galaxy evolution models for extragalactic source counts and place strong limits on the star formation activity at z = 1–2 . Applying our silicate‐break technique to initial Spitzer results we have tentatively identified the first candidate silicate‐break galaxy at z = 1.6 .