- ID:
- ivo://CDS.VizieR/J/A+A/300/323
- Title:
- NOT GL survey of multiply imaged quasars
- Short Name:
- J/A+A/300/323
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- A gravitational lens (GL)-search program, initiated in 1990 at the Nordic Optcal Telescope (NOT), has revealed several possible GL-candidates among a sample of 168 quasars (QSOs), chosen from three lists compiled by C. Hazard, D. Reimers and J. Surdej, respectively. Some of these candidates, selected for having close companions (within 5 arcseconds), were imaged in several filters and their colours compared. Low dispersion spectra of the most promising candidates were also obtained at the NOT and ESO New Technology Telescope (NTT). None of these has proved to be strong candidates of gravitational lensing effects. We present this new sample of QSOs and combine it with previously published optical QSO samples in a statistical analysis to yield constraints on flat cosmologies and galaxy velocity dispersions.
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- ID:
- ivo://CDS.VizieR/J/MNRAS/440/3402
- Title:
- Nova Cep 2013 (V809 Cep) UBVRI light curves
- Short Name:
- J/MNRAS/440/3402
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- BVR_C_I_C_ photometry and low-, medium- and high-resolution echelle fluxed spectroscopy is presented and discussed for three faint, heavily reddened novae of the Feii-type which erupted in 2013. V1830 Nova Aql 2013 reached a peak V=15.2mag on 2013 Oct 30.3 UT and suffered from a huge E(B-V)~2.6mag reddening. After a rapid decline, when the nova was {Delta}V=1.7mag below maximum, it entered a flat plateau where it remained for a month until solar conjunction prevented further observations. Similar values were observed for V556 Nova Ser 2013, that peaked near R_C_~12.3 around 2013 Nov 25 and soon went lost in the glare of sunset sky. A lot more observations were obtained for V809 Nova Cep 2013, that peaked at V=11.18 on 2013 Feb 3.6. The reddening is E(B-V)~1.7 and the nova is located within or immediately behind the spiral Outer Arm, at a distance of ~6.5kpc as constrained by the velocity of interstellar atomic lines and the rate of decline from maximum. While passing at t_3_, the nova begun to form a thick dust layer that caused a peak extinction of {Delta}V>5mag, and took 125d to completely dissolve. The dust extinction turned from neutral to selective around 6000{AA}. Monitoring the time evolution of the integrated flux of emission lines allowed us to constrain the region of dust formation in the ejecta to be above the region of formation of OI 7774{AA} and below that of CaII triplet. Along the decline from maximum and before the dust obscuration, the emission line profiles of Nova Cep 2013 developed a narrow component (FWHM=210km/s) superimposed on to the much larger normal profile, making it a member of the so-far exclusive but growing club of novae displaying this peculiar feature. Constrains based on the optical thickness of the innermost part of the ejecta and on the radiated flux, place the origin of the narrow feature within highly structured internal ejecta and well away from the central binary.
- ID:
- ivo://CDS.VizieR/J/A+A/580/A45
- Title:
- Nova M31N 2008-12a 2014 eruption in optical/UV
- Short Name:
- J/A+A/580/A45
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The Andromeda Galaxy recurrent nova M31N 2008-12a had been caught in eruption eight times. The inter-eruption period of M31N 2008-12a is ~1-year, making it the most rapidly recurring system known, and a strong single- degenerate Type Ia Supernova progenitor candidate. Following the 2013 eruption, a campaign was initiated to detect the predicted 2014 eruption and to then perform high cadence optical photometric and spectroscopic monitoring using ground-based telescopes, along with rapid UV and X-ray follow-up with the Swift satellite. Here we report the results of a high cadence multicolour optical monitoring campaign, the spectroscopic evolution, and the UV photometry. We also discuss tantalising evidence of a potentially related, vastly-extended, nebulosity. The 2014 eruption was discovered, before optical maximum, on October 2, 2014. We find that the optical properties of M31N 2008-12a evolve faster than all Galactic recurrent novae known, and all its eruptions show remarkable similarity both photometrically and spectroscopically. Optical spectra were obtained as early as 0.26-days post maximum, and again confirm the nova nature of the eruption. A significant deceleration of the inferred ejecta expansion velocity is observed which may be caused by interaction of the ejecta with surrounding material, possibly a red giant wind. We find a low ejected mass and low ejection velocity, which are consistent with high mass-accretion rate, high mass white dwarf, and short recurrence time models of novae. We encourage additional observations, especially around the predicted time of the next eruption, towards the end of 2015.
