- ID:
- ivo://CDS.VizieR/J/A+AS/129/455
- Title:
- Dwarf galaxy candidates around interacting galaxies
- Short Name:
- J/A+AS/129/455
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present results from the imaging of a sample of 12 interacting galaxies for which we have catalogued all potential dwarf systems in the vicinity of these strongly interacting galaxies. After careful cleaning of the images and applying a restrictive S/N criterion we have identified, measured and catalogued all possible extended objects in each field. On the frames, covering 11.4x10.5arcmins, on the order of 100 non-stellar, faint, extended objects were found around each interacting galaxy. The vast majority (>98%) of these objects had not been previously identified. The number of expected objects in the magnitude range R=18-19.5 exceeds the expected count of background galaxies. This supports the possibility that a density enhancement of extended objects around some interacting galaxies results from the addition of a locally formed dwarf galaxy population.
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Search Results
- ID:
- ivo://CDS.VizieR/J/MNRAS/435/1928
- Title:
- Dwarf galaxy planes in Local Group
- Short Name:
- J/MNRAS/435/1928
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Both major galaxies in the Local Group (LG) are surrounded by thin planes of mostly co-orbiting satellite galaxies, the vast polar structure (VPOS) around the Milky Way (MW) and the Great Plane of Andromeda (GPoA) around M31. We summarize the current knowledge concerning these structures and compare their relative orientations by re-determining their properties in a common coordinate system. The existence of similar, coherent structures around both major LG galaxies motivates an investigation of the distribution of the more distant non-satellite galaxies in the LG. This results in the discovery of two planes (diameters of 1-2Mpc) which contain almost all nearby non-satellite galaxies. The two LG planes are surprisingly symmetric. They are inclined by only 20{deg} relative to the galactic disc of M31, are similarly thin (heights of {approx}60kpc) and have near-to-identical offsets from the MW and from M31. They are inclined relative to each other by 35{deg}. Comparing the plane orientations with each other and with additional features reveals indications for an intimate connection between the VPOS and the GPoA. They are both polar with respect to the MW, have similar orbital directions and are inclined by about 45{deg}+/-7{deg} relative to each other. The Magellanic Stream approximately aligns with the VPOS and the GPoA, but also shares its projected position and line-of-sight velocity trend with a part of the dominating structure of non-satellite dwarf galaxies. In addition, the recent proper motion measurement of M31 indicates a prograde orbit of the MW-M31 system, the VPOS and the GPoA. The alignment with other features such as the Supergalactic Plane and the overdensity in hypervelocity stars are discussed as well. We end with a short summary of the currently proposed scenarios trying to explain the LG galaxy structures as either originating from cosmological structures or from tidal debris of a past galaxy encounter. We emphasize that there currently exists no full detailed model which satisfactorily explains the existence of the thin symmetric LG planes.
- ID:
- ivo://CDS.VizieR/J/A+A/645/A92
- Title:
- Dwarf spheroidal galaxies in CenA group
- Short Name:
- J/A+A/645/A92
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Dwarf spheroidal galaxies (dSphs) have been extensively investigated in the Local Group, but their low luminosity and surface brightness make similar work in more distant galaxy groups challenging. Modern instrumentation unlocks the possibility of scrutinizing these faint systems in other environments, expanding the parameter space of group properties. We use MUSE spectroscopy to study the properties of 14 known or suspected dSph satellites of Cen A. Twelve targets are confirmed to be group members based on their radial velocities. Two targets are background galaxies at ~50Mpc: KK 198 is a face-on spiral galaxy, and dw1315-45 is an ultra-diffuse galaxy with an effective radius of ~2300pc. The 12 confirmed dSph members of the Cen A group have old and metal-poor stellar populations and follow the stellar metallicity-luminosity relation defined by the dwarf galaxies in the Local Group. In the three brightest dwarf galaxies (KK 197, KKs 55, and KKs 58), we identify globular clusters, as well as a planetary nebula in KK197, although its association with this galaxy and/or the extended halo of Cen A is uncertain. Using four discrete tracers, we measure the velocity dispersion and dynamical mass of KK197. This dSph appears dark matter dominated and lies on the radial acceleration relation of star-forming galaxies within the uncertainties. It also is consistent with predictions stemming from modified Newtonian dynamics (MOND). Surprisingly, in the dwarf KK203 we find an extended H ring. Careful examination of Hubble Space Telescope photometry reveals a very low level of star formation at ages between 30-300Myr. The H{alpha} emission is most likely linked to a ~40Myr old supernova remnant, although other possibilities for its origin cannot be entirely ruled out.
