GROUND-BASED Paα NARROW-BAND IMAGING OF LOCAL LUMINOUS INFRARED GALAXIES. I. STAR FORMATION RATES AND SURFACE DENSITIES

• Published in: The Astrophysical journal. Supplement series Vol. 217; no. 1; pp. 1 - 26
• Main Authors: Tateuchi, Ken, Konishi, Masahiro, Motohara, Kentaro, Takahashi, Hidenori, Kato, Natsuko Mitani, Kitagawa, Yutaro, Todo, Soya, Toshikawa, Koji, Sako, Shigeyuki, Uchimoto, Yuka K
• Format: Journal Article
• Language: English
• Published: United States 01.03.2015
• Subjects: ASTROPHYSICS, COSMOLOGY AND ASTRONOMY; BOLOMETERS; CAMERAS; CORRECTIONS; CORRELATIONS; COSMIC DUST; DENSITY; Fluxes; GALAXIES; Imaging; Infrared; INFRARED SPECTRA; LUMINOSITY; Scatter; STAR EVOLUTION; Star formation; STARS; SURFACES; TELESCOPES
• ISSN: 1538-4365; 0067-0049; 1538-4365
• DOI: 10.1088/0067-0049/217/1/1

Luminous infrared galaxies (LIRGs) are enshrouded by a large amount of dust produced by their active star formation, and it is difficult to measure their activity in optical wavelengths. We have carried out Pa alpha narrow-band imaging observations of 38 nearby star forming galaxies including 33 LIRGs listed in the IRAS Revised Bright Galaxy Sample catalog with the Atacama Near InfraRed camera on the University of Tokyo Atacama Observatory (TAO) 1.0 m telescope (miniTAO). Star formation rates (SFRs) estimated from the Pa alpha fluxes, corrected for dust extinction using the Balmer decrement method (typically A sub(V)~ 4.3 mag), show a good correlation with those from the bolometric infrared luminosity of the IRAS data within a scatter of 0.27 dex. This suggests that the correction of dust extinction for the Pa alpha flux is sufficient in our sample. We measure the physical sizes and surface densities of infrared luminosities ([summationoperator] sub()LIR) and the SFR ([summationoperator] sub(SFR)) of star forming regions for individual galaxies, and we find that most of the galaxies follow a sequence of local ultra-luminous or luminous infrared galaxies (U/LIRGs) on the L(IR)-[summationoperator] sub()LIR)and SFR-[summationoperator] sub(SFR) plane. We confirm that a transition of the sequence from normal galaxies to U/LIRGs is seen at L(IR) = 8 x 10 super(10) L sub([middot in circle]). Also, we find that there is a large scatter in physical size, different from normal galaxies or ULIRGs. Considering the fact that most U/LIRGs are merging or interacting galaxies, this scatter may be caused by strong external factors or differences in their merging stages.