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Introduction: Recent development of anti-βamyloid drugs for dementigenic neurodegenerative diseases treatment necessitates identification of target patients in MCI stage. Clinical framing also relies on the identification of brain hypometabolism patterns suggestive of neurodegeneration detected by PET-FDG. New MRI perfusion methods such pseudo Continuous Arterial Spin Labeling (pCASL) that do not require contrast medium make it possible adding perfusion data to biomarkers useful for diagnosis. A study to define an optimized protocol analysis was conducted, to investigate the correlation between FDG-PET and pCASL information. Material and Methods: FDG-PET, pCASL and structural MR images were acquired from 15 patients (mean age 76 yr.). To validate the present analysis with a standard group analysis, a sample of 111 healthy subjects FDG-PET scans underwent the same processing. Starting from a standard SPM12 pipeline and using customized Matlab routines, an optimized protocol of preprocessing and ROI-based analysis were defined. Results: PET, pCASL and MR were normalized in MNI space and smoothed. A better spatial normalization for pCASL scans was obtained using the source image. Considering PET/pCASL low spatial resolution, different methods of Gray Matter (GM) segmentation were compared. A mean tissue probability map of GM, obtained from 662 healthy elderly subjects in the same patients range of age, was considered and used also for PVE correction in PET scans. For patients, GM obtained using the template was compared with the segmented one from the T1-weighted image to evaluate the eventual atrophy degree or possible cortex reduction due to incomplete atlas-patient cortex superimposition. Standardized Uptake Values (SUVr) from FDG-PET and Cerebral Blood Flow values (CBFr) values form pCASL, both normalized on cerebellar mean values, were calculated for all the 88 cortical regions of the Automated Anatomic Labeling template version 3 (AAL3) and for the 22 macro-regions obtained by combining sub-areas of AAL3. Discussion: According to this optimized protocol, further analysis on images are now being conducted. They will lead to the investigation of correlation between SUVr and CBFr values in the 88 regions and in the 22 macro-regions through Pearson coefficients, histograms and pattern similarities. A validation of the present analysis with the standard spm12 one was also conducted.

Introduction: Multimodal neuroimaging techniques allow to adequately address diagnosis questions issued by clinicians and researchers about human brain behavior. Multimodality means combining different type of information coming from functional and morpho-structural images. This is particularly important in case of neurodegenerative diseases, starting at Mild Cognitive Impairment (MCI) stage, ending to the effective progression to dementia. Brain hypometabolism patterns detected by 18FDG-PET can be combined with hypoperfusion information that nowadays can be non-invasively acquired with new MRI functional sequences, such as pseudo Continuous Arterial Spin Labeling (pCASL). This may allow pCASL to easily become an additional biomarker for diagnosis of dementia. A joint PET-pCASL analysis tool, optimized in preprocessing, was developed and then validated versus the conventional SPM12 toolbox. Material and Methods: An optimized protocol of preprocessing and ROI-based analysis was defined, starting from an SPM12 standard pipeline and using customized Matlab routines. Volumes were all normalized in MNI space. Normalization parameters for pCASL images were defined on the high resolution source image, co-registered to the T1-weigthed image. A mean Gray Matter (GM) tissue probability map, obtained from 662 healthy subjects in the patients range of age, was used for GM segmentation and for PVE correction in 18FDG-PET scans. The developed tool was validated on 20 MCI patients (mean age 76 yr.), assessing outcomes agreement vs a standard SPM12 analysis, using a single subject versus group analysis. This validation was performed on 18FDG-PET data only, where a sample of 111 healthy subjects 18FDG-PET scans was available as control group. In the SPM analysis a general linear model was applied, age was considered as covariate, and significance level was set at 0.05 (FWE-corrected) at a cluster level. Indirect validation for pCASL data, where normative data and a control group were not available, was derived by cross-correlation with 18FDG-PET results. Results: 18FDG-PET Standardized Uptake Values (SUVr) and pCASL Cerebral Blood Flow values (CBFr), both normalized on cerebellar mean values, were calculated in 22 macro-regions obtained by combining sub-areas of the Automated Anatomic Labeling template version 3 (AAL3). For 18FDG-PET, regions that fall outside normality range were the same found to belong to signifi cant clusters in the SPM referenceoutcome. Thereby, a comparison between 18FDG-PET and pCASL relying on SUVr and CBFr values incorresponding regions can be assessed (Fig. 1b). Both regional values and relative ratios between region scan be evaluated. Discussion: The validation of our tool on 18FDG-PET will allow it to be used for further investigation of correlation between SUVr and CBFr values in the 22 macro-regions. References: [1] Y. H. K. Cha, M. A. Jog, Y. C. Kim, S. Chakrapani, S. M. Kraman, and D. J. J. Wang, “Regional correlation between resting state FDG PET and pCASL perfusion MRI,” J. Cereb. Blood Flow Metab., vol. 33, no. 12, pp.1909–1914, Dec. 2013. [2] L. Yan et al., “Regional association of pCASL-MRI with FDG-PET and PiB-PET in people at risk for autosomal dominant Alzheimer’s disease,” NeuroImage. Clin., vol. 17, pp. 751–760, 2017.

