- 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.
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Search Results
- 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.
- ID:
- ivo://CDS.VizieR/J/A+A/620/A165
- Title:
- Fornax Deep Survey with VST. IV. dwarf galaxies
- Short Name:
- J/A+A/620/A165
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The Fornax Deep Survey (FDS), an imaging survey in the u', g', r', and i'-bands, has a supreme resolution and image depth compared to the previous spatially complete Fornax Cluster Catalog (FCC). Our new data allows us to study the galaxies down to r'- band magnitude mr~=21mag (Mr'~=-10.5mag), which opens a new parameter regime to investigate the evolution of dwarf galaxies in the cluster environment. After the Virgo cluster, Fornax is the second nearest galaxy cluster to us, and with its different mass and evolutionary state, it provides a valuable comparison that makes it possible to understand the various evolutionary effects on galaxies and galaxy clusters. These data provide an important legacy dataset to study the Fornax cluster. We aim to present the Fornax Deep Survey (FDS) dwarf galaxy catalog, focusing on explaining the data reduction and calibrations, assessing the quality of the data, and describing the methods used for defining the cluster memberships and first order morphological classifications for the catalog objects. We also describe the main scientific questions that will be addressed based on the catalog. This catalog will also be invaluable for future follow-up studies of the Fornax cluster dwarf galaxies. As a first step we used the SExtractor fine-tuned for dwarf galaxy detection, to find galaxies from the FDS data, covering a 26deg^2^ area of the main cluster up to its virial radius, and the area around the Fornax A substructure. We made 2D-decompositions of the identified galaxies using GALFIT, measure the aperture colors, and the basic morphological parameters like concentration and residual flux fraction. We used color-magnitude, luminosity-radius and luminosity-concentration relations to separate the cluster galaxies from the background galaxies. We then divided the cluster galaxies into early- and late-type galaxies according to their morphology and gave first order morphological classifications using a combination of visual and parametric classifications. Our final catalog includes 14,095 galaxies. We classify 590 galaxies as being likely Fornax cluster galaxies, of which 564 are dwarfs (Mr'>-18.5mag) consisting our Fornax dwarf catalog. Of the cluster dwarfs we classify 470 as early-types, and 94 as late-type galaxies. Our final catalog reaches its 50% completeness limit at magnitude Mr'=-10.5mag and surface brightness <{mu}_e,r'_=26mag/arcsec^2^, which is approximately three magnitudes deeper than the FCC. Based on previous works and comparison with a spectroscopically confirmed subsample, we estimate that our final Fornax dwarf galaxy catalog has <~10% contamination from the background objects.
- ID:
- ivo://CDS.VizieR/J/A+A/623/A1
- Title:
- Fornax Deep Survey with VST. V. Isophote fit
- Short Name:
- J/A+A/623/A1
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- This paper is based on the multi-band (ugri) Fornax Deep Survey (FDS) with the VLT Survey Telescope (VST). We study bright early-type galaxies (m_B_<15mag) in the 9 square degrees around the core of the Fornax cluster, which covers the virial radius (R_vir~0.7Mpc). The main goal of the present work is to provide an analysis of the light distribution for all galaxies out to unprecedented limits (in radius and surface brightness) and to release the main products resulting from this analysis in all FDS bands. We give an initial comprehensive view of the galaxy structure and evolution as a function of the cluster environment. From the isophote fit, we derived the azimuthally averaged surface brightness profiles, the position angle, and ellipticity profiles as a function of the semi-major axis. In each band, we derived the total magnitudes, effective radii, integrated colours, and stellar mass-to-light ratios. The long integration times, the arcsec-level angular resolution of OmegaCam@VST, and the large covered area of FDS allow us to map the light and colour distributions out to large galactocentric distances (up to about 10^-15^Re) and surface brightness levels beyond mu_r_=27mag/arcsec^2^ (mu_B_>28mag/arcsec^2^). Therefore, the new FDS data allow us to explore in great detail the morphology and structure of cluster galaxies out to the region of the stellar halo. The analysis presented in this paper allows us to study how the structure of galaxies and the stellar population content vary with the distance from the cluster centre. In addition to the intra-cluster features detected in previous FDS works, we found a new faint filament between FCC 143 and FCC 147, suggesting an ongoing interaction. The observations suggest that the Fornax cluster is not completely relaxed inside the virial radius. The bulk of the gravitational interactions between galaxies happens in the W-NW core region of the cluster, where most of the bright early-type galaxies are located and where the intra-cluster baryons (diffuse light and globular clusters) are found. We suggest that the W-NW sub-clump of galaxies results from an infalling group onto the cluster, which has modified the structure of the galaxy outskirts (making asymmetric stellar halos) and has produced the intra-cluster baryons (ICL and GCs), concentrated in this region of the cluster.
