Far Infrared Luminosity Function of Local Star-forming Galaxies in the AKARI Deep Field South
Chris Sedgwick, Stephen Serjeant, Chris Pearson, Shuji Matsuura, Mai Shirahata, Shinki Oyabu, Tomotsugu Goto, Hideo Matsuhara, D. L. Clements, Mattia Negrello, Glenn J. White
We present a far-infrared galaxy luminosity function for the local universe. We have obtained 389 spectroscopic redshifts for galaxies observed at 90 microns in the AKARI Deep Field South, using the AAOmega fibre spectrograph via optical identifications in the digitized sky survey and 4m-class optical imaging. For the luminosity function presented in this paper, we have used those galaxies which have redshifts 0<z<0.25, have optical magnitudes and are not part of a newly discovered cluster of galaxies (giving a total of 130 sources). Infrared and optical completeness functions were estimated using earlier Spitzer data and APM B-band optical data respectively, and the luminosity function has been prepared using the 1/Vmax method. We also separate the luminosity function between galaxies which show evidence of predominantly star-forming activity and predominantly active galactic nucleus (AGN) activity in their optical spectra. Our luminosity function is in good agreement with the previous 90 micron luminosity function from the European Large Area ISO Survey, and we also present a luminosity function with combined AKARI and ISO data. The result is in reasonable agreement with predictions based on the earlier IRAS 60 micron PSC-z catalogue, and with a recent backward evolution model.
The importance of multiwavelength astronomical surveys is discussed in the context of galaxy evolution. The AKARI Deep Field South (ADF-S) is a new, well placed survey field that is already the subject of studies at a wide range of wavelengths. A number of ADF-S observational programmes are discussed and the prospects for the ADF-S as a future resource for extragalactic astronomy is explored.
We present the first far-infrared luminosity function in the AKARI Deep Field South, a premier deep field of the AKARI Space Telescope, using spectroscopic redshifts obtained with AAOmega. To date, we have found spectroscopic redshifts for 389 galaxies in this field and have measured the local (z < 0.25) 90 micron luminosity function using about one-third of these redshifts. The results are in reasonable agreement with recent theoretical predictions.
In order to find counterparts of the detected objects in the AKARI Deep Field South (ADFS) in all available wavelengths, we searched public databases (NED, SIMBAD and others). Checking 500 sources brighter than 0.0482 Jy in the AKARI Wide-S band, we found 114 sources with possible counterparts, among which 78 were known galaxies. We present these sources as well as our first attempt to construct spectral energy distributions (SEDs) for the most secure and most interesting sources among them, taking into account all the known data together with the AKARI measurements in four bands.
To investigate the nature and properties of far-infrared (FIR) sources from the AKARI Deep Field South (ADF-S), we performed an extensive search for the counterparts of 1000 ADF-S objects brighter than 0.0301 Jy in the WIDE-S (90 $μ$m) AKARI band in the public databases (NED and SIMBAD). We analyzed the properties of the resulting sample: statistic of the identified objects, number counts, redshift distribution and morphological types. We also made a crude analysis of the clustering properties of the sources and constructed spectral energy distributions (SEDs) of 47 selected objects with the b…
The AKARI Deep Field South (ADF-S) is a large extragalactic survey field that is covered by multiple instruments, from optical to far-IR and radio. I summarise recent results in this and related fields prompted by the release of the Herschel far-IR/submm images, including studies of cold dust in nearby galaxies, the identification of strongly lensed distant galaxies, and the use of colour selection to find candidate very high redshift sources. I conclude that the potential for significant new results from the ADF-S is very great. The addition of new wavelength bands in the future, eg. from Euc…
