Search

Because of their limited angular resolution, far-infrared telescopes are usually affected by confusion phenomenon. Since several galaxies can be located in the same instrumental beam, only the brightest objects emerge from the fluctuations caused by fainter sources. The probe far-infrared mission for astrophysics imager (PRIMAger) will observe the mid- and far-infrared (25-235 $\mu$m) sky both in intensity and polarization. We aim to provide predictions of the confusion level and its consequences for future surveys. We produced simulated PRIMAger maps affected only by the confusion noise using the simulated infrared extragalactic sky (SIDES) semi-empirical simulation. We then estimated the confusion limit in these maps and extracted the sources using a basic blind extractor. By comparing the input galaxy catalog and the extracted source catalog, we derived various performance metrics as completeness, purity, and the accuracy of various measurements. In intensity, we predict that the confusion limit increases rapidly with increasing wavelength. The confusion limit in polarization is more than 100x lower. The measured flux density is dominated by the brightest galaxy in the beam, but other objects also contribute at longer wavelength (~30% at 235 $\mu$m). We also show that galaxy clustering has a mild impact on confusion in intensity (up to 25%), while it is negligible in polarization. In intensity, a basic blind extraction will be sufficient to detect galaxies at the knee of the luminosity function up to z~3 and 10$^{11}$ M$_\odot$ main-sequence galaxies up to z~5. In polarization for the baseline sensitivity, we expect ~8 000 detections up to z=2.5 opening a totally new window on the high-z dust polarization. Finally, we show that intensity surveys at short wavelength and polarization surveys at long wavelength tend to reach confusion at similar depth. There is thus a strong synergy., Comment: 21 pages, 15 figures, 4 tables, submitted to A&A

We present a Bayesian inference method to characterise the dust emission properties using the well-known dust-HI correlation in the diffuse interstellar medium at Planck frequencies $\nu \ge 217$ GHz. We use the Galactic HI map from the Galactic All-Sky Survey (GASS) as a template to trace the Galactic dust emission. We jointly infer the pixel-dependent dust emissivity and the zero level present in the Planck intensity maps. We use the Hamiltonian Monte Carlo technique to sample the multi-dimensional parameter space. We demonstrate that the methodology is unbiased when applied to realistic Planck sky simulations over a 7500 deg$^2$ area around the Southern Galactic pole. As an application on data, we analyse the Planck intensity map at 353 GHz to jointly infer the pixel-dependent dust emissivity at Nside=32 resolution (1.8\deg\ pixel size) and the global offset. We find that the spatially varying dust emissivity has a mean of 0.031 $MJysr^{-1} (10^{20} cm^{-2})^{-1}$ and $1\sigma$ standard deviation of 0.007 $MJysr^{-1} (10^{20} cm^{-2})^{-1}$. The mean dust emissivity increases monotonically with increasing mean HI column density. We find that the inferred global offset is consistent with the expected level of Cosmic Infrared Background (CIB) monopole added to the Planck data at 353 GHz. This method is useful in studying the line-of-sight variations of dust spectral energy distribution in the multi-phase interstellar medium., Comment: Submitted to MNRAS(MN-23-3956-MJ)

The low brightness dust emission at high Galactic latitude is of interest to study the interplay between physical processes in shaping the structure of the interstellar medium (ISM), as well as to statistically characterize dust emission as a foreground to the Cosmic Microwave Background (CMB). Progress in this avenue of research have been hampered by the difficulty of separating the dust emission from the Cosmic Infrared Background (CIB). We demonstrate that dust and CIB may be effectively separated based on their different structure on the sky and use the separation to characterize the structure of diffuse dust emission on angular scales where CIB is a significant component in terms of power. We use scattering transform statistics, the Wavelet Phase Harmonics (WPH), to perform a statistical component separation using Herschel SPIRE observations. This component separation is done only from observational data using non-Gaussian properties as a lever arm, and is done at a single 250 microns frequency. This method, that we validate on mock data, gives us access to non-Gaussian statistics of the interstellar dust and an output dust map essentially free from CIB contamination. Our statistical modelling characterizes the non-Gaussian structure of the diffuse ISM down to the smallest scales observed by Herschel. We recover the power-law shape of the dust power spectrum up to a wavenumber of 2 arcmin$^{-1}$ where the dust signal represents 2 percent of the total power. The output dust map reveals coherent structures at the smallest scales which were hidden by the CIB anisotropies. It opens new observational perspectives on the formation of structure in the diffuse ISM which we discuss with reference to past work. We have succeeded to perform a statistical separation from observational data only at a single frequency by using non-Gaussian statistics., Comment: Accepted in A&A on October 23, 2023

We present the early science results from a blind search of the extragalactic HI 21-cm absorption lines at z $\leqslant$ 0.09 with the drift-scan observation of the Five-hundred-meter Aperture Spherical radio Telescope (FAST). We carried out the search using the data collected in 643.8 hours by the ongoing Commensal Radio Astronomy FasT Survey (CRAFTS), which spans a sky area of 3155 deg$^{2}$ and covers 44827 radio sources with a flux density greater than 12 mJy. Due to the radio frequency interference (RFI), only the relatively clean data in the frequency range of 1.3-1.45 GHz are used in the present work. Under the assumption of $T_{s}/c_{f}$ = 100 K, the total completeness-corrected comoving absorption path length spanned by our data and sensitive to Damped Lyman $\alpha$ Absorbers (DLAs) are $\Delta X^{inv}$ = 8.33$\times10^3$ ($\Delta z^{inv} = 7.81\times10^{3}$) for intervening absorption. For associated absorption, the corresponding values are $\Delta X^{asc}$ = 12.8 ($\Delta z^{asc} = 11.9$). Three known HI absorbers (UGC 00613, 3C 293 and 4C +27.14) and two new HI absorbers (towards NVSS J231240-052547 and NVSS J053118+315412) are detected blindly. We fit the HI profiles with multi-components Gaussian functions and calculate the redshift (0.063, 0.066), width, flux density, optical depth and HI column densities for each absorption. Our results demonstrate the power of FAST in blindly searching HI absorbers. For absorption towards NVSS J231240-052547, the optical counterparts are faint and currently lack existing spectra. The most likely interpretation is that a radio-loud active galactic nucleus (AGN) is faint in the optical as the background source, with a faint optical absorber in between. NVSS J053118+315412 exhibits an associated absorption with a complex profile, which may suggest unsettled gas structures or gas accretion onto the supermassive black hole (SMBH)., Comment: 18 pages, 19 figures

High resolution cosmic microwave background (CMB) experiments have allowed us to precisely measure the CMB temperature power spectrum down to very small scales (multipole $\ell \sim 3000$). Such measurements at multiple frequencies enable separating the primary CMB anisotropies with other signals like CMB lensing, thermal and kinematic Sunyaev-Zel'dovich effects (tSZ and kSZ), and cosmic infrared background (CIB). In this paper, we explore another signal of interest at these frequencies that should be present in the CMB maps: extragalactic CO molecular rotational line emissions, which are the most widely used tracers of molecular gas in the line intensity mapping experiments. Using the SIDES simulations adopted for top hat bandpasses at 150 and 220 GHz, we show that the cross-correlation of the CIB with CO lines has a contribution similar to the CIB-tSZ correlation and the kSZ power, thereby contributing a non-negligible amount to the total power at these scales. This signal, therefore, may significantly impact the recently reported $\geq 3\sigma$ detection of the kSZ power spectrum from the South Pole Telescope (SPT) collaboration, as the contribution of the CO lines is not considered in such analyses. Our results also provide a new way of measuring the CO power spectrum in cross-correlation with the CIB. Finally, these results show that the CO emissions present in the CMB maps will have to be accounted for in all the CMB auto-power spectrum and cross-correlation studies involving a LSS tracer., Comment: 8 pages main text and bibliography + 2 pages appendices, 6 figures. Comments very welcome

CONCERTO (CarbON CII line in post-rEionization and ReionizaTiOn) is a low-resolution Fourier transform spectrometer dedicated to the study of star-forming galaxies and clusters of galaxies in the transparent millimeter windows from the ground. It is characterized by a wide instantaneous 18.6 arcmin field of view, operates at 130-310 GHz, and was installed on the 12-meter Atacama Pathfinder Experiment (APEX) telescope at 5100 m above sea level. CONCERTO's double focal planes host two arrays of 2152 kinetic inductance detectors and represent a pioneering instrument to meet a state-of-the-art scientific challenge. This paper introduces the CONCERTO instrument and explains its status, shows the first CONCERTO spectral maps of Orion, and describes the perspectives of the project., Comment: 6 pages, 2 figures, to appear in Proc. of the mm Universe 2023 conference, Grenoble (France), June 2023, published by F. Mayet et al. (Eds), EPJ Web of conferences, EDP Sciences

