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Massive galaxy clusters undergo strong evolution from z ∼ 1.6 to z ∼ 0.5, with overdense environments at high- z characterized by abundant dust-obscured star formation and stellar mass growth which rapidly give way to widespread quenching. Data spanning the near- to far-infrared (IR) can directly trace this transformation; however, such studies have largely been limited to the massive galaxy end of cluster populations. In this work, we present 'total light' stacking techniques spanning |$3.4\!-\!500\, \mu$| m aimed at revealing the total cluster emission, including low-mass members and potential intracluster dust. We detail our procedures for  WISE, Spitzer , and  Herschel imaging, including corrections to recover the total stacked emission in the case of high fractions of detected galaxies. We apply our techniques to 232 well-studied log |$\, M_{200}/\mathrm{M}_{\odot }\sim 13.8$| clusters in multiple redshift bins, recovering extended cluster emission at all wavelengths. We measure the averaged IR radial profiles and spectral energy distributions (SEDs), quantifying the total stellar and dust content. The near-IR profiles are well described by an NFW model with a high (c ∼ 7) concentration. Dust emission is similarly concentrated, albeit suppressed at  |$r\lesssim 0.3\,$| Mpc. The measured SEDs lack warm dust, consistent with the colder SEDs of low-mass galaxies. We derive total stellar masses consistent with the theoretical M halo− M ⋆ relation and specific star formation rates that evolve strongly with redshift, echoing that of log |$\, M_{\star }/\mathrm{M}_{\odot }\gtrsim 10$| cluster galaxies. Separating out the massive population reveals the majority of cluster far-IR emission (⁠|$\sim 70\!-\!80{{\ \rm per\ cent}}$|⁠) is provided by the low-mass constituents, which differs from field galaxies. This effect may be a combination of mass-dependent quenching and excess dust in low-mass cluster galaxies. [ABSTRACT FROM AUTHOR]

We present a new submm/mm galaxy counterpart identification technique which builds on the use of Spitzer Infrared Array Camera (IRAC) colours as discriminators between likely counterparts and the general IRAC galaxy population. Using 102 radio- and Submillimeter Array-confirmed counterparts to AzTEC sources across three fields [Great Observatories Origins Deep Survey-North, -South and Cosmic Evolution Survey (COSMOS)], we develop a non-parametric IRAC colour–colour characteristic density distribution, which, when combined with positional uncertainty information via likelihood ratios, allows us to rank all potential IRAC counterparts around submillimetre galaxies (SMGs) and calculate the significance of each ranking via the reliability factor. We report all robust and tentative radio counterparts to SMGs, the first such list available for AzTEC/COSMOS, as well as the highest ranked IRAC counterparts for all AzTEC SMGs in these fields as determined by our technique. We demonstrate that the technique is free of radio bias and thus applicable regardless of radio detections. For observations made with a moderate beam size (∼18 arcsec), this technique identifies ∼85 per cent of SMG counterparts. For much larger beam sizes (≳30 arcsec), we report identification rates of 33–49 per cent. Using simulations, we demonstrate that this technique is an improvement over using positional information alone for observations with facilities such as AzTEC on the Large Millimeter Telescope and Submillimeter Common User Bolometer Array 2 on the James Clerk Maxwell Telescope. [ABSTRACT FROM AUTHOR]

We present a study of the cosmic infrared background, which is a measure of the dust-obscured activity in all galaxies in the Universe. We venture to isolate the galaxies responsible for the background at 1 mm; with spectroscopic and photometric redshifts we constrain the redshift distribution of these galaxies. We create a deep 1.16 mm map (mJy) by combining the AzTEC 1.1 mm and MAMBO 1.2 mm data sets in the Great Observatories Origins Deep Survey North (GOODS-N) region. This combined map contains 41 secure detections, 13 of which are new. By averaging the 1.16 mm flux densities of individually undetected galaxies with flux densities Jy, we resolve 31-45 per cent of the 1.16 mm background. Repeating our analysis on the SCUBA map, we resolve a higher percentage (40-64 per cent) of the background. A majority of the background resolved (attributed to individual galaxies) at both wavelengths comes from galaxies at . If the ratio of the resolved submillimetre to millimetre background is applied to a reasonable scenario for the origins of the unresolved submillimetre background, 60-88 per cent of the total 1.16 mm background comes from galaxies at . [ABSTRACT FROM AUTHOR]

