Number of results to display per page
Search Results
- ID:
- ivo://CDS.VizieR/J/A+AS/145/263
- Title:
- Kinematical data on early-type galaxies. V.
- Short Name:
- J/A+AS/145/263
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present kinematical data for a sample of 26 galaxies. Rotation curves and velocity-dispersion profiles are determined for all objects. This is our fifth paper in a series devoted to the presentation of data on elliptical and S0 galaxies, derived from long-slit absorption spectroscopy; the series now gathers 119 galaxies with homogeneous data.
- ID:
- ivo://CDS.VizieR/J/A+A/384/371
- Title:
- Kinematical data on early-type galaxies. VI
- Short Name:
- J/A+A/384/371
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the result of spectroscopic observations of a sample of 73 galaxies, completing the database published in this series of articles. The sample contains mostly low-luminosity early-type objects, including four dwarfs of the Local Group (in particular, deep spectra of NGC 205), 15 dEs or dS0s in the Virgo cluster, and UGC 05442, a spheroidal dwarf of the M81 group. We have measured the central velocity dispersion for all but one object, and determined the major-axis rotation and velocity-dispersion profiles for 59 objects. For the current sample of diffuse (or dwarf) elliptical galaxies, we have compared stellar rotation to velocity dispersion; the analysis suggests that these objects may be nearly rotationally flattened, and therefore that anisotropy may be less important than previously thought.
- ID:
- ivo://CDS.VizieR/J/ApJ/768/172
- Title:
- Kinematic analysis of red giant in M31 dSphs
- Short Name:
- J/ApJ/768/172
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present a homogeneous kinematic analysis of red giant branch stars within 18 of the 28 Andromeda dwarf spheroidal (dSph) galaxies, obtained using the Keck I/LRIS and Keck II/DEIMOS spectrographs. Based on their g-i colors (taken with the CFHT/MegaCam imager), physical positions on the sky, and radial velocities, we assign probabilities of dSph membership to each observed star. Using this information, the velocity dispersions, central masses, and central densities of the dark matter halos are calculated for these objects, and compared with the properties of the Milky Way dSph population. We also measure the average metallicity ([Fe/H]) from the co-added spectra of member stars for each M31 dSph and find that they are consistent with the trend of decreasing [Fe/H] with luminosity observed in the Milky Way population. We find that three of our studied M31 dSphs appear as significant outliers in terms of their central velocity dispersion, And XIX, XXI, and XXV, all of which have large half-light radii (>~700pc) and low velocity dispersions ({sigma}_v_<5km/s). In addition, And XXV has a mass-to-light ratio within its half-light radius of just [M/L]_half_=10.3_-6.7_^7.0^, making it consistent with a simple stellar system with no appreciable dark matter component within its 1{sigma} uncertainties. We suggest that the structure of the dark matter halos of these outliers have been significantly altered by tides.
- ID:
- ivo://CDS.VizieR/J/ApJ/858/118
- Title:
- Kinematic data of 3 nearby low-mass galaxies
- Short Name:
- J/ApJ/858/118
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present a detailed study of the nuclear star clusters (NSCs) and massive black holes (BHs) of four of the nearest low-mass early-type galaxies: M32, NGC 205, NGC 5102, and NGC 5206. We measure the dynamical masses of both the BHs and NSCs in these galaxies using Gemini/NIFS or VLT/SINFONI stellar kinematics, Hubble Space Telescope (HST) imaging, and Jeans anisotropic models. We detect massive BHs in M32, NGC 5102, and NGC 5206, while in NGC 205, we find only an upper limit. These BH mass estimates are consistent with previous measurements in M32 and NGC 205, while those in NGC 5102 and NGC 5206 are estimated for the first time and both found to be <10^6^M_{sun}_. This adds to just a handful of galaxies with dynamically measured sub-million M_{sun}_ central BHs. Combining these BH detections with our recent work on NGC 404's BH, we find that 80% (4/5) of nearby, low-mass (10^9^-10^10^M_{sun}_; {sigma}_*_~20-70km/s) early-type galaxies host BHs. Such a high occupation fraction suggests that the BH seeds formed in the early epoch of cosmic assembly likely resulted in abundant seeds, favoring a low-mass seed mechanism of the remnants, most likely from the first generation of massive stars. We find dynamical masses of the NSCs ranging from 2 to 73x10^6^M_{sun}_ and compare these masses to scaling relations for NSCs based primarily on photometric mass estimates. Color gradients suggest that younger stellar populations lie at the centers of the NSCs in three of the four galaxies (NGC 205, NGC 5102, and NGC 5206), while the morphology of two are complex and best fit with multiple morphological components (NGC 5102 and NGC 5206). The NSC kinematics show they are rotating, especially in M32 and NGC 5102 (V/{sigma}_*_~0.7).