Star-forming galaxies are composed of various types of galaxies. However, the luminosity functions at z ≳ 4–5 suggest that most galaxies have a relatively low stellar mass (log Mstar ∼ 10) and a low dust attenuation (AFUV ∼ 1.0). The physical properties of these objects are quite homogeneous. We used an approach where we combined their rest-frame far-infrared and submillimeter emissions and utilized the universe and the redshift as a spectrograph to increase the amount of information in a collective way. From a subsample of 27 ALMA-detected galaxies at z > 4.5, we built an infrared spectral energy distribution composite template. It was used to fit, with CIGALE, the 105 galaxies (detections and upper limits) in the sample from the far-ultraviolet to the far-infrared. The derived physical parameters provide information to decipher the nature of the dust cycle and of the stellar populations in these galaxies. The derived IR composite template is consistent with the galaxies in the studied sample. A delayed star formation history with τmain = 500 Myr is slightly favored by the statistical analysis as compared to a delayed with a final burst or a continuous star formation history. The position of the sample in the star formation rate (SFR) versus Mstar diagram is consistent with previous papers. The redshift evolution of the log Mstar versus AFUV relation is in agreement with an evolution in redshift of this relation. This evolution is necessary to explain the cosmic evolution of the average dust attenuation of galaxies. Evolution is also observed in the Ldust/LFUV (IRX) versus UV slope βFUV diagram: younger galaxies have bluer βFUV. We modeled the shift of galaxies in the IRX versus the βFUV diagram with the mass-weighted age as a free parameter, and we provide an equation to make predictions. The large sample studied in this paper is generally consistent with models that assume rapid dust formation from supernovae and removal of dust by outflows and supernovae blasts. However, we find that high mass dusty star-forming galaxies cannot be explained by the models.

We present the average [C ii] 158 mu m emission line sizes of UV-bright star-forming galaxies at z similar to 7. Our results are derived from a stacking analysis of [C ii] 158 mu m emission lines and dust continua observed by the Atacama Large Millimeter/submillimeter Array (ALMA), taking advantage of the large program Reionization Era Bright Emission Line Survey. We find that the average [C ii] emission at z similar to 7 has an effective radius r ( e ) of 2.2 +/- 0.2 kpc. It is greater than or similar to 2x larger than the dust continuum and the rest-frame UV emission, in agreement with recently reported measurements for z less than or similar to 6 galaxies. Additionally, we compared the average [C ii] size with 4 < z < 6 galaxies observed by the ALMA Large Program to INvestigate [C ii] at Early times (ALPINE). By analyzing [C ii] sizes of 4 < z < 6 galaxies in two redshift bins, we find an average [C ii] size of r (e) = 2.2 +/- 0.2 kpc and r (e) = 2.5 +/- 0.2 kpc for z similar to 5.5 and z similar to 4.5 galaxies, respectively. These measurements show that star-forming galaxies, on average, show no evolution in the size of the [C ii] 158 mu m emitting regions at redshift between z similar to 7 and z similar to 4. This finding suggests that the star-forming galaxies could be morphologically dominated by gas over a wide redshift range.

Star-forming galaxies are composed of various types of galaxies. However, the luminosity functions at z ≳ 4–5 suggest that most galaxies have a relatively low stellar mass (log M_(star) ∼ 10) and a low dust attenuation (A_(FUV) ∼ 1.0). The physical properties of these objects are quite homogeneous. We used an approach where we combined their rest-frame far-infrared and submillimeter emissions and utilized the universe and the redshift as a spectrograph to increase the amount of information in a collective way. From a subsample of 27 ALMA-detected galaxies at z > 4.5, we built an infrared spectral energy distribution composite template. It was used to fit, with CIGALE, the 105 galaxies (detections and upper limits) in the sample from the far-ultraviolet to the far-infrared. The derived physical parameters provide information to decipher the nature of the dust cycle and of the stellar populations in these galaxies. The derived IR composite template is consistent with the galaxies in the studied sample. A delayed star formation history with τ_(main) = 500 Myr is slightly favored by the statistical analysis as compared to a delayed with a final burst or a continuous star formation history. The position of the sample in the star formation rate (SFR) versus M_(star) diagram is consistent with previous papers. The redshift evolution of the log M_(star) versus A_(FUV) relation is in agreement with an evolution in redshift of this relation. This evolution is necessary to explain the cosmic evolution of the average dust attenuation of galaxies. Evolution is also observed in the L_(dust)/L_(FUV) (IRX) versus UV slope β_(FUV) diagram: younger galaxies have bluer β_(FUV). We modeled the shift of galaxies in the IRX versus the β_(FUV) diagram with the mass-weighted age as a free parameter, and we provide an equation to make predictions. The large sample studied in this paper is generally consistent with models that assume rapid dust formation from supernovae and removal of dust by outflows and supernovae blasts. However, we find that high mass dusty star-forming galaxies cannot be explained by the models.

