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J. L. Puget

Publications and source records attributed to J. L. Puget.

At least 19 recordsLinked to original sources
arXiv2023

Polarization angle accuracy for future CMB experiments. The COSMOCal project and its prototype in the 1mm band

The Cosmic Microwave Background (CMB) radiation offers a unique window into the early Universe, facilitating precise examinations of fundamental cosmological theories. However, the quest for detecting B-modes in the CMB, predicted by theoretical models of inflation, faces substantial challenges in terms of calibration and foreground modeling. The COSMOCal (COsmic Survey of Millimeter wavelengths Objects for CMB experiments Calibration) project aims at enhancing the accuracy of the absolute calibration of the polarization angle $ψ$ of current and future CMB experiments. The concept includes the build of a very well known artificial source emitting in the frequency range [20-350] GHz that would act as an absolute calibrator for several polarization facilities on Earth. A feasibility study to place the artificial source in geostationary orbit, in the far field for all the telescopes on Earth, is ongoing. In the meanwhile ongoing hardware work is dedicated to build a prototype to test the technology, the precision and the stability of the polarization recovering in the 1 mm band (220-300 GHz). High-resolution experiments as the NIKA2 camera at the IRAM 30m telescope will be deployed for such use. Once carefully calibrated ($Δψ$ < 0.1 degrees) it will be used to observe astrophysical sources such as the Crab nebula, which is the best candidate in the sky for the absolute calibration of CMB experiments.

astro-ph.IM↗
arXiv2015

Probing star formation in the dense environments of z~1 lensing halos aligned with dusty star-forming galaxies detected with the South Pole Telescope

We probe star formation in the environments of massive $\sim10^{13}\,M_{\odot}$ dark matter halos at redshifts of $z$$\sim$$1$. This star formation is linked to a sub-millimetre clustering signal which we detect in maps of the Planck High Frequency Instrument that are stacked at the positions of a sample of high-redshift ($z$$>$$2$) strongly-lensed dusty star-forming galaxies (DSFGs) selected from the South Pole Telescope (SPT) 2500 deg$^2$ survey. The clustering signal has sub-millimetre colours which are consistent with the mean redshift of the foreground lensing halos ($z$$\sim$$1$). We report a mean excess of star formation rate (SFR) compared to the field, of $(2700\pm700)\,M_{\odot}\,{yr}^{-1}$ from all galaxies contributing to this clustering signal within a radius of 3.5' 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$\%$ of the excess emission measured by Planck originates from galaxies lying in the neighbouring halos 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\pm40)$$\,M_{\odot}\,{yr}^{-1}$ per resolved, clustered source. Our findings suggest that the environments around these massive $z$$\sim$$1$ lensing halos 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.

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arXiv2010

Measurement of the Crab nebula polarization at 90 GHz as a calibrator for CMB experiments

CMB experiments aiming at a precise measurement of the CMB polarization, such as the Planck satellite, need a strong polarized absolute calibrator on the sky to accurately set the detectors polarization angle and the cross-polarization leakage. As the most intense polarized source in the microwave sky at angular scales of few arcminutes, the Crab nebula will be used for this purpose. Our goal was to measure the Crab nebula polarization characteristics at 90 GHz with unprecedented precision. The observations were carried out with the IRAM 30m telescope employing the correlation polarimeter XPOL and using two orthogonally polarized receivers. We processed the Stokes I, Q, and U maps from our observations in order to compute the polarization angle and linear polarization fraction. The first is almost constant in the region of maximum emission in polarization with a mean value of alpha_Sky=152.1+/-0.3 deg in equatorial coordinates, and the second is found to reach a maximum of Pi=30% for the most polarized pixels. We find that a CMB experiment having a 5 arcmin circular beam will see a mean polarization angle of alpha_Sky=149.9+/-0.2 deg and a mean polarization fraction of Pi=8.8+/-0.2%.

