- ID:
- ivo://CDS.VizieR/J/A+AS/117/39
- Title:
- Hickson Compact Groups of Galaxies I.
- Short Name:
- J/A+AS/117/39
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The Far Infrared (FIR) properties of galaxies which are members of compact groups bear relevant information on the dynamical status and the physical properties of these structures. All studies published so far have been undermined by the poor sensitivity and spatial resolution of the IRAS-PSC and IRAS Sky Survey data. We used the HIRAS software available at the IRAS server at the Laboratory for Space Research in Groningen to fully exploit the redundancy of the IRAS data and to approach the theoretical diffraction limit of IRAS. Among the 97 groups which were observed by IRAS, 62 were detected in at least one band, while reliable upper limits were derived for all the others. Among the detected groups, 49 were fully or partially resolved, i.e. it was possible to discriminate which member or members emit most of the FIR light. At 60{mu}m, for instance, 87 individual sources were detected in 62 groups. In order to ease the comparison with data obtained at other wavelengths - and in particular in the X and radio domains - we give co-added and HIRAS maps for all the detected groups.
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- ID:
- ivo://CDS.VizieR/VII/213
- Title:
- Hickson's Compact groups of Galaxies
- Short Name:
- VII/213
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The catalog of groups (file "groups.dat") is a list of 100 compact groups of galaxies identified by a systematic search of the Palomar Observatory Sky Survey red prints. Each group contains four or more galaxies, has an estimated mean surface brightness brighter than 26.0 magnitude per arcsec^2^ and satisfies an isolation criterion. Dynamical parameters were derived for 92 of the 100 groups, which are listed in file "dynamics.dat"; the Hubble constant was assumed to be Ho=100km/s/Mpc. Data about individual galaxies in these groups are merged into the "galaxies.dat" file; these data include photometric parameters, morphology, redshifts and absolute magnitudes originally published in four different papers. They result from CCD observations at CFHT (Canada-France-Hawaii Telescope) in 1983-1985. Redshifts were observed at the 1.5m telescope of the F.L. Whipple Observatory on Mt. Hopkins, Arizona, over the period 1984-1986, in wavelength range 470-710nm; the remaining fainter galaxies were observed with the CFHT.
- ID:
- ivo://CDS.VizieR/J/AJ/133/1104
- Title:
- HI 21cm observations of Pegasus galaxies
- Short Name:
- J/AJ/133/1104
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present neutral hydrogen observations of 54 galaxies in the Pegasus Cluster. The observations include single-dish HI measurements, obtained with the Arecibo telescope for all 54 galaxies in the sample, as well as HI images obtained with the Very Large Array (VLA) for 10 of these.
- ID:
- ivo://CDS.VizieR/J/A+A/650/A76
- Title:
- HI content in Coma cluster substructure
- Short Name:
- J/A+A/650/A76
- Date:
- 22 Feb 2022
- Publisher:
- CDS
- Description:
- Galaxy clusters are some of largest structures in the universe. These very dense environments tend to be home to higher numbers of evolved galaxies than found in lower-density environments. It is well known that dense environments can influence the evolution of galaxies through the removal of the neutral gas (HI) reservoirs that fuel star formation. It is unclear which environment has a stronger effect: the local environment (i.e. the substructure within the cluster), or the cluster itself. Using the new HI data from the Westerbork Coma Survey, we explore the average HI content of galaxies across the cluster comparing galaxies that reside in substructure to those that do not. We applied the Dressler-Shectman test to our newly compiled redshift catalogue of the Coma cluster to search for substructure. With so few of the Coma galaxies directly detected in HI, we used the HI stacking technique to probe the average HI content below what can be directly detected. Using the Dressler-Shectman test, we find 15 substructures within the footprint of the Westerbork Coma Survey. We compare the average HI content for galaxies within substructure to those not in substructure. Using the HI stacking technique, we find that those Coma galaxies not detected in HI are more than 10-50 times more HI deficient than expected, which supports the scenario of an extremely efficient and rapid quenching mechanism. By studying the galaxies that are not directly detected in HI, we also find Coma to be more HI deficient than previously thought.
- ID:
- ivo://CDS.VizieR/J/A+A/659/A94
- Title:
- HI-detected Coma and field galaxies properties
- Short Name:
- J/A+A/659/A94
- Date:
- 14 Mar 2022 06:46:08
- Publisher:
- CDS
- Description:
- We present the blind Westerbork Coma Survey probing the HI content of the Coma galaxy cluster with the Westerbork Synthesis Radio Telescope. The survey covers the inner ~1Mpc around the cluster centre, extending out to 1.5Mpc towards the south-western NGC 4839 group. The survey probes the atomic gas in the entire Coma volume down to a sensitivity of ~10^19^cm^-2^ and 10^8^M_{sun}_. Combining automated source finding with source extraction at optical redshifts and visual verification, we obtained 40 HI detections of which 24 are new. Over half of the sample displays perturbed HI morphologies indicative of an ongoing interaction with the cluster environment. With the use of ancillary UV and mid-IR, data we measured their stellar masses and star formation rates and compared the HI properties to a set of field galaxies spanning a similar stellar mass and star formation rate range. We find that ~75% of HI-selected Coma galaxies have simultaneously enhanced star formation rates (by ~0.2dex) and are HI deficient (by ~0.5dex) compared to field galaxies of the same stellar mass. According to our toy model, the simultaneous HI deficiency and enhanced star formation activity can be attributed to either HI stripping of already highly star forming galaxies on a very short timescale, while their H_2_ content remains largely unaffected, or to HI stripping coupled to a temporary boost of the HI-to-H_2_ conversion, causing a brief starburst phase triggered by ram pressure before eventually quenching the galaxy.
