- ID:
- ivo://CDS.VizieR/J/A+A/630/A75
- Title:
- Six luminous red novae photometry
- Short Name:
- J/A+A/630/A75
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present extensive datasets for a class of intermediate-luminosity optical transients known as "luminous red novae" (LRNe). They show doublepeaked light curves, with an initial rapid luminosity rise to a blue peak (at -13 to -15mag), which is followed by a longer-duration red peak that sometimes is attenuated, resembling a plateau. The progenitors of three of them (NGC4490-2011OT1, M101-2015OT1, and SNhunt248), likely relatively massive blue to yellow stars, were also observed in a pre-eruptive stage when their luminosity was slowly increasing. Early spectra obtained during the first peak show a blue continuum with superposed prominent narrow Balmer lines, with P Cygni profiles. Lines of FeII are also clearly observed, mostly in emission. During the second peak, the spectral continuum becomes much redder, H{alpha} is barely detected, and a forest of narrow metal lines is observed in absorption. Very late-time spectra (~6 months after blue peak) show an extremely red spectral continuum, peaking in the infrared (IR) domain. H{alpha} is detected in pure emission at such late phases, along with broad absorption bands due to molecular overtones (such as TiO, VO). We discuss a few alternative scenarios for LRNe. Although major instabilities of single massive stars cannot be definitely ruled out, we favour a common envelope ejection in a close binary system, with possibly a final coalescence of the two stars. The similarity between LRNe and the outburst observed a few months before the explosion of the Type IIn SN 2011ht is also discussed.
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- ID:
- ivo://CDS.VizieR/J/AJ/159/43
- Title:
- Spectroscopically identified CVs from LAMOST survey. I.
- Short Name:
- J/AJ/159/43
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- A sample of cataclysmic variables (CVs) is presented including spectroscopically identified 380 spectra of 245 objects, of which 58 CV candidates are new discoveries. The BaggingTopPush and the Random Forest algorithms are applied to the Fifth Data Release (DR5) of the Large Sky Area Multi-Object Fiber Spectroscopic Telescope (LAMOST) to retrieve CVs with strong emission lines and with broad absorption lines respectively. Based on spectroscopic classification, 134 dwarf novae, 41 nova-like variables, and 19 magnetic CVs are identified from the sample. In addition, 89 high-inclination systems and 33 CVs showing companion stars are recognized and discussed for their distinct spectral characteristics. Comparisons between CVs from LAMOST and from published catalogs are made in spatial and magnitude distribution, and the difference of their locus in the Gaia color-absolute magnitude diagram (CaMD) are also investigated. More interestingly, for two dwarf novae observed through LAMOST and SDSS in different epochs, their spectra both in quiescence phase and during outburst are exhibited.
- ID:
- ivo://CDS.VizieR/J/AJ/144/81
- Title:
- Spectroscopy and photometry of CV candidates
- Short Name:
- J/AJ/144/81
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The Catalina Real Time Survey (CRTS) has found over 500 cataclysmic variable (CV) candidates, most of which were previously unknown. We report here on follow-up spectroscopy of 36 of the brighter objects. Nearly all of the spectra are typical of CVs at minimum light. One object appears to be a flare star, while another has a spectrum consistent with a CV but lies, intriguingly, at the center of a small nebulosity. We measured orbital periods for eight of the CVs, and estimated distances for two based on the spectra of their secondary stars. In addition to the spectra, we obtained direct imaging for an overlapping sample of 37 objects, for which we give magnitudes and colors. Most of our new orbital periods are shortward of the so-called period gap from roughly 2 to 3hr. By considering the cross-identifications between the Catalina objects and other catalogs such as the Sloan Digital Sky Survey, we argue that a large number of CVs remain uncataloged. By comparing the CRTS sample to lists of previously known CVs that CRTS does not recover, we find that the CRTS is biased toward large outburst amplitudes (and hence shorter orbital periods). We speculate that this is a consequence of the survey cadence.
- ID:
- ivo://CDS.VizieR/J/A+A/275/201
- Title:
- Stroemgren photometry of Dwarf Novae
- Short Name:
- J/A+A/275/201
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- A sample of 26 dwarf novae was observed in the Stroemgren photometric system. The observations were performed on 3 different seasons in 1986 January, February and July, with a 6-channel photometer attached to the 1.5m telescope if the Observatorio Astronomicao Nacional at San Pedro Martir, Baja California, Mexico. A number of standard stars were observed, and a nearby comparison star was observed for each object.
- ID:
- ivo://CDS.VizieR/J/PASJ/68/65
- Title:
- Superhumps in SU UMa-type dwarf novae
- Short Name:
- J/PASJ/68/65
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Continuing the project described by Kato et al. (2009PASJ...61S.395K), we collected times of superhump maxima for 128 SU UMa-type dwarf novae observed mainly during the 2015-2016 season and characterized these objects. The data have improved the distribution of orbital periods, the relation between the orbital period and the variation of superhumps, and the relation between period variations and the rebrightening type in WZ Sge-type objects. Coupled with new measurements of mass ratios using growing stages of superhumps, we now have a clearer and statistically greatly improved evolutionary path near the terminal stage of evolution of cataclysmic variables. Three objects (V452 Cas, KK Tel, and ASASSN-15cl) appear to have slowly growing superhumps, which is proposed to reflect the slow growth of the 3 : 1 resonance near the stability border. ASASSN-15sl, ASASSN-15ux, SDSS J074859.55+312512.6, and CRTS J200331.3-284941 are newly identified eclipsing SU UMa-type (or WZ Sge-type) dwarf novae. ASASSN-15cy has a short (~0.050d) superhump period and appears to belong to EI Psc-type objects with compact secondaries having an evolved core. ASASSN-15gn, ASASSN-15hn, ASASSN-15kh, and ASASSN-16bu are candidate period bouncers with superhump periods longer than 0.06d. We have newly obtained superhump periods for 79 objects and 13 orbital periods, including periods from early superhumps. In order that future observations will be more astrophysically beneficial and rewarding to observers, we propose guidelines on how to organize observations of various superoutbursts.