The AKARI Deep Field South (ADF-S) is a ~12 sq. deg. region near the South Ecliptic Pole that has been observed with deep scans in the far-infrared by the AKARI satellite. As such it is becoming one of the key extragalactic survey fields. We here present complementary observations of the ADF-S conducted by the Spitzer Space Telescope at wavelengths of 24 and 70 micron. We extract source catalogs at each of these wavelengths reaching depths of ~ 0.2mJy at 24 micron and ~ 20mJy at 70 micron. We also apply an K-to-24 micron colour criterion to select objects with galaxy-like colours in the 24 mic…
The results of a deep 20 cm radio survey at 20 cm are reported of the AKARI Deep Field South (ADF-S) near the South Ecliptic Pole (SEP), using the Australia Telescope Compact Array telescope, ATCA. The survey has 1 sigma detection limits ranging from 18.7--50 microJy per beam over an area of ~1.1 sq degrees, and ~2.5 sq degrees to lower sensitivity. The observations, data reduction and source count analysis are presented, along with a description of the overall scientific objectives, and a catalogue containing 530 radio sources detected with a resolution of 6.2" x 4.9". The derived differentia…
We present the first detailed analysis of three extragalactic fields (IRAC Dark Field, ELAIS-N1, ADF-S) observed by the infrared satellite, AKARI, using an optimised data analysis toolkit specifically for the processing of extragalactic point sources. The InfraRed Camera (IRC) on AKARI complements the Spitzer space telescope via its comprehensive coverage between 8-24 microns filling the gap between the Spitzer IRAC and MIPS instruments. Source counts in the AKARI bands at 3.2, 4.1, 7, 11, 15 and 18 microns are presented. At near-infrared wavelengths, our source counts are consistent with coun…
We present early results from our multi-wavelength follow-up campaigns of the AKARI Deep Fields at the North and South Ecliptic Poles. We summarize our campaigns in this poster paper, and present three early outcomes. (a) Our AAOmega optical spectroscopy of the Deep Field South at the AAT has observed over 550 different targets, and our preliminary local luminosity function at 90 microns from the first four hours of data is in good agreement with the predictions from Serjeant & Harrison 2005. (b) Our GMRT 610 MHz imaging in the Deep Field North has reached ~30 microJy RMS, making this among th…
We present results of a 1.1 mm deep survey of the AKARI Deep Field South (ADF-S) with AzTEC mounted on the Atacama Submillimetre Telescope Experiment (ASTE). We obtained a map of 0.25 sq. deg area with an rms noise level of 0.32-0.71 mJy. This is one of the deepest and widest maps thus far at millimetre and submillimetre wavelengths. We uncovered 198 sources with a significance of 3.5-15.6 sigma, providing the largest catalog of 1.1 mm sources in a contiguous region. Most of the sources are not detected in the far-infrared bands of the AKARI satellite, suggesting that they are mostly at z ~ 1.…
The main aim of this work is the characterization of physical properties of galaxies detected in the far infrared (FIR) in the AKARI Deep Field-South (ADF-S) survey. Starting from a catalog of the 1 000 brightest ADF-S sources in the WIDE-S (90$μ$m) AKARI band, we constructed a subsample of galaxies with spectral coverage from the ultraviolet to the far infrared. We then analyzed the multiwavelength properties of this 90$μ$m selected sample of galaxies. For galaxies without known spectroscopic redshifts we computed photometric redshifts using the codes Photometric Analysis for Redshift Estimat…
We present the first measurement of the angular two-point correlation function for AKARI 90-$μ$m point sources, detected outside of the Milky Way plane and other regions characterized by high Galactic extinction, and categorized as extragalactic sources according to our far-infrared-color based criterion (Pollo et al. 2010). This is the first measurement of the large-scale angular clustering of galaxies selected in the far-infrared after IRAS measurements. Although a full description of clustering properties of these galaxies will be obtained by more detailed studies, using either spatial corr…
We report the detection and measurement of the absolute brightness and spatial fluctuations of the cosmic infrared background (CIB) with the AKARI satellite. We have carried out observations at 65, 90, 140 and 160 um as a cosmological survey in AKARI Deep Field South (ADF-S), which is one of the lowest cirrus regions with contiguous area on the sky. After removing bright galaxies and subtracting zodiacal and Galactic foregrounds from the measured sky brightness, we have successfully measured the CIB brightness and its fluctuations across a wide range of angular scales from arcminutes to degree…
