Search

Start Over Capability Type Simple Cone Search
17251. VVV galaxies behind Galactic bulge overdensity
ID:
ivo://CDS.VizieR/J/A+A/646/A146
Title:
VVV galaxies behind Galactic bulge overdensity
Short Name:
J/A+A/646/A146
Date:
21 Oct 2021
Publisher:
CDS
Description:
The extragalactic vision we have through the Milky Way is very unclear. There is significant extinction of the optical emission from objects located in the region called the Zone of Avoidance (ZOA). NIR wavelengths are less affected by extinction, and therefore the infrared surveys in this zone are a potential source of astronomical discoveries. Nevertheless, these observations need to be compared with cosmological simulations in order to carry out high-accuracy studies. Our aim is to identify extragalactic sources in the ZOA, using infrared images of the VVV survey. We consider mock galaxy catalogues in order to interpret observational results. We studied a region of 1.636 square degrees corresponding to the VVV tile b204. Using SExtractor, we analysed photometric data generating a catalogue of extended sources in this area. In order to confirm these sources as galaxy candidates we visually inspected RGB images looking for typical galaxy features. Using 2MASX and GCMW catalogued sources we tested completeness and contamination of our catalogue and define suitable colour cuts to select galaxies. We also compared the observational results with those obtained from two semi-analytical models on Dark Matter simulations. One galaxy catalogue was constructed with the SAG semi-analytic model of galaxy formation, and the other one was constructed with the L-Galaxies semi-analytic model. By adopting CLASS_STAR<0.5, r1/2>0.7 arcsec and specific colour cuts (J-Ks>0.97, J-H>0 and H-Ks>0) we generated an automatic catalogue of extended sources. After visual inspection we identified 624 sources with 10<Ks<17 as galaxy candidates.The contamination of the automatic catalogue is 28% when considering visually confirmed galaxies as reliable objects. The estimated completeness is 87% up to magnitude Ks=13.5. We analysed the spatial distribution of galaxy candidates, finding a high concentration of galaxies in a small region of 15 arcmin radius. This region has three times higher density than similar areas in the tile. We compared the number of galaxies in this small area with the mean density values obtained from a suitable sample of galaxies from semi-analytic models finding that our results are consistent with an overdensity region. Using VVV near-infrared data and mock catalogues we detect new extragalactic sources that have not been identified by other catalogues. We demonstrate the potentiality of the VVV survey in finding and studying a large number of galaxy candidates and extragalactic structures obscured by the Milky Way.
17252. VVV globulars. I. 2MASS-GC 02, Terzan 10
ID:
ivo://CDS.VizieR/J/AJ/149/99
Title:
VVV globulars. I. 2MASS-GC 02, Terzan 10
Short Name:
J/AJ/149/99
Date:
21 Oct 2021
Publisher:
CDS
Description:
The VISTA Variables in the Via Lactea (VVV) ESO Public Survey is opening a new window to study inner Galactic globular clusters (GCs) using their variable stars. These GCs have been neglected in the past due to the difficulties caused by the presence of elevated extinction and high field stellar densities in their lines of sight. However, the discovery and study of any present variables in these clusters, especially RR Lyrae stars, can help to greatly improve the accuracy of their physical parameters. It can also help to shed some light on the questions raised by the intriguing Oosterhoff dichotomy in the Galactic GC system. In a series of papers we plan to explore variable stars in the GCs falling inside the field of the VVV survey. In this first paper, we search for and study the variables present in two highly reddened, moderately metal-poor, faint, inner Galactic GCs: 2MASS-GC 02 and Terzan 10. We report the discovery of sizable populations of RR Lyrae stars in both GCs. We use near-infrared period-luminosity relations to determine the color excess of each RR Lyrae star, from which we obtain both accurate distances to the GCs and the ratios of the selective-to-total extinction in their directions. We find the extinction toward both clusters to be elevated, non-standard, and highly differential. We also find both clusters to be closer to the Galactic center than previously thought, with Terzan 10 being on the far side of the Galactic bulge. Finally, we discuss their Oosterhoff properties, and conclude that both clusters stand out from the dichotomy followed by most Galactic GCs.
17253. VVV high amplitude NIR variable stars
ID:
ivo://CDS.VizieR/J/MNRAS/465/3011
Title:
VVV high amplitude NIR variable stars
Short Name:
J/MNRAS/465/3011
Date:
21 Oct 2021
Publisher:
CDS
Description:
We present the discovery of 816 high-amplitude infrared variable stars ({Delta}K_s_>1mag) in 119deg^2^ of the Galactic mid-plane covered by the VISTA Variables in the Via Lactea (VVV) survey. Almost all are new discoveries and about 50 per cent are young stellar objects (YSOs). This provides further evidence that YSOs are the commonest high-amplitude infrared variable stars in the Galactic plane. In the 2010-2014 time series of likely YSOs, we find that the amplitude of variability increases towards younger evolutionary classes (class I and flat-spectrum sources) except on short time-scales (<25d) where this trend is reversed. Dividing the likely YSOs by light-curve morphology, we find 106 with eruptive light curves, 45 dippers, 39 faders, 24 eclipsing binaries, 65 long-term periodic variables (P>100d) and 162 short-term variables. Eruptive YSOs and faders tend to have the highest amplitudes and eruptive systems have the reddest spectral energy distribution (SEDs). Follow-up spectroscopy in a companion paper verifies high accretion rates in the eruptive systems. Variable extinction is disfavoured by the two epochs of colour data. These discoveries increase the number of eruptive variable YSOs by a factor of at least 5, most being at earlier stages of evolution than the known FUor and EXor types. We find that eruptive variability is at least an order of magnitude more common in class I YSOs than class II YSOs. Typical outburst durations are 1-4yr, between those of EXors and FUors. They occur in 3-6 per cent of class I YSOs over a 4yr time span.
17254. VVV high proper motion stars. I. Ks<=13.5 stars
ID:
ivo://CDS.VizieR/J/MNRAS/464/1247
Title:
VVV high proper motion stars. I. Ks<=13.5 stars
Short Name:
J/MNRAS/464/1247
Date:
21 Oct 2021
Publisher:
CDS
Description:
Knowledge of the stellar content near the Sun is important for a broad range of topics ranging from the search for planets to the study of Milky Way (MW) structure. The most powerful method for identifying potentially nearby stars is proper motion (PM) surveys. All old optical surveys avoid, or are at least substantially incomplete, near the Galactic plane. The depth and breadth of the 'VISTA Variables in Via Lactea' (VVV) near-IR survey significantly improves this situation. Taking advantage of the VVV survey data base, we have measured PMs in the densest regions of the MW bulge and southern plane in order to complete the census of nearby objects. We have developed a custom PM pipeline based on VVV catalogues from the Cambridge Astronomy Survey Unit, by comparing the first epoch of JHKs with the multi-epoch Ks bands acquired later. Taking advantage of the large time baseline between the Two Micron All Sky Survey (2MASS) and the VVV observations, we also obtained 2MASS-VVV PMs. We present a near-IR PM catalogue for the whole area of the VVV survey, which includes 3003 moving stellar sources. All of these have been visually inspected and are real PM objects. Our catalogue is in very good agreement with the PM data supplied in IR catalogues outside the densest zone of the MW. The majority of the PM objects in our catalogue are nearby M-dwarfs, as expected. This new data base allows us to identify 57 common PM binary candidates, among which are two new systems within 30 pcof the Sun.
17255. VVV: star formation and embedded clusters
ID:
ivo://CDS.VizieR/J/A+A/562/A115
Title:
VVV: star formation and embedded clusters
Short Name:
J/A+A/562/A115
Date:
21 Oct 2021
Publisher:
CDS
Description:
We aim to locate previously unknown stellar clusters using the VISTA variables in the Via Lactea Survey (VVV) catalogue data. The method fits a mixture model of Gaussian densities and background noise and uses the expectation maximization algorithm to pre-filtered near-infrared survey stellar catalogue data; it was developed by the authors for the UKIDSS Galactic Plane Survey (GPS). The search located 88 previously unknown candidates, most of which are embedded stellar cluster candidates, and 39 previously unknown sites of star formation in the 562deg^2^ covered by VVV in the Galactic bulge and the southern disk.
17256. VVV Survey Band Merged JHKs
ID:
ivo://ar.nova/vvvsurvey/q/scs
Title:
VVV Survey Band Merged JHKs
Short Name:
NOVA VVVSurvey BM
Date:
03 Mar 2015 00:55:01
Publisher:
Nova
Description:
Band merged JHKs catalogue for first epoch data from CASU v1.3. VVV DR1, corrected for header errors (Mike Irwin, Private Communication). Release of the Milky Way bulge and southern plane from the near-infrared ESO public survey VISTA variables in the Vía Láctea.
17257. VVV survey Galactic Bulge Pop. II Cepheids
ID:
ivo://CDS.VizieR/J/A+A/605/A100
Title:
VVV survey Galactic Bulge Pop. II Cepheids
Short Name:
J/A+A/605/A100
Date:
21 Oct 2021
Publisher:
CDS
Description:
We present the near-infrared observations of population II Cepheids in the Galactic bulge from VVV survey. We identify 340 population II Cepheids in the Galactic bulge from VVV survey based on their match with OGLE-III Catalogue. The single-epoch JH and multi-epoch Ks observations complement the accurate periods and optical (VI) mean-magnitudes from OGLE. The sample consisting of BL Herculis and W Virginis subtypes is used to derive period-luminosity relations after correcting mean-magnitudes for the extinction. The absolute magnitudes for population II Cepheids and RR Lyraes calibrated using Gaia and Hubble Space Telescope parallaxes, together with calibrated magnitudes for Large Magellanic Cloud population II Cepheids, are used to obtain a distance to the Galactic center. The number density for population II Cepheids is more limited as compared to abundant RR Lyraes but they are bright and exhibit a wide range in period that provides a robust period-luminosity relation for an accurate estimate of the distance to the Galactic center.
