- ID:
- ivo://CDS.VizieR/J/ApJS/227/20
- Title:
- Rotation periods of asteroids using iPTF
- Short Name:
- J/ApJS/227/20
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- In order to look for large super-fast rotators, in late 2014 and early 2015, five dedicated surveys covering ~188deg^2^ in the ecliptic plane have been carried out in the R-band, with ~10min cadence using the intermediate Palomar Transient Factory. Among 1029 reliable rotation periods obtained from the surveys, we discovered 1 new large super-fast rotator, (40511) 1999 RE88, and 18 other candidates. (40511) 1999 RE88 is an S-type inner main-belt asteroid with a diameter of D=1.9+/-0.3km, a rotation period of P=1.96+/-0.01hr, and a light curve amplitude of {Delta}m~1.0mag. To maintain such fast rotation, an internal cohesive strength of ~780Pa is required. Combining all known large super-fast rotators, their cohesive strengths all fall in the range of 100-1000Pa of lunar regolith. However, the number of large super-fast rotators seems to be far less than the whole asteroid population. This might indicate a peculiar asteroid group for them. Although the detection efficiency for a long rotation period is greatly reduced due to our two-day observation time span, the spin-rate distributions of this work show consistent results with Chang+ (2015, J/ApJS/219/27), after considering the possible observational bias in our surveys. It shows a number decrease with an increase of spin rate for asteroids with a diameter of 3<=D<=15km, and a number drop at a spin rate of f=5rev/day for asteroids with D<=3km.
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Search Results
- ID:
- ivo://CDS.VizieR/J/AJ/119/1901
- Title:
- ROTSE all-sky surveys for variable stars
- Short Name:
- J/AJ/119/1901
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The Robotic Optical Transient Search Experiment I (ROTSE-I) experiment has generated CCD photometry for the entire northern sky in two epochs nightly since 1998 March. These sky patrol data are a powerful resource for studies of astrophysical transients. As a demonstration project, we present first results of a search for periodic variable stars derived from ROTSE-I observations. Variable identification, period determination, and type classification are conducted via automatic algorithms. In a set of nine ROTSE-I sky patrol fields covering roughly 2000 deg^2^, we identify 1781 periodic variable stars with mean magnitudes between m_v_ = 10.0 and m_v_ = 15.5. About 90% of these objects are newly identified as variable. Examples of many familiar types are presented. All classifications for this study have been manually confirmed. The selection criteria for this analysis have been conservatively defined and are known to be biased against some variable classes. This preliminary study includes only 5.6% of the total ROTSE-I sky coverage, suggesting that the full ROTSE-I variable catalog will include more than 32,000 periodic variable stars.
- ID:
- ivo://CDS.VizieR/J/ApJ/831/165
- Title:
- RR Lyrae as tracers in the Virgo overdensity region
- Short Name:
- J/ApJ/831/165
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We use a combination of spatial distribution and radial velocity to search for halo substructures in a sample of 412 RR Lyrae stars (RRLSs) that covers a region of ~525 square degrees of the Virgo overdensity (VOD) and spans distances from the Sun from 4 to 75kpc. With a friends-of-friends algorithm we identified six high-significance groups of RRLSs in phase space, which we associate mainly with the VOD and with the Sagittarius stream. Four other groups were also flagged as less significant overdensities. Three high-significance and three lower-significance groups have distances between ~10 and 20kpc, which places them in the distance range attributed by others to the VOD. The largest of these is the Virgo stellar stream at 19kpc, which has 18 RRLSs, a factor of two increase over the number known previously. While these VOD groups are distinct according to our selection criteria, their overlap in position and distance and, in a few cases, similarity in radial velocity are suggestive that they may not all stem from separate accretion events. Even so, the VOD appears to be caused by more than one overdensity. The Sagittarius (Sgr) stream is a very obvious feature in the background of the VOD at a mean distance of 44kpc. Two additional high-significance groups were detected at distances >40kpc. Their radial velocities and locations differ from the expected path of the Sgr debris in this part of the sky, and they are likely to be remnants of other accretion events.