The Stephan's Quintet (SQ, HCG92) was observed with the Far-Infrared Surveyor (FIS) aboard AKARI in four far-infrared (IR) bands at 65, 90, 140, and 160 um. The AKARI four-band images of the SQ show far-IR emission in the intergalactic medium (IGM) of the SQ. In particular, the 160 um band image shows single peak emission in addition to the structure extending in the North-South direction along the shock ridge as seen in the 140 um band, H2 emission and X-ray emission. Whereas most of the far-IR emission in the shocked region comes from the cold dust component, shock-powered [CII]158um emissio…
We present a preliminary analysis of clustering of galaxies luminous in the near- and mid-infrared as seen by seven various ilters of the AKARI IRC instrument from 2 $μ$m to 24 $μ$m in the the AKARI NEP-Deep field. We compare populations of galaxies detected in different filters and their clustering properties. We conclude that different AKARI filters allow to trace different populations composed mainly of star-forming galaxies located in different environments. In particular, the mid-infrared filters at redshift z $\sim$ 0.8 and higher trace a population of strongly evolving galaxies located …
We present mid-infrared (MIR) luminosity functions (LFs) of local star-forming (SF) galaxies in the AKARI NEP-Wide Survey field. In order to derive more accurate luminosity function, we used spectroscopic sample only. Based on the NEP-Wide point source catalogue containing a large number of infrared (IR) sources distributed over the wide (5.4 sq. deg.) field, we incorporated the spectroscopic redshift data for about 1790 selected targets obtained by optical follow-up surveys with MMT/Hectospec and WIYN/Hydra. The AKARI continuous 2 to 24 micron wavelength coverage as well as photometric data f…
We present the 9 and 18 micron luminosity functions (LFs) of galaxies at 0.006 < z < 0.8 (with an average redshift of ~ 0.04) using the AKARI mid-infrared all-sky survey catalog. We selected 243 galaxies at 9 micron and 255 galaxies at 18 micron from the Sloan Digital Sky Survey (SDSS) spectroscopy region. These galaxies were then classified by their optical emission lines, such as the line width of H_alpha or by their emission line ratios of [OIII]/H_beta and [NII]/H_alpha into five types: Type 1 active galactic nuclei (AGN) (Type 1); Type 2 AGN (Type 2); low-ionization narrow emission line g…
Submillimetre and millimetre-wave surveys with Herschel and the South Pole Telescope have revolutionised the discovery of strong gravitational lenses. Their follow-ups have been greatly facilitated by the multi-wavelength supplementary data in the survey fields. The forthcoming Euclid optical/near-infrared space telescope will also detect strong gravitational lenses in large numbers, and orbital constraints are likely to require placing its deep survey at the North Ecliptic Pole (the natural deep field for a wide class of ground-based and space-based observatories including AKARI, JWST and SPI…
We present the mid-infrared (MIR) properties of galaxies within a supercluster in the North Ecliptic Pole region at z?0.087 observed with the AKARI satellite. We use data from the AKARI NEP-Wide (5.4 deg2) IR survey and the CLusters of galaxies EVoLution studies (CLEVL) mission program. We show that near-IR (3 μm)-mid- IR (11 μm) color can be used as an indicator of the specific star formation rate and the presence of intermediate age stellar populations. From the MIR observations, we find that red-sequence galaxies consist not only of passively evolving red early-type galaxies, but also of 1)…
The importance of the far-infrared (FIR) mapping is demonstrated for a face-on spiral galaxy, M81, by analyzing its imaging data at 65, 90, and 140 μm taken by AKARI. Basic products are the dust temperature map, the dust optical depth map, and the colour-colour diagram. The main features are as follows. (i) The dust temperature derived from the total fluxes at 90 μm and 140 μm reflects the relatively low temperatures seen in the interarm and spiral arms excluding the warm spots, rather than the high temperatures in warm spots and the centre. This indicates that the total FIR luminosity is domi…
