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- ID:
- ivo://CDS.VizieR/J/AJ/99/1079
- Title:
- Nova rate in NGC 5128
- Short Name:
- J/AJ/99/1079
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the results of a five year nova survey of NGC 5128 performed with an H{alpha} filter at the prime focus of the CTIO 4m telescope. In all, 16 novae were detected, of which 12 are members of a statistically complete and homogeneous sample unaffected by the absorption lane of the galaxy. When normalized to B luminosity, the nova rate in the elliptical component of NGC 5128 is 2.7+/-1.0 times less than that observed in the bulge of M 31. However, when normalized in the infrared K bandpass, the two nova rates are identical, and comparable to that measured in the Large Magellanic Cloud. These data suggest that (1) the percentage of binary stars is approximately constant over a large range of star-forming environments, (2) the nova rate in our own galaxy is between 11 and 46yr^-1^ , and (3) nova rates are not strongly affected by tidal captures in bright globular clusters.
- ID:
- ivo://CDS.VizieR/J/AcA/64/197
- Title:
- OGLE-IV 2012-2014 transients
- Short Name:
- J/AcA/64/197
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the design and first results of a real-time search for transients within the 650 sq. deg. area around the Magellanic Clouds, conducted as part of the OGLE-IV project and aimed at detecting supernovae, novae and other events. The average sampling of about four days from September to May, yielded a detection of 238 transients in 2012/2013 and 2013/2014 seasons. The superb photometric and astrometric quality of the OGLE data allows for numerous applications of the discovered transients. We use this sample to prepare and train a Machine Learning-based automated classifier for early light curves, which distinguishes major classes of transients with more than 80% of correct answers. Spectroscopically classified 49 supernovae Type Ia are used to construct a Hubble Diagram with statistical scatter of about 0.3mag and fill the least populated region of the redshifts range in the Union sample. We investigate the influence of host galaxy environments on supernovae statistics and find the mean host extinction of A_I_=0.19+/-0.10mag and A_V_=0.39+/-0.21mag based on a subsample of supernovae Type Ia. We show that the positional accuracy of the survey is of the order of 0.5pixels (0.13") and that the OGLE-IV Transient Detection System is capable of detecting transients within the nuclei of galaxies. We present a few interesting cases of nuclear transients of unknown type. All data on the OGLE transients are made publicly available to the astronomical community via the OGLE website.
- ID:
- ivo://CDS.VizieR/J/AcA/65/313
- Title:
- One thousand new dwarf novae from the OGLE Survey
- Short Name:
- J/AcA/65/313
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present one of the largest collections of dwarf novae (DNe) containing 1091 objects that have been discovered in the long-term photometric data from the Optical Gravitational Lensing Experiment (OGLE) survey. They were found in the OGLE fields toward the Galactic bulge and the Magellanic Clouds. We analyze basic photometric properties of all systems and tentatively find a population of DNe from the Galactic bulge. We identify several dozen of WZ Sge-type DN candidates, including two with superhump periods longer than 0.09d. Other interesting objects include SU UMa-type stars with "early" precursor outbursts or a Z Cam-type star showing outbursts during standstills. We also provide a list of DNe which will be observed during the K2 Campaign 9 microlensing experiment in 2016. Finally, we present the new OGLE-IV real-time data analysis system: CVOM, which has been designed to provide continuous real time photometric monitoring of selected CVs.