- ID:
- ivo://CDS.VizieR/J/AJ/132/1202
- Title:
- RR Lyrae in Northern Sky Variability Survey
- Short Name:
- J/AJ/132/1202
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We use data from the Northern Sky Variability Survey (NSVS), obtained from the first-generation Robotic Optical Transient Search Experiment (ROTSE-I), to identify and study RR Lyrae variable stars in the solar neighborhood. We initially identified 1197 RRab (RR0) candidate stars brighter than the ROTSE median magnitude V=14. Periods, amplitudes, and mean V magnitudes are determined for a subset of 1188 RRab stars with well-defined light curves. Metallicities are determined for 589 stars by the Fourier parameter method and by the relationship between period, amplitude, and [Fe/H]. We comment on the difficulties of clearly classifying RRc (RR1) variables in the NSVS data set. Distances to the RRab stars are calculated using an adopted luminosity-metallicity relation with corrections for interstellar extinction. The 589 RRab stars in our final sample are used to study the properties of the RRab population within 5kpc of the Sun. The Bailey diagram of period versus amplitude shows that the largest component of this sample belongs to Oosterhoff type I. Metal-rich ([Fe/H]>-1) RRab stars appear to be associated with the Galactic disk. Our metal-rich RRab sample may include a thin-disk, as well as a thick-disk population, although the uncertainties are too large to establish this. There is some evidence among the metal-rich RRab stars for a decline in scale height with increasing [Fe/H], as was found by Layden. The distribution of RRab stars with -1<[Fe/H]<-1.25 indicates that within this metallicity range the RRab stars are a mixture of stars belonging to halo and disk populations.
- ID:
- ivo://CDS.VizieR/J/MNRAS/424/2528
- Title:
- RR Lyrae in SDSS Stripe 82
- Short Name:
- J/MNRAS/424/2528
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We propose a robust principal component analysis framework for the exploitation of multiband photometric measurements in large surveys. Period search results are improved using the time-series of the first principal component due to its optimized signal-to-noise ratio. The presence of correlated excess variations in the multivariate time-series enables the detection of weaker variability. Furthermore, the direction of the largest variance differs for certain types of variable stars. This can be used as an efficient attribute for classification. The application of the method to a subsample of Sloan Digital Sky Survey Stripe 82 data yielded 132 high-amplitude delta Scuti variables. We also found 129 new RR Lyrae variables, complementary to the catalogue of Sesar et al., extending the halo area mapped by Stripe 82 RR Lyrae stars towards the Galactic bulge. The sample also comprises 25 multiperiodic or Blazhko RR Lyrae stars.
- ID:
- ivo://CDS.VizieR/J/AJ/153/204
- Title:
- RR Lyrae stars from the PS1 3{pi} survey
- Short Name:
- J/AJ/153/204
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- RR Lyrae stars may be the best practical tracers of Galactic halo (sub-)structure and kinematics. The PanSTARRS1 (PS1) 3{pi} survey offers multi-band, multi-epoch, precise photometry across much of the sky, but a robust identification of RR Lyrae stars in this data set poses a challenge, given PS1's sparse, asynchronous multi-band light curves (<~12 epochs in each of five bands, taken over a 4.5yr period). We present a novel template fitting technique that uses well-defined and physically motivated multi-band light curves of RR Lyrae stars, and demonstrate that we get accurate period estimates, precise to 2s in >80% of cases. We augment these light-curve fits with other features from photometric time-series and provide them to progressively more detailed machine-learned classification models. From these models, we are able to select the widest (three-fourths of the sky) and deepest (reaching 120kpc) sample of RR Lyrae stars to date. The PS1 sample of ~45000 RRab stars is pure (90%) and complete (80% at 80kpc) at high galactic latitudes. It also provides distances that are precise to 3%, measured with newly derived period-luminosity relations for optical/near-infrared PS1 bands. With the addition of proper motions from Gaia and radial velocity measurements from multi-object spectroscopic surveys, we expect the PS1 sample of RR Lyrae stars to become the premier source for studying the structure, kinematics, and the gravitational potential of the Galactic halo. The techniques presented in this study should translate well to other sparse, multi-band data sets, such as those produced by the Dark Energy Survey and the upcoming Large Synoptic Survey Telescope Galactic plane sub-survey.
