- ID:
- ivo://CDS.VizieR/J/A+A/614/A140
- Title:
- Large Quasar Astrometric Catalogue 4, LQAC-4
- Short Name:
- J/A+A/614/A140
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- From an astrometric point of view, quasars constitute the best and almost ideal reference objects in the celestial sphere, with a priori no significant proper motion. Since the third release of the Large Quasar Astrometric Catalogue (LQAC-3, Cat. J/A+A/583/A75), a large number of quasars have been discovered, in particular those coming from the DR12Q release of the SDSS (Paris et al., 2017, Cat. VII/279). Moreover, for cross-matched objects, we have taken advantage of the very accurate determinations of the quasars identified within the recent Gaia DR1 catalogue (2018, Cat. I/345). Following the same procedure as in the three previous releases of the LQAC, our aim is to compile the large majority of all the quasars recorded so far. Our goal is to record their best coordinates and substantial information concerning their physical properties such as the redshift as well as multi-bands apparent and absolute magnitudes. Emphasis is given to the results of the cross-matches with the Gaia DR1 catalogue. New quasars coming from the DR12Q release were cross-matched with the precedent LQAC-3 compilation with a 1" search radius, in order to add the objects without counterpart to the LQAC-4 compilation. A similar cross-match was done with Gaia DR1 to identify the known quasars detected by Gaia. This enables one to improve significantly the positioning of these objects, and in parallel to study the astrometric performance of the individual catalogues of the LQAC-4 compilation. Finally, a new method was used to determine absolute magnitudes. Our final catalogue, called LQAC-4, contains 443 725 objects. This is roughly 37.82% more than the number of objects recorded in the LQAC-3. Among them, 249071 were found in common with the Gaia DR1, with a 1" search radius. That corresponds to 56.13% of the whole population in the compilation. The LQAC-4 delivers to the astronomical community a nearly complete catalogue of spectroscopically confirmed quasars (including a small proportion of compact AGNs), 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 come from the very recent Gaia DR1.
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Search Results
- ID:
- ivo://CDS.VizieR/J/A+A/547/A12
- Title:
- Leading arm Magellanic Cloud Catalog
- Short Name:
- J/A+A/547/A12
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The Magellanic Cloud system (MCS) interacts via tidal and drag forces with the Milky Way galaxy. Using the Parkes Galactic All-Sky Survey (GASS) of atomic hydrogen we explore the role of drag on the evolution of the so-called Leading Arm (LA).
- ID:
- ivo://CDS.VizieR/J/MNRAS/459/3130
- Title:
- Lists of arm and interarm supernovae
- Short Name:
- J/MNRAS/459/3130
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Using a sample of 215 supernovae (SNe), we analyse their positions relative to the spiral arms of their host galaxies, distinguishing grand-design (GD) spirals from non-GD (NGD) galaxies. We find that: (1) in GD galaxies, an offset exists between the positions of Ia and core-collapse (CC) SNe relative to the peaks of arms, while in NGD galaxies the positions show no such shifts; (2) in GD galaxies, the positions of CC SNe relative to the peaks of arms are correlated with the radial distance from the galaxy nucleus. Inside (outside) the corotation radius, CC SNe are found closer to the inner (outer) edge. No such correlation is observed for SNe in NGD galaxies nor for SNe Ia in either galaxy class; (3) in GD galaxies, SNe Ibc occur closer to the leading edges of the arms than do SNe II, while in NGD galaxies they are more concentrated towards the peaks of arms. In both samples of hosts, the distributions of SNe Ia relative to the arms have broader wings. These observations suggest that shocks in spiral arms of GD galaxies trigger star formation in the leading edges of arms affecting the distributions of CC SNe (known to have short-lived progenitors). The closer locations of SNe Ibc versus SNe II relative to the leading edges of the arms supports the belief that SNe Ibc have more massive progenitors. SNe Ia having less massive and older progenitors, have more time to drift away from the leading edge of the spiral arms.
