- ID:
- ivo://CDS.VizieR/J/ApJ/837/45
- Title:
- 2006-2012 Rc-band & 4.8GHz obs. of AO 0235+164
- Short Name:
- J/ApJ/837/45
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Variability is one of the extreme observational properties of BL Lacertae objects. AO 0235+164 is a well-studied BL Lac throughout all electromagnetic wavebands. In the present work, we show its optical R-band photometric observations carried out during the period from 2006 November to 2012 December using the Ap6E CCD camera attached to the primary focus of the 70cm meniscus telescope at Abastumani Observatory, Georgia. During our monitoring period, it showed a large variation of {Delta}R=4.88mag (14.19-19.07mag) and a short timescale of {Delta}T_v_=73.5minutes. During the period of 2006 December to 2009 November, we made radio observations of the source using the 25m radio telescope at Xinjiang Astronomical Observatory. By adopting a discrete correlation function to the optical and radio observations we found that the optical variation leads a radio variation of 23.2+/-12.9days.
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- ID:
- ivo://CDS.VizieR/J/A+A/642/A193
- Title:
- Rc-band light curves of 6 lensed QSOs
- Short Name:
- J/A+A/642/A193
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present six new time-delay measurements obtained from Rc-band monitoring data acquired at the MPIA 2.2m telescope at La Silla observatory between October 2016 and February 2020. The lensed quasars HE 0047-1756, WG 0214-2105, DES 0407-5006, 2M 1134-2103, PSJ 1606-2333 and DES 2325-5229 were observed almost daily at high signal-to-noise ratio to obtain high-quality light curves where we can record fast and small-amplitude variations of the quasars. We measure time delays between all pairs of multiple images with only one or two seasons of monitoring at the exception of the time delays relative to image D of PSJ 1606-2333. The most precise estimate is obtained for the delay between image A and image B of DES 0407-5006, with {tau}_AB_=-128.4^+3.5^_-3.8_ days (2.8% precision) including systematics due to extrinsic variability in the light curves. For HE 0047-1756, we combine our high-cadence data with measurements from decade-long light-curves from previous COSMOGRAIL campaigns, and reach a precision of 0.9 day on the final measurement. The present work demonstrates the feasibility of measuring time delays in lensed quasars in only one or two seasons, provided high signal-to-noise ratio data are obtained at a cadence close to daily.
- ID:
- ivo://CDS.VizieR/J/MNRAS/351/1401
- Title:
- RcIcZ photometry of NGC 2547
- Short Name:
- J/MNRAS/351/1401
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present a catalogue of RcIcZ photometry over an area of 0.855 square degrees, centred on the young open cluster NGC 2547. The survey is substantially complete to limits of Rc=21.5, Ic=19.5, Z=19.5. We use the catalogue to define a sample of NGC 2547 candidates with model-dependent masses of about 0.05-1.0M_{sun}_.
- ID:
- ivo://CDS.VizieR/J/A+A/376/561
- Title:
- Rc light curves of 7 variables in M37
- Short Name:
- J/A+A/376/561
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- A CCD photometric study of the dense galactic open cluster M 37 is discussed. The majority of the analysed data have been obtained through an R_C_ filter in order to collect time-series measurements. The observations were carried out on seven nights between December 1999 and February 2000, and have led to the discovery of 7 new variable stars in the field. Three of them have been unambiguously identified as W UMa-type eclipsing binaries, while two more are monoperiodic pulsating stars, most probably high-amplitude {delta} Scuti-type variables. Two stars seem to be long-period eclipsing binaries without firm period determination. The individual light curve data are presented here.
- ID:
- ivo://CDS.VizieR/J/AJ/125/2307
- Title:
- Rc photometry of ENEAR survey galaxies
- Short Name:
- J/AJ/125/2307
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present R-band CCD photometry for 1332 early-type galaxies, observed as part of the Early-type NEARby galaxies (ENEAR) survey of peculiar motions using early-type galaxies in the nearby universe. Circular apertures are used to trace the surface brightness profiles, which are then fitted by a two-component bulge-disk model. From the fits, we obtain the structural parameters required to estimate galaxy distances using the Dn-{sigma} and fundamental plane relations. The photometric data reported here represent one of the largest high-quality and uniform all-sky samples currently available for early-type galaxies in the nearby universe, especially suitable for peculiar motion studies.
- ID:
- ivo://CDS.VizieR/J/AJ/135/1488
- Title:
- Rc photometry of galaxies in NGC 5353/4 group
- Short Name:
- J/AJ/135/1488
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- This third paper in a series about the dwarf galaxy populations in groups within the Local Supercluster concerns the intermediate mass (2.1x10^13^M_{sun}_) NGC 5353/4 Group with a core dominated by S0 systems and a periphery of mostly spiral systems. Dwarf galaxies are strongly concentrated toward the core. The mass-to-light ratio M/L_R_=105M_{sun}_/L_{sun}_ is a factor of 3 lower than for the two groups studied earlier in the series. The properties of the group suggest it is much less dynamically evolved than those two groups of early-type galaxies. By comparison, the NGC 5353/4 Group lacks superluminous systems but has a large fraction of intermediate-luminosity galaxies; or equivalently, a luminosity function with a flatter faint-end slope. The luminosity function for the NGC 5353/4 Group should steepen as the intermediate-luminosity galaxies merge. Evidence for the ongoing collapse of the group is provided by the unusually large incidence of star-formation activity in small galaxies with early morphological types. The pattern in the distribution of galaxies with activity suggests a succession of infall events. Residual gas in dwarfs that enter the group is used up in sputtering events. The resolution of midlife crises is exhaustion.