Our current understanding of the cosmic star formation history at z>3 is primarily based on UV-selected galaxies (i.e., LBGs). Recent studies of H-dropouts have revealed that we may be missing a large proportion of star formation that is taking place in massive galaxies at z>3. In this work, we extend the H-dropout criterion to lower masses to select optically dark/faint galaxies (OFGs), in order to complete the census between LBGs and H-dropouts. Our criterion (H> 26.5 mag & [4.5] < 25 mag) combined with a de-blending technique is designed to select not only extremely dust-obscured massive galaxies but also normal star-forming galaxies. In total, we identified 27 OFGs at z_phot > 3 (z_med=4.1) in the GOODS-ALMA field, covering a wide distribution of stellar masses with log($M_{\star}$/$M_{\odot}$) = 9.4-11.1. We find that up to 75% of the OFGs with log($M_{\star}$/$M_{\odot}$) = 9.5-10.5 were neglected by previous LBGs and H-dropout selection techniques. After performing stacking analyses, the OFGs exhibit shorter gas depletion timescales, slightly lower gas fractions, and lower dust temperatures than typical star-forming galaxies. Their SFR_tot (SFR_ IR+SFR_UV) is much larger than SFR_UVcorr (corrected for dust extinction), with SFR_tot/SFR_UVcorr = $8\pm1$, suggesting the presence of hidden dust regions in the OFGs that absorb all UV photons. The average dust size measured by a circular Gaussian model fit is R_e(1.13 mm)=1.01$\pm$0.05 kpc. We find that the cosmic SFRD at z>3 contributed by massive OFGs is at least two orders of magnitude higher than the one contributed by equivalently massive LBGs. Finally, we calculate the combined contribution of OFGs and LBGs to the cosmic SFRD at z=4-5 to be 4 $\times$ 10$^{-2}$ $M_{\odot}$ yr$^{-1}$Mpc$^{-3}$, which is about 0.15 dex (43%) higher than the SFRD derived from UV-selected samples alone at the same redshift., Comment: 26 pages, 14 figures, 8 tables. Accepted for publication in A&A

CarbON CII line in post-rEionization and ReionizaTiOn (CONCERTO) is a low-resolution spectrometer with an instantaneous field-of-view of 18.6 arcmin, operating in the 130-310 GHz transparent atmospheric window. It is installed on the 12-meter Atacama Pathfinder Experiment (APEX) telescope at 5100 m above sea level. The Fourier transform spectrometer (FTS) contains two focal planes hosting a total of 4304 kinetic inductance detectors. The FTS interferometric pattern is recorded on the fly while continuously scanning the sky. One of the goals of CONCERTO is to characterize the large-scale structure of the Universe by observing the integrated emission from unresolved galaxies. This methodology is an innovative technique and is called line intensity mapping. In this paper, we describe the CONCERTO instrument, the effect of the vibration of the FTS beamsplitter, and the status of the CONCERTO main survey., Comment: 9 pages, 7 figures, to appear in the Proceedings of SPIE Astronomical Telescopes + Instrumentation 2022

We describe the on-line algorithms developed to probe Lumped Element Kinetic Inductance Detectors (LEKID) in this paper. LEKIDs are millimeter wavelength detectors for astronomy. LEKID arrays are currently operated in different instruments as: NIKA2 at the IRAM telescope in Spain, KISS at the Teide Observatory telescope in Tenerife, and CONCERTO at the APEX 12-meter telescope in Chile. LEKIDs are superconducting microwave resonators able to detect the incoming light at millimeter wavelengths and they are well adapted for frequency multiplexing (currently up to 360 pixels on a single microwave guide). Nevertheless, their use for astronomical observations requires specific readout and acquisition systems both to deal with the instrumental and multiplexing complexity, and to adapt to the observational requirements (e.g. fast sampling rate, background variations, on-line calibration, photometric accuracy, etc). This paper presents the different steps of treatment from identifying the resonance frequency of each LEKID to the continuous automatic control of drifting LEKID resonance frequencies induced by background variations.

We investigate the 1/f noise of the Five-hundred-meter Aperture Spherical Telescope (FAST) receiver system using drift-scan data from an intensity mapping pilot survey. All the 19 beams have 1/f fluctuations with similar structures. Both the temporal and the 2D power spectrum densities are estimated. The correlations directly seen in the time series data at low frequency $f$ are associated with the sky signal, perhaps due to a coupling between the foreground and the system response. We use Singular Value Decomposition (SVD) to subtract the foreground. By removing the strongest components, the measured 1/f noise power can be reduced significantly. With 20 modes subtraction, the knee frequency of the 1/f noise in a 10 MHz band is reduced to $1.8 \times 10^{-3}\Hz$, well below the thermal noise over 500-seconds time scale. The 2D power spectra show that the 1/f-type variations are restricted to a small region in the time-frequency space and the correlations in frequency can be suppressed with SVD modes subtraction. The residual 1/f noise after the SVD mode subtraction is uncorrelated in frequency, and a simple noise diode frequency-independent calibration of the receiver gain at 8s interval does not affect the results. The 1/f noise can be important for HI intensity mapping, we estimate that the 1/f noise has a knee frequency $(f_{k}) \sim$ 6 $\times$ 10$^{-4}$Hz, and time and frequency correlation spectral indices $(\alpha) \sim 0.65$, $(\beta) \sim 0.8$ after the SVD subtraction of 30 modes. This can bias the HI power spectrum measurement by 10 percent., Comment: 13 pages,17 figures, MNRAS accepted

We investigate the 1/f noise of the Five-hundred-meter Aperture Spherical Telescope (FAST) receiver system using drift-scan data from an intensity mapping pilot survey. All the 19 beams have 1/f fluctuations with similar structures. Both the temporal and the 2D power spectrum densities are estimated. The correlations directly seen in the time series data at low frequency $f$ are associated with the sky signal, perhaps due to a coupling between the foreground and the system response. We use Singular Value Decomposition (SVD) to subtract the foreground. By removing the strongest components, the measured 1/f noise power can be reduced significantly. With 20 modes subtraction, the knee frequency of the 1/f noise in a 10 MHz band is reduced to $1.8 \times 10^{-3}\Hz$, well below the thermal noise over 500-seconds time scale. The 2D power spectra show that the 1/f-type variations are restricted to a small region in the time-frequency space and the correlations in frequency can be suppressed with SVD modes subtraction. The residual 1/f noise after the SVD mode subtraction is uncorrelated in frequency, and a simple noise diode frequency-independent calibration of the receiver gain at 8s interval does not affect the results. The 1/f noise can be important for HI intensity mapping, we estimate that the 1/f noise has a knee frequency $(f_{k}) \sim$ 6 $\times$ 10$^{-4}$Hz, and time and frequency correlation spectral indices $(\alpha) \sim 0.65$, $(\beta) \sim 0.8$ after the SVD subtraction of 30 modes. This can bias the HI power spectrum measurement by 10 percent., Comment: 13 pages,17 figures, MNRAS accepted

We present the first [C II] 158 mu m luminosity function (LF) at z similar to 5 from a sample of serendipitous lines detected in the ALMA Large Program to INvestigate [C II] at Early times (ALPINE). A study of the 118 ALPINE pointings revealed several serendipitous lines. Based on their fidelity, we selected 14 lines for the final catalog. According to the redshift of their counterparts, we identified eight out of 14 detections as [C II] lines at z similar to 5, along with two as CO transitions at lower redshifts. The remaining four lines have an elusive identification in the available catalogs and we considered them as [C II] candidates. We used the eight confirmed [C II] and the four [C II] candidates to build one of the first [C II] LFs at z similar to 5. We found that 11 out of these 12 sources have a redshift very similar to that of the ALPINE target in the same pointing, suggesting the presence of overdensities around the targets. Therefore, we split the sample in two (a "clustered" and "field" subsample) according to their redshift separation and built two separate LFs. Our estimates suggest that there could be an evolution of the [C II] LF between z similar to 5 and z similar to 0. By converting the [C II] luminosity to the star-formation rate, we evaluated the cosmic star-formation rate density (SFRD) at z similar to 5. The clustered sample results in a SFRD similar to 10 times higher than previous measurements from UV-selected galaxies. On the other hand, from the field sample (likely representing the average galaxy population), we derived a SFRD similar to 1.6 higher compared to current estimates from UV surveys but compatible within the errors. Because of the large uncertainties, observations of larger samples will be necessary to better constrain the SFRD at z similar to 5. This study represents one of the first efforts aimed at characterizing the demography of [C II] emitters at z similar to 5 using a mm selection of galaxies.