- ID:
- ivo://CDS.VizieR/J/ApJS/187/275
- Title:
- Photometric histories of recurrent novae
- Short Name:
- J/ApJS/187/275
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- I collect virtually all photometry of the 10 known galactic recurrent novae (RNe) and their 37 known eruptions. This consists of my modern measures of nearly all archival plates (providing the only data for half of 37 known eruptions), my own 10000 CCD magnitudes from 1987 to present (providing virtually all of the magnitudes in quiescence for seven RNe), over 140000 visual magnitude estimates recorded by amateur astronomers (who discovered half the known eruptions), and the small scattering of magnitudes from all the literature. From this, I produce various uniform products: (1) BVRIJHK comparison star magnitudes and BV comparison star sequences to cover the entire range of eruption; (2) complete light curves for all eruptions; (3) best-fit B and V light curve templates; (4) orbital periods for all but one RN; (5) exhaustive searches for all missed eruptions; (6) measured discovery efficiencies since 1890; (7) true recurrence time scales; (8) predicted next eruption dates; (9) variations on time scales of minutes, hours, days, months, years, decades, and century; (10) uniform distances and extinctions to all RNe; (11) BV colors at peak and UBVRIJHK colors at minimum, all with extinction corrections; and (12) the spectral energy distributions over UBVRIJHK. Highlights of this work include the discoveries of one new RN, six previously unknown eruptions, and the orbital periods for half the RNe. The goal of this work is to provide uniform demographics for answering questions like the "What is the death rate of RNe in our Galaxy?" and "Are the white dwarfs gaining or losing mass over each eruption cycle?." An important use of this work is for the question of whether RNe can be the progenitors of Type Ia supernovae.
- ID:
- ivo://CDS.VizieR/J/PAZh/34/270
- Title:
- Photometric parameters of Galactic novae
- Short Name:
- J/PAZh/34/270
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Based on visual estimates by AAVSO observers, we have constructed light curves for 80 Galactic novae flared up in 1986-2006 and determined the photometric parameters m_vis_(max), t_2_, and t_3_ for 64 novae. Using the empirical relation M_V_(max)=-10.66(0.33)+2.31(0.26)*log(t_2_) (Cohen, 1985ApJ...292...90C), we have obtained the absolute magnitudes at maximum and apparent distance moduli of the novae.
- ID:
- ivo://CDS.VizieR/J/MNRAS/491/655
- Title:
- Photometry and spectroscopy of RN LMC 1968
- Short Name:
- J/MNRAS/491/655
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present a comprehensive review of all observations of the eclipsing recurrent Nova LMC 1968 in the Large Magellanic Cloud which was previously observed in eruption in 1968, 1990, 2002, 2010, and most recently in 2016. We derive a probable recurrence time of 6.2+/-1.2yr and provide the ephemerides of the eclipse. In the ultraviolet-optical-IR photometry the light curve shows high variability right from the first observation around 2 d after eruption. Therefore no colour changes can be substantiated. Outburst spectra from 2016 and 1990 are very similar and are dominated by H and He lines longward of 2000{AA}. Interstellar reddening is found to be E(B-V)=0.07+/-0.01. The super soft X-ray luminosity is lower than the Eddington luminosity and the X-ray spectra suggest the mass of the white dwarf (WD) is larger than 1.3M_{sun}_. Eclipses in the light curve suggest that the system is at high orbital inclination. On day 4 after the eruption a recombination wave was observed in FeII ultraviolet absorption lines. Narrow-line components are seen after day 6 and explained as being due to reionization of ejecta from a previous eruption. The UV spectrum varies with orbital phase, in particular a component of the HeII 1640{AA} emission line, which leads us to propose that early-on the inner WD Roche lobe might be filled with a bound opaque medium prior to the re-formation of an accretion disc. Both this medium and the ejecta can cause the delay in the appearance of the soft X-ray source.