- ID:
- ivo://CDS.VizieR/J/MNRAS/435/771
- Title:
- Nova Mon 2012 BV(RI)c light curves
- Short Name:
- J/MNRAS/435/771
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present and discuss accurate and densely mapped BVR_C_I_C_ light curves of the neon Nova Mon 2012, supplemented by the evolution in Stromgren b and y bands and in the integrated flux of relevant emission lines. Our monitoring started with the optical discovery of the nova (50days past the first detection in gamma-rays by Fermi-LAT) and extend to day +270, well past the end of the super-soft phase in X-rays. The nova was discovered during the nebular decline, well past t_3_ and the transition to optically thin ejecta. It displayed very smoothly evolving light curves. A bifurcation between y and V light curves took place at the start of the super-soft X-ray source (SSS) phase, and a knee developed towards the end of the SSS phase. The apparent magnitude of the nova at the unobserved optical maximum is constrained to +3<=V<=4.5. The appearance, grow in amplitude and then demise of a 0.29585 (+/-0.00002) days orbital modulation of the optical brightness was followed along the nova evolution. The observed modulation, identical in phase and period with the analogue seen in the X-ray and satellite ultraviolet, has a near-sinusoidal shape and a weak secondary minimum at phase 0.5. We favour an interpretation in terms of super-imposed ellipsoidal distortion of the Roche lobe filling companion and irradiation of its side facing the WD. Similar light curves are typical of symbiotic stars where a Roche lobe filling giant is irradiated by a very hot WD. Given the high orbital inclination, mutual occultation between the donor star and the accretion disc could contribute to the observed modulation. The optical+infrared spectral energy distribution of Nova Mon 2012 during the quiescence preceding outburst is nicely fitted by an early K-type main-sequence star (~K3V) at 1.5kpc distance, reddened by E(B-V)=0.38, with a WD companion and an accretion disc contributing to the observed blue excess and moderate H{alpha} emission. A typical early K-type main-sequence star with a mass of ~0.75M_{sun}_ and a radius of ~0.8 R{sun} would fill its Roche lobe for a P=0.29585d orbital period and a more massive WD companion (as implied by the large Ne overabundance of the ejecta).
- ID:
- ivo://CDS.VizieR/J/other/CoSka/39.43
- Title:
- Nova Tri UBV(RI)c light curves
- Short Name:
- J/other/CoSka/39
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the UBV(RI)c photometry of the dwarf nova Tri 2008 = OT J023839.1+355648 obtained during its superoutburst started on October 25, 2008. The object can be classified as a WZ Sge-type dwarf nova. The period of early superhumps 0.05307 days was detected in the first 7 days of the superoutburst. The period of ordinary superhumps 0.053663 days, detected in days 8-23 of the superoutburst, is the shortest one among WZ Sge-type objects. After one month, the dwarf nova returned to its pre-outburst state. A sudden increase of activity of the object during its quiescent stage was detected on January 11, 2009.
- ID:
- ivo://CDS.VizieR/J/A+A/543/A86
- Title:
- Nova V1280 Sco BVRcIcy light curves
- Short Name:
- J/A+A/543/A86
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present optical (B, V, Rc, Ic and y) and near-infrared (J, H, and Ks) photometric and spectroscopic observations of a classical nova V1280 Scorpii for five years from 2007 to 2011. Our photometric observations show a declining event in optical bands shortly after the maximum light, which took about 250 days to recover. This event was most probably caused by dust formation. The event was accompanied by a short (~30 days) re-brightening episode (~2.5mag in V), which suggests that there had been some re-ignition of the surface nuclear burning. After 2008, the y band observations show a very long plateau at around y=10.5 for more than 1000 days until April 2011 (~1500 days after the maximum light). The nova had taken a very long time (~50 months) to enter the nebular phase, according to a clear detection of both [OIII] 4959 and 5007 and is still continuing to generate the wind caused by H-burning. This finding suggests that historically V1280 Sco is evolving at its slowest ever measured rate. The interval from the maximum light (2007 February 16) to the beginning of the nebular phase is longer than any previously known slow novae: V723 Cas (18 months), RR Pic (10 months), or HR Del (8 months). It suggests that the mass of a white dwarf in the V1280 Sco system might be 0.6M_{sun}_ or lower. The distance, based on our measurements of the expansion velocity combined with the directly measured size of the dust shell, is estimated to be 1.1+/-0.5kpc.
