- ID:
- ivo://CDS.VizieR/J/A+A/575/A30
- Title:
- HIFLUGCS XMM/Chandra cross-calibration
- Short Name:
- J/A+A/575/A30
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Robust X-ray temperature measurements of the intracluster medium (ICM) of galaxy clusters require an accurate energy-dependent effective area calibration. Since the hot gas X-ray emission of galaxy clusters does not vary on relevant timescales, they are excellent cross-calibration targets. Moreover, cosmological constraints from clusters rely on accurate gravitational mass estimates, which in X-rays strongly depend on cluster gas temperature measurements. Therefore, systematic calibration differences may result in biased, instrument-dependent cosmological constraints. This is of special interest in light of the tension between the Planck results of the primary temperature anisotropies of the cosmic microwave background (CMB) and Sunyaev-Zel'dovich-plus-X-ray cluster-count analyses. We quantify in detail the systematics and uncertainties of the cross-calibration of the effective area between five X-ray instruments, EPIC-MOS1/MOS2/PN onboard XMM-Newton and ACIS-I/S onboard Chandra, and the influence on temperature measurements. Furthermore, we assess the impact of the cross-calibration uncertainties on cosmology. Using the HIFLUGCS sample, consisting of the 64 X-ray brightest galaxy clusters, we constrain the ICM temperatures through spectral fitting in the same, mostly isothermal regions and compare the different instruments. We use the stacked residual ratio method to evaluate the cross-calibration uncertainties between the instruments as a function of energy. Our work is an extension to a previous one using X-ray clusters by the International Astronomical Consortium for High Energy Calibration (IACHEC) and is carried out in the context of IACHEC. Performing spectral fitting in the full energy band, (0.7-7)keV, as is typical of the analysis of cluster spectra, we find that best-fit temperatures determined with XMM-Newton/EPIC are significantly lower than Chandra/ACIS temperatures. This confirms the previous IACHEC results obtained with older calibrations with high precision. The difference increases with temperature, and we quantify this dependence with a fitting formula. For instance, at a cluster temperature of 10keV, EPIC temperatures are on average 23% lower than ACIS temperatures. We also find systematic differences between the three XMM-Newton/EPIC instruments, with the PN detector typically estimating the lowest temperatures. Testing the cross-calibration of the energy-dependence of the effective areas in the soft and hard energy bands, (0.7-2)keV and (2-7)keV, respectively, we confirm the previously indicated relatively good agreement between all instruments in the hard and the systematic differences in the soft band. We provide scaling relations to convert between the different instruments based on the effective area, gas temperature, and hydrostatic mass. We demonstrate that effects like multitemperature structure and different relative sensitivities of the instruments at certain energy bands cannot explain the observed differences. We conclude that using XMM-Newton/EPIC instead of Chandra/ACIS to derive full energy band temperature profiles for cluster mass determination results in an 8% shift toward lower {Omega}_M_ values and <1% change of {sigma}_8_ values in a cosmological analysis of a complete sample of galaxy clusters. Such a shift alone is insufficient to significantly alleviate the tension between Planck CMB primary anisotropies and Sunyaev-Zel'dovich-plus-XMM-Newton cosmological constraints.
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Search Results
- ID:
- ivo://CDS.VizieR/J/MNRAS/437/2017
- Title:
- HI-galaxy cross-correlation at z<~1
- Short Name:
- J/MNRAS/437/2017
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present a new optical spectroscopic survey of 1777 'star-forming' ('SF') and 366 'non-star-forming' ('non-SF') galaxies at redshifts z~0-1 (2143 in total), 22 AGN and 423 stars, observed by instruments such as the Deep Imaging Multi-Object Spectrograph, the Visible Multi-Object Spectrograph and the Gemini Multi-Object Spectrograph, in three fields containing five quasi-stellar objects (QSOs) with Hubble Space Telescope (HST) ultraviolet spectroscopy. We also present a new spectroscopic survey of 173 'strong' (10^14^<=N_HI_<~10^17^cm^-2^) and 496 'weak' (10^13^<~N_HI_<10^14^cm^-2^) intervening HI (Ly{alpha}) absorption-line systems at z<~1 (669 in total), observed in the spectra of eight QSOs at z~1 by the Cosmic Origins Spectrograph and the Faint Object Spectrograph on the HST. Combining these new data with previously published galaxy catalogues such as the Very Large Telescope Visible Multi-Object Spectrograph Deep Survey and the Gemini Deep Deep Survey, we have gathered a sample of 654 HI absorption systems and 17509 galaxies at transverse scales <~50Mpc, suitable for a two-point correlation function analysis. We present observational results on the HI-galaxy ({xi}_ag_) and galaxy-galaxy ({xi}_gg_) correlations at transverse scales r_perp_<~10Mpc, and the HI-HI autocorrelation ({xi}_aa_) at transverse scales r_perp_<~2Mpc.
