arXiv subjects

A. Bideaud

Publications and source records attributed to A. Bideaud.

At least 19 recordsLinked to original sources

arXiv2024

KISS: instrument description and performance

Kinetic inductance detectors (KIDs) have been proven as reliable systems for astrophysical observations, especially in the millimetre range. Their compact size enables to optimally fill the focal plane, thus boosting sensitivity. The KISS (KIDs Interferometric Spectral Surveyor) instrument is a millimetre camera that consists of two KID arrays of 316 pixels each coupled to a Martin-Puplett interferometer (MPI). The addition of the MPI grants the KIDs camera the ability to provide spectral information in the 100 and 300 GHz range. In this paper we report the main properties of the KISS instrument and its observations. We also describe the calibration and data analysis procedures used. We present a complete model of the observed data including the sky signal and several identified systematics. We have developed a full photometric and spectroscopic data analysis pipeline that translates our observations into science-ready products. We show examples of the results of this pipeline on selected sources: Moon, Jupiter and Venus. We note the presence of a deficit of response with respect to expectations and laboratory measurements. The detectors noise level is consistent with values obtained during laboratory measurements, pointing to a sub-optimal coupling between the instrument and the telescope as the most probable origin for the problem. This deficit is large enough as to prevent the detection of galaxy clusters, which were KISS main scientific objective. Nevertheless, we have demonstrated the feasibility of this kind of instrument, in the prospect for other KID interferometers (such as the CONCERTO instrument). As this regard, we have developed key instrumental technologies such as optical conception, readout electronics and raw calibration procedures, as well as, adapted data analysis procedures.

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arXiv2021

Observations with KIDs Interferometer Spectrum Survey(KISS)

We describe the preliminary on-sky results of the KIDs Interferometer Spectrum Survey (KISS), a spectral imager with a 1 deg field of view (FoV). The instrument operates in the range 120-180 GHz from the 2.25 m Q-U-I JOint TEnerife telescope in Teide Observatory (Tenerife, Canary Islands), at 2 395 m altitude above sea level. Spectra at low resolution, up to 1.45 GHz, are obtained using a fast (3.72 Hz mechanical frequency) Fourier transform spectrometer, coupled to a continuous dilution cryostat with a stabilized temperature of 170 mK that hosts two 316-pixel arrays of lumped-element kinetic inductance detectors. KISS generates more than 3 000 spectra per second during observations and represents a pathfinder to demonstrate the potential for spectral mapping with large FoV. We give an overall description of the spectral mapping paradigm and we present recent results from observations, in this paper.

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arXiv2021

Accurate sky signal reconstruction for ground-based spectroscopy with kinetic inductance detectors

Context. Wide-field spectrometers are needed to deal with current astrophysical challenges that require multiband observations at millimeter wavelengths. An example of these is the KIDs Interferometer Spectrum Survey (KISS), which uses two arrays of kinetic inductance detectors (KIDs) coupled to a Martin-Puplett interferometer (MPI). KISS has a wide instantaneous field of view (1 deg in diameter) and a spectral resolution up to 1.45 GHz in the 120-180 GHz electromagnetic band. The instrument is installed on the 2.25 m Q-U-I JOint TEnerife telescope in Teide Observatory (Tenerife, Canary Islands), at an altitude of 2395 m above sea level. Aims. This work presents an original readout modulation method developed to improve the sky signal reconstruction accuracy for types of instruments for which a fast sampling frequency is required both to remove atmospheric fluctuations and to perform full spectroscopic measurements on each sampled sky position. Methods. We first demonstrate the feasibility of this technique using simulations. Then, we apply such a scheme to on-sky calibration. Results. We show that the sky signal can be reconstructed to better than 0.5% for astrophysical sources, and to better than 2% for large background variations such as in "skydip", in an ideal noiseless scenario. The readout modulation method is validated by observations on-sky during the KISS commissioning campaign. Conclusions. We conclude that accurate photometry can be obtained for future KID-based MPI.

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arXiv2021

Understanding and minimizing resonance frequency deviations on a 4-inch kilo-pixel kinetic inductance detector array

One of the advantages of kinetic inductance detectors is their intrinsic frequency domain multiplexing capability. However, fabrication imperfections usually give rise to resonance frequency deviations, which create frequency collision and limit the array yield. Here we study the resonance frequency deviation of a 4-inch kilo-pixel lumped-element kinetic inductance detector (LEKID) array using optical mapping. Using the measured resonator dimensions and film thickness, the fractional deviation can be explained within $\pm 25\times 10^{-3}$, whereas the residual deviation is due to variation of electric film properties. Using the capacitor trimming technique, the fractional deviation is decreased by a factor of 14. The yield of the trimming process is found to be 97%. The mapping yield, measured under a 110~K background, is improved from 69% to 76%, which can be further improved to 81% after updating our readout system. With the improvement in yield, the capacitor trimming technique may benefit future large-format LEKID arrays.

