- ID:
- ivo://CDS.VizieR/J/MNRAS/477/1760
- Title:
- Antlia galaxies geometric parameters
- Short Name:
- J/MNRAS/477/1760
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present a statistical isophotal analysis of 138 early-type galaxies in the Antlia cluster, located at a distance of ~35Mpc. The observational material consists of CCD images of four 36x36arcmin^2^ fields obtained with the MOSAIC II camera at the Blanco 4-m telescope at Cerro Tololo Interamerican Observatory. Our present work supersedes previous Antlia studies in the sense that the covered area is four times larger, the limiting magnitude is M_B_~-9.6mag, and the surface photometry parameters of each galaxy are derived from Sersic model fits extrapolated to infinity. In a companion previous study we focused on the scaling relations obtained by means of surface photometry, and now we present the data, on which the previous paper is based, the parameters of the isophotal fits as well as an isophotal analysis. For each galaxy, we derive isophotal shape parameters along the semimajor axis and search for correlations within different radial bins. Through extensive statistical tests, we also analyse the behaviour of these values against photometric and global parameters of the galaxies themselves. While some galaxies do display radial gradients in their ellipticity ({epsilon}) and/or their Fourier coefficients, differences in mean values between adjacent regions are not statistically significant. Regarding Fourier coefficients, dwarf galaxies usually display gradients between all adjacent regions, while non-dwarfs tend to show this behaviour just between the two outermost regions. Globally, there is no obvious correlation between Fourier coefficients and luminosity for the whole magnitude range (-12>=M_V_>=-22); however, dwarfs display much higher dispersions at all radii.
Number of results to display per page
Search Results
- ID:
- ivo://CDS.VizieR/J/A+A/624/A145
- Title:
- Astrometric Catalogue 5, LQAC-5
- Short Name:
- J/A+A/624/A145
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- In addition to their great astrophysical interest, quasars represent quasi-ideal reference objects in the celestial sphere with, a priori, a lack of significant proper motion. Since the fourth release of the Large Quasar Astrometric Catalogue (LQAC-4), a large number of quasars have been discovered, in particular those coming from the DR14Q release of the SDSS. With the advent of the Gaia Data Release 2 (DR2), it is now also possible to fold in extremely accurate quasar positions. Following the same procedure as in the previous releases of the LQAC, our aim is to compile the large majority of the recorded quasars, with their best estimated coordinates and substantial information about their physical properties such as the redshift, multi-bands apparent, and absolute magnitudes. Emphasis is given to the results of the cross-matches with the Gaia DR2 catalogue, which considerably increases the positional accuracy. New quasars from the SDSS DR14Q release were cross-matched with the precedent LQAC-4 compilation with a 1" search radius, which leads to 149084 objects not present in the previous LQAC-4 release. Another cross-match was done with the Gaia DR2 catalogue, which enables us to considerably improve the positioning of these objects. For the first time, parallaxes and proper motions from the DR2, when available, are added to our compilation. Furthermore, a cross-identification of the LQAC-5 with the AllWISE survey gives additional mid-infrared information for an important percentage of objects. Our final catalogue, namely the LQAC-5, contains 592 809 quasars. This represents roughly a 34% increase with respect to the number of objects recorded in the LQAC-4. Among them, 398 697 objects were found in common with the Gaia DR2, within a 1" search radius. That corresponds to 67.26% of the whole population of the compilation. The LQAC-5 delivers a nearly complete catalogue of spectroscopically confirmed quasars (including a small proportion of 14126 compact AGN's) to the astronomical community, with the aim of giving their best equatorial coordinates with respect to the ICRF2 and with exhaustive additional information. For more than 50% of the sample, these coordinates are extracted from the very recent Gaia DR2.
- ID:
- ivo://CDS.VizieR/J/MNRAS/396/1231
- Title:
- Astrophotometric catalogue of NGC 891
- Short Name:
- J/MNRAS/396/1231
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present deep VI images obtained with the Advanced Camera for Surveys on board the Hubble Space Telescope, covering three fields in the north-east side of the edge-on disc galaxy NGC 891. The observed fields span a wide range of galactocentric distances along the eastern minor axis, extending from the plane of the disc to 12kpc, and out to ~25kpc along the major axis. The photometry of individual stars reaches ~2.5mag below the tip of the red giant branch. We use the astrophotometric catalogue to probe the stellar content and metallicity distribution across the thick disc and spheroid of NGC 891.
- ID:
- ivo://CDS.VizieR/J/A+A/457/517
- Title:
- ATESP 5 GHz radio survey. I.
