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.
The symbiotic nova RR Telescopii has been observed with the 3.9 m telescope at the Anglo-Australian Observatory (AAO), using the University College London Echelle Spectrograph (UCLES) in conjunction with a Tek CCD. It displays a rich emission line spectrum, ranging in excitation from NI to NiVIII. We present a list of 811 measured lines, with their suggested identifications and absolute line intensities, covering a wavelength range from 3180 to 9455 A. The absolute line intensities have been derived by comparing the high resolution data with a flux-calibrated low resolution spectrum taken with the Australian National University 2.3 m telescope. All of the lines have been successfully identified. Comparing our results with those of previous studies indicates that the RR Tel system is advancing towards higher degrees of ionisation.
We aim to study the spectroscopic and ionized structural evolution of T Pyx during its 2011 outburst, and also study the variation in degree of polarization during its early phase. Optical spectroscopic data of this system obtained from day 1.28-2415.62 since discovery, and optical, broadband imaging polarimetric observations obtained from day 1.36-29.33 during the early phases of the outburst were used in the study. The physical conditions and the geometry of the ionized structure of the nova ejecta was modelled for a few epochs using the photo-ionization code, CLOUDY in 1D and pyCloudy in 3D. The spectral evolution of the nova ejecta during its 2011 outburst is similar to that of the previous outbursts. The variation in the line profiles is seen very clearly in the early stages due to good coverage during this period. The line profiles vary from P Cygni (narrower, deeper, and sharper) to emission profiles that are broader and structured, which later become narrower and sharper in the late post-outburst phase. The average ejected mass is estimated to be 7.03x10^-6^M_{sun}_. The ionized structure of the ejecta is found to be a bipolar conical structure with equatorial rings, with a low inclination angle of 14.75+/-0.65{deg}.
The results of photometric UBVJHKLM observations of Nova Cygni 1992 performed from the 83d until the 290th day after the nova outburst are presented. The accuracy of the brightness estimate was better than 0.03mag for UBVJHK, 0.05mag for L, and 0.1mag for M bands.
Nova Cyg 2006 has been intensively observed throughout its full outburst. We investigate the energetics and evolution of the central source and of the expanding ejecta, their chemical abundances and ionization structure, and the formation of dust. We recorded low, medium, and/or high-resolution spectra (calibrated into accurate absolute fluxes) on 39 nights, along with 2353 photometric UBVRcIc measures on 313 nights, and complemented them with IR data from the literature. The nova displayed initially the normal photometric and spectroscopic evolution of a fast nova of the FeII-type. Pre-maximum, principal, diffuse-enhanced, and Orion absorption systems developed in a normal way. After the initial outburst, the nova progressively slowed its fading pace until the decline reversed and a second maximum was reached (eight months later), accompanied by large spectroscopic changes. Following the rapid decline from second maximum, the nova finally entered the nebular phase and formed optically thin dust. We performed a photo-ionization analysis of the emission-line spectrum during the nebular phase, which showed a strong enrichment of the ejecta in nitrogen and oxygen, and none in neon, in agreement with theoretical predictions for the estimated 1.0M_{sun}_ white dwarf in Nova Cyg 2006. The similarities with the poorly investigated V1493 Nova Aql 1999a are discussed.
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.
We present our UBVRcIc CCD photometry of a new dwarf nova OT J213806.6+261957 in Pegasus, discovered during its superoutburst on May 6, 2010 and classified as a WZ Sge-type star. In the term May 15 - November 27, 2010, we obtained more than 10000 CCD observations of the nova. Twocolour diagrams together with the superoutburst evolutionary tracks of the nova are presented. The analysis of our data revealed the presence of ordinary superhumps with the mean period of 0.055106d and late superhumps with the period of 0.05490d. We calculated the orbital period of the dwarf nova Pegasi 2010 to be 0.0542+/-0.005d and estimated the mass of the red dwarf component in the binary as 0.09+/-0.01M_{sun}.
Optical spectroscopic observations of the recurrent nova U Scorpii during its outburst in 2010 were obtained during 0.83-162.5 days after outburst maximum. Three spectra were obtained during pre-outburst quiescence. This paper discusses these observations along with optical polarimetric and radio continuum (610MHz, 1280MHz ; GMRT) data obtained during the 2010 outburst.
We present an overview of the UV spectral properties of old novae as a class. The data and results of this paper, together with data from the outburst phases, will be utilized in a follow-up study to determine statistical properties and to investigate correlations among the physical parameters of the quiescent and eruptive phases.