- ID:
- ivo://CDS.VizieR/J/A+A/647/A100
- Title:
- Fornax Deep Survey with VST. XI.
- Short Name:
- J/A+A/647/A100
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Galaxies either live in a cluster, a group, or in a field environment. In the hierarchical framework, the group environment bridges the field to the cluster environment, as field galaxies form groups before aggregating into clusters. In principle, environmental mechanisms, such as galaxy-galaxy interactions, can be more efficient in groups than in clusters due to lower velocity dispersion, which lead to changes in the properties of galaxies. This change in properties for group galaxies before entering the cluster environment is known as preprocessing. Whilst cluster and field galaxies are well studied, the extent to which galaxies become preprocessed in the group environment is unclear. We investigate the structural properties of cluster and group galaxies by studying the Fornax main cluster and the infalling Fornax A group, exploring the effects of galaxy preprocessing in this showcase example. Additionally, we compare the structural complexity of Fornax galaxies to those in the Virgo cluster and in the field. Our sample consists of 582 galaxies from the Fornax main cluster and Fornax A group. We quantified the light distributions of each galaxy based on a combination of aperture photometry, Sersic+PSF (point spread function) and multi-component decompositions, and non-parametric measures of morphology. From these analyses, we derived the galaxy colours, structural parameters, non-parametric morphological indices (Concentration C; Asymmetry A, Clumpiness S; Gini G; second order moment of light M_20_), and structural complexity based on multi-component decompositions. These quantities were then compared between the Fornax main cluster and Fornax A group. The structural complexity of Fornax galaxies were also compared to those in Virgo and in the field. We find significant (Kolmogorov-Smirnov test p-value <alpha=0.05) differences in the distributions of quantities derived from Sersic profiles (g'-r', r'-i', Re, and {bar}{mu}_e,r'_), and non-parametric indices (A and S) between the Fornax main cluster and Fornax A group. Fornax A group galaxies are typically bluer, smaller, brighter, and more asymmetric and clumpy. Moreover, we find significant cluster-centric trends with r'-i', Re, and {bar}{mu}_e,r'_, as well as A, S, G, and M_20_ for galaxies in the Fornax main cluster. This implies that galaxies falling towards the centre of the Fornax main cluster become fainter, more extended, and generally smoother in their light distribution. Conversely, we do not find significant group-centric trends for Fornax A group galaxies. We find the structural complexity of galaxies (in terms of the number of components required to fit a galaxy) to increase as a function of the absolute r'-band magnitude (and stellar mass), with the largest change occurring between -14mag<~Mr'<~-19,mag (7.5<~log_10_(M*/M_{sun}_)~=9.7). This same trend was found in galaxy samples from the Virgo cluster and in the field, which suggests that the formation or maintenance of morphological structures (e.g. bulges, bar) are largely due to the stellar mass of the galaxies, rather than the environment they reside in.
