- ID:
- ivo://CDS.VizieR/J/A+A/638/A9
- Title:
- A census of the near-by Psc-Eri stellar stream
- Short Name:
- J/A+A/638/A9
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Within a sphere of 400pc radius around the Sun, we search for members of the Pisces-Eridanus (Psc-Eri) stellar stream in the Gaia Data Release 2 DR2) data set. We compare basic astrophysical characteristics of the stream with those of the Pleiades. We used a modified convergent-point method to identify stars with 2D - velocities consistent with the space velocity of the Psc-Eri stream and the Pleiades, respectively. We found 1387 members of the Psc-Eri stream in a G-magnitude range from 5.1mag to 19.3mag at distances between 80 and 380pc from the Sun. The stream has a nearly cylindrical shape with a length of at least 700pc and a thickness of 100pc. The accumulated stellar mass of the 1387 members amounts to about 770M_{sun}_, and the stream is gravitationally unbound. For the stream we found an age of about 135Myr. In many astrophysical properties Psc-Eri is comparable to the open cluster M45 (the Pleiades): in its age, its luminosity function (LF), its present-day mass function (PDMF) as well as in its total mass. Nonetheless, the two stellar ensembles are completely unlike in their physical appearance. We cautiously give two possible explanations for this disagreement: (i) the star-formation efficiency in their parental molecular clouds was higher for the Pleiades than for Psc-Eri or/and (ii) the Pleiades had a higher primordial mass segregation immediately after the expulsion of the molecular gas of the parental cloud.
Number of results to display per page
Search Results
- ID:
- ivo://CDS.VizieR/J/MNRAS/296/599
- Title:
- A3558 complex redshifts
- Short Name:
- J/MNRAS/296/599
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The Shapley Concentration is the richest supercluster of clusters in the nearby Universe, and its core is a remarkable complex formed by the ACO clusters A3558, A3562 and A3556, and by the two minor groups SC 1327-312 and SC 1329-314. This structure has been studied in various wavelength bands, revealing that it is probably dynamically very active. In this paper we present 174 new galaxy redshifts in this cluster complex, which are added to the sample of 540 already existing velocities. The spectroscopic observations were performed at the 3.6m ESO telescope at La Silla, equiped with the OPTOPUS multifibre spectrograph, on the nights 1993 February of 21-24.
- ID:
- ivo://CDS.VizieR/J/ApJ/893/77
- Title:
- A comprehensive statistical study of gamma-ray bursts
- Short Name:
- J/ApJ/893/77
- Date:
- 07 Mar 2022 07:29:40
- Publisher:
- CDS
- Description:
- In order to obtain an overview of gamma-ray bursts (GRBs), we need a full sample. In this paper, we collected 6289 GRBs (from GRB 910421 to GRB 160509A) from the literature, including their prompt emission, afterglow, and host galaxy properties. We hope to use this large sample to reveal the intrinsic properties of GRBs. We have listed all of the data in machine-readable tables, including the properties of the GRBs, correlation coefficients and linear regression results of two arbitrary parameters, and linear regression results of any three parameters. These machine-readable tables could be used as a data reservoir for further studies on the classifications or correlations. One may find some intrinsic properties from these statistical results. With these comprehensive tables, it is possible to find relations between different parameters and to classify the GRBs into different subgroups. Upon completion, they may reveal the nature of GRBs and may be used as tools like pseudo-redshift indicators, standard candles, etc.
