161 research outputs found
Optimization and Quality Assessment of Baryon Pasting for Intracluster Gas using the Borg Cube Simulation
Synthetic datasets generated from large-volume gravity-only simulations are
an important tool in the calibration of cosmological analyses. Their creation
often requires accurate inference of baryonic observables from the dark matter
field. We explore the effectiveness of a baryon pasting algorithm in providing
precise estimations of three-dimensional gas thermodynamic properties based on
gravity-only simulations. We use the Borg Cube, a pair of simulations
originating from identical initial conditions, with one run evolved as a
gravity-only simulation, and the other incorporating non-radiative
hydrodynamics. Matching halos in both simulations enables comparisons of gas
properties on an individual halo basis. This comparative analysis allows us to
fit for the model parameters that yield the closest agreement between the gas
properties in both runs. To capture the redshift evolution of these parameters,
we perform the analysis at five distinct redshift steps, spanning from to
. We find that the investigated algorithm, utilizing information solely from
the gravity-only simulation, achieves few-percent accuracy in reproducing the
median intracluster gas pressure and density, albeit with a scatter of
approximately 20%, for cluster-scale objects up to . We measure the
scaling relation between integrated Compton parameter and cluster mass
(), and find that the imprecision of baryon pasting adds
less than 5% to the intrinsic scatter measured in the hydrodynamic simulation.
We provide best-fitting values and their redshift evolution, and discuss future
investigations that will be undertaken to extend this work.Comment: 14 pages, 8 figures, 3 tables; accepted in the Open Journal of
Astrophysic
The hydrostatic-to-lensing mass bias from resolved X-ray and optical-IR data
An accurate reconstruction of galaxy cluster masses is key to use this
population of objects as a cosmological probe. In this work we present a study
on the hydrostatic-to-lensing mass scaling relation for a sample of 53 clusters
whose masses were reconstructed homogeneously in a redshift range between and . The mass for each cluster was indeed inferred from
the mass profiles extracted from the X-ray and lensing data, without using a
priori observable-mass scaling relations. We assessed the systematic dispersion
of the masses estimated with our reference analyses with respect to other
published mass estimates. Accounting for this systematic scatter does not
change our main results, but enables the propagation of the uncertainties
related to the mass reconstruction method or used dataset. Our analysis gives a
hydrostatic-to-lensing mass bias of and no
evidence of evolution with redshift. These results are robust against possible
subsample differences
Estimation of the hydrostatic-to-lensing mass bias from resolved cluster masses
We present a study on the bias of hydrostatic masses with respect to lensing mass estimates for a sample of 53 clusters in a redshift range between z = 0.05 and 1.07. The M500 mass for each cluster was inferred from X-ray and lensing data, without using a priori observable-mass scaling relations. Cluster masses of our reference analysis were reconstructed homogeneously and we assess the systematic dispersion of those homogeneous masses with respect to other published mass estimates. We obtain an hydrostatic-to-lensing mass bias of (1 â b) = 0.74â0.07+0.08 and no significant evidence of evolution with redshift
NIKA2 observations of dust grain evolution from star-forming filament to T-Tauri disk: Preliminary results from NIKA2 observations of the Taurus B211/B213 filament
To understand the evolution of dust properties in molecular clouds in the
course of the star formation process, we constrain the changes in the dust
emissivity index from star-forming filaments to prestellar and protostellar
cores to T Tauri stars. Using the NIKA2 continuum camera on the IRAM 30~m
telescope, we observed the Taurus B211/B213 filament at 1.2\,mm and 2\,mm with
unprecedented sensitivity and used the resulting maps to derive the dust
emissivity index . Our sample of 105 objects detected in the map
of the B211/B213 filament indicates that, overall, decreases from
filament and prestellar cores () to protostellar cores
() to T-Tauri protoplanetary disk (). The
averaged dust emissivity index across the B211/B213 filament exhibits a
flat () profile. This may imply that dust grain sizes are
rather homogeneous in the filament, start to grow significantly in size only
after the onset of the gravitational contraction/collapse of prestellar cores
to protostars, reaching big sizes in T Tauri protoplanetary disks. This
evolution from the parent filament to T-Tauri disks happens on a timescale of
about 1-2~Myr.Comment: 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 Science
Towards the first mean pressure profile estimate with the NIKA2 Sunyaev-Zeldovich 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 38 galaxy clusters covering a wide mass
range at intermediate to high redshift. The measured SZ fluxes will be
essential to calibrate the SZ scaling relation and the galaxy clusters mean
pressure profile, needed for the cosmological exploitation of SZ surveys. We
present in this study a method to infer a mean pressure profile from cluster
observations. We have designed a pipeline encompassing the map-making and the
thermodynamical properties estimates from maps. We then combine all the
individual fits, propagating the uncertainties on integrated quantities, such
as or , and the intrinsic scatter coming from the deviation
