- ID:
- ivo://CDS.VizieR/J/A+A/626/A80
- Title:
- Census of Rho Oph candidate members from Gaia DR2
- Short Name:
- J/A+A/626/A80
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The Ophiuchus cloud complex is one of the best laboratories to study the earlier stages of the stellar and protoplanetary disc evolution. We constructed a control sample composed of 188 bona fide Ophiuchus members. Using this sample as a reference we applied three different density-based machine learning clustering algorithms (DBSCAN, OPTICS, and HDBSCAN) to a sample drawn from the Gaia DR2 catalogue centred on the Ophiuchus cloud that contains 2300 sources covering a sky area of 38deg^2^. The clustering analysis was applied in the five astrometric dimensions defined by the three-dimensional Cartesian space and the proper motions in right ascension and declination. The three clustering algorithms systematically identify a similar set of candidate members in a main cluster with astrometric properties consistent with those of the control sample. We constructed a common sample containing 391 member candidates including 166 new objects, which have not yet been discussed in the literature. We built the SEDs for a subset of 48 objects and found a total of 41 discs.
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Search Results
- ID:
- ivo://CDS.VizieR/J/ApJ/715/1094
- Title:
- Census of self-obscured massive stars
- Short Name:
- J/ApJ/715/1094
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- A new link in the causal mapping between massive stars and potentially fatal explosive transients opened with the 2008 discovery of the dust-obscured progenitors of the luminous outbursts in NGC 6946 and NGC 300. Here, we carry out a systematic mid-IR photometric search for massive, luminous, and self-obscured stars in four nearby galaxies: M33, NGC 300, M81, and NGC 6946. For detection, we use only the 3.6um and 4.5um IRAC bands, as these can still be used for multi-epoch Spitzer surveys of nearby galaxies (<~10Mpc). We combine familiar point-spread function and aperture photometry with an innovative application of image subtraction to catalog the self-obscured massive stars in these galaxies. In particular, we verify that stars analogous to the progenitors of the NGC 6946 (SN 2008S) and NGC 300 transients are truly rare in all four galaxies: their number may be as low as ~1 per galaxy at any given moment. This result empirically supports the idea that the dust-enshrouded phase is a very short lived phenomenon in the lives of many massive stars and that these objects constitute a natural extension of the asymptotic giant branch sequence. We also provide mid-IR catalogs of sources in NGC 300, M81, and NGC 6946.
- ID:
- ivo://CDS.VizieR/J/AJ/119/1214
- Title:
- Census of star clusters in the SMC
- Short Name:
- J/AJ/119/1214
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Surveys using CCD detectors are retrieving bright and faint catalogued clusters and revealing new ones in the Magellanic Clouds. This paper discusses the contribution of the OGLE Survey to the overall census of star clusters in the Small Magellanic Cloud (SMC). A detailed cross-identification indicates that the new objects in the SMC OGLE catalog are 46. The increase in the number of catalogued clusters is {~}7%, the total sample being {~}700. This updated census includes embedded clusters in H II regions and a density range attaining loose systems.
- ID:
- ivo://CDS.VizieR/J/ApJ/880/7
- Title:
- Census of the Local Universe survey. I. CLU-Halpha
- Short Name:
- J/ApJ/880/7
- Date:
- 03 Nov 2021 07:51:08
- Publisher:
- CDS
- Description:
- We present the Census of the Local Universe (CLU) narrowband survey to search for emission-line (H{alpha}) galaxies. CLU-H{alpha} has imaged ~3{pi} of the sky (26470deg^2^) with four narrowband filters that probe a distance out to 200Mpc. We have obtained spectroscopic follow-up for galaxy candidates in 14 preliminary fields (101.6deg^2^) to characterize the limits and completeness of the survey. In these preliminary fields, CLU can identify emission lines down to an H{alpha} flux limit of 10^-14^erg/s/cm^2^ at 90% completeness, and recovers 83% (67%) of the H{alpha} flux from cataloged galaxies in our search volume at the {Sigma}=2.5 ({Sigma}=5) color excess levels. The contamination from galaxies with no emission lines is 61% (12%) for {Sigma}=2.5 ({Sigma}=5). Also, in the regions of overlap between our preliminary fields and previous emission-line surveys, we recover the majority of the galaxies found in previous surveys and identify an additional ~300 galaxies. In total, we find 90 galaxies with no previous distance information, several of which are interesting objects: 7 blue compact dwarfs, 1 green pea, and a Seyfert galaxy; we also identify a known planetary nebula. These objects show that the CLU-H{alpha} survey can be a discovery machine for objects in our own Galaxy and extreme galaxies out to intermediate redshifts. However, the majority of the CLU-H{alpha} galaxies identified in this work show properties consistent with normal star-forming galaxies. CLU-H{alpha} galaxies with new redshifts will be added to existing galaxy catalogs to focus the search for the electromagnetic counterpart to gravitational wave events.