We present the first [C II] 158 mu m luminosity function (LF) at z similar to 5 from a sample of serendipitous lines detected in the ALMA Large Program to INvestigate [C II] at Early times (ALPINE). A study of the 118 ALPINE pointings revealed several serendipitous lines. Based on their fidelity, we selected 14 lines for the final catalog. According to the redshift of their counterparts, we identified eight out of 14 detections as [C II] lines at z similar to 5, along with two as CO transitions at lower redshifts. The remaining four lines have an elusive identification in the available catalogs and we considered them as [C II] candidates. We used the eight confirmed [C II] and the four [C II] candidates to build one of the first [C II] LFs at z similar to 5. We found that 11 out of these 12 sources have a redshift very similar to that of the ALPINE target in the same pointing, suggesting the presence of overdensities around the targets. Therefore, we split the sample in two (a "clustered" and "field" subsample) according to their redshift separation and built two separate LFs. Our estimates suggest that there could be an evolution of the [C II] LF between z similar to 5 and z similar to 0. By converting the [C II] luminosity to the star-formation rate, we evaluated the cosmic star-formation rate density (SFRD) at z similar to 5. The clustered sample results in a SFRD similar to 10 times higher than previous measurements from UV-selected galaxies. On the other hand, from the field sample (likely representing the average galaxy population), we derived a SFRD similar to 1.6 higher compared to current estimates from UV surveys but compatible within the errors. Because of the large uncertainties, observations of larger samples will be necessary to better constrain the SFRD at z similar to 5. This study represents one of the first efforts aimed at characterizing the demography of [C II] emitters at z similar to 5 using a mm selection of galaxies.

We present the first [CII] 158 $\mu$m luminosity function (LF) at $z\sim 5$ from a sample of serendipitous lines detected in the ALMA Large Program to INvestigate [CII] at Early times (ALPINE). A search performed over the 118 ALPINE pointings revealed several serendipitous lines. Based on their fidelity, we selected 14 lines for the final catalog. According to the redshift of their counterparts, we identified 8 out of 14 detections as [CII] lines at $z\sim 5$, and two as CO transitions at lower redshifts. The remaining 4 lines have an elusive identification in the available catalogs and we considered them as [CII] candidates. We used the 8 confirmed [CII] and the 4 [CII] candidates to build one of the first [CII] LFs at $z\sim 5$. We found that 11 out of these 12 sources have a redshift very similar to that of the ALPINE target in the same pointing, suggesting the presence of overdensities around the targets. Therefore, we split the sample in two (a "clustered" and "field" sub-sample) according to their redshift separation and built two separate LFs. Our estimates suggest that there could be an evolution of the [CII] LF between $z \sim 5$ and $z \sim 0$. By converting the [CII] luminosity to star formation rate we evaluated the cosmic star formation rate density (SFRD) at $z\sim 5$. The clustered sample results in a SFRD $\sim 10$ times higher than previous measurements from UV-selected galaxies. On the other hand, from the field sample (likely representing the average galaxy population) we derived a SFRD $\sim 1.6$ higher compared to current estimates from UV surveys but compatible within the errors. Because of the large uncertainties, observations of larger samples are necessary to better constrain the SFRD at $z\sim 5$. This study represents one of the first efforts aimed at characterizing the demography of [CII] emitters at $z\sim 5$ using a mm-selection of galaxies., Comment: 19 pages, 12 figures; submitted to Astronomy & Astrophysics

Understanding the formation and evolution of galaxies over cosmic time is one of the foremost goals of astrophysics and cosmology today. The cosmic star formation rate has undergone a dramatic evolution over the course of the last 14 billion years, and dust obscured star forming galaxies (DSFGs) are a crucial component of this evolution. A variety of important, bright, and unextincted diagnostic lines are present in the far-infrared (FIR) which can provide crucial insight into the physical conditions of galaxy evolution, including the instantaneous star formation rate, the effect of AGN feedback on star formation, the mass function of the stars, metallicities, and the spectrum of their ionizing radiation. FIR spectroscopy is technically difficult but scientifically crucial. Stratospheric balloons offer a platform which can outperform current instrument sensitivities and are the only way to provide large-area, wide bandwidth spatial/spectral mapping at FIR wavelengths. NASA recently selected TIM, the Terahertz Intensity Mapper, with the goal of demonstrating the key technical milestones necessary for FIR spectroscopy. The TIM instrument consists of an integral-field spectrometer from 240-420 microns with 3600 kinetic-inductance detectors (KIDs) coupled to a 2-meter low-emissivity carbon fiber telescope. In this paper, we will summarize plans for the TIM experiment's development, test and deployment for a planned flight from Antarctica., Comment: 8 pages, 5 figures, published in the 30th International Symposium on Space THz Technology (ISSTT2019), Gothenburg, Sweden, April 15-17, 2019

We present the first [CII] 158 $\mu$m luminosity function (LF) at $z\sim 5$ from a sample of serendipitous lines detected in the ALMA Large Program to INvestigate [CII] at Early times (ALPINE). A search performed over the 118 ALPINE pointings revealed several serendipitous lines. Based on their fidelity, we selected 14 lines for the final catalog. According to the redshift of their counterparts, we identified 8 out of 14 detections as [CII] lines at $z\sim 5$, and two as CO transitions at lower redshifts. The remaining 4 lines have an elusive identification in the available catalogs and we considered them as [CII] candidates. We used the 8 confirmed [CII] and the 4 [CII] candidates to build one of the first [CII] LFs at $z\sim 5$. We found that 11 out of these 12 sources have a redshift very similar to that of the ALPINE target in the same pointing, suggesting the presence of overdensities around the targets. Therefore, we split the sample in two (a "clustered" and "field" sub-sample) according to their redshift separation and built two separate LFs. Our estimates suggest that there could be an evolution of the [CII] LF between $z \sim 5$ and $z \sim 0$. By converting the [CII] luminosity to star formation rate we evaluated the cosmic star formation rate density (SFRD) at $z\sim 5$. The clustered sample results in a SFRD $\sim 10$ times higher than previous measurements from UV-selected galaxies. On the other hand, from the field sample (likely representing the average galaxy population) we derived a SFRD $\sim 1.6$ higher compared to current estimates from UV surveys but compatible within the errors. Because of the large uncertainties, observations of larger samples are necessary to better constrain the SFRD at $z\sim 5$. This study represents one of the first efforts aimed at characterizing the demography of [CII] emitters at $z\sim 5$ using a mm-selection of galaxies., Comment: 19 pages, 12 figures; submitted to Astronomy & Astrophysics

The characterization of the Intracluster Medium (ICM) properties of high-redshift galaxy clusters is fundamental to our understanding of large-scale structure formation processes. We present the results of a multiwavelength analysis of the very massive cluster MOO J1142+1527 at a redshift z = 1.2 discovered as part of the Massive and Distant Clusters of WISE Survey. This analysis is based on high angular resolution Chandra X-ray and NIKA2 Sunyaev-Zel'dovich (SZ) data. The cluster thermodynamic radial profiles have been obtained with unprecedented precision at this redshift and up to 0.7R , thanks to the combination of high-resolution X-ray and SZ data. The comparison between the galaxy distribution mapped in infrared by Spitzer and the morphological properties of the ICM derived from the combined analysis of the Chandra and NIKA2 data leads us to the conclusion that the cluster is an ongoing merger. We have estimated a systematic uncertainty on the cluster total mass that characterizes both the impact of the observed deviations from spherical symmetry and of the core dynamics on the mass profile. We further combine the X-ray and SZ data at the pixel level to obtain maps of the temperature and entropy distributions. We find a relatively low-entropy core at the position of the X-ray peak and high-temperature regions located on its south and west sides. This work demonstrates that the addition of spatially resolved SZ observations to low signal-to-noise X-ray data brings a high information gain on the characterization of the evolution of ICM thermodynamic properties at z > 1.

