- ID:
- ivo://CDS.VizieR/J/A+A/591/A130
- Title:
- Dynamic SEDs of southern blazars - DSSB
- Short Name:
- J/A+A/591/A130
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Simultaneous broadband spectral and temporal studies of blazars are an important tool for investigating active galactic nuclei (AGN) jet physics. We study the spectral evolution between quiescent and flaring periods of 22 radio-loud AGN through multiepoch, quasi-simultaneous broadband spectra. For many of these sources these are the first broadband studies. We use a Bayesian block analysis of Fermi/LAT light curves to determine time ranges of constant flux for constructing quasi-simultaneous spectral energy distributions (SEDs). The shapes of the resulting 81 SEDs are described by two logarithmic parabolas and a blackbody spectrum where needed.
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- 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/ApJ/347/251
- Title:
- Dynamics of Globular Cluster M15
- Short Name:
- J/ApJ/347/251
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The velocity dispersion as a function of radius in the globular cluster M15 is derived from measurements of 120 individual stars between 0.1' and 4.6' of the cluster center, and from the integrated light of the central cusp. The stellar measurements, with an individual accuracy of 1 km/s, indicate a mean cluster velocity of -107.1+/-0.9 km/s, and a mean velocity dispersion of 9.0+/-0.6 km/s. The velocity dispersion inside 1' varies with radius. The dispersion of the 27 stars within 20" is 14.2+/-1.9 km/s, while that of the 30 stars between 0.5' and 1.2' is 8.4+/-1.4 km/s. The cusp itself appears to have a dispersion of at least 25 km/s. Except for its greater velocity broadening, the spectrum of the integrated light of the cusp is indistinguishable from that formed by superposition of the individual M15 giant spectra, demonstrating that the excess light at the center is due primarily to the normal M15 population. The increase of the dispersion toward the center is not consistent with truncated isothermal (King-Michie) models, for which the velocity dispersion is nearly constant within a few core radii and then falls steeply beyond. The observed behaviour is difficult to reconcile as well with current post-core collapse models, which are also isothermal and whose central energy sources are modest. It is indicative of a nonthermal energy distribution with substantial heating in the central regions; this is consistent with a central black hole of about 1000 M_{sun}_.
- ID:
- ivo://CDS.VizieR/J/AJ/106/1508
- Title:
- Dynamics of globular cluster NGC 362
- Short Name:
- J/AJ/106/1508
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- In this paper we have examined the internal dynamics of the globular cluster NGC 362 using a combination of V-band CCD images and echelle spectra of the member red giants. A V-band surface brightness profile (SBP) was constructed from the CCD images, and, after it was determined that the cluster is not post core-collapse, fit with single- and multi-pass King-Michie (KM) models. We found that for small values of the mass function slope, x, anisotropic models were favored while for steeper mass functions isotropic orbits provided superior fits. The total cluster luminosity is 1.70 +/- 0.1 x 10^5 L(Vsun) [assumes (m-M)0 = 14.77]. A total of 285 stellar spectra were obtained of 215 stars for radial velocity determinations. Three stars were obvious nonmembers and four showed strong evidence for radial velocity variations; these latter stars are probably members of binary systems with periods less than a few years. The true cluster binary fraction was determined from simulations to be 0.15 for circular orbits or 0.27 for orbits with a distribution function f(e) = e (e is eccentricity). This relatively high binary detection frequency may indicate that NGC 362 is overabundant in binaries compared to other clusters. The 208 remaining stellar velocities showed no sign of rotation and had kinematics which were incompatible with KM models having isotropic orbits and luminosity profiles consistent with the SBP. Therefore, the best agreement with both the kinematic data and the SBP were for shallow mass functions x = 0.0-0.5 and intermediate amounts of anisotropy in the velocity dispersion tensor. In this best-fit range, the derived cluster mass is M = 2.5-3.5x10^5 Msun for a global mass-to-light ratio of M/L(V) = 1.5-2.0 Msun/L(Vsun). This low value for x is in disagreement with the correlation between x and the height above the Galactic disk seen for a sample of other clusters. The results are also different from the sharp turnup in the low mass end of mass functions derived from the deep luminosity functions of three other globular clusters.