We present an analysis of the X-ray properties of 35 sub-mm galaxies (SMGs) in the Chandra Deep Field-North region. Using a sample of robust galaxies, with sub-arcsecond positions from Spitzer and/or radio counterparts, we find 16 objects ( per cent) with significant X-ray detections in the 2 Ms Chandra data. Six of these SMGs ( per cent) have measured X-ray luminosities or upper limits consistent with those expected based on the far-infrared or radio-derived star formation rate, and hence with the X-rays coming solely from star-forming processes. Extrapolating observed X-ray/star formation rate relations to the luminosity of the SMGs, we find that the X-ray-derived star formation rates are typically in the range of . In another seven sources ( per cent of the SMGs) a dominant active galactic nuclei (AGN) contribution to the X-ray emission is required, while in three more it is unclear whether the stellar process or accretion is responsible for the X-rays. Stacking of the X-ray-undetected SMGs reveals a highly significant (7σ) detection. Under the assumption that the stacked X-ray is due to star formation, this gives an average X-ray-derived star formation rate of around . We deduce that the AGN fraction in SMGs based on X-ray observations is per cent, which is towards the lower limit of previous estimates. Spectral analysis shows that in general, the SMGs are not heavily obscured in the X-ray but most of the SMGs classified as AGN show absorption with column densities in excess of . Of the secure AGN, the bolometric luminosity appears to be dominated by the AGN in only three cases. In around 85 per cent of the SMGs, the X-ray spectrum effectively rules out an AGN contribution that dominates the bolometric emission, even if the AGN is Compton thick. The evidence therefore suggests that intense star formation accounts for both the far-infrared and X-ray emission in most SMGs. We argue that, rather than having an especially high AGN fraction or duty cycle, SMGs have a high X-ray detection rate at very faint fluxes partly because of their high star formation rates and, in rarer cases, because the sub-mm emission is from an AGN. [ABSTRACT FROM AUTHOR]

We present results from a multiwavelength study of 29 sources (false detection probabilities <5 per cent) from a survey of the Great Observatories Origins Deep Survey-North (GOODS-N) field at 1.1 mm using the Astronomical Thermal Emission Camera (AzTEC). Comparing with existing 850 μm Submillimetre Common-User Bolometer Array (SCUBA) studies in the field, we examine differences in the source populations selected at the two wavelengths. The AzTEC observations uniformly cover the entire survey field to a 1σ depth of ∼1 mJy. Searching deep 1.4 GHz Very Large Array (VLA) and Spitzer 3–24 μm catalogues, we identify robust counterparts for 21 1.1 mm sources, and tentative associations for the remaining objects. The redshift distribution of AzTEC sources is inferred from available spectroscopic and photometric redshifts. We find a median redshift of , somewhat higher than for selected sources in the same field, and our lowest redshift identification lies at a spectroscopic redshift . We measure the 850 μm to 1.1 mm colour of our sources and do not find evidence for ‘850 μm dropouts’, which can be explained by the low signal-to-noise ratio of the observations. We also combine these observed colours with spectroscopic redshifts to derive the range of dust temperatures T, and dust emissivity indices β for the sample, concluding that existing estimates and are consistent with these new data. [ABSTRACT FROM AUTHOR]

We present a 1200-μm image of the Great Observatories Origin Deep Survey North (GOODS-N) field, obtained with the Max Planck Millimetre Bolometer array (MAMBO) on the IRAM 30-m telescope. The survey covers a contiguous area of 287 arcmin2 to a near-uniform noise level of . After Bayesian flux deboosting, a total of 30 sources are recovered (≥3.5σ). An optimal combination of our 1200-μm data and an existing 850-μm image from the Submillimetre Common-User Bolometer Array (SCUBA) yielded 33 sources (≥4σ). We combine our GOODS-N sample with those obtained in the Lockman Hole and ELAIS N2 fields ( Scott et al. 2002 ; Greve et al. 2004 ) in order to explore the degree of overlap between 1200- and 850-μm-selected galaxies (hereafter SMGs), finding no significant difference between their distributions. However, a noise-weighted stacking analysis yields a significant detection of the 1200-μm-blank SCUBA sources, , whereas no significant 850-μm signal is found for the 850-μm-blank MAMBO sources . The hypothesis that the distribution of SCUBA sources is also representative of the MAMBO population is rejected at the ∼4σ level, via Monte Carlo simulations. Therefore, although the populations overlap, galaxies selected at 850 and 1200 μm are different, and there is compelling evidence for a significant 1200-μm-detected population which is not recovered at 850 μm. These are submillimetre dropouts (SDOs), with , requiring very cold dust or unusual spectral energy distributions , unless SDOs reside beyond the redshift range observed for radio-identified SMGs, i.e. at . [ABSTRACT FROM AUTHOR]