to the standard self-similar model. We validate the proposed method on
realistic LPSZ-like cluster simulations.Comment: 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 Science
IAS/CEA Evolution of Dust in Nearby Galaxies (ICED): the spatially-resolved dust properties of NGC4254
We present the first preliminary results of the project \textit{ICED},
focusing on the face-on galaxy NGC4254. We use the millimetre maps observed
with NIKA2 at IRAM-30m, as part of the IMEGIN Guaranteed Time Large Program,
and of a wide collection of ancillary data (multi-wavelength photometry and gas
phase spectral lines) that are publicly available. We derive the global and
local properties of interstellar dust grains through infrared-to-radio spectral
energy distribution fitting, using the hierarchical Bayesian code HerBIE, which
includes the grain properties of the state-of-the-art dust model, THEMIS. Our
method allows us to get the following dust parameters: dust mass, average
interstellar radiation field, and fraction of small grains. Also, it is
effective in retrieving the intrinsic correlations between dust parameters and
interstellar medium properties. We find an evident anti-correlation between the
interstellar radiation field and the fraction of small grains in the centre of
NGC4254, meaning that, at strong radiation field intensities, very small
amorphous carbon grains are efficiently destroyed by the ultra-violet photons
coming from newly formed stars, through photo-desorption and sublimation. We
observe a flattening of the anti-correlation at larger radial distances, which
may be driven by the steep metallicity gradient measured in NGC4254.Comment: 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 Science
NIKA2 observations of 3 low-mass galaxy clusters at : pressure profile and - relation
Three galaxy clusters selected from the XXL X-ray survey at high redshift and
low mass ( and M) were
observed with NIKA2 to image their Sunyaev-Zel'dovich effect (SZ) signal. They
all present an SZ morphology, together with the comparison with X-ray and
optical data, that indicates dynamical activity related to merging events.
Despite their disturbed intracluster medium, their high redshifts, and their
low masses, the three clusters follow remarkably well the pressure profile and
the SZ flux-mass relation expected from standard evolution. This suggests that
the physics that drives cluster formation is already in place at
down to M.Comment: 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 Science
Exploring the interstellar medium of NGC 891 at millimeter wavelengths using the NIKA2 camera
In the framework of the IMEGIN Large Program, we used the NIKA2 camera on the
IRAM 30-m telescope to observe the edge-on galaxy NGC 891 at 1.15 mm and 2 mm
and at a FWHM of 11.1" and 17.6", respectively. Multiwavelength data enriched
with the new NIKA2 observations fitted by the HerBIE SED code (coupled with the
THEMIS dust model) were used to constrain the physical properties of the ISM.
Emission originating from the diffuse dust disk is detected at all wavelengths
from mid-IR to mm, while mid-IR observations reveal warm dust emission from
compact HII regions. Indications of mm excess emission have also been found in
the outer parts of the galactic disk. Furthermore, our SED fitting analysis
constrained the mass fraction of the small (< 15 Angstrom) dust grains. We
found that small grains constitute 9.5% of the total dust mass in the galactic
plane, but this fraction increases up to ~ 20% at large distances (|z| > 3 kpc)
from the galactic plane.Comment: 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 Science
The XXL Survey: XLIV. Sunyaev-Zelâdovich mapping of a low-mass cluster at z ⌠1: a multi-wavelength approach
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-Zelâdovich (SZ) effect, obtained with the NIKA2 camera, towards the cluster of galaxies XLSSC 102, a relatively low-mass system (M500ââŒâ2â
Ăâ
1014âMâ) at zâ=â0.97 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 âŒr500, 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 zââŒâ1, especially with low signal-to-noise ratio 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. This is promising for the study of high redshift clusters from the combination of eROSITA and high resolution SZ instruments and will complement the new generation of optical surveys from facilities such as LSST and Euclid
Flaring Stars in a Non-targeted mm-wave Survey with SPT-3G
We present a flare star catalog from four years of non-targeted
millimeter-wave survey data from the South Pole Telescope (SPT). The data were
taken with the SPT-3G camera and cover a 1500-square-degree region of the sky
from to in right ascension and
to in declination. This region was observed on a
nearly daily cadence from 2019-2022 and chosen to avoid the plane of the
galaxy. A short-duration transient search of this survey yields 111 flaring
events from 66 stars, increasing the number of both flaring events and detected
flare stars by an order of magnitude from the previous SPT-3G data release. We
provide cross-matching to Gaia DR3, as well as matches to X-ray point sources
found in the second ROSAT all-sky survey. We have detected flaring stars across
the main sequence, from early-type A stars to M dwarfs, as well as a large
population of evolved stars. These stars are mostly nearby, spanning 10 to 1000
parsecs in distance. Most of the flare spectral indices are constant or gently
rising as a function of frequency at 95/150/220 GHz. The timescale of these
events can range from minutes to hours, and the peak luminosities
range from to erg s in the SPT-3G frequency bands
- âŠ