The AKARI FU-HYU mission program carried out mid-infrared imaging of several well studied Spitzer fields preferentially selecting fields already rich in multi-wavelength data from radio to X-ray wavelengths filling in the wavelength desert between the Spitzer IRAC and MIPS bands.We present the initial results for the FU-HYU survey in the GOODS-N field.We utilize the supreme multiwavelength coverage in the GOODS-N field to produce a multiwavelength catalogue from infrared to ultraviolet wavelengths, containing more than 4393 sources, including photometric redshifts. Using the FU-HYU catalogue w…
We have studied the star-formation and AGN activity of massive galaxies in the redshift range $z=0.4-2$, which are detected in a deep survey field using the AKARI InfraRed (IR) astronomical satellite and {\em Subaru} telescope toward the North Ecliptic Pole (NEP). The AKARI/IRC Mid-InfraRed (MIR) multiband photometry is used to trace their star-forming activities with the Polycyclic-Aromatic Hydrocarbon (PAH) emissions, which is also used to distinguish star-forming populations from AGN dominated ones and to estimate the Star Formation Rate (SFR) derived from their total emitting IR (TIR) lumi…
The Westerbork Radio Synthesis Telescope, WSRT, has been used to make a deep radio survey of an ~ 1.7 sq degree field coinciding with the AKARI North Ecliptic Pole Deep Field. The observations, data reduction and source count analysis are presented, along with a description of the overall scientific objectives. The survey consisted of 10 pointings, mosaiced with enough overlap to maintain a similar sensitivity across the central region that reached as low as 21 microJy per beam at 1.4 GHz. A catalogue containing 462 sources detected with a resolution of 17"x15" is presented. The differential s…
By cross-correlating AKARI infrared (IR) sources with the SDSS galaxies, we identified 2357 infrared galaxies with a spectroscopic redshift. This is not just one of the largest samples of local IR galaxies, but AKARI provides crucial FIR bands (9, 18, 65, 90, 140, and 160um) in accurately measuring galaxy SED across the peak of the dust emission at ~100um. By fitting modern IR SED models to the AKARI photometry, we measured the total infrared luminosity (L_IR) of individual galaxies more accurately. Using this L_IR, we constructed luminosity functions of infrared galaxies at a median redshift …
We present the results of the analysis of multiwavelength Spectral Energy Distributions (SEDs) of far-infrared galaxies detected in the AKARI Deep Field-South (ADF--S) Survey. The analysis uses a carefully selected sample of 186 sources detected at the 90 $μ$m AKARI band, identified as galaxies with cross-identification in public catalogues. For sources without known spectroscopic redshifts, we estimate photometric redshifts after a test of two independent methods: one based on using mainly the optical -- mid infrared range, and one based on the whole range of ultraviolet -- far infrared data.…
We present the physical properties of AKARI sources without optical counterparts in optical images from the Hyper Suprime-Cam (HSC) on the Subaru telescope. Using the AKARI infrared (IR) source catalog and HSC optical catalog, we select 583 objects that do not have HSC counterparts in the AKARI North Ecliptic Pole (NEP) wide survey field ($\sim 5$ deg$^{2}$). Because the HSC limiting magnitude is deep ($g_{\rm AB}$ $\sim 28.6$), these are good candidates for extremely red star-forming galaxies (SFGs) and/or active galactic nuclei (AGNs), possibly at high redshifts. We compile multi-wavelength …
The nearby universe remains the best laboratory to understand physical properties of galaxies and is a reference for any comparison with high redshift observations. The all sky (or very large) surveys performed from the ultraviolet (UV) to the far-infrared (far-IR) gives us large datasets with a very large wavelength coverage to perform a reference study. We want to investigate dust attenuation characteristics as well as star formation rate (SFR) calibrations on a sample of nearby galaxies observed over 13 bands from 0.15 to 160 microns. A sample of 363 galaxies is built from the AKARI /FIS al…