- ID:
- ivo://CDS.VizieR/J/A+A/597/A114
- Title:
- Hi-GAL cluster candidates physical properties
- Short Name:
- J/A+A/597/A114
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The aims are to investigate the clustering of the far-infrared sources from the Herschel infrared Galactic Plane Survey (Hi-GAL) in the Galactic longitude range of -71 to 67{deg}. These clumps, and their spatial distribution, are an imprint of the original conditions within a molecular cloud. This will produce a catalogue of over-densities. The minimum spanning tree (MST) method was used to identify the over-densities in two dimensions. The catalogue was further refined by folding in heliocentric distances, resulting in more reliable over-densities, which are cluster candidates. We found 1633 over-densities with more than ten members. Of these, 496 are defined as cluster candidates because of the reliability of the distances, with a further 1,137 potential cluster candidates. The spatial distributions of the cluster candidates are different in the first and fourth quadrants, with all clusters following the spiral structure of the Milky Way. The cluster candidates are fractal. The clump mass functions of the clustered and isolated are statistically indistinguishable from each other and are consistent with Kroupa's initial mass function.
- ID:
- ivo://CDS.VizieR/J/MNRAS/471/100
- Title:
- Hi-GAL compact source catalog. -71.0<l<67.0
- Short Name:
- J/MNRAS/471/100
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Hi-GAL (Herschel InfraRed Galactic Plane Survey) is a large-scale survey of the Galactic plane, performed with Herschelin five infrared continuum bands between 70 and 500{mu}m. We present a band-merged catalogue of spatially matched sources and their properties derived from fits to the spectral energy distributions (SEDs) and heliocentric distances, based on the photometric catalogues presented in Molinari et al., covering the portion of Galactic plane -71.0{deg}<l<67.0{deg}. The band-merged catalogue contains 100 922 sources with a regular SED, 24584 of which show a 70-{mu}m counterpart and are thus considered protostellar, while the remainder are considered starless. Thanks to this huge number of sources, we are able to carry out a preliminary analysis of early stages of star formation, identifying the conditions that characterize different evolutionary phases on a statistically significant basis. We calculate surface densities to investigate the gravitational stability of clumps and their potential to form massive stars. We also explore evolutionary status metrics such as the dust temperature, luminosity and bolometric temperature, finding that these are higher in protostellar sources compared to pre-stellar ones. The surface density of sources follows an increasing trend as they evolve from pre-stellar to protostellar, but then it is found to decrease again in the majority of the most evolved clumps. Finally, we study the physical parameters of sources with respect to Galactic longitude and the association with spiral arms, finding only minor or no differences between the average evolutionary status of sources in the fourth and first Galactic quadrants, or between 'on-arm' and 'interarm' positions.
- ID:
- ivo://CDS.VizieR/J/A+A/591/A149
- Title:
- Hi-GAL. inner Milky Way: +68>=l>=70
- Short Name:
- J/A+A/591/A149
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the first public release of high-quality data products (DR1) from Hi-GAL, the Herschel infrared Galactic Plane Survey. Hi-GAL is the keystone of a suite of continuum Galactic plane surveys from the near-IR to the radio and covers five wavebands at 70, 160, 250, 350 and 500{mu}m, encompassing the peak of the spectral energy distribution of cold dust for 8<~T<~50K. This first Hi-GAL data release covers the inner Milky Way in the longitude range 68{deg}>~l>~-70{deg} in a |b|<=1{deg} latitude strip. Photometric maps have been produced with the ROMAGAL pipeline, which optimally capitalizes on the excellent sensitivity and stability of the bolometer arrays of the Herschel PACS and SPIRE photometric cameras. It delivers images of exquisite quality and dynamical range, absolutely calibrated with Planck and IRAS, and recovers extended emission at all wavelengths and all spatial scales, from the point-spread function to the size of an entire 2{deg}x2{deg} "tile" that is the unit observing block of the survey. The compact source catalogues were generated with the CuTEx algorithm, which was specifically developed to optimise source detection and extraction in the extreme conditions of intense and spatially varying background that are found in the Galactic plane in the thermal infrared. Hi-GAL DR1 images are cirrus noise limited and reach the 1{sigma}-rms predicted by the Herschel Time Estimators for parallel-mode observations at 60"/s scanning speed in relatively low cirrus emission regions. Hi-GAL DR1 images will be accessible through a dedicated web-based image cutout service. The DR1 Compact Source Catalogues are delivered as single-band photometric lists containing, in addition to source position, peak, and integrated flux and source sizes, a variety of parameters useful to assess the quality and reliability of the extracted sources. Caveats and hints to help in this assessment are provided. Flux completeness limits in all bands are determined from extensive synthetic source experiments and greatly depend on the specific line of sight along the Galactic plane because the background strongly varies as a function of Galactic longitude. Hi-GAL DR1 catalogues contain 120581, 291858, 280143, 161946, and 85811 compact sources in the five bands.
