- ID:
- ivo://CDS.VizieR/J/A+A/641/A95
- Title:
- NGC 4104 g and r CFHT/Megacam images
- Short Name:
- J/A+A/641/A95
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Groups are the most common association of galaxies in the Universe and they are found in different configuration states, such as loose, compact, and fossil groups. We studied the galaxy group MKW 4s, dominated by the giant early-type galaxy NGC 4104 at z=0.0282, with the aim of understanding the evolutionary stage of this group and to place it within the framework of the standard {Lambda}CDM cosmological scenario. We obtained deep optical data with CFHT/Megacam (g and r bands) and we applied both the galfit 2D image fitting program and the IRAF/ellipse 1D radial method to model the brightest group galaxy (BGG) and its extended stellar envelope. We also analysed the publicly available XMM-Newton and Chandra X-ray data. From N-body simulations of dry-mergers with different mass ratios of the infalling galaxy, we were able to constrain the dynamical stage of this system. Our results show a stellar shell system feature in NGC 4104 and an extended envelope that was reproduced by our numerical simulations of a collision with a satellite galaxy taking place about 4-6Gyr ago. The initial pair of galaxies had a mass ratio of at least 1:3. Taking into account the stellar envelope contribution to the total r band magnitude and the X-ray luminosity, MKW 4s falls into the category of a fossil group. Our results show that we are witnessing a rare case of a shell elliptical galaxy in a forming fossil group.
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- ID:
- ivo://CDS.VizieR/J/A+A/654/A40
- Title:
- NGC1042 g and r deep final images
- Short Name:
- J/A+A/654/A40
- Date:
- 22 Feb 2022
- Publisher:
- CDS
- Description:
- We present the first results of the LBT Imaging of Galaxy Haloes and Tidal Structures (LIGHTS) survey. LIGHTS is an ongoing observational campaign with the 2x8.4m Large Binocular Telescope (LBT) aiming to explore the stellar haloes and the low surface brightness population of satellites down to a depth of mu_V_~31mag/arcsec^2^ (3s in 10"x10" boxes) of nearby galaxies. We simultaneously collected deep imaging in the g and r Sloan filters using the Large Binocular Cameras (LBCs). The resulting images are 60 times (i.e. 4.5mag) deeper than those from the Sloan Digital Sky Survey (SDSS), and they have characteristics comparable (in depth and spatial resolution) to the ones expected from the future Legacy Survey of Space and Time (LSST). Here we show the first results of our pilot programme targeting NGC1042 (an M33 analogue at a distance of 13.5Mpc) and its surroundings. The depth of the images allowed us to detect an asymmetric stellar halo in the outskirts of this galaxy whose mass (1.4+/-0.4x10^8^M_{sun}_) is in agreement with the Lambda Cold Dark Matter (LambdaCDM) expectations. Additionally, we show that deep imaging from the LBT reveals low mass satellites (a few times 10^5^M_{sun}_) with very faint central surface brightness mu_V(0)_~27mag/arcsec^2^(i.e. similar to Local Group dwarf spheroidals, such as Andromeda XIV or Sextans, but at distances well beyond the local volume). The depth and spatial resolution provided by the LIGHTS survey open up a unique opportunity to explore the `missing satellites' problem in a large variety of galaxies beyond our Local Group down to masses where the difference between the theory and observation (if any) should be significant.