We present the average [CII] $158\,\rm{μm}$ emission line sizes of UV-bright star-forming galaxies at $z\sim7$. Our results are derived from a stacking analysis of [CII] $158\,\rm{μm}$ emission lines and dust continua observed by ALMA, taking advantage of the large program Reionization Era Bright Emission Line Survey (REBELS). We find that the average [CII] emission at $z\sim7$ has an effective radius $r_e$ of $2.2\pm0.2\,\rm{kpc}$. It is $\gtrsim2\times$ larger than the dust continuum and the rest-frame UV emission, in agreement with recently reported measurements for $z\lesssim6$ galaxies. Additionally, we compared the average [CII] size with $4, 9pages, 4 figures, submitted to ApJ; minor corrections were made for typos in the author list and the title

International audience; Star formation rate (SFR) measurements at z > 4 have relied mostly on the rest-frame far-ultraviolet (FUV) observations. The corrections for dust attenuation based on the IRX-β relation are highly uncertain and are still debated in the literature. Hence, rest-frame far-infrared (FIR) observations are necessary to constrain the dust-obscured component of the SFR. In this paper, we exploit the rest-frame FIR continuum observations collected by the ALMA Large Program to INvestigate [CII] at Early times (ALPINE) to directly constrain the obscured SFR in galaxies at 4.4 < z < 5.9. We used stacks of continuum images to measure average infrared luminosities taking both detected and undetected sources into account. Based on these measurements, we measured the position of the main sequence of star-forming galaxies and the specific SFR (sSFR) at z ∼ 4.5 and z ∼ 5.5. We find that the main sequence and sSFR do not significantly evolve between z ∼ 4.5 and z ∼ 5.5, as opposed to lower redshifts. We developed a method to derive the obscured SFR density (SFRD) using the stellar masses or FUV-magnitudes as a proxy of FIR fluxes measured on the stacks and combining them with the galaxy stellar mass functions and FUV luminosity functions from the literature. We obtain consistent results independent of the chosen proxy. We find that the obscured fraction of SFRD is decreasing with increasing redshift, but even at z ∼ 5.5 it constitutes around 61% of the total SFRD.

The ALMA-ALPINE [CII] survey is aimed at characterizing the properties of a sample of normal star-forming galaxies (SFGs). The ALMA Large Program to INvestigate (ALPINE) features 118 galaxies observed in the [CII]-158 μm line and far infrared (FIR) continuum emission during the period of rapid mass assembly, right after the end of the HI reionization, at redshifts of 4 < z < 6. We present the survey science goals, the observational strategy, and the sample selection of the 118 galaxies observed with ALMA, with an average beam minor axis of about 0.85″, or ∼5 kpc at the median redshift of the survey. The properties of the sample are described, including spectroscopic redshifts derived from the UV-rest frame, stellar masses, and star-formation rates obtained from a spectral energy distribution (SED) fitting. The observed properties derived from the ALMA data are presented and discussed in terms of the overall detection rate in [CII] and FIR continuum, with the observed signal-to-noise distribution. The sample is representative of the SFG population in the main sequence at these redshifts. The overall detection rate in [CII] is 64% for a signal-to-noise ratio (S/N) threshold larger than 3.5 corresponding to a 95% purity (40% detection rate for S/N > 5). Based on a visual inspection of the [CII] data cubes together with the large wealth of ancillary data, we find a surprisingly wide range of galaxy types, including 40% that are mergers, 20% extended and dispersion-dominated, 13% compact, and 11% rotating discs, with the remaining 16% too faint to be classified. This diversity indicates that a wide array of physical processes must be at work at this epoch, first and foremost, those of galaxy mergers. This paper sets a reference sample for the gas distribution in normal SFGs at 4 < z < 6, a key epoch in galaxy assembly, which is ideally suited for studies with future facilities, such as the James Webb Space Telescope (JWST) and the Extremely Large Telescopes (ELTs).