- ID:
- ivo://CDS.VizieR/J/AJ/114/1190
- Title:
- NSV 09295: A double-mode RR Lyrae
- Short Name:
- J/AJ/114/1190
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- An analysis of more than 2000 CCD observations of the field RR Lyrae star NSV 09295 shows that the star is a double-mode RR Lyrae (RRd) variable with P_0_=0.46334d and P_1_=0.34423d. This brings the total of known field RRd stars in the Milky Way galaxy to four. These four variables are compared with the RRd stars in galactic globular clusters and with the field RRd stars in the LMC, and in the Draco and Sculptor dwarf galaxies. It appears that all known RRd stars have a metal abundance of less than [Fe/H]=-1.6. (c) 1997 American Astronomical Society.
- ID:
- ivo://CDS.VizieR/J/PASP/123/1149
- Title:
- NSV 11154 BVRI light curves
- Short Name:
- J/PASP/123/1149
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- NSV 11154 has been confirmed as a new member of the rare hydrogen- deficient R Coronae Borealis (RCB) stars based on new photometric and spectroscopic data. Using new photometry, as well as archival plates from the Harvard archive, we have constructed the historical lightcurve of NSV 11154 from 1896 to the present. The lightcurve shows the sudden, deep, irregularly spaced declines characteristic of RCB stars.
- ID:
- ivo://CDS.VizieR/J/A+A/627/A153
- Title:
- NSVS 10653195 light and velocity curves
- Short Name:
- J/A+A/627/A153
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Low-mass stars in eclipsing binary systems show radii larger and effective temperatures lower than theoretical stellar models predict for isolated stars with the same masses. Eclipsing binaries with low-mass components are hard to find due to their low luminosity. As a consequence, the analysis of the known low-mass eclipsing systems is key to understand this behavior. We aim to investigate the mass-radius relation for low-mass stars and the cause of the deviation of the observed radii in low-mass detached eclipsing binary stars (LMDEB) from theoretical stellar models. We developed a physical model of the LMDEB system NSVS 10653195 to accurately measure the masses and radii of the components. We obtained several high-resolution spectra in order to fit a spectroscopic orbit. Standardized absolute photometry was obtained to measure reliable color indices and to measure the mean Teff of the system in out-of-eclipse phases. We observed and analyzed optical VRI and infrared JK band differential light-curves which were fitted using PHOEBE. A Markov-Chain Monte Carlo (MCMC) simulation near the solution found provides robust uncertainties for the fitted parameters. NSVS 10653195 is a detached eclipsing binary composed of two similar stars with masses of M1=0.6402+/-0.0052M_{sun}_ and M2=0.6511+/-0.0052M_{sun}_ and radii of R1=0.687^+0.017^_-0.024_R_{sun}_ and R2=0.672^+0.018^_-0.022_R_{sun}_. Spectral types were estimated to be K6V and K7V. These stars rotate in a circular orbit with an orbital inclination of i=86.22+/-0.61 degrees and a period of P=0.5607222(2)d. The distance to the system is estimated to be d=135.2^+7.6^_-7.9_pc, in excellent agreement with the value from Gaia. If solar metallicity were assumed, the age of the system would be older than log(age)~8 based on the M_bol_-logTeff diagram. NSVS 10653195 is composed of two oversized and active K stars. While their radii is above model predictions their Teff are in better agreement with models.
- ID:
- ivo://CDS.VizieR/J/AJ/138/466
- Title:
- NSVS variables automated classification
- Short Name:
- J/AJ/138/466
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We have identified 4659 variable objects in the Northern Sky Variability Survey. We have classified each of these objects into one of the five variable star classes: (1) Algol/alpha Lyr systems including semidetached, and detached eclipsing binaries, (2) W Ursae Majoris overcontact and ellipsoidal variables, (3) long-period variables such as Cepheid and Mira-type objects, (4) RR Lyr pulsating variables, and (5) short-period variables including delta Scuti stars. All the candidates have outside of eclipse magnitudes of ~10-13.
