- ID:
- ivo://CDS.VizieR/J/AJ/123/2822
- Title:
- Photometry of southern NLTT stars
- Short Name:
- J/AJ/123/2822
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present BVRI photometry of 180 bright, southern nearby-star candidates. The stars were selected from the New Luyten Two-Tenths proper-motion catalog (Cat. <I/98>) based on optical/infrared colors, constructed by combining Luyten's m_r_ estimates with near-infrared photometry from the Two Micron All Sky Survey (Cat. <B/2mass>) . Photometric parallaxes derived from V-Ks, V-I, and I-J colors, combined with the limited available astrometry, show that as many as 108 stars may lie within 20pc of the Sun. Of these, 53 are new to nearby-star catalogs, including three within 10pc of the Sun.
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- ID:
- ivo://CDS.VizieR/J/A+A/467/1003
- Title:
- Photometry of star clusters in NGC 1380
- Short Name:
- J/A+A/467/1003
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- NGC 1380 is a lenticular galaxy located near the center of the Fornax Cluster, northeast of NGC 1399. The globular cluster system of this galaxy was previously studied only from the ground. Recent studies of similar early-type galaxies, specially lenticular ones, reveal the existence of star clusters that apparently break up the traditional open/globular cluster dichotomy. With higher quality photometry from HST/WFPC2 we study the star clusters in NGC 1380, measuring their magnitudes, colours, sizes and projected distances from the center of the galaxy. We used deep archival HST/WFPC2 in the B and V bands. We built colour magnitude diagrams from which we selected a sample of cluster candidates. We also analysed their colour distribution and measured their sizes. Based on their location in the luminosity-size diagram we estimated probabilities of them being typical globular clusters as those found in the Galaxy. A total of about 570 cluster candidates were found down to V=26.5. We measured sizes for approximately 200 of them. The observed colour distribution has three apparent peaks. Likewise for the size distribution. We identified the smaller population as being mainly typical globular clusters, while the more extended objects have small probabilities of being such objects. Different correlations between absolute magnitudes, sizes, colours and location were inferred for these cluster sub-populations. Most extended clusters (Reff>4pc) share similar properties to the diffuse star clusters reported to inhabit luminous early-type galaxies in the Virgo galaxy cluster such as being of low surface brightness and fainter than MV~-8. We also report on a small group of (R_eff_~10pc), -8<MV<-6, red clusters located near the centre of NGC 1380, which may be interpreted as faint fuzzies.
- ID:
- ivo://CDS.VizieR/J/AJ/151/58
- Title:
- Photometry of stars at NAOR and ASV in 2013-2014
- Short Name:
- J/AJ/151/58
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Using the 2m telescope of the Bulgarian National Astronomical Observatory at Rozhen, observations of 271 double or multiple stars were carried out during seven nights in 2013 and 2014. This is the eighth series of measurements of CCD frames of double and multiple stars obtained at Rozhen. Also in 2013 and 2014, using the 0.6m telescope of the Serbian Astronomical Station on the mountain of Vidojevica, observations of 343 double or multiple stars were carried out during 21 nights. This is the third series of measurements of CCD frames of double and multiple stars obtained at this station. In this paper, we present the results for the position angle and angular separation for 721 pairs and residuals for 126 pairs with published orbital elements or linear solutions. These observations have angular separations in the range from 1.24'' to 202.30'', with a median angular separation of 7.17''. We also present eight linear solutions that have been calculated for the first time.
- ID:
- ivo://CDS.VizieR/J/AJ/158/215
- Title:
- Photometry of stars at NAOR and ASV in 2017-2018
- Short Name:
- J/AJ/158/215
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We give the results of CCD observations for 789 double or multiple stars obtained during 2017 and 2018. These observations were carried out at both the Serbian Astronomical Station on the mountain of Vidojevica (ASV) and the Bulgarian National Astronomical Observatory at Rozhen (NAOR). They were performed using three telescopes, the 1.4 and 0.6 m telescopes at ASV, and the 2 m telescope at NAOR. The total of 1196 measurements (position angle and angular separation) for the 939 pairs is presented. Out of this number, 55 pairs have calculated orbital or linear elements and for them the residuals are given. Some pairs have measurements for several epochs. Measured angular separations are in the interval from 1.51" to 208.81", with a median separation of 4.16". Two new pairs and linear elements for three pairs, which are calculated for the first time, are also presented.