- ID:
- ivo://CDS.VizieR/J/AJ/162/52
- Title:
- Census of variable stars toward Serpens Main
- Short Name:
- J/AJ/162/52
- Date:
- 14 Mar 2022 06:55:43
- Publisher:
- CDS
- Description:
- We monitored a 3deg^2^ area toward Serpens Main in the Pan-STARRS1 r, i, and z bands from 2016 April to September. Light curves of more than 11000 stars in each band were obtained, and 143 variables have been identified. Among those, 119 variables are new discoveries, while 24 variables were previously known. We present variability classes and periods of 99 stars. Of these, 81 are located in the upper giant branch, displaying long periods, while the remaining 18 variables are pre-main-sequence objects with short periods. We also identify eight eclipsing binary systems, including the known binary V0623Ser, and derive their physical parameters. According to a clustering analysis of Gaia DR2 stars in the observed field, there are 10 variable members in Serpens Main, where six members have been classified as young stellar objects in previous studies. Here we provide color-magnitude and color-color diagrams for these variables. The color variability of most variables in the color-magnitude diagrams produces the expected displacements, while the movements of cluster members point in different directions; this behavior may be associated with accretion spots or circumstellar disks.
- ID:
- ivo://nasa.heasarc/cenacxo
- Title:
- Centaurus A Galaxy Chandra X-Ray Point Source Catalog
- Short Name:
- CENACXO
- Date:
- 02 May 2025
- Publisher:
- NASA/GSFC HEASARC
- Description:
- This table contains the results from two Chandra X-ray Observatory observations of the X-ray point source population in the nearby radio galaxy Centaurus A (NGC 5128). Using a wavelet decomposition detection algorithm, 246 individual point sources are detected above a limiting luminosity of ~ 2 * 10<sup>36</sup> ergs/s, 82 of which are detected in both data sets where the fields of view overlap. Thirty-eight sources were detected in only one observation but were within the field of view of both pointings, implying considerable variability. Eight foreground stars were identified in these observations, and nine of the sources were identified with known globular clusters in Centaurus A. All previously observed ROSAT sources within our field of view were detected. The faintest source in this table has 5 counts, which corresponds to a limiting luminosity of ~2.2 x 10<sup>36</sup> erg/s at the center of the field of view. The two observations of Cen A were made with the ACIS-I array (observation IDs were 00316 and 00962) on 1999 December 5 and 2000 May 17, with 35.9 36.5 ks exposures, respectively. This table was created by the HEASARC in February 2007 based on CDS table J/ApJ/560/675 file table2.dat. This is a service provided by NASA HEASARC .
- ID:
- ivo://CDS.VizieR/J/other/NatAs/6.109
- Title:
- Centaurus A (NGC 5128) 185MHz MWA image
- Short Name:
- J/other/NatAs/6.