- ID:
- ivo://CDS.VizieR/J/A+A/659/A45
- Title:
- NGC4330 GHASP and PUMA datacubes
- Short Name:
- J/A+A/659/A45
- Date:
- 04 Mar 2022 00:48:25
- Publisher:
- CDS
- Description:
- Using the VESTIGE survey, a deep narrow-band H{alpha} imaging survey of the Virgo cluster carried on at the CFHT with MegaCam, we have discovered a long and diffuse tail of ionised gas in the edge-on late-type galaxy NGC4330. This peculiar feature witnesses an ongoing ram pressure stripping event able to remove the gas in the outer region of the disc. Tuned hydrodynamic simulations suggest that the ram pressure stripping event is occurring almost face-on, making NGC4330 the ideal candidate to study the effects of the perturbation in the direction perpendicular to the disc plane. We present here two new independent sets of Fabry-Perot observations (R~10000) with the purpose of understanding the effects of ram pressure stripping process on the kinematics of the ionised gas. Despite their limited sensitivity to the diffuse gas emission, the data allowed us to measure the velocity and the velocity dispersion fields over the galaxy disc and in several features at the edges or outside the stellar disc formed after the ram pressure stripping event. We have constructed the position-velocity diagrams and the rotation curves of the galaxy using three different techniques. The data show, consistent with the hydrodynamic simulations, that the galaxy has an inner solid-body rotation up to ~2.4kpc, with noncircular streaming motions outwards the disc and in the several external features formed during the interaction of the galaxy with the surrounding intracluster medium. The data also indicate a decrease of the rotational velocity of the gas with increasing distance from the galaxy disc along the tails, suggesting a gradual but not linear loss of angular momentum in the stripped gas. Consistent with a ram pressure stripping scenario, the i-band image shows a boxy shape at the southwest edge of the disc, where the stellar orbits might have been perturbed by the modification of the gravitational potential well of the galaxy due to the displacement of the gas in the z-direction.
- ID:
- ivo://CDS.VizieR/J/ApJ/859/75
- Title:
- NGC 5824 giant star members from VLT obs.
- Short Name:
- J/ApJ/859/75
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- NGC 5824 is a massive Galactic globular cluster suspected to have an intrinsic spread in its iron content, according to the strength of the calcium triplet lines. We present chemical abundances of 117 cluster giant stars using high-resolution spectra acquired with the multi-object spectrograph FLAMES. The metallicity distribution of 87 red giant branch stars is peaked at [Fe/H]=-2.11+/-0.01dex, while that derived from 30 asymptotic giant branch stars is peaked at [Fe/H]=-2.20+/-0.01dex. Both the distributions are compatible with a null spread, indicating that this cluster did not retain the ejecta of supernovae. The small iron abundance offset between the two groups of stars is similar to the abundances already observed among red and asymptotic giant branch stars in other clusters. The lack of intrinsic iron spread rules out the possibility that NGC 5824 is the remnant of a disrupted dwarf galaxy, as previously suggested. We also find evidence of the chemical anomalies usually observed in globular clusters, namely the Na-O and the Mg-Al anticorrelations. In particular, NGC 5824 exhibits a huge range of [Mg/Fe] abundance, observed in only a few metal-poor and/or massive clusters. We conclude that NGC 5824 is a normal globular cluster, without spread in [Fe/H] but with an unusually large spread in [Mg/Fe], possibly due to an efficient self-enrichment driven by massive asymptotic giant branch stars.
- ID:
- ivo://CDS.VizieR/J/ApJ/671/1624
- Title:
- NGC 1533 globular cluster candidates
- Short Name:
- J/ApJ/671/1624
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We use two-band imaging data from the Advanced Camera for Surveys onboard the Hubble Space Telescope for a detailed study of NGC 1533, an SB0 galaxy in the Dorado group surrounded by a ring of HI.
- ID:
- ivo://CDS.VizieR/J/A+A/543/A131
- Title:
- NGC1316 globular cluster candidates photometry
- Short Name:
- J/A+A/543/A131
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present a catalog of point-like sources around NGC 1316, which forms the photometric database for our paper. This catalogue basically is a selection from a larger photometric database. The selection criteria are specified in the paper. The catalog contains coordinates, R magnitudes with uncertainties, C-R colors and their uncertainties as well as "sharp" and "chi" values from DAOPHOT II. The coordinates are for identification purposes only. Depending on the position, deviations of up to 1 arcsec may occur. See the paper for validity limits of the photometric calibration, particularly for very red colors.