- ID:
- ivo://CDS.VizieR/J/AJ/142/48
- Title:
- LMC star clusters structural parameters
- Short Name:
- J/AJ/142/48
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present and analyze the radial luminosity profiles of a sample of 1066 stellar clusters in the Large Magellanic Cloud (LMC). By design, this study closely follows the compilation by Hill & Zaritsky (2006, Cat. J/AJ/131/414 of the structural parameters of stellar clusters in the Small Magellanic Cloud (SMC). Both King and Elson-Fall-Freeman model profiles are fit to V-band surface brightness profiles measured from the Magellanic Cloud Photometric Survey images. We tabulate the concentration, central surface brightness, tidal radii, 90% enclosed luminosity radii (r_90_), and local background luminosity density. Over two-thirds of the clusters in the sample are adequately fit by one or both of these models. One notable and systematic exception, as in the SMC, is those clusters that lack a central brightness concentration, the "ring" clusters. While the bulk properties of the clusters are similar between the LMC and SMC populations, we find that the LMC lacks clusters that are as large, either in terms of core radii or r90, as the largest in the SMC, perhaps a signature of larger tidal stresses in the LMC.
- ID:
- ivo://CDS.VizieR/J/A+A/398/479
- Title:
- Local galaxy flows within 5 Mpc
- Short Name:
- J/A+A/398/479
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present Hubble Space Telescope/WFPC2 images of sixteen dwarf galaxies as part of our snapshot survey of nearby galaxy candidates. We derive their distances from the luminosity of the tip of the red giant branch stars with a typical accuracy of ~12%.
- ID:
- ivo://CDS.VizieR/J/A+A/343/93
- Title:
- Local radio luminosity function of galaxies. II.
- Short Name:
- J/A+A/343/93
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Using new extensive radio continuum surveys at 1.4GHz (FIRST and NVSS), we derive the distribution of the radio/optical and radio/NIR luminosity (RLF) of late-type (Sa-Irr) galaxies (m_p_<15.7) in 5 nearby clusters of galaxies: A262, Cancer, A1367, Coma and Virgo. With the aim of discussing possible environmental dependences of the radio properties, we compare these results with those obtained for relatively isolated objects in the Coma supercluster. We find that the RLF of Cancer, A262 and Virgo are consistent with that of isolated galaxies. Conversely we confirm earlier claims that galaxies in A1367 and Coma have their radio emissivity enhanced by a factor ~5 with respect to isolated objects. We discuss this result in the framework of the dynamical pressure suffered by galaxies in motion through the intra-cluster gas (ram-pressure). We find that the radio excess is statistically larger for galaxies in fast transit motion. This is coherent with the idea that enhanced radio continuum activity is associated with magnetic field compression. The X-ray luminosities and temperatures of Coma and A1367 imply that these two clusters have significantly larger intracluster gas density than the remaining three studied ones, providing a clue for explaining the higher radio continuum luminosities of their galaxies. Multiple systems in the Coma supercluster bridge (with projected separations smaller than 300kpc) have radio luminosities significantly larger than isolated galaxies.
- ID:
- ivo://CDS.VizieR/J/AJ/158/122
- Title:
- Local structure & star formation history of the MW
- Short Name:
- J/AJ/158/122
- Date:
- 09 Mar 2022 22:00:00
- Publisher:
- CDS
- Description:
- Gaia DR2 (Cat. I/345) provides unprecedented precision in measurements of the distance and kinematics of stars in the solar neighborhood. Through applying unsupervised machine learning on DR2's 5D data set (3D position + 2D velocity), we identify a number of clusters, associations, and comoving groups within 1 kpc and |b|<30{deg} (many of which have not been previously known). We estimate their ages with the precision of ~0.15 dex. Many of these groups appear to be filamentary or string-like, oriented in parallel to the Galactic plane, and some span hundreds of parsec in length. Most of these string lack a central cluster, indicating that their filamentary structure is primordial, rather than the result of tidal stripping or dynamical processing. The youngest strings (<100 Myr) are orthogonal to the Local Arm. The older ones appear to be remnants of several other arm-like structures that cannot be presently traced by dust and gas. The velocity dispersion measured from the ensemble of groups and strings increase with age, suggesting a timescale for dynamical heating of ~300 Myr. This timescale is also consistent with the age at which the population of strings begins to decline, while the population in more compact groups continues to increase, suggesting that dynamical processes are disrupting the weakly bound string populations, leaving only individual clusters to be identified at the oldest ages. These data shed a new light on the local galactic structure and a large-scale cloud collapse.