astro-ph.CO↗
arXiv2006

Archeops In-flight Performance, Data Processing and Map Making

Archeops is a balloon--borne experiment widely inspired by the Planck satellite and by its High Frequency Instrument (HFI). It is mainly dedicated to measure the Cosmic Microwave Background (CMB) temperature anisotropies at high angular resolution (about 12 arcminutes) over a large fraction of the sky (around 30 %) in the millimetre and submillimetre range at 143, 217, 353 and 545 GHz. Further, the Archeops 353 GHz channel consists of three pairs of polarized sensitive bolometers designed to detect the polarized diffuse emission of Galactic dust. We present in this paper the update of the instrumental setup as well as the inflight performance for the last Archeops flight campaign in February 2002 from Kiruna (Sweden). We also describe the processing and analysis of the Archeops time ordered data for that campaign which lead to the measurement of the CMB anisotropies power spectrum in the multipole range l=10-700 (Benoit et al. 2003a, Tristram et al. 2005) and to the first measurement of the dust polarized emission at large angular scales and its polarized. We present maps of 30 % of the sky of the Galactic emission, including the Galactic plane, in the four Archeops channels at 143, 217, 353 and 545 GHz and maps of the CMB anisotropies at 143 and 217 GHz. These are the firstever available sub--degree resolution maps in the millimetre and submillimetre range of the large angular-scales Galactic dust diffuse emission and CMB temperature anisotropies respectively.

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arXiv2004

ISOCAM observations of the L1551 star formation region

The results of a deep mid-IR ISOCAM survey of the L1551 dark molecular cloud are presented. The aim of this survey is a search for new YSO (Young Stellar Object) candidates, using two broad-band filters centred at 6.7 and 14.3 micron. Although two regions close to the centre of L1551 had to be avoided due to saturation problems, 96 sources were detected in total (76 sources at 6.7 micron and 44 sources at 14.3 micron). Using the 24 sources detected in both filters, 14 were found to have intrinsic mid-IR excess at 14.3 micron and were therefore classified as YSO candidates. Using additional observations in B, V, I, J, H and K obtained from the ground, most candidates detected at these wavelengths were confirmed to have mid-IR excess at 6.7 micron as well, and three additional YSO candidates were found. Prior to this survey only three YSOs were known in the observed region (avoiding L1551 IRS5/NE and HL/XZ Tau). This survey reveals 15 new YSO candidates, although several of these are uncertain due to their extended nature either in the mid-IR or in the optical/near-IR observations. Two of the sources with mid-IR excess are previously known YSOs, one is a brown dwarf MHO 5 and the other is the well known T Tauri star HH30, consisting of an outflow and an optically thick disk seen edge on.

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arXiv2004

The young stellar population in the Serpens Cloud Core: An ISOCAM survey

We present results from an ISOCAM survey in the two broad band filters LW2 (5-8.5 mu) and LW3 (12-18 mu) of a 0.13 square degree coverage of the Serpens Main Cloud Core. A total of 392 sources were detected in the 6.7 mu band and 139 in the 14.3 mu band to a limiting sensitivity of ~ 2 mJy. Only about 50% of the mid-IR excess sources show excesses in the near-IR J-H/H-K diagram. In the central Cloud Core the Class I/Class II number ratio is 19/18, i.e. about 10 times larger than in other young embedded clusters such as rho Ophiuchi or Chamaeleon. The mid-IR fluxes of the Class I and flat-spectrum sources are found to be on the average larger than those of Class II sources. Stellar luminosities are estimated for the Class II sample, and its luminosity function is compatible with a coeval population of about 2 Myr which follows a three segment power-law IMF. For this age about 20% of the Class IIs are found to be young brown dwarf candidates. The YSOs are in general strongly clustered, the Class I sources more than the Class II sources, and there is an indication of sub-clustering. The sub-clustering of the protostar candidates has a spatial scale of 0.12 pc. These sub-clusters are found along the NW-SE oriented ridge and in very good agreement with the location of dense cores traced by millimeter data. The smallest clustering scale for the Class II sources is about 0.25 pc, similar to what was found for rho Ophiuchi. Our data show evidence that star formation in Serpens has proceeded in several phases, and that a ``microburst'' of star formation has taken place very recently, probably within the last 10^5 yrs.