- ID:
- ivo://CDS.VizieR/I/263
- Title:
- ACR catalog around Celestial Equator
- Short Name:
- I/263
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present improved and highly accurate International Celestial Reference System (ICRS) equatorial positions for 1,268,732 stars in 16 astrometric calibration regions located around the celestial equator. Each region is about 7.6{deg}x3.2{deg} in area (~24.3 deg^2^), contains a large number of stars (18,767 to 263,810), has stellar densities ranging from 765 to 10,772 stars deg^-2^, covers a wide range in magnitude (9.5<R<17.8, or equivalently 10.0<V<18.3), and is complete to magnitude R~17.2 (V~17.7). All of the observations were taken in 1994-1998 (mean epoch J1996.0) with the Flagstaff Astrometric Scanning Transit Telescope. Furthermore, each region was observed many times with overlapped CCD strip scans, and these data were reduced to star positions using differential reductions. The reference-star positions were taken from the ACT catalog of accurate star positions and proper motions. The star positions presented herein are typically accurate to +/-26mas (+/-12mas precision) in both right ascension and declination, except for the faintest stars, whose errors are about 2 times larger. Similarly, magnitudes were determined for the astrometric calibration stars using standard photometric reductions, and accuracies of +/-18mmag (+/-10mmag precisions) were achieved (about +/-46mmag for the faintest stars)
- ID:
- ivo://CDS.VizieR/J/ApJ/701/587
- Title:
- A deep HST H-band imaging survey. II. QUEST QSOs
- Short Name:
- J/ApJ/701/587
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We report the results from a deep Hubble Space Telescope (HST) NICMOS H-band imaging survey of 28 z<0.3 QSOs from the Palomar-Green (PG) sample. This program is part of QUEST (Quasar/ULIRG Evolution Study) and complements a similar set of data on 26 highly nucleated ULIRGs presented in Paper I (Veilleux et al. 2006ApJ...643..707V). Our analysis indicates that the fraction of QSOs with elliptical hosts is higher among QSOs with undetected far-infrared (FIR) emission, small infrared excess (L_IR_/L_B_<10), and luminous hosts. The hosts of FIR-faint QSOs show a tendency to have less pronounced merger-induced morphological anomalies and larger QSO-to-host luminosity ratios on average than the hosts of FIR-bright QSOs, consistent with late-merger evolution from FIR-bright to FIR-faint QSOs.
- ID:
- ivo://CDS.VizieR/J/ApJ/869/145
- Title:
- A 3D Voronoi+Gapper galaxy cluster finder. II.
- Short Name:
- J/ApJ/869/145
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We identify 1901 galaxy clusters (N_g_>=2) with the gapping-filtering in radial velocity (VoML+G) algorithm (Paper I; Campusano+ 2017ApJ...838..109P) on the two-Degree Field Galaxy Redshift Survey (2dFGRS). We present the 341 clusters with at least 10 galaxies that are within 0.009<z<0.14 (the Catalog), of which 254 (~75%) have counterparts in the literature (NED), with the remainder (87) plausibly "new" because of incompleteness of previous searches or unusual galaxy contents. The 207 clusters within z=0.04--0.09 are used to study the properties of the galaxy systems in the nearby universe, including their galaxy contents parameterized by the late-type galaxy fractions (f_L_). For this nearly complete cluster subsample, we find the following: (i) 63% are dominated by early-type galaxies (i.e., the late-type-poor clusters, f_L_<0.5) with corresponding mean multiplicity and logarithmic virial mass (in units of M_{sun}_) of 22+/-1 and 12.91+/-0.04, respectively; and (ii) 37% are dominated by late-type galaxies (i.e., the late-type-rich clusters, f_L_>=0.5) with corresponding mean multiplicity and logarithmic virial mass (in units of M_{sun}_) of 15.7+/-0.9 and 12.66+/-0.07, respectively. The statistical analysis of the late-type fraction distribution supports, with a 3{sigma} confidence level, the presence of two population components. It is suggested that the late-type-poor galaxy systems reflect and extend the class of Abell-APM-EDCC clusters and that the late-type-rich systems (~one-third of the total) belong to a new, previously unappreciated class. The late-type-rich clusters, on average high mass-to-light ratio systems, appear to be more clustered on large scales than the late-type-poor clusters. A class of late-type-rich clusters is not predicted by current theory.