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arXiv2020

LEKID sensitivity for space applications between 80 and 600 GHz

We report the design, fabrication and testing of Lumped Element Kinetic Inductance Detectors (LEKID) showing performance in line with the requirements of the next generation space telescopes operating in the spectral range from 80 to 600 GHz. This range is of particular interest for Cosmic Microwave Background (CMB) studies. For this purpose we have designed and fabricated 100-pixel arrays covering five distinct bands. These wafers have been measured via multiplexing, where a full array is read out using a single pair of lines. We adopted a custom cold black-body installed in front of the detectors and regulated at temperatures between 1 K and 20 K. We will describe in the present paper the main design considerations, the fabrication processes, the testing and the data analysis.

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arXiv2020

The XXL Survey XLIV. Sunyaev-Zel'dovich mapping of a low-mass cluster at z~1: a multi-wavelength approach

In this paper, we present resolved observations of the Sunyaev-Zel'dovich (SZ) effect, obtained with the NIKA2 camera, towards the cluster of galaxies XLSSC102, a relatively low-mass system ($M_{500} \sim 2 \times 10^{14}$ M$_{\odot}$) 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 XLSSC102 and stripped the gas out of the galaxy group. The NIKA2 data are also combined with XXL data to construct the thermodynamic profiles of XLSSC102, obtaining relatively tight constraints up to about $\sim r_{500}$, 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 XLSSC102 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$\sim$1, especially with low signal-to-noise ratio (S/N) data and for a disturbed system. However, it also highlights the strength of resolved SZ observations alone and in combination with survey-like X-ray data.

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arXiv2020

KISS: a spectrometric imager for millimetre cosmology

Clusters of galaxies are used to map the large-scale structures in the universe and as probe of universe evolution. They can be observed through the Sunyaev-Zel'dovich (SZ) effect. At this respect the spectro-imaging at low resolution frequency is an important tool, today, for the study of cluster of galaxies. We have developed KISS (KIDs-Interferometer-Spectrum-Survey), a spectrometric imager dedicated to the secondary anisotropies of the Cosmic Microwave Background (CMB). The multi-frequency approach permits to improve the component separation with respect to predecessor experiments. In this paper, firstly, we provide a description of the scientific context and the state of the art of SZ observations. Secondly, we describe the KISS instrument. Finally, we show preliminary results of the ongoing commissioning campaign.

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arXiv2020

Cluster cosmology with the NIKA2 SZ Large Program

The main limiting factor of cosmological analyses based on thermal Sunyaev-Zel'dovich (SZ) cluster statistics comes from the bias and systematic uncertainties that affect the estimates of the mass of galaxy clusters. High-angular resolution SZ observations at high redshift are needed to study a potential redshift or morphology dependence of both the mean pressure profile and of the mass-observable scaling relation used in SZ cosmological analyses. The NIKA2 camera is a new generation continuum instrument installed at the IRAM 30-m telescope. With a large field of view, a high angular resolution and a high-sensitivity, the NIKA2 camera has unique SZ mapping capabilities. In this paper, we present the NIKA2 SZ large program, aiming at observing a large sample of clusters at redshifts between 0.5 and 0.9, and the characterization of the first cluster oberved with NIKA2.