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arXiv2003

The Planck High Frequency Instrument, a 3rd generation CMB experiment, and a full sky submillimeter survey

The High Frequency Instrument (HFI) of Planck is the most sensitive CMB experiment ever planned. Statistical fluctuations (photon noise) of the CMB itself will be the major limitation to the sensitivity of the CMB channels. Higher frequency channels will measure galactic foregrounds. Together with the Low Frequency Instrument, this will make a unique tool to measure the full sky and to separate the various components of its spectrum. Measurement of the polarization of these various components will give a new picture of the CMB. In addition, HFI will provide the scientific community with new full sky maps of intensity and polarization at six frequencies, with unprecedented angular resolution and sensitivity. This paper describes the logics that prevailed to define the HFI and the performances expected from this instrument. It details several features of the HFI design that have not been published up to now.

astro-ph↗
arXiv2001

Cosmic Background dipole measurements with Planck-High Frequency Instrument

This paper discusses the Cosmic Background (CB) dipoles observations in the framework of the Planck mission. Dipoles observations can be used in three ways: (i) It gives a measurement of the peculiar velocity of our Galaxy which is an important observation in large scale structures formation model. (ii) Measuring the dipole can give unprecedent information on the monopole (that can be in some cases hard to obtain due to large foreground contaminations). (iii) The dipole can be an ideal absolute calibrator, easily detectable in cosmological experiments. Following the last two objectives, the main goal of the work presented here is twofold. First, we study the accuracy of the Planck-HFI calibration using the Cosmic Microwave Background (CMB) dipole measured by COBE as well as the Earth orbital motion dipole. We show that we can reach for HFI, a relative calibration between rings of about 1% and an absolute calibration better than 0.4% for the CMB channels (in the end, the absolute calibration will be limited by the uncertainties on the CMB temperature). We also show that Planck will be able to measure the CMB dipole direction at better than 1.7 arcmin and improve on the amplitude. Second, we investigate the detection of the Cosmic Far-Infrared Background (FIRB) dipole. Measuring this dipole could give a new and independent determination of the FIRB for which a direct determination is quite difficult due to Galactic dust emission contamination. We show that such a detection would require a Galactic dust emission removal at better than 1%, which will be very hard to achieve.

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arXiv2001

ISOCAM observations of the rho Ophiuchi cloud: Luminosity and mass functions of the pre-main sequence embedded cluster

We present the results of the first extensive mid-infrared (IR) imaging survey of the rho Ophiuchi embedded cluster, performed with the ISOCAM camera on board the ISO satellite. The main molecular cloud L1688, as well as L1689N and L1689S, have been completely surveyed for point sources at 6.7 and 14.3 micron. A total of 425 sources are detected including 16 Class I, 123 Class II, and 77 Class III young stellar objects (YSOs). Essentially all of the mid-IR sources coincide with near-IR sources, but a large proportion of them are recognized for the first time as YSOs. Our dual-wavelength survey allows us to identify essentially all the YSOs with IR excess in the embedded cluster down to Fnu ~ 10 - 15 mJy. It more than doubles the known population of Class II YSOs and represents the most complete census to date of newly formed stars in the rho Ophiuchi central region. The stellar luminosity function of the complete sample of Class II YSOs is derived with a good accuracy down to L= 0.03 Lsun. A modeling of this lumino- sity function, using available pre-main sequence tracks and plausible star for- mation histories, allows us to derive the mass distribution of the Class II YSOs which arguably reflects the IMF of the embedded cluster. We estimate that the IMF in rho Ophiuchi is well described by a two-component power law with a low- mass index of -0.35+/-0.25, a high-mass index of -1.7 (to be compared with the Salpeter value of -1.35), and a break occurring at M = 0.55+/-0.25 Msun. This IMF is flat with no evidence for a low-mass cutoff down to at least 0.06 Msun.

