- ID:
- ivo://CDS.VizieR/J/A+A/418/445
- Title:
- FCOS Ultra Compact Dwarf galaxies radial vel.
- Short Name:
- J/A+A/418/445
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The relation between the Ultra Compact Dwarf galaxies (hereafter UCDs) recently discovered in the Fornax cluster (Drinkwater et al., 2003Natur.423..519D; Mieske et al., 2002, Cat. <J/A+A/383/823>) and the brightest globular clusters associated with the central galaxy NGC 1399 has been investigated in the spectroscopic Fornax Compact Object Survey FCOS. FCOS was carried out with the 2.5m du Pont telescope at Las Campanas, in the three nights of 2002/12/04 to 2002/12/06. Mieske et al. (2002, Cat. <J/A+A/383/823>) deals with the first part FCOS-1, this paper deals with the larger FCOS-2. The spectral resolution of FCOS was approx. 4{AA}. In the FCOS, 280 unresolved objects with 0<(V-I)<1.5mag in the magnitude space covering UCDs and bright globular clusters (18<V<21mag) were observed spectroscopically, among them 185 in FCOS-2. In the entire FCOS-sample there are five already known UCDs and 54 new Fornax members, 12 from FCOS-1 and 42 from FCOS-2.
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Search Results
- ID:
- ivo://CDS.VizieR/J/A+A/527/A134
- Title:
- Fe abundances for 28 XMM galaxy clusters
- Short Name:
- J/A+A/527/A134
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The abundances of Fe in the intracluster medium of nearby (z<0.08) clusters were measured up to 0.3~0.5r_180_. We analyzed 28 clusters of galaxies observed with XMM-Newton. We derived Fe abundances from the flux ratios of Fe lines to the continuum within an energy range of 3.5-6keV to minimize and evaluate systematic uncertainties.
- ID:
- ivo://CDS.VizieR/J/AJ/108/1
- Title:
- Flatness of clusters of galaxies
- Short Name:
- J/AJ/108/1
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We examine relations between shape, richness, and velocity dispersion for a sample of 350 clusters of galaxies of all morphologies, including those with visible substructure. For our sample the apparent shape of clusters is correlated with velocity dispersion and Abell (1958ApJS....3..211A) richness in the sense that poor, low dispersion clusters are flatter in the mean than their richer, higher dispersion counterparts. These characteristics are also exhibited by the X-ray emitting gas. There are virtually no highly flattened clusters having high richness or high velocity dispersions in the sample. We find that the variation of richness and velocity dispersion with apparent shape is too steep to be assigned to projection effects, and conclude rich, high dispersion clusters are intrinsically more nearly spherical than poorer clusters and that two-body relaxation is probably not an effective anisotropy damping mechanism in Abell clusters.
- ID:
- ivo://CDS.VizieR/J/A+A/566/A1
- Title:
- Flux- and volume-limited groups for SDSS galaxies
- Short Name:
- J/A+A/566/A1
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We provide flux-limited and volume-limited galaxy group and cluster catalogues, based on the spectroscopic sample of the SDSS data release 10 galaxies. We used a modified friends-of-friends (FoF) method with a variable linking length in the transverse and radial directions to identify as many realistic groups as possible. The flux-limited catalogue incorporates galaxies down to m_r_=17.77mag. It includes 588193 galaxies and 82458 groups. The volume-limited catalogues are complete for absolute magnitudes down to M_r_= -18.0, -18.5, -19.0, -19.5, -20.0, -20.5, and -21.0; the completeness is achieved within different spatial volumes, respectively. Our analysis shows that flux-limited and volume-limited group samples are well compatible to each other, especially for the larger groups/clusters. Dynamical mass estimates, based on radial velocity dispersions and group extent in the sky, are added to the extracted groups. The catalogues can also be accessed via http://cosmodb.to.ee.
- ID:
- ivo://CDS.VizieR/J/ApJ/825/72
- Title:
- Follow-up study of gal. & AGNs in z>1 clusters
- Short Name:
- J/ApJ/825/72
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present a detailed, multi-wavelength study of star formation (SF) and active galactic nucleus (AGN) activity in 11 near-infrared (IR) selected, spectroscopically confirmed massive (>~10^14^M_{sun}_) galaxy clusters at 1<z<1.75. Using new deep Herschel/PACS imaging, we characterize the optical to far-IR spectral energy distributions (SEDs) for IR-luminous cluster galaxies, finding that they can, on average, be well described by field galaxy templates. Identification and decomposition of AGNs through SED fittings allows us to include the contribution to cluster SF from AGN host galaxies. We quantify the star-forming fraction, dust-obscured SF rates (SFRs) and specific SFRs for cluster galaxies as a function of cluster-centric radius and redshift. In good agreement with previous studies, we find that SF in cluster galaxies at z>~1.4 is largely consistent with field galaxies at similar epochs, indicating an era before significant quenching in the cluster cores (r<0.5Mpc). This is followed by a transition to lower SF activity as environmental quenching dominates by z~1. Enhanced SFRs are found in lower mass (10.1<logM_*_/M_{sun}_<10.8) cluster galaxies. We find significant variation in SF from cluster to cluster within our uniformly selected sample, indicating that caution should be taken when evaluating individual clusters. We examine AGNs in clusters from z=0.5-2, finding an excess AGN fraction at z>~1, suggesting environmental triggering of AGNs during this epoch. We argue that our results --a transition from field-like to quenched SF, enhanced SF in lower mass galaxies in the cluster cores, and excess AGNs-- are consistent with a co-evolution between SF and AGNs in clusters and an increased merger rate in massive halos at high redshift.