In this research, we provide a new, efficient method to select infrared (IR) active galatic nucleus (AGN). In the past, AGN selection in IR had been established by many studies using color-color diagrams. However, those methods have a problem in common that the number of bands is limited. The AKARI North Ecliptic Pole (NEP) survey was carried out by the AKARI Infrared Camera (IRC), which has 9 filters in mid-IR with a continuous wavelength coverage from 2 to 24$μ$m$^{-1}$. Based on the intrinsic different mid-IR features of AGN and star-forming galaxies (SFGs), we performed SED fitting to sepa…
We present the result of a systematic infrared 2.5-5 um spectroscopic study of 22 nearby infrared galaxies over a wide infrared luminosity range (10 < log(L_IR / Lsun) < 13) obtained from AKARI Infrared Camera (IRC). The unique band of the AKARI IRC spectroscopy enables us to access both the 3.3 um polycyclic aromatic hydrocarbon (PAH) emission feature from star forming activity and the continuum of torus-dust emission heated by an active galactic nucleus (AGN). Applying our AGN diagnostics to the AKARI spectra, we discover 14 buried AGNs. The large fraction of buried AGNs suggests that AGN ac…
Using mid-infrared (MIR) images of four photometric bands of the Infrared Camera (IRC) onboard the AKARI satellite, S7 (7 um), S11 (11 um), L15 (15 um), and L24 (24 um), we investigate the interstellar dust properties of the nearby pair of galaxies M51 with respect to its spiral arm structure. The arm and interarm regions being defined based on a spatially filtered stellar component model image, we measure the arm-to-interarm contrast for each band. The contrast is lowest in the S11 image, which is interpreted as that among the four AKARI MIR bands the S11 image best correlates with the spatia…
We have developed an efficient Active Galactic Nucleus (AGN) selection method using 18-band Spectral Energy Distribution (SED) fitting in mid-infrared (mid-IR). AGNs are often obscured by gas and dust, and those obscured AGNs tend to be missed in optical, UV and soft X-ray observations. Mid-IR light can help us to recover them in an obscuration free way using their thermal emission. On the other hand, Star-Forming Galaxies (SFG) also have strong PAH emission features in mid-IR. Hence, establishing an accurate method to separate populations of AGN and SFG is important. However, in previous mid-…
We have imaged an 11.5 sq. deg. region of sky towards the South Ecliptic Pole (RA = 04h43m, Dec = -53d40m, J2000) at 24 and 70 microns with MIPS, the Multiband Imaging Photometer for Spitzer. This region is coincident with a field mapped at longer wavelengths by AKARI and the Balloon-borne Large Aperture Submillimeter Telescope. We discuss our data reduction and source extraction procedures. The median depths of the maps are 47 microJy/beam at 24 micron and 4.3 mJy/beam at 70 micron. At 24 micron, we identify 93098 point sources with signal-to-noise ratio (SNR) >5, and an additional 63 resolve…
Infrared (IR) luminosity is fundamental to understanding the cosmic star formation history and AGN evolution. The AKARI IR space telescope performed all sky survey in 6 IR bands (9, 18, 65, 90, 140, and 160um) with 3-10 times better sensitivity than IRAS, covering the crucial far-IR wavelengths across the peak of the dust emission. Combined with a better spatial resolution, AKARI can much more precisely measure the total infrared luminosity (L_TIR) of individual galaxies, and thus, the total infrared luminosity density in the local Universe. By fitting IR SED models, we have re-measured L_TIR …
We study the behaviour of polycyclic aromatic hydrocarbon emission in galaxies at z=0.3-1.4 using 1868 samples from the revised catalogue of AKARI North Ecliptic Pole Deep survey. The continuous filter coverage at 2-24um makes it possible to measure 8um luminosity, which is dominated by polycyclic aromatic hydrocarbon emission for galaxies at up to z=2. We compare the IR8 (= LIR/L(8)) and 8um to 4.5um luminosity ratio (L(8)/L(4.5)) with the starburstiness, Rsb, defined as excess of specific star -formation rate over that of main-sequence galaxy. All AGN candidates were excluded from our sample…