- ID:
- ivo://CDS.VizieR/J/AJ/113/950
- Title:
- Kinematic Profiles of S0 Galaxies
- Short Name:
- J/AJ/113/950
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Stellar rotation curves, velocity dispersion profiles, and line of sight velocity distributions (LOSVD) as derived from absorption-lines are presented for the major axes of 18 S0 and two elliptical galaxies. Ionized gas rotation curves and dispersions were measured from the [OIII] 5007A emission line in the 9 S0 galaxies displaying this feature. Minor-axis results are given for 14 of the S0 galaxies and one of the ellipticals. A wide range of behaviors are observed in the rotation and velocity dispersion profiles. These variations could be the result of the superposition of stars and gas belonging to the disks and bulges as well as the possible influences of bars, nuclear disks, and warps. Deviations from a Gaussian LOSVD are found along the major axes of all the galaxies in our sample. As parametrised by the Gauss-Hermite series of orthogonal functions, asymmetric deviations are always found in the inner regions of the S0 galaxies such that the prograde wing of the LOSVD is steeper than the retrograde wing. This is similar to the behavior observed in elliptical galaxies. However, at larger radii these asymmetries can change their sign. We find that in 9 of the 18 S0 galaxies a high-speed tail to the LOSVD develops along the major-axis beyond the central regions. In 3 of these 9 objects the LOSVD asymmetries display a second change of sign with radius such that a low-speed tail is again present and persists to our last measured values. No correlations were found between the sizes of the stellar velocity dispersion gradients and either central velocity dispersion, absolute magnitude, disk-to-bulge ratio, Mg2 or Fe line strength gradients. For the objects in our sample with edge-on orientations a comparison between the minor-axis 'bulge' velocity dispersion gradients and those found in elliptical galaxies indicates that the S0 bulges display, on average, logarithmic gradients approximately 4 times steeper than those found in normal luminous ellipticals. A number of galaxies show particularly interesting features. For the LINER S0 galaxy NGC 3998 we find that the velocity dispersion profiles of both the stars and gas rise sharply towards the center reaching nuclear values of sigma~320km/s. Nuclear disks of rapidly rotating gas are found in NGC 4350 and NGC 4762. A nuclear stellar disk is apparent in the edge-on galaxy NGC 4111 and an extended disk of counterrotating gas is observed in the barred S0 NGC 3941.
- ID:
- ivo://CDS.VizieR/J/A+A/526/A114
- Title:
- Kinematic profiles of Virgo early-type galaxies
- Short Name:
- J/A+A/526/A114
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present new medium resolution kinematic data for a sample of 21 dwarf early-type galaxies (dEs) mainly in the Virgo cluster, obtained with the WHT and INT telescopes at the Roque de los Muchachos Observatory (La Palma, Spain). These data are used to study the origin of the dwarf elliptical galaxy population inhabiting clusters.
- ID:
- ivo://CDS.VizieR/J/ApJ/668/94
- Title:
- Kinematics across the Hubble sequence
- Short Name:
- J/ApJ/668/94
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The correlation between the maximum rotational velocity of the disk (vm) and the central stellar velocity dispersion of the bulge (sigma0) offers insights into the relationship between the halo and the bulge. We have assembled integrated HI line widths and central stellar velocity dispersions to study the vm-sigma0 relation for 792 galaxies spanning a broad range of Hubble types.
- ID:
- ivo://CDS.VizieR/J/A+A/424/447
- Title:
- Kinematics in 17 nearby spiral galaxies
- Short Name:
- J/A+A/424/447
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Ionized gas and stellar kinematics have been measured along the major axes of seventeen nearby spiral galaxies of intermediate to late morphological type. We discuss the properties of each sample galaxy, distinguishing between those characterized by regular or peculiar kinematics. In most of the observed galaxies, ionized gas rotates more rapidly than stars and has a lower velocity dispersion, as is to be expected if the gas is confined in the disc and supported by rotation while the stars are mostly supported by dynamical pressure. In a few objects, gas and stars show almost the same rotational velocity and low velocity dispersion, suggesting that their motion is dominated by rotation. Incorporating the spiral galaxies studied by Bertola et al. (1996ApJ...458L..67B), Corsini et al. (1999, Cat. <J/A+A/342/671>, 2003, Cat. <J/A+A/408/873>) and Vega Beltran et al. (2001, Cat. <J/A+A/374/394>) we have compiled a sample of 50 S0/a-Scd galaxies, for which the major-axis kinematics of the ionized gas and stars have been obtained with the same spatial (~1") and spectral (~50km/s) resolution, and measured with the same analysis techniques.
- ID:
- ivo://CDS.VizieR/J/ApJ/725/670
- Title:
- Kinematics in the M32 nucleus
- Short Name:
- J/ApJ/725/670
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Using adaptive optics assisted Gemini/NIFS data, I study the present and past gas accretion in the central 3" of the M32 nucleus. From changes in the spectral slope and CO line depths near the center, I find evidence for unresolved dust emission resulting from black hole (BH) accretion. With a luminosity of ~2x10^38^erg/s, this dust emission appears to be the most luminous tracer of current BH accretion, 2 orders of magnitude more luminous than previously detected X-ray emission. These observations suggest that using high-resolution infrared data to search for dust emission may be an effective way to detect other nearby, low-luminosity BHs, such as those in globular clusters. I also examine the fossil evidence of gas accretion contained in the kinematics of the stars in the nucleus. The higher order moments (h3 and h4) of the line-of-sight velocity distribution show patterns that are remarkably similar to those seen on larger scales in elliptical galaxies and in gas-rich merger simulations. The kinematics suggests the presence of two components in the M32 nucleus, a dominant disk overlying a pressure supported component.