We explore the epoch dependence of number density and star formation rate for submillimetre galaxies (SMGs) found at 850 μm. The study uses a sample of 38 SMG in the Great Observatories Origins Deep Survey (GOODS)-N field, for which cross-waveband identifications have been obtained for 35/38 members together with redshift measurements or estimates. A maximum-likelihood analysis is employed, along with the ‘single-source-survey’ technique. We find a diminution in both space-density and star formation rate at z > 3, closely mimicking the redshift cut-offs found for quasi-stellar objects (QSOs) selected in different wavebands. The diminution in redshift is particularly marked at a significance level too small to measure. The data further suggest, at a significance level of about 0.001, that two separately evolving populations may be present, with distinct luminosity functions. These results parallel the different evolutionary behaviours of Luminous Infrared Galaxies and Ultra-Luminous Infrared Galaxies, and represent another manifestation of ‘cosmic down-sizing’, suggesting that differential evolution extends to the most extreme star-forming galaxies. [ABSTRACT FROM AUTHOR]

We present spectral energy distributions (SEDs), Spitzer colours, and infrared (IR) luminosities for 850-μm selected galaxies in the Great Observatories Origins Deep Survey Northern (GOODS-N) field. Using the deep Spitzer Legacy images and new data and reductions of the Very Large Array- Hubble Deep Field (VLA-HDF) radio data, we find statistically secure counterparts for 60 per cent (21/35) of our submillimetre (submm) sample, and identify tentative counterparts for another 12 objects. This is the largest sample of submm galaxies with statistically secure counterparts detected in the radio and with Spitzer. Half of the secure counterparts have spectroscopic redshifts, while the other half have photometric redshifts. We find that in most cases the 850-μm emission is dominated by a single 24-μm source, with a median flux density of 241 μJy, leading to a median 24-to-850-μm flux density ratio of 0.040. A composite rest-frame SED shows that the submm sources peak at longer wavelengths than those of local ultraluminous infrared galaxies (ULIRGs). Using a basic grey-body model, 850-μm selected galaxies appear to be cooler than local ULIRGs of the same luminosity. This demonstrates the strong selection effects, both locally and at high redshift, which may lead to an incomplete census of the ULIRG population. The SEDs of submm galaxies are also different from those of their high-redshift neighbours, the near-IR selected BzK galaxies, whose mid-IR-to-radio SEDs are more like those of local ULIRGs. Using 24-μm, 850-μm and 1.4-GHz observations, we fit templates that span the mid-IR through radio to derive the integrated IR luminosity (LIR) of the submm galaxies and find a median value of . By themselves, 24-μm and radio fluxes are able to predict reasonably well because they are relatively insensitive to temperature. However, the submm flux by itself consistently overpredicts when using spectral templates which obey the local ULIRG temperature–luminosity relation. The shorter Spitzer wavelengths sample the stellar bump at the redshifts of the submm sources, and we find that the Spitzer photometry alone provides a model-independent estimate of the redshift, . The median redshift for our secure submm counterparts is 2.0. Using X-ray and mid-IR data, only 5 per cent of our secure counterparts (1/21) show strong evidence for an active galactic nucleus dominating the LIR. [ABSTRACT FROM AUTHOR]