We present a method of selection of 24~$μ$m galaxies from the AKARI North Ecliptic Pole (NEP) Deep Field down to $150 \mbox{ }μ$Jy and measurements of their two-point correlation function. We aim to associate various 24 $μ$m selected galaxy populations with present day galaxies and to investigate the impact of their environment on the direction of their subsequent evolution. We discuss using of Support Vector Machines (SVM) algorithm applied to infrared photometric data to perform star-galaxy separation, in which we achieve an accuracy higher than 80\%. The photometric redshift information, ob…
We present the survey strategy and the data characteristics of the North Ecliptic Pole (NEP) Wide Survey of AKARI. The survey was carried out for about one year starting from May 2006 with 9 passbands from 2.5 to 24 micron and the areal coverage of about 5.8 sq. degrees centered on NEP. The survey depth reaches to 21.8 AB magnitude near infrared (NIR) bands, and ~ 18.6 AB maggnitude at the mid infrared (MIR) bands such as 15 and 18 micron. The total number of sources detected in this survey is about 104,000, with more sources in NIR than in the MIR. We have cross matched infrared sources with …
We present a catalog of 191 extragalactic sources detected by the Atacama Cosmology Telescope (ACT) at 148 GHz and/or 218 GHz in the 2008 Southern survey. Flux densities span 14-1700 mJy, and we use source spectral indices derived using ACT-only data to divide our sources into two sub-populations: 167 radio galaxies powered by central active galactic nuclei (AGN), and 24 dusty star-forming galaxies (DSFGs). We cross-identify 97% of our sources (166 of the AGN and 19 of the DSFGs) with those in currently available catalogs. When combined with flux densities from the Australian Telescope 20 GHz …
We present the mid-infrared (MIR) observation of a nearby galaxy cluster, Abell 2255 by the AKARI space telescope. Using the AKARI's continuous wavelength coverage between 3-24 micron and the wide field of view, we investigate the properties of cluster member galaxies to see how the infall of the galaxies, the cluster substructures, and the cluster-cluster merger influence their evolution. We show that the excess of MIR (11 micron) flux is a good indicator to discriminate galaxies at different evolutionary stages, and divide galaxies into three classes accordingly : strong MIR-excess (N3-S11>0…
In order to understand the interaction between the central black hole and the whole galaxy or their co-evolution history along with cosmic time, a complete census of active galactic nuclei (AGN) is crucial. However, AGNs are often missed in optical, UV and soft X-ray observations since they could be obscured by gas and dust. A mid-infrared (mid-IR) survey supported by multiwavelength data is one of the best ways to find obscured AGN activities because it suffers less from extinction. Previous large IR photometric surveys, e.g., $WISE$ and $Spitzer$, have gaps between the mid-IR filters. Theref…
Polycyclic Aromatic Hydrocarbon (PAH) emission features dominate the mid-infrared spectra of star-forming galaxies and can be useful to calibrate star formation rates and diagnose ionized states of grains. However, the PAH 3.3 micron feature has not been studied as much as other PAH features since it is weaker than others and resides outside of Spitzer capability. In order to detect and calibrate the 3.3 micron PAH emission and investigate its potential as a star formation rate indicator, we carried out an AKARI mission program, AKARI mJy Unbiased Survey of Extragalactic Survey (AMUSES) and co…
(Abridge) We study statistical intrinsic shape of star-forming BzK galaxies (sBzK galaxies) at z~2 in both rest-frame UV and rest-frame optical wavelengths. The sBzK galaxies are selected down to K(AB)=24.0 mag in the GOODS-South and SXDS fields, where high-resolution images from Hubble Space Telescope are publicly available. 57% (583) of all 1028 galaxies in GOODS-S show a single component in the ACS/F850LP image. As WFC3/F160W images cover only some part of GOODS-S and SXDS, 724/1028 and 2500/29835 sBzK galaxies in the GOODS-S and SXDS have the WFC3 coverage. 86% (626) and 82% (2044) of the …
For star-forming galaxies, we investigate a global relation between polycyclic aromatic hydrocarbon (PAH) emission luminosity at 3.3 um, L_PAH3.3, and infrared (8-1000 um) luminosity, L_IR, to understand how the PAH 3.3 um feature relates to the star formation activity. With AKARI, we performed near-infrared (2.5-5 um) spectroscopy of 184 galaxies which have L_IR \sim 10^8 - 10^13 L_sun. We classify the samples into infrared galaxies (IRGs; L_IR < 10^11 L_sun), luminous infrared galaxies (LIRGs; L_IR \sim 10^11 -10^12 L_sun) and ultra luminous infrared galaxies (ULIRGs; L_IR > 10^12 L_sun). We…