17258. VVV survey microlensing events; -3.7<b{<}-3.9{deg}
ID:
ivo://CDS.VizieR/J/ApJ/889/56
Title:
VVV survey microlensing events; -3.7<b{<}-3.9{deg}
Short Name:
J/ApJ/889/56
Date:
17 Jan 2022 11:50:08
Publisher:
CDS
Description:
We search for microlensing events in fields along the Galactic minor axis, ranging from the Galactic center to -3.7{deg}<b<3.9{deg} using the VISTA Variables in the Via Lactea (VVV) survey near-IR photometry. The new search is made across VVV tiles b291, b305, b319, b347, b361, and b375, covering a total area of about 11.5deg^2^. We find a total of N=238 new microlensing events in this new area, N=74, which are classified as bulge red clump (RC) giant sources. Combining them with N=122 events that we had previously reported in the Galactic center (VVV tile b333), allows us to study the latitude distribution of the microlensing events reaching the Galactic plane at b=00 for the first time. We find a very strong dependence of the number of microlensing events with Galactic latitude, a number that increases rapidly toward the Galactic center by one order of magnitude from |b|=2{deg} to b=0{deg} with a much steeper gradient than with Galactic longitude. The microlensing event population shows a flattened distribution (axial ratio b/a~1.5). The final sample shows a shorter mean timescale distribution than the Galactic plane sample for both the complete population and RC stars.
17259. VVV Survey microlensing events in the Gal. Bulge
ID:
ivo://CDS.VizieR/J/ApJ/893/65
Title:
VVV Survey microlensing events in the Gal. Bulge
Short Name:
J/ApJ/893/65
Date:
19 Jan 2022 11:43:07
Publisher:
CDS
Description:
We search for microlensing events in the zero-latitude area of the Galactic Bulge using the VVV Survey near-IR data. We have discovered a total sample of N=630 events within an area covering 20.68deg^2^ between the years 2010 and 2015. In this paper, we describe the search and present the data for the final sample, including near-IR magnitudes, colors, and proper motions, as well as the standard microlensing parameters. We use the near-IR color-magnitude and color-color diagrams to select NRC=290 events with red-clump sources to analyze the extinction properties of the sample in the central region of the Galactic plane. The timescale distribution and its dependence in the longitude axis is presented. The mean timescale decreases as we approach the Galactic minor axis (b=0{deg}). Finally, we give examples of special microlensing events, such as binaries, short-timescale events, and events with a strong parallax effect.
17260. VVV survey near-infrared colour catalogue
ID:
ivo://CDS.VizieR/J/A+A/647/A169
Title:
VVV survey near-infrared colour catalogue
Short Name:
J/A+A/647/A169
Date:
21 Oct 2021
Publisher:
CDS
Description:
The Vista Variables in the Via Lactea (VVV) near-infrared (IR) variability survey explores some of the most complicated regions of the Milky Way bulge and disk in terms of high extinction and high crowding. We add a new wavelength dimension to the optical information available at the American Association of Variable Star Observers International Variable Star Index (VSX-AAVSO) catalogue to test the VVV survey near-IR photometry to better characterise these objects. We cross-match the VVV and the VSX-AAVSO catalogues along with Gaia Data Release 2 photometry and parallax. We present a catalogue that includes accurate individual coordinates, near-IR magnitudes (ZYJHKs), extinctions AKs, and distances based on Gaia parallaxes. We also show the near-IR CMDs and spatial distributions for the different VSX types of variable stars, including important distance indicators, such as RR Lyrae, Cepheids and Miras. By analysing the photometric flags in our catalogue, we found that around 20% of the stars with measured and verified variability are flagged as "non-stellar source", even when they are outside of the saturation and/or noise regimes. Additionally, we pair-matched our sample with the VIVA catalogue and found that more than half of our sources are missing from the VVV variability list, mostly due to low signal-to-noise observations or photometric problems with a small percentage due to failures in the selection process. Conclusions. Our results suggest that the current knowledge about variability in the Galaxy is biased to the nearby, low extincted stars. The present catalogue also provides the groundwork to characterise the results of future large variability surveys like the Vera C. Rubin Observatory's Legacy Survey of Space and Time in the heavily crowded and reddened regions of the Galactic plane, as wellas follow-up campaigns to characterise specific types of variables. The analysis of the miss-flagged stars can be used to improve the photometric classification of the VVV data allowing to expand the amount of data considered useful for science purposes. Besides, we provide an additional list of stars missed by the VIVA procedures for which the observations are actually good and they were missed due to some failure in the VIVA selection process.

Limit your search

more »

more »

more »

more »

more »

more »