- ID:
- ivo://CDS.VizieR/J/MNRAS/452/2208
- Title:
- NGC 4473 globular clusters
- Short Name:
- J/MNRAS/452/2208
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- NGC 4473 is a so-called double sigma (2{sigma}) galaxy, i.e. a galaxy with rare, double peaks in its 2D stellar velocity dispersion. Here, we present the globular cluster (GC) kinematics in NGC 4473 out to ~10R_e_ (effective radii) using data from combined Hubble Space Telescope/Advanced Camera for Surveys and Subaru/Suprime-Cam imaging and Keck/Deep Imaging Multi-Object Spectrograph. We find that the 2{sigma} nature of NGC 4473 persists up to 3R_e_, though it becomes misaligned to the photometric major axis. We also observe a significant offset between the stellar and GC rotation amplitudes. This offset can be understood as a co-addition of counter-rotating stars producing little net stellar rotation. We identify a sharp radial transition in the GC kinematics at ~4R_e_ suggesting a well defined kinematically distinct halo. In the inner region (<4R_e_), the blue GCs rotate along the photometric major axis, but in an opposite direction to the galaxy stars and red GCs. In the outer region (>4R_e_), the red GCs rotate in an opposite direction compared to the inner region red GCs, along the photometric major axis, while the blue GCs rotate along an axis intermediate between the major and minor photometric axes. We also find a kinematically distinct population of very red GCs in the inner region with elevated rotation amplitude and velocity dispersion. The multiple kinematic components in NGC 4473 highlight the complex formation and evolutionary history of this 2{sigma} galaxy, as well as a distinct transition between the inner and outer components.
- ID:
- ivo://CDS.VizieR/J/MNRAS/420/37
- Title:
- NGC 4365 globular clusters
- Short Name:
- J/MNRAS/420/37
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Analysis of the globular cluster (GC) system of the giant elliptical (E3) galaxy NGC 4365, from eight Hubble Space Telescope/Advanced Camera for Surveys pointings and a wide-field Subaru/Suprime-Cam image, is presented. Using magnitude, colour and size criteria, we obtain a catalogue of GC candidates. We also measure the photometric properties of the galaxy starlight, including a new measure of the effective radius.
- ID:
- ivo://CDS.VizieR/J/MNRAS/421/1485
- Title:
- NGC 3923 globular clusters
- Short Name:
- J/MNRAS/421/1485
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- This paper presents further results from our spectroscopic study of the globular cluster (GC) system of the group elliptical NGC 3923. From observations made with the GMOS instrument on the Gemini South Telescope, an additional 50 GC and ultra-compact dwarf (UCD) candidates have been spectroscopically confirmed as members of the NGC 3923 system. When the recessional velocities of these GCs are combined with the 29 GC velocities reported previously, a total sample of 79 GC/UCD velocities is produced. This sample extends to over 6-arcmin (>6Re~30kpc) from the centre of NGC 3923 and is used to study the dynamics of the GC system and the dark matter content of NGC 3923.
- ID:
- ivo://CDS.VizieR/J/ApJ/483/745
- Title:
- NGC 4478 globular clusters
- Short Name:
- J/ApJ/483/745
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We calculate the distance to NGC 4478, a neighbor of the giant Virgo elliptical M87, using the surface brightness fluctuations method on parallel data from the HST WFPC2 camera. The exposures considered were taken through the F814W filter, which approximates the Johnson I, and through the F606W filter, which is effectively a broad V filter. We describe the use of Fourier methods for separation of the fluctuations due to statistical variations in the projected number of stars per pixel (used to determine the distance) from fluctuations from other sources, which include photon noise, foreground stars, cosmic rays, and the variations due to the overall structure of the galaxy. The mean apparent magnitude of stars responsible for the measured fluctuations is m_I_{bar}=29.78+/-0.03, with an additional systematic uncertainty of 0.05mag. Using the latest calibration of Tonry (1997ApJ...475..399T), we obtain a distance of 15.6+/-1.0Mpc, which is consistent with the distance determined through the use of this method in the infrared K band by Pahre & Mould (1994ApJ...433..567P). We discuss the globular cluster (GC) luminosity function and color distribution, based on the ~130 candidates identified in the field. We find a roughly Gaussian luminosity function centered at m_v_=23.82+/-0.38 with {sigma}=1.16+/-0.21. The GC color distribution is also roughly Gaussian, centered at V-I=0.91+/-0.03, with {sigma}=0.20+/-0.03, and it is coincident to within the error bars with the blue peak of the bimodal color distribution found in M87. Comparing our data with recent evaluations of the GC color distribution at two different locations in M87 we find a trend of the red peak disappearing with radial distance. We speculate that this could be understood if the blue portion of the M87 GC population were acquired from its smaller companions. The specific frequency of globular clusters is among the lowest for elliptical galaxies, comparable only to the value found in M32. In both cases this may be a result of tidal truncation by a giant neighbor. This further indicates that clusters have been stripped from NGC 4478 by M87 and likely now are part of its globular cluster population.
