- ID:
- ivo://CDS.VizieR/J/AJ/150/27
- Title:
- New catalog of variable stars in M37 field
- Short Name:
- J/AJ/150/27
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present a comprehensive re-analysis of stellar photometric variability in the field of the open cluster M37 following the application of a new photometry and de-trending method to the MMT/Megacam image archive. This new analysis allows a rare opportunity to explore photometric variability over a broad range of timescales, from minutes to a month. The intent of this work is to examine the entire sample of more than 30000 objects for periodic, aperiodic, and sporadic behaviors in their light curves. We show a modified version of the fast {chi}^2^ periodogram algorithm (F{chi}^2^) and change-point analysis as tools for detecting and assessing the significance of periodic and non-periodic variations. The benefits of our new photometry and analysis methods are evident. A total of 2306 stars exhibit convincing variations that are induced by flares, pulsations, eclipses, starspots, and unknown causes in some cases. This represents a 60% increase in the number of variables known in this field. Moreover, 30 of the previously identified variables are found to be false positives resulting from time-dependent systematic effects. The new catalog includes 61 eclipsing binary systems, 92 multiperiodic variable stars, 132 aperiodic variables, and 436 flare stars, as well as several hundreds of rotating variables. Based on extended and improved catalog of variables, we investigate the basic properties (e.g., period, amplitude, type) of all variables. The catalog can be accessed through the web interface (http://stardb.yonsei.ac.kr/).
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Search Results
- ID:
- ivo://CDS.VizieR/J/MNRAS/383/831
- Title:
- New DENIS nearby L and late-M dwarfs
- Short Name:
- J/MNRAS/383/831
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We report on new nearby L and late-M dwarfs (d_phot_<=30pc) discovered in our search for nearby ultracool dwarfs (I-J>=3.0, later than M8.0) in the Galactic plane (|b|<15{deg}) over 4800 deg^2^ in the Deep Near Infrared Survey of t he Southern Sky (DENIS) data base. We used late-M (>=M8.0), L and T dwarfs with accurate trigonometric parallaxes to calibrate the M_J_ versus I-J colour-luminosity relation. The resulting photometric distances have standard errors of ~15 per cent, which we used to select candidates dphot <=30pc. We measured proper motions from multi-epoch images found in the public archives ALADIN, DSS, 2MASS and DENIS, with at least three distinct epochs and time baselines of 10-21yr. We then used the Maximum Reduced Proper Motion method to select 28 candidates as ultracool dwarfs (M8.0-L8.0) and to reject one as a distant red star. Our low-resolution optical spectra confirmed that 26 were indeed ultracool dwarfs, with spectral types from M8.0 to L5.5. Two contaminants and one rejected by the maximum reduced proper motion cut-off were all reddened F-K main sequence stars. 20 of these 26 ultracool dwarfs are new nearby ultracool dwarf members, three L dwarfs within 15pc with one L3.5 at only ~10pc.
- ID:
- ivo://CDS.VizieR/J/ApJS/206/9
- Title:
- New EGOs from Spitzer GLIMPSE II survey. I.
- Short Name:
- J/ApJS/206/9
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We have produced a catalog containing 98 newly identified massive young stellar object (MYSO) candidates associated with ongoing outflows (known as extended green objects, or EGOs). These have been identified from the Spitzer Galactic Legacy Infrared Mid-Plane Survey Extraordinaire (GLIMPSE) II data set and our new identifications increase the number of known EGOs to ~400 in our Galaxy, adding to the ~300 previously identified EGOs reported by Cyganowski et al. (2008, Cat. J/AJ/136/2391) from the GLIMPSE I survey. The high detection rate (~70%) of 95 GHz class I methanol masers achieved in a survey toward 57 of these new EGOs with the Mopra 22m radio telescope demonstrates that the new EGOs are associated with outflows. Investigations of the mid-infrared properties and physical associations with other star formation tracers (e.g., infrared dark clouds, class I and II methanol masers, and millimeter Bolocam Galactic Plane Survey sources) reveal that the newly identified EGOs are very similar in nature to those in the sample of Cyganowski et al. All of the observational evidence supports the hypothesis that EGOs correspond to MYSOs at the earliest evolutionary stage, with ongoing outflow activity, and active rapid accretion.