- ID:
- ivo://CDS.VizieR/J/A+A/604/A135
- Title:
- Dynamics of ionized and neutral gas in M8
- Short Name:
- J/A+A/604/A135
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present a spectroscopic study of the dynamics of the ionized and neutral gas throughout the Lagoon nebula (M8), using VLT/FLAMES data from the Gaia-ESO Survey. We explore the connections between the nebular gas and the stellar population of the associated star cluster NGC6530. We characterize through spectral fitting emission lines of H{alpha}, [NII] and [SII] doublets, [OIII], and absorption lines of sodium D doublet, using data from the FLAMES/Giraffe and UVES spectrographs, on more than 1000 sightlines towards the entire face of the Lagoon nebula. Gas temperatures are derived from line-width comparisons, densities from the [SII] doublet ratio, and ionization parameter from H{alpha}/[NII] ratio. Although doubly-peaked emission profiles are rarely found, line asymmetries often imply multiple velocity components along the same line of sight. This is especially true for the sodium absorption, and for the [OIII] lines. Spatial maps for density and ionization are derived, and compared to other known properties of the nebula and of its massive stars 9 Sgr, Herschel 36 and HD 165052 which are confirmed to provide most of the ionizing flux. The detailed velocity fields across the nebula show several expanding shells, related to the cluster NGC6530, the O stars 9 Sgr and Herschel 36, and the massive protostar M8East-IR. The origins of kinematical expansion and ionization of the NGC6530 shell appear to be different. We are able to put constrains on the line-of-sight (relative or absolute) distances between some of these objects and the molecular cloud. The large obscuring band running through the middle of the nebula is being compressed by both sides, which might explain its enhanced density. We also find an unexplained large-scale velocity gradient across the entire nebula. At larger distances, the transition from ionized to neutral gas is studied using the sodium lines.
- 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.
- ID:
- ivo://CDS.VizieR/J/ApJ/416/36
- Title:
- Dynamics of the Galaxy Cluster Abell 2634
- Short Name:
- J/ApJ/416/36
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Velocities are presented for 254 galaxies in the rich Abell cluster 2634. Positions are given for 274 additional galaxies for which further investigation is desirable.
- ID:
- ivo://CDS.VizieR/J/A+A/618/A186
- Title:
- Dynamic spectra of 10 pulsars
- Short Name:
- J/A+A/618/A186
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Pulsars scintillate. Dynamic spectra show brightness variation of pulsars in the time and frequency domain. Secondary spectra demonstrate the distribution of fluctuation power in the dynamic spectra. Dynamic spectra strongly depend on observational frequencies, but were often observed at frequencies lower than 1.5GHz. Scintillation observations at higher frequencies help to constrain the turbulence feature of the interstellar medium over a wide frequency range and can detect the scintillations of more distant pulsars. Ten pulsars were observed at 2250MHz (S-band) with the Jiamusi 66m telescope to study their scintillations. Their dynamic spectra were first obtained, from which the decorrelation bandwidths and time scales of diffractive scintillation were then derived by autocorrelation. Secondary spectra were calculated by forming the Fourier power spectra of the dynamic spectra. Most of the newly obtained dynamic spectra are at the highest frequency or have the longest time span of any published data for these pulsars. For PSRs B0540+23, B2324+60 and B2351+61, these were the first dynamic spectra ever reported. The frequency-dependence of scintillation parameters indicates that the intervening medium can rarely be ideally turbulent with a Kolmogorov spectrum. The thin screen model worked well at S-band for the scintillation of PSR B1933+16. Parabolic arcs were detected in the secondary spectra of three pulsars, PSRs B0355+54, B0540+23 and B2154+40, all of which were asymmetrically distributed. The inverted arclets of PSR B0355+54 were seen to evolve along the main parabola within a continuous observing session of 12 hours, from which the angular velocity of the pulsar was estimated that was consistent with the measurement by very long baseline interferometry (VLBI).