Mapping millimetre continuum emission has become a key issue in modern multi-wavelength astrophysics. In particular, spectrum imaging at low-frequency resolution is an asset for characterising the clusters of galaxies via the Sunyaev–Zel’dovich effect. In this context, we have built a ground-based spectrum-imager named KIDs Interferometer Spectrum Survey (KISS). This instrument is based on two 316-pixel arrays of Kinetic Inductance Detectors (KID) cooled to 150 mK by a custom dilution refrigerator-based cryostat. By using Ti–Al and Al absorbers, we can cover a wide frequency range between 80 and 300 GHz. In order to preserve a large instantaneous field of view ∼ 1 , the spectrometer is based on a Fourier transform interferometer. This represents a technological challenge due to the fast scanning speed that is needed to overcome the effects of background atmospheric fluctuations. KISS is installed at the QUIJOTE 2.25 m telescope in Tenerife since February 2019 and is currently in its commissioning phase. In this report, we present an overview of the instrument and the latest results.

High-mass clusters at low redshifts have been intensively studied at various wavelengths. However, while more distant objects at lower masses constitute the bulk population of future surveys, their physical state remain poorly explored to date. In this paper, we present resolved observations of the Sunyaev-Zel'dovich (SZ) effect, obtained with the NIKA2 camera, towards the cluster of galaxies XLSSC 102, a relatively low-mass system (M500 ∼ 2 × 1014 M·) at z = 0.97 detected from the XXL survey. We combine NIKA2 SZ data, XMM-Newton X-ray data, and Megacam optical data to explore, respectively, the spatial distribution of the gas electron pressure, the gas density, and the galaxies themselves. We find significant offsets between the X-ray peak, the SZ peak, the brightest cluster galaxy, and the peak of galaxy density. Additionally, the galaxy distribution and the gas present elongated morphologies. This is interpreted as the sign of a recent major merging event, which induced a local boost of the gas pressure towards the north of XLSSC 102 and stripped the gas out of the galaxy group. The NIKA2 data are also combined with XXL data to construct the thermodynamic profiles of XLSSC 102, obtaining relatively tight constraints up to about ∼r500, and revealing properties that are typical of disturbed systems. We also explore the impact of the cluster centre definition and the implication of local pressure substructure on the recovered profiles. Finally, we derive the global properties of XLSSC 102 and compare them to those of high-mass-and-low-redshift systems, finding no strong evidence for non-standard evolution. We also use scaling relations to obtain alternative mass estimates from our profiles. The variation between these different mass estimates reflects the difficulty to accurately measure the mass of low-mass clusters at z ∼ 1, especially with low signal-to-noise ratio data and for a disturbed system. However, it also highlights the strength of resolved SZ observatio

High-resolution mapping of the intracluster medium (ICM) up to high redshift and down to low masses is crucial to derive accurate mass estimates of the galaxy cluster and to understand the systematic eects aecting cosmological studies based on galaxy clusters. We present a spatially resolved Sunyaev-Zel'dovich (SZ)/X-ray analysis of ACT-CL J0215.4+0030, a high-redshift (z = 0:865) galaxy cluster of intermediate mass (M500 ' 3:5 1014 M) observed as part of the ongoing NIKA2 SZ large program, which is a follow-up of a representative sample of objects at 0:5 z 0:9. In addition to the faintness and small angular size induced by its mass and redshift, the cluster is contaminated by point sources that significantly aect the SZ signal. This is therefore an interesting case study for the most challenging sources of the NIKA2 cluster sample. We present the NIKA2 observations of this cluster and the resulting data.We identified the point sources that aect the NIKA2 maps of the cluster as submillimeter galaxies with counterparts in catalogs of sources constructed by the SPIRE instrument on board the Herschel observatory. We reconstructed the ICM pressure profile by performing a joint analysis of the SZ signal and of the point-source component in the NIKA2 150 GHz map. This cluster is a very weak source that lies below the selection limit of the Planck catalog. Nonetheless, we obtained high-quality estimates of the ICM thermodynamical properties with NIKA2. We compared the pressure profile extracted from the NIKA2 map to the pressure profile obtained from X-ray data alone by deprojecting the public XMM-Newton observations of the cluster.We combined the NIKA2 pressure profile with the X-ray deprojected density to extract detailed information on the ICM. The radial distribution of its thermodynamic properties (the pressure, temperature and entropy) indicate that the cluster has a highly disturbed core. We also computed the hydrostatic mass of the cluster, which is compatible with

Context. NIKA2 is a dual-band millimetre continuum camera of 2 900 kinetic inductance detectors, operating at 150 and 260 GHz, installed at the IRAM 30-m telescope in Spain. Open to the scientific community since October 2017, NIKA2 will provide key observations for the next decade to address a wide range of open questions in astrophysics and cosmology. Aims. Our aim is to present the calibration method and the performance assessment of NIKA2 after one year of observation. Methods. We used a large data set acquired between January 2017 and February 2018 including observations of primary and secondary calibrators and faint sources that span the whole range of observing elevations and atmospheric conditions encountered by the IRAM 30-m telescope. This allowed us to test the stability of the performance parameters against time evolution and observing conditions. We describe a standard calibration method, referred to as the "Baseline"method, to translate raw data into flux density measurements. This includes the determination of the detector positions in the sky, the selection of the detectors, the measurement of the beam pattern, the estimation of the atmospheric opacity, the calibration of absolute flux density scale, the flat fielding, and the photometry. We assessed the robustness of the performance results using the Baseline method against systematic effects by comparing results using alternative methods. Results. We report an instantaneous field of view of 6.5′ in diameter, filled with an average fraction of 84%, and 90% of valid detectors at 150 and 260 GHz, respectively. The beam pattern is characterised by a FWHM of 17.6″ ± 0.1″ and 11.1″ ± 0.2″, and a main-beam efficiency of 47%±3%, and 64%±3% at 150 and 260 GHz, respectively. The point-source rms calibration uncertainties are about 3% at 150 GHz and 6% at 260 GHz. This demonstrates the accuracy of the methods that we deployed to correct for atmospheric attenuation. The absolute calibration uncertainties are o

We probe star formation in the environments of massive (∼1013 M⊙) dark matter haloes at redshifts of z ∼ 1. This star formation is linked to a submillimetre 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 deg2 survey. The clustering signal has submillimetre colours which are consistent with the mean redshift of the foreground lensing haloes (z ∼ 1). We report a mean excess of star formation rate (SFR) compared to the field, of (2700 ± 700) M⊙ yr−1 from all galaxies contributing to this clustering signal within a radius of 3.5 arcmin from the SPT DSFGs. The magnitude of the Planck excess is in broad agreement with predictions of a current model of the cosmic infrared background. The model predicts that 80 per cent of the excess emission measured by Planck originates from galaxies lying in the neighbouring haloes of the lensing halo. Using Herschel maps of the same fields, we find a clear excess, relative to the field, of individual sources which contribute to the Planck excess. The mean excess SFR compared to the field is measured to be (370 ± 40) M⊙ yr−1 per resolved, clustered source. Our findings suggest that the environments around these massive z ∼ 1 lensing haloes host intense star formation out to about 2 Mpc. The flux enhancement due to clustering should also be considered when measuring flux densities of galaxies in Planck data.