The results of the recently published spectroscopically complete survey of dusty star-forming galaxies detected by the South Pole Telescope (SPT) over 2500 deg^2 proved to be challenging for galaxy formation models that generally underpredict the observed abundance of high-z galaxies. In this paper we interpret these results in the light of a physically grounded model for the evolution of spheroidal galaxies. The model accurately reproduces the measured redshift distribution of galaxies without any adjustment of the parameters. The data do not support the indications of an excess of z > 4 dust…
We present the results of our search for high-redshift Lyman-break galaxies over the GOODS-South field. We use HST-ACS data in B, V, i' & z', VLT-ISAAC J and Ks, Spitzer-IRAC 3.6, 4.5, 5.8 and 8.0 micron data in conjunction with the new HAWK-I Y-band science verification data to search for dropout galaxies in the redshift range 6<z<9. We survey ~119 arcmin^2 to Y_AB=25.7 (5sigma), of which 37.5 arcmin^2 reaches Y_AB=25.9. Candidate z' and Y drop-outs were selected on the basis of a colour cut of (Y-J)_{AB}>0.75 mag and (z'-Y)_{AB}>1.0 mag respectively. We find no robust Y-drops (z~9) brighter …
The relation between the ratio of infrared (IR) and ultraviolet (UV) flux densities (the infrared excess: IRX) and the slope of the UV spectrum (β) of galaxies plays a fundamental role in the evaluation of the dust attenuation of star forming galaxies especially at high redshifts. Many authors, however, pointed out that there is a significant dispersion and/or deviation from the originally proposed IRX-βrelation depending on sample selection. We reexamined the IRX-βrelation by measuring the far- and near-UV flux densities of the original sample galaxies with GALEX and AKARI imaging data, and c…
We present Spitzer 16 micron imaging of the Great Observatories Origins Deep Survey (GOODS) fields. We survey 150 square arcminutes in each of the two GOODS fields (North and South), to an average 3 sigma depth of 40 and 65 micro-Jy respectively. We detect about 1300 sources in both fields combined. We validate the photometry using the 3-24 micron spectral energy distribution of stars in the fields compared to Spitzer spectroscopic templates. Comparison with ISOCAM and AKARI observations in the same fields show reasonable agreement, though the uncertainties are large. We provide a catalog of p…
Star-forming galaxies display a close relation among stellar mass, metallicity and star-formation rate (or molecular-gas mass). This is known as the fundamental metallicity relation (FMR) (or molecular-gas FMR), and it has a profound implication on models of galaxy evolution. However, there still remains a significant residual scatter around the FMR. We show here that a fourth parameter, the surface density of stellar mass, reduces the dispersion around the molecular-gas FMR. In a principal component analysis of 29 physical parameters of 41,338 star-forming galaxies, the surface density of ste…
Wide-field surveys are a commonly-used method for studying thousands of objects simultaneously, to investigate, e.g., the joint evolution of star-forming galaxies and active galactic nuclei. VLBI observations can yield valuable input to such studies because they are able to identify AGN. However, VLBI observations of large swaths of the sky are impractical using standard methods, because the fields of view of VLBI observations are of the order of 10" or less. We have embarked on a project to carry out Very Long Baseline Array (VLBA) observations of all 96 known radio sources in one of the best…
ABRIDGED-This paper presents the first direct estimate of the 3D clustering properties of far-infrared sources up to z~3. This has been possible thanks to the Pacs Evolutionary Probe (PEP) survey of the GOODS South field performed with the PACS instrument onboard the Herschel Satellite. An analysis of the two-point correlation function over the whole redshift range spanned by the data reports for the correlation length, r_0~6.3 Mpc and r_0~6.7 Mpc, respectively at 100um and 160um, corresponding to dark matter halo masses M>~10^{12.4} M_sun. Objects at z~2 instead seem to be more strongly clust…
