- ID:
- ivo://CDS.VizieR/J/A+A/574/A126
- Title:
- HeViCS. XVIII. Star-forming dwarf galaxies
- Short Name:
- J/A+A/574/A126
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- To assess the effects of the cluster environment on the different components of the interstellar medium, we analyse the far-infrared (FIR) and submillimetre (submm) properties of a sample of star-forming dwarf galaxies detected by the Herschel Virgo Cluster Survey (HeViCS). We determine dust masses and dust temperatures by fitting a modified black body function to the spectral energy distributions (SEDs). Stellar and gas masses, star formation rates (SFRs), and metallicities are obtained from the analysis of a set of ancillary data. Dust is detected in 49 out of a total 140 optically identified dwarfs covered by the HeViCS field; considering only dwarfs brighter than m_B_=18mag, this gives a detection rate of 43%. After evaluating different emissivity indices, we find that the FIR-submm SEDs are best-fit by {beta}=1.5, with a median dust temperature T_d_=22.4K. Assuming {beta}=1.5, 67% of the 23 galaxies detected in all five Herschel bands show emission at 500{mu}m in excess of the modified black-body model. The fraction of galaxies with a submillimetre excess decreases for lower values of {beta}, while a similarly high fraction (54%) is found if a {beta}-free SED modelling is applied. The excess is inversely correlated with SFR and stellar masses. To study the variations in the global properties of our sample that come from environmental effects, we compare the Virgo dwarfs to other Herschel surveys, such as the Key Insights into Nearby Galaxies: Far-Infrared Survey with Herschel (KINGFISH), the Dwarf Galaxy Survey (DGS), and the HeViCS Bright Galaxy Catalogue (BGC). We explore the relations between stellar mass and HI fraction, specific star formation rate, dust fraction, gas-to-dust ratio over a wide range of stellar masses (from 10^7^ to 10^11^M_{sun}_) for both dwarfs and spirals. Highly HI-deficient Virgo dwarf galaxies are mostly characterised by quenched star formation activity and lower dust fractions giving hints for dust stripping in cluster dwarfs. However, to explain the large dust-to-gas mass ratios observed in these systems, we find that the fraction of dust removed has to be less than that of the HI component. The cluster environment seems to mostly affect the gas component and star formation activity of the dwarfs. Since the Virgo star-forming dwarfs are likely to be crossing the cluster for the first time, a longer timescale might be necessary to strip the more centrally concentrated dust distribution.
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Search Results
- ID:
- ivo://CDS.VizieR/J/A+A/597/A130
- Title:
- HI and 250um images of the Virgo cirrus
- Short Name:
- J/A+A/597/A130
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We study the correlation between far-infrared/submm dust emission and atomic gas column density in order to derive the properties of the high Galactic latitude, low density, Milky Way cirrus in the foreground of the Virgo cluster of galaxies. Dust emission maps from 60 to 850um are obtained from SPIRE observations carried out within the Herschel Virgo Cluster Survey, complemented by IRAS-IRIS and Planck-HFI maps. Data from the Arecibo legacy Fast ALFA Survey is used to derive atomic gas column densities for two broad velocity components, low and intermediate velocity clouds. Dust emissivities are derived for each gas component and each far-infrared/submm band. For the low velocity clouds, we measure an average emissivity {epsilon]_{nu}^LVC=(0.79+/-0.08)*10^-20^MJy.cm^2^/sr at 250um. After fitting a modified blackbody to the available bands, we estimated a dust absorption cross-section {tau}_{nu}^LVC/N_HI_=(0.49+/-0.13)*10^-25cm^2^/H at 250um (with dust temperature T=20.4+/-1.5K and spectral index {beta}=1.53+/-0.17). The results are in excellent agreement with those obtained by Planck over a much larger coverage of the high Galactic latitude cirrus (50% of the sky vs 0.2% in our work). For dust associated with intermediate velocity gas, we confirm earlier Planck results and find a higher temperature and lower emissivity and cross-section. After subtracting the modelled components, we find regions at scales smaller than 20' where the residuals deviate significantly from the average, cosmic-infrared-background dominated, scatter. These large residuals are most likely due to local variations in the cirrus dust properties (and/or the dust/atomic-gas correlation) or to high-latitude molecular clouds with average N_H2_<~10^20^cm^-2^. We find no conclusive evidence for intracluster dust emission in Virgo.
- ID:
- ivo://CDS.VizieR/J/A+A/565/A25
- Title:
- Hickson compact groups Herschel observations
- Short Name:
- J/A+A/565/A25
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present a Herschel far-infrared and sub-millimetre (sub-mm) study of a sample of 120 galaxies in 28 Hickson compact groups (HCGs). Fitting their UV to sub-mm spectral energy distributions with the model of da Cunha et al. (2008MNRAS.388.1595C), we accurately estimate the dust masses, luminosities, and temperatures of the individual galaxies.
- ID:
- ivo://CDS.VizieR/VII/85A
- Title:
- Hickson Compact Groups of Galaxies
- Short Name:
- VII/85A
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The catalog 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 and satisfies an isolation criterion. The catalog includes running numbers, equatorial coordinates, group types according to the two brightest members, number of galaxies in the group, angular diameters of the smallest circles containing the geometric centers of all group members, total magnitudes (red) of those galaxies counted as group members, estimated red magnitudes of the brightest galaxies in the groups, corrected redshifts of the brightest galaxies, and other designations of the groups.
- 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.