- ID:
- ivo://CDS.VizieR/J/ApJ/812/133
- Title:
- 1889-2015 photometry of Stingray nebula
- Short Name:
- J/ApJ/812/133
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Up until around 1980, the Stingray was an ordinary B1 post-AGB star, but then it suddenly sprouted bright emission lines like in a planetary nebula (PN), and soon after this the Hubble Space Telescope (HST) discovered a small PN around the star, so apparently we have caught a star in the act of ionizing a PN. We report here on a well-sampled light curve from 1889 to 2015, with unique coverage of the prior century plus the entire duration of the PN formation plus three decades of its aftermath. Surprisingly, the star anticipated the 1980s ionization event by declining from B=10.30 in 1889 to B=10.76 in 1980. Starting in 1980, the central star faded fast, at a rate of 0.20mag/yr, reaching B=14.64 in 1996. This fast fading is apparently caused by the central star shrinking in size. From 1994 to 2015, the V-band light curve is almost entirely from the flux of two bright [OIII] emission lines from the unresolved nebula, and it shows a consistent decline at a rate of 0.090mag/yr. This steady fading (also seen in the radio and infrared) has a timescale equal to that expected for ordinary recombination within the nebula, immediately after a short-duration ionizing event in the 1980s. We are providing the first direct measure of the rapidly changing luminosity of the central star on both sides of a presumed thermal pulse in 1980, with this providing a strong and critical set of constraints, and these are found to sharply disagree with theoretical models of PN evolution.
- ID:
- ivo://CDS.VizieR/II/45
- Title:
- Photometry of strong CN stars
- Short Name:
- II/45
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- A group of 185 late G and K giants, selected from the US Naval Observatory Catalog of Photoelectric Observations (Cat. II/4) because they had Ultraviolet deficiences, were observed with the intermediate band photometric system of the David Dunlap Observatory (defined by McClure and van den Bergh 1968AJ.....73..313M). The DDO photometry is included in Cat. II/17.
- ID:
- ivo://CDS.VizieR/J/A+A/359/597
- Title:
- Photometry of SX Phe stars in globular clusters
- Short Name:
- J/A+A/359/597
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present for the first time a catalogue of SX Phe-type pulsating variables in globular clusters. In addition, SX Phe variables discovered in the Carina dwarf galaxy and other ones probably belonging to the Sagittarius dwarf galaxy are included. This catalogue is intended to be an up-dated list of all the SX Phe stars, in globular clusters and galaxies, known until now, covering information published up to January, 2000. In summary, 149 variables are presented in our list for SX Phe-type variables belonging to 18 globular clusters and 2 galaxies. Some relevant distributions are also shown. The analysis of metal abundances and mean periods shows that both parameters are correlated in the sense that the periods of the variables are longer as the metallicity of the stellar system is higher.
- ID:
- ivo://CDS.VizieR/J/MNRAS/455/1027
- Title:
- Photometry of the afterglow of GRB 130831A
- Short Name:
- J/MNRAS/455/1027
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Gamma-ray bursts (GRBs) are the most luminous explosions in the Universe, yet the nature and physical properties of their energy sources are far from understood. Very important clues, however, can be inferred by studying the afterglows of these events. We present optical and X-ray observations of GRB 130831A obtained by Swift, Chandra, Skynet, Reionization And Transients Infra-Red camera, Maidanak, International Scientific Optical-Observation Network, Nordic Optical Telescope, Liverpool Telescope and Gran Telescopio Canarias. This burst shows a steep drop in the X-ray light curve at ~10^5^ s after the trigger, with a power-law decay index of {alpha}~6. Such a rare behaviour cannot be explained by the standard forward shock (FS) model and indicates that the emission, up to the fast decay at 10^5^ s, must be of "internal origin", produced by a dissipation process within an ultrarelativistic outflow. We propose that the source of such an outflow, which must produce the X-ray flux for ~1 d in the cosmological rest frame, is a newly born magnetar or black hole. After the drop, the faint X-ray afterglow continues with a much shallower decay. The optical emission, on the other hand, shows no break across the X-ray steep decrease, and the late-time decays of both the X-ray and optical are consistent. Using both the X-ray and optical data, we show that the emission after ~10^5^ s can be explained well by the FS model. We model our data to derive the kinetic energy of the ejecta and thus measure the efficiency of the central engine of a GRB with emission of internal origin visible for a long time. Furthermore, we break down the energy budget of this GRB into the prompt emission, the late internal dissipation, the kinetic energy of the relativistic ejecta, and compare it with the energy of the associated supernova, SN 2013 fu.
- ID:
- ivo://CDS.VizieR/J/ApJS/192/12
- Title:
- Photometry of the blazar PKS 0537-441
- Short Name:
- J/ApJS/192/12
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present a large collection of photometric data on the blazar PKS 0537-441 in the VRIJHK bands taken in 2004-2009. At least three flare-like episodes with months duration and >3mag amplitude are apparent. The spectral energy distribution is consistent with a power law, and no indication of a thermal component is found. We searched for short timescale variability, and an interesting event was identified in the J band, with a duration of ~25 minutes.
- ID:
- ivo://CDS.VizieR/J/PAZh/22/764
- Title:
- Photometry of the globular cluster NGC 6139
- Short Name:
- J/PAZh/22/764
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Photographic BV photometry has been performed for stars in the southern globular cluster NGC 6139. Equatorial coordinates have been determined for the ten variables recognized in NGC 6139.