Mid- and far-infrared (IR) photometric and spectroscopic observations are fundamental to a full understanding of the dust-obscured Universe and the evolution of both star formation and black hole accretion in galaxies. In this work, using the specifications of the SPace Infrared telescope for Cosmology and Astrophysics (SPICA) as a baseline, we investigate the capability to study the dust-obscured Universe of mid- and far-IR photometry at 34 and 70 mu m and low-resolution spectroscopy at 17-36 mu m using the state-of-the-art Spectro-Photometric Realisations of Infrared-selected Targets at all-z (SPRITZ) simulation. This investigation is also compared to the expected performance of the Origins Space Telescope and the Galaxy Evolution Probe. The photometric view of the Universe of a SPICA-like mission could cover not only bright objects (e.g. L-IR > 10(12) L-circle dot) up to z = 10, but also normal galaxies (L-IR < 10(11) L-circle dot) up to z similar to 4. At the same time, the spectroscopic observations of such mission could also allow us to estimate the redshifts and study the physical properties for thousands of star-forming galaxies and active galactic nuclei by observing the polycyclic aromatic hydrocarbons and a large set of IR nebular emission lines. In this way, a cold, 2.5-m size space telescope with spectro-photometric capability analogous to SPICA, could provide us with a complete three-dimensional (i.e. images and integrated spectra) view of the dust-obscured Universe and the physics governing galaxy evolution up to z similar to 4.

We present the [C II] 158 mu m line luminosity functions (LFs) at z similar to 4-6 using the ALMA observations of 118 sources, which are selected to have UV luminosity M-1500A < -20.2 and optical spectroscopic redshifts in COSMOS and ECDF-S. Of the 118 targets, 75 have significant [C II] detections and 43 are upper limits. This is by far the largest sample of [C II] detections, which allows us to set constraints on the volume density of [C II] emitters at z similar to 4-6. But because this is a UV-selected sample, we are missing [C II]-bright but UV-faint sources, making our constraints strict lower limits. Our derived LFs are statistically consistent with the z similar to 0 [C II] LF at 10(8.25)-10(9.75)L. We compare our results with the upper limits of the [C II] LF derived from serendipitous sources in the ALPINE maps. We also infer the [C II] LFs based on published far-IR and CO LFs at z similar to 4-6. Combining our robust lower limits with these additional estimates, we set further constraints on the true number density of [C II] emitters at z similar to 4-6. These additional LF estimates are largely above our LF at L-[CII] > 10(9)L, suggesting that UV-faint but [C II]-bright sources likely make significant contributions to the [C II] emitter volume density. When we include all the LF estimates, we find that available model predictions underestimate the number densities of [C II] emitters at z similar to 4-6. Finally, we set a constraint on the molecular gas mass density at z similar to 4-6, with rho(mol) similar to (2-7) x 10(7)M Mpc(-3). This is broadly consistent with previous studies.

We present the ancillary data and basic physical measurements for the galaxies in the ALMA Large Program to Investigate C+ at Early Times (ALPINE) survey - the first large multi-wavelength survey which aims at characterizing the gas and dust properties of 118 main-sequence galaxies at redshifts 4.4 < z < 5.9 via the measurement of [CII]-emission at 158 micro-meter (64% at >3.5$\sigma$) and the surrounding far-infrared (FIR) continuum in conjunction with a wealth of optical and near-infrared data. We outline in detail the spectroscopic data and selection of the galaxies as well as the ground- and space-based imaging products. In addition, we provide several basic measurements including stellar masses, star formation rates (SFR), rest-frame ultra-violet (UV) luminosities, UV continuum slopes ($\beta$), and absorption line redshifts, as well as H-alpha emission derived from Spitzer colors. We find that the ALPINE sample is representative of the 4 < z < 6 galaxy population selected by photometric methods and only slightly biased towards bluer colors ($\Delta\beta$ ~ 0.2). Using [CII] as tracer of the systemic redshift (confirmed for one galaxy at z=4.5 out of 118 for which we obtained optical [OII]$\lambda$3727A emission), we confirm red shifted Ly-alpha emission and blue shifted absorption lines similar to findings at lower redshifts. By stacking the rest-frame UV spectra in the [CII] rest-frame we find that the absorption lines in galaxies with high specific SFR are more blue shifted, which could be indicative of stronger winds and outflows., Comment: 48 pages, 33 figures, 7 tables (including Appendix), accepted for publication in ApJS