- ID:
- ivo://CDS.VizieR/J/ApJ/788/164
- Title:
- Properties of the known Galactic classical novae
- Short Name:
- J/ApJ/788/164
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Recurrent novae (RNe) are cataclysmic variables with two or more nova eruptions within a century. Classical novae (CNe) are similar systems with only one such eruption. Many of the so-called CNe are actually RNe for which only one eruption has been discovered. Since RNe are candidate Type Ia supernova progenitors, it is important to know whether there are enough in our Galaxy to provide the supernova rate, and therefore to know how many RNe are masquerading as CNe. To quantify this, we collected all available information on the light curves and spectra of a Galactic, time-limited sample of 237 CNe and the 10 known RNe, as well as exhaustive discovery efficiency records. We recognize RNe as having (1) outburst amplitude smaller than 14.5-4.5xlog(t_3_), (2) orbital period >0.6 days, (3) infrared colors of J-H>0.7 mag and H-K>0.1 mag, (4) FWHM of H{alpha}>2000 km/s, (5) high excitation lines, such as Fe X or He II near peak, (6) eruption light curves with a plateau, and (7) white dwarf mass greater than 1.2 M_{sun}_. Using these criteria, we identify V1721 Aql, DE Cir, CP Cru, KT Eri, V838 Her, V2672 Oph, V4160 Sgr, V4643 Sgr, V4739 Sgr, and V477 Sct as strong RN candidates. We evaluate the RN fraction among the known CNe using three methods to get 24%+/-4%, 12%+/-3%, and 35%+/-3%. With roughly a quarter of the 394 known Galactic novae actually being RNe, there should be approximately a hundred such systems masquerading as CNe.
- ID:
- ivo://CDS.VizieR/J/AJ/152/226
- Title:
- Radial velocities of 35 cataclysmic variables
- Short Name:
- J/AJ/152/226
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We report follow-up studies of 35 recently discovered cataclysmic variables (CVs), 32 of which were found in large, automated synoptic sky surveys. The objects were selected for observational tractability. For 34 of the objects, we present mean spectra and spectroscopic orbital periods, and for one more we give an eclipse-based period. Thirty-two of the period determinations are new, and three of these refine published estimates based on superhump periods. The remaining three of our determinations confirm previously published periods. Twenty of the stars are confirmed or suspected dwarf novae with periods shorter than 3 hr, but we also find three apparent polars (AM Her stars) and six systems with P>5hr. Five of these systems have secondary stars visible in their spectra, from which we estimate distances when possible. The orbital period distribution of this sample is very similar to that of previously discovered CVs.
- ID:
- ivo://CDS.VizieR/J/MNRAS/469/4341
- Title:
- Seven recent novae BVI light curves
- Short Name:
- J/MNRAS/469/4341
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The BVI light curves of seven recent novae (i.e. V1534 Sco, V1535 Sco, V2949 Oph, V3661 Oph, MASTER OT J010603.18-744715.8, TCP J18102829-2729590 and ASASSN-16ma) have been extensively mapped with daily robotic observations from Atacama (Chile): five belong to the Galactic bulge, one to the Small Magellanic Cloud and another is a Galactic disc object. The two programme novae detected in {gamma}-rays by Fermi-LAT (i.e. TCP J18102829-2729590 and ASASSN-16ma) are bulge objects with unevolved companions. They distinguish themselves by showing a double-component optical light curve. The first component to develop is the fireball from freely expanding, ballistic-launched ejecta, with a time of passage through maximum that is strongly dependent on wavelength (~1d delay between the B and I bands). The second component, emerging simultaneously with the nova detection in {gamma}-rays, evolves at a slower pace, its optical brightness being proportional to the {gamma}-ray flux, and its passage through maximum not dependent on wavelength. The fact that {gamma}-rays are detected at a flux level that differs by four times from novae at the distance of the bulge seems to suggest that {gamma}-ray emission is not a widespread property of normal novae. We discuss the advantages offered by high-quality photometric observations collected with only one telescope (as opposed to data provided by a number of different instruments). We also observe the effects of the wavelength dependence of fireball expansion, the recombination in the flashed wind of a giant companion, the subtle presence of hiccups and plateaus, and the super-soft X-ray emission and its switch-off. Four programme novae (V2949 Oph, V3661 Oph, TCP J18102829-2729590 and ASASSN-16ma) have normal dwarf companions: V1534 Sco contains an M3 III giant, V1535 Sco a K-type giant and MASTER OT J010603.18-744715.8 a subgiant. We also comment briefly on the maximum absolute magnitude relation with decline time (MMRD).