- ID:
- ivo://CDS.VizieR/J/A+A/637/A62
- Title:
- Fornax3D. Planetary nebulae automated detection
- Short Name:
- J/A+A/637/A62
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Extragalactic Planetary Nebulae (PNe) are detectable via relatively strong nebulous [OIII] emission, acting as direct probes into the local stellar population. Due to an apparently universal, invariant magnitude cut-off, PNe are also considered to be a remarkable standard candle for distance estimation. Through detecting PNe within the galaxies, we aim to connect the relative abundances of PNe to the properties of their host galaxy stellar population. By removing the stellar background components from FCC 167 and FCC 219, we aim to produce PN Luminosity Functions (PNLF) of those galaxies, and therefore also estimate the distance modulus to those two systems. Finally, we test the reliability and robustness of the our novel detection and analysis method. It detects the presence of unresolved point sources via their [OIII] 5007{AA} emission, within regions previously unexplored. We model the [OIII] emissions in both the spatial and spectral dimensions together, as afforded to us by the Multi Unit Spectroscopic Explorer (MUSE) and drawing on data gathered as part of the Fornax3D survey. For each source, we inspect the properties of the nebular emission lines present to remove other sources, that could hinder the safe construction of the PNLF, such as supernova remnants and HII regions. As a further step, we characterise any potential limitations and draw conclusions about the reliability of our modelling approach via a set of simulations. Through the application of this novel detection and modelling approach to IFU observations, we report for both galaxies: distance estimates, luminosity specific PNe frequency values. Furthermore, we include an overview into source contamination, galaxy differences and how they may affect the PNe populations in the dense stellar environments.
4807. Fornax3D PNe Catalogue
- ID:
- ivo://CDS.VizieR/J/A+A/653/A167
- Title:
- Fornax3D PNe Catalogue
- Short Name:
- J/A+A/653/A167
- Date:
- 22 Feb 2022
- Publisher:
- CDS
- Description:
- Extragalactic planetary nebulae (PNe) offer a way to determine the distance to their host galaxies thanks to the nearly universal shape of the luminosity function (PNLF). Accurate PNe distance measurements rely on obtaining well- sampled PNLFs and the number of observed PNe scales with the encompassed stellar mass. This means either disposing of wide-field observations or on focusing on the bright central regions of galaxies. In this work we take this second approach and conduct a census of the PNe population in the central regions of galaxies in the Fornax cluster, using VLT/MUSE data for the early- type galaxies observed over the course of the Fornax3D survey. Using such integral-field spectroscopic observations to carefully separate the nebular emission from the stellar continuum, we isolate [OIII] 5007{AA} sources of interest, filter out unresolved impostor sources or kinematic outliers, and present a catalogue of 1350 unique PNe sources across 21 early- type galaxies, which includes their positions, [OIII} 5007{AA} line magnitudes and line-of-sight velocities. Using the PNe catalogued within each galaxy, we present independently-derived distance estimates based on the fit to the entire observed PNLF observed while carefully accounting for the PNe detection incompleteness. With these individual measurements we arrive at an average distance to the Fornax cluster itself of 19.86+/-0.32Mpc ({mu}_PNLF_=31.49+/-0.04mag). Our PNLF distance measurements agree well with previous distances based on surface brightness fluctuations, finding no significant systematic offsets between the two methods as otherwise reported in previous studies.
- ID:
- ivo://CDS.VizieR/J/A+A/637/A26
- Title:
- Fornax 3D project. Globular clusters
- Short Name:
- J/A+A/637/A26
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Globular clusters (GCs) are found ubiquitously in massive galaxies and due to their old ages, they are regarded as fossil records of galaxy evolution. Spectroscopic studies of GC systems are often limited to the outskirts of galaxies, where GCs stand out against the galaxy background and serve as bright tracers of galaxy assembly. In this work we use the capabilities of the Multi Unit Explorer Spectrograph (MUSE) to extract a spectroscopic sample of 722 GCs in the inner regions (<3Reff) of 32 galaxies in the Fornax cluster. These galaxies were observed as part of the Fornax 3D project, a MUSE survey that targets early and late-type galaxies within the virial radius of Fornax. After accounting for the galaxy background in the GC spectra, we extracted line-of-sight velocities and determined metallicities of a subsample of 238 GCs. We found signatures of rotation within GC systems and comparing the GC kinematics and that of the stellar body shows that the angular momentum of the GC system reflects that of the stars, confirming the usefulness of GCs as kinematic tracers. While the red GCs prove to closely follow the metallicity profile of the host galaxy, the blue GCs show a large spread of metallicities but are generally more metal -poor than the host.