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arXiv2020

Calibration and Performance of the NIKA2 camera at the IRAM 30-meter Telescope

NIKA2 is a dual-band millimetric continuum camera of 2900 Kinetic Inductance Detectors (KID), operating at $150$ and $260\,\rm{GHz}$, installed at the IRAM 30-meter telescope. We present the performance assessment of NIKA2 after one year of observation using a dedicated point-source calibration method, referred to as the \emph{baseline} method. Using a large data set acquired between January 2017 and February 2018 that span the whole range of observing elevations and atmospheric conditions encountered at the IRAM 30-m telescope, we test the stability of the performance parameters. We report an instantaneous field of view (FOV) of 6.5' in diameter, filled with an average fraction of $84\%$ and $90\%$ of valid detectors at $150$ and $260\,\rm{GHz}$, respectively. The beam pattern is characterized by a FWHM of $17.6'' \pm 0.1''$ and $11.1''\pm 0.2''$, and a beam efficiency of $77\% \pm 2\%$ and $55\% \pm 3\%$ at $150$ and $260\,\rm{GHz}$, respectively. The rms calibration uncertainties are about $3\%$ at $150\,\rm{GHz}$ and $6\%$ at $260\,\rm{GHz}$. The absolute calibration uncertainties are of $5\%$ and the systematic calibration uncertainties evaluated at the IRAM 30-m reference Winter observing conditions are below $1\%$ in both channels. The noise equivalent flux density (NEFD) at $150$ and $260\,\rm{GHz}$ are of $9 \pm 1\, \rm{mJy}\cdot s^{1/2}$ and $30 \pm 3\, \rm{mJy}\cdot s^{1/2}$. This state-of-the-art performance confers NIKA2 with mapping speeds of $1388 \pm 174$ and $111 \pm 11 \,\rm{arcmin}^2\cdot \rm{mJy}^{-2}\cdot \rm{h}^{-1}$ at $150$ and $260\,\rm{GHz}$. With these unique capabilities of fast dual-band mapping at high (better that 18'') angular resolution, NIKA2 is providing an unprecedented view of the millimetre Universe.

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arXiv2019

Observing with NIKA2Pol from the IRAM 30m telescope. Early results on the commissioning phase

The NIKA2 polarization channel at 260 GHz (1.15 mm) has been proposed primarily to observe galactic star-forming regions and probe the critical scales between 0.01-0.05 pc at which magnetic field lines may channel the matter of interstellar filaments into growing dense cores. The NIKA2 polarimeter consists of a room temperature continuously rotating multi-mesh HWP and a cold polarizer that separates the two orthogonal polarizations onto two 260 GHz KIDs arrays. We describe in this paper the preliminary results obtained during the most recent commissioning campaign performed in December 2018. We concentrate here on the analysis of the extended sources, while the observation of compact sources is presented in a companion paper [12]. We present preliminary NIKA2 polarization maps of the Crab nebula. We find that the integrated polarization intensity flux measured by NIKA2 is consistent with expectations.In terms of polarization angle, we are still limited by systematic uncertainties that will be further investigated in the forthcoming commissioning campaigns.

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arXiv2019

The KISS experiment

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 characterizing the clusters of galaxies via the Sunyaev Zeldovich (SZ) 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 (FoV) 1 degree 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 proceeding we present an overview of the instrument and the latest results.

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arXiv2019

Debris disks around stars in the NIKA2 era

The new NIKA2 camera at the IRAM 30m radiotelescope was used to observe three known debris disks in order to constrain the SED of their dust emission in the millimeter wavelength domain. We have found that the spectral index between the two NIKA2 bands (1mm and 2mm) is consistent with the Rayleigh-Jeans regime (lambda^{-2}), unlike the steeper spectra (lambda^{-3}) measured in the submillimeter-wavelength domain for two of the three disks $-$ around the stars Vega and HD107146. We provide a succesful proof of concept to model this spectral inversion in using two populations of dust grains, those smaller and those larger than a grain radius a0 of 0.5mm. This is obtained in breaking the slope of the size distribution and the functional form of the absorption coefficient of the standard model at a0. The third disk - around the star HR8799 - does not exhibit this spectral inversion but is also the youngest.

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arXiv2019

The NIKA polarimeter on science targets. Crab nebula observations at 150 GHz and dual-band polarization images of Orion Molecular Cloud OMC-1

We present here the polarization system of the NIKA camera and give a summary of the main results obtained and performed studies on Orion and the Crab nebula. The polarization system was equipped with a room temperature continuously rotating multi-mesh half wave plate and a grid polarizer facing the NIKA cryostat window. NIKA even though less sensitive than NIKA2 had polarization capability in both 1 and 2 millimiter bands. NIKA polarization observations demonstrated the ability of such a technology in detecting the polarization of different targets, compact and extended sources like the Crab nebula and Orion Molecular Cloud region OMC-1. These measurements together with the developed techniques to deal with systematics, opened the way to the current observations of NIKA2 in polarization that will provide important advances in the studies of galactic and extra-galactic emission and magnetic fields.

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arXiv2019

NIKA2 mapping and cross-instrument SED extraction of extended sources with Scanamorphos

The steps taken to tailor to NIKA2 observations the Scanamorphos algorithm (initially developed to subtract low-frequency noise from Herschel on-the-fly observations) are described, focussing on the consequences of the different instrument architecture and observation strategy. The method, making the most extensive use of the redundancy built in the multi-scan coverage with large arrays of a given region of the sky, is applicable to extended sources, while the pipeline is so far optimized for compact sources. An example of application is given. A related tool to build consistent broadband SEDs from 60 microns to 2 mm, combining Herschel and NIKA2 data, has also been developed. Its main task is to process the data least affected by low-frequency noise and coverage limitations (i.e. the Herschel data) through the same transfer function as the NIKA2 data, simulating the same scan geometry and applying the same noise and atmospheric signal as extracted from the 1 mm and 2 mm data.