- ID:
- ivo://CDS.VizieR/J/ApJ/850/195
- Title:
- RCW 57A NIR polarimetry and photometry
- Short Name:
- J/ApJ/850/195
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The influence of magnetic fields (B-fields) on the formation and evolution of bipolar bubbles, due to the expanding ionization fronts (I-fronts) driven by the HII regions that are formed and embedded in filamentary molecular clouds, has not been well-studied yet. In addition to the anisotropic expansion of I-fronts into a filament, B-fields are expected to introduce an additional anisotropic pressure, which might favor the expansion and propagation of I-fronts forming a bipolar bubble. We present results based on near-infrared polarimetric observations toward the central ~8'x8' area of the star-forming region RCW 57A, which hosts an HII region, a filament, and a bipolar bubble. Polarization measurements of 178 reddened background stars, out of the 919 detected sources in the JHKs bands, reveal B-fields that thread perpendicularly to the filament long axis. The B-fields exhibit an hourglass morphology that closely follows the structure of the bipolar bubble. The mean B-field strength, estimated using the Chandrasekhar-Fermi method (CF method), is 91+/-8{mu}G. B-field pressure dominates over turbulent and thermal pressures. Thermal pressure might act in the same orientation as the B-fields to accelerate the expansion of those I-fronts. The observed morphological correspondence among the B-fields, filament, and bipolar bubble demonstrate that the B-fields are important to the cloud contraction that formed the filament, to the gravitational collapse and star formation in it, and in feedback processes. The last one includes the formation and evolution of mid- infrared bubbles by means of B-field supported propagation and expansion of I-fronts. These may shed light on preexisting conditions favoring the formation of the massive stellar cluster in RCW 57A.
- ID:
- ivo://CDS.VizieR/J/AN/333/242
- Title:
- Recent photometry of symbiotic stars
- Short Name:
- J/AN/333/242
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present new multicolour (U,B,V,Rc,Ic) photometric observations of classical symbiotic stars, EG And, Z And, BF Cyg, CH Cyg, CI Cyg, V1329 Cyg, TX CVn, AG Dra, Draco C1, AG Peg and AX Per, carried out between 2007.1 and 2011.9. The aim of this paper is to present new data of our monitoring programme, to describe the main features of their light curves (LC) and to point problems for their future investigation. The data were obtained by the method of the classical photoelectric and CCD photometry.
- ID:
- ivo://CDS.VizieR/J/MNRAS/418/2054
- Title:
- Recession velocities for fossil galaxy groups
- Short Name:
- J/MNRAS/418/2054
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Defined as X-ray bright galaxy groups with large differences between the luminosities of their brightest and second brightest galaxies, "fossil groups" are believed to be some of the oldest galaxy systems in the Universe. They have therefore been the subject of much recent research. In this work we present a study of 10 fossil group candidates with an average of 33 spectroscopically confirmed members per group, making this the deepest study of its type to date. We also use these data to perform an analysis of the luminosity function of our sample of fossil groups.
- ID:
- ivo://CDS.VizieR/J/A+A/625/A14
- Title:
- Reclassification of Cepheids in the Gaia DR2
- Short Name:
- J/A+A/625/A14
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Classical Cepheids are the most important primary indicators for the extragalactic distance scale. Establishing the precise zero points of their Period-Luminosity and Period-Wesenheit (PL/PW) relations has profound consequences on the estimate of H_0_. Type II Cepheids are also important distance indicator and tracers of old stellar populations. The recent Data Release 2 (DR2) of the Gaia Spacecraft includes photometry and parallaxes for thousands of classical and type II cepheids. We aim at reviewing the classification of Gaia DR2 Cepheids and to derive precise PL/PW for Magellanic Cloud (MCs) and Galactic Cepheids. Information from the literature and the Gaia astrometry and photometry are adopted to assign DR2 Galactic Cepheids to the classes: Classical, Anomalous and Type II Cepheids. We re-classify the DR2 Galactic Cepheids and derive new precise PL/PW relations in the Gaia passbands for the MCs and Milky Way Cepheids. We investigated for the first time the dependence on metallicity of the PW relation for Classical Cepheids in the Gaia} bands, finding non-conclusive results. According to our analysis, the zero point of the Gaia DR2 parallaxes as estimated from Classical and Type II Cepheids seems to be likely underestimated by ~0.07mas, in full agreement with recent literature. The next Gaia data releases are expected to fix this zero point offset to eventually allow a determination of H_0_ to less than 1%.
