ISO deep far-infrared survey in the “Lockman Hole”

Abstract

Abstract. We present the catalogs and source counts for the C 90 (reference wavelength of 90 µm) and C 160 (170 µm) bands, which were extracted from our analysis of an ISO deep far-infrared survey conducted as part of the Japan/UH ISO cosmology project. The total survey area is ∼0.9 deg 2 in two fields within the Lockman Hole. The analysis consists of source extraction using the IRAF DAOPHOT package and simulations carried out by adding artificial sources to the maps to estimate the detection rate, the flux bias, the positional accuracy, and the noise. The flux calibration was performed using the Sb galaxy UGC 06009 -the photometric error was estimated to be ∼50% at C 90 and ∼65% at C 160. The total noise estimated from the simulation is dominated by the confusion noise due to the high source density. The confusion noise is ∼20 mJy at C 90 and ∼35 mJy at C 160, which is much larger than the instrumental noise which is at the level of a few mJy or less. The catalogs were constructed by selecting 223 C 90 sources and 72 C 160 sources with a Signal to Noise Ratio (S NR) of three or greater. The distribution of the observed associations between C 90 and C 160 sources indicates that the 1σ positional errors are ∼20 and ∼35 at C 90 and C 160, respectively. The corrections for the detection rate and the flux bias are significant for sources fainter than 200 mJy at C 90 and 250 mJy at C 160. Most of the sources detected both at C 90 and C 160 have a F(C 160)/F(C 90) color redder than the Sb galaxy UGC 06009. Such a red color could result from reddening due to the flux bias or a K-correction brightening due to the effect of redshift. Red sources brighter than 200 mJy at C 160 may be very luminous galaxies like Arp 220 at moderate redshift. The source counts are derived by applying the corrections for the detection rate and flux bias. The resultant counts are quite consistent with the constraints derived from the fluctuation analysis performed in Paper II. The C 160 counts are also consistent with the results from the FIRBACK project. Our C 90 survey, which is 2-3 times deeper than those previously published, reveals an upturn in the count slope at around 200 mJy. While recent models give a reasonable fit to the C 160 counts, none of them are successful in accounting for the upturn in the C 90 counts. If the upturn is caused by ultraluminous IR galaxies, their redshifts would need to be at z ∼ 0.5, implying a major event in galaxy evolution at moderate redshift.

Dusty star-forming galaxies at high redshift

“…Figure 12 illustrates both 850-870µm number counts (from Scuba, Laboca, Scuba-2, and ALMA Blain et al, 1999;Scott et al, 2002;Chapman et al, 2002;Cowie et al, 2002;Borys et al, 2003;Webb et al, 2003;Barnard et al, 2004;Coppin et al, 2006;Scott et al, 2006;Knudsen et al, 2008;Beelen et al, 2008;Weiß et al, 2009a;Karim et al, 2013;Casey et al, 2013;Chen et al, 2013a) and 450-500µm (from Scuba, Herschel and Scuba-2 Smail et al, 2002;Oliver et al, 2010;Clements et al, 2010;Béthermin et al, 2012b;Geach et al, 2013;Casey et al, 2013;Chen et al, 2013a). Figure 13 illustrates other infrared and submillimeter number counts in the literature in direct units, from 70µm Béthermin et al, 2010a;Berta et al, 2011), 100µm (Héraudeau et al, 2004;Rodighiero & Franceschini, 2004;Kawara et al, 2004;Berta et al, 2011;Magnelli et al, 2013b), 160µm Kawara et al, 2004;Béthermin et al, 2010a;Berta et al, 2011;Magnelli et al, 2013b), 250µm and 350µm Chen+13 (850) Casey+13 (850 Figure 12: Differential submillimeter number counts at 850µm/870µm (left) and 450-500 µm (right). The 850µm and 870µm number counts come the initial Scuba surveys …”

“…The 70µm data is collated from Spitzer MIPS Béthermin et al, 2010a) and Herschel PACS . At 100µm, data are from the ISOPHOT instrument aboard ISO (Héraudeau et al, 2004;Rodighiero & Franceschini, 2004;Kawara et al, 2004) and Herschel PACS Magnelli et al, 2013b). At 160µm-170µm, data are from Spitzer MIPS Béthermin et al, 2010a), ISO ISOPHOT (Kawara et al, 2004), and Herschel PACS Magnelli et al, 2013b).…”

“…At 100µm, data are from the ISOPHOT instrument aboard ISO (Héraudeau et al, 2004;Rodighiero & Franceschini, 2004;Kawara et al, 2004) and Herschel PACS Magnelli et al, 2013b). At 160µm-170µm, data are from Spitzer MIPS Béthermin et al, 2010a), ISO ISOPHOT (Kawara et al, 2004), and Herschel PACS Magnelli et al, 2013b). At both 250µm and 350µm, data come from BLAST Béthermin et al, 2010b) and Herschel SPIRE Clements et al, 2010;Béthermin et al, 2012b).…”

The Cosmic Evolution of Hard X-Ray-selected Active Galactic Nuclei

“…36b). The second open diamond in the figure shows the 3 upper limit at 170 m, which is based on the nondetections of the two X-ray sources in the Kawara et al (2004) catalog. For the broad-line AGNs (Fig.…”

“…For the broad-line AGNs (Fig. 36a), we show the 3 upper limits at both 90 and 170 m, which are based on the nondetections of the X-ray-bright broad-line AGNs in the Kawara et al (2004) catalog.…”