- ID:
- ivo://CDS.VizieR/J/ApJ/735/86
- Title:
- NEWFIRM MBS: photometric catalogs
- Short Name:
- J/ApJ/735/86
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present deep near-IR (NIR) medium-bandwidth photometry over the wavelength range 1-1.8um in the All-wavelength Extended Groth strip International Survey (AEGIS) and Cosmic Evolution Survey (COSMOS) fields. The observations were carried out using the NOAO Extremely Wide-Field Infrared Imager (NEWFIRM) on the Mayall 4m Telescope on Kitt Peak as part of the NEWFIRM Medium-Band Survey (NMBS), an NOAO survey program. In this paper, we describe the full details of the observations, data reduction, and photometry for the survey. We also present a public K-selected photometric catalog, along with accurate photometric redshifts. The redshifts are computed with 37 (20) filters in the COSMOS (AEGIS) fields, combining the NIR medium-bandwidth data with existing UV (Galaxy Evolution Explorer), visible and NIR (Canada-France-Hawaii Telescope and Subaru Telescope), and mid-IR (Spitzer/IRAC) imaging. We find excellent agreement with publicly available spectroscopic redshifts, with {sigma}_z_/(1+z)~1%-2% for ~4000 galaxies at z=0-3. The NMBS catalogs contain ~13000 galaxies at z>1.5 with accurate photometric redshifts and rest-frame colors. Due to the increased spectral resolution obtained with the five NIR medium-band filters, the median 68% confidence intervals of the photometric redshifts of both quiescent and star-forming galaxies are a factor of about two times smaller when comparing catalogs with medium-band NIR photometry to NIR broadband photometry.
- ID:
- ivo://CDS.VizieR/J/A+A/532/A131
- Title:
- New Galactic star clusters in VVV survey
- Short Name:
- J/A+A/532/A131
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- VISTA Variables in the Via Lactea (VVV) is one of the six ESO Public Surveys operating on the new 4-meter Visible and Infrared Survey Telescope for Astronomy (VISTA). VVV is scanning the Milky Way bulge and an adjacent section of the disk, where star formation activity is high. One of the principal goals of the VVV Survey is to find new star clusters of different ages. In order to trace the early epochs of star cluster formation we concentrated our search in the directions to those of known star formation regions, masers, radio, and infrared sources. The disk area covered by VVV was visually inspected using the pipeline processed and calibrated KS-band tile images for stellar overdensities. Subsequently, we examined the composite JHKS and ZJKS color images of each candidate. PSF photometry of 15x15arcmin fields centered on the candidates was then performed on the Cambridge Astronomy Survey Unit reduced images. After statistical field-star decontamination, color-magnitude and color-color diagrams were constructed and analyzed.
- ID:
- ivo://CDS.VizieR/J/AJ/129/413
- Title:
- New high proper motion stars (-90<DE< -47)
- Short Name:
- J/AJ/129/413
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We report the discovery of 141 new high proper motion systems ({mu}>=0.4"/yr) in the southern sky (DE=-90 to -47{deg}) brighter than UKST plate R_59F_=16.5 via our SuperCOSMOS-RECONS search. When combined with the nine systems having {mu}>=1.0"/yr and/or late spectral type from the initial phases of this effort, we find that 73 of the 150 total systems are moving faster than 0.5"/yr and are therefore new members of the classic Luyten Half-Second sample. These constitute a 21% increase in the sample of stars with {mu}>=0.5"/yr in the declination region searched, thereby comprising an important addition to this long-neglected region of the sky. Distance estimates are provided for the entire sample, based on a combination of photographic plate magnitudes and Two Micron All Sky Survey photometry, using the relations recently presented by Hambly et al. for the presumed main-sequence stars. Three systems are anticipated to be within 10pc, and an additional 15 are within 25pc. Nine of these 18 nearby systems have proper motions falling between 0.4"/yr and 0.6"/yr, hinting at a large population of nearby stars with fast, but not extremely high, proper motions that have not been thoroughly investigated.