- 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.
- ID:
- ivo://CDS.VizieR/J/MNRAS/471/1766
- Title:
- High-redshift AGN feedback in SZ clusters
- Short Name:
- J/MNRAS/471/1766
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present a study of active galactic nucleus (AGN) feedback at higher redshifts (0.3<z<1.2) using Sunyaev-Zel'dovich selected samples of clusters from the South Pole Telescope and Atacama Cosmology Telescope surveys. In contrast to studies of nearby systems, we do not find a separation between cooling flow (CF) clusters and non-CF clusters based on the radio luminosity of the central radio source (cRS). This lack may be due to the increased incidence of galaxy-galaxy mergers at higher redshift that triggers AGN activity. In support of this scenario, we find evidence for evolution in the radio-luminosity function of the cRS, while the lower luminosity sources do not evolve much, the higher luminosity sources show a strong increase in the frequency of their occurrence at higher redshifts. We interpret this evolution as an increase in high-excitation radio galaxies (HERGs) in massive clusters at z>0.6, implying a transition from HERG-mode accretion to lower power low-excitation radio galaxy (LERG)-mode accretion at intermediate redshifts. Additionally, we use local radio-to-jet power scaling relations to estimate feedback power and find that half of the CF systems in our sample probably have enough heating to balance cooling. However, we postulate that the local relations are likely not well suited to predict feedback power in high-luminosity HERGs, as they are derived from samples composed mainly of lower luminosity LERGs.
- ID:
- ivo://CDS.VizieR/J/A+A/442/841
- Title:
- High-redshift galaxy clusters
- Short Name:
- J/A+A/442/841
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present new spectroscopic data in the field of five high-redshift (z>~0.6) candidate galaxy clusters, drawn from the EIS Cluster Candidate Catalog. A total of 327 spectra were obtained using FORS1 at the VLT, out of which 266 are galaxies with secure redshifts. In this paper, we use these data for confirming the existence of overdensities in redshift space at the approximate same location as the matched-filter detections in the projected distribution of galaxies from the EIS I-band imaging survey. The spectroscopic redshifts, associated to these overdensities, are consistent but, in general, somewhat lower than those predicted by the matched-filter technique. Combining the systems presented here with those analyzed earlier, we have spectroscopically confirmed a total of nine overdensities in the redshift range 0.6<z<1.3, providing an important first step in building an optically-selected, high-redshift sample for more detailed studies, complementing those based on the few available X-ray selected systems.
- ID:
- ivo://CDS.VizieR/J/ApJ/734/68
- Title:
- High redshift galaxy clusters in deep fields
- Short Name:
- J/ApJ/734/68
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Identification of high-redshift clusters is important for studies of cosmology and cluster evolution. Using photometric redshifts of galaxies, we identify 631 clusters from the Canada-France-Hawaii Telescope (CFHT) wide field, 202 clusters from the CFHT deep field, 187 clusters from the Cosmic Evolution Survey (COSMOS) field, and 737 clusters from the Spitzer Wide-area InfraRed Extragalactic Survey (SWIRE) field. The redshifts of these clusters are in the range 0.1<~z<~1.6. Merging these cluster samples gives 1644 clusters in the four survey fields, of which 1088 are newly identified and more than half are from the large SWIRE field. Among 228 clusters of z>=1, 191 clusters are newly identified, and most of them from the SWIRE field. With this large sample of high-redshift clusters, we study the color evolution of the brightest cluster galaxies (BCGs).
- ID:
- ivo://CDS.VizieR/J/ApJ/862/156
- Title:
- High-z galaxy candidates in the HFF cluster fields
- Short Name:
- J/ApJ/862/156
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Acting as powerful gravitational lenses, the strong lensing galaxy clusters of the deep Hubble Frontier Fields (HFF) program permit access to lower-luminosity galaxies lying at higher redshifts than hitherto possible. We analyzed the HFF to measure the volume density of Lyman-break galaxies at z>4.75 by identifying a complete and reliable sample up to z~10. A marked deficit of such galaxies was uncovered in the highly magnified regions of the clusters relative to their outskirts, implying that the magnification of the sky area dominates over additional faint galaxies magnified above the flux limit. This negative magnification bias is consistent with a slow rollover at the faint end of the UV luminosity function and it indicates a preference for Bose-Einstein condensate dark matter with a light boson mass of m_B_~10^-22^eV over standard cold dark matter. We emphasize that measuring the magnification bias requires no correction for multiply-lensed images (with typically three or more images per source), whereas directly reconstructing the luminosity function will lead to an overestimate unless such images can be exhaustively matched up, especially at the faint end that is only accessible in the strongly lensed regions. In addition, we detected a distinctive downward transition in galaxy number density at z>~8, which may be linked to the relatively late reionization reported by Planck. Our results suggests that JWST will likely peer into an "abyss" with essentially no galaxies detected in deep NIR imaging at z>10.