- ID:
- ivo://CDS.VizieR/J/AJ/153/6
- Title:
- Local Tully-Fisher relation for dwarf galaxies
- Short Name:
- J/AJ/153/6
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We study different incarnations of the Tully-Fisher (TF) relation for the Local Volume (LV) galaxies taken from Updated Nearby Galaxy Catalog. The UNGC sample contains 656 galaxies with W_50_ HI-line-width estimates, mostly belonging to low-mass dwarfs. Of them, 296 objects have distances measured with accuracies better than 10%. For the sample of 331 LV galaxies having baryonic masses logM_bar_>5.8logM_{Sun}_, we obtain a relation logM_bar_=2.49logW_50_+3.97 with an observed scatter of 0.38dex. The largest factors affecting the scatter are observational errors in K-band magnitudes and W_50_ line widths for the tiny dwarfs, as well as uncertainty of their inclinations. We find that accounting for the surface brightness of the LV galaxies or their gas fraction, specific star-formation rate, or isolation index does not essentially reduce the observed scatter on the baryonic TF diagram. We also notice that a sample of 71 dSph satellites of the Milky Way and M31 with a known stellar velocity dispersion {sigma}* tends to follow nearly the same bTF relation, having slightly lower masses than that of late-type dwarfs.
- ID:
- ivo://CDS.VizieR/J/MNRAS/495/4071
- Title:
- Lockman Hole region 325MHz source catalogue
- Short Name:
- J/MNRAS/495/4071
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- One of the key science goals for the most sensitive telescopes, both current and upcoming, is the detection of the redshifted 21-cm signal from the Cosmic Dawn and Epoch of Reionization. The success of detection relies on accurate foreground modelling for their removal from data sets. This paper presents the characterization of astrophysical sources in the Lockman Hole region. Using 325-MHz data obtained from the Giant Metrewave Radio Telescope, a 6{deg}x6{deg} mosaiced map is produced with an rms reaching 50uJy per beam. A source catalogue containing 6186 sources is created, and the Euclidean normalized differential source counts have been derived from it, consistent with previous observations as well as simulations. A detailed comparison of the source catalogue is also made with previous findings - at both lower and higher frequencies. The angular power spectrum (APS) of the diffuse Galactic synchrotron emission is determined for three different Galactic latitudes using the tapered gridded estimator. The values of the APS lie between ~1 and ~100mK^2^. Fitting a power law of the form Al^-{beta}^ gives values of A and {beta} varying across the latitudes considered. This paper demonstrates, for the first time, the variation of the power-law index for diffuse emission at very high Galactic locations. It follows the same trend that is seen at locations near the Galactic plane, thus emphasizing the need for low-frequency observations for developing better models of the diffuse emission.
- ID:
- ivo://CDS.VizieR/J/A+A/622/A4
- Title:
- LOFAR observations XMM-LSS field
- Short Name:
- J/A+A/622/A4
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present observations of the XMM Large-Scale Structure (XMM-LSS) field observed with the LOw Frequency ARray (LOFAR) at 120-168MHz. Centred at a J2000 declination of -4.5{deg}, this is a challenging field to observe with LOFAR because of its low elevation with respect to the array. The low elevation of this field reduces the effective collecting area of the telescope, thereby reducing sensitivity. This low elevation also causes the primary beam to be elongated in the north-south direction, which can introduce side lobes in the synthesised beam in this direction. However the XMM-LSS field is a key field to study because of the wealth of ancillary information, encompassing most of the electromagnetic spectrum. The field was observed for a total of 12 hours from three four-hour LOFAR tracks using the Dutch array. The final image presented encompasses ~27deg^2^, which is the region of the observations with a >50% primary beam response. Once combined, the observations reach a central rms of 280uJy/beam at 144MHz and have an angular resolution of 7.5x8.5". We present our catalogue of detected sources and investigate how our observations compare to previous radio observations. This includes investigating the flux scale calibration of these observations compared to previous measurements, the implied spectral indices of the sources, the observed source counts and corrections to obtain the true source counts, and finally the clustering of the observed radio sources.