- ID:
- ivo://CDS.VizieR/J/MNRAS/427/2047
- Title:
- Formation of cD Galaxies and their Clusters
- Short Name:
- J/MNRAS/427/2047
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- In order to study the mechanism of formation of cD galaxies we search for possible dependencies between the K-band luminosity of cDs and the parameters of their host clusters which we select to have a dominant cD galaxy, corresponding to a cluster morphology of Bautz-Morgan (BM) type I. As a comparison sample we use cD galaxies in clusters where they are not dominant, which we define here as non-BM I (NBMI) type clusters. We find that for 71 BM I clusters the absolute K-band luminosity of cDs depends on the cluster richness, but less strongly on the cluster velocity dispersion. Meanwhile, for 35 NBMI clusters the correlation between cD luminosity and cluster richness is weaker, and is absent between cD luminosity and velocity dispersion. In addition, we find that the luminosity of the cD galaxy hosted in BM I clusters tends to increase with the cD's peculiar velocity with respect to the cluster mean velocity. In contrast, for NBMI clusters the cD luminosity decreases with increasing peculiar velocity. Also, the X-ray luminosity of BM I clusters depends on the cluster velocity dispersion, while in NBMI clusters such a correlation is absent. These findings favour the cannibalism scenario for the formation of cD galaxies. We suggest that cDs in clusters of BM I type were formed and evolved preferentially in one and the same cluster. In contrast, cDs in NBMI type clusters were either originally formed in clusters that later merged with groups or clusters to form the current cluster, or are now in the process of merging.
- ID:
- ivo://CDS.VizieR/J/A+A/296/319
- Title:
- Fornax cluster early-type galaxies
- Short Name:
- J/A+A/296/319
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- (no description available)
- ID:
- ivo://CDS.VizieR/J/other/PASA/38.20
- Title:
- Fornax cluster magnetic fields
- Short Name:
- J/other/PASA/38.
- Date:
- 17 Jan 2022 00:49:54
- Publisher:
- CDS
- Description:
- We present the first Faraday rotation measure (RM) grid study of an individual low-mass cluster - the Fornax cluster - which is presently undergoing a series of mergers. Exploiting commissioning data for the POlarisation Sky Survey of the Universe's Magnetism (POSSUM) covering a ~34 square degree sky area using the Australian Square Kilometre Array Pathfinder (ASKAP), we achieve an RM grid density of ~25 RMs per square degree from a 280MHz band centred at 887MHz, which is similar to expectations for forthcoming GHz-frequency 3-steradian sky surveys. These data allow us to probe the extended magnetoionic structure of the cluster and its surroundings in unprecedented detail. We find that the scatter in the Faraday RM of confirmed background sources is increased by 16.8+/-2.4rad/m^2^ within 1 degree (360kpc) projected distance to the cluster centre, which is 2-4 times larger than the spatial extent of the presently-detectable X-ray-emitting intracluster medium (ICM). The mass of the Faraday-active plasma is larger than that of the X-ray-emitting ICM, and exists in a density regime that broadly matches expectations for moderately-dense components of the Warm-Hot Intergalactic Medium. We argue that forthcoming RM grids from both targeted and survey observations may be a singular probe of cosmic plasma in this regime. The morphology of the global Faraday depth enhancement is not uniform and isotropic, but rather exhibits the classic morphology of an astrophysical bow shock on the southwest side of the main Fornax cluster, and an extended, swept-back wake on the northeastern side. Our favoured explanation for these phenomena is an ongoing merger between the main cluster and a sub-cluster to the southwest. The shock's Mach angle and stand-o distance lead to a self-consistent transonic merger speed with Mach 1.06. The region hosting the Faraday depth enhancement also appears to show a decrement in both total and polarised radio emission compared to the broader field. We evaluate cosmic variance and free-free absorption by a pervasive cold dense gas surrounding NGC 1399 as possible causes, but find both explanations unsatisfactory, warranting further observations. Generally, our study illustrates the scientific returns that can be expected from all-sky grids of discrete sources generated by forthcoming all-sky radio surveys.