This paper discusses the science case for a sensitive spectro-polarimetric survey of the microwave sky. Such a survey would provide a tomographic and dynamic census of the three-dimensional distribution of hot gas, velocity flows, early metals, dust, and mass distribution in the entire Hubble volume, exploit CMB temperature and polarisation anisotropies down to fundamental limits, and track energy injection and absorption into the radiation background across cosmic times by measuring spectral distortions of the CMB blackbody emission. In addition to its exceptional capability for cosmology and fundamental physics, such a survey would provide an unprecedented view of microwave emissions at sub-arcminute to few-arcminute angular resolution in hundreds of frequency channels, a data set that would be of immense legacy value for many branches of astrophysics. We propose that this survey be carried-out with a large space mission featuring a broad-band polarised imager and a moderate resolution spectro-imager at the focus of a 3.5m aperture telescope actively cooled to about 8K, complemented with absolutely-calibrated Fourier Transform Spectrometer modules observing at degree-scale angular resolution in the 10-2000 GHz frequency range. We propose two observing modes: a survey mode to map the entire sky as well as a few selected wide fields, and an observatory mode for deeper observations of regions of specific interest., Comment: 20 pages, white paper submitted in answer to the "Voyage 2050" call to prepare the long term plan in the ESA science programme

The cosmic infrared background (CIB) is a powerful probe of large-scale structure across a very large redshift range, and consists of unresolved redshifted infrared emission from dusty galaxies. It can be used to study the astrophysics of galaxies, the star formation history of the universe, and the connection between dark and luminous matter. It can furthermore be used as a tracer of the large-scale structure and thus assist in de-lensing of the cosmic microwave background. The major difficulty in its use lies in obtaining accurate and unbiased large-scale CIB images that are cleaned of the contamination by Galactic dust. We used data on neutral atomic hydrogen from the recently-released HI4PI Survey to create template maps of Galactic dust, allowing us to remove this component from the Planck intensity maps from 353 to 857 GHz for approximately $25\%$ of the sky. This allows us to constrain the CIB power spectrum down to $\ell\gtrsim 70$. We present these CIB maps and the various processing and validation steps that we have performed to ensure their quality, as well as a comparison with previous studies. All our data products are made publicly available at https://doi.org/10.7910/DVN/8A1SR3, thereby enabling the community to investigate a wide range of questions related to the universe's large-scale structure., Comment: 23 pages, 25 figures. Comments welcome!

The Cosmic Dawn and Reionization epochs remain a fundamental but challenging frontier of astrophysics and cosmology. We advocate a large-scale, multi-tracer approach to develop a comprehensive understanding of the physics that led to the formation and evolution of the first stars and galaxies. We highlight the line intensity mapping technique to trace the multi-phase reionization topology on large scales, and measure reionization history in detail. Besides 21cm, we advocate for Lya tomography mapping during the epoch of Wouthuysen-Field coupling as an additional probe of the cosmic dawn era., Comment: Astro2020 Science White Paper; 5 pages, 1 figure

The Cosmic Dawn and Reionization epochs remain a fundamental but challenging frontier of astrophysics and cosmology. We advocate a large-scale, multi-tracer approach to develop a comprehensive understanding of the physics that led to the formation and evolution of the first stars and galaxies. We highlight the line intensity mapping technique to trace the multi-phase reionization topology on large scales, and measure reionization history in detail. Besides 21cm, we advocate for Lya tomography mapping during the epoch of Wouthuysen-Field coupling as an additional probe of the cosmic dawn era.

The cosmic infrared background (CIB) is a powerful probe of large-scale structure across a very large redshift range, and consists of unresolved redshifted infrared emission from dusty galaxies. It can be used to study the astrophysics of galaxies, the star formation history of the universe, and the connection between dark and luminous matter. It can furthermore be used as a tracer of the large-scale structure and thus assist in de-lensing of the cosmic microwave background. The major difficulty in its use lies in obtaining accurate and unbiased large-scale CIB images that are cleaned of the contamination by Galactic dust. We used data on neutral atomic hydrogen from the recently-released HI4PI Survey to create template maps of Galactic dust, allowing us to remove this component from the Planck intensity maps from 353 to 857 GHz for approximately $25\%$ of the sky. This allows us to constrain the CIB power spectrum down to $\ell\gtrsim 70$. We present these CIB maps and the various processing and validation steps that we have performed to ensure their quality, as well as a comparison with previous studies. All our data products are made publicly available at https://doi.org/10.7910/DVN/8A1SR3, thereby enabling the community to investigate a wide range of questions related to the universe's large-scale structure., Comment: 23 pages, 25 figures. Comments welcome!

The Cosmic Dawn and Reionization epochs remain a fundamental but challenging frontier of astrophysics and cosmology. We advocate a large-scale, multi-tracer approach to develop a comprehensive understanding of the physics that led to the formation and evolution of the first stars and galaxies. We highlight the line intensity mapping technique to trace the multi-phase reionization topology on large scales, and measure reionization history in detail. Besides 21cm, we advocate for Lya tomography mapping during the epoch of Wouthuysen-Field coupling as an additional probe of the cosmic dawn era., Comment: Astro2020 Science White Paper; 5 pages, 1 figure

This paper discusses the science case for a sensitive spectro-polarimetric survey of the microwave sky. Such a survey would provide a tomographic and dynamic census of the three-dimensional distribution of hot gas, velocity flows, early metals, dust, and mass distribution in the entire Hubble volume, exploit CMB temperature and polarisation anisotropies down to fundamental limits, and track energy injection and absorption into the radiation background across cosmic times by measuring spectral distortions of the CMB blackbody emission. In addition to its exceptional capability for cosmology and fundamental physics, such a survey would provide an unprecedented view of microwave emissions at sub-arcminute to few-arcminute angular resolution in hundreds of frequency channels, a data set that would be of immense legacy value for many branches of astrophysics. We propose that this survey be carried-out with a large space mission featuring a broad-band polarised imager and a moderate resolution spectro-imager at the focus of a 3.5m aperture telescope actively cooled to about 8K, complemented with absolutely-calibrated Fourier Transform Spectrometer modules observing at degree-scale angular resolution in the 10-2000 GHz frequency range. We propose two observing modes: a survey mode to map the entire sky as well as a few selected wide fields, and an observatory mode for deeper observations of regions of specific interest., Comment: 20 pages, white paper submitted in answer to the "Voyage 2050" call to prepare the long term plan in the ESA science programme

Galaxy clusters at high redshift are key targets for understanding matter assembly in the early Universe, yet they are challenging to locate. A sample of >2000 high-z candidate structures has been found using Planck's all-sky submm maps, and a sub-set of 234 have been followed up with Herschel-SPIRE, which showed that the emission can be attributed to large overdensities of dusty star-forming galaxies. In order to resolve and characterise the individual galaxies we targeted the eight brightest SPIRE sources in the centre of the Planck peak PLCK G073.4-57.5 using ALMA at 1.3 mm, and complemented these observations with data from IRAC, WIRCam J,K, and SCUBA-2. We detected a total of 18 millimetre galaxies brighter than 0.3 mJy in 2.4 arcmin^2. The ALMA source density is 8-30 times higher than average background estimates and larger than seen in typical 'proto-cluster' fields. We were able to match all but one of the ALMA sources to a NIR counterpart. The most significant (four) SCUBA-2 sources are not included in the ALMA pointings, but we find an 8sigma stacking detection of the ALMA sources in the SCUBA-2 map at 850 um. We derive photo-z, L_IR, SFR, stellar mass, T_dust, M_dust for all of the ALMA galaxies; the photo-zs identify two groups each of five sources, at z~1.5 and 2.4. The two groups show two 'red sequences' (i.e. similar NIR [3.6]-[4.5] colours and different J-K colours). The majority of the ALMA-detected galaxies are on the SFR versus stellar mass main sequence, and half of the sample is more massive than the characteristic stellar mass at the corresponding redshift. Serendipitous CO line detections in two of the galaxies appear to match their photometric redshifts at z~1.54. We performed an analysis of star-formation efficiencies and CO- and mm-continuum-derived gas fractions of our ALMA sources, combined with a sample of 1

Observations of the high-redshift Universe using the 21 cm line of neutral hydrogen and complimentary emission lines from the first galaxies promise to open a new door for our understanding of the epoch of reionization. We present predictions for the [C II] 158-micron line and H I 21 cm emission from redshifts z=6--9 using high-dynamic-range cosmological simulations combined with semi-analytical models. We find that the CONCERTO experiment should be able to detect the large scale power spectrum of [C II] emission to redshifts of up to z=8 (signal-to-noise ratio ~ 1 at k = 0.1 h/cMpc with 1500 hr of integration). A Stage II experiment similar to CCAT-p should be able to detect [C II] from even higher redshifts to high significance for similar integration times (signal-to-noise ratio of ~50 at k = 0.2 h/cMpc at z=6--9). We study the possibility of combining such future [C II] measurements with 21 cm measurements using LOFAR and SKA to measure the [C II]-21cm cross power spectra, and find that a Stage II experiment should be able to measure the cross-power spectrum for k < 1 h/cMpc to signal-to-noise ratio of better than 10. We discuss the capability of such measurements to constrain astrophysical parameters relevant to reionization and show that a measurement of the [C II]-21cm cross power spectrum helps break the degeneracy between the mass and brightness of ionizing sources., Comment: 15 pages, 7 figures; accepted for publication in MNRAS