- ID:
- ivo://CDS.VizieR/J/PASJ/69/75
- Title:
- Superhumps in SU UMa-type dwarf novae
- Short Name:
- J/PASJ/69/75
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Continuing the project described by Kato et al. (2009PASJ...61S.395K), we collected times of superhump maxima for 127 SU UMa-type dwarf novae observed mainly during the 2016-2017 season and characterized these objects. We provide updated statistics of the relation between the orbital period and the variation of superhumps, the relation between period variations and the rebrightening type in WZ Sge-type objects. We obtained the period minimum of 0.05290(2)d and confirmed the presence of the period gap above the orbital period ~0.09d. We note that four objects (NY Her, 1RXS J161659.5+620014, CRTS J033349.8-282244, and SDSS J153015.04+094946.3) have supercycles shorter than 100d but show infrequent normal outbursts. We consider that these objects are similar to V503 Cyg, whose normal outbursts are likely suppressed by a disk tilt. These four objects are excellent candidates to search for negative superhumps. DDE 48 appears to be a member of ER UMa-type dwarf novae. We identified a new eclipsing SU UMa-type object, MASTER OT J220559.40-341434.9. We observed 21 WZ Sge-type dwarf novae during this interval and report 18 of them in this paper. Among them, ASASSN-16js is a good candidate for a period bouncer. ASASSN-16ia showed a precursor outburst for the first time in a WZ Sge-type superoutburst. ASASSN-16kg, CRTS J000130.5+050624, and SDSS J113551.09+532246.2 are located in the period gap. We have newly obtained 15 orbital periods, including periods from early superhumps.
- ID:
- ivo://CDS.VizieR/J/ApJ/734/12
- Title:
- Survey of novae in M31
- Short Name:
- J/ApJ/734/12
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We report the results of a multi-year spectroscopic and photometric survey of novae in M31 that resulted in a total of 53 spectra of 48 individual nova candidates. Two of these, M31N 1995-11e and M31N 2007-11g, were revealed to be long-period Mira variables, not novae. These data double the number of spectra extant for novae in M31 through the end of 2009 and bring to 91 the number of M31 novae with known spectroscopic classifications. We find that 75 novae (82%) are confirmed or likely members of the FeII spectroscopic class, with the remaining 16 novae (18%) belonging to the He/N (and related) classes. These numbers are consistent with those found for Galactic novae. We find no compelling evidence that spectroscopic class depends sensitively on spatial position or population within M31 (i.e., bulge versus disk), although the distribution for He/N systems appears slightly more extended than that for the FeII class. We confirm the existence of a correlation between speed class and ejection velocity (based on line width), as in the case of Galactic novae. Follow-up photometry allowed us to determine light-curve parameters for a total of 47 of the 91 novae with known spectroscopic class. We confirm that more luminous novae generally fade the fastest and that He/N novae are typically faster and brighter than their FeII counterparts. In addition, we find a weak dependence of nova speed class on position in M31, with the spatial distribution of the fastest novae being slightly more extended than that of slower novae.
- ID:
- ivo://CDS.VizieR/J/ApJS/197/31
- Title:
- Swift X-ray observations of classical novae. II.
- Short Name:
- J/ApJS/197/31
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The Swift gamma-ray burst satellite is an excellent facility for studying novae. Its rapid response time and sensitive X-ray detector provides an unparalleled opportunity to investigate the previously poorly sampled evolution of novae in the X-ray regime. This paper presents Swift observations of 52 Galactic/Magellanic Cloud novae. We included the X-Ray Telescope (0.3-10keV) instrument count rates and the UltraViolet and Optical Telescope (1700-8000{AA}) filter photometry. Also included in the analysis are the publicly available pointed observations of 10 additional novae the X-ray archives. This is the largest X-ray sample of Galactic/Magellanic Cloud novae yet assembled and consists of 26 novae with Super Soft X-ray emission, 19 from Swift observations.
- ID:
- ivo://CDS.VizieR/J/A+A/477/67
- Title:
- Systematic search for M31 novae from Schmidt plates
- Short Name:
- J/A+A/477/67
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- This paper reports on the detection of optical novae in our neighbour galaxy M 31 based on digitized historical Tautenburg Schmidt plates. The accurate positions of the detected novae lead to a much larger database when searching for recurrent novae in M 31. We conducted a systematic search for novae on 306 digitized Tautenburg Schmidt plates covering a time span of 36 years from 1960 to 1996. From the database of both ~3x10^5^ light curves and >~10^6^ detections on only one plate per colour band, nova candidates were efficiently selected by automated algorithms and subsequently individually inspected by eye. We report the detection of 84 nova candidates.
- ID:
- ivo://CDS.VizieR/J/A+A/434/1107
- Title:
- UBV(RI)c photometry of stars around V838 Mon
- Short Name:
- J/A+A/434/1107
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Extensive optical and infrared photometry as well as low and high resolution spectroscopy are used as inputs in deriving robust estimates of the reddening, distance and nature of the progenitor of V838 Mon, the 2002 outbursting event that produced a most spectacular light-echo.