- ID:
- ivo://CDS.VizieR/J/AJ/125/2393
- Title:
- A2256 galaxies redshifts and 1.4GHz fluxes
- Short Name:
- J/AJ/125/2393
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Abell 2256 is a nearby (z~0.06), rich cluster of galaxies with fascinating observed properties across a range of wavelengths. Long believed to represent a cluster merger, recent X-ray and optical results have suggested that in addition to the primary cluster and subcluster there is evidence for a third, poorer system. We present wide-field high-sensitivity 1.4GHz VLA radio observations of Abell 2256 in conjunction with optical imaging and additional spectroscopy. Over 40 cluster radio galaxies are identified, with optical spectroscopy indicating the emission source (star formation or active galactic nucleus) for most of them. While the overall fraction of galaxies exhibiting radio emission is consistent with a large sample of other nearby clusters, we find an increase in the activity level of galaxies belonging to the third system (hereafter "the Group"). Specifically, the Group has relatively more star formation than both the primary cluster and main subcluster. The position of the Group is also coincident with the observed cluster radio relic. We suggest that the Group recently (0.3Gyr) merged with the primary cluster and that this merger, not the ongoing merger of the primary and the main subcluster, might be responsible for many of the unusual radio properties of Abell 2256. Furthermore, the greater star formation activity of the Group suggests that the infall of groups is an important driver of galaxy evolution in clusters.
- ID:
- ivo://CDS.VizieR/J/ApJS/192/6
- Title:
- A GALEX UV imaging survey of nearby galaxies
- Short Name:
- J/ApJS/192/6
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present results from a GALEX ultraviolet (UV) survey of a complete sample of 390 galaxies within ~11Mpc of the Milky Way. The UV data are a key component of the composite Local Volume Legacy, an ultraviolet-to-infrared imaging program designed to provide an inventory of dust and star formation in nearby spiral and irregular galaxies. The ensemble data set is an especially valuable resource for studying star formation in dwarf galaxies, which comprise over 80% of the sample. We describe the GALEX survey programs that obtained the data and provide a catalog of far-UV (~1500{AA}) and near-UV (~2200{AA}) integrated photometry. General UV properties of the sample are briefly discussed. We compute two measures of the global star formation efficiency, the star formation rate (SFR) per unit HI gas mass, and the SFR per unit stellar mass, to illustrate the significant differences that can arise in our understanding of dwarf galaxies when the FUV is used to measure the SFR instead of H{alpha}.
- ID:
- ivo://CDS.VizieR/J/A+A/517/A50
- Title:
- Ages & luminosities of young SMC/LMC star clusters
- Short Name:
- J/A+A/517/A50
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- In this paper we discuss the age and spatial distribution of young (age<1Gyr) SMC and LMC clusters using data from the Magellanic Cloud Photometric Surveys. Luminosities are calculated for all age-dated clusters. Ages of 324 and 1193 populous star clusters in the Small and the Large Magellanic Cloud have been determined fitting Padova and Geneva isochrone models to their resolved color-magnitude diagrams. The clusters cover an age range between 10Myr and 1Gyr in each galaxy. For the SMC a constant distance modulus of (m-M)_0_=18.90 and a metallicity of Z=0.004 were adopted. For the LMC, we used a constant distance modulus of (m-M)_0_=18.50 and a metallicity of Z=0.008. For both galaxies, we used a variable color excess to derive the cluster ages. We find two periods of enhanced cluster formation in both galaxies at 160Myr and 630Myr (SMC) and at 125Myr and 800Myr (LMC). We present the spatially resolved recent star formation history of both Clouds based on young star clusters. The first peak may have been triggered by a close encounter between the SMC and the LMC. In both galaxies the youngest clusters reside in the supergiant shells, giant shells, the inter-shell regions, and toward regions with a high H\alpha content, suggesting that their formation is related to expansion and shell-shell interaction. Most of the clusters are older than the dynamical age of the supergiant shells. No evidence for cluster dissolution was found. Computed V band luminosities show a trend for fainter magnitudes with increasing age as well as a trend for brighter magnitudes with increasing apparent cluster radii.
20. AGK3 Catalogue
- ID:
- ivo://CDS.VizieR/I/61B
- Title:
- AGK3 Catalogue
- Short Name:
- I/61B
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The AGK3 provides positions and proper motions for stars north of -2.5 degrees. For the most part, it contains the stars in the AGK2 but is based on newly remeasured reference stars whose positions were reduced to the FK4 system. A list of 446 AGK2 stars not in the AGK3 and of three new stars is provided. All plates were taken at the Bergedorf Observatory. In addition to the positions and proper motions, the catalog contains magnitudes and spectral types, the epoch of the observations, the epoch difference between the AGK2 and AGK3, and the BD numbers.