- ID:
- ivo://CDS.VizieR/J/A+A/476/59
- Title:
- Fornax Cluster Spectroscopic Survey 2MASS galaxies
- Short Name:
- J/A+A/476/59
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The Fornax Cluster Spectroscopic Survey (FCSS) is an all-object survey of a region around the Fornax Cluster of galaxies undertaken using the 2dF multi-object spectrograph on the Anglo-Australian Telescope. Its aim was to obtain spectra for a complete sample of all objects with 16.5<b_j_<19.7 irrespective of their morphology (i.e. including `stars', `galaxies' and `merged' images). We explore the extent to which (nearby) cluster galaxies are present in 2MASS. We consider the reasons for the omission of 2MASS galaxies from the FCSS and vice versa. We consider the intersection (2.9 square degrees on the sky) of our data set with the infra-red 2 Micron All-Sky Survey (2MASS), using both the 2MASS Extended Source Catalogue (XSC) and the Point Source Catalogue (PSC). We match all the XSC objects to FCSS counterparts by position and also extract a sample of galaxies, selected by their FCSS redshifts, from the PSC. We confirm that all 114 XSC objects in the overlap sample are galaxies, on the basis of their FCSS velocities. A total of 23 Fornax Cluster galaxies appear in the matched data, while, as expected, the remainder of the sample lie at redshifts out to z=0.2 (the spectra show that 61% are early type galaxies, 18% are intermediate types and 21% are strongly star forming). The PSC sample turns out to contain twice as many galaxies as does the XSC. However, only one of these 225 galaxies is a (dwarf) cluster member. On the other hand, galaxies which are unresolved in the 2MASS data (though almost all are resolved in the optical) amount to 71% of the non-cluster galaxies with 2MASS detections and have redshifts out to z=0.32.
- ID:
- ivo://CDS.VizieR/J/A+A/608/A142
- Title:
- Fornax Deep Survey with VST. III. LSB galaxies
- Short Name:
- J/A+A/608/A142
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Studies of low surface brightness (LSB) galaxies in nearby clusters have revealed a sub-population of extremely diffuse galaxies with central surface brightness of {mu}_0,g'_>24mag/arcsec^2^, total luminosity M_g'_ fainter than -16mag and effective radius between 1.5kpc<R_e_<10kpc. The origin of these ultra diffuse galaxies (UDGs) is still unclear, although several theories have been suggested. As the UDGs overlap with the dwarf-sized galaxies in their luminosities, it is important to compare their properties in the same environment. If a continuum is found between the properties of UDGs and the rest of the LSB population, it would be consistent with the idea that they have a common origin. Our aim is to exploit the deep g', r' and i'-band images of the Fornax Deep Survey (FDS), in order to identify LSB galaxies in an area of 4deg^2^ in the center of the Fornax cluster. The identified galaxies are divided into UDGs and dwarf-sized LSB galaxies, and their properties are compared. We identified visually all extended structures having r'-band central surface brightness of {mu}_0,r'_>23mag/arcsec^2^. We classified the objects based on their appearance into galaxies and tidal structures, and perform 2D Sersic model fitting with GALFIT to measure the properties of those classified as galaxies. We analyzed their radial distribution and orientations with respect of the cluster center, and with respect to the other galaxies in our sample. We also studied their colors and compare the LSB galaxies in Fornax with those in other environments. Our final sample complete in the parameter space of the previously known UDGs, consists of 205 galaxies of which 196 are LSB dwarfs (with R_e_<1.5kpc) and nine are UDGs (R_e_>1.5kpc). We show that the UDGs have (1) g'-r' colors similar to those of LSB dwarfs of the same luminosity; (2) the largest UDGs (R_e_>3kpc) in our sample appear different from the other LSB galaxies, in that they are significantly more elongated and extended; whereas (3) the smaller UDGs differ from the LSB dwarfs only by having slightly larger effective radii; (4) we do not find clear differences between the structural parameters of the UDGs in our sample and those of UDGs in other galaxy environments; (5) we find that the dwarf LSB galaxies in our sample are less concentrated in the cluster center than the galaxies with higher surface brightness, and that their number density drops within 180 kpc from the cluster center. We also compare the LSB dwarfs in Fornax with the LSB dwarfs in the Centaurus group, where data of similar quality to ours is available. (6) We find the smallest LSB dwarfs to have similar colors, sizes and Sersic profiles regardless of their environment. However, in the Centaurus group the colors become bluer with increasing galaxy magnitudes, an effect which is probably due to smaller mass and hence weaker environmental influence of the Centaurus group. Our findings are consistent with the small UDGs forming the tail of a continuous distribution of less extended LSB galaxies. However, the elongated and distorted shapes of the large UDGs could imply that they are tidally disturbed galaxies. Due to limitations of the automatic detection methods and uncertainty in the classification the objects, it is yet unclear what is the total contribution of the tidally disrupted galaxies in the UDG population.
