- ID:
- ivo://CDS.VizieR/J/AJ/125/1383
- Title:
- Stromgren photometry of NGC 6253
- Short Name:
- J/AJ/125/1383
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- CCD photometry on the intermediate-band uvbyCaH system is presented for the old open cluster NGC 6253. Despite a high level of field star contamination because of its location toward the Galactic center, combination of the data from the multiple color indices with the core cluster sample derived from radial star counts leads to the identification of a set of highly probable, single cluster members.
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Search Results
- ID:
- ivo://CDS.VizieR/J/AJ/131/461
- Title:
- Stromgren photometry of NGC 2420
- Short Name:
- J/AJ/131/461
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- CCD photometry on the intermediate-band vbyCaH{beta} system is presented for the metal-deficient open cluster NGC 2420. Restricting the data to probable single members of the cluster using the CMD and the photometric indices alone generates a sample of 106 stars at the cluster turnoff.
- ID:
- ivo://CDS.VizieR/J/A+A/545/A119
- Title:
- Stromgren v photometry of {sigma} Lup
- Short Name:
- J/A+A/545/A119
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Magnetic early B-type stars are rare. Indirect indicators are needed to identify them before investing in time-intensive spectropolarimetric observations. We use the strongest indirect indicator of a magnetic field in B stars, which is periodic variability of ultraviolet (UV) stellar wind lines occurring symmetric about the approximate rest wavelength. Our aim is to identify probable magnetic candidates which would become targets for follow-up spectropolarimetry to search for a magnetic field. From the UV wind line variability the B1/B2V star sigma Lupi emerged as a new magnetic candidate star. AAT spectropolarimetric measurements with SEMPOL were obtained. The longitudinal component of the magnetic field integrated over the visible surface of the star was determined with the least- squares deconvolution method. The UV line variations of sigma Lupi are similar to what is known in magnetic B stars, but no periodicity could be determined. We detected a varying longitudinal magnetic field with amplitude of about 100G with error bars of typically 20G, which supports an oblique magnetic-rotator configuration. The equivalent width variations of the UV lines, the magnetic and the optical-line variations are consistent with the photometric period of 3.02d, which we identify with the rotation period of the star. Additional observations with ESPaDOnS attached to the CFHT confirmed this discovery, and allowed the determination of a precise magnetic period. Analysis revealed that sigma Lupi is a helium-strong star, with an enhanced nitrogen abundance and an underabundance of carbon, and has a chemically spotted surface. Conclusions. sigma Lupi is a magnetic oblique rotator, and is a He-strong star. Like in other magnetic B stars the UV wind emission appears to originate close to the magnetic equatorial plane, with maximum emission occurring when a magnetic pole points towards the Earth. The 3.01972+/-0.00043d magnetic rotation period is consistent with the photometric period, with maximum light corresponding to maximum magnetic field.
- ID:
- ivo://CDS.VizieR/J/ApJ/757/22
- Title:
- Strong and weak lensing analysis of A2261
- Short Name:
- J/ApJ/757/22
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We precisely constrain the inner mass profile of A2261 (z=0.225) for the first time and determine that this cluster is not "overconcentrated" as found previously, implying a formation time in agreement with {Lambda}CDM expectations. These results are based on multiple strong-lensing analyses of new 16-band Hubble Space Telescope imaging obtained as part of the Cluster Lensing and Supernova survey with Hubble (CLASH; Postman et al. 2012, Cat. J/ApJS/199/25). Combining this with revised weak-lensing analyses of Subaru wide-field imaging with five-band Subaru + KPNO photometry, we place tight new constraints on the halo virial mass M_vir_=(2.2+/-0.2)x10^15^M_{sun}_h^-1^_70_ (within r_vir_{approx}3Mpc.h^-1^_70_) and concentration c_vir_=6.2+/-0.3 when assuming a spherical halo. This agrees broadly with average c(M, z) predictions from recent {Lambda}CDM simulations, which span 5<~<c><~8. Our most significant systematic uncertainty is halo elongation along the line of sight (LOS). To estimate this, we also derive a mass profile based on archival Chandra X-ray observations and find it to be ~35% lower than our lensing-derived profile at r_2500_~600kpc. Agreement can be achieved by a halo elongated with a ~2:1 axis ratio along our LOS. For this elongated halo model, we find M_vir_=(1.7+/-0.2)x10^15^M_{sun}_h^-1^_70_ and c_vir_=4.6+/-0.2, placing rough lower limits on these values. The need for halo elongation can be partially obviated by non-thermal pressure support and, perhaps entirely, by systematic errors in the X-ray mass measurements. We estimate the effect of background structures based on MMT/Hectospec spectroscopic redshifts and find that these tend to lower M_vir_ further by ~7% and increase c_vir_by ~5%.