- Short Name:
- J/A+A/457/517
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The nature and evolutionary properties of the faint radio population, responsible for the steepening observed in the 1.4GHz source counts below 1mJy, are not yet entirely clear. Radio spectral indices may help to constrain the origin of the radio emission in such faint radio sources and may be fundamental in understanding eventual links to the optical light. We study the spectral index behaviour of sources that were found in the 1.4GHz ATESP survey (Prandoni et al., 2000A&AS..146...31P & 2000, Cat. <VIII/63>), considering that the ATESP is one of the most extensive sub-mJy surveys existing at present. Using the Australia Telescope Compact Array we observed at 5GHz part of the region covered by the sub-mJy ATESP survey. In particular we imaged a one square degree area for which deep optical imaging in UBVRIJK is available. In this paper we present the 5GHz survey and source catalogue, we derive the 5GHz source counts and we discuss the 1.4-5GHz spectral index properties of the ATESP sources. The analysis of the optical properties of the sample will be the subject of a following paper.
- ID:
- ivo://CDS.VizieR/J/MNRAS/414/888
- Title:
- ATLAS3D project. III.
- Short Name:
- J/MNRAS/414/888
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We provide a census of the apparent stellar angular momentum within one effective radius of a volume-limited sample of 260 early-type galaxies (ETGs) in the nearby Universe, using the integral-field spectroscopy obtained in the course of the ATLAS3D project. We exploit the {lambda}_R_ parameter (previously used via a constant threshold value of 0.1) to characterize the existence of two families of ETGs: slow rotators which exhibit complex stellar velocity fields and often include stellar kinematically distinct cores, and fast rotators which have regular velocity fields. Our complete sample of 260 ETGs leads to a new criterion to disentangle fast and slow rotators which now includes a dependency on the apparent ellipticity {epsilon}.
- ID:
- ivo://CDS.VizieR/J/MNRAS/416/1680
- Title:
- ATLAS3D project. VII.
- Short Name:
- J/MNRAS/416/1680
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- In Paper I of this series we introduced a volume-limited parent sample of 871 galaxies from which we extracted the ATLAS3D sample of 260 early-type galaxies (ETGs). In Papers II and III we classified the ETGs using their stellar kinematics, in a way that is nearly insensitive to the projection effects, and we separated them into fast and slow rotators. Here we look at galaxy morphology and note that the edge-on fast rotators generally are lenticular galaxies.
- ID:
- ivo://CDS.VizieR/J/MNRAS/433/2812
- Title:
- ATLAS3D project. XXIII.
- Short Name:
- J/MNRAS/433/2812
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We investigate nuclear light profiles in 135 ATLAS3D galaxies for which the Hubble Space Telescope (HST) imaging is available and compare them to the large-scale kinematics obtained with the SAURON integral-field spectrograph. Specific angular momentum, {lambda}_R_, correlates with the shape of nuclear light profiles, where, as suggested by previous studies, cores are typically found in slow rotators and core-less galaxies are fast rotators. As also shown before, cores are found only in massive galaxies and only in systems with the stellar mass (measured via dynamical models) M>~8x10^10^M_{sun}_. Based on our sample, we, however, see no evidence for a bimodal distribution of nuclear slopes. The best predictor for finding a core is based on the stellar velocity dispersion within an effective radius, {sigma}_e_, and specific angular momentum, where cores are found for {lambda}_R<~0.25 and {sigma}_e_>~160km/s. We estimate that only about 10percent of nearby early-type galaxies contain cores. Furthermore, we show that there is a genuine population of fast rotators with cores. We also show that core fast rotators are morphologically, kinematically and dynamically different from core slow rotators. The cores of fast rotators, however, could harbour black holes of similar masses to those in core slow rotators, but typically more massive than those found in core-less fast rotators. Cores of both fast and slow rotators are made of old stars and found in galaxies typically lacking molecular or atomic gas (with a few exceptions). Core-less galaxies, and especially core-less fast rotators, are underluminous in the diffuse X-ray emission, but the presence of a core does not imply high X-ray luminosities. Additionally, we postulate (as many of these galaxies lack HST imaging) a possible population of core-less galaxies among slow rotators, which cannot be explained as face-on discs, but comprise a genuine sub-population of slow rotators. These galaxies are typically less massive and flatter than core slow rotators, and show evidence for dynamical cold structures and exponential photometric components. Based on our findings, major non-dissipative (gas-poor) mergers together with black hole binary evolution may not be the only path for formation of cores in early-type galaxies. We discuss possible processes for formation of cores and their subsequent preservation.