Bright submillimetre (sub-mm) galaxies are expected to arise in massive highly biased haloes, and hence exhibit strong clustering. We argue that a valuable tool for measuring these clustering properties is the cross-correlation of sub-mm galaxies with faint optically selected sources. We analyse populations of sub-mm detected and optical galaxies in the Great Observatories Origins Deep Survey-North (GOODS-N) survey area. Using optical/infrared photometric-redshift information, we search for correlations induced by two separate effects: (i) cosmic magnification of background sub-mm sources by foreground dark matter haloes traced by optical galaxies at lower redshifts and (ii) galaxy clustering due to sub-mm and optical sources tracing the same population of haloes where their redshift distributions overlap. Regarding cosmic magnification, we find no detectable correlation. Our null result is consistent with a theoretical model for the cosmic magnification, and we show that a dramatic increase in the number of sub-mm sources will be required to measure the effect reliably. Regarding clustering, we find evidence at the 3.5σ level for a cross-correlation between sub-mm and optical galaxies analysed in identical photometric redshift slices. The data hint that the sub-mm sources have an enhanced bias parameter compared to the optically selected population (with a significance of 2σ). The next generation of deep sub-mm surveys can potentially perform an accurate measurement of each of these cross-correlations, adding a new set of diagnostics for understanding the development of massive structure in the Universe. [ABSTRACT FROM AUTHOR]

We present a new submillimetre (submm) super-map in theHubble Deep FieldNorth (HDF-N) region (Great Observatories Origins Deep Survey North, GOODS-N, field), containing 40 statistically robust sources at 850 μm. This map contains additional data, and several new sources, including one of the brightest blank-sky extragalactic submm sources ever detected. We have used the Advanced Camera for Surveys (ACS)Hubble Space Telescope(HST) images and ground-based near-infrared (IR) observations from the Great Observatories Origins Deep Survey (GOODS), along with deep radio observations, to develop a systematic approach for counterpart identification. With the depth achieved by this survey, optical counterparts have been found for all the radio-detected (RD) submm sources. We have used the colours, morphologies and photometric redshifts of these secure identifications to help identify counterparts to the radio-undetected (RU) sources, finding that certain combinations of optical properties can be used to successfully identify the counterpart to a submm source. 72 per cent of our sources with optical coverage have a unique optical counterpart using our new techniques for counterpart identification and an additional 18 per cent have more than one possibility that meet our criteria in the ACS images. Thus, only∼10 per cent of our sources lack a plausible optical/near-IR counterpart, meaning that we have the first sample of Submillimetre Common User Bolometer Array (SCUBA) sources that is nearly completely identified in the optical. We have found a much higher extremely red object (ERO) rate than other submm surveys, as a result of the increased depth in the optical images. The median photometric redshift (and quartile range), from optical and near-IR data, is 1.7 (1.3–2.5) for the RD submm sources and rises to 2.3 (1.3–2.7) for the RU subsample. We find interesting correlations between the 850-μm flux and both thei775 magnitude and the photometric redshift, from which there appears to be an absence of high-redshift faint counterparts to the lower flux density SCUBA sources. While the quantitative morphologies span a range of values, in general the submm galaxies show larger sizes and a higher degree of asymmetry than other galaxy populations at the same redshifts. In the Appendix, we discuss several improvements in our data analysis procedure, including methods of testing for source reliability. [ABSTRACT FROM AUTHOR]

We present radio, optical and X-ray-detected counterparts to the submillimetre sources found using SCUBA in theHubble Deep FieldNorth region (GOODS-N). A new counterpart identification statistic is developed to identify properties of galaxies detected at other wavelengths that can be used to aid counterpart identification. We discriminate between criteria that can use used to pre-select submillimetre bright objects, and those that identify the counterpart to a known submillimetre object. Optically faint galaxies detected in the deepest 1.4-GHz radio continuum maps are the only effective way of pre-selecting SCUBA galaxies, and radio sources are the best way to identify counterparts to known submillimetre detections. Looking at radio spectral indices, only the steeper sources (indicative of star formation) are detected in the submillimetre range. Although we find several X-ray identifications, we show that deepChandraimages do not contribute to counterpart identifications, as in all cases they are already detected in the more easily obtained VLA radio maps. We also find no evidence for clustering betweenChandraand SCUBA sources in this field. For a known SCUBA position, the reddest source tends to be the correct association, although we can find no cut on colour, magnitude or clustering property that efficiently pre-selects for SCUBA sources. 15-μmISOsources are statistically detected by SCUBA, but the limiting mid-infrared flux is not low enough to provide useful constraints. We present postage stamp strips for each SCUBA detection in separate bands from X-ray to radio bands, providing direct visual evidence that approximately half of the submillimetre sources in this field remain unidentified, despite an abundance of deep multiwavelength data. [ABSTRACT FROM AUTHOR]