In the last decade, it has become clear that the dust-enshrouded star formation contributes significantly to early galaxy evolution. Detection of dust is therefore essential in determining the properties of galaxies in the high-redshift universe. This requires observations at the (sub-)millimeter wavelengths. Unfortunately, sensitivity and background confusion of single dish observations on the one hand, and mapping efficiency of interferometers on the other hand, pose unique challenges to observers. One promising route to overcome these difficulties is intensity mapping of fluctuations which exploits the confusion-limited regime and measures the collective light emission from all sources, including unresolved faint galaxies. We discuss in this contribution how 2D and 3D intensity mapping can measure the dusty star formation at high redshift, through the Cosmic Infrared Background (2D) and [CII] fine structure transition (3D) anisotropies., Comment: Invited talk for the IAU Symposium 333 "Peering towards Cosmic Dawn", Dubrovnik, October 2-6, 2017; to appear in the proceedings, eds. Vibor Jelic and Thijs van der Hulst [6 pages, 4 figures]

Galaxy clusters at high redshift are key targets for understanding matter assembly in the early Universe, yet they are challenging to locate. A sample of >2000 high-z candidate structures has been found using Planck's all-sky submm maps, and a sub-set of 234 have been followed up with Herschel-SPIRE, which showed that the emission can be attributed to large overdensities of dusty star-forming galaxies. In order to resolve and characterise the individual galaxies we targeted the eight brightest SPIRE sources in the centre of the Planck peak PLCK G073.4-57.5 using ALMA at 1.3 mm, and complemented these observations with data from IRAC, WIRCam J,K, and SCUBA-2. We detected a total of 18 millimetre galaxies brighter than 0.3 mJy in 2.4 arcmin^2. The ALMA source density is 8-30 times higher than average background estimates and larger than seen in typical 'proto-cluster' fields. We were able to match all but one of the ALMA sources to a NIR counterpart. The most significant (four) SCUBA-2 sources are not included in the ALMA pointings, but we find an 8sigma stacking detection of the ALMA sources in the SCUBA-2 map at 850 um. We derive photo-z, L_IR, SFR, stellar mass, T_dust, M_dust for all of the ALMA galaxies; the photo-zs identify two groups each of five sources, at z~1.5 and 2.4. The two groups show two 'red sequences' (i.e. similar NIR [3.6]-[4.5] colours and different J-K colours). The majority of the ALMA-detected galaxies are on the SFR versus stellar mass main sequence, and half of the sample is more massive than the characteristic stellar mass at the corresponding redshift. Serendipitous CO line detections in two of the galaxies appear to match their photometric redshifts at z~1.54. We performed an analysis of star-formation efficiencies and CO- and mm-continuum-derived gas fractions of our ALMA sources, combined with a sample of 1

Observations of the high-redshift Universe using the 21 cm line of neutral hydrogen and complimentary emission lines from the first galaxies promise to open a new door for our understanding of the epoch of reionization. We present predictions for the [C II] 158-micron line and H I 21 cm emission from redshifts z=6--9 using high-dynamic-range cosmological simulations combined with semi-analytical models. We find that the CONCERTO experiment should be able to detect the large scale power spectrum of [C II] emission to redshifts of up to z=8 (signal-to-noise ratio ~ 1 at k = 0.1 h/cMpc with 1500 hr of integration). A Stage II experiment similar to CCAT-p should be able to detect [C II] from even higher redshifts to high significance for similar integration times (signal-to-noise ratio of ~50 at k = 0.2 h/cMpc at z=6--9). We study the possibility of combining such future [C II] measurements with 21 cm measurements using LOFAR and SKA to measure the [C II]-21cm cross power spectra, and find that a Stage II experiment should be able to measure the cross-power spectrum for k < 1 h/cMpc to signal-to-noise ratio of better than 10. We discuss the capability of such measurements to constrain astrophysical parameters relevant to reionization and show that a measurement of the [C II]-21cm cross power spectrum helps break the degeneracy between the mass and brightness of ionizing sources., Comment: 15 pages, 7 figures; accepted for publication in MNRAS

In the last decade, it has become clear that the dust-enshrouded star formation contributes significantly to early galaxy evolution. Detection of dust is therefore essential in determining the properties of galaxies in the high-redshift universe. This requires observations at the (sub-)millimeter wavelengths. Unfortunately, sensitivity and background confusion of single dish observations on the one hand, and mapping efficiency of interferometers on the other hand, pose unique challenges to observers. One promising route to overcome these difficulties is intensity mapping of fluctuations which exploits the confusion-limited regime and measures the collective light emission from all sources, including unresolved faint galaxies. We discuss in this contribution how 2D and 3D intensity mapping can measure the dusty star formation at high redshift, through the Cosmic Infrared Background (2D) and [CII] fine structure transition (3D) anisotropies., Comment: Invited talk for the IAU Symposium 333 "Peering towards Cosmic Dawn", Dubrovnik, October 2-6, 2017; to appear in the proceedings, eds. Vibor Jelic and Thijs van der Hulst [6 pages, 4 figures]

Following the first two annual intensity mapping workshops at Stanford in March 2016 and Johns Hopkins in June 2017, we report on the recent advances in theory, instrumentation and observation that were presented in these meetings and some of the opportunities and challenges that were identified looking forward. With preliminary detections of CO, [CII], Lya and low-redshift 21cm, and a host of experiments set to go online in the next few years, the field is rapidly progressing on all fronts, with great anticipation for a flood of new exciting results. This current snapshot provides an efficient reference for experts in related fields and a useful resource for nonspecialists. We begin by introducing the concept of line-intensity mapping and then discuss the broad array of science goals that will be enabled, ranging from the history of star formation, reionization and galaxy evolution to measuring baryon acoustic oscillations at high redshift and constraining theories of dark matter, modified gravity and dark energy. After reviewing the first detections reported to date, we survey the experimental landscape, presenting the parameters and capabilities of relevant instruments such as COMAP, mmIMe, AIM-CO, CCAT-p, TIME, CONCERTO, CHIME, HIRAX, HERA, STARFIRE, MeerKAT/SKA and SPHEREx. Finally, we describe recent theoretical advances: different approaches to modeling line luminosity functions, several techniques to separate the desired signal from foregrounds, statistical methods to analyze the data, and frameworks to generate realistic intensity map simulations., Comment: 99 pages, 48 figures; Endorsement and any comments welcome; To be submitted to Physics Reports

Millimeter-wave continuum astronomy is today an indispensable tool for both general Astrophysics studies and Cosmology. General purpose, large field-of-view instruments are needed to map the sky at intermediate angular scales not accessible by the high-resolution interferometers and by the coarse angular resolution space-borne or ground-based surveys. These instruments have to be installed at the focal plane of the largest single-dish telescopes. In this context, we have constructed and deployed a multi-thousands pixels dual-band (150 and 260 GHz, respectively 2mm and 1.15mm wavelengths) camera to image an instantaneous field-of-view of 6.5arc-min and configurable to map the linear polarization at 260GHz. We are providing a detailed description of this instrument, named NIKA2 (New IRAM KID Arrays 2), in particular focusing on the cryogenics, the optics, the focal plane arrays based on Kinetic Inductance Detectors (KID) and the readout electronics. We are presenting the performance measured on the sky during the commissioning runs that took place between October 2015 and April 2017 at the 30-meter IRAM (Institut of Millimetric Radio Astronomy) telescope at Pico Veleta. NIKA2 has been successfully deployed and commissioned, performing in-line with the ambitious expectations. In particular, NIKA2 exhibits FWHM angular resolutions of around 11 and 17.5 arc-seconds at respectively 260 and 150GHz. The NEFD (Noise Equivalent Flux Densities) demonstrated on the maps are, at these two respective frequencies, 33 and 8 mJy*sqrt(s). A first successful science verification run has been achieved in April 2017. The instrument is currently offered to the astronomical community during the coming winter and will remain available for at least the next ten years., Comment: Accepted for publication on Astronomy & Astrophysics, in press