- ID:
- ivo://CDS.VizieR/J/MNRAS/446/120
- Title:
- ATLAS3D project. XXIX
- Short Name:
- J/MNRAS/446/120
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Galactic archaeology based on star counts is instrumental to reconstruct the past mass assembly of Local Group galaxies. The development of new observing techniques and data reduction, coupled with the use of sensitive large field of view cameras, now allows us to pursue this technique in more distant galaxies exploiting their diffuse low surface brightness (LSB) light. As part of the ATLAS3D project, we have obtained with the MegaCam camera at the Canada-France-Hawaii Telescope extremely deep, multiband images of nearby early-type galaxies (ETGs). We present here a catalogue of 92 galaxies from the ATLAS3D sample, which are located in low- to medium-density environments. The observing strategy and data reduction pipeline, which achieve a gain of several magnitudes in the limiting surface brightness with respect to classical imaging surveys, are presented. The size and depth of the survey are compared to other recent deep imaging projects. The paper highlights the capability of LSB-optimized surveys at detecting new prominent structures that change the apparent morphology of galaxies. The intrinsic limitations of deep imaging observations are also discussed, among those, the contamination of the stellar haloes of galaxies by extended ghost reflections, and the cirrus emission from Galactic dust. The detection and systematic census of fine structures that trace the present and past mass assembly of ETGs are one of the prime goals of the project. We provide specific examples of each type of observed structures - tidal tails, stellar streams and shells - and explain how they were identified and classified. We give an overview of the initial results. The detailed statistical analysis will be presented in future papers.
- ID:
- ivo://CDS.VizieR/J/MNRAS/458/2221
- Title:
- ATLAS3D Project. XXXI
- Short Name:
- J/MNRAS/458/2221
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the results of a high-resolution, 5GHz, Karl G. Jansky Very Large Array study of the nuclear radio emission in a representative subset of the atlas^3D^ survey of early-type galaxies (ETGs). We find that 51+/-4 per cent of the ETGs in our sample contain nuclear radio emission with luminosities as low as 10^18^W/Hz. Most of the nuclear radio sources have compact (<~25-110pc) morphologies, although ~10 per cent display multicomponent core+jet or extended jet/lobe structures. Based on the radio continuum properties, as well as optical emission line diagnostics and the nuclear X-ray properties, we conclude that the majority of the central 5GHz sources detected in the atlas^3D^ galaxies are associated with the presence of an active galactic nucleus (AGN). However, even at subarcsecond spatial resolution, the nuclear radio emission in some cases appears to arise from low-level nuclear star formation rather than an AGN, particularly when molecular gas and a young central stellar population is present. This is in contrast to popular assumptions in the literature that the presence of a compact, unresolved, nuclear radio continuum source universally signifies the presence of an AGN. Additionally, we examine the relationships between the 5 GHz luminosity and various galaxy properties including the molecular gas mass and - for the first time - the global kinematic state. We discuss implications for the growth, triggering, and fuelling of radio AGNs, as well as AGN-driven feedback in the continued evolution of nearby ETGs.
- ID:
- ivo://CDS.VizieR/J/A+A/591/A5
- Title:
- ATLASGAL dense filamentary structures
- Short Name:
- J/A+A/591/A5
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We study the properties of filamentary structures from the ATLASGAL survey. We use the DisPerSE algorithm to identify spatially coherent structures located across the inner-Galaxy (300<l<60 and |b|<1.5). We have determined distances, masses and physical sizes for 241 of the filamentary structures. We find a median distance of 3.8kpc, a mean mass of a few 10^3^M_{sun}_, a mean length of ~6pc and a mass-to-length ratio of (M/L)~200-2000M_sun/pc. We also find that these filamentary structures are tightly correlated with the spiral arms in longitude and velocity, and that their semi-major axis is preferentially aligned parallel to the Galactic mid-plane and therefore with the direction of large-scale Galactic magnetic field. We find many examples where the dense filaments identified in ATLASGAL are associated with larger scale filamentary structures (~100pc), and argue that this is likely to be common, and as such these may indicate a connection between large-scale Galactic dynamics and star formation. We have produced a large and Galaxy-wide catalogue of dense filamentary structures that are representative of a particular size and mass range not previously well studied in the literature. Analyses of the properties and distribution of these filaments reveals that they are correlated with the spiral arms and make a significant contribution to star formation in the Galaxy. Massive star formation is ongoing within ~20% of the filaments and is strongly correlated with the filaments with the largest mass-to- length ratios. The luminosity of the embedded sources has a similar distribution to the Galactic-wide samples of young massive stars and can therefore be considered to be representative.