- ID:
- ivo://CDS.VizieR/J/ApJ/771/85
- Title:
- Dynamical masses of z~2 quiescent galaxies
- Short Name:
- J/ApJ/771/85
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Using stellar kinematics measurements, we investigate the growth of massive, quiescent galaxies from z~2 to today. We present X-Shooter spectra from the UV to NIR and dynamical mass measurements of five quiescent massive (>10^11^M_{sun}_) galaxies at z~2. This triples the sample of z>1.5 galaxies with well-constrained ({delta}{sigma}<100km/s) velocity dispersion measurements. From spectral population synthesis modeling we find that these galaxies have stellar ages that range from 0.5 to 2Gyr, with no signs of ongoing star formation. We measure velocity dispersions (290-450km/s) from stellar absorption lines and find that they are 1.6-2.1 times higher than those of galaxies in the Sloan Digital Sky Survey at the same mass. Sizes are measured using GALFIT from Hubble Space Telescope Wide Field Camera 3 H_160_ and UDS K-band images. The dynamical masses correspond well to the spectral energy distribution based stellar masses, with dynamical masses that are ~15% higher.
- ID:
- ivo://CDS.VizieR/J/MNRAS/363/769
- Title:
- Dynamical modelling of 4 early-type galaxies
- Short Name:
- J/MNRAS/363/769
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We analyse long-slit spectra of four early-type galaxies which extend from ~1 to 3 effective radii: IC 1459; IC 3370; NGC 3379 and NGC 4105. We have extracted the full line-of-sight velocity distribution (in the case of NGC 3379 we also used data from the literature), which we model using the two-integral approach. Using two-integral modelling, we find no strong evidence for dark haloes, but the fits suggest that three-integral modelling is necessary. We also find that the inferred constant mass-to-light ratio in all the four cases is typical for early-type galaxies. Finally, we also discuss the constraints on the mass-to-light ratio, which can be obtained using X-ray haloes in the case of IC 1459, NGC 3379 and NGC 4105, and compare the estimated values with the predictions from the dynamical modelling.
- ID:
- ivo://CDS.VizieR/J/MNRAS/370/1223
- Title:
- Dynamical properties of 15 nearby galaxy groups
- Short Name:
- J/MNRAS/370/1223
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Here, we present an investigation of the properties of 15 nearby galaxy groups and their constituent galaxies. The groups are selected from the Group Evolution Multiwavelength Study (GEMS) and all have X-ray as well as wide-field neutral hydrogen (HI) observations. Group membership is determined using a friends-of-friends algorithm on the positions and velocities from the 6-degree Field Galaxy Survey and NASA/IPAC Extragalactic Database. For each group we derive their physical properties using this membership, including: velocity dispersions (sigma_v_), virial masses (M_V_), total K-band luminosities [L_K_(Tot)] and early-type fractions (f_early_) and present these data for the individual groups.