- ID:
- ivo://CDS.VizieR/J/A+A/594/A58
- Title:
- Hi-GAL l=224deg region CO(1-0) data cubes
- Short Name:
- J/A+A/594/A58
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Stars form in dense, dusty structures, which are embedded in larger clumps of molecular clouds often showing a clear filamentary structure on large scales (>1pc). The origin (e.g., turbulence or gravitational instabilities) and evolution of these filaments, as well as their relation to clump and core formation, are not yet fully understood. A large sample of both starless and protostellar clumps can now be found in the Herschel Hi-GAL (Herschel Infrared GALactic Plane Survey) key project, which also provides striking images of the filamentary structure of the parent molecular clouds. Recent results indicate that populations of clumps on and off filaments may differ. One of the best studied regions in the Hi-GAL survey can be observed toward the l=224{deg} field. Here, a filamentary region has been studied and it has been found that protostellar clumps are mostly located along the main filament, whereas starless clumps are detected off this filament and are instead found on secondary, less prominent filaments. We want to investigate this segregation effect and how it may affect the clumps properties. We mapped the ^12^CO(1-0) line and its main three isotopologues toward the two most prominent filaments observed toward the l=224{deg} field using the Mopra radio telescope, in order to set observational constraints on the dynamics of these structures and the associated starless and protostellar clumps. Compared to the starless clumps, the protostellar clumps are more luminous, more turbulent and lie in regions where the filamentary ambient gas shows larger linewidths. We see evidence of gas flowing along the main filament, but we do not find any signs of accretion flow from the filament onto the Hi-GAL clumps. We analyze the radial column density profile of the filaments and their gravitational stability. The more massive and highly fragmented main filament appears to be thermally supercritical and gravitationally bound, assuming that all of the non-thermal motion is contributing thermal-like support, suggesting a later stage of evolution compared to the secondary filament. The status and evolutionary phase of the Hi-GAL clumps would then appear to correlate with that of the host filament.
- ID:
- ivo://irsa.ipac/Herschel/Catalog/Hi-GAL/Hi-GAL_250
- Title:
- Hi-GAL 250 micron Photometric Catalog
- Short Name:
- Hi-GAL_250
- Date:
- 01 Oct 2018 20:27:20
- Publisher:
- NASA/IPAC Infrared Science Archive
- Description:
- The Herschel infrared Galactic Plane Survey (Hi-GAL) covers the Galactic plane at five wavelengths from 70 to 500 microns. Hi-GAL DR1 is limited to the inner Milky Way in the longitude range +68d > l > -70d and latitude range 1d > b > -1d. The generation of the Hi-GAL photometric catalogs is discussed in detail in Molinari et al. (2016).
- ID:
- ivo://irsa.ipac/Herschel/Catalog/Hi-GAL/Hi-GAL_160
- Title:
- Hi-GAL 160 micron Photometric Catalog
- Short Name:
- Hi-GAL_160
- Date:
- 01 Oct 2018 20:27:20
- Publisher:
- NASA/IPAC Infrared Science Archive
- Description:
- The Herschel infrared Galactic Plane Survey (Hi-GAL) covers the Galactic plane at five wavelengths from 70 to 500 microns. Hi-GAL DR1 is limited to the inner Milky Way in the longitude range +68d > l > -70d and latitude range 1d > b > -1d. The generation of the Hi-GAL photometric catalogs is discussed in detail in Molinari et al. (2016).
- ID:
- ivo://irsa.ipac/Herschel/Catalog/Hi-GAL/Hi-GAL_70
- Title:
- Hi-GAL 70 micron Photometric Catalog
- Short Name:
- Hi-GAL_70
- Date:
- 01 Oct 2018 20:27:20
- Publisher:
- NASA/IPAC Infrared Science Archive
- Description:
- The Herschel infrared Galactic Plane Survey (Hi-GAL) covers the Galactic plane at five wavelengths from 70 to 500 microns. Hi-GAL DR1 is limited to the inner Milky Way in the longitude range +68d > l > -70d and latitude range 1d > b > -1d. The generation of the Hi-GAL photometric catalogs is discussed in detail in Molinari et al. (2016).
- ID:
- ivo://irsa.ipac/Herschel/Catalog/Hi-GAL/Hi-GAL_350
- Title:
- Hi-GAL 350 micron Photometric Catalog
- Short Name:
- Hi-GAL_350
- Date:
- 01 Oct 2018 20:27:20
- Publisher:
- NASA/IPAC Infrared Science Archive
- Description:
- The Herschel infrared Galactic Plane Survey (Hi-GAL) covers the Galactic plane at five wavelengths from 70 to 500 microns. Hi-GAL DR1 is limited to the inner Milky Way in the longitude range +68d > l > -70d and latitude range 1d > b > -1d. The generation of the Hi-GAL photometric catalogs is discussed in detail in Molinari et al. (2016).