Follow-up observations at high-angular resolution of submillimeter galaxies showed that the single-dish sources are comprised of a blend of several galaxies. Consequently, number counts derived from low and high angular resolution observations are in disagreement. This demonstrates the importance of resolution effects and the need to have realistic simulations to explore them. We built a new 2deg^2 simulation of the extragalactic sky from the far-infrared to the submillimeter. It is based on an updated version of the two star-formation mode galaxy evolution model. Using global galaxy properties, we use the abundance matching technique to populate a dark-matter lightcone and thus simulate the clustering. We produce maps and extract the sources, and show that the limited angular resolution of single-dish instruments have a strong impact on (sub)millimeter continuum observations. Taking into account these resolution effects, we are reproducing a large set of observables, including number counts, redshift distributions, and cosmic infrared background power spectra. Our simulation describes consistently the number counts from single-dish telescopes and interferometers. In particular, at 350 and 500 um, we find that number counts measured by Herschel between 5 and 50 mJy are biased towards high values by a factor 2, and that redshift distributions are biased towards low z. We also show that the clustering has an important impact on the Herschel pixel histogram used to derive number counts from P(D) analysis. Finally, we demonstrate that the large number density of red Herschel sources found in observations but not in models could be an observational artifact caused by the combination of noise, resolution effects, and the steepness of color and flux density distributions. Our simulation (SIDES) is available at http://cesam.lam.fr/sides, Comment: 22 pages, 17 figures, version accepted by A&A (red source section significantly improved following the comments of the referee), simulated catalog available at http://cesam.lam.fr/sides

Following the first two annual intensity mapping workshops at Stanford in March 2016 and Johns Hopkins in June 2017, we report on the recent advances in theory, instrumentation and observation that were presented in these meetings and some of the opportunities and challenges that were identified looking forward. With preliminary detections of CO, [CII], Lya and low-redshift 21cm, and a host of experiments set to go online in the next few years, the field is rapidly progressing on all fronts, with great anticipation for a flood of new exciting results. This current snapshot provides an efficient reference for experts in related fields and a useful resource for nonspecialists. We begin by introducing the concept of line-intensity mapping and then discuss the broad array of science goals that will be enabled, ranging from the history of star formation, reionization and galaxy evolution to measuring baryon acoustic oscillations at high redshift and constraining theories of dark matter, modified gravity and dark energy. After reviewing the first detections reported to date, we survey the experimental landscape, presenting the parameters and capabilities of relevant instruments such as COMAP, mmIMe, AIM-CO, CCAT-p, TIME, CONCERTO, CHIME, HIRAX, HERA, STARFIRE, MeerKAT/SKA and SPHEREx. Finally, we describe recent theoretical advances: different approaches to modeling line luminosity functions, several techniques to separate the desired signal from foregrounds, statistical methods to analyze the data, and frameworks to generate realistic intensity map simulations., Comment: 99 pages, 48 figures; Endorsement and any comments welcome; To be submitted to Physics Reports

Millimeter-wave continuum astronomy is today an indispensable tool for both general Astrophysics studies and Cosmology. General purpose, large field-of-view instruments are needed to map the sky at intermediate angular scales not accessible by the high-resolution interferometers and by the coarse angular resolution space-borne or ground-based surveys. These instruments have to be installed at the focal plane of the largest single-dish telescopes. In this context, we have constructed and deployed a multi-thousands pixels dual-band (150 and 260 GHz, respectively 2mm and 1.15mm wavelengths) camera to image an instantaneous field-of-view of 6.5arc-min and configurable to map the linear polarization at 260GHz. We are providing a detailed description of this instrument, named NIKA2 (New IRAM KID Arrays 2), in particular focusing on the cryogenics, the optics, the focal plane arrays based on Kinetic Inductance Detectors (KID) and the readout electronics. We are presenting the performance measured on the sky during the commissioning runs that took place between October 2015 and April 2017 at the 30-meter IRAM (Institut of Millimetric Radio Astronomy) telescope at Pico Veleta. NIKA2 has been successfully deployed and commissioned, performing in-line with the ambitious expectations. In particular, NIKA2 exhibits FWHM angular resolutions of around 11 and 17.5 arc-seconds at respectively 260 and 150GHz. The NEFD (Noise Equivalent Flux Densities) demonstrated on the maps are, at these two respective frequencies, 33 and 8 mJy*sqrt(s). A first successful science verification run has been achieved in April 2017. The instrument is currently offered to the astronomical community during the coming winter and will remain available for at least the next ten years., Comment: Accepted for publication on Astronomy & Astrophysics, in press

Follow-up observations at high-angular resolution of submillimeter galaxies showed that the single-dish sources are comprised of a blend of several galaxies. Consequently, number counts derived from low and high angular resolution observations are in disagreement. This demonstrates the importance of resolution effects and the need to have realistic simulations to explore them. We built a new 2deg^2 simulation of the extragalactic sky from the far-infrared to the submillimeter. It is based on an updated version of the two star-formation mode galaxy evolution model. Using global galaxy properties, we use the abundance matching technique to populate a dark-matter lightcone and thus simulate the clustering. We produce maps and extract the sources, and show that the limited angular resolution of single-dish instruments have a strong impact on (sub)millimeter continuum observations. Taking into account these resolution effects, we are reproducing a large set of observables, including number counts, redshift distributions, and cosmic infrared background power spectra. Our simulation describes consistently the number counts from single-dish telescopes and interferometers. In particular, at 350 and 500 um, we find that number counts measured by Herschel between 5 and 50 mJy are biased towards high values by a factor 2, and that redshift distributions are biased towards low z. We also show that the clustering has an important impact on the Herschel pixel histogram used to derive number counts from P(D) analysis. Finally, we demonstrate that the large number density of red Herschel sources found in observations but not in models could be an observational artifact caused by the combination of noise, resolution effects, and the steepness of color and flux density distributions. Our simulation (SIDES) is available at http://cesam.lam.fr/sides, Comment: 22 pages, 17 figures, version accepted by A&A (red source section significantly improved following the comments of the referee), simulated catalog available at http://cesam.lam.fr/sides

The characterization of the Galactic foregrounds has been shown to be the main obstacle in thechallenging quest to detect primordial B-modes in the polarized microwave sky. We make use of the Planck-HFI 2015 data release at high frequencies to place new constraints on the properties of the polarized thermal dust emission at high Galactic latitudes. Here, we specifically study the spatial variability of the dust polarized spectral energy distribution (SED), and its potential impact on the determination of the tensor-to-scalar ratio, r. We use the correlation ratio of the angular power spectra between the 217 and 353 GHz channels as a tracer of these potential variations, computed on different high Galactic latitude regions, ranging from 80% to 20% of the sky. The new insight from Planck data is a departure of the correlation ratio from unity that cannot be attributed to a spurious decorrelation due to the cosmic microwave background, instrumental noise, or instrumental systematics. The effect is marginally detected on each region, but the statistical combination of all the regions gives more than 99% confidence for this variation in polarized dust properties. In addition, we show that the decorrelation increases when there is a decrease in the mean column density of the region of the sky being considered, and we propose a simple power-law empirical model for this dependence, which matches what is seen in the Planck data. We explore the effect that this measured decorrelation has on simulations of the BICEP2-Keck Array/Planck analysis and show that the 2015 constraints from these data still allow a decorrelation between the dust at 150 and 353 GHz that is compatible with our measured value. Finally, using simplified models, we show that either spatial variation of the dust SED or of the dust polarization angle are able to produce decorrelations between 217 and 353 GHz data similar to the values we observe in the data.

We present new measurements of the power spectra of the cosmic infrared background (CIB) anisotropies using the Planck 2015 full-mission HFI data at 353, 545, and 857 GHz over 20000 square degrees. We use techniques similar to those applied for the cosmological analysis of Planck, subtracting dust emission at the power spectrum level. Our analysis gives stable solutions for the CIB power spectra with increasing sky coverage up to about 50% of the sky. These spectra agree well with Hi cleaned spectra from Planck measured on much smaller areas of sky with low Galactic dust emission. At 545 and 857 GHz our CIB spectra agree well with those measured from Herschel data. We find that the CIB spectra at l > 500 are well fitted by a power-law model for the clustered CIB, with a shallow index {\gamma}^cib = 0.53\pm0.02. This is consistent with the CIB results at 217 GHz from the cosmological parameter analysis of Planck. We show that a linear combination of the 545 and 857 GHz Planck maps is dominated by CIB fluctuations at multipoles l > 300., Comment: 38 pages, 25 figures, submitted to MNRAS