- ID:
- ivo://CDS.VizieR/J/A+A/585/A86
- Title:
- Fornax dSph H4 globular cluster stars
- Short Name:
- J/A+A/585/A86
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The globular cluster H4, located in the center of the Fornax dwarf spheroidal galaxy, is crucial for understanding the formation and chemical evolution of star clusters in low-mass galactic environments. H4 is peculiar because the cluster is significantly more metal-rich than the galaxy's other clusters, is located near the galaxy center, and may also be the youngest cluster in the galaxy. In this study, we present detailed chemical abundances derived from high-resolution (R~28000) spectroscopy of an isolated H4 member star for comparison with a sample of 22 nearby Fornax field stars. We find the H4 member to be depleted in the alpha-elements Si, Ca, and Ti with [Si/Fe]=-0.35+/-0.34, [Ca/Fe]=+0.05+/-0.08, and [Ti/Fe]=-0.27+/-0.23, resulting in an average [{alpha}/Fe]=-0.19+/-0.14. If this result is representative of the average cluster properties, H4 is the only known system with a low [{alpha}/Fe] ratio and a moderately low metallicity embedded in an intact birth environment. For the field stars we find a clear sequence, seen as an early depletion in [{alpha}/Fe] at low metallicities, in good agreement with previous measurements. H4 falls on top of the observed field star [{alpha}/Fe] sequence and clearly disagrees with the properties of Milky Way halo stars. We therefore conclude that within a galaxy, the chemical enrichment of globular clusters may be closely linked to the enrichment pattern of the field star population. The low [{alpha}/Fe] ratios of H4 and similar metallicity field stars in Fornax give evidence that slow chemical enrichment environments, such as dwarf galaxies, may be the original hosts of alpha-depleted clusters in the halos of the Milky Way and M31.
- ID:
- ivo://nasa.heasarc/fornaxxmm
- Title:
- Fornax Dwarf Galaxy XMM-Newton X-Ray Point Source Catalog
- Short Name:
- FORNAXXMM
- Date:
- 27 Sep 2024
- Publisher:
- NASA/GSFC HEASARC
- Description:
- This table contains some of the results of a deep archive XMM-Newton observation of the Fornax spheroidal galaxy that the authors analyzed with the aim of fully characterizing the X-ray source population (in most of the cases likely to be background active galactic nuclei) detected towards the target. A cross-correlation with the available databases allowed them to find a source that may be associated with a variable star belonging to the galaxy. The authors also searched for X-ray sources in the vicinity of the Fornax globular clusters GC 3 and GC 4 and found two sources probably associated with the respective clusters. The deep X-ray observation was also suitable for the search for the intermediate-mass black hole (of mass ~ 10<sup>4</sup> solar masses) expected to be hosted in the center of the galaxy. In the case of Fornax, this search is extremely difficult since the galaxy centroid of gravity is poorly constrained because of the large asymmetry observed in the optical surface brightness. Since the authors cannot firmly establish the existence of an X-ray counterpart of the putative black hole, they put constraints only on the accretion parameters. In particular, they found that the corresponding upper limit on the accretion efficiency, with respect to the Eddington luminosity, is as low as a few 10<sup>-5</sup>. This table was created by the HEASARC in February 2013 based on an electronic version of Table 1 from the reference paper which was obtained from the A&A web site. This is a service provided by NASA HEASARC .