- ID:
- ivo://CDS.VizieR/J/A+A/297/28
- Title:
- Dynamics in E+E pairs of galaxies
- Short Name:
- J/A+A/297/28
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present a kinematic study of three E+E galaxy pairs, NGC 741/742, 1587/1588 (CPG 99) and 2672/2673 (CPG 175). All three pairs show a similar morphological distortion (i.e. the off-centering of inner versus outer isophotes; Davoust & Prugniel 1988) which is ascribed to the ongoing interaction. The data was obtained at the CFHT equipped with the Herzberg Spectrograph at a resolution of 0.88 Apx^-1^. NGC 741 and 2673 show significant rotation along the apparent minor axis. Both components of CPG 99 rotate very fast (with no evidence for rotation along the minor axis of either component). None of the galaxies show abnormally high central velocity dispersion. We report some of the first clear detections of well defined velocity dispersion curves for interacting pairs. They show a systematic decrease with distance from the center, as expected for normal ellipticals. They do not show obvious heating in the outer parts as was previously reported. NGC 741 and 2672 show, respectively, possible U and inverse U-shaped structure in their velocity profiles.
- ID:
- ivo://CDS.VizieR/J/MNRAS/468/2645
- Title:
- Dynamics of A3266. I. An Optical View.
- Short Name:
- J/MNRAS/468/2645
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present spectroscopy of 880 galaxies within a 2-degree field around the massive, merging cluster Abell 3266. This sample, which includes 704 new measurements, was combined with the existing redshifts measurements to generate a sample of over 1300 spectroscopic redshifts; the largest spectroscopic sample in the vicinity of A3266 to date. We define a cluster sub-sample of 790 redshifts which lie within a velocity range of 14000 to 22000km/s and within 1 degree of the cluster centre. A detailed structural analysis finds A3266 to have a complex dynamical structure containing six groups and filaments to the north of the cluster as well as a cluster core which can be decomposed into two components split along a northeast-southwest axis, consistent with previous X-ray observations. The mean redshift of the cluster core is found to be 0.0594+/-0.0005 and the core velocity dispersion is given as 1462+/-99km/s. The overall velocity dispersion and redshift of the entire cluster and related structures are 1337+/-67 km/s and 0.0596+/-0.0002, respectively, though the high velocity dispersion does not represent virialised motions but rather is due to relative motions of the cluster components. We posit A3266 is seen following a merger along the northeast southwest axis, however, the rich substructure in the rest of the cluster suggests that the dynamical history is more complex than just a simple merger with a range of continuous dynamical interactions taking place. It is thus likely that turbulence in A3266 is very high, even for a merging cluster.
- ID:
- ivo://CDS.VizieR/J/A+AS/137/419
- Title:
- Dynamics of blue compact galaxies I. The data
- Short Name:
- J/A+AS/137/419
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Observations of six luminous blue compact galaxies (BCGs) and two star forming companion galaxies were carried out with the CIGALE scanning Fabry-Perot interferometer attached to the ESO 3.6m telescope on La Silla. The observations were made in the H-alpha emission line which is prominent in BCGs. A velocity sampling of 5km/s and a pixel size of 0.9arcseconds were used. In this paper we present the observations and the data together with the velocity fields and the derived rotation curves. In addition we provide rough estimates of the total dynamical mass and of the ionised gas mass for each galaxy. All galaxies display rotation, but while the companion galaxies have regular velocity fields, those of the BCGs are complex and appear perturbed. This is the most extensive study to date of the optical velocity fields of BCGs. The interpretation of these results will be presented in a forthcoming paper (Paper II).
- ID:
- ivo://CDS.VizieR/J/A+A/459/391
- Title:
- Dynamics of NGC 4636 globular cluster system
- Short Name:
- J/A+A/459/391
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the first dynamical study of the globular cluster system of NGC 4636. It is the southernmost giant elliptical galaxy of the Virgo cluster and is claimed to be extremely dark matter dominated, according to X-ray observations. Globular clusters are used as dynamical tracers to investigate, by stellar dynamical means, the dark matter content of this galaxy. Several hundred medium resolution spectra were acquired at the VLT with FORS 2/MXU. We obtained velocities for 174 globular clusters in the radial range 0.90'<R<15.5', or 0.5-9R_e_ in units of effective radius. Assuming a distance of 15Mpc, the clusters are found at projected galactocentric distances in the range 4 to 70kpc, the overwhelming majority within 30kpc. The measured line-of-sight velocity dispersions are compared to Jeans-models.