- Date:
- 22 Feb 2022
- Publisher:
- CDS
- Description:
- Supermassive black holes and supernovae explosions at the centres of active galaxies power cycles of outflowing and inflowing gas that affect galactic evolution and the overall structure of theUniverse. While simulations and observations show that this must be the case, the range of physical scales (over ten orders of magnitude) and paucity of available tracers, make both the simulation and observation of these effects difficult. By serendipity, there lies an active galaxy, Centaurus A (NGC 5128), at such a close proximity as to allow its observation over this entire range of scales and across the entire electromagnetic spectrum. In the radio band, however, details on scales of 10-100kpc from the supermassive black hole have so far been obscured by instrumental limitations. Here we report low-frequency radio observations that overcome these limitations and show evidence for a broad, bipolar outflow with velocity 1100 km per s and mass outflow rate of 2.9 solar masses per year on these scales. We combine our data with the plethora of multi-scale, multi-wavelength historical observations of Centaurus A to probe a unified view of feeding and feedback, which we show to be consistent with the Chaotic Cold Accretion self-regulation scenario.
- ID:
- ivo://CDS.VizieR/J/ApJS/170/95
- Title:
- Centaurus Cluster catalog
- Short Name:
- J/ApJS/170/95
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present a catalog of all galaxies with V<=22.0 and R_iso_>3" within a 0.83deg^2^ region centered on the Centaurus Cluster (Abell 3526) at RA=12h48m, DE=-41{deg}18'. V-band total magnitudes along with other photometric parameters were obtained from the detection programs FOCAS and SExtractor and also from fitting curve-of-growth Sersic functions to the galaxy profiles. Central surface brightnesses, half-light radii, ellipticity, and position angles are presented, along with (B-V) aperture colors where B-band data were obtained. This work is part of a larger program to study the cluster-to-cluster variation in the faint end of the LF based on the study of eight clusters, including Centaurus. We discuss our data reduction methods in this paper. More detailed analyses and science results will be presented in subsequent papers.
- ID:
- ivo://CDS.VizieR/J/A+A/327/952
- Title:
- Centaurus cluster velocities
- Short Name:
- J/A+A/327/952
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Based on the photometric survey of the inner region of the Centaurus cluster (Jerjen & Dressler, 1997, Cat. <J/A+AS/124/1>) we measured redshifts for a deep, surface brightness limited sample of galaxies using the MEFOS multifibre spectrograph at the ESO 3.6m telescope. With the new data set radial velocities for 120 centrally located cluster members become available which is equivalent to 78% of all known cluster galaxies in the region brighter than B_T_=18.5. The relevant aspect of this investigation is that new redshifts for 32 dwarf galaxies have been measured, rising the total number to 48. We investigate the prominent bimodal velocity distribution of Centaurus in more detail, discussing the very different characteristics of the velocity distributions for the main Hubble types E&S0, spirals, Im&BCD, and dE&dS0. The nucleated, bright dwarf ellipticals are the only galaxies with a Gaussian-like distribution centred at 3148+/-98km/s. The remarkable coincidence of this velocity with the mean velocity of Cen 30 and the redshift of NGC 4696 in particular strongly suggests a connection of the dE&dS0s to the gravitational centre of the Centaurus cluster and/or to the cluster dominant E galaxy. The application of statistical tests reveals the existence of a population dwarf galaxies bound to NGC 4696. The dynamical parameters for the two velocity components suggest that Cen 30 is the real Centaurus cluster whereas Cen 45 can only be a loosely bound group of galaxies. This conclusion is followed up with a type-mixture analysis. All results are fully consistent with the cluster-group scenario. Whether Cen 45 is merging with the cluster or is located in the close background remains unclear. We show that the poorness of Cen 45 represents an intrinsic problem which makes it difficult to approach this question.
- ID:
- ivo://CDS.VizieR/J/A+A/472/111
- Title:
- Centaurus Compact Object Survey
- Short Name:
- J/A+A/472/111
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Our aim is to extend the investigations of ultra-compact dwarf galaxies (UCD) beyond the well studied Fornax and Virgo clusters. We measured spectroscopic redshifts of about 400 compact object candidates with 19.2<V<22.4mag in the central region of the Centaurus galaxy cluster (d=43Mpc), using 3 pointings with VIMOS@VLT. The luminosity range of the candidates covers the bright end of the globular cluster (GC) luminosity function and the luminosity regime of UCDs in Fornax and Virgo. Within the area surveyed, our completeness in terms of slit allocation is ~30%.