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arXiv2000

Implications of the cosmic infrared background for light production and the star formation history in the Universe

The Cosmic Background due to the integrated radiation from galaxies over the whole life of the Universe is reviewed. We find that this background is well constrained by measurements. The total power in the background is in the range 60-93 nW/m2/sr. The data show the existence of a minimum separating the direct stellar radiation from the infrared part due to radiation reemitted by dust. This reemitted dust radiation is about 1-2.6 time the background power in the optical/near-IR thus much larger than the same ratio measured locally (30%). The far-infrared and submillimeter background is likely to be dominated by redshifted infrared galaxies. The long wavelength spectrum of the background being significantly flatter than the spectrum of these galaxies it strongly constrains the far-infrared radiation production rate history which must increase by a factor larger than 10 between the present time and a redshift 1 and then stays rather constant at higher redshift, contrary to the ultraviolet radiation production rate which decreases rapidly. Several models of galaxy evolution have been proposed to explain the submillimeter background. In this paper we do not propose a new model; we systematically explore the allowed range of evolution histories allowed by the data. If infrared galaxies are mostly powered by starbursts as indicated by recent observations, this infrared production history reflects the history of starbursts in the Universe.

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arXiv1999

Source Counts from the 15 microns ISOCAM Deep Surveys

We present the results of the five mid-IR 15 microns (12-18 microns LW3 band) ISOCAM Guaranteed Time Extragalactic Surveys performed in the regions of the Lockman Hole and Marano Field. The roughly 1000 sources detected, 600 of which have a flux above the 80 % completeness limit, guarantee a very high statistical significance for the integral and differential source counts from 0.1 mJy up to 5 mJy. By adding the ISOCAM surveys of the HDF-North and South (plus flanking fields) and the lensing cluster A2390 at low fluxes and IRAS at high fluxes, we cover four decades in flux from 50 microJy to 0.3 Jy. The slope of the differential counts is very steep (alpha =-3.0) in the flux range 0.4-4 mJy, hence much above the Euclidean expectation of alpha =-2.5. When compared with no-evolution models based on IRAS, our counts show a factor of 10 excess at 400 microJy, and a fast convergence, with alpha =-1.6 at lower fluxes.

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arXiv1999

Detection of the extra-Galactic background fluctuations at 170 $μ$m

We have used the Marano1 field observations with ISOPHOT at 170 $μ$m to search for the Cosmic Far-InfraRed Background fluctuations. This field is part of the FIRBACK project (Puget et al., 1999a). For the first time, fluctuations due to unresolved extra-Galactic sources are isolated. The emission of such sources clearly dominates, at arcminute scales, the background fluctuations in the lowest Galactic emission regions. The study presented here is based on a power spectrum analysis which allow to statistically separate each of the background components. With this analysis, we clearly show that we detect the CFIRB fluctuations.

astro-ph↗
arXiv1999

Isocam Extragalactic Mid-Infrared Deep Surveys Unveiling Dust-Enshrouded Star Formation In The Universe

ISOCAM extragalactic mid-infrared deep surveys have detected a population of strong IR emitters ten times more numerous than expected if there were no evolution from z<0.2 (IRAS) up to the maximum redshift of these galaxies (z=1.5). The mid-IR cosmic background produced by these galaxies (2.35+/-0.8 nW m^-2 sr^-1, at 15 microns above 50 microJy) is larger than 30 per cent of the energy radiated in the I band by the optical galaxies detected in the HDF, which are two orders of magnitude more numerous. This fraction is much higher than in the local universe (z<0.2) as probed by IRAS, where all integrated IR emission from 8 to 1000 microns makes 30 per cent of the optical starlight. Even assuming a conservative SED, they produce a major contribution to the 140 mu m DIRBE background measured by Hauser et al. (1998, 25.1+/-7 nW m^-2 sr^-1) and Lagache et al. (1999, 15.3+/-9.5 nW m^ -2 sr^-1). This is both a confirmation of the strong IR cosmic background that was first detected by Puget et al. (1996) and the first identification of the galaxies responsible for a large fraction of this background at 140 microns. We find that these bright (several 10^11 Lsol) and massive ( = 1.5x10^11 Msol) IR galaxies have a typical redshift of z=0.7 and optical colors similar to field galaxies. The fraction of galaxies with morphological signs of interactions is larger at higher redshift. This is consistent with the nature of local luminous IR galaxies found by IRAS, which often exhibit evidence of galaxy interaction or merging and indicates that interactions should play a crucial role in the evolution of galaxies as expected from bottom-up scenarios.