18175. Strong cyanogen stars
- ID:
- ivo://CDS.VizieR/II/46
- Title:
- Strong cyanogen stars
- Short Name:
- II/46
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- A cyanogen index for late-type giants, insensitive to surface gravity but sensitive to metallicity, is presented in the David Dunlap Observatory (DDO) photometric system. Observations were made using conventional single-channel photometers with 1P21 photomultiplier tubes on the 40cm and 90cm telescopes of Kitt Peak National Observatory. The original DDO filter set C was used (see Paper I, 1968AJ.....73..313M). Table 1 contains DDO photometry on 52 bright late-type giants for calibration. Most G8 to M0 stars, luminosity class III, V<4.0mag, north of {delta}=-10{deg}, supplement the original stars from Paper I. Table 4 includes both DDO and UBV photometry for stars from Schmitt (1967 thesis, Univ. Michigan, Ann Arbor) and Spinrad and Taylor (1967AJ.....72S.320S). Reddening values were computed using the method of McClure and Racine (1969AJ.....74.1000M).
- ID:
- ivo://CDS.VizieR/J/ApJS/243/17
- Title:
- Strong DES lens candidates from neural networks
- Short Name:
- J/ApJS/243/17
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We search Dark Energy Survey (DES) Year 3 imaging for galaxy-galaxy strong gravitational lenses using convolutional neural networks, extending previous work with new training sets and covering a wider range of redshifts and colors. We train two neural networks using images of simulated lenses, then use them to score postage-stamp images of 7.9 million sources from DES chosen to have plausible lens colors based on simulations. We examine 1175 of the highest-scored candidates and identify 152 probable or definite lenses. Examining an additional 20000 images with lower scores, we identify a further 247 probable or definite candidates. After including 86 candidates discovered in earlier searches using neural networks and 26 candidates discovered through visual inspection of blue-near-red objects in the DES catalog, we present a catalog of 511 lens candidates.
- ID:
- ivo://CDS.VizieR/J/other/Ser/178.65
- Title:
- Strongest radio point sources in LMC field
- Short Name:
- J/other/Ser/178.
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the 100 strongest 1.4GHz point sources from a new mosaic image in the direction of the Large Magellanic Cloud (LMC). The observations making up the mosaic were made using Australia Telescope Compact Array (ATCA) over a ten year period and were combined with Parkes single dish data at 1.4GHz to complete the image for short spacing. An initial list of co-identifications within 1000 at 0.843, 4.8 and 8.6GHz consisted of 2682 sources. Elimination of extended objects and artifact noise allowed the creation of a refined list containing 1988 point sources.