- ID:
- ivo://CDS.VizieR/J/other/IBVS/6106
- Title:
- RR Lyrae stars in GCVS observed by the QES
- Short Name:
- J/other/IBVS/610
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We used the light curve archive of the Qatar Exoplanet Survey to investigate the RR Lyrae variable stars listed in the GCVS. Of 588 variables studied, we reclassified 14 as eclipsing binaries, one as an RS CVn type variable, one as an irregular variable, four as classical Cepheids, and one as a type II Cepheid, while also improving their periods. We also report new RR Lyrae sub-type classifications for 65 variables and improve on the GCVS period estimates for 135 RR Lyrae variables. There are seven double-mode RR Lyrae stars in the sample for which we measured their fundamental and first overtone periods. Finally, we detected the Blazhko effect in 38 of the RR Lyrae stars for the first time and we successfully measured the Blazhko period for 26 of them.
- ID:
- ivo://CDS.VizieR/J/A+A/402/801
- Title:
- Runaway carbon stars of Blanco & McCarthy field 37
- Short Name:
- J/A+A/402/801
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We have been recently faced with the problem of cross-identifying stars recorded in historical catalogues with those extracted from recent fully digitized surveys (such as DENIS and 2MASS). Positions mentioned in the old catalogues are frequently of poor precision, but are generally accompanied by finding charts where the interesting objects are flagged. Those finding charts are sometimes our only link with the accumulated knowledge of past literature. While checking the identification of some of these objects in several catalogues, we had the surprise to discover a number of discrepancies in recent works.The main reason for these discrepancies was generally the blind application of the smallest difference in position as the criterion to identify sources from one historical catalogue to those in more recent surveys. In this paper we give examples of such mis-identifications, and show how we were able to find and correct them.We present modern procedures to discover and solve cross-identification problems, such as loading digitized images of the sky through the Aladin service at CDS, and overlaying entries from historical catalogues and modern surveys. We conclude that the use of good finding charts still remains the ultimate (though time-consuming) tool to ascertain cross-identifications in difficult cases.
- ID:
- ivo://CDS.VizieR/J/AN/338/671
- Title:
- RV measurements of eight spectroscopic binaries
- Short Name:
- J/AN/338/671
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Since early 2015 a new radial velocity monitoring campaign is going on at the University Observatory Jena. The aim of this project is to obtain current radial velocity measurements of selected single-lined spectroscopic binary systems, to re-determine and/or constrain their orbital solutions.
- ID:
- ivo://nasa.heasarc/skyview/rxte3_20k_flux
- Title:
- RXTE Allsky 3\-20 keV Flux
- Short Name:
- RXTE3_20k_flux
- Date:
- 25 Apr 2025
- Publisher:
- NASA/GSFC HEASARC
- Description:
- Rossi X-ray Timing Explorer was launched at the end of 1995 and up to now (2004) it has been successfully operating for more than 7 years. The mission was primarily designed to study the variability of X-ray sources on time scales from sub-milliseconds to years. The maneuvering capability of the satellite combined with the high photon throughput of its main detector (PCA) and high quality of background prediction (thanks to PCA intrumental group of LHEA, GSFC) has also made it possible to construct maps of the sky in energy band 3-20 keV. During its life time RXTE/PCA has collected a large amount of data from slew observations covering almost the entire sky. <p> We have utilized the slew parts of all RXTE/PCA observations performed from April 15, 1996-July 16, 2002 which amounts in total to approximately 50,000 observations. The exposure time at a given point in the map is typically between 200-500 seconds. The observational period before April 15, 1996 (High Voltage Epochs 1 and 2) was excluded from the analysis because during that time the PCA had significantly different gain and dependence of the effective area on energy. The data reduction was done using standard tools of the LHEASOFT with a set of packages written by M. Revnivtsev (HEAD/IKI, Moscow; MPA, Garching).<p> <p> The survey has several features. It has strongly different exposure times at different points on the sky that lead to strong variability of the statistical noise on images. Because of that the only meaningful representation of images is the map in units of statistical significance. After the detection of a source flux can be determined from the map in the 'flux' units. Map resolution is determined mainly by the slew rate of the RXTE (<0.05-0.1&#176;;/sec) and the time resolution of used data (16 sec, Std2 mode of the PCA). Sources can be detected down to the level of ~6e<sup>-12</sup> erg/s/cm<sup>2</sup>, but at this level the confusion starts to play an important role. Details of the survey are presented in the paper of Revnivtsev et al. (2004). Provenance: High Energy Astrophysics Department, Space Research Institute, Moscow, Russia; M PA, Garching, Germany. This is a service of NASA HEASARC.