- ID:
- ivo://CDS.VizieR/J/AJ/130/1658
- Title:
- New high proper motion stars (-47<{delta}<00)
- Short Name:
- J/AJ/130/1658
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We report the discovery of 152 new high proper motion systems ({mu}>=0.4"/yr) in the southern sky ({delta}=-47{deg} to 00{deg}) brighter than UKST plate R_59F_=16.5 via our SuperCOSMOS-RECONS (SCR) search. This paper complements Paper XII (2005, Cat. <J/AJ/129/413>) in the Solar Neighborhood series, which covered the region from {delta}=-90{deg} to -47{deg} and discussed all 147 new systems from the southernmost phase of the search. Among the total of 299 systems from both papers, there are 148 (71 in Paper XII (2005, Cat. <J/AJ/129/413>), 77 in this paper) new systems moving faster than 0.5"/yr that are additions to the classic Luyten Half Second sample (1979, Cat. <I/87>). These constitute an 8% increase in the sample of all stellar systems with {mu}>=0.5"/yr in the southern sky.
1518. New hot subdwarf stars
- ID:
- ivo://CDS.VizieR/J/MNRAS/457/3396
- Title:
- New hot subdwarf stars
- Short Name:
- J/MNRAS/457/3396
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Recent massive sky surveys in different bandwidths are providing new opportunities to modern astronomy. The Virtual Observatory (VO) represents the adequate framework to handle the huge amount of information available and filter out data according to specific requirements. In this work, we applied a selection strategy to find new, uncatalogued hot subdwarfs making use of VO tools. We used large area catalogues like GALEX, Sloan Digital Sky Survey (SDSS), SuperCosmos and Two Micron All Sky Survey (2MASS) to retrieve photometric and astrometric information of stellar objects. To these objects, we applied colour and proper motion filters, together with an effective temperature cutoff, aimed at separating hot subdwarfs from other blue objects such as white dwarfs, cataclysmic variables or main-sequence OB stars. As a result, we obtained 437 new, uncatalogued hot subdwarf candidates. Based on previous results, we expect our procedure to have an overall efficiency of at least 80 per cent. Visual inspection of the 68 candidates with SDSS spectrum showed that 65 can be classified as hot subdwarfs: 5 sdOs, 25 sdOBs and 35 sdBs. This success rate above 95 per cent proves the robustness and efficiency of our methodology. The spectral energy distribution of 45 per cent of the subdwarf candidates showed infrared excesses, a signature of their probable binary nature. The stellar companions of the binary systems so detected are expected to be late-type main-sequence stars. A detailed determination of temperatures and spectral classification of the cool companions will be presented in a forthcoming work.
- ID:
- ivo://CDS.VizieR/J/A+AS/122/489
- Title:
- New infrared carbon stars in IRAS PSC
- Short Name:
- J/A+AS/122/489
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present new results of a search for infrared carbon stars (IRCS) based on the combination of IRAS and near infrared colours. A sample of 207 stars with IRAS colours that characterize IRCS is selected and measured in the JHKL photometric bands. Using a [12-25] vs. K-L colour diagram, 20 new IRCS candidates are proposed. Medium resolution spectra in the ~6000-9000{AA} range of 8 of these candidates confirm their carbon rich nature. In addition we propose a few stars with LRS class "4n" as oxygen-rich candidates, and a few stars with LRS classes "0n" and "1n" as carbon-rich.
- ID:
- ivo://CDS.VizieR/J/AJ/153/218
- Title:
- New IR photometric study of Ap and Am stars
- Short Name:
- J/AJ/153/218
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- In this paper, 426 well known confirmed Ap and Am stars are photometrically studied in the infrared. The 2MASS, Wide-field Infrared Survey Explorer (WISE), and IRAS data are employed to make analyses. The results in this paper have shown that in the 1-3 {mu}m region over 90% Ap and Am stars have no or little infrared excesses, and infrared radiations in the near-infrared from these stars are probably dominated by the free-free emissions. It is also shown that in the 3-12 {mu}m region, the majority of Ap stars and Am stars have very similar behavior, i.e., in the W1-W2 (3.4-4.6 {mu}m) region, over half of Ap and Am stars have clear infrared excesses, which are possibly due to the binarity, the multiplicity, and/or the debris disk, but in the W2-W3 (4.6-12 {mu}m) region they have no or little infrared excess. In addition, in the 12-22 {mu}m region, some of Ap stars and Am stars show the infrared excesses and infrared radiations for these Ap and Am stars are probably due to the free-free emissions. In addition, it is seen that the probability of being the binarity, the multiplicity and/or the debris disk for Am stars is much higher than that for Ap stars. Furthermore, it can be seen that, in general, no relations can be found between infrared colors and spectral types either for Ap stars or for Am stars.
