[en] We present far-infrared (FIR) properties of an extremely luminous infrared galaxy (ELIRG) at z _spec = 3.703, WISE J101326.25+611220.1 (WISE 1013+6112). This ELIRG is selected as an IR-bright dust-obscured galaxy based on the photometry from the Sloan Digital Sky Survey and the Wide-field Infrared Survey Explorer (WISE). In order to derive its accurate IR luminosity, we perform follow-up observations at 89 and 154 μm using the High-resolution Airborne Wideband Camera-plus (HAWC+) on board the 2.7 m Stratospheric Observatory For Infrared Astronomy (SOFIA) telescope. We conduct spectral energy distribution (SED) fitting with CIGALE using 15 photometric data (0.4–1300 μm). We successfully pin down FIR SED of WISE 1013+6112 and its IR luminosity is estimated to be L _IR = (1.62 ± 0.08) × 10¹⁴ L _☉, making it one of the most luminous IR galaxies in the universe. We determine the dust temperature of WISE 1013+6112 is T _dust = 89 ± 3 K, which is significantly higher than that of other populations such as submillimeter galaxies and FIR-selected galaxies at similar IR luminosities. The resultant dust mass is M _dust = (2.2 ± 0.1) × 10⁸ M _☉. This indicates that WISE 1013+6112 has a significant active galactic nucleus and star-forming activity behind a large amount of dust.

[en] We examine the robustness of the color–color selection of quiescent galaxies (QGs) against contamination of dusty star-forming galaxies using the latest submillimeter data. We selected 18,304 QG candidates out to z ∼ 3 using the commonly adopted NUV–r–J selection based on the high-quality multiwavelength COSMOS2015 catalog. Using extremely deep 450 and 850 μm catalogs from the latest JCMT SCUBA-2 Large Programs, S2COSMOS and STUDIES, as well as the Atacama Large Millimeter/submillimeter Array submillimeter, VLA 3 GHz, and Spitzer MIPS 24 μm catalogs, we identified luminous, dusty, star-forming galaxies among the QG candidates. We also conducted stacking analyses in the SCUBA-2 450 and 850 μm images to look for less-luminous dusty galaxies among the QG candidates. By cross matching to the 24 μm and 3 GHz data, we were able to identify a subgroup of “IR-radio-bright” QGs that possess strong 450 and 850 μm stacking signals. The potential contamination of these luminous and less-luminous dusty galaxies accounts for approximately 10% of the color-selected QG candidates. In addition, there exists a spatial correlation between the luminous star-forming galaxies and the QGs at a ≲60 kpc scale. Finally, we found a high QG fraction among radio active galactic nuclei (AGNs) at z < 1.5. Our data show a strong correlation between QGs and radio AGNs, which may suggest a connection between the quenching process and the radio-mode AGN feedback.

[en] We construct a SCUBA-2 450 μm map in the COSMOS field that covers an area of 300 arcmin² and reaches a 1σ noise level of 0.65 mJy in the deepest region. We extract 256 sources detected at 450 μm with signal-to-noise ratios >4.0 and analyze the physical properties of their multiwavelength counterparts. We find that most of the sources are at z ≲ 3, with a median of $z={1.79}_{-<!--\; ???\; -->0.15}^{+0.03}\mathrm{\%<!--\; \%\; -->}$. About ${35}_{-<!--\; ???\; -->25}^{+32}\mathrm{\%<!--\; \%\; -->}$ of our sources are classified as starburst galaxies based on their total star formation rates (SFRs) and stellar masses (M _*). By fitting the far-infrared spectral energy distributions, we find that our 450 μm selected sample has a wide range of dust temperatures (20 K ≲ T _d ≲ 60 K), with a median of $T_{\mathrm{d}}={38.3}_{-<!--\; ???\; -->0.9}^{+0.4}$ K. We do not find a redshift evolution in dust temperature for sources with $L_{\mathrm{I}\mathrm{R}}><!--\; >\; -->{10}^{12}{L}_{\odot <!--\; ???\; -->}$ at z < 3. However, we find a moderate correlation where the dust temperature increases with the deviation from the SFR–M _* relation. The increase in dust temperature also correlates with optical morphology, which is consistent with merger-triggered starbursts in submillimeter galaxies. Our galaxies do not show the tight IRX–β _UV correlation that has been observed in the local universe. We construct the infrared luminosity functions of our 450 μm sources and measure their comoving SFR densities (SFRDs). The contribution of the $L_{\mathrm{I}\mathrm{R}}><!--\; >\; -->{10}^{12}{L}_{\odot <!--\; ???\; -->}$ population to the SFRD rises dramatically from z = 0 to 2 (∝(1 + z)^3.9±1.1) and dominates the total SFRD at z ≳ 2.

[en] We analyze an extremely deep 450 μm image (1σ = 0.56 mJy beam⁻¹) of a ≃300 arcmin² area in the CANDELS/COSMOS field as part of the Sub-millimeter Common User Bolometric Array-2 Ultra Deep Imaging EAO Survey. We select a robust (signal-to-noise ratio ≥4) and flux-limited (≥4 mJy) sample of 164 submillimeter galaxies (SMGs) at 450 μm that have K-band counterparts in the COSMOS2015 catalog identified from radio or mid-infrared imaging. Utilizing this SMG sample and the 4705 K-band-selected non-SMGs that reside within the noise level ≤1 mJy beam⁻¹ region of the 450 μm image as a training set, we develop a machine-learning classifier using K-band magnitude and color–color pairs based on the 13-band photometry available in this field. We apply the trained machine-learning classifier to the wider COSMOS field (1.6 deg²) using the same COSMOS2015 catalog and identify a sample of 6182 SMG candidates with similar colors. The number density, radio and/or mid-infrared detection rates, redshift and stellar-mass distributions, and the stacked 450 μm fluxes of these SMG candidates, from the S2COSMOS observations of the wide field, agree with the measurements made in the much smaller CANDELS field, supporting the effectiveness of the classifier. Using this SMG candidate sample, we measure the two-point autocorrelation functions from z = 3 down to z = 0.5. We find that the SMG candidates reside in halos with masses of ≃(2.0 ± 0.5) × 10¹³ h ⁻¹ M _☉ across this redshift range. We do not find evidence of downsizing that has been suggested by other recent observational studies.