Far-ultraviolet (FUV) and far-infrared (FIR) luminosity functions (LFs) of galaxies show a strong evolution from $z = 0$ to $z = 1$, but the FIR LF evolves much stronger than the FUV one. The FUV is dominantly radiated from newly formed short-lived OB stars, while the FIR is emitted by dust grains heated by the FUV radiation field. It is known that dust is always associated with star formation activity. Thus, both FUV and FIR are tightly related to the star formation in galaxies, but in a very complicated manner. In order to disentangle the relation between FUV and FIR emissions, we estimate t…
We use data from the first 100 square-degree field observed by the South Pole Telescope (SPT) in 2008 to measure the angular power spectrum of temperature anisotropies contributed by the background of dusty star-forming galaxies (DSFGs) at millimeter wavelengths. From the auto and cross-correlation of 150 and 220 GHz SPT maps, we significantly detect both Poisson distributed and, for the first time at millimeter wavelengths, clustered components of power from a background of DSFGs. The spectral indices between 150 and 220 GHz of the Poisson and clustered components are found to be 3.86 +- 0.23…
Using the 330hr ESO-MPG 870-micron survey of the Extended Chandra Deep Field South (ECDF-S) obtained with the Large Apex BOlometer CAmera (LABOCA) on the Atacama Pathfinder EXperiment (APEX), we have carried out a stacking analysis at submillimeter (submm) wavelengths of a sample of 8266 near-infra-red (near-IR) selected (K_vega <= 20) galaxies, including 893 BzK galaxies, 1253 extremely red objects (EROs) and 737 distant red galaxies (DRGs), selected from the Multi-wavelength Survey by Yale-Chile (MUSYC). We measure average 870-micron fluxes of 0.20+-0.01mJy (20.0sigma), 0.45+-0.04mJy (11.3si…
We probe star formation in the environments of massive $\sim10^{13}\,M_{\odot}$ dark matter halos at redshifts of $z$$\sim$$1$. This star formation is linked to a sub-millimetre clustering signal which we detect in maps of the Planck High Frequency Instrument that are stacked at the positions of a sample of high-redshift ($z$$>$$2$) strongly-lensed dusty star-forming galaxies (DSFGs) selected from the South Pole Telescope (SPT) 2500 deg$^2$ survey. The clustering signal has sub-millimetre colours which are consistent with the mean redshift of the foreground lensing halos ($z$$\sim$$1$). We rep…
We present the evolutionary properties and luminosity functions of the radio sources belonging to the Chandra Deep Field South VLA survey, which reaches a flux density limit at 1.4 GHz of 43 microJy at the field center and redshift ~5, and which includes the first radio-selected complete sample of radio-quiet active galactic nuclei (AGN). We use a new, comprehensive classification scheme based on radio, far- and near-IR, optical, and X-ray data to disentangle star-forming galaxies from AGN and radio-quiet from radio-loud AGN. We confirm our previous result that star-forming galaxies become dom…
[abridged] The ALESS survey has followed-up a sample of 122 sub-millimeter sources in the Extended Chandra Deep Field South at 870um with ALMA, allowing to pinpoint the positions of sub-millimeter galaxies (SMGs) to 0.3'' and to find their precise counterparts at different wavelengths. This enabled the first compilation of the multi-wavelength spectral energy distributions (SEDs) of a statistically reliable survey of SMGs. In this paper, we present a new calibration of the MAGPHYS modelling code that is optimized to fit these UV-to-radio SEDs of z>1 star-forming galaxies using an energy balanc…
We present ALMA observations on and around the radio-quiet quasar UM287 at $z=2.28$. Together with a companion quasar, UM287 is believed to play a major role in powering the surrounding enormous Ly$α$ nebula (ELAN), dubbed the Slug ELAN, that has an end-to-end size of 450 physical kpc. In addition to the quasars, we detect a new dusty star-forming galaxy (DSFG), dubbed the Slug-DSFG, in 2 mm continuum with a single emission line consistent with CO(4-3). The Slug-DSFG sits at a projected distance of 100 kpc south-east from UM287, with a systemic velocity difference of $-360\pm30$ km s$^{-1}$ wi…