- ID:
- ivo://CDS.VizieR/J/A+A/654/A135
- Title:
- 12 strong galactic bars CO spectra
- Short Name:
- J/A+A/654/A135
- Date:
- 22 Feb 2022
- Publisher:
- CDS
- Description:
- While some galactic bars show recent massive star formation (SF) along them, some others present a lack of it. Whether bars with low level of SF are a consequence of low star formation efficiency, low gas inflow rate, or dynamical effects, remains a matter of debate. In order to study the physical conditions that enable or prevent SF, we perform a multi-wavelength analysis of 12 strongly barred galaxies with total stellar masses log10(M*/M_{sun}_){in}[10.2,11], chosen to host different degrees of SF along the bar major axis without any prior condition on gas content. We observe the CO(1-0) and CO(2-1) emission within bars with the IRAM-30m telescope (beam sizes of 1.7-3.9kpc and 0.9-2.0kpc, respectively; 7-8 pointings per galaxy on average). We estimate molecular gas masses (Mmol) from the CO(1-0) and CO(2-1) emissions. SF rates (SFR) are calculated from GALEX near-ultraviolet (UV) and WISE 12um images within the beam-pointings, covering the full bar extent (SFRs are also derived from far-UV and 22um). Results. We detect molecular gas along the bars of all probed galaxies. Molecular gas and SFR surface densities span the ranges log10({Sigma}_mol_/[M_{sun}_/pc^2^]){in}[0.4,2.4] and log10({Sigma}_SFR_/[M_{sun}_/pc/kpc^2^]){in}[-3.25,-0.75], respectively. The star formation efficiency (SFE=SFR/Mmol) in bars varies between galaxies by up to an order of magnitude (SFE{in}[0.1,1.8]Gyr^-1^). On average, SFEs are roughly constant along bars. SFEs are not significantly different from the mean value in spiral galaxies reported in the literature (~0.43Gyr^-1^), regardless of whether we estimate Mmol from CO(1-0) or CO(2-1). Interestingly, the higher the total stellar mass of the host galaxy, the lower the SFE within their bars. In particular, the two galaxies in our sample with lowest SFE and {Sigma}_SFR_ (NGC 4548 and NGC 5850, SFE<=0.25Gyr^-1^, {Sigma}_SFR_<=10^-2.25^M_{sun}_/yr/kpc^2^, M*<=10^10.7^M_{sun}_) are also the ones hosting massive bulges and signs of past interactions with nearby companions. We present a statistical analysis of the SFE in bars for a sample of 12 galaxies. The SFE in strong bars is not systematically inhibited (either in the central, mid- or end-parts of the bar). Both environmental and internal quenching are likely responsible for the lowest SFEs reported in this work.
- ID:
- ivo://CDS.VizieR/J/other/RAA/20.2
- Title:
- Strong galaxy-galaxy lensing in SDSS-III BOSS
- Short Name:
- J/other/RAA/20.2
- Date:
- 03 Dec 2021 00:49:25
- Publisher:
- CDS
- Description:
- Strong lensing is one of the most spectacular views in the universe. Many cosmological applications have been proposed, but the number of such lensing systems is still limited. In this work, we applied an improved version of a previously developed spectroscopic lensing search method to the SDSS-III BOSS and proposed a list of highly possible candidates. Follow-up CFHT Megacam imaging observations were performed for five systems, and two out of five are probably strong lensing systems with at least one image close to the central galaxy, although no counter images are detected.
- ID:
- ivo://CDS.VizieR/J/ApJ/894/78
- Title:
- Strong gravitational lenses from DECaLS
- Short Name:
- J/ApJ/894/78
- Date:
- 03 Dec 2021 00:50:48
- Publisher:
- CDS
- Description:
- We perform a semi-automated search for strong gravitational lensing systems in the 9000 deg2 Dark Energy Camera Legacy Survey (DECaLS), part of the Dark Energy Spectroscopic Instrument Legacy Imaging Surveys. The combination of the depth and breadth of these surveys are unparalleled at this time, making them particularly suitable for discovering new strong gravitational lensing systems. We adopt the deep residual neural network architecture developed by Lanusse+ (2018MNRAS.473.3895L) for the purpose of finding strong lenses in photometric surveys. We compile a training sample that consists of known lensing systems in the Legacy Surveys and the Dark Energy Survey as well as non-lenses in the footprint of DECaLS. In this paper we show the results of applying our trained neural network to the cutout images centered on galaxies typed as ellipticals in DECaLS. The images that receive the highest scores (probabilities) are visually inspected and ranked. Here we present 335 candidate strong lensing systems, identified for the first time.