We explore the detection, with upcoming spectroscopic surveys, of three-dimensional power spectra of emission line fluctuations produced in different phases of the Interstellar Medium (ISM) by ionized carbon, ionized nitrogen and neutral oxygen at redshift z>4. The emission line [CII] from ionized carbon at 157.7 micron, and multiple emission lines from carbon monoxide, are the main targets of planned ground-based surveys, and an important foreground for future space-based surveys like the Primordial Inflation Explorer (PIXIE). However, the oxygen [OI] (145.5 micron) line, and the nitrogen [NII] (121.9 micron and 205.2 micron) lines, might be detected in correlation with [CII] with reasonable signal-to-noise ratio (SNR). These lines are important coolants of both the neutral and the ionized medium, and probe multiple phases of the ISM. We compute predictions of the three-dimensional power spectra for two surveys designed to target the [CII] line, showing that they have the required sensitivity to detect cross-power spectra with the [OI] line, and the [NII] lines with sufficient SNR. The importance of cross-correlating multiple lines is twofold. On the one hand, we will have multiple probes of the different phases of the ISM, which is key to understand the interplay between energetic sources, the gas and dust at high redshift. This kind of studies will be useful for a next-generation space observatory such as the NASA Far-IR Surveyor. On the other end, emission lines from external galaxies are an important foreground when measuring spectral distortions of the Cosmic Microwave Background spectrum with future space-based experiments like PIXIE; measuring fluctuations in the intensity mapping regime will help constraining the mean amplitude of these lines, and will allow us to better handle this important foreground., Comment: 13 pages, 2 table, 7 figures, Accepted for publication in ApJ

We present new measurements of the power spectra of the cosmic infrared background (CIB) anisotropies using the Planck 2015 full-mission HFI data at 353, 545, and 857 GHz over 20000 square degrees. We use techniques similar to those applied for the cosmological analysis of Planck, subtracting dust emission at the power spectrum level. Our analysis gives stable solutions for the CIB power spectra with increasing sky coverage up to about 50% of the sky. These spectra agree well with Hi cleaned spectra from Planck measured on much smaller areas of sky with low Galactic dust emission. At 545 and 857 GHz our CIB spectra agree well with those measured from Herschel data. We find that the CIB spectra at l > 500 are well fitted by a power-law model for the clustered CIB, with a shallow index {\gamma}^cib = 0.53\pm0.02. This is consistent with the CIB results at 217 GHz from the cosmological parameter analysis of Planck. We show that a linear combination of the 545 and 857 GHz Planck maps is dominated by CIB fluctuations at multipoles l > 300., Comment: 38 pages, 25 figures, submitted to MNRAS

We explore the detection, with upcoming spectroscopic surveys, of three-dimensional power spectra of emission line fluctuations produced in different phases of the Interstellar Medium (ISM) by ionized carbon, ionized nitrogen and neutral oxygen at redshift z>4. The emission line [CII] from ionized carbon at 157.7 micron, and multiple emission lines from carbon monoxide, are the main targets of planned ground-based surveys, and an important foreground for future space-based surveys like the Primordial Inflation Explorer (PIXIE). However, the oxygen [OI] (145.5 micron) line, and the nitrogen [NII] (121.9 micron and 205.2 micron) lines, might be detected in correlation with [CII] with reasonable signal-to-noise ratio (SNR). These lines are important coolants of both the neutral and the ionized medium, and probe multiple phases of the ISM. We compute predictions of the three-dimensional power spectra for two surveys designed to target the [CII] line, showing that they have the required sensitivity to detect cross-power spectra with the [OI] line, and the [NII] lines with sufficient SNR. The importance of cross-correlating multiple lines is twofold. On the one hand, we will have multiple probes of the different phases of the ISM, which is key to understand the interplay between energetic sources, the gas and dust at high redshift. This kind of studies will be useful for a next-generation space observatory such as the NASA Far-IR Surveyor. On the other end, emission lines from external galaxies are an important foreground when measuring spectral distortions of the Cosmic Microwave Background spectrum with future space-based experiments like PIXIE; measuring fluctuations in the intensity mapping regime will help constraining the mean amplitude of these lines, and will allow us to better handle this important foreground., Comment: 13 pages, 2 table, 7 figures, Accepted for publication in ApJ

Given the current and past star-formation in the Milky Way in combination with the limited gas supply, the re-fuelling of the reservoir of cool gas is an important aspect of Galactic astrophysics. The infall of \ion{H}{i} halo clouds can, among other mechanisms, contribute to solving this problem. We study the intermediate-velocity cloud IVC135+54 and its spatially associated high-velocity counterpart to look for signs of a past or ongoing interaction. Using the Effelsberg-Bonn \ion{H}{i} Survey data, we investigated the interplay of gas at different velocities. In combination with far-infrared Planck and IRIS data, we extended this study to interstellar dust and used the correlation of the data sets to infer information on the dark gas. The velocity structure indicates a strong compression and deceleration of the infalling high-velocity cloud (HVC), associated with far-infrared excess emission in the intermediate-velocity cloud. This excess emission traces molecular hydrogen, confirming that IVC135+54 is one of the very few molecular halo clouds. The high dust emissivity of IVC135+54 with respect to the local gas implies that it consists of disk material and does not, unlike the HVC, have an extragalactic origin. Based on the velocity structure of the HVC and the dust content of the IVC, a physical connection between them appears to be the logical conclusion. Since this is not compatible with the distance difference between the two objects, we conclude that this particular HVC might be much closer to us than complex C. Alternatively, the indicators for an interaction are misleading and have another origin., Comment: 11 pages, 10 figures, accepted for publication in A&A

Semi-analytical models (SAMs) are currently the best way to understand the formation of galaxies within the cosmic dark-matter structures. While they fairly well reproduce the local stellar mass functions, correlation functions and luminosity functions, they fail to match observations at high redshift (z > 3) in most cases, particularly in the low-mass range. The inconsistency between models and observations indicates that the history of gas accretion in galaxies, within their host dark-matter halo, and the transformation of gas into stars, are not well followed. Hereafter, we briefly present a new version of the GalICS semi-analytical model. We explore the impacts of classical mechanisms, such as supernova feedback or photoionization, on the evolution of the stellar mass assembly. Even with a strong efficiency, these two processes cannot explain the observed stellar mass function and star formation rate distribution and some other relations. We thus introduce an ad-hoc modification of the standard paradigm, based on the presence of a \textit{no-star-forming} gas component, and a concentration of the star-forming gas in galaxy discs. The main idea behind the existence of the no-star-forming gas reservoir is that only a fraction of the total gas mass in a galaxy is available to form stars. The reservoir generates a delay between the accretion of the gas and the star formation process. This new model is in much better agreement with the observations of the stellar mass function in the low-mass range than the previous models, and agrees quite well with a large set of observations, including the redshift evolution of the specific star formation rate. However, it predicts a large fraction of no-star-forming baryonic gas, potentially larger than observed, even if its nature has still to be examined in the context of the missing baryon problem.

We present an extended version of the semi-analytical model, GalICS. Like its predecessor, eGalICS applies a post-treatment of the baryonic physics on pre-computed dark-matter merger trees extracted from an N-body simulation. We review all the mechanisms that affect, at any given time, the formation and evolution of a galaxy in its host dark-matter halo. We mainly focus on the gas cycle from the smooth cosmological accretion to feedback processes. To follow this cycle with high accuracy we introduce some novel prescriptions: i) a smooth baryonic accretion with two phases: a cold mode and a hot mode built on the continuous dark-matter accretion. In parallel to this smooth accretion, we implement the standard photoionisation modelling to reduce the input gas flow on the smallest structures. ii) a complete monitoring of the hot gas phase. We compute the evolution of the core density, the mean temperature and the instantaneous escape fraction of the hot atmosphere by considering that the hot gas is in hydrostatic equilibrium in the dark-matter potential well, and by applying a principle of conservation of energy on the treatment of gas accretion, supernovae and super massive black hole feedback iii) a new treatment for disc instabilities based on the formation, the migration and the disruption of giant clumps. The migration of such clumps in gas-rich galaxies allows to form pseudo-bulges. The different processes in the gas cycle act on different time scales, and we thus build an adaptive time-step scheme to solve the evolution equations. The model presented here is compared in detail to the observations of stellar-mass functions, star formation rates, and luminosity functions, in a companion paper.

We measure the cross-power spectra between luminous red galaxies (LRGs) from the Sloan Digital Sky Survey (SDSS)-III Data Release Eight (DR8) and cosmic infrared background (CIB) anisotropies from Planck and data from the Improved Reprocessing (IRIS) of the Infrared Astronomical Satellite (IRAS) at 353, 545, 857, and 3000 GHz, corresponding to 850, 550, 350 and 100 micron, respectively, in the multipole range 100