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arXiv2019

A low-mass galaxy cluster as a test-case study for the NIKA2 SZ Large Program

High-resolution mapping of the hot gas in galaxy clusters is a key tool for cluster-based cosmological analyses. Taking advantage of the NIKA2 millimeter camera operated at the IRAM 30-m telescope, the NIKA2 SZ Large Program seeks to get a high-resolution follow-up of 45 galaxy clusters covering a wide mass range at high redshift in order to re-calibrate some of the tools needed for the cosmological exploitation of SZ surveys. We present the second cluster analysis of this program, targeting one of the faintest sources of the sample in order to tackle the difficulties in data reduction for such faint, low-SNR clusters. In this study, the main challenge is the precise estimation of the contamination by sub-millimetric point sources, which greatly affects the tSZ map of the cluster. We account for this contamination by performing a joint fit of the SZ signal and of the flux density of the compact sources. A prior knowledge of these fluxes is given by the adjustment of the SED of each source using data from both NIKA2 and the \textit{Herschel} satellite. The first results are very promising and demonstrate the possibility to estimate thermodynamic properties with NIKA2, even in a compact cluster heavily contaminated by point sources.

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arXiv2019

NIKA: a mm camera for Sunyaev-Zel'dovich science in clusters of galaxies

Clusters of galaxies, the largest bound objects in the Universe, constitute a cosmological probe of choice, which is sensitive to both dark matter and dark energy. Within this framework, the Sunyaev-Zel'dovich (SZ) effect has opened a new window for the detection of clusters of galaxies and for the characterization of their physical properties such as mass, pressure and temperature. NIKA, a KID-based dual band camera installed at the IRAM 30-m telescope, was particularly well adapted in terms of frequency, angular resolution, field-of-view and sensitivity, for the mapping of the thermal and kinetic SZ effect in high-redshift clusters. In this paper, we present the NIKA cluster sample and a review of the main results obtained via the measurement of the SZ effect on those clusters: reconstruction of the cluster radial pressure profile, mass, temperature and velocity.

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arXiv2019

GASTON: Galactic Star Formation with NIKA2: A new population of cold massive sources discovered

Understanding where and when the mass of stars is determined is one of the fundamental, mostly unsolved, questions in astronomy. Here, we present the first results of GASTON, the Galactic Star Formation with NIKA2 large programme on the IRAM 30m telescope, that aims to identify new populations of low-brightness sources to tackle the question of stellar mass determination across all masses. In this paper, we focus on the high-mass star formation part of the project, for which we map a $\sim2$ deg$^2$ region of the Galactic plane around $l=24^\circ$ in both 1.2 mm and 2.0 mm continuum. Half-way through the project, we reach a sensitivity of 3.7 mJy/beam at 1.2mm. Even though larger than our target sensitivity of 2 mJy, the current sensitivity already allows the identification of a new population of cold, compact sources that remained undetected in any (sub-)mm Galactic plane survey so far. In fact, about 25% of the $\sim 1600$ compact sources identified in the 1.2 mm GASTON image are new detections. We present a preliminary analysis of the physical properties of the GASTON sources as a function of their evolutionary stage, arguing for a potential evolution of the mass distribution of these sources with time.

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arXiv2019

Mapping the gas thermodynamic properties of the massive cluster merger MOO J1142$+$1527 at z = 1.2

We present the results of the analysis of the very massive cluster MOO J1142$+$1527 at a redshift $z = 1.2$ based on high angular resolution NIKA2 Sunyaev-Zel'dovich (SZ) and $Chandra$ X-ray data. This multi-wavelength analysis enables us to estimate the shape of the temperature profile with unprecedented precision at this redshift and to obtain a map of the gas entropy distribution averaged along the line of sight. The comparison between the cluster morphological properties observed in the NIKA2 and $Chandra$ maps together with the analysis of the entropy map allows us to conclude that MOO J1142$+$1527 is an on-going merger hosting a cool-core at the position of the X-ray peak. This work demonstrates how the addition of spatially-resolved SZ observations to low signal-to-noise X-ray data can bring valuable insights on the intracluster medium thermodynamic properties at $z>1$.

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