astro-ph↗
arXiv1999

The FIR/submm window on galaxy formation

Our view on the deep universe has been so far biased towards optically bright galaxies. Now, the measurement of the Cosmic Infrared Background in FIRAS and DIRBE residuals, and the observations of FIR/submm sources by the ISOPHOT and SCUBA instruments begin unveiling the ``optically dark side'' of galaxy formation. Though the origin of dust heating is still unsolved, it appears very likely that a large fraction of the FIR/submm emission is due to heavily-extinguished star formation. Consequently, the level of the CIRB implies that about 2/3 of galaxy/star formation in the universe is hidden by dust shrouds. In this review, we introduce a new modeling of galaxy formation and evolution that provides us with specific predictions in FIR/submm wavebands. These predictions are compared with the current status of the observations. Finally, the capabilities of current and forthcoming instruments for all-sky and deep surveys of FIR/submm sources are briefly described.

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arXiv1998

The interstellar cold dust observed by COBE

Using DIRBE and FIRAS maps at high latitude ($|b|>10^{\circ}$) we derive the spatial distribution of the dust temperature associated with the diffuse cirrus and the dense molecular clouds. For a $ν^2$ emissivity law, we find that the equilibrium dust temperature of the cirrus is about 17.5 K with only small variations over the high latitude sky. Comparison of the far Infrared DIRBE maps shows the presence of a colder emission component with a temperature around 15 K, assuming a $ν^2$ emissivity law. The lowest values of the temperature found in the cold regions ($\sim 13 K$) are compatible with the results recently obtained for dense cores in star forming regions by the balloon-borne experiment SPM-PRONAOS (Ristorcelli et al., 1996, 1998, Serra et al., 1997). This cold component is in particular present in the direction of known molecular complexes with low star forming activity such as Taurus. The association between the cold component and molecular clouds is further demonstrated by the fact that all sky pixels with significant cold emission have an excess IR emission with respect to the high latitude IR/HI correlation. We have deduced a threshold value of the column density, $N_{HI} = 2.5 10^{20} H/cm^2$, below which cold dust is not detected within the FIRAS beam of $\sim 7\degr$. We have re-examined the problem of the existence of a very cold dust component ($T \sim 7 K$) by combining DIRBE maps of the cold emission with FIRAS spectra, corrected for the isotropic component found in Puget et al. (1996). The warm and cold component deduced from the analysis of DIRBE maps account for the Galactic FIRAS spectra with no need for a very cold component ($T\sim7$ K).

astro-ph↗
arXiv1998

FIRBACK: I. A deep survey at 175 $μ$m with ISO, preliminary results

FIRBACK is a deep survey conducted with the ISOPHOT instrument aboard the Infrared Space Observatory (ISO) at an effective wavelength of 175 $μ$m. We present here results we have obtained on the first field, the so-called Marano1 which covers around 0.25 square degree. We find that the source density for objects with a flux above 200 mJy exceeds the counts expected for sources found in the IRAS deep surveys with a similar flux by about an order of magnitude. Such an excess was expected on the basis of the high far infrared background detected with the FIRAS and DIRBE instruments aboard the Cosmic Background Explorer (COBE). These sources are likely to be redshifted infrared galaxies. The steep number counts indicate strong cosmological evolution in this population. The detected sources account for only 10 % of the cosmic IR background. An extrapolation of the counts down to about 10 mJy would be needeed to account for the whole background at this wavelength.

astro-ph↗
arXiv1998

Isocam deep surveys unveiling star formation in the mid-infrared

Before having exhausted the helium in its tank on April 8, 1998, the Infrared Space Observatory had time to perform several complementary surveys at various depths and areas within selected regions of the sky. We present the results of some of the surveys done with the mid-infrared camera, ISOCAM, on-board ISO, and more specifically those surveys which were performed using the broad-band filter LW3 (12-18 microns). We show that mid-infrared allows to discriminate starburst and post-starburst galaxies among galaxies which present similar optical-UV morphological and colour signatures. Furthermore, the strong evolution found in the surveys indicates that more star formation is hidden in the infrared at higher redshifts.

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